Crocodile Specialist Group
Crocodile Specialist Group
Crocodile Specialist Group
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CROCODILES<br />
krrcelrlirft$ of al* lllh Wortiry Mtrtir{ of lhe <strong>Crocodile</strong> Specidba Gntup<br />
of tl|c SFi{! $r vrl Cotnmbsi,on of ahc ruCN - fhc World Cot|scrvrtk n Udon<br />
aodvllrcd |.<br />
Vicro.ir Ft|lls, Zimbrbwe, 2 lo 7 August lt!t!<br />
Volune 2<br />
(Uncdilrd und Unrericted)<br />
ruCN - The World Conscrvrtion Uniott<br />
Avefir du Mo|rt Blnn , CH-llf' Ghnd' S*it .rtond<br />
:r.
FOREWORD<br />
The two volumes of this PROCEEDINGS are a record of the presentatiotrs<br />
discussions<br />
and<br />
tlat occurred at the I I rh<br />
^Workiug Meetirj .f,i" ii*Jil\*i"fi.t<br />
<strong>Group</strong> iD Victoria Fa s,<br />
Zirrtbabwe, 3-7th Au"gust LS9i.- Ti;,ruui;"s<br />
uore\lewed and uDedited. Tbe CSG pROCEEDINGS.<br />
by definition, ire records "*<br />
what<br />
of<br />
occured a-t the-meetiDg. They are not tomes filled s/ith articl€s that were<br />
reuewed, edtted, revised atrd polished subsequent to tbe meetiDq. ADan from<br />
preparDg a tabte ot coDteDts. ot_and_pasting captiotrs to figures, compiling<br />
articles<br />
the<br />
alphabetically by author, and numbeiing'the p"g". 3"nr"*tiuJfi' tl" p"p"r,<br />
.T,ry.blt:}.d j":, rhe way tbey were submittedl por'this reasou. ,t"y<br />
vanety<br />
Jfp.", ,o<br />
ot tormats aDd typefaces. laD Cames was the mauaging editoi "<br />
'<br />
The opinioas expressed<br />
herein are those of the individual authors and are not ttre<br />
:piqions-oJ IUCN - The World Conservation Union, ", it, Sp""i", Su-JLf<br />
L Olllmtsslon.<br />
IUCN - The World Conservation Union was foutrded itr 194g, and has<br />
headquarters<br />
its<br />
in Gland, Switzerland; it is an ildepetrdetrt iot"routioout ioay *tor"<br />
T:b-"j:hll j-"11ryjes stales,(irrespecJive of rheir potiricat<br />
goverument departmeDts. and private iDstitutioDs, as well as ""a international "*i"f"yrt"..),<br />
orgaDrzahors. lt represenrs those who ale concerned about man's modification<br />
natural environment<br />
of the<br />
tbrough the rapidiry of urbatr ioaurt iui a"r,"top_"ot<br />
the excessive<br />
uoa<br />
exploitatiotr o-f th" ."rih', outurul ,.ro"r""r".;;;;;l.t'ii" "oa<br />
foundations<br />
*.<br />
of his survival. IUCN,s main purpose i, i. ;;;;;" ;;;;;ort<br />
which<br />
actioo<br />
will eosure the perpetuation of wird nature uoa oitur"i ,.rouri"'Jon<br />
wide<br />
a worrd-<br />
basis, rot onry for their i,tritrsic curturar *i"tti-ti" *i."" i"iiiso<br />
long-tetm<br />
ror tae<br />
ecotromic and social welfare of mankind. "t<br />
This objective can be achieved through active conservation programmes for<br />
use<br />
the<br />
of natural<br />
v.ise<br />
resources in areas wheie the flora and fuuo"'"r"'of oliii"ur",<br />
a.nd<br />
lTf"th:".<br />
where the laDdscape is especially teautinrl or strifins.<br />
trEroncar<br />
or of<br />
curturar, or sciendfic sigoificance. IUCN berieves that<br />
aclieved<br />
its ;ims can be<br />
mosr effeclively by inter-natiooal effor, i. Ur[<br />
rorertrauouat<br />
.ii.,<br />
agencies, such as UNESCO. FAO. and "."p.r"ri." Ulgp, ana interDatioDal<br />
orgauisations, such as World Wide Fund for Nature (WWFj. -<br />
Survi!".t<br />
3.-iltj.^". ?l ]YaNs.Species<br />
Commissiou (SSC) is ro prevetrr the<br />
exotrcuon ol specres, subspecies, aDd_ discrete populations of fauna and<br />
maintaiuing<br />
flora thereby<br />
th_e generic diversity of tbe-living ip."i., pl"n.i<br />
mission,<br />
fl carry<br />
the "ftt"<br />
out<br />
SSC<br />
its<br />
relies on a network of oueiZJ0O uotunt."ifrof.".io-rj.<br />
through.<br />
*"rt<br />
more ttran<br />
og<br />
90 <strong>Specialist</strong> <strong>Group</strong>s and a large numbei 6i unifiui"irg"oirrtioo.,<br />
regional represettatives, and consultants, scatterej through o""riy-*".y<br />
"o,rotry ot<br />
tbe world.
Mkanda,<br />
Malawi.<br />
Moler, P:<br />
USA<br />
TABLE OF CONTENTS<br />
Volume 2<br />
F X: Ranching the Nile crocodile Crocodylus<br />
niloticus in<br />
Growth and **ival of Crocodylus<br />
acatrs in south Florida,<br />
Murpurgo, B: Growth rates aud food conversion efficiency in Nile<br />
crocodile hatchlings fed pelletized food.<br />
Murpurgo, B: Age composition of captive female Nile crocodiles and<br />
tbe effect on parricipation of young fimales in reproduclive activity.<br />
Murpurgo, B: Pond structure; the relation to hierarchv and<br />
reproductive acrivity in male caplive Nile crocodiles.<br />
Ouboter, P E: Status and conselvation of crocodilians<br />
in no heastern<br />
Belize.<br />
Perciral, H F, Masson, G R, Rice, K G & Woodnard A R: Arnerican<br />
alligator Ulligaror hississippinsk) clutclr viability from seven study<br />
arcas tn ftoflda. uJA.<br />
Rahman, M M: Utilization of crocodile resource for rural<br />
development programme in Bangladesb.<br />
Rao R J: Conservation status of crocodiles in the Madhva pradesh.<br />
India.<br />
Rice, K E, Perciral, H F, & A R Woodward: Alligator trest detection<br />
probabilities du ng aerial survey<br />
in Florida.<br />
Ratanakorn P: <strong>Crocodile</strong>s<br />
in Carnbodia.<br />
Santos, S A, Nogueria, M J S, Pinheiro, M S, Mourao. G M &<br />
Campos. Z M S: Condition factor o[ Caiman crocodil$ yacqre in<br />
different habitats of Pantanal Malo-Gtossense.<br />
Santos, S A & Pinheiro. M S: Composition and energy values of some<br />
tood rfems ingested by Caiman crocdilus yacare in the Brazilian<br />
Panata[al resion.<br />
lll<br />
l4<br />
15<br />
16<br />
18<br />
30<br />
31<br />
46<br />
64<br />
77<br />
78
Seiias, A E: Status of Orinoco crocodile populations in some localities<br />
itr the Venezuelan llanos.<br />
Shrestha T K: Ranching crocodiles in the himalayan waters of Nepal.<br />
Singh, L A K: Indian mugger - tenitorial resource partitioning and its<br />
implicatioDs<br />
in sanctuary managemeDt.<br />
Staton M A: Crocodilian conservation and commerce: Common<br />
interests prevail in sustained use managemant.<br />
Strton M A, vernon B P, & B Bon: The influence of dietary prawn on<br />
the production perfonnance of young saltwater crocodiles<br />
(Crocodvlus oorosust.<br />
Stuebing R B, & S A Mohd.Sah: Distribution, population strucrure<br />
and some aspects of the ecolog/ of the estua ne crocodile<br />
(Crocod],lus porosus Schneider) iu the Kilas River, Sabah<br />
Taylor, R D, Blake, D K & Loveridge, J P: <strong>Crocodile</strong> numbers on<br />
Lake Kariba, Zirnbabwe and factors influencing them.<br />
Vac M H, Verdade L M, Meirelles C F, Larsen R E, Michelotti F,<br />
Rangel M C, Salem C Z, & A Lavorenti: Ultrasound evaluation of the<br />
follicle development in adult female broad-nosed caiman (Caiman<br />
latirost s)<br />
Velazco A, & J Ayarzaguena: Population status of the spectacled<br />
caiman (Caiman crocodilus) in the venezuelan plain lSiatus de las<br />
poblaciones d.e baba (gSlrnSfLlp9pdi!@) someti.las a aprovechamiento)<br />
Verdade L M: Agonistic social behaviour of broad-nosed caiman<br />
(Caiman latirostris) in captivity: implications to reproductive<br />
management.<br />
Verdade L M, & M E B Santiago: Status of captive population of<br />
broad-nosed<br />
caiman (Caiman latirost s) in Brazil.<br />
Verdade L M, Lavorenti A, Michelotti F, Rangel M C, Cullen L, & M<br />
M Ernandes: Preliminary notes on nesting biology of the broad-nosed<br />
caiman (Caiman latirostris) in Sao Paulo, Brazil.<br />
Webb G J W Manolis S C, Ottey B, & A HeFrard: <strong>Crocodile</strong><br />
m?tnagement and researclr in the noithern ter torv: 1990-1992.<br />
iv<br />
79<br />
80<br />
88<br />
134<br />
148<br />
149<br />
1,63<br />
176<br />
184<br />
200<br />
218<br />
226
CROCODILES<br />
Proceedings<br />
of the llth Working M€€ting of the Cmcodile Speci$list <strong>Group</strong><br />
of the Species Survival Commission of the ruCN _ The World Conser-vation Union<br />
conv€ned Rt<br />
Victoria Falls, Zimbabwe, 2 to 7 August 1992<br />
Volume 2<br />
(Unedited and Unr€vierved)<br />
IUCN - The Wortd Conservation<br />
Uniur<br />
Avenue du Mont Btanc, CH-1196, ctand, Switzertand
Literature citatiots should be rod as follows:<br />
For indiridual articles:<br />
tAutho.I. 1992. lArticle Titrel. pp. tnumbers] r, C.ocodils. Pro{€dinss or the llih workina Meting of th€<br />
Lro"ooil spoiuri"t c-up of trre specie srrvi,al conmission of rhe lucN - The world conseriarion union, Grand,<br />
Switzcrland. votune 2. ISBN 2-81r7-0r33-l<br />
['or the volume:<br />
crocodile sp€cialisr <strong>Group</strong>. 1992. Crocodit€.. P.oce€din8s of the llth working Me€tin8 of the cncodile specialist<br />
cmuD. tUiN - Th€ worid Conservaiion Union, Gtatrd, Switze.land. volune 2 ISBN 2-8117-0133-3<br />
(d 1992 IUCN Int€rDttional Union fot thc Conservatio! of Naiure ard Naiural Rcaorrc6<br />
R€Prcductionofthispoblicationforeducationdadothernon{omnercialpurposeeisauthoris€dwithoutpe.nigsion<br />
fmn the @pftbr holder' provid€d the source is cited nnd the copJright holdg r€ceiv€' a copv of the 'eproduc€d<br />
Repm{tuctionforr€sa|eorothercommerclalpurpos€sisp.ohibited*ithourpriorwritt$pernissionofthecop'ri8ht<br />
hold€r<br />
rsBN 2-8Jr7-0133-3<br />
Pnblilhed by: IUCN/SSC Cro.odil€ Specialilt <strong>Group</strong>
Wilken D W Staton M A, Vernon B P, & B Bon: Artificial incubatjon<br />
of saltwater crocodile lCrocodvlus porosus.; eggs.<br />
Woodward A R, Moore T C, Delany M & T Hinesi The effects of<br />
cropping on Amedcan alligator populations<br />
in Florida, USA.<br />
List of Participants<br />
2',76<br />
277<br />
2'79
9cllgr<br />
Rahch.trE ths nile crocodila<br />
in l'lala!,1<br />
9:99-o-dy-f 9:<br />
F.X. flkanda<br />
KasurEU Na tloml Pa !k<br />
Box 4f,<br />
K€aurqu<br />
llA LAI,J I<br />
nilo ticus<br />
fhe Dranglra cEocodlle ranch presently hatches bebresn i?OO ano 2OUU<br />
hatchlirgs, oogtly frorn €ggs co.llected in th6 uild. Its orln b.e6_<br />
dlnq s tock of 4 mals6 and 9 f€nElgs ploducBd 29? 6gqs f.om 1t<br />
clr.rtch6a du.inq th6 psllod 19A4-1gAg. lb produce 2OO0 hatchtirEs<br />
at a hatchtrg sfrcco66 of 80d,'fi nortatlfy, and 1q st€rility, tna<br />
tanch lnus t col.lact 2800 eggs. About Z4 n6sts with an avalaqo<br />
clutch sizs of l8 eqqs hav6 tD be excavatod.<br />
lha .anch'a prcJ6cted targgt is 1600 sktn6 p€r annuflr. Ihis is th€<br />
export qoota app.ov€d by CI TES (Ole Convenllon on Int€rratioml<br />
T.ade in EndarEersd Sp6cl.es of Flora and launa). To achisve this<br />
tho ranch has already bred 4? f6|tEles to briro ths to tal. blooding<br />
stock to 60. In 1988 Sre mnch ar,po.ted ?00 skins. Fifty yourq<br />
crocodiles had baon .6hrrn€d to tho Nkhotakota Came RsservE in<br />
'1987 as a corBor\ration lneasure. Ftfty rrols clocodilBs ate due fo!<br />
r€le88e into ths rdseEve in 1990.<br />
&_tlgd!g_t_I:o!<br />
p16t,iously u,ildllfe ranchirA lras associat€d solely utth co,nn€rciat<br />
,no tiv€s. Ho!,rver, 1t is slou,Iy b6ln9 acknour'l6dg€d as s cons6lvation<br />
measure. It ls s naans of rel.t€ving prsssrrr€ on the urild nonulaticn:r<br />
as nuch aa savlng spaciss lfiat ar6 thraaten6d ulth srtinction.<br />
Frankel and SouU (1981) quotgd th€ Declalstion of B.?edirp ot<br />
Ehdanqefod sp6cl6s as an Atd t! thol. survival tiat'itia br€.dir4 of<br />
endangsrod species and subspecies of a"imal6 in captivity is likol].
to b€ crucial to ths suavival of many folms' It must lh€r'ofote<br />
be used as a method of prov€ntl'q €xtincttont alorqsidE ti€<br />
fiElntomnco of ths ll,itd 6 tocks in thel! natlral habitad''<br />
pionddr t/o.k on lri!.dllfs .anchlrq v'as conducted in zltnb6bue (th6<br />
then Rhod€616) in ttre 195os (wtllianEon and payn€' 19?8)' capttve<br />
'1?'8)<br />
br€artlrq of c.ocodiles (IggoOyfus nlloticus Laursnti fol<br />
purposss of rostockim dopl6t€d u'a teF'ays u'ar first achiev€d in<br />
19?4 nt r\t.tlrnu Cane Resetve .in South AFrica. A total of 898 yourg<br />
c.ocodilss have b6en r€l€ased lntD sevetat difl€t6nt locaIltl€B<br />
u.d6a thls schomo operat€d by tha Natll parke Eo6ld (pooleyt 1980a)'<br />
lhe schsE€ h63 slnc€ spread out to other pa!t! oF Afrtcat fo' €xample<br />
th€ captlve bt6€d1rg of crocodlleB In Nigerta for pu'pos€s of re-s tt-<br />
ck1ru urat€.oays and releasi in paFdam 6ama Res€'vE (tlorgan - Ltavigs,<br />
198o). crocodua falntnq for com|nercl6l purpose is btirg invostigat€d<br />
1n Ivory Coast, Zaobiar l4ozambique' and South Africa (pooloy, 1980b)'<br />
Crocod1l6 lanching Is a ne!, concept in t't6l6u'i' th€ fi'st mnch u'as<br />
6stabllshFd by the Ooa rpu,a Sugar CorPoDatlon in 1984 in lJkhotakota<br />
district (Fts. 1). A second on€ has recantly bBen Establlshod in<br />
tilan.tochl. gec€use of tlte Buccsss achiev€d to &tG the &rargt'a mnch<br />
acts as 6 modsl. Yet f6!i ptoplo krou of its 6xis t€ncet let alon€ its<br />
activltl€s. thl3 paper th..afors pre3snts 1'forrl'atioh on the backglound<br />
to the Oxa.gua crocodilg ranch and th6 progr€Es nad€ so fa"<br />
qpjlr.tiyg. !|9- .1_t-r9r919 fo! th6 ranch<br />
Tho prinary ohjBcttve of tho ranch 13 to contributo to the conseiva tion<br />
ol the .ila crocodilo ln l1ala{ii (S tlover' pers. cornm.<br />
)'<br />
objective, urhtch ls palt of divsrstflcatlon of ti6 oetatsrs<br />
fhe subsldiarv<br />
actlviti6s' 1s to utlllzd thd crocodil€ sus tairably fo! oconomlc bendlit6'<br />
If tho ranch ls to bs nanaged affectivslly' lt !s only ratioFal that tt<br />
i5 6co rnlcally viablo.<br />
Altho'roh the crocodilo i3 prottctdd und€r lhe Crocodil€ Actt Cap' '
Figl; Mop of Mobwi: shoryiing t ktbnol porks, Gorna Raszrvcs ond locouon of<br />
Dwongi\^,o<br />
crocodile mrch.<br />
KtrY<br />
. tl|z D^/orgws crodila mnch<br />
: @na Rzsarv"s<br />
fln[t Nbtbndl PorKs<br />
0 50 1@ 15OKm<br />
1 Dryornbrol River<br />
2 D^/ongwo Rivar<br />
J t]Ja Riva-<br />
4 Krynb@ Rivar<br />
Lu\^/eyo Ri\^zr<br />
o t -Ou,rzr Shir"z<br />
3
f!:oction ol ths tDtal poPulatton is resldsnt in I nut of tho 9<br />
protsct€d ardas ma.agsd by the D€pa!t'n€nt of Natior'al Parks<br />
an.J lilldllfd<br />
(Di,rt'J<br />
). fha t protect€d arsas u,it}r clocodil€ popu-<br />
lations arel Litlonda Na tional parkr ikjat€ Cams R€ao.v€r and<br />
Nkhotakota cane Ras6rvs (Ftg. 1).<br />
thor€ are conlltcts botuden crocodtlbs Bnd th€ hunan populEtlon.<br />
For irstancg crocodilBs dss troy flshtrq nsta ruch to the anrro-<br />
yance of fish€rman. lhay also d6s troy livestockr hudian lif€, and<br />
somBtln€s main peopl€. thoee co"f-Ilct€ ar€ anouoh fo! the publlc<br />
to rJev6lop nsgativ6 attitudes tbu,atda croco.Jites. llence th6 formsr<br />
suize evory opportu.ity t €xcavate crocodlle nr6 tE aFd des t.oy<br />
thoir arns. In somr i:aslrs thD eqqs may bc colltcted for othdr purDoses'<br />
or they ars simply dis turb.rd uhil€ In ths osst. lhsre is evldeFc€<br />
th6t ohcF ^Ests havs boon,.xcavated and eqqs car-Eles":ly handled th€<br />
embr.vos do -dt cortihuo to .lavelop. Strov€r (1989) rpPortsd of t<br />
casas ,uh.re ooos uFra u.FartlPd a..l dishrrbed by Iocal flshermRh.<br />
lh€ omtr.yos in such Boits st pp.rrl cl6veloPl nq. In a.lrlttion ht eag<br />
d€sj:ructionr collection or disturbance by nanr uiat€r monltor llzatds<br />
Va.r?j99 j.'i l9.r]9!r9 rob croco.lil€ "est3 (HacJikhula' n!.3. comn).<br />
FurlhEr nan-crocodilo co.fticts involv€ crocodjlp habi ta t .Jos tructioF.<br />
J^ ltra.! auri tha ctocodi16 occu.s 1n a vari6ty of frslrh{ra tar habitats<br />
such as lakos, la!(16 rivF!s, suamps, marshes, ard riv.rr droulis. lhese<br />
arEas are also es6c.tial for aqr-icu1fu.e, fisherirs' and hydroelectrtc<br />
pDu'!i.r<br />
oonera tion.<br />
Some ftarsh6s havB isla-ds tuhich a!E lcieal lor dry season cL'ltivation.<br />
Exannlos ale the Elepha"t snd lttil-dl marsh€s ubich havo ths ders€st<br />
crocodile cD.ce.tration in the lottt -"t Shlre Rlver. Dry soason culti-<br />
vatjoF e.ha.ces food sscurity and it ls increasi.q in 1ts ltnportancB<br />
(Fr6|lnan, 19?4). lhls lncrdase ts p.obably due to the mou^tlrg honan<br />
oress',re on cultivabl6 land. As a resultr more islaFds v,lll bs<br />
sub.jocred tD cultivation tn€rsby rlas troyi.q ooe of the crocorllle<br />
Sa-dv b4achos ar€ .astirgr ]oafi.g,<br />
Yet thc lrarns FIac€s ara flehEr|nB"rs<br />
hn ror.j..t croco.lllos to retrrat t!<br />
sLl tahl e hahitats.<br />
and baekl.q r!rouFds for crocddtl6..<br />
la.dirq arounds. this co.fl ici. mioht<br />
safe! arEas hut nrobebly not
lhpoundlrg riva13 for purnoses of slectrlclty qsne!atlon or 'rr1-<br />
qation can bltrq about €Fvlrorneotal chanq6s both .lourns tream and<br />
uos traam' A sfudy tn tia ilaha poola Game Rbserve in ths hld-Za-<br />
nbo?l Ualley shoured th.t flood .€lea6€sr durirg the d.y saasont<br />
ot volumBs q.e6ter th6n th€ n6an dry leason flou, of ths pte-inpo-<br />
und'rsnt perlod ulll cleny loaflrq, baskirg, aod fe.dtrg of amphtbia,s,<br />
birds, and reptiles (Abr€ll, 1970). rhe relcasa utll also des troy<br />
th€Ee utlldllfa as much as thetr egqs 'r,hen they nest near to dry<br />
scason u,ater levele of th€ riv€. and ox-bou6.<br />
'lh-"se<br />
lmpacb may a€<br />
uetl ba takidl effect on the Rlver Shlre uher€ trsfe is a. impou-<br />
lhere are 2 folns of crocodil€ hunttrq in t4alauilt control shDottrg<br />
tr safeguard hum6n llfe and prop€rty, and llce.cod huatlrla.<br />
cro.odils poachirg has "ot bee. dstectFd durtnq the last 10 yrntg<br />
(Dspartm6nt of National park6 a^d tilldllfe, 1989).<br />
Follotuing a major concern tn }ourist devBloplnsnt on Lake llala'tt uith<br />
pt.ticular r6sp6ct to oat€. sport, tt uas .J€cl.lsd that aIl c.oco.,tl,!'!<br />
bo oxlsd.lnatsd froD tourlst ar66s on Lak€ Malauri (Anon. 1971). To<br />
dat€ cohirol shoottro ts done, as paDt of Govsrrnent policy on<br />
crocodil€, -ot oFly in torr16 t r€3ort3 but 'lhF.RvFr maraudirD c.ocodiles<br />
IicencBd huntlrlq i3 subject to an 6xport quota approvGd by CITFS.<br />
Cur.EFtly th€ra br6 1l c.ocodil.e hunts.s tlhose activities €pan acro.s<br />
the country. Each ono hos a spgclflc atea ol oper?ttion. DatE obtained<br />
fro'n tha Cold S torage CorFany oF tlalaul, thE only loca] compaFy that<br />
buys and export6 ctocodiles 6kiri6r shorrs tha t b6fu€en 1976 a6d 19A6, a<br />
tota: of 41J, skin6 ur€re expo.t€d. lhe htqhs6t '?xport uas 1019 sklns<br />
tn 1981 (Flq.2). Aft€r th6 t.6nsfEr of tha ^tl€ crocodtlo lron lpr'^ .jlr<br />
1 to Appsndlx II l,lalaulrs quota uas 5O0 sktns tn 1985. In 198? an<br />
incFeas€d quo ta of 700 skins f.on the urild 'r6s apnrovod fo. €ach year<br />
urttl i'r'1989 uhon tt tas leduc€d to 250 fo! the year 1990. This off-<br />
tak€ is su8 tat.6bls (Departnent of NatiDnal parks and I,rildtlt€, 1989).<br />
tr.t1l 1989, hot ever, thsr6 u,aE no rcls.tlllc basls fof petaht iihlr(|<br />
off-tika quotas. Fot such purpo3ea th€ populatioh status of th€ nll.<br />
crocodlle in llalaurt has rot b€e. sstabllsh€d. lhs .rxis tlrg es tlma tas<br />
diffor hy a v.ry u,Ide marqin. l4phand6 (198.) rs ttrB t€d a mlniftum of
o<br />
Fgz Crocodlla skins @xport@d by Mohwi 1976-1966
dr^ r^d from Mth^ ^da (1r1i.
4.00 crocodtlelt ulth an tppsr llnit of 15'000 and a u'orkirg Ponulattnn<br />
nf 8000. thls has bsen critiatz6d as conseFvative. Anon. (1986)<br />
.lLjotrd by Department of ua tional Parks and Wildtifs (1989) 83tinatEd<br />
the crocodlle popula tlon to hsvd been Zlt3OO in 1"84. lhts larS6<br />
difforanca. b6tlteen as tlna t€s pos!:: dlfficulties in €stablishirO<br />
huntir'g quotas basod on 161iabl€ data. Hsnce th€r€ might hav€ bsen<br />
a danqe! assosistad urith tite hunting.<br />
Fo! sr,ch hig populationsr an averaqa off-take oF 411 skins bet!€an<br />
191A a^d'l9a6t Uh€n 7O0 skir€ frcm 1987 to ro89 Yot'Id hou,6v€l not<br />
havn afFscted the poFulation n€qattvsly. ln $is case though tt i3<br />
impos^ibl6 to ssgsss the impact of licercsd huntirq on ths population'<br />
ritslly because ol difficultlBs wtti the populatic,n estlmatae.<br />
SccoFdly, tiets have bssn no studies on tn€ blology (aqs structlr€)'<br />
..x ratios, rqprorjuctlor, mo.tal l ty ntc) o" lho ':r''{. dl1o in Utq<br />
ItouevEr, it trould appB6r Ulat a larqe proDortion of th€ off-take for<br />
thr pa6t 11 ysars comFrised crocodiles betttteen 1.5 m and Itn (Ftg. ,<br />
and 4) u,hich ar6 nostly 6ub-adults and adults. A small percdntaqe<br />
corslstad of l6rgo crocodiles (mora than I m lor{t) urhich in t}le case<br />
of f€males lay tndrs and latg€r eggs than thosd that have Just startld<br />
breo6i.g. IF this is rsflBctivc of ths 39s strtrcfutEt one lJould b€<br />
jncltned to conclude th6t thB population ts .ot 6 heal tlty one. lhea€<br />
has protrably bsFn ovat-€xploitation of old clocodilosr cor€iderinn<br />
ihat comm6':cial crocodlls hrr^tlng has be6n dons Einc€ lfie fi.st<br />
ssttlnrs arrl.ved in th6 country (D6parbr€nt of lId tioiol parks and<br />
utldltfe, 1989). Clfss (19?8) stated that Exptoitation of otd a-inal:r<br />
ts qehora.lly inversoly relatsd to th€ bata of t}|e futurs (aqe) pyramid;<br />
that ts tho mor6 int€'siv6 th€ €xploltatlon, tjis natrouot tho pyramld<br />
aqa tras6. F{q. 4 Buits thls s ta tsnBnt. In flala'"i hu.tirg ls selactivo<br />
l^ favour of big crocodilee. lhlB ls b€caus€ Ure CoId s to[age Companyt<br />
pays sccordli8 to lanqth of th6 3kin. lhis k incEntiva Brough lor<br />
hrintgrs to shoot blg crocodlle6. lhd inc.eassr betlrean 1.r-2.1m skin -<br />
lergth clas!, in th6 psrcentaqo of export€d sl
of sub-adults ard adJltt mrght ltnit r6cn'ibn6nt of largel fdFl€'<br />
0hlcfr 6te €rsentlal lol population osouth.<br />
tJith all tha fots-going actlvittes thr€tt€^irE lfte long-t€rfi su'vl-<br />
val of the crocadll. ln l|at6otr rsnc'htrg s€en's to be 6 viable corF6t_<br />
va tion and |||6.€gdtsnt proposltion.<br />
rbrE g gl-6.r'j-.oi-f :9S-o-d-49--t-$919i9!<br />
lhera are sevelal t|an€rg€n€nt ptsctic63 bairE carliod out by tho r'Fch'<br />
tt ts rot th€ pt rposc of thiE pap€r to d6tail all of therl. lhelefoDs<br />
onlv those practlcea de€oed televant tD highlightlt4 ths achievsnsnlp<br />
of thE ranch ale d€scrlbed in the succadlrq paraglapl€. lhea€ a'€t<br />
strcklrEr btoedirg, fcsdirEt ttnd cropplr€.<br />
lhs Dlang$a clocodlle ranch is 6ttratrd Juat abov€ the delta of tha<br />
CDar€oa Rtve! (Fig. f). fha lttarEua delt! ha! been horne of crocddil€s<br />
for :gee. lhe d.velopnsnt of aq.lculhrrll actlvltias in Ule sally<br />
1980s forced the crocodllee to tetrsat fulthat dolrrp t'e€m. Houl€vel<br />
adult3 and srrb-adulta lamol||bsrlr€ th€ta traditioral haunt€ and sBeklm<br />
nett hohes mov€d upstlaam and sought lefugE in tho Ftqht storago datE<br />
of th6 €st t€ (s trovorr<br />
'1989).<br />
thts ls hou the Eane'h acqulrsd its<br />
orlglnol<br />
e tock.<br />
tn 1984 the ranch colt€ct€d 20? egqa from the tr'lld 6nd i'crJbatsd thdn<br />
l. a medijn, of the factory ash. lhe tatrperaturt !,as mainttlFsd betll'eFn<br />
too rr.t rroc. Since then nolE ogor h6va been cotlectsd €tnd hatchod<br />
l^ the sane uoy (hbt. 1). Ptcee"tly the t6.ch hs tch6s batnebn 1700<br />
6.d 2000 h6tchltros per y66t. lha hatchlrq aucceas hals rar0od betoeer<br />
21.6 6.d 1oM dsps^dlr€ on th. Bourc. of tht .99s (Dble l). Hatchlra<br />
'rortallty 13 faltly lotr lfie hlghost bel'g 9t tn'1985 and 1989 (Tabfe ?)'<br />
'rhs ranch utll ultldEt€ly ttcraforh lnto.'fatn t}l(|s producirg it! oon<br />
egga (S trovarr par€. colflt. ). It thu! alnt at havirq a br€adlrtg 6tdck<br />
of (0 females. In th€ |tt66rrtJhi1€ it h.. only 4 brEEdtrg |nal€s 6nd 9<br />
fEfial*. lh€ prodrctlon ttE96t 13 proJectod Et 1600 skiis pel aF'un.
10<br />
lEble lr Hatchlrq auccess dat!, Dnangrra crocodllo rahch .19g4-1989.<br />
Loca tio n<br />
ftlsanrala<br />
Lq',rEr Shire<br />
r}l,anb6. i<br />
8re-rllrq pond<br />
&ra Rlv6!<br />
Likuchl<br />
Oe,na<br />
CIutrh€a<br />
72<br />
1<br />
11<br />
27<br />
6<br />
'l<br />
1<br />
1<br />
:::"<br />
1847<br />
112A<br />
2?72<br />
(n<br />
ttt<br />
100<br />
2A?<br />
11 66<br />
20t<br />
4t<br />
37<br />
.gge/cl u tch t -cuha ted hatched<br />
1718<br />
107 4<br />
2 604<br />
58<br />
41<br />
9?<br />
2AIt<br />
1097<br />
1<br />
41<br />
t6<br />
51<br />
To tal 2O4 7? ta ,8 470<br />
l!hl. 2t Hatchlirp nortality; Dlanguja crocadila ra.ch 1985 - 1989.<br />
19At<br />
194 6<br />
1987<br />
1988<br />
1949<br />
Sorrac€ ! st ov€r (1989)<br />
Hatchltrqs LOASeg<br />
178<br />
642<br />
1(7t<br />
2fitt<br />
1744<br />
J1<br />
54<br />
a5<br />
1t7<br />
(278 t6t<br />
f8<br />
t6<br />
'D<br />
4t<br />
50<br />
26<br />
4t<br />
t4<br />
4t<br />
,?<br />
4.4<br />
4.2<br />
'| 44? A4,2<br />
954 88.8<br />
21't3 at,4<br />
4? 81.0<br />
tJ ao.5<br />
77 ?9.4<br />
zlt 75.O<br />
1077 99.2<br />
169 A'.a<br />
4r ,0o.0<br />
2a ?1.8<br />
11 21.6
lho infrabt uc hrlo ol tfie es ta t€ provld.s storaee (brl, rnd abun(Ent<br />
uatF! lot p.odrrctlon of a re6dy food source (Strovsr, 1989). Food<br />
la .ot offered to the hatchllr{s unttl tha yolk t5 fully rb8orbed.<br />
For the flr6t 10 - 11 rnonthe, uhttl tho h.tchllr0 ale movgd to ths<br />
groui'ig out pede, lfie dlet ls €rctuslvsly flBh. ysaDlirqs ar6 k{_,p<br />
t<br />
pre.lonina4tly on.fl.sh di6t but suppl€iE.ted ,rri<br />
th chickon and oBre!<br />
llvestock mortallttes that oecur. lhe total annu€rl corFufitptlon of<br />
fE.d lor the ranch ls 80-100 toF-€s.<br />
Crocodil.ea of bebreun 1l ana 2l ysaF old aDt croppeda In i9O8 t}re<br />
ranch cxnorted 700 skirp to ltaty. I. 1989 the quota oas laissd !o<br />
1600. lhe croppire foldcast for 1998 ls 1620 crocodilgs. tt tg<br />
rE.luirad ol tie .anch 10F of tha 2-y6a. olds hat hsd fron €qqs qotlsct€d<br />
in irkhotal
t2<br />
:.oF j.r.rlaa,r tr -t,i-e tctt tlre.: tt39 a/ c--'::'eak ':f ^':ai_1csi9 '_!-_'<br />
rar'_acisd ha!.:li.9s and g.nLin-o stcck. Il ac:'u'too lor the 1o3s dl'<br />
l?? vEaflinqs and 2 - Y6ar olda.<br />
Du.i.g thE oast 2 s!334.s 199a/191 z devastati^e '._Citiei occur:ed<br />
i- clrrtthEs collactsd lram th€ 8ua live!. It has be'n dia,onosed a3<br />
a cal.ciuo imt:obiliz?tion y_dtom". It b believ6d tfiat this cordlton<br />
ls herect.ttary and b€lr€ pelpEtjat€d by th€ saiE 8ua clocodllas<br />
(Slrover, pats. com'n.<br />
). tris Ciseasa 3ccourt€C lot 4l of tfie hatchllrq<br />
loss€6 in 198? and about 45/" \n 196A. No €gqst theseforer {'€!e colle-<br />
cted floin t'le t€s6!t€ in 1968 and thale luslo .o cases of th€ corditlon<br />
in th6 1989 ha tchJ.irg6.<br />
Co-clus io n<br />
the iilo crocodile is undel thrsat ln l'Llatl,i fron hulEn actj.vitlEg<br />
such as huntirlr habitat d€3t$ction, and €99 d€structlon o! collg-<br />
ction. <strong>Crocodile</strong> lanchlrg off€ls an aIt€rnativ€ tE utlllzation of<br />
the u,ild population. S ta t$ tlca shdl, that l'|6 OirarE0,a lanch haa<br />
ranaq6d its clocodil6 Population ve.y a€ll. Such unde!lakir8sr tlt6!6-<br />
fo!6, should b6 further oncouraged in the countly.<br />
A.on. (19?1 ). Record of a ne€tirE on <strong>Crocodile</strong><br />
I{6l,au, i Cov€rnm6nL<br />
ln Laks t'tala0rl.<br />
A o:ells R.I.G. (19?O). son€ off€cts of Laks Xa.ibe on Itre scology<br />
of a floodolat. of th. mld-Zanbezl Valley of<br />
Rhodesia. -8i-"_99:9: 2 11)|<br />
1Be -1e6.<br />
D€patbrent of<br />
rlatio.el Palks and l{ildll?. {1989). tlainter.ance i.n<br />
Aope"dix II of the l4alauti pooulation of g:....9q]!9<br />
.iloticus. A propossl suboitt€d tt ths Tttr ttle€tlng<br />
6?-Eiit6.ference of 8rE pa.tiee.<br />
Lausa.r€, Su,itz6rland.<br />
Flark6l, O.H. a.d SouLer X.E. (1981). Cor€€tvation and evolutlon<br />
Cahbridqo t<br />
"iveFity<br />
Press. Ch. 6.
Frr€maF, '1. i1974). r srpIi:r,1^ary irte6ticatji^ rf cihba c.J I ti-<br />
vatio. in ttrs Lo{r6. ShIle Ua!,1.€y. a reoo! I t!<br />
l4alau,1 Govs.n'|tenL<br />
Ciles, R.H. (19?8). Wildfife nrar€qsm€nt. fle€.nan and Coftpany San<br />
Fra.cisco. Ch.2.<br />
llolgan - Davi€s, A.n. (1980).<br />
t71 - t1t.<br />
Tla€locattng crocodlles. Oryx 15 (4)t<br />
l$hande, J.N.8. (1986). sbb.ls of th6 nile clocodilo tn lblaut.<br />
A r€polt to tia Depaltnent of tbtioral parks<br />
and tlildlif..<br />
pool€y, A.c. (1980a). clocodil. rss6atdr in llaputaland.<br />
Inr Srston, !l.t!. ard Coop6!, k.g. (g*). S trOiea<br />
on ti6 €cology of lt publand. 29t - 299.<br />
Pooley, A.C. (1980b). Ih. dBcline of c.ocodite6 in AFlica.<br />
rlelj_r_c_ g!!] BuIr. rl (e-e!'!10)3 er - 94.<br />
S t!ov6!, P.tt.<br />
Yilllar6on, C.<br />
.1989). O|,arE{!. Ssga! CoDporatlon Ltmited, Crocodll€<br />
clutch aacord€. Typ€scrip L<br />
ANO pAYiE, 1.r.3.a. (19?8). An tnt odrction tE aninal<br />
husbandry ln th. ttopr,6. fld ed.<br />
Longran Croup, Liott d, London. Ch.ll<br />
13
l4<br />
GROWIII AND SURVTVAL OF Crocdyhs acuas<br />
IN SOUTII FI,ORIDA" USA<br />
Paul E. Moler<br />
Wildlife Research Lab. 4005 South Main St.<br />
Gailesvile Florid,a 32601, USA<br />
C.L. Abercrombie<br />
Wofford College, Spartanburg,<br />
South Carolina 29303. USA<br />
A tolal of 391 crocodiles were tagged on Key IJrgo, Florida, USA betweer 1978<br />
and 1991. Ttvo hundred of ttrese were recaptured a total of 530 tirres. All but 2 of<br />
these recaptures were of low'n-age animals. Hatchling survival varied markedly<br />
from year to year, being lon er in years of low rainfall. Estimated first yeat survival<br />
for the period 1979-1988 was m.4%, but age-specific survival increased to 64.97o in<br />
tle second year. Annual survival of American crocodiles nore than 5 years of age<br />
excee.ds 80Vo and may approach 100%. Hatchlings grow rapidly for the first four<br />
nonths, but then growth essentially stops with the advent of cooler winter<br />
temperatur€s iD early December, Some fudividuals may reach minimun<br />
reproductive size by an age of 8-10 years, but it is not knovn whetler crocodiles are<br />
repr,oductively competett at this age.
GroMh rates and lood conversion efficiency in Nite crocodile<br />
Benjamin Morpurgo<br />
halchlings fed on pellelized food.<br />
Center For Reproduction<br />
of Endangered<br />
Specles<br />
San Diego, CA, 92112<br />
USA<br />
Afler five years ol rearing Nile crocodile hatchlings in lhe<br />
Gan-Shmuel <strong>Crocodile</strong> Farm, tsrael, a new dietary reg;men was<br />
examined. Until 1990, the diet of lhe crocodites, from ;atching to<br />
sfaughtering al age 24 monlhs, was composed o, two ingredients.<br />
For the first lO months - ground meat with supplements. From tO -<br />
24 months dead and live chicks and ,ish were fed. ln strivtng for a<br />
more commercial diet, due to the increase in number o, hatchlings,<br />
lhe use ot pelletized tood was examined.<br />
A cohort ot g-day old Nile crocodiles was divided into three<br />
equal groups ot 21 animals. Each group was fed on a difrerent tatio<br />
of high protein pellets and ground meat (g}%_70%t SOo/"_SO%t 7Oo/._<br />
30o/o). During the seven months of lhe experiment, all the crocodites<br />
were weighed and measured at monlhly intervals. Food intaKe was<br />
recorded .<br />
During the 7 months of lhe experiment, the crocodiles grew an<br />
average of 32.4 cm, and weight increased by 711|,45 g. These resutrs<br />
are be er than those recorded the year before (S9O g: 2g.2 cmr.<br />
No signilicant differences were found in growth among the<br />
groups. There was a signiticant ditference in lhe variance between<br />
the groups. The variance was smaller as lhe pellet portion of the<br />
diet was increased.<br />
15
Age comPosition of<br />
captive female Nile<br />
particiPalionof<br />
young females<br />
Beniamin MorPur9o<br />
Center For Reproduction of Endangered Species<br />
San Diego, CA' 92112<br />
USA<br />
crocodiles and the ellect on<br />
in reproduclive activity<br />
During two years, the question of the influence ol adult lemale<br />
;;.;;." on reproductive activity ol immalure females was. studied'<br />
Twelve adult males were divlded into Mo equal groups and housed in<br />
a |.ectungular, 8OO m2 pond. In lhe first group' the female population<br />
was composed ol 45 individuals' 25 were 9-lo years old' and 20<br />
were 6 years old. ln tne second group' the population was composed<br />
ol 45, 6 Year-old lemales'<br />
Euring the lirst year of lhe lwo-year study' the young females in lhe<br />
mixedandthemonosizegroupsdidnotparticipateinreproductive<br />
activity, although courtship was made by the males in the monoslze<br />
pond. In the second year, in the mixed age lemale population only the<br />
adult lemales mated ln the 6 year'old female group' during the<br />
second year,7 out ol 45 maled during the reproductive season'<br />
It appears ihat the presence of adult females inhibits mating<br />
acriviiy Uy the younger females In the absence ot adult lemales'<br />
young lemales show some reproductive activity'
Pond structure; The relation to hierarchy and reproductive activity<br />
Beniamin Morpurgo<br />
Center For Reproduction<br />
of<br />
San Diego, CA, 921'12<br />
USA<br />
in male captive Nile crocodiles.<br />
Endangered Species<br />
Pond structure for reproductive herd is a very important ingredient<br />
in crocodile tarming, especially in areas where there is no wild<br />
population, such as in lsrael, where the present study was made.<br />
Twelve male Nile crocodiles were divided into lwo equal groups. The<br />
6 crocodiles in each group were 9-10 year-old, and their sizes were<br />
3.15 to 3.50 m.<br />
The first group was housed with 35, 5-9 year-otd temales, in a gOO<br />
m2 enclosure, 60% ol its area a rectangular shaped pond. The secono<br />
group was housed with 35, 5-9 year-old lemales, in a 8OO m2<br />
enclosure, 60% ol its area an irregularly shaped pond.<br />
In the reclangular pond, only one male was {ully functional, two<br />
others mated only when lhe dominant male was oulside the water,<br />
and the other three did not exhibit any reproductive activity<br />
throughout the season. OI 35 females in the pond, only S mated. In<br />
the irregularly shaped pond, all six males maled, each one In a<br />
lerritory he created around a bay. At teast 29 lemales mated during<br />
the season.<br />
The conclusion of this two-year study is that unless the populalion<br />
is one male and several females in a rectangular pond, irregularly<br />
shaped ponds are preferred.<br />
t'7
18<br />
Ndr theas tern Belize<br />
Department of<br />
Sur iname t<br />
P.O.B, 9212,<br />
Pau I E. Oubo l€ L<br />
Zoology' Anton de Kom Universitv of<br />
Paramaribo'<br />
Strriname.<br />
I NTROOUCT I ON<br />
Althouqh several authors reported on crocodiles of Belize<br />
(NeilI & Allenr196l; Potnell, 1971; AbPrcrombie et ar"<br />
19BO' 1942), the northeBstern Part of the countrv kas<br />
almost conpletelv omitted bv thPse earlier survevs' This<br />
is curious since this part includes numerous larqer and<br />
soaller geaside and inland lagoons Nhich seem to ProvrdE<br />
good potential habitat for crocodiles' A possible reason<br />
is the inacces6ibilitv of this area which has few roads'<br />
Between 26 April and 30 May 1991 (drv seasonl a survev<br />
took place in and around the Shipstern Nature RPserve'<br />
Both Et:9!glbl!l]e noreletii and Crocodv lus q!1$ll9 were<br />
found in the area. The status of both species worldwidP<br />
is bad, sothat any report in ttrerr<br />
dietributictn range sofar uriPxamined is of i Portance-<br />
ME'] HODS<br />
Creeks, lagoons and pond-- to be investigated were<br />
selected {rom maps' airphcjtographs and Landsat sateltite<br />
images. Criteria used in selPcting were Io'al<br />
reports crocodi I e siqhtings ' habi tat featurEs<br />
(heteroqenuity' depth ot vrater' Ntnd direction' etc') and
accesslbility. The last criteriutn excluded several<br />
lnteresting inland lagoons which could only be reached<br />
through a labyrinth of mengrove marsheE or travellinq a<br />
lonq distance overland on {oot.<br />
In selected arear surveys were carried out during<br />
the day and the night, DLrring the night crocodiles Nere<br />
epotted by eyeshine usinq a handheld 12 V spotlight or<br />
4rS v halogen headtight. MoE't surveys. were carried out by<br />
canoe, some by motorboatg powered by an outboard motor,<br />
STUDY AREA<br />
The northeastern part of Be!.ize i5 the Yuceran<br />
tlatJorm and mainly :oneists of beds of limestoanE<br />
covered by subtrupical hardwood forests' wet savanna< rnd<br />
lagoons, l'lost aquatic habitats are ealine, salinitieq<br />
ranging from 6 to 33 promille , Lagoons (4,7,8'lO and 1l<br />
in fig. l and tab. 1) are usuelly very shallow and<br />
surrounded by red mangrove (Rhizoohora !E!l-S-!€-). Most df<br />
these are directly or indirectly connected to the sea' so<br />
not subject to dryinq during the dry season. Cenotes<br />
(sinkholes) (5 and 6 in fi9' l end tab. l) are usuallv<br />
much deeper. Creeks connecting lagoons are uEually deeper<br />
than the lagoons itself' ranqinq to more than 2 m in some<br />
localities. John PileE Creek, Wakaxkav and Dhacan Chac<br />
l'lol (1,2 and 3 in fi9, l and tab, 1) are less saline (6<br />
to 11 Dromille).<br />
19
20<br />
fIESULTS<br />
An ov€rview of habitat features oi the different<br />
localities is presented j.n table 1.<br />
Re5ults of the surveys ar_e Presented in table 2'<br />
Crocodvlus moreletii is PrPsent in the less saljne<br />
habitats, John Piles Creekr ChaEan Chac l'lol and<br />
corozalito Lagoons, In all th?_ee localities Juveniles<br />
l@.4 - @.7 m) and adults were seen (it is supposed trhat<br />
C. moreletii can reproduce at a size of 1'5 m)'<br />
CrocodvluE qg]Ilg5 sEen were all in the more 5aline<br />
habitatE. The crocodile eeen in Corozalito Crtek was<br />
quite hear to the q1 moreletii PoPulation in the lagoons.<br />
This gpecinen was dark in coloration although it had the<br />
very slender snout of a qr acutus' It i5 treated here as<br />
unidenti{ied. Of the four q. acutus actually seen two<br />
,rere 6ubadult6, two juvenj 1eE. These juveniles were Jound<br />
in Barracouta Pondr a de|?p lagoon with relatively high<br />
beacheg all around. A nestr presumeble trom c. acutust<br />
was lound on the northern side of the lagoon (the eggs<br />
lrere not counted in order not to disturb the nest too<br />
nuch ) .<br />
DISCUSSIT]N<br />
ln Belize a moratorium on the killinq oJ crocod.ilts was<br />
proclaimed tn 19Sl (Abercrombie et al ' 19t12) ' Locar<br />
people were of the opinion th.at sinEe that time tttP<br />
nu6ber of crocodiles had increased enormouElyr becauEe<br />
crocodileE Nere no lottger hunted for 'their skin. Stories
of areas |4ith large numbers ol crocodiles or of very<br />
large specimens are widestrread. Dur.ing this survey onfy<br />
small numbers ot g:,noreltllijl b,ere encountered and even<br />
sttaller numbers of q: Cllrtus. Some informants told me<br />
that every crocodile seen by the locals is kil!ed as<br />
verrnin and it was sometinreE' even posEj.ble to sell the<br />
Bkin to foreigners. This makes it unlikety that (ne<br />
droratorium will have any effect in HeIl frequented areas.<br />
In remote areas it could be effective since peoolp dre<br />
not lnclined to take the trouble to 9o there for illegal<br />
crocodile huntingi they only kilt the crocodileg<br />
encountered accidental ly while occupied in other<br />
actj.vitiee (usually fishing). ThiE meens that crocodile<br />
populatlons near human occupation can only be protected<br />
by includtng them in nature or other protecred<br />
[jnfortunately al I crocodi Ie poPulations<br />
encountered in NE Eelize were outside the Shipstern<br />
Nature Reserve. To incl\rde two of the C. moreletii<br />
populatlons (Chacan Chac t'tol and Corozol.ito) and the C.<br />
acutus breeding cite (Barracouta pond) in some sort of<br />
regerve (poE5j.bly enlarging the Shipstern Nature Reserve)<br />
could be a good solution to this Drobtem.<br />
21<br />
The statue of L g_g!4.!tE"<br />
on the maintand of Belrze<br />
has beeh extrefiely bad. powell (1971) reportecl q: Bculu5<br />
to be rare oo the mainland, somewhat ,nore common on the<br />
otfehor€ i5IandE. Abercrohbie et at. (f9AO, f9A2)<br />
encounter€d only qs morel€,tii no C. acutus durtng thalr
22<br />
alnland surveys. On the basis of these data King et al'<br />
(1982) conctuded that E: agglg-a i5 almogt absPnt on the<br />
mainland. Zisman (1989) mentioned the occurrence of both<br />
C, moreletii and Q: 4!glg-9 in the Northern and SoLrthern<br />
Lagoons' but breeding only occured in two areas of the<br />
keys. This nakeg the finding of several eubadLrlt and<br />
juvenile specimens of E: i!q4!5. in the NE interest1ng'<br />
However, apart trom Barracouta Pond' the "poPuIation"<br />
seems widely scattered. Even when given JuIl protectiont<br />
the area could only harbor a small poPLrlation'<br />
Most ponds and lagoons are very smal I ' shal lo$! and<br />
isolated from other waterbodies' OnIv the Shipstern<br />
Laqoon and borderinq lagoons prowicJe an extenslve area'<br />
UnJortunately these lagoon_' are not very fertile and nost<br />
lack any signif.icant amount of fish (pers' obs' )<br />
Nothwithstanding this pessimism' protection of the<br />
Barracouta Pond area, tncluding th€ adjoininq seacoast'<br />
could helP the survival of the American croEodile rn<br />
Bel ize.<br />
C. moreletii and q: iEutus are sympatric in Belize'<br />
tn most publications (NeiI' 1971; Alvarez del Toro' 1974;<br />
Groolnbridge, 79a7 ) c' Doreletii is supposed to be<br />
conlined to {reshwater habitats' This study showet ae wag<br />
already reported bv Abercrombie et al ' (19A2] ' that !:<br />
moreletii populatione do occlrr in brackish water' the<br />
ueual habitat of q.= es!-ggE ' Medem (1981) mentioned the<br />
increase ol Caiman crosodilus in brackigh h'Fi!_ts of
sone riwers of Colombia {ollowino the extinction of ,er<br />
acutus. It is likely that Eomething sinilar has happened<br />
in Belize: C, moreletii resistant to hunting due<br />
tn i +q .nnnl Fw and<br />
reproduction at a younqer age. AJter the erteflninalion of<br />
q: acutuE rt eraE able to clipprse to brackish habitats<br />
previouBly occrlpied by C: e-c-g!Jl-s-.<br />
AC KNoUlLl. DG E llE r,J T S<br />
This study waq initiated b/ the lnternational Tropical<br />
Conservation Foundation and frnancially stlpported by the<br />
Van Tienhoven Stichting. t I ike to tharrk Jorqe Verde '<br />
Auriol Samos dnd Benito Flc,res for the inform.ltion thet<br />
presented on the Iocal crotodi le si tuation, and Jao ,:nd<br />
Tineke Meer.nan for their 9€neral support.<br />
ABS TRACT<br />
Surveys in LaQoons' cenote_- and creeks o1 Northeastern<br />
Eelize reveared several sm.all PoPUlations o{ bq/,odv lu:-.:<br />
moreletii and some specineo'i o{ CrocodvlLrs acutus. All !l<br />
noreletii populations were in the less saline habitats.<br />
Reproduction ot E: {c-q!rg Eeened to occur in the arpi of<br />
Barracouta Pond,
u<br />
REFE RENCES<br />
Abercrornbip' C.L. ' Davidson' D. ' Hope, C.A' & Scott' D't''<br />
(l9AO). Status of horelet'e crocodile Crocodvlus<br />
noreleti in Belize. B-!qt: Conserv. ' !Z! 1o3 - l3'<br />
Abercrombie, C.L. ' HoPe' C A. ' Holnes' .t 'm. ' Scott' D' &<br />
Lane' J.E. (1942). tnvestiqatrons into the st:tus of<br />
more tet's crocodile {CrocodYlus noreletii)<br />
BeIize' 198O. Proq. 5th l'Jork lleet. Croc. Soecr' 12 -<br />
16 Auougt leaq, qs-i!r? 5v i I1..e,' USA' luq! 8!-b!. N,cr4<br />
qe!' 11 - 30 .<br />
AIvarez del loro' l'1. ( 1974 ) . Loe -C-rq.sq|)-!-r-q de<br />
A.C,, hexico, D.F. ' lostituto mexicano de<br />
Natural es Renov ab I es.<br />
Croombridqe' B, (1987). The DiEtribution and Status of<br />
lr,orld CrocodiIianE. In uiildlite !q! cs€llefl!:<br />
<strong>Crocodile</strong>s and AtIioalolg, ed5. G.J.t^i' Webb' S'c'<br />
l'1anoIis. & P.J. t'Jhitehead. Surrev Beattv' ChipPrtrg<br />
Norton'PP.9-21.<br />
Kinq, F.W.' Campbell ' H.trJ. & f'1oler, P.E. (1942)' Rewll.'w<br />
of the status of the American crocodile' Proc' 5th<br />
Ulork l'1eet. Croc. Soec', 12-16 Auoust 1-?-gl'<br />
Gainesville, USA. IIJCN PubI. NC!4 gCI:! Aa - 98'<br />
Medem' F. (1941). L=gE Crocedl! lle de Sur America, !, Los<br />
Crocodvlia glq Colombig. Colciencias' BogotA'<br />
NeilI, t'i.T. (1971). l-b-C .laEt of llbg rulina reFtiles'<br />
Columbia Univ. Pressr Ne!'r York'
Neill' W.T' & Allen' E'R' (1951) ' Further studies on the<br />
herpetotogY of Br i t i5t\ Honduras'<br />
Heroetolooica' !2, 37 - 52'<br />
Potaell, J.H. (1971)' The status of crocodilianE in the<br />
United States' mexrco' Central America' and the t'Jeet<br />
25<br />
Indies. Plgf. 1Et Work .IESL' Croc' SDec" l5 -17<br />
March 1971' New York' IUCN Publ ' New ser' ' 2' 72 -<br />
e2.<br />
Zisman' S. (19S9)' The dir€?ctorY of protected areas and<br />
sites of nature cr,nst:rvation interest in BeItze'<br />
Dep. Geographv' Univ' Edinburgh' Occ' Publ' 1o'
26<br />
Figure 1. Map of the stlrdy area.<br />
specimens seen at each<br />
indicated with each si9n.<br />
The number ot<br />
loca I ity i5<br />
Tab le 1 Habitat features of al I waterbodies<br />
Eurveyed in Northeastern Belize, Specimens<br />
from locality B t^,ere sern and identified<br />
by local people,<br />
Crocodil ians seen<br />
in Nor theastern<br />
I oca 1i ty B were<br />
I ocal peop I e.<br />
at di.flerent we terbodies<br />
Bel ize. Spesimens f rorn<br />
6een and identified by
. r;<br />
\<br />
q\<br />
:i<br />
€ C<br />
_ta-<br />
,. E?ndi<br />
q<br />
:<br />
;<br />
'? --<br />
4d<br />
9:o<br />
27<br />
s!.flI:<br />
i3 E.5<br />
o o.-! o<br />
or:E{,<br />
ox9;o<br />
.i90:6<br />
zdd: i<br />
El .oo><br />
>i<br />
Et! i
28<br />
Locrlitt<br />
2,<br />
5,<br />
lrEr.9r<br />
depth l.)<br />
Join Pil?6 l.?<br />
C.e.l<br />
lrlir||Y<br />
0.1<br />
Ch.r.n Ci.t 0.5<br />
Itol<br />
Irr..routr<br />
Pond<br />
o.!<br />
5, l.rree light 0'5<br />
C€note<br />
6. Sirt?n.jt<br />
Cmot!<br />
7. L.goons<br />
Shipst.rn<br />
lorest<br />
0. L.goons<br />
ShiPstrrn<br />
deeP<br />
0.1<br />
0.1<br />
t, Corol.lito 0'l<br />
Cr?sl<br />
10, Cororrlito l'0<br />
[4oon5<br />
ll. Ship5trrn 0.5<br />
L.9oon<br />
12. llorthern<br />
5e.<br />
Co.st<br />
TiblE l,<br />
ll.ri.u.<br />
dlptn 1.,<br />
)3<br />
0.8<br />
>2<br />
)l<br />
d3?D<br />
0,3<br />
t.0<br />
0,7<br />
l,l<br />
1.2<br />
lidtll<br />
la,<br />
20<br />
300<br />
t00<br />
t500<br />
l?0<br />
100<br />
100<br />
l.tar collr|r S.lioitt Shor! v.gtt.tior Se'ri!5 Pr'*nt<br />
trro.ill!l<br />
9rlln<br />
9a?.n!5n<br />
9rl?nrsn<br />
rllrr<br />
broffish<br />
ht!|ni3lr<br />
(lPar<br />
6-lt<br />
l0<br />
7<br />
2l<br />
5.ltt<br />
5rlt,<br />
srltt<br />
rrd $nqrova/<br />
hardtood<br />
!r455<br />
!ril5<br />
red aangroll/<br />
barfilod<br />
rad rangrovl<br />
red |.ngrova<br />
r€d r.nqroY.<br />
C..lr.lttii<br />
C..o.rlrtii<br />
C. a(utls<br />
C. atutug<br />
300 (har !.lty red Dngrovr {[. ecutusl<br />
?00<br />
2000<br />
brornish<br />
tl!ir<br />
(hrr<br />
br.rlisn<br />
brr.liri<br />
h.rdrood<br />
rcd a r0role,<br />
rEd fingrovl<br />
hrrdmod<br />
lhbrt.t t?.turt5 ot rll r.t!rbodiee rurY"'d.in lortnlr5t'rn B'lrr''<br />
;;.;;";;;; ioirtitr s ..re 'em 'nd idlntilr€d ht loc'l p'oprr'<br />
unidlttili!d<br />
unid?ntiJi.d<br />
C..orll.tia<br />
mideniilied
Lot.liit St ci.! ftl|!.t ol splli|trt<br />
a(t!.llt 3!€n<br />
lh.trtln hrrcl.ts incl,<br />
llnidlnlirild 3D!(i..n51.<br />
l. JolD lilE Ct.el<br />
2. bl.tt.,<br />
3, Ch!.n Cln. llol<br />
l, g.rr.Gout. Potd<br />
5, lrrr4 Bilht ClnltP<br />
6. Srrtlnair Ceilt?<br />
7. 1.900n3 Siitstlrn<br />
torr5t<br />
g. lrqooni Shipstern<br />
9. Cotor.ltto Ct!!l<br />
10. Corol.lito Lrloon<br />
ll Shig.tlrn L.goon<br />
U lbrtlErn Srr Cortt<br />
t..ortt.lii<br />
C. rot.htii<br />
C..rutll5<br />
B. itrtuB<br />
||nidlttiJi!d<br />
lC. rcutusl<br />
unid.utili!d<br />
C, |ot.l.lii<br />
unidlttiti.d<br />
2t6)<br />
9u0l<br />
3<br />
I<br />
0<br />
0ll)<br />
0<br />
0lll<br />
6t9l<br />
0<br />
0trl<br />
l.bl. 2. CrDcodili.trs s..n rt dilf'rtnl r'tlrbodi$ in lDitlE$tlrn lelir!'<br />
'--'- -'<br />
im.ire* lro. lo(.litt I rer! t.!n .l|d idFliti'd bt loc'l ,.opl!'<br />
ourh.l ol S9tcirtn3 6irl rrn!'<br />
3!ln bt lo(alt<br />
|tnt<br />
5<br />
I<br />
2<br />
l<br />
I<br />
I<br />
29<br />
0.5-1.9<br />
0.7-2.3<br />
0.6-1.5<br />
1.2-l.t<br />
1.5<br />
0.1-1.5
30<br />
AMERICAN ALLIGATOR (AWgotq mississippiensis) CLUTCH<br />
VIABILITY FROM SEVEN STUDY AREAS IN FI.ORIDA" USA<br />
H. Franklin Percival Greg R. Masson, Ketrnetl G, Rice* and<br />
Allau R.<br />
Woodward<br />
Florida Cooperative Fish and Wildlife Research Unit<br />
University of Florida, 117 Newins-Ziegler Hall,<br />
Gainewille, Florida 32611-0307.<br />
*Presenting<br />
the paper<br />
Seven study areas in three Florida drainages were considered in this four year study.<br />
These were the Otlawaha River drainage (I-akes Apopka and Griffin); St. Johns<br />
River drainage (Lakes George and Jessup); and Okeechobee/Everglades system (two<br />
Lake Okeechobee areas and Conservation Areas 2A and 3A), Collection efforts<br />
totalled 1215 nests yielding L259 clurches or 52515 alligator eggs (meatr clutch size =<br />
43.2). A mean hatch rate of 0.592 produced 23,100 hatchlings. Preliminary analyses<br />
itrdicate significant differences iu viability rate (overall x = 0.488) among drainages,<br />
among lakes and within lakes by year. The OkeechobeeTEverglades system sho$/s the<br />
highest viability rate of 0.596 over the four years, followed by the St. Johns drainage<br />
with 0.46 and the Oklawaha river drainage with a 0.206 viability rate. Iike Apopka<br />
has continually had the lowest viability rate (x = 0.198), while tle Conservation Area<br />
maintained the highest (x = 0.657). Each study area demonshated a great deal of<br />
annual variability in viability. More than 2/3 of the enbryonic nortality occurred<br />
prior to the 20th day of incubatior. Furthermore, 807" of this category is<br />
attnibutable to zygote mortality (in utero mortatty). h fact 40Vo of all embryonic<br />
deaths occurred prior to ovipositiou.
UTILIZATION OF CROCODILE RESOURCE FOR RURAL DEVEIOPMENT<br />
PROGRAMME IN BANGI,q,DESH<br />
M.M. Rahman<br />
Research Ofricer (Wildlife Section)<br />
Bangladesh Forest Research lostitute<br />
GPO Bor - 273, Chittagong - 4000,<br />
Bangladesh<br />
A 10-year research sho*'s that three species of ctocodile had been a pote[tial<br />
resource for the illegal ta{ers as its products are pdzed in th€ national and world<br />
market The res€arch also itrdicates that a large population of the animal was killed<br />
by the illegal skin traders about 30 years ago in the coutrtry. Consquently, crocodiles<br />
were becomiag so rare iu Bangladesh,<br />
A sinall populatiou of crocodile was located in the padma/tamuna river and<br />
estuarine a,reas-of the country. A species of marsh croocdiile (Crocdylw plutris)<br />
has been already disappeared ftom the natural habitat but the animal:t l exists in<br />
captive condition ooly iD the country.<br />
The status of tle atrinal breeding aspects and distribution so far studied are<br />
presented itr this paper. The possibilities of rehabilitating this animal in other areas<br />
of Bangladesh depending ou the food availability have also b€etr discuss€d. It also<br />
suggest for the utilization of crocodile resource in rural dev€lopment prograDme.<br />
31
c o N sERvAlol;i1iluPiiJ,:fi:fi oD rrEs,N rH E<br />
ABSTRACT<br />
Or. R. J. Rao<br />
School ol Zoology<br />
tl?iJi'l?,i'rt'' (,'n P) rNDr^<br />
1-lrc Ctoco(Iilc l'roJect ts onc dJfthc strcccssJirt Il,il'lli/c Projccts iIt ltclia The<br />
success oi tiris Project is moinlg due to the elforts token bg indiuidudl States in<br />
the ccuntry, Tlrc <strong>Crocodile</strong>s h tne M.rdhga Praclesh State ho:ue receloed qctive<br />
f,otcction-tn<br />
sPecl(lllg created Prctected areqs' A total oJ Crococlile<br />
.tlvee<br />
sonchr(rries nolnelg, Natlonol Chambol Sanctuary' Son Gl'ariol SanctLrcrrg' c"ncl<br />
t:an Gll(.ri(ri Sancfuqry lr.rue been declcired where nranogemettt programmes<br />
\auebeettta|cenJorconservatlonoJGhc|:icLldndMugger.TheNCsisoneoJthe<br />
best lobitatJbr Crococllles in In'lto' As pects relatecl to conseruotiotr nv ragemetrt<br />
o-f Crocodilcsin these Scnctucrl€s ore cliscussed h tlrls pdper RecetilA' therc<br />
trc seDercrl rePortson nuisqnce Mtt99 cr tn tlrcstc:te' Measures ltdDe been talrcn<br />
tc rehabliit.te these nlugg€rs, Results or ue no|litoring studies indicate tlrat t|re<br />
con:tervqtlotr progr(lmtnes nove d' positioe ifllPcct o't tlrc poptLlcLLial]s of<br />
CrocoCiles in t,.e il{aclhya Pra'leslr'
&EodrEtiql<br />
In India three species of crocodj-Les ocolrr. They are c haria-I<br />
( Gavia-ljs gangeticus), nugger (Crocodylus pa.Lustris ) and sa-Itwater<br />
crocodile (Crocody.lu,s porosus). Due to codnercial hunlilrg for ahe<br />
Iuxury leather trade, the j.dtroducLion to nylon gi,II netLing and habitat<br />
loss popu-lalions of crocodiLe species uere greatly depleted (H.R.Bustard<br />
in FAO, 1974). Al.1 the three Indian crocodj.Iian species aie t lsted<br />
as 'eodangered,<br />
in the IUCN Red Data Book (].972). They have also<br />
been lisLed in Appendix I of CITES (ConvenLion on InternaLional Trade<br />
in Endangered species of Wild Fauna & Flora). Recognising their endangered<br />
status, the Government of India ha,s given proteclion to the crocoaliles<br />
by including them in the Schedule I of the Indian Wildlj.fe ( plptecticn )<br />
Acf of 1972. A massive rehabi.IitaLiqr programme for crocoali-Ies was<br />
started by the covernment of India during l9?5 under <strong>Crocodile</strong> projec!<br />
(Rao, 1985, singh gq al 1984; C houdhury & Choudhury, 1986). Different<br />
state Govemments have adopted thi.s programme. covernnert of M.p.<br />
a-IEo started crocodil"e ccnservaliod projects jn 1978. In Madhya pradesh,<br />
tl'o species of crocodiles - gharial and nugger occur. This paper<br />
highlights the crocodile cooservation project in Madhya pradeeh.<br />
<strong>Crocodile</strong> Prcrject in U -P.<br />
The gladhya project covernment has undertaken rehabiLitatioi<br />
programme for the highLy endangered crocodile specj.es _ the gharial<br />
under the Crocodi.Ie Ccnservation project. The important ghariat habitats<br />
rrere identilied and given protecti.on by declaring them a.s sancEuarres.
34<br />
<strong>Crocodile</strong>s are afso being protected in Ci!:erent sanctllaries and National<br />
Parks of the StaEe. Rehabilitation of cLocodi-Ies ',tas stalted during<br />
I9?8 by adopLing :he rgrow and releaser cechnique suggested by Bustard<br />
(FAo, 1975). T hj.s technique is aimed a! ltild laid eqg collection for<br />
hatching and rel.easing oi the juvenites ioto protected habitats after<br />
seveaal years of captive rearinq to glve the$ a better chance of surviva_l'<br />
Monitoring of the released crocodile6 in different sanctuaries has been<br />
taken up to evafuale the success of the rehabi-litation programmeg'<br />
<strong>Crocodile</strong> s-rctuari.es in n-P-<br />
The Madhya Praalesh Government has declared three sanctuaries<br />
for the conservaticd of crocodiles. They are (Fig. I) :_<br />
l.<br />
7<br />
National Chambal SanctuarY<br />
son Gharial Sanctuary<br />
Ken Gharial Sanctuary.<br />
In these sanctuaries managemeol<br />
for the cooservalioo of the gharial-<br />
Ndiqral Chambal Sancba4'<br />
program nes emphasised<br />
The National Chamba-I SanctuarY (a tri state - Iv!'P-' U'P''<br />
Raj. - sanctuary ) is one of the najor crocodilian sanctuaries id rndia'<br />
spedally created during Lg78-'79 for the conservaEion management of<br />
gharials did ocher wild aninals. The sanctuary extends over the chambal'<br />
river from Ja!,/ahar Sagar Dam to Kota barrage and after a gap of
13 kms free zone/ irom Keshoraipatan (Raj.) through Pa-li to Pachhnada<br />
(U.P.) where Kun!./ari, ?ahuj and Sindh rivers form a confluence vith<br />
the Yamuna ri.ver. The tota-L lenqth of lhe r.iver insrde tne Sanctuary<br />
is about 600 km. The Hidth of the river that is included insi.de the<br />
Sanctuary is 1000m trom either bank in Rajasthan and l,ladhya Pradesh<br />
whiLe Uttar Pradesh has a greater width totaling to an area of 635 sq.km.<br />
(Singh, 1985). GeographicalLy, the Sanctua.l lies betlreen Lat.25'23'N<br />
and 26'52tN and Lonq.76"2E'E aod 79'01tE.<br />
Sanctuarv Manaqement<br />
tha NaLicnal chanbal sancLuary is managed by the Forest<br />
Departments ( wildlife L'ing ) of Rajasthan, Madhya Pradesh and Utlar Praalesh.<br />
The Sancb.ra r head quarters of M.P., U.P. add Rajasthan are at Deori,<br />
Dist. Morer r; Agra and Kota, respecLively. Stopping of fishiog acLivrty /<br />
naintaining ful-I protecLion from poaching, extending protectjoo to habilal<br />
and rehabi-Litatsion of gharial under rgro!, and relea3er scheme are<br />
the nanagenent strategies adopted in the NaLionaf Chambal Sanctuary.<br />
The protectioo and tiel.d stalf work under the adminGtration control<br />
of the Chief l4lildlife warden of their respective States. The management<br />
staff posted alL along lhe Chamba.l river keep a regu.Lar vigil to stop<br />
any il-legal f*hing and poaching of gharia-l and other wi-Idlife. In<br />
additicn to protecLion, the field staff codduct crocodj-Le and other<br />
wildlife surveys and a-lso locace tharlal nests in the Sanctuary - The<br />
gharia.L eggs are collected by U.P. and fl.P. Forest DepartmenE for<br />
rehabilitaLion programme dnder tne jrocodile Project. Charral e99s<br />
were afso collected by the Orissa Forest Depaltment from the NaLional<br />
Cha.nbaf SancEuary during 1980-82.<br />
35
JO<br />
GhariaL RehabiLltaticn<br />
RehabdieaLico of gharial has been taken up in the NalionaL<br />
Chamba-I Sanclu3ry fFom 1978. So far/ a tota.l of 1,762 captive reared<br />
ghariaL at Kukrail crocodil-e rehabilitaCion centle, Lucknov, U.p . ,<br />
have been reLeased jn the Chambal river by Uttar Pradesh Forest<br />
Department (Rao, 1988; Hussain/ 1991). During February 1989, Madhya<br />
Pradesh Forest Department had released 5 capLive reared ghariaL at<br />
Deori GhariaL Rearing Centre, Morena, M.P. i.n the Chanbal ri.ver.<br />
Young qharia-I from Che Nafj.cna-l Chambal Sancbrary have aLso been<br />
released in Ken and Son gharj.al- sanctuaries of the State.<br />
SEatus of Ghari.al in NCS<br />
Accordirq to Singh (1985), the gharia-l populaLion in Chambal<br />
(4m kn) during 1978 was esLinated to be around 107 $rifh a sighting<br />
density of O.29 per kn. Singh a-lso repoEted the gharial population<br />
in the ChambaL river during 1983-84 and 1984-85 as 451 and 605 wilh<br />
a density of l.O8lkm and 1.42lkm 7 respectively. Accordiog to Rao<br />
(1988), sighting populalion of gharia.I in chambal river during 1985-86<br />
was 618 and during 198?-88 the nuft ber was 804. The populaLion density<br />
was eslinatd to be 1.6/kn in 1985-86 and I.89/kn in 1987-88. The<br />
population estimates revealed Ehal lhe gharia.l popul.atiod in the Chambal<br />
river has been recovering over the past decade from an earlier decLining<br />
statLrs. The j..rcrease in density. of ghariaL from 0.26lkn in 19?8 to<br />
1.89/km in 1934 indicat€ lhat the gharial. popuLati.on in Chambaf is<br />
in a recovering -ohase (Rao, 1988).
Status of Mugger in NCS<br />
The mugger (crocodylus pa-Lustli.s), a.lso knoirn marsh<br />
crocodj-Ie/ i.s presen!, allhowh Less i.n number in lhe Chambal river'<br />
They m oetty prefer rocky isLets for basking and they nest on sand<br />
banks covered !,tith rocks and bushes. According to 1984 estimates<br />
(sinqh, 1985), around 12 nugger nests have been located in lhe chalnbal<br />
river. Mugger ne€ts have been Located very clase to thariaL colonial<br />
nesting sites. Durjng Apri-l 1984/ a total nunber of 28 mugger that<br />
had originated from eggs collecled from the chambaf river were release'l<br />
i.n the NatiooaL ChambaL sanctuary (Si.ngh, 1985). one nest of inugger<br />
eas coUecteal by the t4adhya Pradesh Forest Department for captive<br />
rearirg programne durinq 1987. to avoid any possibLe effecc on gfrarial<br />
populatim sjngh (1985) reported that mugger in a gharial' sanctuary<br />
be not supplemented through rgro\t and release prcgramme!.<br />
Crocodjle Captive Rearing Proqranme a! NcS<br />
Uflder the crocodile tehabiLitation proqramne, crocodi_Ie captive<br />
reari.ng centre has been establGhed at village Deori, District Morena'<br />
I'1.P. during L980. Searches sere made in lhe chambal river to focate<br />
ghariat nests. Durinq 1981, a singfe nest of gharial (35 eggs) as<br />
located at Baroi.i nesting sile ancl the eggs were ttansferred to Deori<br />
for arlificia] incubation. From 198f onl/ards, every year (exc€Pt 198-l<br />
and 1986) gharial eggs are collected ior harchery incubaLi.on (See Table I)'<br />
ltatchlings elnergeal from the eggs !,tere calefullY reared at the Deori<br />
charial. Rearing centre ( DGRC )<br />
37<br />
(Rao, 1986. nao and Sharmar 1986).
38<br />
Resufts of the<br />
Table l. Some<br />
Ken rivers (see<br />
captive rearing<br />
Iab.Le I ).<br />
programme a!<br />
gharial have<br />
During 1987, a clutch of Tugger<br />
the Chambal river. The eggs were hatched at<br />
hatchlings are being reared at the Centre<br />
to release the muggers in protected aaeas in the<br />
Scrt Gheial Salr(fraE\/<br />
Natural poprj-lalion of gharial<br />
be around 1I of different sr.zes.<br />
DGRC are given in the<br />
been re-Leased in Son and<br />
eggs were<br />
the DGRC and the emerged<br />
(lable 2).<br />
State.<br />
col-Iected from<br />
It js proposed<br />
To prolecC Ehe remainjng population of ghariaL, the Soo chariat<br />
Sanctuary was declared over the Son river by the Madhya pradesh<br />
Government. The Sanctuary head-quarters is at. Si.dhi. The Sanctuary<br />
includes a stretch from the Ban Sagar Dam, which G under ccnstrucliod,<br />
to Uttar Pradesh border at the South of the Mirzapur DisEict. The<br />
length of the Sanctuary over the Son river is around f6O km and small<br />
stretches of t.wo tributories - Banas rivet \22.5 km) aod Gopadh ri.ver<br />
(25.7 km) are also included in the Sanctuary r thus totalung around<br />
2O9 kn of the area that is under the management of the Son Gharial.<br />
Sanctr.rary. The 'ridth of the river thaC is inc.Iuded inside the Sanctuary<br />
is 2O0m from both sides of the river badk- ceographicaLly, the Sancfitary<br />
Lies beLween the Lat.24'15tN and 24"40'N and Long.81"20'E and 82"50,E.<br />
Sbatus of Gharial i.n SGS<br />
in the Son river wa3 eslimated<br />
Afler decLaring the Sanctuary,
el.eases of gharial have been taken . place in Ehe Son river. So far,<br />
r t-rrl af 7. ^r^-ivF rarrod ,1:r'rl h^'6 \a6. --.,.cd in che son<br />
rrver rncluding 20 tharEL released during February 1988, \thich \tere<br />
caFtive reared aE the Deori Gharial Rearing Cmtre/ l'lorena ' Madhya<br />
Pradesh (Rao, 1988). AII the gharia-ls were ori.ginated from the eggs<br />
collected 1n the Nationa-l chanibal- Sanctuary. The Son river is a good<br />
habitat for gharia.l. No adult/breeding ma]e gharial was reported in<br />
the son river. Natural. breeding of gharial in son river j.,3 nct occ[rj.ng,<br />
ho\rever, !:he gharial refeased under rehabilitaLion paogran lne !ril-1<br />
start breedi.ng after sone nore years. Under the rehabiLieaLion Programme<br />
more captive reared ghari.a.L !ti-11 be released in the Son Ghari.al Sanctuary<br />
during coning years.<br />
Status of Mugger in SGS<br />
one pair of mugger nas released in the son river durirg<br />
1983. The muggers \rere captive reared a! the Kukrail <strong>Crocodile</strong> Rehabi-lita-<br />
Lion certre/ Lucknow, Uttar Pradesh. According to the estimate of<br />
the fieLd staff at the son Gharia.l sanctuary, a totaL of 4 nugger was<br />
present in the Sanctuary r including the 2 released nuggers (Rao, 1988).<br />
there are nany areas j.n the Son river/ q/hich are suitable for muggers.<br />
Ken Gharial SancbEy<br />
The Ken Gharia.I Santuary was declared over the Ken river,<br />
a tributory of River Yanuna, where gharial rehabilitation programme is in<br />
operaLion. The Sanctuary head quarLers is at Kajhuraho in Di6t. Chatarpur.<br />
The Length of the Sanctuary over the Ken river i-s around 45 km.<br />
39
40<br />
Statls of Crocodi-les ir KGS<br />
No systenattc crocodile status surveys have been under:laken<br />
in the Ken Ghariaf Sanctuary. Durirq f9B5 and f9B?, a total of 20<br />
captive reared gharial fron Deori chalial Rearing Centre, NcS, have<br />
been aeleased in KGS. Infornation o.l mugger populalion in KGS is not<br />
avaiLable. Ken river inside the Sanctuary is comparaliveLy more suitable<br />
for mugger than ghariaL. The area is havj.ng more rocky stretches<br />
and ninimaL water f[ow due to construction of dans i.n the upper reaches.<br />
St*lg d <strong>Crocodile</strong>s in Ot}l€r p;rtected Areas in it.p-<br />
Crocodjle population in Madhya pradesh, other lhan the<br />
populaLion in <strong>Crocodile</strong> Santuaries, are very less in number. A totaL<br />
of 25 nugger were released j.n Che Chandpata Lake inside the lladhav<br />
NationaL Park (De vos, 1986). During 1986, a tora.I of fO capeive reared<br />
gharial flom the Deori. Gharia-l Rearing Centre have been released<br />
in the van Vihar Naeional park at Bhopa-l (Rao, 1986). one pair of<br />
mugger from captive collectj.ons at Jaj"pur Zoo, Rajasthan has been<br />
re]eased in the Van Vihar, M.P., during October 1988. Muggers are<br />
also maintained in captivity in dj.fferent. zoos in M.p. A tctaL of 4<br />
mugger are under caplivity at Munj.cipaL Zoo, Gwalior. There are reports<br />
of presence of mugger in difEerent reservoirs, Iakes and rivers in<br />
the State, however, no data is available ol! thej.r status.<br />
Research<br />
Prior to 1983, scj.entiiic studies on crocodiles m madhya<br />
Pradesh have not been taken up. From June 1983, extensive studies
on ecology of gharial and flugqer ccoLl]at-Lons in lhe NaLiona-I Chanb3l"<br />
:.a nFin. .arrrc.l oui ..v _i6 _a:o:-.^ r-ra .. ,;,tdlije insLicule<br />
Jt lnd!d, Dehrad ja rn coLldoora:lon wiL.] )4adhya Pradesh Eoresr DepaflTenL.<br />
This incl'lded the use of Radio-tracking nethod and population nonitoring<br />
(Singh, 1985 and Rao, .1983). From cctcber 1.933, lhe auihor rem a-ined<br />
involved in monitoring of the ghariaL populaLicn includmg scudy on<br />
ghariaf neslinq actjvlties in Natiooaf Chanbal Sanctuary (Rao, 1988).<br />
The resu-Ils of the studies are usefuf for taking suilable neasures<br />
for the conservation management of the gharia-l and mugger in the Chanbal<br />
river and in other crocod ian habitats. The research 'nork in Chamba-I<br />
river highlighted for the first time Lhe mulLipfe role of crocodile<br />
Project because of the sinu-ltaneous conservalion of aIL aquaLic flora<br />
and fauna in a crocodile sancttlary. Here the stress was giveo to gangetic<br />
dolphin ( Plantj.nista gangelica)r otLers (Lutra 9P.), freshwaler turtles, etc.<br />
cdrdrlsion<br />
The best remaining popufation of ghariaL in the country is in<br />
M.P.7 where three santuaries are specially creaEed for the conservatioo<br />
of gharla.l. The onfy breeding tharial popu-Latlon in M.P- exists in<br />
the Chambal river, which borders M-P. with Rajasthan and ljttar Pradeqh.<br />
Hopefu.lLy<br />
/ after some more years breeding of gharia-l ltilL commense<br />
in olher rivers, parLicJ-Ially in Son river. lluggers are present in<br />
ditferedt \,ret-lands throughout lhe State. More sYstematic statlls surveys<br />
should be carried out, especial-Iy at reservoirs forned by the constructrcn<br />
of Dans and barrages. This ttil.L give a chance !o identify places<br />
for future rehabilitalicn of mugger. Surveys jn Bet\ta river, a tributory<br />
4l
42<br />
of rrver Jamuna shouLd be cond'lc.-eC t: lccate any remarning popufation<br />
or gcaridl and also Eo roelErry lne s{iEao.L-L.rE! o[ E'.]e ri.,'er ior gharia_L<br />
reha bi-iitatron. )loniErrrnl oi re.Leased crocodi-les has t. be ccntinued<br />
by the field sEaff of the Sanctuary/Protected areas where crocodi.Les<br />
are released. This has to be given high priority to eval"uate the success<br />
of the rehabi-litatjon progranmes in 14adhya Pradesh. Research sLudies<br />
on crocodile conservation are encoutaged for the betEer management<br />
of crocodjl.es in the Madhya Pradesh.<br />
R€fiererEeg<br />
Choudhury/ B.C. and Cho\rdhury/ S. 1986. Lessons from crocodrle<br />
reintroducLion projects in India. The Indian Forester, Vol.Il2,<br />
No.Io : 8a1-890.<br />
De Vos, A 1982. An evalualion of the UNDP,/FAO croccdile breeding<br />
and management project in lndia. FAO, Rome. Fie1d Document<br />
No.8FO:IND/74l046.<br />
FAO/ 1974. A preliminary survey of the prospects for crocodile farming.<br />
(Based on Ehe work of Dr.H.R.BusErd) FO:IND/7]/03:.<br />
FAO, 1975. India. Gharial. and crocodile conservatj.on management in<br />
Orissa (Based on the \rork of Dr.H.R.Bustard) - E'O:IND,/71l033<br />
pp. 1-15.<br />
Hussain, S.A., 1991. Ecology of gharia-I (cavialis gangeLicus<br />
) in the<br />
Nationa-l Chambal Sanctuary. M.Phil thesis, A.Ligharh Muslin<br />
Universlty, A-Iigarh.<br />
IUCN, 1972. Red Data Bcok - Repti-Ie6, Morges, Switzerfand.<br />
Rao, R.J. 1986. Management of crocodi-les and lurtfes in wet-Iand sanctL.raries<br />
of India- Tiger pa9er, 12(4):I-5.<br />
Rao, R.J. 1986. Captive rearing of gharial and turtles j.n National<br />
chambal Sanctuary. Zoo's orinc, I(Io): L7-18.<br />
Rao, R.J. 1988. Gharia.l rehabi-liEalion in the Son Gharial Sanctuary.<br />
Mi,neo, pp-12.<br />
Rao, R.J. 194d. N esLing ecology of gharia-I in NaLiona-L Chamoal SancEuary.<br />
Study report, I'limeo, pp.L05.
Rao, R-J- and Sharna, 1.K- 1985. :harisl rena.illcalicn in Madhya<br />
r.i.lo.-dDer/ IJ .)|2--..<br />
iirgh/ L.A.K. .1i35. inarFl ?opu.Lali.on :rend in Na::onal lhamba-I Santuar-1<br />
with ncEes on radio leleiTretry. itudY aeport/ l4imeo.<br />
Si.ngi!/ L.A.K.; Kar/ S.K. and Choudhurv / B.C. 1984. Indian Crocodi-Iians:<br />
A 1.0 year review of nanagement. Paper presented at the<br />
\rorking meeLing of te IUCN /SSC crocodj.le soecia-IisL group.<br />
Caracass. venezuefa. Oct. 1984.<br />
Table I : ResuLts oi captive rearrng programme of tharial at Deori<br />
Gharial Rearinq ceotre durinq 1981-1991<br />
Year<br />
198I<br />
r9a2<br />
L983<br />
1984<br />
1985<br />
1936<br />
I987<br />
t_988<br />
r989<br />
I990<br />
I']9I<br />
No. of<br />
coLlectec<br />
35<br />
35<br />
40<br />
4{)<br />
63<br />
L8<br />
a2<br />
61<br />
40<br />
No. of<br />
eggs<br />
hatched<br />
26<br />
35<br />
3'7<br />
63<br />
T\2<br />
BO<br />
29<br />
39<br />
No. of<br />
animals<br />
dead<br />
10<br />
L2<br />
16<br />
38<br />
48<br />
No. of gharia-l released Present<br />
Stock<br />
Year Area No.<br />
1985<br />
r986<br />
.I986<br />
r9B?<br />
1988<br />
I98B<br />
19d9<br />
1989<br />
1988<br />
KGS<br />
V anvihar<br />
Vanvihar<br />
KGS<br />
SGS<br />
SGS<br />
NCS<br />
NCS<br />
NCS<br />
524 46.r 10 2t9<br />
t0<br />
6<br />
l0<br />
4<br />
l6<br />
I<br />
15<br />
4<br />
25<br />
49<br />
80<br />
.Lt<br />
39
Table 2 : Res"rILE of captive rearing programme of :^n uqge. DGRC<br />
1987<br />
1990<br />
col-IecEed hatched<br />
27<br />
20<br />
22<br />
It<br />
),io. of animals<br />
dead<br />
l<br />
Present<br />
stcck<br />
rI
o.-il9-. r-<br />
l- tlaLiaEl Charbal S dErt|<br />
2. Xst CharLl SdEtsry<br />
3. Sa! chirll Srd|Dry<br />
45
4('<br />
ALLIGATOR NEST DETECTION PROBAAIIIIIES<br />
DI'RIIIC AIRIAL SURVEI IN ALORIDAI<br />
Kenneth c. Rice'. H. Frankl.in Percival', and Allan R. Woodrald"<br />
'<br />
u.s. aish a!|d wildlife service, Florlda coopelatlve Pteh and wtldltfe<br />
Research unlt, Dept. of wildlife and Range Sciencea, Unlver6lty of<br />
Flortda, cainesville, alorj.da.<br />
"rtoriaa oame and Fresh Wate! Flsh ConmtBsion, caineEvitle. Florida.<br />
Detectlon probabtl.tties of aLllgalor nesta or other obJects of<br />
lntereEt nay differ due to variatlong tn vegetatlon, topogrephy, obaelver<br />
€xpelience, a.al other €nwlromsntal factorE (Nofton-crifflths 19?5).<br />
Thelefore, the probabtl,tty of detectlng aII neatg tn any sanpltng unlt<br />
nill uEualLy not equal. I (caughl.ey and crlce 1942). Adjustment of counts<br />
by some faclor is essential to elirninate btas assocfated with unknoitn o!<br />
varlable detectlon probabillti€s. ln Florlda, femaLe alligatolE nea! in<br />
very dl-verse habitat6. Most notabLy. r!€Ets aPPear rnore difftcult to<br />
detect fron the atr tn areaE with heavy tree canopy.<br />
D€tecll.on probabtlittes may elEo b. aff€ct€d by dtff€rences 1n<br />
ob.elver experience (Norton-srif f iths 1975). The develognent of e<br />
spectflc search lnage and the ablllty to dlscern t€rr€Bttlal obJect. fron<br />
the ei! are garneled through experience. rn additlon, some indivlduals<br />
rnay develop these skills at differing rateE and attatn differing levela of<br />
competence due to viEual aculty o! other tnher€nt factors (Ueace 1969).<br />
Expertence may be eapecLaLly irnportant uhen searchLng fo! partLelly hldden<br />
or canouflaged alligato! neEtE. AddltlonalLy, ptlot expeliBnce tnay affect<br />
these probablllties. 8xp€rienced pilots may provLde for a more efficient<br />
surv€y by fLying only lrithin neststng habitat wtthout repeated lngtructlon<br />
fron the observer (Norton-cllffithE 1975). rhis allows the obEelve! to<br />
rPresenteal at the<br />
the IUCN, at Vl.ctorLa<br />
llth vrorking Meeting of the crocodll€ sp€cialiEt croup of<br />
lalla. zlnibab$e, Augnrst
4',7<br />
concentrate sol€ly ott n€st search.lng and not on navlgatlon, 6Paed, end<br />
.ltituale. ifhile these differences naY not lncrea6e EallPling €rtor, th€v<br />
l|ay biaE the €atimato!.<br />
once al€tectlon Probabillttes have been calculated, they l|ay be uaed<br />
to consuuct nest productfon 3.tl-nat€s via an adjustnent to . dlroct count<br />
o! l.n conJunction with othel nethods such aE tran6ect cou!!t€. An tnltial<br />
aleciElon was nade to concentrat€ sanPllng effortE along several line6 of<br />
htrpothests t€Btlng. the p!i-na!y line of gu€stioning lnvolved dev€Lopltrg<br />
d€tectlon probabl-Iiti€s for all'igatot n€st surways and estlmatlon of neit<br />
populatlon€. s€condalily, ne tested the nulL hyPotheEts of no dtffe!6nce'<br />
1n the6e plobabilitles acrios. yelrg lrd priinary habitat ty!,es. und€r thla<br />
te6t, ne assuned that all obBerv€Es $ere erPelienceal r,lth alllgato!<br />
n€sting surv€y3. goweve!, with Eev€!.l new btologi.t. €nt€ling an<br />
s.pandtnq rlll.gator tnanag€rEnt proglam tn Florlds, lJe .a!, ttrs raed to t6at<br />
th€ h)rpothesis of no diff€lences ln detection Probabilltlas trnong<br />
experience lev€ls. The avaflabtllty of observers dictated the amount of<br />
€ffort applied to €ach questlon. Einally, w€ tested th€ null h!Poth€61's<br />
of no differenc€ in det€ction ProbabtlltieE betl'€en two lev€la of Puot<br />
exPellence.<br />
AddltiodaLly, xre nere LnteleEteal in the f€aslbilltY of the uae of<br />
aerl-al, Iin€ tran€ect m€thodologY tn nest e.ti-natlon. Ih€refore, we t€st€d<br />
the null htrPothesls of no dlffsrence bet*€sn e€tl$.tes obtalned tlttoqgh<br />
cooPlete and tlangect countE.<br />
ltethodoloov<br />
Studw areaB. arro types of nalsh sy6temg anal lhree tl.Pe6 of nerah<br />
cov€r u€re d€ftned to rePlesel|t maJor afligato! nestlng eleat ln llotlda.<br />
An €.:t6rd.d '.ar'h sysxen itas defined !s an area t'l.th extanslv6,<br />
homogeneou. vegetatlon as alll-gator nestlng habltat. A a€cond systa&.<br />
crlled a Dourded staip ateat conEisted of a relatlvely natloit 6trlp of
n€sting habitat betwe€n open wat€! and upland veg€tatlon or other.brupt<br />
cbangea tn habltat. ltarsh cove lthln bounded 6trlp ar€aa \ras diwtded<br />
lnto op€a, patXieT.Ty pooded, anal rood€d ayatens. Open Bysten€ nere<br />
mar6heE with sot canopy. Study areai w€re choEen<br />
that haal a hl-Etory of relrttvely dense nestlng !o provlde adequate sa$pLe<br />
Elz€ udder 5 Limited budgets.<br />
Lake Okeechobee, a shallow, 191,223 ha lake ir south-central Florida<br />
(Okeechobee, clade6. sondry, Palm Beach, and Uartln countteg) repregeDted<br />
an extended marah siBtem {rtgure 1.). An extenEive mar€h along th€<br />
w€atern ahor€ of the Iahe contained the najolity of alllgator nestlng<br />
(pelaonal obaelvation). l.{arahes assocLated h'tth leveeE on tbe nolthern,<br />
eaatetn, .nd southeln peltmeteis of the Lake w€re limited anal contain€d<br />
f€i, neats. Co1l€ctlvely, inarghes constltuted an area of 3a,OOO ba.<br />
Vegetatlon conglsted chlefly of Typha alodengeasia, Eleochatia celTufo'a,<br />
Rhynchogpora Xracyi, Sa]it carolinianat Scirpug calito'.aictce, CLaaliu'a<br />
Jaaaic.aab I and rntxed gra.sos (Milla€on 1987).<br />
Llke J€ssup, ln €as!-centrll alortdr (sentnote coqnty), waa<br />
categorlzed aE a boulded Etlip alea and an open Bysten { Ftgnrre 1). Lake<br />
JeaEup rraa a 4,805 ha, euttophlc, al.kaline, natural lake ln the St. Johns<br />
Riv€r akainage ba.in (Canfi€l.d 19Al). the pridary ne€tirg erea was a 996<br />
ha narBh o|! the northeaEtern portion of the lak€. Sand cordgrass<br />
(spattira lakei.i ) anal giant leed lPhragnites aust1alis) were the<br />
predoninant v€getation types (Jennings et al. 19841.<br />
qrange l-ake, locateal in nolthc€ntral Floaida (Alachua Countsy),<br />
r€ptaE€nt€d r bound€d strrP ar€a and a paEtielly wooded syatem (Flgule 1).<br />
ThiE ay8ten, 5254 ha, incLuded 1188 ha of potentl.at alllgator negtlng<br />
habitat. Characteristic of the narsh area was an accunulation of peat,<br />
resultLng in extenstve fl.oattng islandB of vegetatlon. Vegetation<br />
con€isted prfuilnallly of Sagittatia Lahcifol.ia, C]a,tiun j a,aic6'rsig,
Ilyclrocoxyla wnbeTlaxa, tyrica cerifera, cephaLatthue occident.Ii.s, and<br />
Decoaloa verticiuatu.E (Deltz and aine6 1980).<br />
Lake crtffin, a 5575 ha, eutrophic' hardwater natural Lake l-n central<br />
llolida (!ake County), lepleBented both a bounded Etrlp area and e r^tood€al<br />
system (canfield 1981) (Figure 1). A s25 ha woodad swanp occurr€d in a<br />
narrow band proxinal to open vrateli ma!3h (1231 ha) occurred beyond th€<br />
eooded marsh (Jennings et al. 1988). vegetation consisted Pritnarll'y of<br />
SaJ.ix Bpp., yrica cerifera, sagixxaria Laneitolia, and C.ladiut<br />
laynes Prairie state Pleserv€, a 73oo ha wetland ln north-centr.l<br />
Alorida (Alachua county), waE utilized for the transect aanpling portlon<br />
of the study (Figule 1). Nestlng areas t,e!e catagorlzed as mixed<br />
persistent and noope!8iEtent, emergent, paluEtrine w€tlandB l-ntellaced<br />
with Ecrub-shrub. Plimary vegetation in thts region consl6ted ot Paai-cun<br />
henixonont PoAteileria coralata, PoTygonun spp.,, sa.li:. .tPp., cephtTaathuB<br />
occidenxafist and sal1'bucus canadensis (Nesbitt and wLl}Larns 1990).<br />
Alliaator nest survevs. Aerial survey6 were conduct€d ftom 2-.eat,<br />
piEton-engLned helicopterg during June and July of 1949-1991 to cenaus<br />
alligator nests on the 4 baaic habitat tl.Pes identified above. Portlona<br />
of each survey were dupllcated by 2 or more observelB to conatruct end<br />
conpare nes! sfghting probabil.lties. ahe numbelB and ttp€s of observelg<br />
plesen! on any s\rrvey rere controlled by avallabtltty of obdervers of<br />
lequired experience levels.<br />
The inltial observ€r conducted a 6ulwey along the lakeEhore or ltalsh<br />
ln suitabl€ nesting habitat. The survey continu€d until th€ obsslv€t had<br />
counted approxlmately 30 nests.<br />
Flighte lasted 1to 1.5 hours to insure adequate Eearch ttme while<br />
remal.nirq withid budgetary constraints. surveyB wele conducted at 40-50<br />
metels altituda and 25 to 30 knots airspeed. lhe Pilot wa€ directed to<br />
fo!.Low the lnBtructiong of each observe! except to lrsure tba! all<br />
EubEequent obeervers lemained withir the area deflned by tbe initiat<br />
49
50<br />
observer. aherefore, surweys could hawe dlff€l.ed ln such factord .s<br />
diEtance flon oPen rratet, ti.ne €pent searchlng ln e giwen vegetetlon type,<br />
etc. the pilot could adjust any factol fo! gafety concerns.<br />
At €ach neBt location, tha plLot vtould hover ovar th€ sl-t€ to allot<br />
ths obgerver to obtaln a loran locat.lon and to record the locatlon on<br />
1";eOO' aettaL photograPhs {Flortda Department of TransPortatlon,<br />
laLlahasBee, rrortda). On rake Okeechobee' Ioran locationa were uEed<br />
Durlng the Period of these surweys (June-July) ' sub€tanttal nest<br />
constructlon occurred ovelnight. Therefole, all obsetverB on a given<br />
survey conducted flights on the 6alne dav to alleviate estimation problem6<br />
aBgociated wtth open Pop\rlationg. ao insure Etnlllat viEibtl'ltv conditlons<br />
Ln r€Iation to fog' shaalows, and thunderEtorns, alM.lghtB we'e flo6<br />
lrithin a 3 to s hour period beginning mld-morntng (usuallv o9OO).<br />
calcutation of €iqhtind probabllltLes. llests nele marked<br />
individuatLy by naPping and by loran, !€sultLng in knoltn Palallel3 ln<br />
stghting by observers. For those sulweyE conducted by onLY 2 obEerve!9,<br />
u€lng notation floill I,lagnuBson et al. (1978), we [oted tho.e nett6 se€n<br />
onty by observe! 1 (5r), tbose seen otrly by obaerve! 2 (5r), and those ae€n<br />
by bolh observers (a). sighting probabillties<br />
(p) of each observer wele egtimated by:<br />
and<br />
Because ti was a etandard binorolal eetimator, alandard etlola were<br />
estsimated by:<br />
A=<br />
B<br />
(B+s")
and<br />
sE (p2'J =<br />
,9E', (F1) =<br />
UultLple-surveys by 2 obeelvers allowed for the use of a nodlfied Peterson<br />
esti.rnator (chaplaD 19s1), lthich ie degtgned to reduce bias a€6oclated with<br />
6nall sarnple Eizes. lhe e6tltnator nay be wrltten as :<br />
(s1+B+1) ( s2 +E+1)<br />
(B+1)<br />
.5'.9, (s1+B+1) (S2 +E+1)<br />
var tnt = _-__iB_a\_@;l<br />
trhere t iE an estimate of PoPulation size.<br />
Vrhen 3 or 4 independent obgerwers w€re avallable for counta' an<br />
estirnate of populatLon size !ta6 obtalned with Progran CaPture (Otl-a et aL,<br />
19?8). Estimates of proportiong of nests Eighted by anY observer (ii) were<br />
obtained by rr,ri where ,i was the count made bv obEerwer -r and tr 'as the<br />
DoDulatlon esthate. lhe Etandard elror o! fr was calculated by:<br />
gE (brl<br />
ffi<br />
These proportlons (detectton ProbabilitteB) ltere used to nak€ conparasona<br />
of sighttng frequencles amonq indi.vtduals, €xPerlence 1evel6, years, and<br />
habi.tat6. The calculated poPulation eEtinates obtained qtere conpared<br />
to total counlE of nesls ltith gimPle linea! leqressfor techniques. total<br />
countg nele established after repeated surveyg durlng e99 coLlectlon.<br />
51
obeelver experience. obselwers were divtded into groups dellneated<br />
by experience level. ExpetienceCl observerg lrere tltoge wlth extenEive<br />
survey tjjn6 on a qiwen Etudy area. uediun-ezperiehced ob8€lverg l'ele<br />
experienced with alligator nest Burweys but unfanlliar with the Patticura!<br />
stualy area. Inexpetieaceal obselvers nere qualified btoloqistB that were<br />
unacqualnteil uith al.Ii.gator nest Eurveys and had only mlnlmal exPerlence<br />
wlth alligato! neEting. The effect of PLLot<br />
experlenc€ on the sigtlting<br />
probablllties of both exPelienced and inexperlenced obBerwers 'as aIEo<br />
teet€d. Pllots were categorlzed aa experience)l (havlng f1oll,r many nest<br />
Eurveys) or jnexParieaced (having newer florrn a ne6t sulvev) '<br />
I,ine transect. The section of Pavnes Plairie State Preserve bounded<br />
by I-75 on the west and us44l on the eaBt was divid€d I'nto 20 €qual<br />
transects of 150 m wialth. Two observets conducted nest counts on aLl 20<br />
tranBect6. Tlansects rere later randomly chosen to construct egtinates of<br />
the n€st populatLon at levele colresPondisg to 25 and 5Ot of the total<br />
Eurvey area. A eeParate populatlon estinate lras obtained vla the chapman<br />
esti.nator from the 2 individual surveys. The 2 transect-based estioates<br />
were conpared sepalately and by observar to the Cbagnan estimate uitb ttre<br />
standard z-Etatistic for cornParison of two neans (ott 1988).<br />
Analveis. An analysls of warlancs Procedure nas ueed to test the<br />
aliffelence in aletectLon Probablli'ties between the 3 obselver exPelience<br />
lewel6 (SAS Instltute Cary, NC). A contlaEt proceduro was used to compare<br />
the linear and quadrattc proPErties of the relationshiP b€tween det€ction<br />
probabiLitieg among the exPerience levefg. Notably, we €mPloved 'os aE<br />
the crltlcal value for rejectlng the null hYpothesia of no difference<br />
ainong expeli€nce levelg. soweve!, for multiple comParisons, thi6 walue<br />
$as adjusted by the nunber of compalisons to .016? (Bonfeftori<br />
adjustment).<br />
Theoretical quantile-quantlle plots wele empLoyed to conpare ttre<br />
alepartureE fron nornality of 3 methodE of data transfolnatlon' Ihese<br />
plots conEigted of Plottlng the quantiles or ranks of the resldualg of tbe
tlaosformed data against the coriegponding quantilea of a theoretical<br />
distrrbutton, which in this instance, was tbe normal dlstltbutlon<br />
(chanbers dt aI. 1943). Ahe plot, if the data ls normally dlstrlbuted,<br />
should follow the line y=x througb the oliqin. Vfe l,ere concerned L'tth<br />
serioug departureg floh th€ normal distlibution and cho6e a tranaformation<br />
whlcb best fulfflled the assumptton of normality. The Etandald<br />
transformation for proportionaf data ia the alcsine (ott 19e8). re chose<br />
to conpare thig againEt a weighted transformation. The ploporttons lrere<br />
calculated as blnonial functionE allowing fo! the calculation of a<br />
standard error. A weighting function waa then caLculated by the tnvelse<br />
of the vafiance. The thild rnethod of tranafornation evaluated wa6 a<br />
conbi"nation of both the arcstne and i'eighted trang forrnatlonB.<br />
Untran6f ormed proportioDa u6!e algo evaluated.<br />
We utffized an analysls of varlance procedure to detect habltat,<br />
yearty' and individual effects. slmple effects (pairwige comparlsonE)<br />
were te6ted witb both the Duncantg nultiple-range teet anal l€a6t squares<br />
means procedures (sAs Instltute cary, Nc).<br />
A chi-Equare teEt of independence waB enployed to test the nuLl<br />
hypotheBia of no differen:e in detection plobabilitles between expertenced<br />
and inexperienced observers and experienced (5 yeals) and lnexperienced<br />
p!1otE.<br />
Resutts<br />
Obselvations. Thirty-two observations were lecorded durtng thig<br />
Etudy. Each obgerwation coDgiEted of an estinate of the detsection<br />
plobabll1ty for a partlcular obserwer on a given aulvey. Theae<br />
obserwationg were paltitioned anong 9 individuaL observers, 3 experience<br />
lev€Is, 4 habitat types, and acrosg 3 neBting €eaaong (Table 1). lvelv€<br />
separate tlenE€cts w€re surveyed and evaluat€d. obEerwations by<br />
expertenced ob6ervers nu$elous due to preEence of suitalrl€<br />
obBerYera at a given aite.<br />
53
54<br />
Detection plabebiMleg= ltean detection probabilMes, Etandard<br />
errors, anal 95$ confidence intervals were i = 0.7567. SE = 0.0931, and CI<br />
= 0.?315 to O.aola for exPertenced ob€ervers, i = 0.5759, sE = 0.1188, and<br />
Cl = O.4362 to 0.7156 for nedium-expelienced obselvers, and * = 0.4488. sE<br />
= O.1409. and CI = 0.3453 to 0'5523 for inexperlenced obBelverE.<br />
Population estimateE w€re calculat€d for each transect wia the Cbalnan<br />
estlmator (2 obEervers) or Prograo capture (3 or more obaerwers) ' lhe6e<br />
eEtimateg were si,nira! to totat nest countg after repeated sulvevE durlng<br />
egg col!.ectlon (/ = 0.933) (Ftgure 2).<br />
Transfolmalion. After comParing quantile plots, t 6 uEed ! lteighting<br />
function (inverse of the variance) to tlanEfortn ploPortion data (Flgure<br />
3). The othe! transfonnalions (arcslne and a coribination of arcsine and<br />
wetghted) antt the untransforned data aPPeared to slightly skew the data<br />
anay from th€ line y=x. In addltion, these nethodE seemed to suggest the<br />
plegence of outllerB. we further plotled the resldual wE. exPected walu€s<br />
from the chosen transfornation (ANOVA model of proportlon stghted -<br />
obEerver experience lewel) and f,ound no violation of the assufiption of<br />
equallty of varianc€s (Figure 4)-<br />
obEerwer experience. Proportslon of nests observed differed anlong<br />
experiedce levelg (P
!-!!e-l!e!!9g!: No dlfferences were lound belween estlmate. ot'tain€'l<br />
wlth Li.ne transects at elther the 25 or 5Ot LeYel and tbe chapnan<br />
esti.rnato! (z=O.036 and 0.049, reapectiwely; P>0.05).<br />
DlEcusslon and concluslona<br />
Nest detection plobabtllties. For any managernent legime based uPon<br />
counting an unknown proportion of a resource, tbe probability of detectlng<br />
an inallvldual nust be ewaluated and quantified. lb€ wartatlon asEoclatsd<br />
r.rtth this probability due to diffellng observ€rE, habltatB, and seaEona<br />
nust al€,o be addlessed. Alligator nesting in Florida wetlands occulE over<br />
vory div€'se vegetation types, cov€r, and tretland!. During a n€stins<br />
6urvey, the actual count Ehould be adjusted bv an approPriate detection<br />
plobability to account !o! these factora.<br />
A nean of the delection probabitittes fron this study can be used !o<br />
construct a coriection factor for fital Population €Btl'mate3 involving<br />
alllgator ne6t Eurveys in Florida. This corlection may be written aa:<br />
tr=<br />
where c iE the initial count flon the nest survev, i is the estlnate of<br />
detection plobability (o.7567 wlth sE=o.0931), and f tE th€ flnaL<br />
Populatton<br />
estimate.<br />
obE€rver experience. we found expelieDced obEelvers to exhibit a<br />
bigher det€ction probability. conc€iwably' develoFtr€nt of, . 8€arch 1$ag€<br />
fo! a partlcular Ette-specLflc nest tyPe was the dstellnlnlng fector_ i{e<br />
have not€d both er.pelience and indiwidual baEed laarnlng aliffelenttalE'<br />
Although we found no difference in neEt detection probabilitieg rretreen<br />
medLun and inexperieDc€d observerE, the contrast was almogt algnificant<br />
{P=0.o349). Thi6 could indicate that the folmer grouP of obsetvers.<br />
through conlinueal surveys on a glven area, uould deveLop the aPploprlate<br />
search iinaqe and survey reglne at a hlgher rate than the inexPellenced<br />
observer gloup, rhe tneditrm-experienced observer gloup was perhapg<br />
;<br />
55
56<br />
undeftepresented in thiE experinent due to lirnited awailability for a<br />
Indlwidual learning valiations were also evident. The confidence<br />
lntervalB of tbe 3 experience levelg were empirically dlfferent. A<br />
comparlEon of the confldence interwal limlts indicated I€ss valiability in<br />
the exper!€nced category. thls could be attribulable to .anPllng effort<br />
o!, more likely, individual learning rates. ExPeri.enced obEerver6 may<br />
have developed site-apecj.fic Eearch images through Eeveral surveys on a<br />
giv€n area. ahis longterm develognent may haw€ reduced individual<br />
variation by allowlng all obserwers to lealn at differing rates.<br />
EventuaLly, the individual. acquired an effectlve search Pattern that<br />
approxiinated others in the group. The other obeerwer groups are placed ilr<br />
r€latiwely new situationg. Inherent indj.vidual learning rates ale<br />
displayed thlough larser confidence intervalB (or variances). rhrB 16<br />
lmportant to management p€rsonnel, as this intervat would be used to s€t<br />
halv€st quotas. Whil"e we can predict the detectlon probability for all<br />
obEervar groups, the wariances exp.essed aa confidence lntelvaLs fot<br />
medium and inexperienc6d ob6erverg nay be too graat for management needB.<br />
Pllot experience. Pllot experience alial not affect detection<br />
probability in our llnited experiment. Presumably, this iE attributable<br />
to our 6tudy design .i.n which the pilote foltowed direction given by the<br />
ob6erve! rather than declding on fligbt patterns th€mselves. ThiE furtber<br />
gupported our conclugion that any diffelences in detectlon plobab!:-ities<br />
between obgerver6 were directly attrlbutable to varying experlence level.<br />
Although experience of the pilot did not affect the ProporlLon of nestE<br />
stghted, experience certaLnly affected safety and confort.<br />
labltat variation. OnIy exPerienced obaervers were used to conpare<br />
habitats and yearly varlation due to ganpllng effort. we did not final a<br />
dtfference in neEt detectlon probability for the 4 habitat types. Ihtg<br />
probablllty, or correctlon factor, aPPIies only to thoae neEtE observable<br />
from the air. lt does not apPly to those nsBta that are completely
obatruct€d by vagetatlon or oth.!nL6€ und.tect!b1.. Th. p.oportlon of<br />
n.tta th.t ere unobsstvrble f.d th. al.r n y dlff€r b€t$s€n h!bl-trt..<br />
Y€arlw v.rlatlon. lfe iurpect.al th.t vegetrtlon dlrtrlbutlon rnd<br />
d€nstty change du. to wrt.r Iev6I v..lrtlon rnd other €nwlronaent.l.<br />
frcto!. dlght Lnfluenco d€tectlon plob.btlttt€r. Howew.!, r'r€ dld not ltnd<br />
.ny yeatly vatl.tlon Ln n6Et al.t.ctl.on paobablllty. Enh.nc.d<br />
observ..blLlty of ne.t. alu6 to riodlflcrtl-on of the L@€dl.te er€.<br />
surroundtng r na.tlng ait. by fsmrls aLLtgato$ nry haw. off.et .ny<br />
n.turrl varlatlon ln habi.t.t qomposltlon.<br />
Lln€ tranaect. On rr€ag wlth large, falrly hooogsn€oua n€atlng<br />
a!€as, line tleng€cts cad provLd. rn afftct;nt anal r€I1ebl6 estlfiet€ of<br />
!,ofnrL.tlon .!re. Wlth . c.rtel.n .nount of pr.-pllnntnq, r ne.t e.tlnat.<br />
could bo obt.h€d by actu.lly countlng 251 or 1,.r. of th€ .tca. lr. foudd<br />
no reagon to bell.ev€ theae eatltnet€! souLd b. rny las. r.li..bl. than totrl<br />
count€ of th€ area. We alo f€€I that th6 uss of thts tochntgu. .hould b€<br />
expanded to lnclude very l.rge rr.a. (.uch .. th. Evergl.de. .nd<br />
@ns€rvatlon A'raar) .<br />
Sggg!.g31ggCs Ah. pac.€nt huveat tur lLolld. of .!rly rg€-clr!!<br />
alllgetorr (eqg .nd h.tchllngr) I. b..cd upon r 50t r.oov.l of totrl<br />
9roductLon. rh. orlglnal ..tl-ortc. of proaluctlon alurLng . llorLal.<br />
CooPer.tlv6 !l3h .nd rLldlll. A€.earch UnIt r....rch proj.ct r.rc b..ed<br />
uPolr r€peatod nelt countl on a 9lv6n alea ov€r the coursc of the neltlng<br />
aeaaon (il€nnLng. 6t aI. lga8). Ih... €.tLm.t.. c@p.!. rreLl to . ringl.<br />
count whlch h.. b6en corr.ct.d by th. d.t.ction probrbiLlty gle.n .bov..<br />
Ho$cvar. prcaclt Drttrgsnt artl t€r ara bea€d upon r al,Dgla auravay that<br />
1. not cort.cted by thl. plob.bl,llty (D. D.vld tr.!.. co@un. ) r.d,<br />
th.!.forc, tr negrtlvcly bl..€d. otsh.r f.ctor. th.t .hould b. .aldr.....al<br />
.t .dc I,olnt lnd that lnflu.nc. tot.l prodsctlon rt|. .1.t.-rp.cr,llc<br />
alcpr.d.tion, floodtnq, rnd ai.porltloa !atc.. ah. ..tl!.tlon of a!.t.ctlo..<br />
probrbllltl.. lr onLy r f1!.t .tsp Ln forolng . coopr.henrle. aod.:, lor<br />
alllgrtor !..t ploaluct loa.<br />
51
58<br />
IITERATURA CITED<br />
canfieLd, D, E. itr. 1941. Chemlcal and trophlc state cbaracterlgtlcs of<br />
alorlda lakes 1n letation to regLoral geol-ogy. FIa. cooP. liah and<br />
tfll.dl. Bes. unlt alnal Rep., unlv. of Fl.a., Galnesvllle. 444PP.<br />
Caughley, c., and D. Grice. 1982. A correction factor for counting<br />
emus fliom the alr, and i.tss aPPlicatton to counta in We6tern<br />
Australl-a. Austr. Wtldl. Rea. 9: 253-259.<br />
Charnbels, J. l{.' w. s. clev€land, B. Klelner, and P. a. Tukey. 1983.<br />
crephical nethods for data analysls. Brooka/cole Publ. co. Pacific<br />
Grove, Callfolni.a. 395PP.<br />
Chagnan, D. G. 1951. Som€ propeltieE of the h)Perqeomettic<br />
dlgtflbuti.on with appltcatlons to zoologlcal cen€uses. uniw.<br />
calif. Pubric. stat. 1:131-150.<br />
Deitz, D. C., and l. c. gineE. 1980. Alligator nesttng in north-centlal<br />
Florlda. copeia ].9AO (2t 1249-254.<br />
JenningE, !t. L., H. r. Perclval, and A. R. woodward. 1984.<br />
Evaluatlon of alligator hatchling end egg removal frorn tb].ee<br />
alorlda lakeg. Proc. Ann. conf. s'8. Assoc. Fiah and wildl.<br />
Agencieg 42: 283-294.<br />
l.tagnuEson, w. 8., G. J. caughley, and G. c. crigg. 1978. A double-<br />
€urwey estlmate of popuLation slze from inconplete counts. J.<br />
rilldl. Manage. 42t 174-r'75.<br />
l{enee, A. J. 1959. Psychological. problema of conducting aetial<br />
cen6uEes from light aircraft. E. Afr. Agrid. For. J.<br />
34 ( Bpectal lssue):44-45.<br />
l.tllLeeon, at. P. 1987. vsgetative changes in the lake okeechobe€ littolal<br />
zone. south alorida water [anagement Dlstrlct aech. Pub. 87-3.<br />
IteEbitt, s. A., and K. s. wtlllans. 1990. Bone range and habita! uae ot<br />
alorida sandhill craneE. J. wlldl.. uanage. 54(1):92_95.<br />
lolton-erifflths, !{. 19?5. countlng aDlmaIE. Afrlcan wll.dllfe<br />
!€aderghip Foundatlon, Nalrobi, Kenya. 134 pp.<br />
otis, D. L., K. P. Bulnharn, G. c, tthite, and D. R. Anderaor!. 1978.<br />
statiBtlcal inferences fron capture data on closed Populatlon6.<br />
Wildl. I.lonogr. 52. 135pp.<br />
ott, r. 1948. An introduction to stati.tical methoda and d.ta<br />
analysig, Thtrd ed. Pws-Kent PubL. Co., BoEton. 835PP.
Tabl6 1. Proportton of alliqator nestg obEerved by study area, trenBect,<br />
€xpeltence lewel, and observer.<br />
STUDY ARTA<br />
€riffin<br />
6riffin<br />
YEIR<br />
1939<br />
1989<br />
1989<br />
1989<br />
t9a9<br />
lgSo<br />
t9a9<br />
l9a9<br />
1990<br />
1990<br />
1990<br />
1990<br />
1990<br />
l99o<br />
1990<br />
1990<br />
1990<br />
t990<br />
l9o0<br />
t99o<br />
1991<br />
1991<br />
1991<br />
l99l<br />
1991<br />
l99l<br />
1991<br />
t99l<br />
l99l<br />
t99l<br />
TMlistcrr<br />
__!q!E!<br />
Itrrn3.ct3<br />
i€.e nq6.r.d con3.c{tiv.ly tlruugho{t studyi<br />
tl-.rD.ri.m.d,<br />
r€.. nDb.md iidivid!.lly fo. lrtor .dly3is.<br />
t<br />
I<br />
I<br />
3<br />
3<br />
2<br />
a<br />
I<br />
1<br />
1<br />
5<br />
5<br />
5<br />
5<br />
8<br />
8<br />
l0<br />
l0<br />
to<br />
9<br />
t2<br />
t2<br />
t2<br />
It<br />
1l<br />
ETPER.'<br />
LEVTL<br />
!<br />
I<br />
I<br />
2<br />
3<br />
1<br />
2<br />
I<br />
I<br />
t<br />
3<br />
3<br />
I<br />
I<br />
3<br />
3<br />
I<br />
2<br />
3<br />
1<br />
2<br />
I<br />
I<br />
1<br />
1<br />
I<br />
I<br />
I<br />
1<br />
2<br />
I<br />
2<br />
!<br />
I<br />
I<br />
z<br />
3<br />
5<br />
6<br />
1<br />
2<br />
2<br />
I<br />
3<br />
5<br />
I<br />
2<br />
I<br />
I<br />
2<br />
2<br />
I<br />
I<br />
PROMRTIOII<br />
OBSERVTD<br />
.7360<br />
.7179<br />
.1426<br />
.ttla<br />
.5870<br />
.6071<br />
.50q,<br />
.8571<br />
,6923<br />
,8491<br />
.!204<br />
.3396<br />
.lr23l<br />
.a7u<br />
.4103<br />
.564!<br />
-62a5<br />
,6458<br />
.t583<br />
.29t7<br />
-aa31<br />
,7209<br />
.62t9<br />
.647t<br />
.6rtt1<br />
.804t<br />
.7405<br />
.w,<br />
7t57<br />
.tl,l3<br />
.8214<br />
2r.dtr, 3in.rpEi.nc.dr<br />
59<br />
STAIiD.<br />
_!@B<br />
.0711<br />
.0fzL<br />
.0638<br />
.0687<br />
.0921<br />
.@57<br />
.l'6a<br />
.0905<br />
.t,626<br />
,0656<br />
,0669<br />
.0453<br />
.0555<br />
.079t<br />
.oaoo<br />
.@15<br />
.081r<br />
.@75<br />
.@ll<br />
.0too<br />
.0491<br />
.t58a<br />
.0734<br />
.@1,<br />
.06t9<br />
.0626<br />
.0652<br />
.04t5<br />
.079,1<br />
.08@<br />
.0t16<br />
tob!.rv..3
Florida, U.S.A.<br />
Figure 1. Location of study areaE in Florida.
TOTAL COUNT<br />
55<br />
Figure 2. ConParison<br />
nultiple surveYs v9.<br />
s'rllveys.<br />
35 /tO<br />
ESTIMATED NESTS<br />
of estinated nuDberE<br />
total nests counted<br />
61<br />
of nestE froD<br />
after repeated
62<br />
a<br />
{3)<br />
(o.31 (0.2) (o.1) 0<br />
RESIDUALS<br />
Figure 3. Theoretical quantile<br />
observed lreighted by the inverse<br />
,{'<br />
o.1<br />
a<br />
plot of proportj.on<br />
of the variance.<br />
o.2<br />
of nests<br />
o.3
RESIDUAL<br />
o.3<br />
o,2<br />
o.1<br />
o<br />
(o.1) a I<br />
(0.21<br />
I<br />
(0.31<br />
o.4 o.5 0.6 0,7<br />
EXPECTED<br />
a<br />
ra<br />
a<br />
a<br />
t<br />
a<br />
I<br />
a<br />
I<br />
a<br />
I<br />
63<br />
o.8 o.9<br />
Figure 4. Residual vs. Expected values fron ANOVA nodel of<br />
proportion sighted = expelj-ence 1evel, with proportions of<br />
nests sighted veighted by the j.nver6e of the variance.
@<br />
crocod i les in Canbodi.a<br />
Parntep Ratanakorn<br />
wildlife Research Laboiatory, Departnent of<br />
Zoo|ogy, Fdculty of scletrce, Kasetsart University'<br />
Bangkhen, Ban€kok 1o9oo, ThaiIsnd. Tel, 6a2-5791022,<br />
Fax 662-5611645<br />
Abstract<br />
CAMBODIA, A NEIGHBOURINC COUNTRY OF THAILAND WHICH STILL<br />
HAS PLENTY OF I'ILD FLORA AND FAUNA SPECIES 16 VELCO}IING<br />
THA] SCIENTISTS TO JOIN THEIR STUDIES ESPECIALLY WILDLIFE.<br />
CROCOD]LE IS ONE OF THE MOST POPULAR SPECIES THAT THE<br />
CAMBODIAN INTERESTED IN ITS ECONOMIC AND CONSERVATION<br />
VALUES.SINCE INDOCHINA AND VIETNAM WARS' NO oNE fNOitIS<br />
ABOUT WHAT I{APPENDED TO CROCODILE IN CAHBODIA. ONLY<br />
IIATCHLINGS I{ERE BROUGHT FROI{ THIS COUNTRY EVERY YEARS.<br />
AI,L OVER THE WORLD BELIEVE THAT THOSE ANIMALS CA}IE FROM<br />
TIIE WILD. AFTXR, OUR VISITING TO CAIIBODIA. WE CAN SHOI{<br />
TIIAT CROCODILE FARMING IN THIS COUNTRY ]S A I.IAJOR, SOUR,CE<br />
OF HATCHLINGS AND SOUE EVIDENCES TO CONVINCE US THAT<br />
CROCODILES IN THE UILD ARE PRESENTING. FURTHER SURYEY<br />
SITOULD BE CONDUCTED IN THE NEAR FUTURE.
Introduciion<br />
99994y.!gq siaoensis and glgj:ggy.lgg llllgjlgg are<br />
Llro !laior crocodili an species endeoic in south-east Asta<br />
region. These crocodilia.ns are hiEh in conservatioD and<br />
econoDic values. AccordinE to over exploitation of natural<br />
resources; huntilte, ftollution 8nd dosLruction of habitat<br />
eLc., lead to extinctio$ of nany species' crocodilians r,lill<br />
be extincted soon in the near future if e do not have a<br />
good and strong conservat,io[ policy-<br />
canbodia one of the hone range of these two croco-<br />
-dilians species which still has both populations in th€<br />
lrild and in captivity should be a Eood place for conservatrott<br />
of these endaDgered apecies. Because of llars' no infor'[&Lio$<br />
cotrcerning to crocodlle is herard fron lhis country' we only<br />
knor,. ihat hatchlings cone out of canbodia every years through<br />
Thai-canbodia boider '<br />
Ir llarch 1992' 8. group of wildlife acienti6is con-<br />
-sisted ol A[erican and Thai uere invited to visit caobodia<br />
iu order to coperate with then in rrildife research' crocod-<br />
-ilie6 alere ote of a very interesting wild species to be<br />
6tudied especiallv surveyind of population in nature and<br />
estabtished of nanageneDt P lan.<br />
Due to a 6hort period of 6taying, we could collect<br />
eone dat,a by interviewing of Eovernnent officers, farners<br />
aud otber autborities. Then nany up date and useful inforn-<br />
-ations atere brought back aDd released outside thi6 country<br />
for t,he f irst tiDe.<br />
t))
66<br />
Ui [d crocodiles iD ceDbodia<br />
very lltte infornations concerui'lg Lo wild croco_<br />
-diles in Caobodia uas knosn. sone useful infolnatiorrs were<br />
obtained by inlervieuing of governnent officers and. crocodile<br />
farners. As ve ktteu that two croco
A fei,, big farns developed there nanagernent into a modern farm.<br />
They used semi-artificj.al incubation of eggs by incubating them<br />
in artificial nests which vere ginilar to natural one. Nesting<br />
naterials cotlposed of dried leaves vegetations and mud collected<br />
from natural habitat of crocodile. Tenperature and hurnidity rtere<br />
controlled by pouring of vater on nest and checking tenperature<br />
tlJice a day bt inserting of lonq thertloneter into nest until<br />
reaching eggs level. Incubation tenperature was about 30oc and<br />
period around 68-78 days,<br />
In 1991 Phnon-Penh farm had 500 eggs uith 75 percents<br />
fertility. They got 300 hatchlings and survival rate was 95<br />
percents.<br />
Sien-Reap provinciat farn produced 1,500-1,8O0 head of<br />
hatchlings every year. Hatchability about 64.5 percents.<br />
Hortality rate of hatchling in the first year around 20-30<br />
percents. (Table 3).<br />
Ton Ley sap, a big lake is an excellent food source for<br />
crocodile farning. Because of plenty of fresh {ater fish, aI1<br />
carnbodians fed their crocodiles with fresh nater fish. In one<br />
mediun size farn, they fed 30 crocodiles with 20 kilograrn of fish<br />
every 2 veeks.<br />
croqoilite FaniDg in caDbgatia<br />
crocodile farning in carnbodia has been started since<br />
Canbodia !'as occupied by French in 1945. Most of lhe farrns<br />
localized around a big fake name rrTon Ley Sap'r which is one of<br />
the largest natural freshuater lake in the world. The oldest and<br />
biggest farn was in siem-Reap provj.nce.<br />
After Vietnan var, in 19?5 Pol Pot government ruled<br />
Canbodia. They collected all crocodiles fron private farms<br />
together and put in one farn in siem-Reap rthich be cones as<br />
provincial farn at this nonent. This place was used to be a<br />
hunan carcasses disposal by feeding to crocodiles.<br />
wtten Pol Pot governnent went down, sieh-Reap provincial<br />
crocodile farn was turned back to be a real crocodile farm<br />
again. By assistance fron Cuba, Cambodian staff was trained in<br />
cuban crocodile farrn for 3.5 nonths. Today there are about 500<br />
crocodile farms in canbodj.a. (Table 1). They keep only fresh<br />
water crocodile (crocodvlus si-arnensis). we can classify these<br />
farn6 into 3 classes according to size and lnanagenent.<br />
c1a6s 1. srnall size, snall number of crocodile, 2 to<br />
20 heads, keep in pond or wooden cage.<br />
cla6s 2, rnedium size, 20-7o heads, keep in social- pond,<br />
class 3, large size, over 10o heads, keep j"n social<br />
pond.<br />
Cta6s 1 This class rnay call fanily farminq because of small<br />
6'7
68<br />
size and nunbel of cr.ocodile. Cambodian villagers keep 1-z<br />
pairs o{ breeder sl, l.he baclr of t,her'e houses. llost of thexi<br />
siLuated oD the river bank irr,d lal.:e l'hich ir; a good source<br />
of ltater and food supplt. Sone .rillager:s rrho live on boat,<br />
they preferred Lo keep crocodiles iD nooden cage thal can<br />
float in vater around l,heir boats. ost. of the faros in Can-<br />
-bodia are in class 1. This class of farn usually sale their<br />
hatchlitrg every year. There are about 2OO of class I farn6<br />
which is a najority of crocodile farns.<br />
Class 2<br />
1ake. crocodiles qat.hered in social pond nade of |!ud and<br />
cenent. Nesting pens are provided for breeding porposes but<br />
for raising or holdi[g purposes they just ra.ised tben and<br />
soId.<br />
clas6 3<br />
These farns a.re not go closed to water. river and<br />
Farn 'rhich is lrig in size and nunber of croeodile.<br />
Usually more thao 10O heads. Thoy k('!)t, breeding sl,ock in<br />
social ponds and provid.ed per[6.nenL nestirrg pens,<br />
Near'ly all biE faros produced and sold batching<br />
out to broker for export, There are only 2-3 big f a.rns in<br />
caDbodia. (TabIe 2)<br />
Ninety percents of crocodile farms lrere operated<br />
ilr the old fashion ; poor drainage and hygiene, very linited<br />
space, no appropriate data recording, high nortality rate<br />
and survival rate of hatchling and nulritional problen6.
A fev big {atns developed there nanaAenent iDlo a nodeln<br />
farn. They used seni-artificial incubation of eggs by<br />
incubat,ing then in artificial nests !,hich I'ere sinilar to<br />
latura] one. NestiDg oateri:Lls cooposed of dried leaves<br />
vegetatioirs and mud collected frotn uaLural hatritat of cro-<br />
-codile. Teoperature aDd hunidiLy !,er'e conlrolled by pouring<br />
of uelLel' oll nesL and checkiog tenperature Leice aday by ins-<br />
erting of long thernooeter inlo nest until reaching eEgs<br />
Ievel, Incubation tenDerature vas about 30 _c and period<br />
aiound 68-78 days.<br />
In 1991 Phnom-Penh farn had 500 ege6 with 75<br />
percent,s fertility. They goL 30O hatchlitrgs arld survival<br />
ral,e was 95 percents,<br />
Sien-lleap provincial farn produced 1,500-1,80o<br />
head of haLchlings every year- Hatchability about 6{,s<br />
percents. Mortality rate ol hatchljlrg iII the first yeai<br />
around 20-30 percenls. (Table 3)<br />
Ton Lo) Sap, a bi{ lake is an excellenl foo.l<br />
source for crocodile farning. Because of plenty of fresh<br />
water fish, all Cal0bodians fed their crocodile:; !rith fresh<br />
wat,er fish. In ooe nediun size farn, they fed 30 crocodil.es<br />
nith 20 kilogran of fish every 2 reeks.<br />
69
70<br />
Crocodi les l{anagenent in CaDbodia<br />
Matragenent of crocodiles in canbodia is under<br />
contiolled by Ministriy of Agriculture. Two offices of this<br />
oitlistly involved, Fishery departnent is incharge of captive<br />
clocodiles while l-orestry departoenL takes care of wild<br />
crocodi i les .<br />
captive crocodile or crocodile farning is conlro-<br />
-lled. by liishery law. The re€ulaLion is bhaL; some'one rho has<br />
crocodile in captivity nore than 5 heads nust register their<br />
farn and crocodiles to local Fishery office or Fishery depar-<br />
-tnent in Pltnotr-Penh.<br />
Export fee for live crocodile nostly halchliDg is<br />
3,000 Reals (canbodian currency) per head uhich is equal to<br />
6 U.S. Dollais, ExporLer [ust pay to governnent, Prohibil o{<br />
wild crocodile hunting is also incllded in Fishery lau and<br />
enforced by Forestry depart[ent and Fishery departnent. Nov<br />
bunting of crocodil.e is decrased because any illegal busiuess<br />
Dust be serious punished. No vild crocodiles survey and nana-<br />
-genelt p18n ever done in caebodia.<br />
crocodile arketitrg<br />
Local narkel for crocodile in canbodia is quite<br />
aaturaied because they all keep only breedels for producing<br />
of haLchling6. Al1 hatchlings are exported and the large6l<br />
narket i6 Thailand. Then value of crocodile i[ C&nbodia
clepends on denand of crocodile6 itr Thailand.<br />
In 1990 Phnon-Penh crocodile farn sold 1 nonth<br />
old hatchling about 2o0 U.s. Dollar6 per head, in 199-<br />
price increased to 30o U.S. Dollars becauoe of crocodile<br />
farni[g in Thailand r,ras expanded rapidly. But this year,<br />
1992, drop to 150 U.S. Dol1ars.<br />
Captive tloro crocodiles usually caoe to Thailand<br />
throuEh 2 rout,es; Port of Co Cong and Battanbang border.<br />
Registered farns usually export through Co conE but nost<br />
fron s[a1l unregislered fatns are sDugg]ed via Thalland-<br />
canbodia border vhich is very long and occupied by differ-<br />
-etrce Cambodian €roups,<br />
71.
'72<br />
corlclus ion<br />
Caobodia should be one of lhe test place in ihe<br />
world for crocodile conservatiott especiaily c.eianensis<br />
becauge Lhey already have population in the IJi1d, appro-<br />
-priate habitat, captive t'reeding operations and lau to<br />
protect then. But they are still lacking of lnfornations<br />
and [anagenent p.Iannitg. we are looking forward Lo have<br />
sone organizations to conduct and sssist caDbodia to do so<br />
i! the near fuiuie. Then ve can save crocodilials itr canb-<br />
-odia ard this reEion of the world.<br />
Acknorledgerent<br />
we would like to thank Eleaner Briggs for her<br />
kind assistance in interviewilg and taking pictures ai sien<br />
Riep province and also crocodile Ma[agenent Association of<br />
thaila[d (c.M.A.T.) who sponsored oe to do this gurvey.<br />
1.<br />
RefereDceg<br />
Canbodian Jurists, A <strong>Group</strong> of. 1979. People Revolutionary<br />
Tribunal HeId in Phnoo-Penh for The Trial of The Geno-<br />
-cide of The Pol Pot-IetrE sary clique Docu[elts. p.Iv-<br />
22?<br />
chu. Po seng. 1992. chef du bureau contentieux, Fishery<br />
depart[ent, Phtron-Penh' Pergonsl conn.
3. Han, Ly KiD. 1992. Dilector of Fishery departneDt, Itj.nt-<br />
7.<br />
-stry of AEriculture, Phnon-Penh, Personal con[.<br />
Taylor, E.H. 1970. Tuitle6 and crocodilians of Thailand<br />
and adjacent waters, with a synoptic helpetological<br />
bibliography. Univer6iLy of l(ansa.s science Bulletin.<br />
LAlrrence.49787-779.<br />
Thouk, Nao. 1989. A Lesson in <strong>Crocodile</strong> Fa!'ning. sien<br />
Re&p provilrce crocodile faro.<br />
ToDn, chheng l(in. 1992. crocodile feeding ceDter,Phnotr-<br />
Penh. Personal coon.<br />
webb, G.J.w.. s.c. l.lanolis and P.J. whitehead. 1987.<br />
Wildl.ife l.Ialrageeeot: <strong>Crocodile</strong>s aDd Alligators. Surrey<br />
Beatty and sons, chipping Norton, Australia.<br />
'73
Talle 1<br />
Diatribution of Crocodil.e Farra<br />
Prov iDce<br />
1.. Phno|-Petrh , private farr<br />
i! Carbodia, 1992 *<br />
2. Sietr-Reap, Governnent and private faro<br />
3. Battanbang, oovernnent and private farn<br />
4. tronpong Chatrang, Governnent and private farn<br />
Total averae c<br />
nuDoer<br />
130<br />
300<br />
491 farns<br />
Chheng fiio Tonn, Crocodtle Feeding CenLer, phnon penh
1. PhDor-Penh<br />
2. Sie.-Reap<br />
Populrtion<br />
3. BaDteay l{eanchey<br />
4. Batta.batc<br />
5. Pursath<br />
6. Korpong ChaDaDg<br />
7. KorpouE Sor<br />
Registerod<br />
Ptovince<br />
loLat<br />
Po Se[g Chu, Chef du<br />
Dgpartaent<br />
TEDI. t<br />
of C8pilve<br />
to Fiahery<br />
in 1992 |<br />
CrooodllGs<br />
Departrert<br />
nu&ber<br />
2,4O8<br />
1, 800<br />
1,62O<br />
bureau Contentieux, F i shery<br />
32<br />
70<br />
't5<br />
gJlllll heads
Table 3<br />
Nurber of Eatchlirgs in 1992<br />
Province nunber ( ap"rirox. )<br />
1. Phnor-PeDn 250<br />
2.. Siea-Be8p 2, 500<br />
3. Bautarbarg 1,250<br />
4. trotpong ChatraDE L,20O<br />
Total 5, 200 leads<br />
* Ky Leant Hak, Factory anager, UK International co. , Ltd.
CONDflON FACTOR OF Caiman cr temporary channels = fresh<br />
water ponds. Condition factors were siguificantly different in relation -to body size of<br />
caymans from salt water ponds, rivers ard fresh water ponds. The young caynans<br />
showed highest condition factors ir salt water ponds and the big caymars had highest<br />
values in rivers,<br />
77
78<br />
COMPOSMON AND ENERGY VALUES OF SOME FOOD ITEMS<br />
INGESTED BY Caiman crocd,iha yo.care lN TI:[E<br />
BRAZILIAN PANTANAL REGION<br />
S.A Santos and M.S. Pinheiro<br />
Rua: 21 de Setembro, 1880<br />
Caixa Postal 109, Corunba, MS,<br />
Brasil. CEP 79300<br />
Caiman crocdilus yaccre is found in the Pantanal region in Brazil in various<br />
habitatq including rivers, temponry charnels, fresh water ponds, salt wster ponds,<br />
marsh and artificial roadside ponds. The stomach cotrtents of cayman of these<br />
habitats was collected and identified the loPest taxonomic unit feasible. With the<br />
objective to determine the composition of foods ingested by caymans, the most<br />
important prey were collected in different habitats: 1. Hemiptera (Belostomatidae);<br />
2. Coleopten (hidrofilidae); 3. brvas of tus€cta (odotrata); 4. Mollusca<br />
(Pomoceae); 5. Crustac€a (Trichodac9lidae); 6. Pisces (Calichthyidae); and 7.<br />
Amphibia (Pseudidae). The composition of thes€ componetrts (dry matter basis)<br />
were: dry matter, 29.6,37.9, 19.6,39.2,22.7, ?5.6 ard, l5.3Vo, crude protein, 64.1,<br />
65.4, 61.1, 18.8, 65.9, 64.2 ad 67.I%; gross energr, 5.4, 5.1, 5.8, f3, 4.5, 4.8 and 4.5<br />
tcafkg; calcio (Ca),0.25,0.?5,0.3, 24.9, 0.3,7.8 ard 4.67o; phosphoro (P) 0.6, 0.5,<br />
0.45, 0.06, 1.2, 3.5, ard 3.2Vo, resp€ctively. It was observ€d tlat most prey ingested<br />
by cayman had a high protein and energetic ralue, but improper Ca to P ratios<br />
according to body chemical composition of Cc yacarc of 2:1.
STATUS OF ORII'O@ CROCODILE POPUI'\TTONS IN<br />
SOXE L@ALITIES ITI IgB VEI{EZUEIIW LLAXOS<br />
Andr6a EIov Sei-ia-s. I,I{ELLBZ. X€aa de C.vacaa, Guanare,<br />
Portuguesa. VoDeruela.<br />
Since l99O f have b€en conductir{t suave:rs in several<br />
localities in the Veneruclan Llanos, to aaresg the statug<br />
of the Orinoco crocodile populations. The .ore i.Dortant<br />
of these sites are the Co.jedes and Sarare rivers, in<br />
Cojedes state. These sites rere previously surveyedr fror<br />
198? to 1990, by Jos6 Ayarzatiiena, *ho estirated e<br />
populetion o? up to 50O non-hatchlin* caocodiles scatteaed<br />
in branches, artificial channels and srall tributaries of<br />
these rivers. During 1991 and 1992 I hsve visited three<br />
tides Caio de Agua, one of the branchee of the Co.iedes<br />
river. Eighty three non-hatchling ctocodiles were sighted<br />
in that locality, no less than 13 of ther adults, l.{y dats<br />
do not indicated a decline respect to the nurber of<br />
crocodiles observed in 1987 by Jos6 Ayarzagiiena in the<br />
sa[e place, but the lost inportant threat on the survival<br />
of this popul&tion (t.ater pollution) re.aids the sane. Our<br />
efforts should be directed to pao.ote a plen lor the<br />
protection and full recovery of the surely aost dense, snd<br />
al8o probably largest, Orinoco crocodile population in the<br />
corlntry.<br />
Another locality I have visited fror 1990 to 1992. is<br />
Tucupido Rese?voir, in Pottutuesa state. Before the<br />
tucupido River was darred, in 198?, several authors<br />
reported an Orinoco crocodile population of a little rore<br />
than 100 individuals. In twelve visits to the reservoir at<br />
least 8 crocodiles have been sifhted. All but one of ther<br />
adults. The only ,iuvenile seen (and captur€d) ros borDe<br />
before the da.n I'as constructed lrhich teans th&t there has<br />
not been recruit.ent of Orinoco crocodidles in the<br />
reservoir, r4ybe due to huaan depredation of nesta.<br />
trinally, the Anaro River, in Barinas atatet t.as<br />
visited in JaDuary 1992. Anecdotal iltforration indicates<br />
that there is a srell population of Orihoco crocodile<br />
there. Fisherren depredate several nest of th€ specles<br />
every year. The habitat in this river is, horever, shosr<br />
iDtact. The possibilities to use the Anaro river to<br />
relessed ceptive reared crocodiLes should ba serlously<br />
congidered.<br />
79
RanchtnE Crocoglles ln !.he Hlnslayan Waterd gf Nep91<br />
lej Kuear Shreathe<br />
Central Depertoent of Zoology<br />
Trlbhuven Unlverelty<br />
Klrtlpur, Kathoandu, Nepal<br />
Absttdct<br />
Numbers of Mugger and Charlel crocodlles aie dltlndllng o!,1ng to ovet-exploltatlon,<br />
po1lutlon and habitat oodlflcatioa by pover dans. Rsnchlng Pos€tbtllttes of<br />
crocodLle tn rl1d and Ecerlc tlvels by slmulatlng nsturel rlverlng hsbttst le a<br />
nost promLslng task for Long-terh conservatlon of crocodlle Bene pool ln llll|alaya<br />
natursl forktng chennels and oxboss ld the Karnall rlver ney be best utl1lzed<br />
for creatlng crocodlle rsnctl. A novel nod€1 of crocodlle rsnch to b€ developed<br />
tn f.arns11 rlver ls presented. The edvantages of rauchlng to the trad{tlonal<br />
fernlng or crocodlle husbandry 13 h1gh1lghted.<br />
Inttod.ucltgn<br />
The crocodiles are best knoon reptile con6ldered elther threaten€d or<br />
enalangered all over the vorld. A volunlnous volk exlsts otl ecology, behavlour<br />
crocodlles (mrttakar and Bssu 1988' Shrestha 1986r 1990, Mtslrre and Maskev t98l)'<br />
There ls e scsnty lBfornslion about crocodlle ranchlng and tlrelr mengSenent 1n<br />
the wtld. In thls Paper feeslblllly snd deslrabtl{ty of ctocodlles ln 6cen1c<br />
$ild rivere of Nepel are dlgcussed to tbrot 1lght o! the need and oPPortuolty<br />
of such scElvltles h the netural hebitat dtsplaced by daoa' Durlng recent<br />
yeals Elderiilge 1985' suni'elo 1973, l'{ecNell 1975' Kl$gslerd 1985, Ha11er 1990'<br />
lleller aoil Baer l99O conpleted thelr ldea of DodeUtng oetute for beneftts for<br />
rtldltfe and nas.<br />
There ale a nuDber of pros and cons concelnlng the rearlng of crocodlle6<br />
specles ln ceptlvlty. IiI general cePtlve breedlng end reerlng programres 6te<br />
lll.-coavhceil beceuse stllnals 1o6e irlld nature. One elo of caPtlve rearlng<br />
crocodiles ls to eupPly enlosls to zoos end 'Jtldltfe parksr thus avotdtn8 croco-<br />
d11es beioa taken froD ttld. the Dore zooa that have crocodlles' the greater<br />
rhe auillence that !.'tll becone farlllar wlth theE and thelr p118ht lesdlng to e<br />
greater synpathy for thelr cotroetvatlon ln t1ld. the othei baln teason for<br />
captlve rearlng ls for te-lnttoductlon of crocodlles to the !tt1d. In s develop-<br />
lrig couutry llke Nepalr the probletrts of captlve breedl$g and rearlng ere qulte<br />
allfferent and therefore Po3s1bl1tty of crocodlle tdnchlng ls conteoplated'
Concepjal Desisn<br />
Mugger:s and chartals are lrell known crocodlllen of the Hlmslayan rlvers<br />
of Nepal, Fe' reptlles of the Hinalsyan rlvers lllustrate lntftnslc of sdapts-<br />
tton of crocodlles better than tbese t\ro crocodiles. The ctocodlle6 have<br />
decllned ouch due to ecologlcel chenges 1n wsternays broughl by balrier eflecta<br />
of dans Inroads of pollutlon and harnful flshlng practlces. At nsny places rlver<br />
cou.ses have changed and nestlng beds hsve been destroyed, Destructlofl of nest-<br />
1ng areas afld resultaat falLure ol nestlng have affected hdtchltng resourcea<br />
greatly. If the natural breedlng habttsts of crocodlles Eoea urunonltored,<br />
vsluable resource ot Nepsl wlll become extlnct. Crocodlles do rlot bteed $e11<br />
ln s closed systess of lnpoundoents elthougtr they can grow to naturlty there.<br />
They need free-flovlng snowfed and rain-fed water. Thelt nestlng sltes muat<br />
have good-slzed pools snd rsplds, 6and-bars and gravels. In a closed systen of<br />
crocodlle farEs, a1l- these basLc habltat needs sre not neti thetefore' crocodtlee<br />
refuse to breed. An lonovatlve aen concept of taDlrg trt1ld ltlnaleyen rlver for<br />
creallng open waier' ranch ceo be evolved. In osay ptlstlne rlvers of Nepel Pools,<br />
back I'ater replds, sand baflks eod prononotorles of rocks snd stone habltst are<br />
destroyed by huuan encioachuent snd cteellon o! polret dshs' To evolv€ sucb<br />
orighal habitsts takes aeons of tlne. As a coDpensatlon to lt senlneturol<br />
crocodlle ranchlng statlon cas be made by dtverlIng orlltEal rtver course ot<br />
channel at deslreble spot, ln rlvers of Nepal 6uch ldea1 lanch sre hany and<br />
csn be utlllzed vlth lllll.e effort. The ranch so created may act es crocodlle<br />
and fish sancluary, buffer zone or escape ared and help6 to relse and releaae<br />
young crocoallles year efter year. Many oxbons and d1ver61oo ol lrrlgatlolr<br />
facllitles can be osde so ss to create e fullfledged tlverlne ranchlng spoi,<br />
where nlgratory crocodlles csn be ranched year afte. year. lhls w111 greetly<br />
help to cotrserve crococllle lesoutce6 anal brlog bick depleted crocodlle 6tock<br />
to origloal level- of abunderce.<br />
the open-ltater lanchlng eysten alns at al'l habitst needs and hes adventege<br />
over the tradltlonel<br />
t'Put<br />
aad TakeI gystens. In thls systebr Eature breedets<br />
are sublecte.l !o breedlng and resrlog thelr young theoselve. Crocodtles could<br />
be rslsed ln ranch to a yesrllng stage oo a nass scale and releaeed back to the<br />
river to spawa llrto nee genetstlon of crocodlle after three yeers' Thls effort<br />
,11.1 rebulld crocodlle population ln the rlver sod counterdct forces of ovet-<br />
exploltatlon,<br />
Thls aevt systen ls ceUed on open water "Ralse and Relesse" systen.<br />
as this syste0r enhances cont!o11ed breedlng of crocodlles and he1P6 to Pteoetve<br />
gene pools or rste stock of the nugger aIId thatlal<br />
crocodlleg'<br />
81
82<br />
j]ul.ecrtves of Rraochlng crocodiles<br />
Now lhat scleotlsts all over the world are aware of precArlous condltlons<br />
of the existence of crocodlles, sclertlsts ln Nepal hust strrdy nrays end Eeans of<br />
thelr pxopagation snd populstlon growtlr, Thls cerr be done by ranching. the<br />
coaceptual deslgn of crocodlle ranchhg should be based on i\ro conve tloiral<br />
approach systems, ecology and populsElon ecology arld behavlour. Based o$ ny<br />
studlea of clocodlles, tn the Ksrnell rlver (Shreslha 1990), I have cone up<br />
wlth the fouowlng constluctlve rsnchlng, rehabllltatlon and enbanceh€nt pro-<br />
gramle!.<br />
The objecttves of the cr:ocodtle rsnchlng proBrame are! (r) ro save<br />
:ienalnlng natulal populatlon, (2) to naxlslse natural recrultnencs through<br />
"grow and relesse techn1que6", (3) to propegete alrd re-stock crocodlLtans ln<br />
areas whele tbey once occurred and the potenttallty for thelr survlvel ls sttll<br />
exlstlng, (4) to lnltlate natural as well as captlve breedlng, (5) to enberk<br />
on research {n the dlflerent a€pects of the bloloay snd nanagement of the<br />
crocodlllansr and (6) to produce tralned personnel et dlf!e!eflt 1eve16,<br />
Crocodlle Ranchlnq Areas of Top P(torltv<br />
In Royal Bardla Natlonal Park, toprpst prlorlty la to be glven to perfect<br />
the rrgron and reledse'r technlque fot rlver habltatsl Lt 16 llkely to b€ changed<br />
by hlgh da[ and result 1n rdtld populalton urgertly. Sone of the lnportsnt<br />
aspects to be coveled are: (a) lnterp!etatlon of the vsrlous d6ta collecred<br />
durlng flelds survey and census, (b) ralslng wlld crocodlle ln seBlnstural<br />
condltlon. Supply of llve llsh food ls ltDportant, so gene flsh found lrl the<br />
rlver ls to be culllvated In the hatchery, (c) rearlng young crocodlllans In<br />
senlostural wllderness lncludttrg lood requlrenent and food converslon lrlth<br />
growth studies, and (d) behavloulal blology lncludlng re!'roductlon, ther.0ro-<br />
regulatiofl, feedlng, orlentatloD and locoDotlon In senLnatursl hebltet of<br />
crocodlle Ranchftic stetlon Eor to Estsbllsh<br />
Fundanenlal detells of the proposed crocodlle ranch eiet there are dany<br />
feeder rivers Jotnl.ng tbe Karnall rlver vlth lleny nestlng Brounds. Nestl.ng<br />
beds of Karnali river ele located nearby Bardla Day be se!.ected for thls purpose.
i-'<br />
\/l<br />
'I '-'1<br />
,, NI'I'/rI,<br />
'\M<br />
-q^<br />
t-x6^r<br />
l / \<br />
\9lTy<br />
....-..'-.<br />
KATARNIA GI]AT<br />
fj;:"<br />
,l<br />
._t<br />
q")<br />
tk<br />
o.rirl cttlt<br />
83
Ihls atea ls 1dea1 because htstorical crocodlle stocktng pools sre located very<br />
near the Karral.l rlver and lts feeder streams. The gorge sectlon of the Ksinslt<br />
liver ls an ldea1 slte for collectlon of crocodlles uhlch have been used by us<br />
for collectlon of mature crocodlles. In entlre stretch of the Khorsha branch of<br />
rhe Kalnall rlver up to 3 kns upsttean, there prevstl ldesl envllonnental condt-<br />
tlons for crocodlle such as grsvel beds, rater f1ow, oxygen, wstet quallty and<br />
lt 1s adBlrably suited for breedlng. If thls strean 1s changed lnto artlftclal<br />
crocodlLe runnlng channel ln conlunctlon wlth an exlstlng crocodlle faxm, 1t<br />
would certainly help the nass produetlon of crocodlles ln senl-natursl condltlon.<br />
Crocodlles renchlng would represent a vl91b1e step in lransltlon from s huntlng<br />
ta farnlng econony in the Elnslayan waters of Nepa1.<br />
Pdpulstlog<br />
In lhe proposed open-wster rarchlng sy6ten, rnuch depeods upon the hydro-<br />
biologlcal regl$e of the liountaln rlver, such as flood and drought. The cbangtng<br />
rlver conditlons affect abundance of crocodlles for good 6nd evll. Such seasonal<br />
verlatlon l1es beyond the conlroloi'nan but can be nsnlPulated to 6orne extent'<br />
Other factors howeve! are wlthln our power. The baslc tenet of crocodlle tenchlng<br />
ls that the crocodlle populalion oI each rlvet and feeder strean must be treated<br />
es seperste breedlng unlt sanctuary and for eech a sufflclent numbet of adults<br />
oust be allowed !o escape ln clesr, undanaged envlroonent. If thts ls done year<br />
after yearj gratlfylng surges of ctocodlles u111 appea! h numbers sonetlnes<br />
exceedlng past runs.<br />
<strong>Crocodile</strong>s lsnchlng caD be achleved by Etocklng youngllngs ln natural earer<br />
in the same Benner ss hes been done ln case of deer ln the USA' Ranchlng croco-<br />
dll,es 1n open lrater ri1ll be better than farnlng in enclosures both aesthetlcally<br />
aDd econolnlcalLy.<br />
t iker,rlse, the eggs fron female crocodiles 6te collected fton Nerayani rive!<br />
and subjected to lncubetlonr hatched and toung are reared to youngerllog stsge<br />
la speclally deslgned llverslde hatchery near Royel' Chltoan Ndtlonal Psrk. The<br />
youogll[gs 60 produced sould be relesEed bsck into rlver to 8ro!t<br />
furthei and come<br />
back to deposlt egg ln the rlvel vhere they tere born' Expetleflce of Past decades<br />
wlthln crocodlle fsts ln Chltwan has sho n that feoale crocodlles glor,t to neturlty<br />
ln stagnant water of pond but do not develop thelr gonad to bteea glccessful1y.<br />
HofiDonal lnductloll 1s the Dost useful nethod of cspt{ve breedlng'
4<br />
F]<br />
4<br />
E<br />
H<br />
F: '{<br />
Ei O.<br />
z<br />
z<br />
H f.{<br />
Y}!{<br />
VE<br />
!iB<br />
a<br />
H<br />
(<br />
$,#gc{
gilielgne !9t!geg_crsc.9g4e Egnlhrl8 gtd_IaIg1lg<br />
In crocodlle ranchlng, as opposed to fsrnlng, crocodlles are kept h<br />
captlvlty for early part of thelr ltfe. Crocodtlesr (ehlch use htSh ground of<br />
rlvers bul spenal nost of thelr 1lves ln ft h;e a strong mlgrstory lnsttrct and<br />
are well-suiteai for rsnchlng. Mugger and Chsrlal crocodlles are conflfled lo<br />
ranching statlon untl1 they teach yearllng state (sbout one yeer old) et ithlch<br />
tloe they are relesseil for thelr Journey !o the llver6 where they w111 stay end<br />
grov to nlaturlty an
References<br />
Elderdge. N. (1985). Unflnlshed synthesls. Oxford Unlverslry press.<br />
Ha11er,_R.D. (1990). Integtstlng crocodlle fernlng lnto on exlltlng llvestock<br />
and Ttlapia !arn. tlabere ye Baobab. Daobab. iaro N€us 59/12.90. Monbase.<br />
Halle!, R.D. and Baer, S. (1.990). Integrated Aquaculture SyBteD. Ttlapta,<br />
crocodile and rlce cultur:e workshop on Aquaculturet ICi"AnAfi. Maotl;,<br />
Pb111pplnes.<br />
Klagsland, S.E. (1985). Modelllng Nature. Urlverstty for Chtcago press.<br />
Msskey, T.M. and Mlshr6, l{.R. (1981), Conservetlon of Chartal in Nepsl. Inl<br />
Wlld 1s beeurlful. Edlted by T.C. l,taJupurla, r.ethtoandu, Nepsl.<br />
MeNeil, W.J. and Belly, J.E, (f975), SallIon rsncherB roanual. flsherle€ Centre.<br />
Auk. Bay. Flsherles Laborarory publtcarlon.<br />
Shrestha, T,K. (1981). Ecogeographlc dtslrlbutton of reptlfes Ln Nepat. In:<br />
Majupu!1a, T.C. ( ed.). wl1d ts Beautiful. Introductlon to Fauna and<br />
Wlldlife of Nepa1, 142-146, Lashker.<br />
Shrestha, T.K. (1990). Status, ecology, conservallon end bansRemen! of crocodlles<br />
ln Hlmalayan rlvers of Nepal, pp. 332-349. In Hioaleyer Envlronnent, Re6oulcea<br />
and Developnent (N.K. Sah, S.D. Bhattr R.K, Pandey ed6.) Shree Alnorih Book<br />
Depot, Aloorar ladia.<br />
Su&re1o, I.S. (1973). Notes on turtle rsnchlng at Tldung Islsnd, U.rlversltes<br />
Naalonal r l-3, Jakertd.<br />
whttakar and 3asu, D, (1982). The aharls.l (qEy141q g€ngettcus_): A revtew,<br />
Bonbay Nat. HisE. Soc. 79 (3), 531-548,-<br />
87
88<br />
INOIAN MUGGER<br />
Ctocodylus palusttis Lesson<br />
(Rootilia, Crocodilia)<br />
TERBITORIAL RESOURCE.PARTITIONING ANO<br />
ITS IMPLICATIONS IN SANCTUARY MANAGEMENT<br />
1. Suoocry<br />
2. lntroductlon<br />
by,<br />
LALA A. K.SINGH<br />
COTJTEIiTS<br />
2.1 . A problor ln arocodll. r.nrgr|lnt<br />
2.2. T!r!dto!r..l bshcvlour<br />
?.3. Prgelnt rtudy<br />
5. Glols.ry ql t elalnglogy<br />
4. 6tudy qrac<br />
5. flat.rialc Erd lqthod!<br />
5.1 . SrrEd 1n9 cncl,ocure<br />
5.2.5tudy lniBEIg<br />
5.5. Data sht3t<br />
5.tlo Drta coll.ct,lon<br />
5.5. Data lrtrsps!tat loh<br />
Fldcllty to uate!<br />
Fldsllty to basktrE 8lts<br />
Colpatiblllty cod doqtoEncc<br />
Resoulco utllr,8.tlon and toaal,toalallty<br />
6. R..ults<br />
7. Ol,.cuaalon<br />
E. Ac knoalodg<br />
€aont r<br />
9. natrtrEa
In 3 6!:rup<br />
1. 5 U rl lt1 ri il Y<br />
cf tll,t oal,€ and ?our femalo muggcro<br />
Gfgg-9s!!.lrl tglggllil) hi.!!archial dominency lEadirE to<br />
rsgourco purtltloning u,sro ob9€rvad in h19h6! incidencss of<br />
occupylng the uat€r, favoulcd basklnS spot(s), Inost 6uitab16<br />
nosting spctr and maltitainlng cootacts urith namber6 of tho<br />
oths! grx. Th! dooinant flnal. !€strictsd th6 use o?<br />
avsllable t!soulca by oth6! f€nals6. Recraslv6 froal6s<br />
hcd contact factors lhoUlng norB afflnlty to tho frnsla<br />
eeeond in th! hiolaschial ordor. urhrn nors than ona |iqgg€!<br />
occupisd tha 3aD. ronr of plaf.r.ncc, Partltlonlng of apnc'<br />
occuttcd at a fintr IgvEI anong thg occupant6.<br />
ALl lacasslvs femalEs oholred contact factorg !'itb<br />
oal,as, at lev€ls 44.0-4?.3. Bscauaq of p!.vontloo by ths<br />
dooinant f.ma1r othcr ?6t|aI!s could rd|lotain 'contact'<br />
nostly uith thc racond lc. Thr eaclnd maJ'!t thsrsfdrcr.<br />
had r totct feia Ic-contqct-lscto! of 116.4 .. agaLnet only<br />
97'5 of ths tlrlt oal.. Tht poesr'blllty ct 6a!Ly seos3cenc'<br />
dus to lsproductlvr ov!r-ue! during tho lil6 span of thc<br />
mals s6cond ln th! ordsr of hiqratchlal domlnaf'cy 15<br />
discuased. Th6 soall6et ldeal breeding group oay bs 3mt5tr j-f<br />
6H:6s ls costtr to "* eo<br />
Stghtlngs ucr. tns 6:<br />
ff,i"sfou".i;s. Si3",fn"#1";." " on<br />
u/hen t€op€ratur63 uarE lou and thE nunbsrs of r3lny dayg<br />
uor. tha olnlluo. Activr s€tsctlon gf nosting gi'tost 6vid'nt<br />
rs .trlcl nlattnl. trcr! aoen froo 20-25 dayE beforo sctusl<br />
ncatinq. Adjacsnt nBgting sltqs uelt oqt u8€d by t0'o<br />
89
90<br />
famallg on th. laEr night. A pr.f6r!6d n.sting sit6 u,.s<br />
consletonlly uerd lvary ycar by tho dom!16q1 fdnals. Th6<br />
sltc {ras 6ha!6d uith thE<br />
o n Iy a f t € ! t h a I a<br />
nostlog by hcr sclf.<br />
lcc6Ssiv! fsfla166<br />
p s {t of a feu days froo<br />
In ths uild uherc tood ia oot a Linitlng factor,<br />
t!rrLtosial baskirE spots ld.ntiftrd in tho r!intsa s.assn<br />
can b€ qlt€rad rs a ttandalcl plEctlcc Ef hsbltat [qnlpulatlon<br />
to ctoata . tru patqotlal b.rktaE sitrr Losa!6d. an lltnor<br />
benks of thc habltat. Thls Ectlon by th! |lanagsmlnt le<br />
axptctrd to atdqcr thr tengc of Eovrmont ot tho croc,)dll,o,<br />
cnd thur rlducr the chancqt rf msn-csgcodil, conllict ln<br />
d natulal h.bltrt.
TNTRODUCTION<br />
2.1 . A PROEL€I IN ER{X,OO ILE MANAGE&ENT<br />
Durlng 1975 covernB.nt of Indla coooonc6d clocodj.l!<br />
qonsarvatlon pt.og!ammaa<br />
In vs!ioua stat6s !rlth agsigt6ncr<br />
froo ths Unj,t6d Nations Drvcl,opn€nt programm€, and Food<br />
aod ,lg!icultuE! 0rEanloatLon of th6 Unlt!d Natlono<br />
(F.A.0., 19?4i 8u6rard, 1980). Th. prog!ar c 'r,as ba.6q<br />
an | .gtgr and ral€€a. t.chnlquc. to robulld na!ural<br />
gopul,ctlcna of cracodillans la protect€d .r!.S. lUhil!<br />
!!vis!,lr€ th! |o-ylar old plograqr€, Singh, (aa and<br />
Choudhury (1985) orntloncd thst .lthouih clocodil.. u,r!!<br />
bctto! plotectrd in 20r399 sq.kn q1 19ild[i fe q 16a3<br />
incl,udlng thlrt..n numb.trr of spcclsl crocodilo Banctt,.rl.!<br />
ov.r 8346 cq.kn., th€ Indlan public u.ra still, in ths<br />
Proce€€ sf conplctsly [,!anlng auay s n€gatlva 6!tltud!<br />
tourEJde csocod116!. Slnghr Choudhury rnd XBr (1990) havt<br />
sleo r€ntLoncd thqt ulth the lner.ca! Ln the nunbrlr .t<br />
crocodiIra io .vqi.labl€, alr.ady Bhrunkoo. hsbltatg<br />
s,0ncarn for nuialncr crocadil€s uoa! on th6 Lncroagar<br />
aven though partlculsrly for thr, sdltuatcr c!ocodils,<br />
Crocodvlus ElggE.<br />
Rlth, Slngh .od KBi (1 990) havc<br />
Et!gsscd th. n!!d to tackl! nuj.s6nc€ crocodilos and<br />
!6dqc. tran-clocodils confllct ulth 6u!tablc nariag6D!nt<br />
grogtaDB. ln th. stat. of 0sl,eg..<br />
9l
The ouggsr sr06odll,6, t:!ocodvlu8 Dir]!strl9 is<br />
IJlatlvlly hatelse8 to huoaosrand ts kndsn to hav!<br />
coaxictrd in uato! bodl.s corlnlnally trr€d also by hunons<br />
and c.ttl,€s (iutiitator, 19?4t Achar-jyo and mohspatrn, 19Zg;<br />
.L<br />
Singh, 198-1, and Singh rnd Sagar, 1990)<br />
fnapit. of th. abov! kno'r,l,.dg6 Lt has al,u,.ys b€en<br />
nscrascry lor thr naneg c,ngnt to !6ducr D6n-crocodil,.<br />
contacts und.f th! dlfflcult oltuatlon that thc |l|atsr<br />
bodh8 drclarrd a! crocodil! aenctuorl.! c6anot br<br />
conplctcly trabd otf troo hu|lao actlvltl.r.<br />
Thr nqsd tor thc oarEgsDsnt, thor!?sr!, ia to<br />
rtt'lk! r Conpa.!l!. by*ld.nttfying op€qj.flc muggoI, uon!o<br />
Cb)<br />
'r,j,thin ths aroctsary, (naturall,y !sEtriotlrE tha movEnont<br />
of sild muggcts thtqsgh habit.t nanipulation practlcrsrard<br />
(e) b6 impo;in7<br />
'ho-.ntry<br />
.ocaon and arcaj'ooly vhcn<br />
and sh.r! thc san-saocodllc conlllcts ara most llk!Iy<br />
to occqs. AssordlrEly, ,,t ls gortlncnt to obt.in a<br />
bettrr undrfgtandtng of thq clocodil6s. b6havi,gu! o?<br />
rslte- ftdrtlty. (Lang, 198?t 9278).<br />
2.2. TERRITORIAL gC H AVI OUR<br />
rSlt. tidcllty. La deoonitlEtld from the ablltty<br />
to honr, ae ln the Aorltcan alllgator, Alllaator<br />
olssl.oslprtrnsis (tlulphy, 1982), and in<br />
Crocodvlu! oalust.rlq (stngh, 'l 983bt llhltake! .nd<br />
uJhltaker., '1 989). Crocodilians nay movc ovet LonJ<br />
disLsno.g to r.dch th.lt tiaditlsoal broeding.nd nostlng<br />
grounde, B e ln 3. -g!E19g.ipli9.li1:<br />
(chabstck, 1965) '<br />
cavlalls oa.n6tiquo (5lnghe 1985:p7'l-?3), and c. ,
Foloeu9_ (5. y.ar, psr9. cDon.). ljnder norr€L conditlon3<br />
tho brskirl
94<br />
juvrnilos ba6klnq togeth6r (Saga! and Sloqh, 1990a_).<br />
Although tho dlstanc6s covcrgd !1|Jrs not 6noI'mDus y6L r€srt<br />
!r$fo dor)tr!h Lo $oU!6rt dopofturr tfo|n,rn 6.rrLIL,r qfsUu!1!)u:r<br />
habIt. Th6 g!eg.rious habit may tr!eak auray earIi6! if a<br />
lrndirt4tbed<br />
epacioue(habltat ls availdb1!.<br />
tlrJggs!s trnieh hav6 !6naj.ned t,o!ethsr ovo! m{ny oonths<br />
o! y6atrs ats assurned to havs eEtablighdd th€ir hi€tarchial<br />
oadc!. Und6r euch a si.Luat:on if, s nd!, .nugger le lotrgd'Jced<br />
1t is nornally not tqlerltEd, and th! lssult io fotalfrlgnts.<br />
Exampl,ss hsvo bsan rocorded ai Nandankaoan Biologlca!. park<br />
and Reratllthar both in oalsea, durlr€ Octob€r 1980 and<br />
NovsabE! 1990, rcepcctlvely. Severe flghts hau€ a16,) De€n<br />
!ocordsd at Tadoba in maharashtra undBr si.rnilar situation.<br />
A gtudy conoucted at RaiEtirtha (sagar and 5lrqh,<br />
1992.) shoord that a youngcr bctch of hatchllngs pr€f6rred<br />
to lleain ln tunn6rs or dlsappoarr urhsn subJdcted to<br />
gtou along with an oldlr batch ol Juvrnllo muggcrs.<br />
As a standald practics ln captivo huabandty, young<br />
crocodi,les atE eizs-sorted to ave!t any pFychological<br />
disadvaotags and chansca of otf-fosd uy slou-grouring<br />
Juvcntleel elihough of ths same yrqr of, hatchlng.<br />
.Tcrritorial fightgr a!E g6ne!ally sern vrlth nugg€!a<br />
uhlch ars at 1ei3t tnre! yod!3 old. Cut mrrk:' on tkln'<br />
partlculerly<br />
ne( An't<br />
thef,baeq of tho tall, are ths common outccm'<br />
of such fights. Intlusi.on by a sgcond flrala maif lead to<br />
f19ht and 'c1lck' c serles of courting behaviour durirrl<br />
brs 6d ln3 season (Sin!h, 1983b)'
coomural n6stingr is a behaviorilal accoopli.shmsnt<br />
ll,het€ tr!ritorial hostillty is 0rrni.nrun 3nd ao availablo<br />
n€sLlng srto Ls us€d fur l.rying ol ogijs by severdl<br />
fonolEs. It hs€ bgen recoldsd in spt,cios Lika C. nilorrcus<br />
(cott, 1961), !.<br />
johnstoni (i!6bb, 1ggt) and !. gglgjtr;ls<br />
(Sin9h, 1978; Rao and 5ingh, 1991). Thit Indd,an oujget,<br />
Crocodvlus. odlustrl.s fi\ay b€cona a comrj,{rn,t L nester .irhol6<br />
condltlons !!quirg. In an aroa ot 15 8q.r|. st Hilan Lakc<br />
in Gir National 9arkl Quj6561 ctght negts r!er. lald, and<br />
uithi.n a ehorr 1in. of 20m ot Set,hanur, Tshilnadu thorc<br />
r!€!6 thr!. n.!sts of !. palust!is (8. C. Choudh'JrV,<br />
pers. comm, 1986). Th.r!fo!., al.thorrgh a tol.rLtorlal<br />
sp6cL€e, g. !3-!-stE !g<br />
can b6 mado to bccoo! a cunmunal<br />
nos!!! aimLng at a logtricted aaaa of mov€nr€nt. Thig<br />
can bc doae throqqh Euitable hsbltat msnipul.ation<br />
practicc bqgsd on.o implovcd knouLodgc of tho gp.cls8'<br />
lntra- epecif ic b.ha./iour.<br />
A? PRES€NI 9TUDY<br />
-<br />
Thc pllsont stuqy uas envlsagcd to dra',! quanti,tatlv!<br />
dqta llom a populdtlon of Eix adult nugg6rs malntainod<br />
undcr €iriulatad natural condiilons !t Ramatlrtha, and<br />
highlight th6 epocicar te!rltorlal partitionlng of<br />
habltat rasourcoE' nancly ul!t€!, bdski,€ 3i.to and nsstlng<br />
sitt. 0aesd on tho rcsulis rEcottl6snd.rliong hdv! boon<br />
I'ul" l,d,r<br />
nad. to rooucc itaa-clocodllo tonfllct ln uhe!' d<br />
r<br />
complots ban cannot bo mada to huoan actlvltlttg-<br />
95
96<br />
3. G L|.IiSARI (F TEItIOI|IOLGY<br />
Coo&uoal oeEti,no. Nssting by lore than tug ouggels Ln I<br />
sdlall arC! of a Lolgsr habltat.<br />
Contsct Factor. (S.qtt.on E.5i Trb16, 5 and 4) Nunescls<br />
sugg€stIng prltolrnc€ o! eqrpatlbllity b.tsr.n too<br />
!u996!r. lt !.! d.slv.d troo the root (F,4, ot th€<br />
psoduct ot lttgbtlngr ::.cordrd tqr .ach Duggsr at<br />
on€ o! eolr (n) locctlonr.<br />
Hl$archlal ord.r . ThE ordrr o? aoclal doolnancy aoofE<br />
ruggrrr llvlng ln o group.<br />
lhn-CrocsdLh conlllct. Slttattonr uhera Sctlve o! passtva<br />
con?Itct batr.an Lqn end srocodlle Eay b. ee6n ovra<br />
tha usa of cn ar€l rogardad by gach of theo qs a<br />
t9EorJtgt bagc fo! th6i! ouB usE. Fq:i sxstrplo, nestlng<br />
and balklng !lto! ot clocodth vs. c.oplng slt.s of<br />
ll,shlrmn, Fo6dlng :onsr ot ouggrr vs. flEhlrq<br />
rctlvltht by propl..<br />
lluisance crqcodLlE, CraeodllBs orhich comr near hum6n habl,_<br />
tatlon atrd causa uolrtre and anl!,dy to loeal<br />
iahab ltante.<br />
R.sourE6 paltltlonim. Dlrtlnctlva zona! qt use of the<br />
lrsourcr!, 1lkr ba8klt€ cltrl n;siing litE ahd llat.t<br />
surfac. rtc. ln a !,atger hqbltet occlpi.d by Dora<br />
than ona cuggaa.<br />
Slto fidllltv. Echaviour eqggeetLt€ a ougget's attcchoEnt to<br />
c pertlcular place by ltr s€gulallty in p!3e.ncs at or<br />
rrtlrn to thc cqor loc.tlon ln a habltrt.<br />
ElLtlggf-4Slqg.F l{ht ! b.ta.6n ouggrrr for po$rcclon and<br />
uaa o? seloutctt ln a hsbitst.<br />
Tllal nastlno. The proc€ls of dt991nq oest holre elthout<br />
.ctually l.y tng rggE.
:lt':r',:<br />
fi:is s;udy ras c daried gut at the jiugijef llesea't:b ao.l<br />
c oo.sei-va ti @. I,'uitr Ragatlrtha ( 35o5;r9, 21035tll 4prrox.).<br />
'iire<br />
p:ai: e :3 j.4 eas :.::1 :::,i;a 1-a tvlle s i;a re of Cri ssa, ( lis^. t<br />
n-:d :; llre place e)
98<br />
"""'n' o9<br />
?FG<br />
a<br />
l!<br />
E<br />
o<br />
Il<br />
MUGGER RESEARCH /i CONSERVATION<br />
. UNIT, RAMATIRTHA<br />
{.o<br />
CtT<br />
!H<br />
Ow<br />
fin *p<br />
rT-]<br />
R a ver<br />
BF-<br />
.t.- s.<br />
( lr<br />
7:<br />
tr;.FT"<br />
E5<br />
Flg. 2. Dhglanstlc lalr-out ol varlout f.cl,l,l,tlee at<br />
RaratlrthE. Bpr gs€edlrE p.n ul,th thaae<br />
pools (ArBrA). Dr Stud.ntc. Dornltory. Fl<br />
F.€d pr.pantlen. Ht H.ich.ry. Hpt H.tchlln0<br />
P.n. lr Intlrpsrtlt tovltblary (proposed).<br />
Lt Laboistoty (developtr€r. r florth. Or<br />
altflc..<br />
pl puqp tor dtaqlng s.ter.<br />
Rr Rarl,danc.!. St Stosaq. Tr Ucshlng Taok.<br />
!r Ulatet Ras.rvott Tan(. Solld ll,nes; road.<br />
Dotted llnor ?rnce. 1r TsDllnadu. 2rRaacttrtha.<br />
-F
5.I. BRE€OIM<br />
EIICL(EURE<br />
TATERIALS AI{D tlEr HOD6<br />
It lt fn opro-roo? i.rCtotutar boundad<br />
rl,l .tound<br />
by .n 1.5|l hlgh cro.otrC brick uall. Thc perlphcral<br />
lrngth auar to l8?r. Tho tot l rr a, th! prn t3<br />
2?84 sq.[. sith r lat.r-heldlrq .(lrlaq! cf s.xttur<br />
1810 rg.!. l][t.r i. held Ln thrt. {nt.scoonocicd pool!<br />
s? dllfcsant rhrpl 1n6 sLz! (F.ig.2 ). Th6 qapeotty o,<br />
th.r. poolr rr!, pool-ll g251000 lttrrop peol-Br 23J,000<br />
llt!r3, .nd pool-Cr llggr0o0 liis6r, etandtng .t . trrtrqr<br />
dcpth ol 1.25o.<br />
Fraah Bitlr lr pucpad tnto a lerltvolt, taok lro!<br />
th. !lv.s Nhalal tloulng on th. north €t th. br..dtrB<br />
rnclolurl rlsnE I raatarl,y dlractten. Fso! tha t nk<br />
gt.vtty llct o? !.t.r la [lntrin.d upt. th. bsr.dfuE<br />
pools tbsough 75r! g.lvrnlt.d pip.r rtth chlsl vrlv...<br />
oparrtlrE kryr asa allq providad to rrgul.t! ftor o? ratar<br />
tRo! poolt 6 fnd C to pool-A, rh.ta a v.rtlcrl lron grta<br />
opaSatrt on ccsEo-kcyr to lced getcr ft'or thc,ool, to<br />
outsld!.<br />
Tha tsolt .rr rcaub-elrtnad rnd rafltbC onq. cvlry<br />
lortntgbt durlng .utD.a rnd rlnt.r, .nd av.sy Eonth dustng<br />
th. arl,nr. Osrl,ng F.baualy aod llrlch th! poqls asr not<br />
illan.d rlth rn tntlntl,on to rtnLoi'r di.tusbancr to tha<br />
?arrl.! th€D th.y E!. sclrctlnq r olBtlng aLt. or a!!<br />
qctu. 1l,y laylng cag r.<br />
99
100<br />
Tha lnqleaur. (.p!n) lr rdrqurt.ly pbntld to off.s<br />
r.vatrl rpota of rhrd! rq!,d ltr.tchrr for dlrrci aunrhlna.<br />
Thr pl.nt. lnsludc rplcl.s llk! &gE, Az.dLracta, Ca€u.!ln..<br />
srntatuo albua' Adh.todd vrslc.. mrre. orradl6iacs, .nd<br />
gs rgPs.<br />
5.2. ST UDY ANT0ALS<br />
Thr rtudy grsut at anlo.Ir conslstld of slx adult<br />
rugg.rsr loua tcDrba rod tut n l.a, .ll rrlth p.aentrgc<br />
tro! th. rtrt! ot T.rllnadu ln rcothrrn Indh (f19. | ).<br />
Th.!. h.d h.tshld durlng 1978 .nd first brld ln captlvlty<br />
at R.nrtlrth. tn t9Aa. Thoir body l.r€th Ln Fcbrtlary<br />
1988 rara b.tlcrn 2.1o and 5.06r .ppaorllnatoly.<br />
Thlsa tlx |!u99.!s orrr th! asoaindar of a l.rgra<br />
group rhlch cr blosght lol r.stocklng ln natur! ln thr<br />
5irtl!,p.I llga! Rctalva. Th. ld.ntltlcatloo Earkt uott<br />
cllpptnqr on th! trll !q!t. (F19.3 ). 0n th! l.ft .ld!<br />
of th6 doubla ohotl ot tha t.ll th6 scut!8, count.d flor<br />
thr rcar toeards flont' |,o!! cllpped rt thr nuablr3 8th<br />
(raala no. 0ls), 'lrt.nd8th (o.1. no. [18)' lst.nd 2nd<br />
(frorlc no. J2r. 1.t rnd 4th (l!arl. no. f4)1 lst and 6th<br />
(fcorlc no. f5)'.td 13t rnd 9th (frqrl. no. F9).<br />
5 .3. DATA SHEET<br />
E.ch d.tr rh.at !^3 llrtrt lor I data. It<br />
halv.., ooc tc llll up ln thc dolnltE and th.<br />
thr .ft.rnoon. Eaqh hall cgnt.io6d 6 dlagrsn<br />
b!a.dlng .nclo!qr! d.plctlng thr pool!r thrit<br />
h.d tlro<br />
oth.r ln<br />
ot thc<br />
L nt!r co nna-
qtionr, tha sloPc. etd thc b6skttE ar!a., cll' '.t ulthln<br />
a osrksd bound.nr (Fig.2 ).<br />
Thr lnlotootlon uhlch u.r. tlllsd ln tqr t'ch<br />
101<br />
oba.rv.tlon r.tst (.) th. dat.r (b) th. '!.sth.r' (c) tha<br />
tlB. lhrn ob.!!vatlon ra! r.cord.dr (d) thr rt0bllnt<br />
t.!p6!.t!!c ln shad!, .nd (.) th! d€pth of tlatsr In tho<br />
pool uhlch th. .nl..I3 noraally u.td' 1..;' thc pool-A<br />
durlnq Fcblurry 1988 to DrcaEblr 1998' rnd pool-C tlll<br />
*"<br />
th. lnd of th. rtudv ' 1...' J!n. 1990' un:t"'l<br />
f:<br />
lr. av -;ll. ttss {han 3oa- t,ata' bera'r< 'l Ftoaa't'o.
02<br />
F<br />
s<br />
F<br />
I<br />
g<br />
F<br />
F<br />
)<br />
l.<br />
T o<br />
lt<br />
F.<br />
o<br />
l(<br />
o<br />
$<br />
5<br />
I<br />
(<br />
o<br />
I<br />
a<br />
3<br />
g<br />
o!<br />
>t<br />
Jf<br />
|{o<br />
!0t<br />
EC<br />
q.,<br />
+c<br />
o<br />
:a tt<br />
Orl<br />
or<<br />
tl<br />
g1
It u.. posribh to ldontlfy . olggca tn uctrr It<br />
103<br />
li r.r t9, lhlcb h.d a dlrt1n€lry l,lght.r body col,our, o!<br />
uhcn Fg !ra rlth anotblr nuggli ln uttc! uhilr fout otn!!!<br />
toralnrd out.ldc.<br />
Date in tho oornlt€ $G!a colllctld aftcr 90 oLnurra<br />
of rqnaie! duli.ng th. uint!! and ralna, and Juat aroqoo<br />
tunrlac durlng ruonra. Aft.rnoon d.t. uctc collactrd<br />
$ound runlrt duriq ell t!saon!. Thr tlal(E! e!r! ?ixtd<br />
to coatoar clth th! ttla rhln rt lc.st tour Duggllr rrrc<br />
oltald. fatas. Thr t,lrlnlt u.!r not changrd durlng rny<br />
prttlcular r!rk. Shl,ttr urrr ulry gr.du.l to rccorodat!<br />
tlllngt of runsLla tnd Bunrrt, 1nd uer6 usually utthLn<br />
lLlt..n Ilnqtra bstu.ln .ny tuo usgkly 3h1tts.<br />
'.5. DATA IIItrERPRETAT IOI{.<br />
Fldolitv to stt.sr Data on s&htlngs u.sr t.bultrd<br />
to rhor (r) tha tot.J, nunb.rr ol oblarvrilon. takln<br />
dutirq tht nonth, and (b) thr p.rcantrgc of l,netancar<br />
thon th! .u99€rt srr! rightad outtlda ortrr duttrB .rch<br />
crlandsa .oqth (Tabla 1,). Th.[ datr rarc lntlrDrltrd ro<br />
rhsr fld.llty to rt.r by Lndlvtdu.L rugg.ls ol both<br />
r!x|' (T!bl! l) ard I g!n!r.I lldcllty to uat.r durtng<br />
thrca rrln goqaona. !l.nt!r, ruoorr rnd rtln (Trbt! 2)<br />
(f!9. 4). Th. dqlatlonr of th! r.saona r€r!, ov..bra to<br />
Fablualy, 0hrch tc Jun., rnd July to octob.r, lrrp.ctlvlly.<br />
For cosrlbtl,on ot tha rlghtlng dai. to lnvironaantt!.<br />
p.Frot.t3. thc drpth ol lstrr in thr pool, th! ..bl.ot<br />
tarpaa.tu!! .nd srlntrll rero rlso lrcordad (T.bI. 2).
104<br />
TnB LE-l . Crocldvluo cslusrtrjl: at. RdD.ttrthrr monthl,y<br />
lncldlnc.. ot llghtr,q { (S) out ol totql<br />
nuEbrrr ol obroavrtion! takrn (0). F?. F4,<br />
F6.-F9, A8 .d ott I .r. th. ld.oliticatloo<br />
nuoblrs ol .dult s!gg.r. houeod Ln thr<br />
brc.dlng psn (r!r t.xt at s6ctl.n_5.2).<br />
Y.rr Obrclv.tkn - Slghtlnq I (S) ot.to;a{,.u-te,<br />
Eonth<br />
nuDb€E. (O)<br />
F2 F4 F6 F9 l||8 fln8<br />
| 988<br />
Frb.<br />
lrt.<br />
Apa.<br />
my<br />
Jun.<br />
Jul.<br />
lq.<br />
S.p.<br />
tlct.<br />
lov.<br />
O!c.<br />
1989<br />
Jrnr<br />
F.b.<br />
fa r.<br />
A pr.<br />
ly<br />
Jun.<br />
fuI.<br />
4?<br />
54<br />
59<br />
62<br />
58<br />
58<br />
51<br />
57<br />
52<br />
48<br />
4?<br />
4l<br />
100 94 96 89 95 98<br />
82 80 78 A2 72 ?S<br />
83 99 90 97 84 98<br />
85 9? 95 92 9? 90<br />
50 80 83 E9 69 50<br />
2? ?1 86 92 55 45<br />
5E 95 92 90 51 60<br />
40 8.t 90 90 48 53<br />
59 81 ?9 75 70 72<br />
96 96 88 .96 94 92<br />
4? 88 79 72 58 74<br />
95 95 93 85 95 91<br />
87 94 90 88 88 90<br />
?0 68 80 71 80 54<br />
50 62. 6s 65 69 50<br />
38 46 21 29 63 23<br />
30 15 34 40 2A 50<br />
21 ?E 51 80 41 54<br />
contloucd..
TA BLE-I . oonttn{tcd<br />
Ylra 0b36!vatlon slghtlttg ,( (s)<br />
414.<br />
Sop.<br />
Oct.<br />
ll.uo<br />
Oa€.<br />
19!X)<br />
Ia.<br />
fd.<br />
!aa r<br />
Al8.<br />
r.y<br />
Jun.<br />
isit'i't<br />
Staodasc<br />
Drvi.tlong<br />
51<br />
so<br />
57<br />
53<br />
57<br />
JO<br />
50<br />
60<br />
5?<br />
5a<br />
55<br />
s4.F<br />
4.9<br />
1220202088<br />
10 40 26 28 10 30<br />
39 09 40 {0 42 40<br />
89 gr ?9 74 ?5 81<br />
88958p 869691<br />
97 9€ 95 100 97 66<br />
92 90 96 94 96 88<br />
?5 ?8 8? 73 77 ?3<br />
r7 a9 37 ?2 45 35<br />
39 32 15 ?0 4g 32<br />
17 68 51 74 53 34<br />
2g 22 25 ?6<br />
105<br />
61 7S 71 74 66 62<br />
26
106<br />
1A$LE-2. Crocodvlur qalust!ir j! n.l:ratlrthd;<br />
ljJIM ER<br />
so!ron.I lnqldcnqes of sighting (f)<br />
Jo:tpoct io totrc6ponding atublont tsop.ratur!<br />
(f-C), tot!1, rElnfa11 (ttcn) and !,3ta! lovol<br />
(UJcl{)<br />
Ln th! pool ln s8c.<br />
. I ro.<br />
Sightingll;---1;-l-!r'---,----) | | t<br />
I I<br />
- - --- --: -i seslr!9-:l!V9!r!9 -- | I Rurn9---_g_99__<br />
mran sqllmrsn SDrimron Sqlnc,al oqyglmrrn SO+<br />
_ -_ --_ _ r _ - _:_ __ _ _ r_ _ _ -_ ___:_<br />
'lEt y!.r 96 4 23 2 26 2 - - 35 2<br />
2nd yeat 87 1,2 13 2 21. Z i.s S 94 48<br />
3rd ysar 90 ,l 14 2 20 3 8.9 6 12s 0<br />
Ifeao 91 5 17 6 22 S 3.? 6 85 46<br />
+3.1 31<br />
EUSEE<br />
i8t y.ar gu 20 ZS g go 4 66.u 24 gg I<br />
2nd yocr 51. 19 22 4 29 6 7s.6 32<br />
'125<br />
3rd ylar 55 18 22 3 27 4 62.A 54 125 0<br />
mqaR 52 16 23 2 29 2 65.5 37 96 50<br />
J3<br />
3.9 16<br />
RAIN<br />
llt y.ar 69 20<br />
znd y.8r 34 20<br />
!ll6.n 52 25<br />
Oata for<br />
5ianda!d<br />
dlff.r!nt<br />
23<br />
23<br />
u,tnte!-1 st year onfy<br />
n<br />
2 67 .2 7U<br />
3 91<br />
.1 60<br />
u 79.1 55<br />
16.9 -7<br />
Davl,ation (SO) val,uao aro frcs the ooan ot<br />
ob eo r\,ratlon y rara.<br />
of FE b ruary.<br />
0<br />
54 19
o<br />
o<br />
o<br />
s<br />
month<br />
Evenin(r<br />
I<br />
orning<br />
Fig. 4. Trend of ej.ghtlnq of osggErs oltsido urato!<br />
107<br />
duElrq diffolent month6 at Ramatirtha. 214 e'tc.<br />
qorre6pond to cal€ndar nontbs Feb, tp!11 etc.<br />
Rr 5 lnd U, ar,6 ths €oaaooa of !sl.n, suDna!<br />
6riid urLnt!r, !s6prctl.ve!.y.
Fldrlttv to b"kino sitst 0n s€palats dilgrams o?<br />
thr brccdl,ng snclogursr ?or rach ougq!! thc aightlngs srrc<br />
Dlottod rc solld dotr (flgo. 5 to 10). conq€ltl'sn! ol<br />
dota .t pastisui.l placs3 hav! blan conEldcl6d as tha sLtr!<br />
o! polt1oBc of ths lncloasr! oo.t prafera.d by a ouggr!.<br />
{.^rther<br />
In rrl.tlon to thi! , .nalysl. eaa c.rti€d gut E3 st8trd<br />
balor undrr 't!rolJ8c! utillrrtion rnd t.rrltoriallty' .<br />
cooortl,bllltv rnd dorinrQE-tl Tha laqucnc. ct proclduta<br />
follorld te .tudy thts! asprct. of quggrt brhrvloua ralr<br />
rr ?ollo!!.<br />
(r) Thc dtrgrrr of thq .nclocur! !|ae dlvldld lnt.<br />
E.ctlono o? 2cr x zclr $Pra3.otl.lg tn ar!. ot applox,.lrtaly<br />
8. x 8i !.eh. All elghtlaga t.krn tog.thtr ?or tll Eogg!!"<br />
on th! notthran hrlt ol thr p.tt tto .t€'e uelc l'6ntlllrd<br />
rhasa .oat soncanttotlon! o? llghtlng-dots occurrrd.<br />
strll3llyr on tht |outhatn hrlt tno othra 'r..! !ca'<br />
..rt.d (ftg. f1). fndlvld$l rugg.ar uhlch rlorln'd<br />
togothar or ahrrrd thrac foqr idontlfild:oorr<br />
lrdic.tld<br />
thcl.r eorp.tlblllly ln t.ltc of .tflnlty or tol.!.ncr.<br />
(b) In osd.s to .lcartatn r dogla! ol lrhtlv!<br />
coeP.ttblllty lnd tha lav.ls ot doolranqr, thc !3u d.t.<br />
fro. th. dat! lhrlts t6!t tabulatsd io gcnrlatc n!t!.!ical<br />
vrluccr lrtlrd hala rr 'sontact factolt' (CF).<br />
(t) fn Trblo 3 th! nun.rals sho!' out of its<br />
totrl nulbcss ot alEhtingr, thr porc6otagr of inatanca!<br />
ohln a rugg.! 3a! slghlld l,n 6.ch o? tha idsntifi'd ?ou.<br />
praf€rrEd ton.ar n.DcJ'y<br />
r noaths6st (Nu), northtatt ( E)'<br />
southrcet (su)' rnd southorrt (sE) (Flg' 11)'
In ordls to handla tha aoor our rat dats nor!<br />
ct?nctlvaly, I ololEstr pcrclnlrg! ol oightlng ot 15t ln<br />
iho oorth pool rnd 25F ln thr !o!th pool lrcs conaldol.d<br />
.s thc |rinl,our noar'to tpqeat lo th. Tabl,. 3. Th.<br />
109<br />
dlfferartGc la th! linilur noDE foi ths tgo halvos of thr<br />
( rs7.)<br />
prn lFa lo vl.u of th. fact th.t tor d gr.at.r p.rtret tha<br />
obsrtvstl.n prslod ( ovsdbor, l96s - Jun., '1<br />
990) th.<br />
.quih pool cootaln.d 9!dt6s drpth of ratcr than thc north<br />
tocl (pool-A), .nd oogt .lghttngr r.a. recold.d 1n th.<br />
gouthr rround PqoI-C.<br />
(lt) Frrr T.bl.-s c.nt.ct factor. ('CF') for<br />
rach rsggar llth othar rlggltr tn thr pcn u.r! drt.rdln.d<br />
ln tba lallcli]€ !.nnar. In 2q6j-119 (frblc-3) !8<br />
racesd3 18.01 vrlu. rt th! lncldcnc. of a19httn9. In thr<br />
a.ra :ana F4 iacord! 22.3f. Tha CF val!. tos !8-F4 oas<br />
d!t.t!tn.d .t thc y of thetr prodaet , i.e. ) zo .o (Tabl.-4 ) .<br />
Stolhrly, ll 8 hsd qontrctr rith F4 1r| th! zon.llE<br />
(20.8tr rnd 22.3F) qnd SE (44.9f rnd 2?.oF). m,rLtfdjeA adlf<br />
logcth.s, th. CF valu. for ol8-lA r'as Z'l'5 (Tab1c-4).<br />
Sush CF vrluts to! rll Parslbh cont.ct! rmong rll st'r<br />
Euggtrr ara Prasantad tn trbla- . Thra. d.ts hava bcan<br />
ur.d to drsonrt!.ta tha Isvtls of Ptltc!anq!-coe9rtlblllty-<br />
dqolnancr rtc. ol Drlla rlth dltfcrcnt frmlcre lnd th!<br />
tEr 1619. trBl.t ulth otbrr t!. ?rsalre (R!' 11)'
110<br />
Rcrourc. utll,iattlon rnd trr!1toplal1tv, R6eourcc<br />
utilLgctlon h.v! ba.n dlacu€rad urd!r tho r.p.dt.a of (r)<br />
us. of lh. anlnsls st oth.a r.x lo! .rproductlon, (b)<br />
ugs of th. p!!lrr!€d ncctia€ r1trs, rnd (c) usq ot thq<br />
prcfrrlqd bteking cltcr.<br />
(a) Data on contact factora (rCF') froo Tabl,! 4<br />
r,€!c urad ta shos th. rltln1tl,a. rnd/or tolqrancc fsvols<br />
brtos.n mrl.r rad IrD.Ica, tnd fs611!r and fcnelor.<br />
ThlEr LnforlEtion havs alao d6songtratld the hlrs.rchy<br />
!f dooincnc! .cong any tle rlsr rnd lou! fcoalar.<br />
(b) 0n e di.gt.r o? thc blosding prn (Flg. 11J th!<br />
nrrting rpota fos rrch flcrf. qt. plcttld for rIl tho<br />
thrm brecdit€ a!a8ona. Thr drtra of ns€tir€ u.!! a.tch.d<br />
te n.atlng opots (Tqbb-5) te trcutqin It th.rr u6rr .ny<br />
plr?lrancr ?.! c p.rtlcuhs nc8tirE spot .nd l,l thrrr<br />
urtr any rlgnr of htla.tshlrl aaqulnc! ol ulc of th€<br />
nratlng !pot9.<br />
Thc dulst1on-grp b6tur€sn flret rtrlal ncatingl<br />
and tho datr ol fl.rst ncstlng oerr aecertalndd iten tho<br />
d.ts shr€t.. This Lndlcctcd ths tina eince lhon actlv!<br />
dcf!ne. fo! utlll|rtlsa ol thr hrblt.t lEaourct !,lth<br />
lesp.ct to n€rtj.ng Eltr l.y bt ttartlng. rTrlel nrat.'<br />
sr! !hr!lcE 9lts dug qut at potsntlal, n$EtlDi slt6!<br />
on ecvotll nlghta et .ov.!tl tpott, b.fs!. actual<br />
ncatlqlr Thls bohavloua 1r b.lirv.td to bo rrlat6d to<br />
rctive Eof,€ctlon of r a€atlrq sitc and/o! . procoss<br />
shich 8t1tulat.r physiologlsal ploc€sscs cuLmlnatLng rn<br />
rctu.f nestl,B (Slngh, 1990rp401<br />
).
Tsbulrt€d d.ta on sighting incldencos v!lt<br />
al,so .rnalyard to flnd out ll tha.; lr€ft any patttt.l<br />
bugg€etlnq fldsllly te tho ns.t durLng tho .ntltd Po{l'rd<br />
of rgg l nqlbrt 1on.<br />
(c) froo Flg.l'l .nd T.bI!-3 d.ta !.rr 1nt.!Fr6t.d<br />
111<br />
to ehoE ths otdc! of incidlnc€ ot eightlrE (f) 1'] thc fout<br />
lon6r' illil<br />
r ;{8, 5Ur Bnd 58. luhsn r Paltlcular ron6 e!l<br />
u6ad by oor! than ona anLEal o? thr sang ..x, tha ordal<br />
ot llghting lncldrncr (!) rrl rrorlncd to rsc.ttrln thr<br />
blorarchy ol ua. ol tha basllng ri.tE. flgurs! 5 to 10<br />
sgte o.tsh.d to dstcrain€ lf th6!. sars total ovcrlaps ol<br />
sole dog!.!s ot Paitltlgoing of btrsklng eitoa aooog th.<br />
ouggrls of, the saoe g3x using th. sans zonE o? p!€fgtlnct.
TAgLL-5. Crocodvlu! palu5trlB 1n br6€ding pdn rt<br />
Raratirthc: 519htl,,i! lncldcncoe (f) ln<br />
dltfellnt zonla rbevr th! norE of 15)(<br />
(ltut, llE) and 25F (5rl,r sE). N, s, E, and u<br />
rlr notth, routh, €act, lnd 0rGst, r€gp.ctivaly.<br />
S.ctionst<br />
0ugg!8<br />
tir! ItE<br />
ShJ<br />
T qt.l,<br />
!6<br />
rmI<br />
72<br />
F4<br />
F6<br />
f9<br />
- 18.0 49.4 6? .4<br />
15.5<br />
20.6<br />
22.3<br />
17,1<br />
17.1<br />
35.?<br />
44.9<br />
25 .9<br />
27 ,O<br />
41 .5<br />
31 .0<br />
65 .7<br />
7e.l<br />
4 9.5<br />
5 8.5<br />
4 8.1
t"<br />
d><br />
,t<br />
Fi9. 5. Psttern of slEhting<br />
dullng Feb.l 988 to<br />
of rlugB<br />
6rr mg<br />
June 1 990.<br />
113
t4<br />
t:<br />
Mra<br />
tlg. 5. Pattsln s? slghtfiq ol EUg96r, fil I<br />
durl,rE F!b. 1988 to Juno 1990.
Fls. 7. PEttean ot sl,ghtlrE of s(€get, F2<br />
durlDg F3b. 1989 to June 1990.
1. ,)<br />
i<br />
Ftg. 8. Pattaro ot llghtlng ot .rEgor, F4<br />
durlng frb. ! 988 to 5un! 1990.
fig.9. Pett€rn ot<br />
durtr€ Fob.<br />
s19bti9 of qsgg.r, f5<br />
1 988 to Jonc 199i1.<br />
tt7
J/.. . f' .xtr-<br />
'.1.'<br />
: i-'{r<br />
F19. 1.0. Prttlln o?<br />
durltg F.b.<br />
stght ing o? [uggsr, f9<br />
1 988 qnd Jun. 1990.
--:<br />
.tf<br />
I<br />
Ftg. 11. Prgterrsd zonoe o? baaklnl (Nllrnorth-tlBsti<br />
\.-<br />
\<br />
119<br />
NE r north-aqst t SOtsoqth-d,sstl SElsouth-6ast)<br />
'rlth abovs 15F of total slqhtirE and psefErr€d<br />
zonos ot no!tt.€ (f 6tnal9 idsnttfication nunrberg<br />
2,4'6'9 olth eupgr6criptlona ol ysars ot<br />
ntrttngt rr1 986t b!1 9891 cr1 990)' mtmal!i<br />
F r f ana16.<br />
.l<br />
I<br />
I
tI8<br />
T;6Lg-4. :aocodvlr;J r,rlustrls dt Rdnatlrthdr<br />
fl I 19.8<br />
f2 42. s<br />
F{ 20.0<br />
F6 1?.5<br />
F9 17.5<br />
suc fot<br />
all<br />
lalgg -<br />
Coetact Fectors (GF) brecern dLllEfrnt<br />
ruggorr Ln tho brsadtn? lrn.<br />
88 tft I F2 14<br />
Sur for<br />
alI<br />
?aBIr!<br />
9?.5 115.a<br />
19.8 42.5 20.rJ 17.5 1?.5<br />
- 34.1 27.3 2s.5 26<br />
"5<br />
It4.1 - 26,4 32.7 28.3<br />
27.t 6,1 - 55.{ 2S.9<br />
25.5 32.7 53.4 - 3s.8<br />
26 .5 28.3 28.9 35.8 -<br />
- 75,6 47.3 45.0 44.0<br />
Sq|| lor sull foa<br />
t5 F9 all iaLoe al,I f€Dal.r<br />
{7.3<br />
45.0<br />
44.0<br />
9?.5<br />
't't6.4<br />
tloter m6, Elg, f2t f4, F6 and F9 qf€ ldofittflcatl,on nunb.r!<br />
tot leb and fo[Eb ouggar!.<br />
Contaet Factoa (CF) bctreen anlDsl rA. .nd anlnal rg.<br />
.<br />
u,h6ra, 1' 2r... n !!r c!!aa tn the studlod hablt6t,<br />
PA cnd Pg ara, tarp.ctlvely, the f ol tl,E6s<br />
(tror Tsbh-5) rhon cni!.t A rnd B occupl.d<br />
lo 6r.q oqt ol tba total nlobess of ti.6s<br />
..cb lat ctghtod ln th. habLtat.
9,<br />
pglCg_tl_i : Contact Factor<br />
FIg. 12. contact Factots (vs!tlcal coluon)<br />
oal€ (It18, fi'| 8) and fe&ele (F2r F4'<br />
rnd correapondlng nr.rnerals Jt the<br />
the bars) asEgrrg Et Rssatlrthq.<br />
o o1t eil en<br />
F6, F9<br />
top of<br />
12l
t22<br />
TABLE-s. lroccdvlus palusttls rn the broeding pen at<br />
Raoacirtha: Ths soqu€nc€s of nesti,ng and otd6r<br />
of use of th€ nas."Lng si.tss durlr€ Lh!se<br />
o6.ting s6aaons. Th6 numbsra (?r4r6,9) ghouJ<br />
th6 identlflcation number of ?emalss, and th€<br />
lstt6re (NulrIerSu,rSE)<br />
shou ths zon.s of th€<br />
bac!ding ps n.<br />
S€qucnc. gf<br />
n€sting.<br />
l 988 1989 1 990<br />
222,9<br />
5 6 6,4<br />
94<br />
49<br />
Ordrr of use NUJ Nll, NUI,/SE<br />
(2) / (s)<br />
of th6<br />
NIJ NU' NII]/SE<br />
nastlng sita (4 )/ (6 )<br />
NE SE<br />
Nll, ilui
6. L 5<br />
AmcrE rlL al,x ruggrrr thc dlcr!.glng lrd.r o? lnctcdhcr of<br />
.19htlng C{) outsid! r.t!r llrol F4-F9-F6-m6-[nB-F2, urhr.cr|<br />
a tha lnclcasing oldar of tncldanca o? kr.plng to qratr!<br />
.t th6 tIE. o? rrcord (r.an valucar Trblo-1 ). Ih both<br />
OT(LA<br />
i!x.a thc ardlr ^ ?fsr! th! an ll, anleal to th! larq.<br />
rnloal.<br />
Sighting outald. !.tcr tr.. olnlruo durlng th. rltlny<br />
3..!6a rna qaxinut duslng thr ilntrr (Tsbl.-2). Th.<br />
oaxllur right,lng ostsldc !,at.s .]ro colncldad t'nr<br />
ts.rsn rh.n th. tllprr€tulra .nd thr B!.obo, s of roiny drrr<br />
5.t. th. lcurtt (Trble-2).<br />
Ai,l r!€galr htC novld ovar th. cntlrr br.rdlng pcn<br />
(.lghtltr0 dotr ln tlgr. 5 to 10). Th. t.vourlt. lpotr<br />
of b.rkirq !htl! qutrld! r.t6r or tuttssln8 ln shallos<br />
uat.! !r8r. avld.ot ttoo th! congr.g6tl.on of dotr tor .tcn<br />
I ni&a1 .<br />
sighting. el F? ucr! tho r.rt ln th6 zoncE llll,<br />
rori SE (Fig. 1l). In SE th. rp.s. !.. .l,ao sharrd ui,th<br />
tr8. zon.-E r.. rh.rrd by both 61,.! and th. r.t!6LnltE<br />
that! ?.oal!r. Sll, zon! rt! lhalcd by I[l I rnd rll fcnalrg.<br />
F2, thclofosc, h.d dorc ouabara oli prlflrlcd aloae of baakl3E<br />
th.n oth.r.ugqcr! (Flg. 111 TebLe-3). Cong!!qrtlons sf<br />
.lghtltE dot8 d F4 .nd f9 clola to s!.as 6f F2 .nd F5<br />
augg.rt.d talcraflcr by both th!sr latt.r f!oa1!c nhl,ch arc<br />
largrr (Figr. ? to t0).
Thr hlghar to looll ordar ot hirr.lc,hy of use ot th.<br />
.onrr by dltflrrnt lcrnalcl rrc ss folloos (TabLc-3)r<br />
Zonr-N!/l t2<br />
zonr- rrlEt F1-(f6/ti)<br />
Zonr-sEr F?<br />
Zo nc-srrt F5-F9-F4 -F2<br />
No lnala<br />
fln 8-rB<br />
UJhtn r paltlcular :on! rar lccupl|d by oorr than<br />
.nc ouggsr (f&.lt) thr lndtvldurl .sgg.r! dtd B.tntrln<br />
r.ps!.t. rr a rithln thr zonr (FIg.5 te l0) ruggcrtlng<br />
prttltl.nlng af r.!turc! to! barklng.<br />
Thr contsct f!cto!8 (CF) (Tab1.-4) st nB ||lth ?!aaIr.<br />
urr q7.5 , uhtl. th.t .f ll18 sr. t16.4 Durlng th! brrcdl.ng<br />
aarran! lt hra baan obarrvrd thrt f2 bccen.r nott rggrrrrlyr<br />
lnd plrvcnt! s.ntrctr o? rth.! ?rErlrr tlth |||8.<br />
recassive<br />
Thr gt vslu.! rl rlllfrnrlrr rlth n.L.a !.r. rlt.lt<br />
thr faotr rlthin . sarEc of 4r..0'47.3 Evrn though F2 uai<br />
t.larant to F{.nd f9 tha CF vrlua .t th. tuo r.c..!lv.<br />
.t6rclre rith F6 u,sra ga!.t!r than ulth F2 (Fit- la).<br />
Thc d.trr lhcn tlrlt tllaI nBrtlngE urslt obqorv.d ln<br />
th. y!ra! 1988r 'l 989 rn1 1990 t!!rr th! 25th Ftbruary' 17th<br />
{bash, .n4 10th f.brural. Th. c.r8.lpandlag dat!. cl<br />
llrat a!.ttng rt th! sa.rons |tcra th! 17tb. ttarch' 18th o.!cb,<br />
.nd lst}l mrrqh. Thlref.rrr, tlrrt n.ltlng osqqr!.d 20 to<br />
!18<br />
tt'l I<br />
25 dryr bltor. rctttt ncltlag tn 19Ba rnd 1990.
lrra-l[, Loc.ludcd thr tavoullt! rr!.s tor n.rtl]€<br />
(F19r. ? to 1t) (Trb]o-5). Tho dccirnot foFaIr FZ urto th.<br />
tito flrst dlrLr€ .II thr... o.stLr€ eq.sonc. llc tlrs f.nrl..<br />
oalt€d. ln th. 5a|' rone 1n ih. s.o. .l&ht. Ov.r thc. y..r.<br />
grotllng l.riollr..|ca o? t2 to F6, .nd Lt.r to F9, h.v.<br />
treult.d; tn. tartl,t|rl,tl ch.B.!. Thlt ls .lso avld.rlt tro!<br />
total trrvr$tl,on .f th. tue frdlca/ f5 .;od F9, tleF nostlng<br />
ln ilU. f4 brirq th! rroglllr|i oar rpparantly tolErrtld by<br />
f2 to n.rt lD trlll on r dlfflr.nt nlght In 1990.<br />
D'rtlng th. agE lncub&tton pBrLod vL8ite ta th€ n.st by<br />
..qh DtEgr! accurlld durlrq thc nlghtr ar usra lvld6nt fror<br />
rpocar !.!n 1|l th. 6ornlrE. Durlog Cry tlD! F2, F4 rod F6<br />
cliobad up tha brnk upt! th.l!, llspectivc no8ta Lf !,.<br />
.ctad ln | !|.nnar auggrrtlrg rrmcvrl of !.nd lro0r thr nrrt.<br />
Actlvr n.rt gurSdlng rt tho n.ltlng rlta {rca ccrn onLy<br />
ter f9.<br />
Ar tn lrpsllreotr, 1B tll,llt 1,998, a tuUy drcssod afflgy<br />
s.a !.d. to rtand .t th. n6tt .f t9. Th. t.!.1. idBEd1.t.ly<br />
125<br />
Lrlt itr baaking rlt! .nd c.!. clolr to thc clfigy qith oprncd<br />
Jrrrr but dldort rttrck untll th. lffigy ur8 put to rotl..n.<br />
Athck !r! rt thr IlEbr.<br />
In rotthaa lct of rxpqrlo!nt9 rrcordrd distre39 crll<br />
gl h.tchllnga ocrr playad rt rbout 2E clcy froo tho n.!t ol<br />
F9. lhlt drru rll frnal.r End llal,!s tourld! th6 lolrcr €?<br />
4u*'l<br />
thr strll brlt only F9 sllnbrd out (t,pto thc acurcr. |l,hon th.<br />
c.336tt. player- oa: ehifta{ F9 luehad upto It.
126<br />
O ISC USS ION<br />
FidaLiiy to a spot, al,60 knourn as .tsrritorisL<br />
baskir\Jr in cl:oDodi1lan6 ls recognieed as an aid to stusy<br />
and cangu9 uILC popuLtloos of ths Amsrican a11ig616",<br />
AIIiqatcr misslesippieosis (Thoopson and Gidd€n, 19?2),<br />
and the gharial, Gavialis oariqetl,cus. (Sin9h, 1905:pp 2?).<br />
B€qauas of suctl f1dcl1ty t9 pasticular spotg ev€n qn<br />
innocuous gp6cLrs likr the ghasial ooy cA.us€ qccl.dentB to<br />
hunanbrl,r€ (Bustard and Slngh, 1981<br />
).<br />
Such lldcltty t,t uat€r qnd basklng ettoo r!6 provcd<br />
rrith g:gE|y-b: palustris from tho 16sulis of th6 prgeant<br />
rtudy nt Renatlrthar In r ouggrr habltat, lven lf a<br />
clocodlLe sanctlrary 1c gazetted, it ir oftrn not poBslblc to<br />
c!6dlcato huocn actr,vltica und6r IndIan condlllon!. Thls<br />
faator, thortforo' n€6de lo bo rcAulatod ln ths Lntolset<br />
ot hu&.n 9af6ty. It utll be possibLe lf the nirnagenant<br />
4 *u'|rvi<br />
j.dantifiss such basking gpots(to"r!hich thsr€ is sBasorEl<br />
or totBl fldoLlly, snd l,npogo b3n on hurBn intruslon'<br />
As suggest.d from tha pr€scni gtudy ihe bgst knoun<br />
9€a9on for aacsltainlng tsrrltorisl 9pot3 of nuggcr i6 th€<br />
u,lntrr (TablE-2). Thts acason l3 alao th6 tio! tlhich<br />
tboodiataly pracad6g tho onglt of ths bre€dlrrJ seaEon.<br />
Thslcforrr lf 16ft undlstuabod at the tetrito!iaI bBtklng<br />
dites, and subjoct to the avallabillty of 6u1tabl€ oostlng<br />
Blt.sr th6 Eugg€fs say nat Dovt auay frofil th€56 gpot!<br />
until ths sggs hatch around nonsoon. As a nBnagement<br />
oraciica undcr habitat osnipulatlon guitable n!stlng sitrE<br />
can br prapolad at trrfltori.I<br />
baaklng eit68 ulth 'n<br />
uttloats alo to reduco nqn-cr9codlfB ccnfllct 1n naturs'
Thi$ sLudy j,ndicdtcd th.rt 0von 1l "iro fdftrl'9 inug!o.rE<br />
eupear to larrra:,n ln th6 game zoos of a habl,ta+" fine!<br />
p.rrtltlooinq u,iLh r6spoct to ths uao of r€sourcr c.rn stl.ll<br />
be th6rc. In the !rild urhs!s sBvs!al aiju-Lt fsmiiL6s occuat<br />
and th6 Enagoment dcsir.s to devsfop ne:iting aroas urith a<br />
visu to lastrict movoognt, araaa of th6 crocodi.las, lt !riLl<br />
bc nosegsaly to d€vllop such siteg lsing oppositg banks<br />
sg that taklng ov€! ot ths nr!, slles 1o accornpllshad lrith<br />
a rtolEal manife3tatlon of thei! territolia1 btlhavlout.<br />
72',7<br />
Clocodi1laflg at9 knou,n to usa tho sams elt€ of nestlnB<br />
6very ycar. Th€ lnuggor srqc9dil€g comm€nce trj.al nesti.ng<br />
qbout 20-25 daye before astual nsating. Thorefolo, ln !<br />
osggrr hatJltqt uh6ro uithqut, rosortlng to hablt.t nanlp!tl.t1on<br />
praotlcas lt<br />
o.A ' -'lt2t"ct'(<br />
is doEirld only io ld.ntlfy{<br />
rclored EEasonl<br />
to roducr oan-ctocodile-sonflictr<br />
lt Ls lscommendod to<br />
gtari the clog.d gsason a nonth bsfor! actual nssting.<br />
Th! datcs of n99t1t€ ln mugget follaus a p!og!6s9iv6<br />
gtadisnt o? risa in 5umm6! t€mP€latu!6 flom gouth€ln to<br />
northcln Indir. In Tanilnadu th! ncstlnq eodson coon6neoE<br />
around f,anusry, in ollssa ,.t l! duling mld'lltslch, and ths<br />
Hj.oalayan totEle lgsqrd Aprll as tho ndstLng sBason'<br />
Lay ing Ef tuo clutchss qf eggg P6r geaaon hav6 bs'n<br />
leportgd sincs 19?6 tor !. gll5!g!:3 at madras (ujhitakE!<br />
aod uihlt.ak63, 1989). Lanco (198?) cautionod thbL ,by<br />
sttelptlnJ to increaea ths nuob8r of clutchgs in a year<br />
th€ Lncroae6d Btre.s on ths ?rnql5 urould b€ 1lkely to<br />
lrsuft ,.n redecsd clstch slz!, Infello! q(6llty of eggs and
128<br />
ultloatlly, p!!m€rturr sencsccnc!!. Thle qont6ntlon can<br />
tt€ oxtsndcd to rlvleu gtocklng pettsrng of aduLtr 1,t a<br />
btaeding proqlamm6 on th€ basi6 of data colLocted on<br />
mal€-fana16 contact factors in thg plosgnt study.<br />
Fo! a br€sding group of foul lruggers it ls consid.red<br />
j.ncorfact tg ka6p only One dalg bEcaug€ of ths fsar that<br />
tho lons nE19 mEy hqvs goms rsploductiv€ defsct. Again,<br />
tht dat. on eontact factolg (Tabf€-4) euggest that bocauEs<br />
ol tha psesosllvonssc o? ths dqninant fomsLr r..rvcr<br />
tho l1r!t<br />
mal,e, th€ Eccqnd 0a1r eontribute8 th6 most so that ths<br />
valuca of sontlct factor or " rr lif'i"l'"" for mats! ts<br />
lcsd at 44^o to 47.5. Thst neant thrt tho egcand nalr !.n<br />
ths llsk ol pllnaturr gensscsnc!. Th!rafo!., svrn It a<br />
,ruggsr nlql,a csn taproducr urith 96ve!al farml!s, for Long-<br />
t.ro s|anagem6nt o? E, h-Ea llh1sr.-brsedlng pr-og<br />
ir<br />
ramoe 3 malesr<br />
C^r;6f i^ (!rh tD ha '&; l; 2
g. ,iC KllUlJLf DGCTTEI,ITS<br />
ilqtin,.,j thc course of ttr is study sevtJ!.r I<br />
Psopla .rnd'oa,jdriLsationg have he.Lped. Son6 of<br />
th€ss a!el<br />
':Thc 3tqt,6 covt. of Crlssa, princioal Chllf<br />
Con6.!\rato! ol Forsats (Orlssa), Chlaf uitrlllle<br />
Uardan(Orlssa), Fle1d DIrEctor,:imllipal Tlasr<br />
t29<br />
Rssolvo, Ins. Se1Ly [Jalker. (loo Lutreach Urganisdtlon,<br />
India) Jnd tils. iusan ta!nard (Zoo Atla6g3, LJ'A) fo!<br />
orqan1t3tlonal facllities and fo! l"itsratu!e relatcd<br />
to the cours€.<br />
: $r. 8.C. Cha udh ury (SlB nt Ist, ,,J1l.dtif<br />
I Instituto<br />
of IodLa) and Or. S.K.Kar(tiasearch gfficsr,d!j.ssa)<br />
fo! inf ornat lon.<br />
: filr. 1.O. Ro(Itr|i].Sc.(R€search Asst.),5!1 H.C.cIri,<br />
B,A, (C1erk); sri covlnda T<br />
S!1 Savana ttarcndi and 5rl<br />
for hrlp at varloug stago€<br />
dlscussion, analy sls and ptdsentation.<br />
Lf,A provided a lelloushlp t.o<br />
ar:-i-..rJ. o,urqg en er t<br />
c ol.Iede, Can-rj+e. ii:'.::,<br />
C;.rrse;-,rto.:.<br />
udu (f:lug ger Ke€par), a nd<br />
p.C. Goch hay at ( liugg e r Att!odarl)<br />
of cjata col.lsct ion,<br />
'. The Ccn96rvdtlon TroJtJ ,uppori. f und, ,:1-ryLdnd,<br />
covsr e xp €ns€,3 fol tbe<br />
f.crr .the ll:b"ona,l. :x --,::.,* :r1;
130<br />
9. R i ' E R E C E 5<br />
,lcharjyo, Lru. and f[.rhapatra,S(.1<br />
9?B)r Return of t.he<br />
ma!sh c!ocodils tSlg!!g4!: palustrls)<br />
Ind i3 n Foraster. !!!(5):385.<br />
Bust3rd.' H.R(1 900)! Thn L:ovt. of Indls CrocodiLe i,I.oJecr. uheetal<br />
33\1/2)' 11-16'<br />
gustald, i1.R. and SInlh, L.A.k,(198i)r Gharlal attacks on nao.<br />
f,. Banbav nat. Hlst- .-oc. ?S(3)r610_611<br />
Ch&block, R.ll.('1 965)r Thd Dov6mofit ol alllgat0t.6 jn Loul€lana.<br />
proc. Ano. Canf. Southeastsrn Assoc. came and FIsh ColIlB<br />
!9! 102-10.<br />
Cott, H.E.(1951)r Scicntiflc rssults of..rn inqui!y j.nto th.<br />
ccology,rnd ccooonlc atatus af thc lrJllo crocodll8<br />
Glocgsltlug nJlotlcqs) in Uganda and Northorn Bhodoelq.<br />
Tfansactions of th6 Zooloolcal Societv of London. 29 r<br />
zL | -Jao.<br />
F.e.0.(1 9?4,)r India. A p!6llaln.rry sulvsy of lhs ploepects for<br />
crocodllo falolrE. (gaeod on th€ urork of O!. H.R.<br />
EustaEd). F& LND/71/o33, octr 1924.1_66pp.<br />
Cro€obrldgs, g.(1 982)r Th€ IUCN Anphibta-ReptltIa Red Data Book<br />
p6rt I r TsstudlnBs CrocEdylia Rhynchocephalla. ItCN,<br />
Chnd, Sultzorlqnd,pp. 363-3?0.<br />
cupta', R.C. and SrlHarl, F(1 989)r 0n thr basking behavl.our of<br />
th6 dugg6! Crocodvlirs palustrls Lonon(Reptilla,<br />
Crocodllla) at tholsainda Clocodlle :anctuary, Halvana<br />
..tat!.<br />
ca Pt iv6<br />
rnti the,rrlld.<br />
J. nombav nat. H1!t. 5oc, 06(Z): 17O_174.
Lanco, V,rr, (1 907) r llorlnon.rl, aontrol ol IBp!oductiun in uruco<br />
131<br />
dillan6. pp 409-415. Int 'jlild.Lif s ltaoao6oent! C!ocodiles<br />
dnd {J.liqqto13 od. by c.J.UJsbb, :.C. li|lna}is and<br />
tr.J. thiteh€ad. Sutvey Ba6tty and ,;ohs plV Lloited<br />
1n a I s o c L a t i o n . u j.<br />
t h th6 C oo6s!vatj.on C omnis sj.ori of the<br />
I srrrLU.y.<br />
Langr J.'J,(1 98?)r Crocodillan Sehaviou!i Implications for<br />
manaq6ment. pagas 2?3-94. in ,JJildll.fs {lhndg6d|ent.1<br />
C!ocodIlos and AlLlgdtoBs. ed. by 6lahame J.UJ,Usbb,<br />
5. Cha!1i,6 manllis and Pet€r f,. Lthitehead:ulvey Beatty<br />
and Sone. pty lioltEd la associatlon luith tho<br />
Con6€rvatl.on Coo6ls6ion ol th. Nolthern Tsr!ltory.<br />
lnurph!, T.(1 902). C1tatl,onrp.16. In. 5lngh, L.A.K.(1905)r<br />
Ghqrlal populalloB. Trond in NatlonaJ' chsmbrl :,ir nct uary<br />
u,Ith. nots6 qo radie tlacking. Covt. of India, Croc,odllc<br />
Reee.rqh Cantls of UJlldlifs Instltuts of Indta. Hyd€sabad.<br />
PP viil + 167.<br />
Rao' R.J. and SirEhr L.A.K.(1 992)rCoomunal oastl,ng of the<br />
gharlal Eavtalis qanodticus (careltn) (Reptilia, Clocodllia)<br />
Ln thE Natlonal chaobal, sanct uarv.Aiggf-3gl-!'d'<br />
J=(i^ P"*)<br />
Rathr R.L.r str€h, L.A,K. sad Karr 5.(1 990): uork plan ?or<br />
arocodll€ managemsnt ln os1ssa.r.Indla durinq 1990-95.<br />
Sagur, S. and 5ir€h, L.A.K.(1 990a)3 Eaptlve Blesding and<br />
rehabil.it.t j.oo of ougger(Crocodvlus glg:!gi: ) in<br />
Slrnilipal T19rt Rcarru€' orissar India. Indian Foreater.<br />
Saga!, S. and Sit€h. L.A,K.(1 992 )r Notes on eurvival efficiency<br />
cnd grolrth of htttshung qug96!(Crocodvlus gf,f.$i!.g)'<br />
@:L!4l!rv''<br />
(3), tYor.r tee2-
132<br />
,-tlr..tlr., L . . ' . ii , ( I | '/ | ) : tuoJ.ulic,rl" -Luu1r,g r..rrr l.lr,; lrrrji..l'<br />
thariall Javi.lig o4n.eticus (tr,relin)(neptllia)<br />
C!Jcodilia). tltkal Univorslty' ilr"J. Llres15.<br />
Singhr L.A,K.(1 9s3a)i Commuoal uss of villags ponds by the<br />
muss €!s ciocod i]u (S::gg34g' lg.lgll-t : ), catt 16<br />
and nEn. .l,Bombav nat. Hist':.:gS. !!(2)r642-645.<br />
SirEh' L.A.K.(1 983b)r Th€ fndian mugger,Crocodvis SLjg3.119<br />
Leror (ReptllialCrocodlLia) r Obsol:vJtions cn th6<br />
behavicur qf a feoa19 from natute. J.tomba'J nat.<br />
.::-]:-!-:-jt9s . jg\r)r 499-506.<br />
5ingh, L,A.K.(1 983c)r 0bservations on the |llovsm€nt of turo<br />
captiu6 rearad mugqor crocodi16sr crocodvlug<br />
palustlis L€sson u/h6n leturned to the '!ild.<br />
J, Bombilv o+li !irg! !qc] C0r,1):u6-90<br />
lingh, L.A.K,(1 9fJ5)i Gharlal Trsnd :n ttatiorel chi.lmbal<br />
Sanctualy ulth notos oo lad1otlacking. Covt.<br />
of India, Cro.codils Resoalch Centle of fildlif.<br />
IostitutE of Indi.ar Hvd€labad. pp.viii + 167.<br />
5inght L.A.K.('1996)lCharactet ol tbe population in Ghdrlsl.<br />
p.362- . 423. J!: A t6chnisal expsdltion<br />
uith Indlan Crocodllee. Ir'15s.<br />
Sirqh, L.A.K.,Chaudhury' B.C. and Kar,5.(1 990)r lndian<br />
ctocodil€s: option and Tasks du!ing 1990s'<br />
pp. 191-198. In:C!ocodiles. I !ocudln'l of tho<br />
9fh Uo!klng lr,€rtlng ol ths c!ocodile<br />
'pecislist<br />
C!oupr 1L[N- Th€ UJorld CooservatLon llnion'<br />
[land, SurltzBrland. Vo1.2.I5BN 2-0317-u009-4<br />
iv + 380.
-:..L, -.i.,.,;:I, 1.. 4,iu ,:1,- j.li:rtr:, .1.i.;. .'<br />
133<br />
:!o!od:1e9: .l 10-ysa! ievi.s'r of idncllsnv,.r:. p. 3a2-3?.,.<br />
_:l :t,Jcccilesi j.!c.oco:n!:<br />
trf ih,, 7:1.: i:t : ,:,,i ii,<br />
Df :ho i:r:)crr.lj1c puclcli:t l::u;r ,jf ' ., I -l , ir! I l:',<br />
:rtaqas-Venezvela, 1944. IUall pu iicJ:ieri .!,J 'd.ies<br />
ISB it 2-08032-3t16-1 . ro(uIlI+44J,<br />
-injl,' L' r,(. and liro' f.J,(1 9eb): i,iljiri:i..rncc f :-uridual<br />
ogg fluj.d to tTdtchfing pattsrn: irr ihc -irr:i:1<br />
G-!f-CU-: ,rdoaoi,icus) 'nd ernydid ftcshuJte! turtL!5<br />
(i.eptj.1iJ, iiocodiiia and ChsIcni{j. ]. iJ,.bn! rdl.<br />
llisr-. :oc- -!ll )r211-22u.<br />
linghr L.A.K. and Sagarr 5.(1990): The escape and captuie of<br />
d muggor c.rocodi.IB(Ctocod\rlul ouLustrl:r) .t (u'nrJti!tho'<br />
0!j.ssc. Indla n i-onester. )16(ro):8ql-S9'1<br />
ThompsooI R.L. and il.dden,C.9.(1 9?2J: T6rrlto!iaI 6a6kinq<br />
count e to s st j,oat s all ig at ol p op uLat 10 ns. -lq!!_!3-1__SI<br />
uJildlile lilar.3qement. 36(4) oct 1972-1081 -1088.<br />
Uebb' G.l.u(1 981 ): NBsting bj.olooy of Drocodvlus j$!$! n i<br />
in ths Northern Territory' Chap, 20. p.l0? in tlanks,<br />
C.B. ano,',;r. Iiartin (eds). ilocesdin(js of thc<br />
L,Elboucne llerp€tological'-ytlPosium. Zoolo! .cal 3oa!c<br />
of Victoria, RoyaI uelbouins U oolog-caI .l.tdans'<br />
!hitake!rn, (1 974): l,lotes on bshaviourr €co-loCr- iind preseot<br />
status of th6 nalsh c!ccodile(croccdvlus;l!E!!j)<br />
south, Indla. A giadlaa 5o€t ka Park Trust l)ubllcatLon"<br />
Uhi.inkorr Hdm and Zo1(1 989)t Ecology ot Lho nrtJ!!cr crocodile'<br />
276-296. In: C!ocodllestTh€1r fcology, [lar|agement ano<br />
Coneslvatlon. A :psclal liubficatlon of the Clocodil'a<br />
5p€clallst 6roup of the '-pec169 Sutvival toiilmis6ion<br />
cf ths InternatlonaL union for consB!v.rtlon of Natu!4.<br />
and atqral Resoulcgs. lUCt\ puolicatlon :leuJ 5cr ies.<br />
ISBN 2-88032-9€?-6. C l.od, Su,ltz6rldnJ.<br />
in
134<br />
Crocoalilian Conservation andl Connsrce !<br />
conDon lDtereats prevail in gustal.ned uae l{allageu€Dt<br />
INTRODUCTION<br />
Uatk A. gtaton<br />
Uainlanal Uolalirgg Crocoalile ?arn<br />
P. O. Box 196<br />
Lae, Papua Nsr cuitea<br />
It is a pleasure to address this llth Working Meeting of the.<br />
IUCN/SSC <strong>Crocodile</strong> <strong>Specialist</strong> <strong>Group</strong> (CSG), In previous sdssions,<br />
we have heard from speclalists on a topic of particular interest<br />
to this meeting - the conservation of croco-dilians in Africa.<br />
Further, rderve heard reports on the status of a nunber of<br />
crocodilian populations around the lror1d.<br />
In todayrs session, we lrill hear a number of talks relatinq<br />
in one way or another to the utj.lization of crocodilian resourcei<br />
around the world. Utilization of a natural resource can of<br />
course nean a varj.ety of things - for exanple, sinple aesthetic<br />
appreciation of witdlife in natural surroundings, tourisn, or<br />
hunting for pleasure and trad€. For rnany large inarnmal and bird<br />
species, populations are nanaged to allow for -hunting - both for<br />
sp9f! ar-rd trade purposes. With crocoditians, resource<br />
utilization is primarily for trade purposes and has been<br />
developed to include not only hunting of vrild populations, i,e.,<br />
I'croppingr', but also the capt.ive nanagement of-individu;ls (o;<br />
theLr.offspring) originating fron the;itd, i.e., ,'ranchinq" and<br />
ifarningtr, to enhance the yield vhich can sustainibly be obtained<br />
fron wild populations, Today. conmercialisn is undoubtedlv one<br />
of the key factors in what is the pritnary concern of this group -<br />
Crocodilian Conservation. The fact that a fulf day -of<br />
presentations on resource utilization is scheduled for todav<br />
bears out this view.<br />
IMPORTANCE OF COI'TITERCIAL FACTORS IN CONSERVATION<br />
wtry are cornmercial- factors so inportant at a conference oll<br />
crocodile conservation? At least for €wo very inportant reasons:<br />
(1) Past coru0ercial activities have to a l-arqe extent<br />
created the probLe!0s requiring conservation efforts and actiong.<br />
As you know, the commercial exploitation of crocodilians has qone<br />
on for approxittately t\ro centuries for their fat oils in -the<br />
early- lsth. ce-ntury, as pets and for neat in this century, but<br />
rost.dahagingly, of. course, for their valuable skins to rnaf.e hign<br />
quality leather, since the nid-1aoo's (see Joanen and McNeas;,<br />
1991,for a revietr). Holrever, cormercial exploitation, in and of<br />
itself, has -not been the problem. The prbblen has 'been that,<br />
until. recentLy, that €xploitation has been unregulated and, tlore<br />
lnportantl-y, unsustainable. This resulted in the severe<br />
depletion of tnany populations of most species around the lrorld<br />
by the 1960rs and created the need for active conservation<br />
meagureS.
(2t The second reason that trade issues are i-mportant here<br />
is that conrnercial activities, vithin a conservation-orientated<br />
franeworkr can represent nuch of the solution to the problerns<br />
created by past unregulated unsustainable trade. Further,<br />
connercial utilization of crocodilian natural resources around<br />
the lrortd can have a positive inpact on the conservation of a<br />
r4'ide variety of species, crocodilian and otherwise.<br />
The view that a positive relationship can exist betveen<br />
conservation activities and the rational exploitation of rrrildlife<br />
as a rene\^/able natural resource shouLd cone as no surprise. We<br />
have, as an example, a historical precedent in the United states<br />
of initially unrestrained exploitation of game species, followed<br />
by the recovery and utilization of their nanaged populations<br />
(Gilbert, 1964i Clepper 1966; Conalray, 1992). In the early 19th<br />
century there existed r4'hat appeared to be boundless natural<br />
resources across the United States. However, during the latter<br />
half of the last century, hunting of game species took place on<br />
a mannoth scale - culminating, for exanpLe, in the extinction of<br />
the passenger pigeon the decirnation of bison and pronghorn fron<br />
the A$erican P1ains and the slaughter of hundred of thousands of<br />
nesting egrets, herons, ibises and other vading birds for the<br />
fashion trade. This should sound faniliar to crocodili-an<br />
conservationists.<br />
By the end of the last century, conservation had becone a<br />
public priority. The Ne\,, York Audobon society was fortned in<br />
1885. Yellowstone National Park and other wildlife Refuges $rere<br />
established. A pro-conservation president, Theodore Roosewelt.<br />
was elected. Forerunners of the United states Fish and wildlife<br />
Service and the United States Departnent of Forestry were<br />
established, and professional vildlj.fe societies lrere born.<br />
state lar's were passed to protect local wildlife, and the first<br />
federal lasr dealing r4rith wild1ife, the Lacey Act, was passed in<br />
1900 - making a federal crine of interstate transport tildlife<br />
taken in violati.on of state laws.<br />
what followed roughly fron 1900 to 1935 has been described<br />
as the rrera of preservation and productiontt. During this tirne<br />
nany once-depl-eted populations rebounded to the extent that they<br />
exceeded carrying capacity and. in some cases. began to selfdestruct.<br />
soon, the problen was not a natter of too little, but<br />
instead too nuch, protection. However, the ideas of preservation<br />
and protection had been nsoldn so effectively that neither the<br />
publj-c nor official-s of wildl-ife agencies could accept anything<br />
contrary as being good nanagernent (Gifbert, 1964). Portunately,<br />
it v,ras durj-ng this period that the pioneer ecologist and wildlife<br />
hanager Aldo Leopold laid lhe foundation for modern lrildlife<br />
nanagement - stating essentially that wild populations produce<br />
rra generous surplus over that needed to maintain adequate stocks;<br />
and that this surpluE can be removed by hunters without<br />
endangering the species. If not used by hunters, it will die of<br />
other causes, some of vrhich tnay endanger the breeding stocks rnore<br />
seriouEly than regulated hunting. Clepper 1966).<br />
135
136<br />
Since the nid-193ors, the vildlife hanagement concepts<br />
pioneered by Leopold and others were lnolded into state and<br />
federal laws governing gahe species, but to varying alegrees. A<br />
recent article in National ceographic (Conaway, 1992) points out<br />
that in sorne cases once-depleted species such as white-tail deer,<br />
wild turkeys. Canada geese, black bears, and yes-even atligatorshave<br />
now becone public nuisances and. in some cases, public<br />
health threats. l,Iore inportantly, Conovray (1992) points out that<br />
rrhunting is an ihportant factor in the success of irildlife<br />
nanagenent proqrarLs. In fact, the fate of larqe aninals is<br />
intinately related to their status as fane..... The pittnan-<br />
Robertson Act levies an excise tax on arns and amnunition that<br />
over 50 years has raised nore than trlro bilfion doflars, nost of<br />
it disbursed to state ]l/ild1ife agencies for popufation studies,<br />
ihproving nitlions of acres of irildlife habitat'r. The articfe<br />
goes to decry that less than 20? of the nonies were spent on nongame<br />
species. However, it should be noted that (1) this is<br />
approxinately US$400,000,000 for species that Iack a obvious<br />
econo)lic value and that lrould have been very difficult to raise<br />
in any other way; and (2) many non-game species benefited fron<br />
the lrildlife habitat that was ihproved, managed and/or purchased.<br />
PROTECTION AND UTILIZATION OE CROCODILIAN RASOURCES<br />
The paralfefs $,/ith the cotnnerciaf exploitation of<br />
crocodilians are rather obvious. As a non-gane species, their<br />
unregufated exploitation continued until the 1960's. Fo1lo\\'inq<br />
severe depletion of crocodilian populations vorldwide, a period<br />
narked by lncreased public awareness of endangered species and<br />
other environmental issues, and legislation to protect<br />
crocodilians species fol lor^/ed.<br />
In the fate 196Ors and early 197O,s, legisfation was<br />
desj.gned to ban hunting of witd crocodilians and/or sate of their<br />
skins or finished products nade froh them. As a consequence, the<br />
early relationshlp betUeen conservationists and the crocodilian<br />
trade rvas inevitabfy an antagonistic one. Throughout the 197O's<br />
and 1980rs, due to the inagination and efforts of a !,ride variety<br />
of people with equally diverse views and interest, an evolution<br />
f^^L hl:-6 ih Uhi^l'.<br />
(1) most in trade have come to appreciate that crocodilian<br />
resources are finite renewable natural lesources and<br />
can be harvested only v/ithin bounds;<br />
(2) nost conservationists have shed a preservationist<br />
attitude and have not only approved, but have<br />
ernbraced, utifization of the species as a resource and<br />
a key to their conservation.<br />
A study of the Proceedings of CSG Working Meeting over the<br />
past twenty years rrould reveal that the CSG has served as the<br />
forum for this developnent.
with the recognition that goals of both conservation and<br />
comrnerciaf enterprise overlap, conservationists. regulators and<br />
industry have developed a cooperative strategy by which selected<br />
(recovered) populations are harvested as a rnanaged reneltabLe<br />
natural resource. central to this scherne. knovh as trsustained<br />
Use ltanagrenentlr, is the concept that this utilization be<br />
sustainable - i.e., within the capacity of the natural resource<br />
to renew itself (IUCN/UNEP/WWF, 1991). The concept is considered<br />
so inportant that an IUCN/SSC SpeciaList <strong>Group</strong> on Sustainable Use<br />
of Wild species has been forned (8. Vernon, pers. conunun.).<br />
Thorbjarnarson et al. (1992) offer an excellent discussion of suu<br />
or sustained yield utilization as applied to crocodilian<br />
resources.<br />
The new relationship between conservationists and industry<br />
dj-d not take place only !'ithin the crocodilian !'orld. By 1980,<br />
the world conservation strategy, developed by IUCN and wwF, took<br />
the position that rrconservation is not the opposite of<br />
developnent. Instead. it lras ernphasized that rrconservation<br />
includes both protection and the ratj.onal use of natural<br />
resources,, (IUCN/ITNEP/WWF, 1991).<br />
137<br />
Parallels can be found in the inplernentation of cITEs, lrhich<br />
took effect in the 1970rs, banning trade in some species and<br />
regulating international trade in other species through systems<br />
of tags, licenses and pernits inplenented by l"ocaL CITES<br />
Uanagenent Authorities. Throughout the years, CITES has been<br />
nodified. and changes affecting crocodilians have generally<br />
reflected a nore tolerant attitude tovard trade, as long as it<br />
lras controlled, legal and sustaj.nable. For exatnple, under Res.<br />
conf. 2.L2t Appendix I species which vere initially banned frorn<br />
trade, can be treated under the provisions of Appendix II when<br />
they are propagated in captivity. Further, a nunber of<br />
resolutions during the 1970rs and 1980rs provided a vehicle for<br />
the transfer of populations frorn Appendix I to Appendix II under<br />
ranchj.ng (Res. conf. 3.15) or quota (Res. Conf. 5.21) programs.<br />
CITES aras able to incorporate pro-utilization concepts .into lrhat<br />
was originally protective regul-ations due to the pro-utilization<br />
stance within CSG, the active input and support of the CSG<br />
lrenbership, the hard work of vildlife agencies and just as<br />
iuportantly, the trade nonitoring activities of TRAFFIC. At the<br />
recent Meeting of the Conference of CITES Parties in Kyoto Japan<br />
( arch 1992). a resolution, Con. 8.3 (rev. 4) that recognized the<br />
benefits of trade in wildlife was approved. Further, the CSG<br />
agenda of using sustainable use to conserve crocodilians lrith<br />
involvenent of the cornnercial trade sector in conservation action<br />
was advanced and may be a model that CITES will apply to a<br />
broader context (CSG Newsletter, Vol. 11 (1), pp. J,3, Li).<br />
CONSERVATION<br />
lnrrthe late 1960!s, virtually every one of the 23 specj-es<br />
of crocodilians iras endangered, threatened, or declining in<br />
numbers. Today, approxinately one-third renain critically<br />
endangered, but one-third have stable or increasing populations,
138<br />
and one-third have sufficiently large populations to support a<br />
rigorously managed Legal harvest. This change has corne about<br />
because of the econonic value of crocodilians. crocodilians are<br />
the best exanple of rvalue driwenr conservationl (Messel, 1991).<br />
Itany successful conservation prograns hawe been built around<br />
the economic value of crocodilians. For example, in Papua New<br />
cuinea, the crocodile Trade Protection Act was desiqned to not<br />
only to protect the crocodile resources of Papua Ner^r Guinea frorn<br />
over exploitation, but also to support a viable industry in vhich<br />
traditional landor^rners could benefit fron and control the harvest<br />
of eggs, live crocodiles and/or ski-ns rernoved fron their land<br />
(Bol.lands,<br />
nations,<br />
198?). In Papua New cuinea, as in other developing<br />
if people lrcan make rnoney by harvesting wild<br />
crocodilians nost viII do so. In subsistence econonies, making<br />
noney is irnportant. "<br />
without the econonic incentive. people are<br />
not wilfing to put up lrith increasingly abundant, crocodilians<br />
lrhich can ehdanger villages or their livestock. (Itessel, 1991).<br />
In venezuela, sone ranchers rrhave earned as rnuch money frorn<br />
harvesting capybara on their land as they do fron cattle. The<br />
caiman add a third species of rlivestockr. which they protect<br />
every bit as much as they do their cattle'r. This also gives thern<br />
rran econonic incentive for conserving the wetlands that support<br />
the caimans and nany adequate speciesrr (Messef, 1991) .<br />
Sinilarly, if coastal landowners of Louisiana and Florida<br />
are given an econornic incentive to rnaintain their property as<br />
wetlands, they vrill do so. They can be given this incentive by<br />
allo{ing them to benefit frorfl their alligator populations -<br />
through, for example, Ieasing their l-and for the cropping of the<br />
l'ild population or the collection of eggs to be used in a<br />
ranching progran - all under a nanagenent prograrn which is<br />
scientificalty, designed and rigorously enforceil (Joanen and<br />
llcNease, 1981; Hines and Abercronbie, 1,9e7).<br />
Most endangered species are endangered not because of<br />
hunting or conunercial exploitation, but because of habitat<br />
destruction and loss to an expanding hurnan population. Placing<br />
value on habitats leads to their rnanagement and protection for<br />
crocodilians and other species. The pronotion of habitat<br />
conservation through the econonic value of crocodilians thus<br />
takes on ihportance in the conservation of non-crocodilian<br />
species. In Florida, an integral part of the staters alliqator<br />
managenent program is their lvalue addedrr concept that "the<br />
conrnercial worth of alligators should be channelled into helping<br />
the conservation of both themselves and their habitats..... It<br />
specifies that the returns derived by the State frorn cornmercial<br />
alligator exploitation shall be used as a source of funding for<br />
the continued managenent of the \,7ild resource. This feedback can<br />
be direct (i.e., supporting researeh or habitat preservation and<br />
enhancement) or indirect (i.e., providing landor4rners with<br />
econonic incentives to preserve their vetland) I (Hines and<br />
Abercrornbie. 1987 ) .
RESEARCH PRIORITIES AND SCIENTIFIC BENEFITS OF SUM<br />
Control-led. legal trade r^ras thus allowed to proceed and<br />
expand as l-ong as vhat resulted fron SttM prograns did not darnaqe<br />
the natural resource. i.e., as fong as utilization lrts<br />
sustainable. Central to this concept is that it be dernonstrable<br />
that crocodilian populations are not being depleted. Thus, the<br />
val-ue of the monitorihg efforts cannot be overstated. It is of<br />
great irnportance to trade and conservation interests alike that<br />
monitoring methods be accurate and efforts to continually irnprove<br />
these rnethods should be encouraged.<br />
It is therefore not surprj-sing that population nonitoring<br />
has been a high priority for funding by the industry.<br />
Thorbjarnarson et a1. (1992) point out that rnuch of the fundi;g<br />
in recent years for crocodile conservation has been nade<br />
available by the reptile leather industry - and huch of this for<br />
surveys or to heLp irnplement SUM p1ans.<br />
The cornmercial iroportance of crocodilians, and the fact that<br />
their exploitation under suM programs is based on scientific<br />
principles, has lead to a remarkable expansion in the scientific<br />
knowledge of crocodilians. Anyone who has conducted a literature<br />
reviev recently viLl be struck vJith the diversity and volurne of<br />
knovledge on the biology of crocodilians which hls enerqed over<br />
the Iast 10 to 15 years - at the same tine that, and larlely are<br />
result of, SUI!{ prograns ra'ere being irnplemented vith recovered<br />
crocodilian populations around the $ror1d. A randoh perusal of<br />
the literature vrould show steady increases in the kn;lrledge of<br />
diverse areas such as:<br />
- endocrinology and nervous function<br />
- behavior and stress physiology<br />
- nesting ecology and vildlife nanagenent<br />
- rnetabolisrn and the inportance of ternperature on a1l<br />
aspect of developrnent<br />
- nutrition and feeding<br />
- embryology, norphology and developrnental anatomy<br />
- genetics and systematics<br />
- diseases and veterinary care<br />
- grovth rates and aqing techniques<br />
- husbandry and captive propagation techniques.<br />
This list is not exhaustive and could obviously be expanded.<br />
While it i-s true that nuch of this inforrnation has'resulteat froit<br />
studies on species of cohmerciaf inportance, nuch of the basic<br />
crocodilian biology can be related to rarer species. This<br />
indirect contribution to the knor!,ledge of the rarer species<br />
should not be rninirnized.<br />
TRADE ISSUES<br />
The track record estabLished through SUM prograrns is one<br />
that the csc nernbership can be proud to have toniributed to.<br />
However, we cannot lrrest on our laurelsr - there are norar and will<br />
be j-n the future new challenges to neet. one need only peruse<br />
't39
t4D<br />
the pages of the CSG neltsletter to read about sorne of these<br />
Lssues. The remainder of this presentation will examine sone of<br />
the issues relating to trade. As lre begin to focus on current<br />
trade issues, bear in rnind that lthat is good for legal controlled<br />
trade will be good for conservation, so these are issues of<br />
concern to conservationists as vell as to businessrnan.<br />
lilarkets and Prices. --- Aside fron illegal trade, which will<br />
be discussed below, several factors are placing great pressure<br />
on the prices of crocodilian skins - (1) Iimited size sel-ection<br />
of increased supply of skins coming fron farn production, (2) the<br />
ongoing stagnation in the world econony, and (3) conpetition fron<br />
other exotic leather industries.<br />
It is no secret that the volune of classical skins coning<br />
on to the narket is increasing. Production of classical skins<br />
world-lride was approximately 150,000 in 1989, 250,0oo in 1990,<br />
and was estimated to reach 300,ooo in 1992 (Lunnore, 1990, pers.<br />
contlun.; Ashley, 1990). the j.ncrease in volume of skins has<br />
resulted alrnost purely fron ranching and farrning prograns. while<br />
skins fron these sources have the advantage of represehting a<br />
steady suppLy of legal skins, the size selection available is<br />
Iinited. targe volunes of skj.ns in a linj.ted size selection has<br />
had a detrimental effect on prices.<br />
The lrorld economy for the last fe!, years has been in a<br />
general recession, uany, including sorne Japanese, say that the<br />
I'bubble has burstl on the econorny in Japan - which is the<br />
ultihate narket of an estimated 70* of the 6kins produced<br />
lrorldwide (Ishii, 1990). There are sinply fer!'er people vilting<br />
to pay the high price of the finished products made frorn<br />
crocodilj-an skins. And, sales to those people are being pursued<br />
aggressively by other leather industries such as fish, snake,<br />
lizard, shark, el-ephant, enu and oslriqh.<br />
The combination of these various factors has lead to a drop<br />
in prices over the past year or two, sone nore drastical-ly than<br />
otherE, but gtenerally betveen 30 - 50t for salted skins. Even<br />
prices for crocodylus potous skins are currently under<br />
considerable pressure.<br />
Inpact on Producers and qradj-nq standards. ---The prevailing<br />
conditions have created a rtbuyerrs narketrt. Not surprisingly,<br />
standards of qrading have becone much stricter over the last 1-2<br />
year6. fn sone cases, skins that would have been purchased as<br />
grade 1 in 1989 at high prices are today being bought as Grade<br />
2 skins at lower base prj.ces by the sarne buyers. This is perhaps<br />
natural but it is also destabilizing to such a younq j.ndustry -<br />
one rdhich was encouraged to grow by the leather industry. As<br />
part of a naturing industry, I believe that produc€rs and buyers<br />
of skins need to cornmunicate better on their mutual technical<br />
problerns and work to arrive at fair and equitable standards and<br />
r0ethods of grading skins - vrhere the conmon denoninator wiII be<br />
the quality of finished skin. Perhaps a more quantitative and<br />
technical approach to grading vould be appropriate.
The future: Expandinq the Market for crocodilian skins.---<br />
Due to the I'down cycferr in the narket, increases in skin<br />
production appear to be continuinq at a nore moderate pace.<br />
Nevertheless, the availability of classical skins lrill no doubt<br />
continue to increase, Producing those skins for exPanding<br />
markets nill be good for both conservation and trade, but only<br />
if they are sold at a fair and profitabte price.<br />
How do rre get our rnarkets to expand? one thing r1'e can do<br />
is to ra'ork on the narke! at the consur0er level. The 'rpoint-ofsaLesrr<br />
narket.ingr research and promotion bookLet spearheaded by<br />
Don Ashley is an excellent exanple of the type of approach the<br />
industry rnust take in order to influence the market at the<br />
consuner level (Ashley, 1990b).<br />
There is an urgtent need to address and correct the<br />
perception that nuch of the general public - read that the<br />
"buyi-ng public" - still has of alligators and crocodiles. There<br />
are still a great nany people who believe af1 crocodilians are<br />
endangered. Consequently they belj.eve (1) that it is unethical<br />
and anti-conservation to buy an alligator or crocodi.le skin<br />
product, and/or (2) that it nay be illegal. to purchase all<br />
crocodilian skins products.<br />
141<br />
For example, in the 17 June 1992 issue of a Lafayette,<br />
Louisiana newspaper (Ihe Daily Advertiser, p.13), an article<br />
about the cuban crocodj.le stated that "v,torldwide pressure is<br />
being focused on cubars endangered crocodile progralr because the<br />
island nation has joined a treaty organization that stops<br />
peddling of ivory tusks, cheetah skins and crocodile productsrr.<br />
The article not only puts all crocodile products in the sarne<br />
category as ivory products - which have received nuch negative<br />
publicity, it implied that cITEs bans the sale of all crocodile<br />
products as r,retl. Irresponsible staternents and half-truths like<br />
these undoubtedly cost our industry sales.<br />
As another example, an article about a IFur Amnestyrt proqrant<br />
promoted by a group called "rn Defense of Anirnalsrt recently<br />
appeared in the tlall street Journal (9 January 1992). The<br />
president of the group was encouraging people to give up their<br />
fur coatg and stoles - by donatinq thern to the group so that they<br />
could rrparody those rrho think they look beautiful in fur.I This<br />
vould not appear to affect our industry - indeed, the text of lhe<br />
articfe mentj-oned not one word about crocodiles or alligators,<br />
and the rramnesty progranrr lras clearly aimed at the fur industry.<br />
However, the titl-e of the article was "Ge! Ready to send Hj-m your<br />
old rvory Brooches and Alligator Bagsr. The inpression left on<br />
the reader - by the stringing toqether of negative inpressions<br />
of furs, ivory and crocodilians products - undoubtedly costs our<br />
i.ndustry sales.<br />
The nessage to the public in late 1960rs and 197ors was that<br />
crocodilians lrere endanger€d and needed protection, and this<br />
loessage was appropriate at that tine. However, as lrith qane<br />
species in the years following recovery of depleted popuLations<br />
in the 1930rs, todayrs nessage about crocodilians desperately
42<br />
needs to be updated to ineet present-day realities. Misconceptions<br />
rnust be addressed with the assistance of conservationists, as the<br />
sane nessage corning only from the trade vtilf lack credibility.<br />
The csc is and should be prinarily concerneal with the<br />
conservation of crocodilians. However, the csc has enlisted the<br />
legal trade as a tool in the conservation of crocodilians. The<br />
csc should therefore take the lead in inforrning the public that<br />
only some crocodilians are endangered, tha! many crocodilianE<br />
populations have recovered and produce sustainable yields under<br />
well-managed stM prograns - in short, that buying legaI products<br />
supports crocodilian research, supports crocodilian conservation,<br />
supports habitat conservation? and supports an j'ncreasingly<br />
environmental Iy-f riendly industry.<br />
chandino structure of Industrv. ---The structure of the<br />
industry will undoubtedly continue to change with the increased<br />
proportion of skins corning fron the farning and ranchinq sectors<br />
- an essentially agricultural pursuit - as opposed to cropping<br />
prograns, vhich have dominated the supply of markets in the past.<br />
As ra'ith other agro-industries, it seerns likely that this<br />
aqricultural conponent of the industry will seek (1) to expand<br />
narkets for products rnade fron farmed crocodilians skins, and (2)<br />
to benefit fron that expanded narket, not only through the sale<br />
of their skins but through obtaining a portion of profits which<br />
nornally gto to those invotved in the processing, manufacture and<br />
narketing of the finished products. That can be done by<br />
following the exanple of other livestock industries - lrhere joint<br />
ventures, partnerships or single conpanies enconpass the various<br />
subsectors of an industry, starting, for example, !.rith breeding<br />
stock, producing livestock and narketable products, and retailihg<br />
then. In the case of the crocodilian farrling and ranch-ing<br />
industry, we !'ould start with breeding stock or a ranched egg and<br />
market handbaqs - al1 within the same conpany or group of<br />
cornpanies working together. This would bring a greater share of<br />
the profits to producers - rho suffer nost during market down<br />
cycles like the one we are j.n no!t. It seems likely that those<br />
who vrill do best in this industry over the next decade are those<br />
who are able to integrate the activities of skin producers and<br />
tanners together with those involved in the manufacture and<br />
rnarketing of crocodilian skin products.<br />
Ifleqal Trade. ---The Iegal crocodilian farming and skin<br />
trading industry contributes to, or accounts entirely for, the<br />
Livelihood of thousands of people. Landovrners, vill'age<br />
suppliers, egg collectors, skin hunters, farmers, wildlife<br />
officials, researchers, abattoir and tannery !,rorkers, leather<br />
goods nanufacturers, retailers, investors and others all<br />
aontribute to the legal industry in one way or another. As this<br />
legal industry vorks to produce skins and meat, and expand<br />
markets, it is also building a conservation base for crocodili.ans<br />
and their habitats. Thus illegal trade constitutes a thorn in<br />
the side of thousands of people involved in the trade and<br />
conservation of crocodilians. It is rnost unfair to industry and<br />
counterproductive in nore than one way to conservation efforts<br />
to allovr even one illegal skin to filf a sale that \irould other<br />
wise be filled '.rith a leqal one.
As anyone \4rho reads the CSG newsl.etter knows, il-legal trade<br />
continues, but great strides have been taken to curtail ifleqal<br />
trade in the last few year. Probably the greatest remaini.ng<br />
probletn is ill.egal trade in cairnan skins. For exarnple, in 1990-<br />
1991, at a tirne when the trade in Cairnan crocodiTus skins froh<br />
a1l legal sources lras approrirnately 200,000 per year, at least<br />
tvice that nunber were traded iIIegaIIy. A single shipnent of<br />
approxirnately 250,000 skins lacking legaf documehts was shipped<br />
fron this island in Septernber 1991. The CSG has taken steps to<br />
address this issue by lrriting to appropriate authorities, and<br />
hopefulLy this situation r,rill be resolved soon. rrThe issue with<br />
Cainan j-s perceived to be a question of 1egality, not one of<br />
conservation needs.rr (CSG Newsletter, Vol. 10(4), p. 14).<br />
Although by definition, illegal trade in Cairnan sklns is<br />
counterproductive to the conservation efforts of producer<br />
countries in Latin Anerica, the CSG steering conrnittee considers<br />
that the I'key issue is that illegal skins are unfair conpetition<br />
for legal skins because the cot of production is Lor," and that<br />
therefore illegal trade underrnines legal sustainable use<br />
nanagement and threatens the legal traderr (CSG Newsletter VoL 10<br />
(4) p. 14) .<br />
Il-legal trade does not take place vithout the knowledge of<br />
importers in the receiving nations. The actions of such<br />
irnporters are in turn governed by tegislation available to CITES<br />
lnanagenent authorities in inporting countries. Problerns emerge<br />
lrhere that supporting legislation does requj-re effective<br />
j.nplenentation of CITES. The CSG is actively involved in both<br />
encouraging strict CITES inplenentation and rnonitoring the action<br />
of governmenl in this regard. The fact that Si,ngapore has<br />
Iifted its reservation on inconing Cainan crocodiTus skins is<br />
considered a very positive developnent. Hovever, there are still<br />
serious concerns about exi.sting stockpiles - for which plans to<br />
inventory and account for these skins are stifl forthcorning. (c.<br />
Hinley, pers. cornmun.; CSG Newsletter, Vol. 11 (1) , pp. 5-6).<br />
Another serious problen has been poor irnplernentation of CITES<br />
by Italy (CSG Nelrsletter, Vol. 11 (1) p. 9). As a result, a<br />
CITES standing Conmittee has recentfy reconmended that all CITES<br />
parties ban vrildlife trade lrith Italy (c. Hernley, pers. cohrnun.).<br />
Such rneasures are both drastic and unfortunate - particulary for<br />
those in ltaly vrho trade le9a11y. Nevertheless, such steps are<br />
necessary to prornote leqal trade by ensuring cornpliance vith<br />
CITES by crocodilian industries throughout the world. Similar<br />
pressure on Thailand has recently led to serious conservation<br />
neasures and efforts to inprove conptiance with CITES in tha!<br />
country (CSG Nevsletter, Vol 11 (1), pp. 8-9).<br />
Universal Tadqind. ---For several year, universal tagging of<br />
crocodilian skins and the products rnade fron theh has been under<br />
serious discussion as a neasure in the regulation of trade<br />
crocodilians and particularly as a measure to control ilfegal<br />
trade. At the Santa Uarta, Colombia rneeting of the CSG Steering<br />
Corunittee, this group gave its approval to a proposal, which had<br />
been developed by the CITES Anirnals Cornrnittee, u'hj.ch called for<br />
a universal tagging systen for identification of crocodilian<br />
skins. Tagging of finished products made frorn crocodilian skins<br />
1,43
I44<br />
tras considered both inpractical and unnecessary/ a6 it was<br />
recoqnized that tanneries and nanufactures are suitable points<br />
of control-, and tagging up to these stages was recomnehded.<br />
At the meeting of the Conferehce of the Parties of CITES in<br />
Kyoto, Japan (March, 1992), a resolution (Com. 8.23) was passed<br />
which effectively calls for the inplernentation of the cscsupported<br />
proposal and which basicafly applies the tagglng system<br />
that has been in wide use for farmed skins to aII skins in trade,<br />
including cairnan skins (CSG Nevsletter, Vol L1 (1). p. 13-14.<br />
The resolution effectively calls for a universal aging systen for<br />
the identification of alf raw and processed skins and parts<br />
thereof, including chalecos. flanks, bellies/ taiIs, throats,<br />
legs and feet. These tags ar€ to be applied in the country of<br />
origin and naintained, even during possible re-export, through<br />
the point that substantial processing and rnanufacturing has taken<br />
place. l.{ain features of the taqs are that they be self-locking,<br />
nonreusabl-e, resistant to heat and to the chenicaf and mechanical<br />
strasses of processing and nanufacture. Information on the tag<br />
i6 to be perrnanently stanped and include a unique serial<br />
identification nunber, year of export, and encoded data on the<br />
species and country of origin. The resolution also calls for the<br />
infornation on the tags to be replicated on the appropriate<br />
permits, records an annual reports. Further, the resolution<br />
calls for registration and licensing of irirporters and exporters<br />
and addresses the cost of inplenentinq and adninistering the<br />
system (CSG Nelrsletter VoI 11 (1), pp. 10, t2-13.<br />
The ne!, tagging systern is to be inplenented by June of 1993.<br />
At the request of the CITES Anirnals Cornhittee, the CSG has<br />
undertaken the task of developing the new tag, presenting it to<br />
CITES and the rnanagternent authorities and consuner countries.<br />
Development of suitable tags j-s underriray, with the direct<br />
involvernent of several CSG nenbers, notably F. Wayne I(ing and<br />
John Hutton. Part of the rationale for CSG .involvenent is that<br />
the development of the tag by CSG can serve as vehj,cle for the<br />
generation of funds for crocodilian conservation is under<br />
continuing dj-scussion. some of the problens faced by those<br />
developing the tags include (1) nationaf lalrs in sone countries<br />
require that locally produced tags be utilized, (2) establishing<br />
patent rights and hanufacturing processes, and (3) developnent<br />
of a suj-table licensing agreement vrith a rnanufacturer or group<br />
of rnanufactures. obviously rnuch renains to be done in the less<br />
than one year renaining before inplementation (P. Ross, pers.<br />
collnun. )<br />
The development of the universal tagging systen nay be<br />
vielred by some as another layer of regulation - r^rhich nany in<br />
trade frequently consider undesirable. However, the universal<br />
and standardised tagging systern should be rnore properly vier^red<br />
as a giant step in the control of illegal trade. This carries<br />
benefits for our industry which far out{eiqh any problems<br />
presented by this additlonal regulatory neasure. Renovingi<br />
illegal skins from the trade will turn over rnarkets to the legal<br />
trade. where it rightfully belongs. It is perhapg of even<br />
greater consequence that ridding our industry of illegal trade
\'iII inprove our image with an environrnental ly conscious buying<br />
public and increase the number of consuners who wiII purchase our<br />
producers. This lrill advance the cause of those involved in both<br />
the trade and the conservation of crocodilians.<br />
Farrnins Species Bevond Their Natural Ranqe ---- This issue<br />
tlas enrerged several tihes in recent years, and a nunber of<br />
objections have been raised. Objections include concerns (t)<br />
that escape of exotic crocodilians being farrned outside their<br />
natural range could have disastrous ecological inplicalionE for<br />
Iocal fauna, and (2) that establishnent of farninq and trade in<br />
a species beyond its natural range - and therefore, very probably<br />
beyond the jurisdiction of enforcernent agencies overseaing CITES<br />
inplenentation for the species - could serve ttas a conduit for<br />
illegal tradel (Ietter frorn prof. llessel to the United states<br />
Secretary of the Interior, reprinted in the CSG Newsletter, VoI.<br />
10 (4) , p. 13).<br />
Recently, l9O C. niLoticus exported fron Zanbia to Spaid<br />
have presented a problen. Although they vere legally inported<br />
into Spain, the Spanish nanagenent authority rnrithdre; approval<br />
because rrthey were being poorly rnaintained". possible solutions<br />
to the problen are euthanasia, connercial use of the animals, or<br />
their return to Zarnbia at the expense of the Spanish authorities<br />
(CSG Neersletter, Vol. 10 (4), p. 12). This iflustrates that the<br />
farninq of crocodiliang beyond their natural range nay not always<br />
go according to plans, and nay present unusual problems for local<br />
CITES rnanagenent authorities. Such concerns. as well as the<br />
potential ecological and illegal trade problens discussed above<br />
should not be rninimized and require contj-nued attention by the<br />
csG.<br />
SI'MMARY<br />
The foregoing discussion highlights sone najor issues being<br />
faced by the trade and crocodilian conservationists. I.tany others<br />
exist and are being addressed in one vay or another at ahis cse<br />
neeting. with the naturation of our industry and the stillgrolring<br />
recognition that the interests of thost involved in both<br />
legal, sustainable conrnercial activities and crocoditiah<br />
conservation coincide, it has becone possible for people of<br />
different and once-conflicting objectives to i/ork jointly and cooperatively<br />
to pronote what is in their interest - recovery of<br />
crocodilian populations around the worfd and cornrnercial<br />
expl.oj.tation of these recovered populations under sustained use<br />
of nanagernent plans. This approach will ensure continued<br />
successes in crocodil.ian conservation, continued increases rn our<br />
knorledge of crocodilian biology, and expansion of our industry<br />
and trade. As in the past, the cSG has a vital rote to play in<br />
the future of crocodilian coitmerce and conservation.<br />
ACKNOWLEDGI,{ENTS<br />
I gratefully ackno\rledge the conments of perran Ross, Ted<br />
,toanen. cinette Hi.nley, Richard Luxmore, Don Ashley, Brian Vernon<br />
and David Wilken in the preparation of this presantation.<br />
145
146<br />
LITERATURE CITED<br />
Ashley D. 1990a. Monitoring tools: how far do lre go? In<br />
glgggrtileE Proc. loth Working Meeting, IUCN/ssc csc<br />
ueeting, Gainsville, Florida, April 1990. vol. 2, pp<br />
3LL-3\2 .<br />
Ashley D. 1990b. Market production and IAcTs review, In<br />
glgggltlles- Proc. 10th working l,leeting, IUCN/ssc csc<br />
Meeting, cainsville, Florida, April l-99o. vol. 2, pp<br />
318-319.<br />
Clepper, H. 1966. or.igins of Anerican conservation. The<br />
Ronafd Press co,, New York. 193 pp.<br />
Conovray, J. 1992. Eastern uildlife: bittersvreet success.<br />
National Geoqraphic 181(2) : 66-89.<br />
Gilbert, D.L. 1964. Public relations in natural resource<br />
nanagernent. Burgess PubI. Co., I'linneapolis, IVIN. 227 pp.<br />
Hines, T. and C.L. Abercronbie. 1987. The manaqement of<br />
alligators in Florj.da, usA. In wildlife nanadenent :<br />
crocodiles and allioators. G.J.w. Webb, S.C. ltanolis, and<br />
P.J. Whitehead (eds). surrey, Beatty and Sons Pty. Ltd.,<br />
chipping Norton, 2170, Nsw, Australi.a, pp. 43-47,<br />
Hollands, M. 1987. The managenent of crocodiles in Papua NevI<br />
cuinea. In wildlife nanaqenent: crocodiles and alliqators.<br />
c.J.w. webb, s.c. I'tanolis, and P.J. Ltd., chipping Norton,<br />
217o, NSW, Australia, pp.73-89.<br />
Ishii, N. 1990. Global rnarket perspeclives: Japanese narket<br />
inplications of species and size class changes in the<br />
crocodilian trade. fn <strong>Crocodile</strong>s, Proc. 10th Working 1990.<br />
vol. 2, pp. 322-326.<br />
IUCN/I'NEP/WWF. 1991. Carinq for the earth. A strateqy of<br />
sustainable living. rucN/UNDP/wwF, Gland, switzerland 228<br />
Joanen, T. and L. llcNease. 1991. Managernent of the alfigator<br />
as a renewable natural resource in Louisiana. Ga. Dept.<br />
Natural Res. Tech. Bufl. 5162-72.<br />
Joanen, T. and L. llcNease. 1991. The development of the<br />
American alligator industry. Proc. Intensive Tropical<br />
Anirnal Production seninar, Tovnsville, Qld., Australia,<br />
August 1991, pp.9-28.<br />
Luxnore, R. 1990. Internationaf crocodilian skin trade:<br />
trends and soulces. In crocodiles, Proc. 10th working<br />
Meetingi. IUCN/ssc csc I"leeting, Gainsville, Florida, April<br />
1990. Vol. 2, pp. 3O2-305.
Messel, H. 1991. Why sustainable use? (A letter to the<br />
editor of Wildlife Conservation Magazine). Reprinted in<br />
Proc. Synposium on conservati.on and Utiliiation of<br />
wildlife, part If, World Environment and Sustainable Use,<br />
Tokyo, Japan, 3t l,{ay, 1991, pp. 22-30.<br />
Thorbjarnarson, J., H. l"tesse1, F.W. King, and J.p. Ross, 1992.<br />
<strong>Crocodile</strong>s. An action plan for the-ir conservation. IUCN,<br />
GIand, Slritzerland. 136pp.<br />
14'7
148<br />
The Infllr:nce of Dietary Prawn on l-he Produ(it.iol Pe.for.oance<br />
of Yorng Saltwal-er <strong>Crocodile</strong>s (C|.ocodyfus I,oro.sus )<br />
Mark A. Slalon, Rri?rn P. Vernorr and Bange Ilon<br />
l.Jeri nland Hofdings <strong>Crocodile</strong> Farm<br />
Lac,<br />
P. O. Box 196<br />
Papua New cui ne;r<br />
Three shor"t-tern (2, 5 and 6 weeks) experinenls wef(j<br />
conduct,ed to det.erniDe the influence of dief,ary pr:rrn orl l-he<br />
production per.forDance of young (&verage iniLial botly<br />
weigbt-s of 55, 255.and 126 grams, respectively) Saltwat-er<br />
<strong>Crocodile</strong>s (Crocodyfus porosusl . Marine prawn of varaous<br />
spe(jjes were added al- lavels of 43,23 ^ d 20X of dirlL {!!et.<br />
natter basis), respective-ty. In all three experirneil.s,<br />
crocodiles fed prawn-co'ttai n ing diets tended to consume nore<br />
feed. However, body eeigbt gains of crocodiles fed prawncontaining<br />
diets were no greater lhan, or significantly less<br />
than, those of cr'ocodilas fed the control diets, Dry natter<br />
feed conversion by crocodiles fed Lhe prawn-conlraining dieLs<br />
eas significanlly poorer than that of crocodi]es fed the<br />
control d iets.
Distlibution, population structu!6 and som€<br />
ag€ects of the ecology of the estuarine<br />
crocodil€<br />
.lCrocodylus l'o.rosus S chneider<br />
j'n )<br />
the KIias River, Saban<br />
Robelt. B s.tuebing<br />
Shahrul Anuar Mo.trd. Sah<br />
Biology Depa.tnent<br />
Uniwe!si!i Kebanqrsaan Ma]aysia,<br />
Sabah Canpus<br />
88996 Kora KinabaLu<br />
The estuarine crocodile lCracodylrs porosus Schneader) as w1de1y<br />
distributed from rhe e.s! coas! of rndia r; rhe northern Austratia, and<br />
usuall.y, though not exctusivety found in rivers un.ter tidaf inrruence,<br />
where sal:nity ranges from abour 5 - 20 o/oo (Messet, et at., t9s1). rn<br />
southeast Asia, irs conselvaiion srarus is uncextain, though genexatly<br />
assuned to be endanqered (croonbridge, 198?). Snatt scat-e crocodlle<br />
surveys in areas such as the Andanan rslands (rrrhitaker anal whaEaker,<br />
1918), have reported iarher 1ow nurbe!s. white no recenlly published<br />
data are avairable from peni.sular Mat"aysia, ,thitaker (19S4j i; a;;;<br />
and Cox and corLbek (1985) in Sarawak repolted rha! Ctoc.dyjus porosus is<br />
seriously threarened. sEuebing, er al. (1990) , Iro"".... to""O u<br />
substantial poputation in rhe Ktias Rive! in southwest..,., S"tun, u.O<br />
suggested lhat poor survey lechnaques such as brief coverage of rarhe!<br />
extensive aleas (because of Line constrainrs), nighr have grven<br />
misleading resutts _<br />
In depth ecotogicat research on ciocodiles in Ausrratia Deqan rn<br />
1973 (Webb/ 1985), and continued through lhe 1980s. DisLriburion sluaties<br />
showed tha! breeding poputarions of crocodiles inhabjied bor11 tadar<br />
raveis and freshrarer $h'anps. \tuvenite crocodites wer:e found ro feed on<br />
clustaceans and insects (Taytor, 1979). and nigrare upstream from their<br />
nest sites, thoug.h the rnovernenrs w€re nor correlarert wirh fac!o!s such<br />
as salinily (Maqnusson, 1979). subadult C. patosus (> 1.2 n) orsappear<br />
flom breeding locatities or ,'Type<br />
r" habi!ars, apparenrly excfuOea ty<br />
the assresdive behavior of tarser in.lividuar. iri".."r ;nd vorricek;<br />
1987).<br />
In Sabah, crocodiles have been lecorded mainty flom estuarlne<br />
areas, plancipally mangrove habirars along !idat rivers, thouqn cnere<br />
are repolts flon at teast 100 km jntand (T. Lamb, pers. conm.)-rhe<br />
eltensive surveys done in the 1980s in sararak Oy cox ina conbek (19S6)<br />
and in sabah by whitaker (1984) and Kusuadi (1t85) qave genexalty tow<br />
populalion estimares. Furrhelmore, beyonat iough app.oiimations of<br />
abundance, lir!1e ecotosicat infornari;n ..r."i"t"j'c. p...r".<br />
acquiled. stuebing.et a_t. (1990) studied rhe disrribution oi c. p,,o"," "r"<br />
in the Klias River in sourhwestern Sabah, and showed that lhe Klias<br />
possessed a clocodile popularion density comparabte to thar round in<br />
some northern Aust!aIian rive!s. Since this ea!tier Ktias wor:k<br />
distinguished only three separare clocodite size cfasses, dara on !ne<br />
149
150<br />
dislribulion of the warious size cfasses was anriguous. There was also<br />
no dt!emp!. nade co capcure juveniles, or inv-sLigaLe rheir diel -<br />
Since Lhe vdlue of lorq Lern sLrvey work has been pLoven in<br />
Auslralia. an effort has been made to iniriale sinilar srudies in<br />
Malaysia. Long-term sludies furnish a far greater depth of understanding<br />
than do brief, extensive surveys (S!uebing,et af-, \990). The purpose<br />
of Lhe ptesenL uolk is lo flovide d no!- de ailFd picLJle ot Lha.cology<br />
of Cracodylus porosus fron the Klias River, in order to pelhaps qain<br />
insighls into its ecology and behavior elsewhere in Bolneo-<br />
.IIE--STUDIjBEA<br />
The Klias River is located in lhe southwest corner of Sabah,<br />
becween 5o18,N - 50 25.N to 1150 23'E - 1150 55,E approxinately 80 km<br />
flom Kota Kinabalu (Figure 1). Mlaverses approlinatefy l0 kn havinq a<br />
maxinum depth of aboul 16 m, and : tidal fluclualion at km 0 (Kanpunq<br />
Kota Klias, about 50 km flom the south China Sea) of about 2.5 m. The<br />
riwer meanders Lhlough peal swarnp rorest fo! about 60? its lenqth before<br />
giadlnq into upper nangrove vegelalion dominated by Rhizophora apiculata<br />
at approxinately km 12 (downstrean from Kota KIias) changing rathe!<br />
quickly between km 24-2'l Lr\ta a shoreline dominated by Nipah (Mjpa<br />
t tucLicahs) he'e reie 'Fd Lo es \e rowe narorove lobiL4'. Drling -he<br />
wet seasons (Novenlcer-,ranualy and May-July), the riwer naintains a dark<br />
coffee color, beconing increasingly greenish with rislng salinity durinq<br />
the dry season (February-Apxil).<br />
Aquatic<br />
inverLeb!aLe<br />
]ife is typical of nanqiove, with a nultitude<br />
and rjsh spac-ies invao-n9 he es' ua!y du!in9<br />
of marine<br />
hign -ide.<br />
Marine prawns such as Peraeus and Ca.idira sp..ale nunerous duling and<br />
imediately following wet nonths, whrle large freshuaLe! prawns<br />
ltiacrabr.chiun lasenDeLgji) b,.eo .n .bJndan-p clurrng Lhe early dry<br />
nonths (March-April).The manqrove crab lscylla seiraca) is comlnon. In<br />
spite of the apparen! abundance of nunerous marine fishes/ the rnost<br />
coiunonly caught species is a mangrove catfish (ADus sp.). The area is<br />
rich in sj lo.-i er (see wel.ls, er o,,/ lot)). rne tro,L p oainerL bird<br />
species are s!ork-bilted kinqfishers (Podargropsjs capensjs), bulbuls<br />
(Pycnonotidae) and qreen inperial Pigeons (DucuIa aeneaj. The two nost<br />
comnton primate species are lhe long-lailect nacaque (Macaca fascicu-rarjs)<br />
and proboscis monkeys (Nasalis .lalvatus), though the nunnlers of the<br />
latler appear to have declined over the fas! few years. The Klias nay be<br />
classified as a Type I !iver,e.9f., possessing sui!able bieeding habiLaL<br />
tor crocodiles<br />
The (Iias<br />
(Messe1, et a.l. 1981; ScLrebing. eL al., I990r.<br />
is connected via smalle! channels to the Padas Damir<br />
River system to the south. The western two-thirds of lhe KIias Peninsula<br />
previously fotned the Klias National Palk, which was gazetled in 1978<br />
and degazetted in 1983 (whitaker, 19B4) . Several locations about 15 km<br />
downstream fxom Kampung Kota (Iias were previously inhabited, but nost<br />
have been abandoned since 19?5. An estimaled 500 people nod live in the<br />
Kota Kl ids oreo. Piver cr."ic con,-sts rdinlr or Lne snull sampans of<br />
elderly<br />
ca!lying<br />
people who carry out subsjstence fishing.<br />
flom !hree<br />
-o<br />
siy pe.>o, s e F occasionatly<br />
Moto!ized boats<br />
seen L!dveIling<br />
eithe! to o! from coastal fishinq orounds.<br />
VITFRTAT,S AND METHODS<br />
A tolat of 14 spotlight surveys rere nade flom June. 1991 - April,<br />
1992 a1on9 a 37 km stre!ch of the Kfias River west-southwes! fron<br />
Kanpu.ng Kota Klias (Fig.1). This sane area, bordered downstleam by the<br />
mouth of the Sinapokan River, was surveyed in!ensively in 1987-88 by
Stuebing, e. al. (1990) . counts eere nade once pe! nonth, except during<br />
DecenLer 1991 (thiee surveys) and Janua.y 1992 (two surveys). Surveys<br />
were carlied out ar low tide at night (1900 - 0600 hrs) fronL a 4 m long<br />
fibelglass boat powered by a 25 hp Evinrude outboard engine at a speed<br />
or approximaLeLy ls kn hr-i. Because o ne L:r;ng or lhe L-des/ surveys<br />
were begun from June - October at Kuala Sinapokan {km 37) a!<br />
approxinately 1900 hrs. while surveys fron Decernbe! through April set<br />
out fron (9. kota Klias (km 0) at approximalely 0200 hrs. Two obselvers<br />
each using o l2v, 100,000 rp ror --Jh - srLveyecl one riverbank apiece.<br />
The phase of lhe noon, color of the river and relative activi!y of<br />
aquatic olganisms such as prrwns and flsh, rere noted. Individual<br />
crocodiles were approached until l hey fled o! Here captured, and !heii<br />
size esrirn.r-d o -ordino ro o.F o evan clz6 a pqories {addpred f-on<br />
Messel, et a.I., 1981): Class 1 (< 0.5 n), class 2 (0.5 - 1.0 m). Class 3<br />
{> 1.0 - S 1-5 n). Class 4 (>1.5 S 2.0 n) , class 5 (> 2.0 - < 3.0 n),<br />
class 6 (> 3.0 n) and Class Eo ("eyes only,t or larqe indiwiduals, often<br />
exceedinq 3 n in lenqth, which submerge almost imediately upon being<br />
spotted (I,rebb and Messel, 1979). clocodiles conprising Class 1 and 2<br />
indiv-duals wcr- dp- rrecl - a' aver ro ib.6 wi h a dip net, rher<br />
measured (tota1 and snout-venL Iength), weighed, sexed and thei! stomach<br />
contents renoved by a nethod suqgesred by Taylor, et ar. (1978)f or by<br />
stomach pumping with uater fron a 250 n1 nalqene wash bottfe.Stomach<br />
contenEs were then preserved in 103 fornalin fo! subsequent<br />
i.lanriri.:r i.^ . .rF rl snr<br />
side of the .lo.sal neck scuLes (rosette) with a ye]low a se!ia1ly<br />
numbered floy tag 3 cn in fength. Salrnity and temperrture of the<br />
surface sater were measuled aith a Kahl scienrific ModeI Rs 5-3<br />
salinometer, and a numbered fluorescent marker was tied to the<br />
vegetation at the site uhele the crocodile was first seen. These narkers<br />
were collected the following norning, and their locations marked to an<br />
acculacy of approxinately 100 n onto a 1:50,000 map of rhe survey.<br />
RFSUI,fS<br />
Between June 1991 and ApriL 1992. salinities a! Kora Klias ranged<br />
from 0 -.. 10.2 o/oo and fxon \'1 .4 - 26.5 o/oo at Kuala Sinapokan (kn 37) .<br />
The rlver varied frorn a dark coffee coror during rainy intelvals ro<br />
qreenish blonn during dry weather. virtualLy no rain fe11 in the survey<br />
a.ea fron January - ApriI, 1992, and both salinity and remperature<br />
varied little. A toLal of 153 crocodiles from five size classes rere<br />
observed with a mean value of 10.9 t 8.0 sightings per survey. The<br />
hiqhesl number of clocodiles sighted occurred in January, 1992, durinq<br />
which 25 individuals wele counred in lhe survey area. None were seen in<br />
lhe \ovenbe,, qol surv6y. nLnerous in fecemoe.,<br />
1991 - February,1992, folloued by June - July, 1991 (Fiq. 2). Surveys in<br />
March and April, 1992 were hanpered by thick snoke from blrning heath<br />
and sc!'rb vegetation.<br />
<strong>Crocodile</strong>s of all size classes except class 2 were<br />
frequenlly in the lose! mangrove section of rhe rive!. more rhan 24 km<br />
do(nstrearn fron Kola Klias.<br />
151
t52<br />
1<br />
2<br />
3<br />
4<br />
5<br />
6<br />
7<br />
Tabfe 1<br />
size In)<br />
< 0.5<br />
> 0.5<br />
> 1.0<br />
> 1.5<br />
> 2.0<br />
> 3.0<br />
EO<br />
< 1-0<br />
< 1.5<br />
< 2.4<br />
< 3.0<br />
5.3<br />
12<br />
54<br />
9<br />
0<br />
0<br />
I<br />
!6<br />
d--i -<br />
20.5 t<br />
24.Q !<br />
Ir'1 .2)<br />
25.7 ! 9.3<br />
4',]<br />
36<br />
6<br />
0<br />
0<br />
0.6<br />
10.4<br />
1992.<br />
Based on a minimum nunJrer of 25 animals (seen on 1611/92), the<br />
esLimaled popularion of rh^
5062<br />
5499<br />
5492<br />
20 DEC<br />
2 9 JAN<br />
17 .tAN<br />
29 JAN<br />
29 JAN<br />
28 FEB<br />
9I<br />
92<br />
92<br />
92<br />
92<br />
92<br />
x-o<br />
23<br />
23<br />
28<br />
28<br />
32<br />
32<br />
5<br />
8<br />
0<br />
2<br />
TLlSV l.nl<br />
38/-<br />
4I.A/t9_1<br />
42.5 /24 .5<br />
42.1 /24 .5<br />
4t.r/19.3<br />
42.3/20_O<br />
rable 3. DaEa ro! r,o Ctdss I J rvenj.e .. porosus<br />
recaptuled belween Decenrber, r991 and<br />
January, 1992.<br />
100<br />
160<br />
140<br />
150<br />
Stomach contents consisred of prawns (A!yidae: Catjdina sp.)l<br />
ciabs (ocypodidae and Portunidae) and smaft fish (Hemiramphidae,<br />
Englaulidae and Elopidae) . Crabs (Ocypodidae) nade up the highesr<br />
frequency of pley ilens, while henilamphid fishes nade up rhe Iargesr<br />
volume of prey (Table 4). A sp.ider was founcr in one stonach. white<br />
numerous stomachs (11) conrained plant fibres. only one stomach was<br />
Ocypodidae<br />
(caridira sp. )<br />
Empty<br />
(No - srdnachs )<br />
13<br />
1<br />
5<br />
I<br />
\2<br />
3<br />
2<br />
L1<br />
l<br />
3_<br />
68.4<br />
5.3<br />
26.3<br />
5.3<br />
r0.5<br />
57.9<br />
5.3<br />
iza-1!t!e(nd) 3<br />
15. 5<br />
0.5<br />
4.5<br />
20.0<br />
2 .5<br />
5 .5<br />
160<br />
t?0<br />
L.1<br />
9.1<br />
1.1<br />
40.8<br />
5.1<br />
TI.2<br />
Table 4 Prey itens fion Class I and 2 crocodites by frequency of<br />
encounter (per stonach), ancl roraf votume and g<br />
DISCUSSfON<br />
s!uebing, et ar. (1990) found a slightly tarqe! poputation in rhe<br />
same area of the Kfias in 1987-88. The previous densiry estinate was 3.6<br />
kn -1 compared to the plesent 1.3 km -1. Conpared to tl. fo.*.. ,r.r.r,,<br />
the percentase of juvenite croco.iites (< 1.0 n) n:s increasea<br />
1.53
154<br />
substantially {839) in 1991-92 conpared !o 1987-88 (63t) ' ,thile the<br />
numbe! of EO sightingrs has decLined flon 12.63 to 10.4t. The estinates<br />
for the absofute populalion of class 1 aninals in 1991-92 nay, in facL,<br />
be lather too conselvatj.we. Based on a juvenile lecaPcule late of only<br />
12t, the popul.ation of juveniles alone could be lell ove! one hundied<br />
individuals (assuming that their behavio! was not seriously alreled by<br />
captu!e). Mark lecaptuie dala were unfo!tunately insufficienl for a nore<br />
reliable estimate to be made.<br />
The plolongred dry speLl affecting rhe west coast of Sabah since<br />
1989 (with a severe drough! during the filst four months of 1992) nay<br />
have been beneficial to the Klias crocodile populatlon, since floodinq<br />
of nests can be a najo! sour:ce of norlalily (Felguson, 1984; Magnusson,<br />
1982, I,iebb et al., 1983). Dry condj"tions can also inprove sulvey lesults<br />
(c. webb, pers.corun.), givinq hl9her population es!inales no!<br />
necessa!i1y !eflectlng a population inclease. Thus, the observed<br />
decrease in the estimated poputation since 1988-89 is likely !o reflect<br />
a leal decline.<br />
The absence of class 4 and 5 c, porosus in lhe Klias has been<br />
reported flon Australian rivers (MesseI and vollicek/ 1986; Messel and<br />
\r^-l:-cli loq?\ r.r
juwenires (T! < 38 cm and TL > ?0 cm), diffeling in aqe by abouts srx<br />
months. whether the larqe! juveniles remained near their oriqinal nest<br />
sites or not could not be assessed. rr is hoped rhar ,ith rhe<br />
contanuation of surveys in rhe larLe! half of 1992. anat the rnalking of<br />
more juveniles, that this question can be ansrered.<br />
The tocation of nesring acrivily in 1991-92 has evidenrly changed<br />
sirce 198?-88. Stuebing, er ai. (1990) found the greatest abundance of<br />
a]l juveniles (Classes l and 2) cenreled berween kn 9 - 19 downscrean<br />
from Kota Klias. By 1991 borh Ctasses apparenlty shifred aray flom kn 15<br />
an uppei nanglove habirat edged by Rrjzoplrara apiculata backed by a<br />
swampy plain. In 1991-92t C.Lass 1 aninals wele ctusteled in the tower<br />
Inanqrove/nipah zone? where they had been seen onty occasionalty in 199?_<br />
88. Furchermore, even lhough the 1991-92 nean fo! lhe locatio; of Class<br />
2 crocodiles vas nea! km 17.0, rhese ]arge! juvenites were atiscributed<br />
in lwo distinct subgroups cen!eied at kiloneters a2 -a.nd. 26 (Fiq.3). At<br />
least four nests piobably eristed in.ta!e 1991, three atong kn 24 - 31.<br />
one near km 37. The exisrence of a possibte fourrh is _imptieat by a<br />
cluster of class 2 animals flom kn 9 - 12, alrhough juvenites olcrer than<br />
a few months nay have already migraLed fron rhei! areas of origin. rn<br />
any case, virtually alI of the .est sites of 198?-88 had been abandoned<br />
by 19 91- 92 .<br />
the presen! incleased percenrase of juvenite C. porosus as de]l as<br />
their aI!ered distiibution coutd be related to a poaching inciclen! {hich<br />
occurled Marchi 19887 in t{hich 48 clocodites of valious sizes were<br />
either killed or removed from our survey alea. This incident rlad no<br />
obvious effect on the popularion in rhat year, since a foltor_up survey<br />
in Aprj-l, 1988 revealed compalab]e numbers of clocodites stilt present<br />
(Stuebing, et a-I.,1990) - In June-Jufy, 1989 however, the rive! was<br />
surveyed three rines, and only lwo crocodites seen. Numbers relu.Deo ro<br />
198? fewels by June, 1991, showing ao atmos! identical patte!n (conpaled<br />
to 1988) of juwenile abundance in January, 1992.<br />
Recaplure rate of juvenile crocodites (< 1 n) was nuch ress (12&)<br />
than that leported by Magnusson (21t), !hough Maqnusson incruated<br />
clocodiLes as large as 1.2 n io his sanpte. Slnce we obtained only 25<br />
juvenile C. porosus, conclusions regarding thei. ctiet are tentative at<br />
best. However, since infonnation of this kind is virtuatly nonexistent<br />
outside Austlalia. we have decided ro comenr on ir hele.<br />
In contlas! to the findings of Taylor (1979) in Aus!lalia, no<br />
insects or other insecr-like prey, aparr from a single spiate!, were<br />
found in rhe stomachs of juvenire c. porosus flon tht Ktia;. Atrhough<br />
the Austlalian aninal,s were taken from valied habirats, and were targe!<br />
(including animals up !o 1.2 nt), insects can be ploducts of seconoary<br />
digestion, and can be nis!akenty interpreted as sromach conLenLs<br />
{Jackson, et al.tl914). Taylor atso reported crabs as part of t'he diet<br />
of juvenile crocodites, an
156<br />
snapping wiLdly at plauns vashed uP on the ntud bank by the boq<br />
wave of the survey boat. The narked seasonalily and striking abundance<br />
of atyid plawns makes iL leasonable !r assume that reproduction in C<br />
porosus, aL leas! in Bolneo, could be influenced by lhe prawn cycle<br />
synchrony could be achieved via pho!operiodic cues, {hich though nuch<br />
leduced<br />
Class l<br />
near lhe equator, a!e probably stil'l detectable. Since Klias<br />
are already at ]easr 45 clays old (based on size; J.Jongr, pers<br />
conm.) when the prawns first appear. liming is ptobably nol mediated by<br />
nut!itional or olfac!ory cues associaled with Lhe prawns themselves.<br />
Another high frequency food iten, and a laxge porrion of the lotal<br />
volune of p!ey taken was the hemiranphid fish lprobabLy Dernogenys)<br />
known locally as "ikan jolong-jolonq", or halfbeaks. These are smalI (<<br />
100 m) surface feeders of the shallows comon to es!uarrne and manglove<br />
environmen!s. They are presenL throughout Lhe year' but night have peak<br />
..rrcr:ied with lhe only a single<br />
juvenile crocodile (5? of the lolal) was found tilh an enPty stomach A<br />
nuch highe! pe!centage (15.6') was !epoi!ed for Australian juveniles<br />
(Taylor, 19?9). rhe difference may have been caused by seasonal factors,<br />
since all of the K]ias juver,iles ercep! two wele collecced during Peak<br />
pley availabiliry, e. q.. Decenbe r-February .<br />
The three recaptuxed class<br />
than 300 n of their release point.<br />
1 tuve^aLes were found Hithin fess<br />
This observalion collefates with lhe<br />
finding from sulveys (Decenber 1991- March 1992), in which the<br />
distribution of Class 1 aninals along the river changed little until<br />
Aplil, 1992. 1n April/ mo!e small crocodiles aPPealed in the upper<br />
nanqrove area, and relarively ferer downsLrean/ as if they had begun to<br />
shift away florn theii nes! si!es. In northero Aus!ralia, the tendency or<br />
juvenile crocodiles less than six months o1d not Lo ]eave their initial<br />
capture point has been re9orted by Nagnusson (1979), who also observed<br />
the migration of small juvenite c. porosus upsrream fron nesting aleas.<br />
Based on linited information fron tHo recap!ured individuals, growth<br />
rales of KIias juveniles are slowe! Lhan rhose reporred fo! captive<br />
CONSERVATION<br />
Surveys in the Klias River since 198? have shown its population of<br />
' | 1a'p. ies seen<br />
between years nay reflect actual increases or decreases of crocodiles<br />
within rhe area. Diffelences be!dee. counts over several mon!hs,<br />
however, are probably caused by !he novements of the crocodiLes between<br />
the river and adjace.,L sdamp, a.d nrt necessaril.y by morLality. Since no<br />
comrielcial fishi.g cakes place, nor!ality in younqer aninals is probably<br />
) - rr-ir .<br />
pelhaps only once in several years. The appatent dtop in nunbers seen in<br />
1989 coutd not be quaniifaecl sioce the surveys were discontinued duling<br />
that period, bul lhe Iarge percentage of juvenifes seen in 1992 sugqests<br />
that the Losses of crocodiles were real, aod tha! the population is now<br />
The conselvation status of CracadylDs po.osus in Sabah (and rn<br />
Bolneo as a whole) remains in qdestion. wfiLakei (1q84) and Cox and<br />
Gonbek (1985), pain!ed a rathe! bleak picture of the state of Bornean<br />
5 years in d r ive, noLgn o -,-. -ocodi.es imply nat Crocodylus<br />
1- '; '! urbance<br />
....r i..a - d .'.1-1rva--:r." once in<br />
seve!dl yed!s', I-o4e\e , Lle :nsloious eLlccLs o perslstenr Pooching
should not be discounled. Habitat disturbance in !he forn of propose.l<br />
marine aquaculrure projecrs (in !he Ktias, at least) atso wili pose a<br />
se!io!s thxeat. Neverrheless, furrhe. conctusions concern.ing rhe plesen!<br />
and fulule slatus of Crocadylus porosus in Borneo shoutat be based on<br />
intensive survey !ork in specific areas, ideatly by Iocatty based<br />
scientrs!s and witdlife offi.e!s. Brief, extensive surveys, even by<br />
expexts, usually cannor provlde rhe type of assessment required fox lhe<br />
Prooer mdndgerFnc oI - he .!-c:es<br />
ACr(NOI.iI,FDGEMENTS<br />
We would like to rhank the Biology Departnent and Faculty of<br />
science and Na!urat Resources of !he Universiri Kebangsaan MaIaysia,<br />
sabah canpus for assisrance and supporr_ ne woutd also tike ro ihank M!.<br />
Mahedi Anclau/ DirecLor of the sabah DeparLment of ,iil.ttrte tor<br />
pernrssron ro ca.ry out rhis project. Financial suppor:r tor rnrs<br />
research \^'as supplied un.ler a gralr ffon rhe John D. anA Cartrerine r.<br />
MacArthur Foundation for which we are grarefut. ALso, we ntuch appreciaLe<br />
cne assrs!ance oi Lucv KirLsui, rwaDg Lariff Mohaned, Dulait cusiri,<br />
Handd Ahmad, Laqani Sahid, lisa yong, t"tilun paLek, Kasa Sah of UKM5, ancr<br />
Mr. Tan of KoLa Klias. Tha.ks :Lso rhe Sabah Medicat Dept., especiatly<br />
Suai.lin and Lenan for rany kindnesses. FinaLiy, M.. Lee iryanti, Shabdin<br />
Long and Shahrol Hamzah deserve speciat chanks to, ,"sc.ring our outboard<br />
engine fron the bortorn of a crocodile infesred xiver.<br />
Bayliss, P., c.,J.w. !'rebb, p.J. r.rhirehead, K. Dempsey and A. Snith, 19g6.<br />
Estimaring !he abundance of salrwater cro"oaires. Crocodytus<br />
porosus Schneider, in ridat we!tands of Lhe Northern Te!!.i!ory: a<br />
rna!k recapture experimenr to correct spottigh! coun!s to absolute<br />
nunbers. and rhe catibrarion of heticoprer and spor1igh! counrs.<br />
Austr. wildl. Res. 13:309-320<br />
Cox, J. and F. combek, 1985. A prelininary survey of Lhe croco.iite<br />
in Sarawak, East Malaysia. rUCN/!'WF project Repor! No.<br />
M^t 74/85, r'roird wildlife Fund Mataysia, xuara r,unpur.<br />
Ferguson, M.r{.J. 1984. rhe reproducrive biology and embryotogy ot tle<br />
clocodilians. In: rhe Eiotogy of the R€paitla, vol. 14; cans, C.<br />
and F.S. Bittet (Eds.), Acactemic press, r,ondon.<br />
Groonlclidge, B. (compiler), 198?. The rUCN Amphibia-Reptitia Red Dara<br />
Book, a con!ribuLion ro rhe Giobal Environmen! Mo;iroring sysrem,<br />
Part I. rntelnarionat U.j.on for rhe conservarion of Na!ur;, cland.<br />
Jenkins. R.tr.G. and M.A. and !.orbes, 1985. seasonal va!j-arion rn lhe<br />
abundance and dis!riburion of crocodytrs porosus in rhe tidat Eas!<br />
Alliqato! Rive!. Northern Ausrr:Lia_ In: The bioLoqy of Aus!ra_Laan<br />
flogs and lepriles, Gri9q, c., R. shine anA H,Ehnann tros.l.<br />
Royal zoological society of Ne, sourh riales, sydney.<br />
Kushfan/ J-A. and F.J.Mazorti, 1989. poputation bioloqy of lhe Anerican<br />
crocodile, J- tjetpetal . 23 lt) ,.j -21 .<br />
Kusuadi. S., 1985. A survey of rhe starus and ecotogy of the estuarine<br />
crocodile in seve!ar rivers in sabah and s;;aaak (in Matay) _<br />
Honors year rhesis, Deparrnent of Biotogy, Universi!i Kebanqsaan<br />
Malaysia. Sabah Canpus. Kora Kinabalu.<br />
Magnusson, w.E., 1979. Dispersat of hatchling crocodiles Craca.tyjus<br />
porosus (Reptilia, crocoditidae) . J. Herperot. !3:22-/_23:r.<br />
15',7
158<br />
Magnusson, w.E., 1980. Habitat required for nescing ot Crocodylus<br />
porosus (Reptilia, crocodiliCae) in Northe!n Aust!afia. Austr.<br />
wi]dl. Res. "t :I49-I55.<br />
Magnusson, !i.E., 1982. Mortality of eggs of the c!ocodite tCtocadyfus<br />
polosus) in NolLhern Australia. J. netpetal. 16:i21-130.<br />
Messe], H. and G.C. Vorlicek, 1986. PopuLation dynanics and the sLatus<br />
of Cracodyfus porosus in the tidal wate!ways of Nolthern<br />
Australia. Aus!r. r'rildl. Res. 13:71-111.<br />
Messef, H. and G.C. vorlicek, 198?. A population<br />
porosus j.n the t.ida1 watelways of Nolthern<br />
model fo!<br />
Australia:<br />
crocodylus<br />
Management<br />
inplications. In: trildlife nanagement: <strong>Crocodile</strong>s and alliqators,<br />
webb, G.J-, S.c. Manolis and P.J.trhitehead (Eds.). Surrey Beatly<br />
and sons Pty. L!d.in association silh lhe Conservation Comission<br />
o' Lhe NoLEnern ler riLo'y. Syon.y.<br />
Messel. 1,, G.C. Vorlicek. l,r.J, Greer an.l I.C. Onl"ey, 1981. Surveys of<br />
\F. ' ra..:. -alia anJ<br />
thei! crocodiLe populaLions. Monograph No.1: The Bly!h-Cade]l<br />
river systens study a.d Lhe .:,a!us of Crocodylus porosus in tidal<br />
waterways of Nor!hern Ausf ralia . Me!hods of for analysis and<br />
dynanics of a population of C. poro.sD.s.<br />
Stuebing, R., c. Isnail and K. Sallih, 1985. The ecoloqy of crococlile<br />
att.cks in Batanq Lupa!, Sarawak. Salarak Mus. J., 55: 189-214.<br />
Stuebing, R. G. rsmail and H.C. Lin9, 1990. The disLribution and<br />
abundance of the estuarine crocodile lCzocodylus porosDs<br />
Schneide!) in the Klias Pive!, 5abah. Paper presented a! the<br />
International conference on foresl bioloov and conselwatior in<br />
Borneo, Kola Kinabalu.<br />
raylor, ,J.A. 1979.The foods and feeding habits of subadult Crocody.tus<br />
porosus Schneider in llorthe!n Austlalia. Austr. wild]. Res.,<br />
6: 34?-359.<br />
Taylor. J.A., G.J.w. webb, and w.E. Magnusson, 1978. Methods of<br />
Crocodilidae) . J. Herpetol. 12 : 4r5-417.<br />
tlebb, G.J.W., 1985. Saltwa!er crocodile consetvation in !he Noithe!n<br />
Te!ri!ory. AusLr. Ndt. H's!., 21:458-461 .<br />
webb, G.J.w.and H. MesseI, 19?9. wariness in Crocodylus porosus<br />
(Reprilia: Crocodilidae). Austr. trildl. P'es. 6.227-234.<br />
webb, G.J.tr., G.C. Sack, R- Buckwo!th and S.C. Manol,is, 1983. An<br />
examination af croca.ly.L,s porosDs nesls in two Norlhern Australia<br />
Ireshwa er swanps, u;Lh on onolysis or embryo norLdli!.y. Austr.<br />
wiIdI. Res, 10:571-605.<br />
welfs, D.R., A.G.Maishal] and J.B. ],orry, 1975. A surwey of rhe proposed<br />
l(lias Nalional Park. soulhwest Sabah. world wil-d]ife Fund<br />
Malaysia, Kuafa Lunpur,<br />
Whitaker, R. and z. whiLaker, 1978 . A prelimanary survey of the<br />
saltwalet crocodile (Cracodylus porosus ) in the Andaman lslands-<br />
J. Bombay Nat. Hist.Soc,, 75:43-54.<br />
whilaker, R. 1984. A prelimina!y survey of the crocodiles in Sabah, East<br />
Malaysia. TUCN/!lWF ProjecL Jeporr no. 3127. wo!Icl wildl.Lfe Fund<br />
Mafaysia, Kuata Lumpu!.
AB S T RACT<br />
Aprit,<br />
A total of 14 spotfight surveys aere carried<br />
1992 along a 3? kn porlion of the Ktias<br />
out fron<br />
River in<br />
June. 1991 -<br />
nortnwesEern<br />
Sabah, Mafaysia. surveys were done a! 1ow ride berween 1900'- 0600 hls<br />
from a 4 m survey boat ar 15 km hr-1 by Lwo observers. A torat of 153<br />
sighrings wexe made, dhich varied berween 0 - 25 per survev {mean:10.9<br />
I 8.0 siqhtings/suivey). rwenty-five juvenite c!;codires<br />
"ere capturea,<br />
with thlee recaplules. Calculated densiry was 0.8 - 1.3 individuats kn_<br />
1, while the estinrated crocodile popularion nas 39.8 a 9.5 io! the<br />
survey area. Percentage sightings accordinq ro size class wele: Class 1<br />
(< 0.5 n): 4?t; class 2 (0.s - s 1.0 m): 369; ctass 3 (> 1.0 - 1.5 m):<br />
6t; Class 4 (> 1.5 S 2.0 n): 0g; Class 5 (> 2.0 < 3.0 m): 0gr Ctass 6 (><br />
3.0 n) : 0.69; Class 7 (Eyes Only): 10.4:. rhe snjaltest juwenites (class<br />
1) were found exclusiwely in !he tower manqrove/nipah secrions of rhe<br />
liver. appioximately 24 - 37 km dosnsrrean from the survey srar!ing<br />
point, and the mean their disrribution diiferecl siqnificanrfv fron cnaL<br />
of larger (class 2) juveniles (t-tes! for Dnpai!et sanpres, ;
:--<br />
3<br />
7<br />
6<br />
b<br />
6<br />
{<br />
F<br />
D<br />
2<br />
=<br />
,<br />
"l:<br />
'I:<br />
c)l<br />
II<br />
\\<br />
I<br />
\70<br />
3<br />
L<br />
D<br />
2<br />
F<br />
\<br />
D-O<br />
ct|n<br />
FD<br />
at<br />
ir<br />
=D<br />
alE<br />
agl<br />
\t ,<br />
o xE<br />
c<br />
-l<br />
-+- z<br />
I<br />
=
EI<br />
E<br />
a<br />
tr<br />
Class 3<br />
cl.sss ?(Eo)<br />
Jun Jul Aug Sept S€pl Oct<br />
Nov Dec Dec Dec J.n J.n Feb l.,ler Apr<br />
Survey montb *<br />
Ii$rre 2. I{um!e! oI sj.ghtirEr per montL 61ong the<br />
3? lm sr.rrvey area ol the Ic.ias River,<br />
Jurre 1991 - April, 1992.one Cl6ss 6(>3 m)<br />
crocoalile sas seen in October, 1991.<br />
*Additlontl<br />
survegs vere done in December<br />
(19, 20 & 30) 1991 ,rndJenu:rU l7 &29)1992<br />
to tmprov€ :5eessment ofctass 1 juvenjles
162<br />
w<br />
fft<br />
n<br />
Cl:ss 1<br />
Cllrs I<br />
Cl3rs 2<br />
cl:rs 7(€0)<br />
o 5 6 9 r?15 182l ?4 21 30 33 36 39<br />
Distance (km) domrstresm lrom Xota l1ies<br />
fj'gNre 3. nistribution oI crocodite sightj.r€s<br />
elonq 3? ln swvey area, I(Liss River.<br />
* A sjngle Clisr 6 ()3 m) crocodile v.5<br />
at km 23.
<strong>Crocodile</strong> Numb€rs on kke Karibq Zimbabwe and Factors<br />
Influencing TteE<br />
R.D. TAYLOR<br />
WWF Mdtispccics Project, P.O. Box 8437, Causeway,<br />
Harale, Zimbabwe<br />
Dj' BIAKE<br />
Natal Park Boar4 P.O. Box 127, St. Lucia Estuary 3936,<br />
South Africn<br />
atrd<br />
J}. LO1€RIDCE<br />
Departnent of Biological Sciences, University of Zmbabwe.<br />
P.O. Box MP 167, Harare, Zimbabw€<br />
163<br />
Niie crocod e (ergsqly!]! qijglisrs klreuti) populalions in lhe middle Zambezi river s)5tem have<br />
recovered over the past three decades from an earller hunting pressure. Although c.ocodile numbers<br />
have clearly increased at Kariba, Zimbabwc, curreDt udliTatiot regimes rely on sustainable harvesting<br />
of crocodile eggs frod the wild and from areas where there is also considerabl€ disturbarce ielated<br />
to ar iEshore gilhet fishery. There is a need, therefore, to provide quantitative evidence of preseDt<br />
popu.iatioo abuldance oq Lake Kariba and efforts to do so are described. Frtimales of relative<br />
abudarce usi.g sample courts from the air, and partiatly corrected for visibilily bias witi glourd<br />
counts (spotlight cou{s at night), provided a population estimate of 10 02O ! 2 306 (S.E.) for fte<br />
crocodile population aloDg the southem zimbabwean shorelioe of lhe lake, corresPonding to a de.sity<br />
of 5.0 crocodiles per lm. Tte r€sults obtained were cleatly inlluenced by th€ envirotrmetrtal coiditiols<br />
pertainhg at the time of the survels, with lake level appea-ring to be the most important factor<br />
idluencing coutrts. NuEbers were sigtrificatrtly higher in protected areas (Park and Wild Life l,and)<br />
compared with unFotected areas (Comrnunat l$d). This is la-rgely a reflection of crocodile<br />
disturbance ard Eortality rclatiDg to the giUne! fEbery. Errors and lirnitalions associated {,ith tho<br />
c€lsus t€chdques us€d are discussed in relation to mamgement ard modtoring ne€ds for r€latively<br />
simple, stardardizid indices of abundance to which estimates of precision can tE attached<br />
Introductiod<br />
The Nite crocodile population od the zatDbezi river prior to 1950 was probably relatively uldisturbe4<br />
and of unlaown size. siEilarlx the habitat also remained undisturbed until the dammiDg of the<br />
zambezi at Kariba gorge in 1958 led to the fo.mation of Lal€ Kariba along the cwembe trough of<br />
the middle Zambezi valey. In Soutb€rn Rhodesia (now zimbabe,e) prior to 1 1, crocodiles wero not<br />
classfied as game aninals, aad only the landholders permission was required to hunt then (Blal€,<br />
19?4). Durhg the 1950s crocodiles were heavilv exploited along the Zambezi, as elsewhere i! frica<br />
(Cott, 1 1). For example, one hunt€r shot 2 0m crocodiies on lhe Z3mbezi above the Vicroda FaIs<br />
during this tin€ (G.G. Hatl, pers. comm.). A number of crocodiles were also captured on the same<br />
stretch of river for liie export to (he U.S-A. (Macautay, 1960). The late Prol G. Boid (Pers. comD )<br />
was present when 29 crocodiles *ero shot in one night on tbe lrkola river, near Binga. He furthcr<br />
inform€d ooe of us (.IPL) that over 4 000 animals were shot by lwo teams of hunters on the middlc<br />
Zambezi in the rwo years before lale lturiba started fillins.
1,64<br />
It is probably safe to assume, thereforq that adult crocodile numbers on the Driddle Zambezi w€Ie<br />
low itr the early 196Os (Chil4 1944. ErEn in 1964, soodiles on kl(e Kariba were sti being shot<br />
by perso rel of th€ Department of National Park and Will Life Management (DNP&WLM)<br />
(Tlrodrso& 1972) because Lhey vr€re inte erbg with gilner fishing At rhe same time bowcvc!, a<br />
fledgling crocodile farming industry was being establish€d o[ l,ake Kariba on the initiative of a few<br />
pioneering itrdividuals (Blake, 19a; Chn4 1%7). This provided strong cons€rvation reasons for<br />
protecting wild crocodile populatiors bec.use the bult of stock held on crocodile farms was derilcd<br />
ftom eggs collected h the wild (Blake ad t veridgc, 195). Nercrtheless, there have been legirimate<br />
queries that continu€d egg collectioD (as w€ll as harcbling collectiotr in the initial few years) woutd lead<br />
to the de.line of the l.ake Kariba crocodile population add abandonment of tlrc for$er breeding<br />
gounds (Cott and Pooley, 1972).<br />
Furthermore, tittle is known of the adverse impacls ofbotl crocodiles and the inshore gillnet fishery<br />
on each other (Bourdillon, Cheater and Murphrce, 198t. Alrhowh mortaliry of c.ocodiles caught in<br />
fishing nets appears relatively low (Ke !uir, 1 ), there is littlc tolerance on the part of fishermeD<br />
towarals oocodiles because of the dam€e caBed to nets, often when crocodiles try to remove fish<br />
(Chimbuya and Hutton, 1988). Consequently nests and eggs are often destroyed wheD found (Hutron<br />
and Child, 1989).<br />
It was to address these concerDs and to provide a more reliable basis for the management and<br />
monitoring of the La-ke lQriba crocodile population rhat rhe preseot work was underlken. This<br />
involved the development of appropriate standardised survey and census t€chniques (Baylisi 198?;<br />
Graham, 1988) for estimating crocodile numbers. Use was made of sample couDts of adult crocodiles<br />
from the air, with partial correction factors derived usiDg spotlight counts at night Ground counts),<br />
made by boat along select€d lengths of shoreline.<br />
Study area<br />
The filling of l.a*e Kariba was complele by tq63. fo[owiog closure of lbe gorge ar Kariba in t958.<br />
Siluated ar 2O",|{) East - 29'3 Easr a 16"28 Soud - t8"6 Soulfi, rhe lake is orientaled south west -<br />
north east ovei a iength of some 3m km and covers a total area" comprising five mtural basinq of 5<br />
500 sq. km (Fi& 1). Its length along the southem Zimbabwean shorelirc is 2164 km. The lo$er<br />
eastem basins are characterised by a higbly denrlritic shoreline with a numb€r of large river estuaries<br />
whilst tow"rds the up['er western end of the lake, broketr billy couDtry of the Z^mb€zi escarpment<br />
borders the shoreline along much of its length. Consequently, crocodite distdbution as reflecled by<br />
nest sites (Fig. 1) is centred on the major ri\ers enteing lnke Karib4 with at l€ast 607, of nest sites<br />
occurriDg in the eastem basin between the Sengwa rfuer and Kariba itself (area A in Fig. 1).<br />
Whilst lnle Kariba itself is a recreational park within Parls and Wild Life Land, the only shoreline<br />
protected in respect of crocodil€s is some 3m km along the northern boundary of Matusadona<br />
National Park between the Sanlati ard Ume rivers. There is how€ver, a cohmercial iDshore fishiag<br />
conc€ssion bordering 30% of this Park shoreline (Fi&t). Inshore fishing els€where talcs ptace along<br />
much of the remahder of the shoreline witl artisanal fishermen livinq i{ Communal Land borderina<br />
the lake. Unlimired collecrion of crocodiie eggs preseorty latrcs ptace ;der DNp&WLM permit aloni<br />
the entire southem shoreline of the lake except for Matusadona National park. ell the major riveri<br />
which support crocodile breeding arc closed to public access from rhe lale durilg tie breediog sea.sor<br />
annualy b€tween 1 Septemb€r and 31 Dec€mber (Anon., 1991).
F 3 a aof<br />
?,-€i 5€j<br />
-i<br />
9(,<br />
a{t<br />
*il$Eq€ E<br />
5 *=rE ii;'!<br />
i,!ii+e3i<br />
E.=s€ 5f '-9<br />
E F E:i !E 1<br />
3ET;i=E€,<br />
z;:tt>;E<br />
tH€ii;*E:<br />
!-' -! S+a€ E+<br />
!?r;s gg s*<br />
i -: E.i ei: s<br />
;<br />
3<br />
CD<br />
=<br />
NJ<br />
6<br />
$<br />
-\'<br />
t<br />
L!<br />
3<br />
co<br />
E<br />
I\J<br />
s<br />
165<br />
.io
166<br />
Methods<br />
Surv€y desig!<br />
The southern shoreline of Lak€ lturiba was stratilied very broadly into a relatively high density stratum<br />
i.o the eastem basi! bet*een the Saryatr and Sengwa rivers wit-h a fifth somewhat lower deDsily<br />
stratuD comprising the remaining shorelhe to the west. The eutire shorelire was dividcd into 81<br />
sample uni6 (SU) demarc-ated by ph)sicil featur€s readily recogDizable from the air. The leqth of<br />
each SU varied f(om 4-48 lsn, dependirg on tlrc rature of tie shor€lire, with a mear leDgth of 17.2<br />
! r.05 km. withiq th€se SU, smaller sub-sample un\ represcntative of low, nedium a-od hig!<br />
crocodile density areas, were chos€n for spotligk counts madc by boat al night (Parker and WatsoD,<br />
19?0; Gralam, 1988). Surveys commenced in 19'8 ar.d lE79 along the shoreline of Matusadona<br />
Natioml Park. Itr 1982 ard 1983 repeated counts usiag sampliag Foc€dures covered sohe 407, of<br />
the southem shoreline in the eastern Kariba basir (Area A itr Fie" 1) and in 1985 the procedwe was<br />
e)cedded to the entfe shoreline of Lale Kariba withir zihbabwe. All coults *€re made in July,<br />
duriDg tle cool-dry winter period. At this timc of th€ year, visibility js edlanced as crocodiles sp€nd<br />
much time either oo the surface of the wat€r or basking on lar4 particularly during calE, su!!y da's.<br />
For each survey, prevailing weather conditions, water level, water and air teDp€ratures during dght<br />
counts and 24 h maximum and midmum temo€ratures were recorded,<br />
<strong>Crocodile</strong>s withia rardomly selected SU were counted f.orn the air using a high.ring Cassna 180<br />
aircraft. Flying height was maintained at about 50 n abov€ water level at speeds of 10G160 km/h.<br />
Suneys were flovn usually bet\reeb (Bh30 and 15h30, with a midday breat from 12h0G14h00. A<br />
oavigator-recorder noted all qocodrles seen by two fear seat ob'servers ard guarded against double<br />
counting. The tim€ lal€n to fly each sector *?s recorded and crocodrle numb€rs and distdbution<br />
plott€d oo a Eap of the suFey area.<br />
crourd counts<br />
It is recognised that a signific? propo*ioa of crocodiles remain uncounted from the air, especially<br />
animals lers $ar 2 m total lengtn (Gra.ha.g|, 1988). Counts of red/orango eye reflectioos from a<br />
spotlight at niglt car be used to reduce thrs soucr of error in accuracy. staDdardized night coults<br />
witbif sub-saople units were made from an opcn 5 Dr boat powercd by a 5 h.p. outboaid engtne. The<br />
crew consisted of an obB€rver in the bow ne* to. but ia froot of a recorder. and a driver in the stem,<br />
The obserr€r, using a had-held 12 v spotlight producing a narrow 30 watt beamJ countcd qocodil€s<br />
by sweepiry lie beam throrgh a 180 arc at thc surface of the water.<br />
The surv€y boat \vas operated about 30-50 m from, ard para.lel to the shoreline with occasronal us€<br />
b€bg made of a sEall 6 v headlahp for navigational purpoGes and to avoid subnerged and protrudi.g<br />
trees. A fairly colstant boat sp€rd of .1 km/h was mainhhed while seatching for crocodiles.<br />
Rellective Earters were us€d to demarcite th€ stan a.nd finish of saEpled sub-umts, lo enable their<br />
accurate plotting on charts ard subsequ€nt Deasuiement of distances covered.<br />
GrouBd counts w€r€ undertaken corcurreotly with the ae.ial surl€)s, during periods of litde or rc<br />
moor! usually tretwe l9h00 and 3h00. In order to minimise crew fatigue, survey tise dur;ng both<br />
aerial and trisht counts did Dot exceed 2-3 hours duration.
EstimatioD of abundance<br />
16'7<br />
The est;Dation of crocodile numbers follo*ed the expressio6 and procedure described by Joly (1 9a;<br />
1969b) aixd Parker and Watsotr (190). Assumiry that ground c.uds reflect an improved populatioa<br />
count, they may be applied to aerial counts to provide a pani.l estiEate of bias with \r'hich to adjust<br />
the aerial counr even thowh such application degades p.ecisiod (craham, 1988).<br />
An estimate of bias, R, is giv€D bla<br />
R=Ly/Lx=y/x<br />
whete x = the spotlight count of animals in subsa.aple udts aDd<br />
y = the aerial count in subsample coun(s.<br />
Counts x and y come from a $na[ subsample of udt$, bur even within t-bese, night couats cortred only<br />
a portion of tbc subsample udt. Co""equeltly, tbes€ counts, opress€d as density p€r km of shorelile<br />
were extrapolated to give x valu€s equivalent to the total length of the subsample unit and the<br />
coresponding y value.<br />
Tbe eslidate of X, the adjusted number of anihals ir rhe population, is giv btr<br />
\rhere N = the total numb€r of saldple units in lhe survey region<br />
y' = the obseFed number of animals in the nain saDplc urits<br />
n = the number of units in the subsample ]ll€d for the bias<br />
estimate<br />
nr = the n|,.Drber of ullits itr the main samole. and where<br />
j' -<br />
v'/ o'<br />
Where total counts were performed, N = d Jo[y (1 9a) provides expressions for the calculatiotr of<br />
statrdard errors applicable to the estimates of R and X. Estiffitiotr of abudallc€ in tfis x,ay is<br />
analagous to Jolys m€thod 1 which ideally requires equal-siz€d sample units but which can b€ applied<br />
to une{ual-siz€d sampl€ units. However, a higher varianc€ associated witi the estimate ca.n be<br />
€xpected. Error estimates are p.eserted as standard errors (S.E.).<br />
Results<br />
Population esdmates<br />
x = N.y/R<br />
Estimates of crocodile nu-mbers obtained in repeated counts a.long th€ same l€ngth of shorelioe in 1982<br />
atrd 1983 were compared using the varianc€ ratio t€st (Baile, 1959) and found to be not signific-antly<br />
diff€rent (d = 0.33). These estimates we.e Berg€d by *eighting them brersely to thc size of their<br />
variances (No(on-Griffilhs, 1978) so that the nerged estimate a.Drounred to 6 427 t 2 3o2 crocodiles<br />
(Table l). Tbe area sampl€d li€s in the eastem K-ariba basins between the Sanyati and Sengwa rivers<br />
and includes the protected Matusadooa National Park (Fig.l) and can generally be considered to<br />
support high crocodile densities, which amounted to 7.6 adldals pei k[| of shoretne from the.esults<br />
obtained.
168<br />
Table 1. PoBulation estimates of oocodiles in L3lc IGribE 1982 & 1983. The popularion esumale<br />
is X and its standard error, S.E<br />
Year Shoreline<br />
s.E. s.E.<br />
1982<br />
1983<br />
M6rged<br />
length (kn)<br />
7m<br />
850<br />
850<br />
7AB<br />
6 182<br />
64n<br />
2121<br />
13'0<br />
1 r51<br />
(%)<br />
Density<br />
(uo./km)<br />
In 1985 when the entire sourhern shoreliDe of LaLe Kariba ,xas samDled, ao estimat€ of 10 020 +<br />
2 306 *rs obtained equivaletrr ro a deDsiry of 5 crocodiles per km oi shoreliDe (Table 2). hdus;o<br />
of tie entir€ shoreline reducrd ortrall density slightl, but rct utrery€ct€dly, which suppons the idtial<br />
s&atificalion based oo nest concedtrations as indicat€d by egg collectio[s (Fig. l).<br />
Table 2. Poputation estirbat€ of crocodiles h Lale Kariba, 1985. The populariod estimare is i nld<br />
its standard error, S.E.<br />
Shoreline<br />
lenel! (kn)<br />
30<br />
22<br />
18<br />
s.E. s.E.<br />
Eo<br />
8.9<br />
7.6<br />
Density<br />
(no./to)<br />
1985 2Un 10 020 2 18<br />
5.0<br />
The aerial sampling fraction fo. the two earlier counts itr 1982 and 1983 exceeded 80%, borh rn terms<br />
of SU counted a length of shoreline sarnpled (Table 3). Th€ sub-smptiry intensiry of rle groutrd<br />
couots amoudted to 147a. In 1985, ceNus of the entire shoi€line reduced sampling iDtersity to 38%<br />
from the air and 9% oa tb€ ground.<br />
Table 3. Sampling inteDsity applied to count oocodiles h 1982, 1%3 & 1985.<br />
1982<br />
1983<br />
1985<br />
Total<br />
SU<br />
81<br />
Estimares of bias R<br />
No. E" Shor€line leagth<br />
Total Counted<br />
39<br />
31<br />
85<br />
91<br />
38<br />
79<br />
850<br />
2 000<br />
There ]'as an overall dowtrward bias in excess<br />
of 80% which was higbly significanr (p < 0.m1; Mann-<br />
Whitney U = 8; n = 19; Sieg€|, 1956). How€rer, €stimates of bias between ccnsuscs over rhe diff€rctrt<br />
years were trot significantly diJlerent from €ach other (Table 4) although a marghal de{line in bias<br />
rvas correlated with fal h lake level (r = - 0.96; P < 0.05; 1 d.f.; FE. 2).<br />
7A<br />
7&<br />
80<br />
86<br />
38
169<br />
Tabtc 4. Btimates of bias @; used to adlust aeriut o{ crocodil* on lrle Kariba tocether with<br />
stadard enors (S.8.) andconaspoad;ng lale "ouds levetr (m asl) for rhe ycar of survey. n = su$<br />
saspl€ siz€<br />
Year Bias i s.E. kIe IJ\€l<br />
t2<br />
1983<br />
1985<br />
o<br />
E<br />
6.<br />
.g<br />
c)<br />
o<br />
J<br />
/.85<br />
4E4<br />
1E2<br />
180<br />
0.135<br />
0.143<br />
0.151<br />
l. = 0,996<br />
p
1'70<br />
T6<br />
6 fi)<br />
(88 500<br />
t86<br />
01<br />
1.0<br />
(8t 100 c,<br />
-o<br />
E<br />
s Y t'8 2<br />
"9<br />
a,<br />
v (0<br />
J IBo<br />
l.? I 0<br />
19?8 1980 1982 1991 1906<br />
Ycar<br />
200<br />
-9<br />
6 o<br />
o<br />
()<br />
100<br />
F;g. 3. Total nurnbers ol crocodilcs (closcdcirclcs)<br />
countod in July along lhe shorclinc of<br />
Ma(usadona Na(ional Park betwcctr1978<br />
and 1985, togcthcr with corrcsponding lake levcls<br />
(opc" circlcs).<br />
'tatrle<br />
5. Crocodilc nnnrbcrs and lakc level irr Matusadona Nationol Park, 1978 -1985<br />
tna<br />
197)<br />
1982<br />
1983<br />
1985<br />
(Aorial)<br />
134<br />
ll8<br />
395<br />
3t8<br />
248<br />
Dcnsity (ground @unt)<br />
(no./km)<br />
i.rs<br />
8.89<br />
7.50<br />
5.9<br />
Lake level<br />
(m asl)<br />
486.87<br />
4a5.37<br />
4€4.26<br />
481.61<br />
479.58<br />
Water lcvcl is an important variablc aflcclhrg crocodilo coonls (Woodwa'd and Marion, 19ti; I{utotr<br />
and woolhousc, 1989) and appcars lo havc s(rongly iroucnced lhcse rq\ults. Thc lake lcvelwas stablc<br />
during lhc 1970s (Fig. 5) whcn thc first lwo survcys wcre undcrlaken. From 1981 onwards lake lcvcls<br />
bcgan to fau, beforo stabilizing again in tbc nrid-1980s. Prior to 1980 the littoral and shore zoncs of<br />
lhe lakc were charactcriscd by rxell developcd aquatic and scmi-aquatic macrophytes (Bowmrker,<br />
1973) wiih liltlc barc ot cxloscd substrate, cithcr abovc or bclow thc wa(cr. Such plant covcr would<br />
havc rcduced the visibility o[ crocodilcs. Frrthermorq lhc lakc levcl peakcd in J nc so that (hc<br />
amount ol cxpos€d subslra(c in J!ly, whcn col|nk wcre nade, was minirnal.
1',71<br />
By 1982, Lake Kariba had fallen nearly 3 n exposing considerable stretches o[ bare subslrare.<br />
Established beds of aquatic macrophltes were strandcd high above water lcvel and tbe rate of lale<br />
level rccession precluded the establishmeot of new plant cover. This situation persisted during 1983,<br />
c<br />
J<br />
'c i!<br />
g<br />
-o Eco<br />
E o<br />
()<br />
t00<br />
300<br />
?00<br />
100<br />
Crocodila denslty (no/km grourd counb)<br />
Fig- 4. The relationship belween crocodile densities cnlculated from gound counts and nudbers<br />
counted from th€ air.<br />
1i<br />
E."-<br />
(,<br />
-9<br />
_1<br />
I<br />
l<br />
| = 0.995<br />
p < 0.01<br />
Fig 5. Moathly lhcruations in l.*e levcl ar Krriba berwe€n 1978 and 1985. t-evcls correspond to ihe<br />
iQriba datuE (source: Zambezi River Aulhorily)
172<br />
altbough there w?s some develqpncnt of aquatic \,!gatatio.. While tle 1983 meatr estimate of<br />
crocodile dumbers was lower th"! tf,at of 1982 thc dificrcncc wa3 not signiEcant (s€€ above). Thc<br />
faling late level clearlyc anced vbibilig and asritortcs ofdocodile Dutrbcrs w€re consequently high<br />
(Table 5). Froo 1984 oni,ards, tlc late lc'/el bcgar to stabilis€ agai!, *hich was ac.oEpanied by the<br />
re-establish.B€nt of aquatic wgetation. This probably rcducci visibility ajrd contributed to a lo*,cred<br />
coutrt of crocodile numb€rs itr 1985.<br />
Protcctior a.rd iEhore gilhet fishiry<br />
Thc 1982 survey data wcre ls€d to €xamine ciocodib truebers ard d€nsity a.lodg prot€cted (National<br />
Park status) and unprotected lcbgths of shorelhe (Connunal laDd status), Egg collection for<br />
commeicial crocodilc rearing purpo6es tates place arruely in ths latter, *hich also supports an<br />
anisaml ilshore gill not fishery (Bourdilotr g tL 198t. By 1985 ro egg coUection had laken place<br />
h Matusadona Nationa.l Parl but therc i! a co--crcid fislilg codctssiod along some 86 lm of the<br />
northerD shorelirc of this Part (Fig, 1). Cooparirolrs could tbcrcfo.e be 6ade betw€en protrction<br />
and lon-protection as c,ell as bct*ten 6shed a|rd non 66bcd s€glrclts of th€ shorelirc. The dillelence<br />
in crocodile rumbers betv,/eer protected and noo prolect€d areas Ctable 6) was highly sigdificant (p<br />
< 0.001; X'1= 49.67 wit! 2 d.f.). The mean crocodile deDsitt itr thc conBercial fishiDg ?one of<br />
Matusadom National Park (approxidately 30% of the shoreline length) was 0.82 t 0.14 crocodiles<br />
per l(E coEpar€d to 1.91 t 030 over the rest of rbe shoreliDc, a dilference which was also significa.nt<br />
(P < 0.05: t = 269 with 14 d.t). Thc ov€ral density *as 150 ! 0.23 crocodiles D€r km of shorelin€.<br />
Table 6. Coaparison of crocodile numbcrs b€twccn protected and noa-prorected lengtbs of the Lale<br />
Kzriba shorolinc h July 1982. The prore.ted area is Marusadona Narioml park<br />
Obs€rv€d lumb€rs<br />
Shorelire length (km)<br />
Deasity (no./km)<br />
Discus.sioo<br />
Abutrdance<br />
Protect€d Nod Protccted Tota.ls<br />
395<br />
a2<br />
135<br />
4t3<br />
8A<br />
0€3<br />
808<br />
7m<br />
Geaera.lly, socadile counts tend to be very impr€cbe estiDates of population size atrd at best catr<br />
provide oaly a.D irdex of abundarc€ (Bayliss, 198?; Grabam, 1988) unless c.Dplicated, time-consurling<br />
and oftetr er.p€osir€ inrrstigation is urdertalen simultaneously (Hutton and Woolhouse, 1989).<br />
CoDventional surve's ale usually litrl€d to maDagemeot objectives which requile trend data with which<br />
to Eoditor chatrg€ ir abundaacc i[ relation to the managenredt treatme . That many crocodile<br />
$lrvels havc rot met tlis requireEent is well appreciated.<br />
The preseDt work provides tbe following.<br />
(i) Estima(es o{ abu$&nce for crocodiles on kke Kariba that werc previously not available. 'I'hese<br />
estimates are likely to t€ biased dox'nvards bccaus€ not all crocodiles ar€ s€en during ground counts<br />
od accout of both envilo iental facrors (Woodward and Mario4 1978) and visibility bias (Bay'iss,<br />
tg2
198?). Hutton and Woolhouse (1989) found the mean proportiotr of their study population counted<br />
from the gound to be 0.36, which, when applied to the Kariba estimate of 10 O20, provides ar<br />
adjusted estimate of , 833 crocodiles.<br />
(ii) Sample counts with estimates of pr€cision, and repeatability through standardization of tech$que,<br />
both of which are esseDtial requirements for monitorhg treods il1 abundance. Although mriaftes ate<br />
high, the very simitar estimates obtaired frorn repeated counts in 1982 and 1983 support the use of<br />
the Eethodolog/, at least as a monitoring procedure.<br />
t'l3<br />
(iii) A starting point from which to improve and refine app.oaches to mooitoring crocodile abundanc€<br />
on Lake Kariba. These should provide tread data which can be subiected to regression analysis, which<br />
is most usefully obtained from €stimates of relative abundance, either from the air or ground or both.<br />
cratran (1988) criticises th€ practice of adjusting aerial counts rdth a correction factor obtaided ftom<br />
ground counts, largely because precision is impaired by having to add the rtiances of the two counts.<br />
Nevertheless, th€ coosiderable bias evid€nt in the aerial counts $rggests such correclion has to be<br />
made, to at l€ast approach a realistic estimate. A total of 579 oocodiles was actually counted from<br />
tbe air duriDg the 1985 census yet th€re is a minimum of 800 females of breeding size on Kariba<br />
(DNP&WLM records). Practical considerations also suggest that on large water Mies (> 1m Lm<br />
shoreline tenglh) aerial c€nsus is the most cost-effective and efficient method of sure€y. It would be<br />
extremely tedious and lime-consuming to even sample count the entire Kariba shoreline using ground<br />
counts. Part of futue refinement, of course, should include better stratification which would improl€<br />
sampling efficienry.<br />
Crahan (1988) consid€rs nest effort a sup€rior measure of indexing crocoalile abundance compar€d<br />
to conventional counts but this approach has ,€t to be used at Kariba. The use of nest effort merits<br />
attention padcularly sitrce present unlimited egg collection would greatly facilitate its application, We<br />
would further sugg€st however, that nest effort and counts be used in tandem as complementary<br />
measwes of abundance, given the practical difficdties associated with both.<br />
Lake lcvel<br />
Whilst La-ke Kariba redained relatively stable during the 1970s with atr annual lluctuation of 2-3 m,<br />
tbs cyclical pattem was severely disrupted during the 1980s due to b€low average rainfall over much<br />
of the southem African sub-region. Rainfall in the Zamb€zi catchment det€rmines both the trend and<br />
annual amplitude in lake level. Thus inflow to the lake has reduced considerably and lake levels have<br />
steadily dropp€d (Fig.s). Fluctuations in lake lev€l greater than 3.5 m per atrtrum or 0.6 m pet month<br />
either de,stroy or retard establishcd hydrophytes whilst re-emergence of hydrophfes is fostered by<br />
Ilucluatio6le$s than 2m amplitude (Bowmaker, 1973). Large fluctuations cl€arly €nhance visibility,<br />
atrd hence counts of crocodiles. Converselt sma nuctuations will reduce both visibility and counts.<br />
Silcc rainfall is a stochastic variable, predictability of lake level from year to year will remaid<br />
utrcertain. This in tum wil affect the repeatability of crocodile countE at le3st until a sequence of<br />
Dormal rainfall years occurs. Such unce(ainty needs to be taken into ac.ou in the desig! of futue<br />
srrveys.<br />
Conllicts in resource use<br />
Mutual conllict exists between inshore fishing and both the conservation atrd utilizatio! of crocodrles<br />
on Lake IGriba. lrwered densities of crocodiles are appaient where fishitrg occurs compared with<br />
adjacent non-fish€d arcas. In economic terms the fisherynd the ctocodrlo indusfy aPp€ar
1',74<br />
coftparablc witb eachnrher {Chmbuya and Hutton, 1988). Although a progressive rural economic<br />
relorm<br />
.progamme,<br />
Campfire (Ma(in. 1986), which places much importance on wildlifc as a<br />
productive ecooomic base. is being irDplenented, wry few fisherman on the Kariba .takcshorc know<br />
tne varue ol a \^4td crocodilc. Whilsr this is cssentially an institutional problem, oui concern is that<br />
will undermhe the long<br />
::l]111IC. T"fU"<br />
term sustainabitity and hence econornic viabitity of the<br />
crocodrle Indusrry. It was an economic hconlive that provided lhe basis for ttre conseretion of<br />
crocodiles in the 1960s and unless such incentives now ajso rcach fishermen, the conservation of<br />
crocodiles on Lake Ikriba is potenrialty threatened.<br />
Acknowledgements<br />
Much of this work was undertaken whilst rwo of us (DKB and RDT) wcre emptoyed by rhe<br />
Department of National Parks & Witd LiIe Managemenr, Zmbabwe anrl is pubtisUeA witt t_he<br />
Dire{tois prrmission. L-ogisric, supporr for the 198j survey was pa(ly funded by thc University of<br />
zrmoaowe lcsearch Eoard. Numerous colteagues assisted wirh the physically dcnanding task of<br />
coun_ting crocodiles from the air along a torturous shoreline and we arc especiaily grateful to Rupert<br />
and Malcoln van der Riet for rheir skilfut piloring of rhe aircrafr.<br />
References<br />
Anon., _(1991). Parks & Wild Life (Hunting of Cncodiles and Removal of <strong>Crocodile</strong>,s Eggs) Norice,<br />
191. Stalutory<br />
Insrrument No. 7 of 1991. covernment of Zimbabwe, Harare.<br />
Bailey, N.TJ. (1959). Staristic"l Mcthods in Biolog. English Universiries press, London.<br />
Bayliss, P. (1987). Survey merhods and monitoringwithin crocodile managcment programmcs. Vild!&<br />
Maqagess!]!_<br />
_ _ : CJocodiles a!!! Allisators. (Eds.) c.J.W. Webb, S.a. Manolis a p:. Wtr;rehead,<br />
pp. 157-175. S. Beatty & Sons, Austratia.<br />
Blale, D.K._(1974). The rearing of crocodiles for commercial and conseryation purposes in Rhodesia.<br />
Rhodesia Science NE!! 8, 311-314.<br />
Blake, D.K anq higridCg, J.P. (1975). The rote of commerciat crocodile farming in crocodile<br />
coiservation. Bioloqical Cor'ser.?lion B, 1-z72<br />
Bourdi or\ M.F.C., Cheater, A.p. and Murphree, M.w. (1935). Srudies of Fishing on tnke Kariba.<br />
Mambo Ocaasional Papers, Socio-Economic Series tto. zO. l,tamU fr-s"Earare,<br />
Bo*maker, A.P. (19?3). Hydrophtte dynamics in Mwedda Bay, Iake Kariba. Kariba Studies 3,42_59.<br />
Trustees of the National Museums and Monuments of Rhodesia.<br />
Child, G.F.T- (1987). The management ofcrocodites in Zimbabwe. Witdlife Management: Crocodites<br />
atrd AlligatoT. @ds.) c.J.w, webb, S.C. Manolis and t:. Wtrirehead,lpllo4z s. neany &<br />
Sons, Austlalia.<br />
Chimbuya,.S. and Hutton, J.M. (1988). The conflict between crocodites and inshore fishing on Lat€<br />
Kariba.<br />
ryggsdilgs<br />
of the SADCC workshoo or Crocodilc Manaeement and U-tilization.<br />
Kariba, Zimbabwe. 2-6 June 1987.
Cott, H.B. (1%1). Scientific rosults of aD enquiry into the ecology and economic status of the Nile<br />
crocod e (qg!or!!Its niloticus) in Ugarda ard Northern Rhodesra. Transactions of the<br />
Zooloqical SQgieltf q! lrndon 29, 211-356.<br />
Cott, H.B. and Pooley, A.C. (1972). Ibe {3tlD eI crocodiles !s A&!!3. IUCN publ. (N.S.) Suppl. Pap.<br />
No. 33, 1-98. IUCN, Gland.<br />
Games, I. (1990). The feeding ecolo$' of two Nile crocodile populations in the Zambezi valley. D.Phil.<br />
thesis, University of Zimbabwe.<br />
craharn, A. (1968). The l-ake Rudolf crocodile (Crocodvlus niloticus Laurenti) population. Report to<br />
Kenya Game Department, Nairobi. 145 pp.<br />
cralam, A. (1988). Methods of surveying ad monitoring crocodiles. Proceedines a! tre SADCC<br />
workshop g! crocodile Manaeemedt ald Utilization. Kariba, Zimbabwe. 2-6 June 1987.<br />
1'75<br />
Hutton, J.M. and Child, G.F.T. (1989). <strong>Crocodile</strong> managemenl in Zimbabwe. <strong>Crocodile</strong>s - Their<br />
Ecology, Management aad Conservation. IUCN publ. (N.S.) pp. 62-79. Gland.<br />
Hutton, J.M. and Woolhouse, M.EJ. (1989). Mark-rccapture to assess factors affecting tbo p.oportion'<br />
of a Nile crocodil€ population seen during spotlight counts at Ng€zi, Zimbabw€, and the use<br />
of spotlight counts to monitor crocodile abundanc€. JqEa! q[ Apolied Ecoloqv 25, 381-395.<br />
Jolly, c.M. (1%9a). sampling nethods for aerial census of wildlife populations. East African<br />
AEicultural ald Forestrv Journal 34, .16-49.<br />
Jo y, c.M. (1%9b). The treatment of errors in aedal counts of wildlife populations. Eas! African<br />
Agicultuml g!l! Forestfl Joumal 34, 50-55.<br />
Kenmuir, D. (198). A wilderness ealled {a!iba. Wilderness Publications, Salisbury.<br />
Macaulay, R. (1960). erceodilg Trader. The Adventurers club, lrndon.<br />
Martin, R.B. (1986). Communal Areas Management Programme For Indigenous Resourc€s<br />
(CAMPFIRE). Unpubl. Report, Branch of Terrestrial Ecology, DNP&WLM, Hara.e.<br />
Norton-criffiths, M. (1978). Coultinq Animals. Handbook No. 1. Handbooks on techniques cunently<br />
used in African wildlife ecolog. (Ed.) JJ.R. crimsdell. African Mldlife kadership<br />
Foundatio& Na;obi.<br />
Parker, I.S,C. and Watson, R.M. (r90). <strong>Crocodile</strong> distribution and status in the major waters of<br />
western ard central Uganda in 19,69. Eqs! Alrirlg Wildlife Joumal 8, 85-103.<br />
Sieg€I, S. (1956). Non-parametric Statistics &! the Behavioural Ssletee!. Mccraw-Hill, New York.<br />
Thonson, w.R. (1q72). A field guide for estimating the overall length of tho crocodile. lg!!ga! e! &Q<br />
Southern African wildlife Manaeement l\segbfe! 2, 27.<br />
Woodward, A.R. and Ma.ion, W.R. (1978). An evaluation of the factors affecting night-light counts<br />
of alligators. EIgsEEIlilgs of the southeastern Association of Ebh aagl !U!!U!fg Aeencies 32,<br />
291-T2.
l't6<br />
Ultrasound I Evaluation ol the Fotlicle Developm€nt in Adult Femde<br />
Broad-nosed Caiman (Caiman lati rostris)<br />
Miriam H. Vac. L.M. Verdade:. C F. Meirelles. R.E. Larsen. F. Michelotti.<br />
M.C Ranget. C Z Salem & .A.. Lavorenti<br />
CIZBAS / ESALQ<br />
University ot Sdo Pa'rlo<br />
Caixa Postal O9<br />
Piracicaba 134OO 5P BRAZIL<br />
1 Ulhasound machine: Aloka No. 210 - DXZ t3.F Mhrl<br />
? Authol to +vhom<br />
correspondence<br />
should be sent
L77<br />
Ultrcroundl cvrlultaon ot tho lollicle dcvalopmcnt in adulr lcmalc broad'<br />
nosed caimans lCaiman.lElitoslthl<br />
Miriam H. Vac. L.M. Verdadc?. C.F. Mchc$as. Ft.E. Lllsen. F. Michclotti. M.C.<br />
Flangcl. C.Z- Salem & A. Lovorcnti<br />
CTZBAS / ESALQ / Universi$ ol 56o Paulo<br />
Cx. P.09 Pkacicaba 13400 SP SRAZIL<br />
I ntroduction<br />
The reptoductive cycle of crocodilians has been shown to bc more complex<br />
and evolved than that of other reptiles. Their sexual matutity is size and age<br />
dependent. and normally- malcs grow up fastet and g€t largcr than lemales whan<br />
adults. Generally. caimans. alligatots and smallcrocodiles reach iexual mahnity at<br />
a relativcly smaller size than gha als and the lalgcr crocodilcs [Mcgnusson ct al'.<br />
19891. According to these authors the r€ptoduetive clEb ol crocodlians can ba<br />
distdbuted all ycar lonq. like faioln eigqqdihrt Ellcqdi[u in $-|E Amazon bashi<br />
in two distinct Feriods. like Nilc crocodile h Uganda and Kcnya wharc some<br />
lcmales nest in August 6nd othcrs in Dcc"mbcl; or iust in a rcstrictcd pctiod of thc<br />
year. like the other species.<br />
The Arne can alligator. which occupies the North limits d dl crocodilbns<br />
distribution. has ! vEry delimitcd rtploductive cyclc. lt stltts h Malch with the<br />
beginning of gonadal dcvclopment through hormonal aclion. whcn Eit arid wrttl<br />
temperature rises. Copulation occuts from lateAprilto ea y May. ?Yith the egglaying<br />
peak occu irtq in a two week period inJunc [hot ycarsJ orJuly (cold yearsl.<br />
Eccording to Jorhan & McNeasa [1979J. Tharc is a rapid &cline of tha adult<br />
female ovaries and adult malc tasticles soon after eggiaying and duing thc<br />
incubation pe od [Lance. 1989).<br />
I (Ita.ound mtctrin.: Alokr No. 21OO)
178<br />
There ir too little iniorrrration on the broad-nosed caiman reFroductive cycle.<br />
The first captive breedinq result. may elu*idaie some important aspects such as:<br />
nestinq. incubalion and hatching Feriod- clutch ei:e- etc. f,rerdade et a1..19321.<br />
However. Er.3zilian captirre colonies of the lFecies har.e a lor.v level of hatching<br />
success possibly due tB rnanagernenl mistalies ,3nd,ror high eninrals infertility rate<br />
perdede & 5antiago. 19521 The folla,.+ing factors.dn nlfect the snimals fertilitv:<br />
genetica. age [si:e], illnesses. and niarra1:ternerrt practices such as. sF8 ratia.<br />
stocking density, breeding pen de;ign. ,.tress- and feed m6nngen-'ent<br />
[L:ardeilhdc.<br />
1 SS9l.<br />
Ultrasound erral"ration of tl're fullicle de'reloprr'ient may indicate the st.ge of a<br />
female in e certain moment of its repraductive cycle. lt can also be used to<br />
evolu€te the inlluence c,f erogenous hormones ond the possible correct time t'l the<br />
,rrtificial insemindtiar' as described by Lersen et al. [19S8].<br />
Materials & Methods<br />
We evdluated the follicle develooment of 1l adult females lrorrr November<br />
l9g0 to January 'l 991 . and of three adult fernales hom Augusl 1 331 to January<br />
1992. We tested bath '..entrtsl and l€teral aFpro.rches '/+iih the rdt.aeound<br />
transducer.<br />
PMSG ,ruas tested to induce ,rvulation in five females, The mean dose of<br />
'17.53<br />
lu/kq ranqing from 13.43 tD 20.0O lU/kq was di\.ided into sir! or seven<br />
applications lrom early November through the middle of Becember or Januor_t'.<br />
Flesults & Discussion<br />
t<br />
BEth ventral and lateral ultrasound transducer approaches rlrorked well in<br />
medium fernales ismaller than 90 - 95 cm in sncrut-vent lenght) but the lateral<br />
approach worked better in larger ones because of the osteoderms c'f the belly skin.
119<br />
During the first leal lust t'.+r, lemales leid eggs and arrother one ovulated but<br />
did not lay eggs. The othets showed a sholt develrpment followed by a tegtesstcrn<br />
of the follicles.<br />
Duting the second period iust one female ovulated and laid eggs. InAugust<br />
the lemales had follicles of 1.0 to 1.5 cm diameter, arrd ovulation occulred about<br />
'14<br />
weeks latet, when the follicles reached 3.0 to 3-B cm diarrreter [Figures 1 and<br />
21.<br />
The tested PMSG doses did not produce follicular development with<br />
ovulation [Figure 3]. Three possible teasons ate:<br />
At The dose of FMSG was insufficietrt to induce ovul.:tion:<br />
E] PMSG was used l€tel than ihe best period for its action. SeFtertrbel -<br />
Dctober mdl be bettel than No'/erBber " DecemFer.:<br />
Cl Periodic handling lor administration of drugs could have produced a level<br />
of stress incomDatible with nolmdl ovarian lesponse t.r exogenous hormones.<br />
Female reproductive activity occurred over a much btoader time Period thart<br />
observed in the alligator. \,vell-developed shelled eggs. ovulating eggs' and<br />
enlerging ovarian ova +!ete EbselVed during the sarrre day in difletent females<br />
within the colony. This may make it more dilficult lor 'l regimen of hormorrdl<br />
stimulation to produce synchrotrised ovulation in capti'/e colonies<br />
Acknowledgements:<br />
Fundo Mundial oara a Natuteea " \.aA{F, Pt':'cesr No. 664D"03?.<br />
FundagSo de Ampato i Pesquisa no Estado de 56o Paulo-FAPESF.<br />
Process No. 50/2832-0<br />
Institulo de Pesquisas e Estudos Flotestais'IPEF<br />
Fundag6o de Estudos AgI6lios "Luiz de Queiroz" ' FEALQ
Litarsture Cited<br />
Cardoflhac. P. 1989. Husbandy and prev€ntaliva medicine practicac th€t inctease<br />
reproductive cfliciency of breeding colonies of a$igators. Aqurcultula Mnlket<br />
Development Aid Program. Flodda Depa ment of Ag culture and Consumer<br />
Services. Tallahasse. Florida. 25 p.<br />
Joanen. T. & McNcasa. L. 1379. Time of cgg deposition for thc American alligotor.<br />
Proc. Ann. Conf. 5.E- Assoe. Fish & Wildl. Agencies 33:15-19.<br />
Lance. V. | 989. Fteprod,rctivc cycle of the Amcrican alligator. Amer. Zool.<br />
29[3J: 999-1 01 8.<br />
Larsen, Fl.E.; Cardeilhac. P. & Godwin- F. 1988. Atilicialinsemination in the<br />
Amcrban alligato. Proc. Ann. Mcct. Soc. Thciogcnoloqy- Orlando. p. 285-292.<br />
Magnusson. WE.; Vliet. K.A.: Pooley. A.C. & Whitaker. Fl. 1989. Flep*oduelion p.<br />
118-135. ln: Floss, C.A. [Ed.]. Crocoddes and alligators. Eoldem Press. Sdverwaler.<br />
Aushalir. 240 p.<br />
Verdade. L.M. & Santiago. M.E. lgt|2. Status of captive population of broad-nosed<br />
caiman lCaiman !1ig]1igl in Brazil. Proc. Xl Wolk. Mcet. Croc. Spec. <strong>Group</strong>.<br />
IUCN ' Tha worH Con*crvation Unbr. 2 - 7 A€ust 1992. victoria Falls,<br />
Zimbabwe-<br />
: Lavorcnti. A.; Michelotti. F; Flangel. M.C. & Cullen. L. 1992.<br />
Captiv. bleedng of hoadnoscd caiman [CliE{<br />
lati]ortrid in 55o Par,rlo. Btazil.<br />
1992. Proc. }(| Wo&. Maet. C.oc. Spec. <strong>Group</strong>. IUCN - The Wodd Cs$effdtion<br />
Union 2 - 7 Ar,rgust 1 St|2, Mctoda Falh. Zimbabwe.
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184<br />
F,i]p!..lt,Ar IaN i l-'ftri o' t!-{E gFt:IA-L=D<br />
II{ IHg !.]F|JEZUELAN FLAIN<br />
VELAZCO, A. (*) anci J. AYa\ZAUi.JENA<br />
.]AIIlAN<br />
* Servi€io AL{tc,nomo PROFAUNAT Hdf. Camejt}; OeltLe, m(r.:;rr.rr|]iir(,<br />
Cara€as 1010 Ven€,ir: Ltf- I a<br />
"<br />
IntroduEtion<br />
Sin{:r: lrrirlll, f trn r:fifimf,)rni,ir.l !,rf-,irtl,_rl:i.lrrr r:il f il.:: r-L.rr LFr<br />
tr.rha (liI(nr l:.'iIlfl(l rr j.rnar] '<br />
[B_r_1]!:,1, 'rri r'r,,!l: 1', h,i:: be.:+rr ':1i;vi',1r]<br />
irr..r ,rt: I .,Ir!i,.<br />
Th,:l 1,!!r{ I j r!, t,11. I pi: r- lr.iI : N:ir , 1 ,<br />
$f {r ,rririf:frlJ rrIfr'l:r:,]<br />
' J_rr,rw<br />
'<br />
,,. , i. ,<br />
i:intv ;,,r. i ;:,. l. : ,,,r 'il,i, , i,:., l'<br />
'rh.rf' 1.fli.i iri. i,. ,ii i, ,, +rfr', .,r',, ii] !, rl<br />
]t ;.i:, fir.t ;.t:l rirr" L f:r :ri lr , I '.i,<br />
IV uri lf ir , ,ir,:,r.<br />
i,<br />
I rrr.<br />
, r-q(i i.;,tr(i l,i.i! i-! I rtrrjr |rl<br />
,ri 1.! a,l<br />
: i;ir,' . :ii:r l ,i r'i , i l'il<br />
r,j i:,;trrr r irr:rt i rr- 1r t:rr i: r.r ii !i, i: : r j<br />
']]/gi]lr]]if'|l|;,];.;.:,.'.il;]l]1,'<br />
rriii)rr-nl lji! llll]l|i ,:,. r:,!,ri i,,, .r,, I irL l. l..rii<br />
'i: :i<br />
" , ii:"1':|rl lr<br />
I t. ,,r I : :r,r : ;,1::r rr,i. ., f,,,.,i t rLi,.r't,ri |i,:"i1jrt..<br />
,i , L ,/ , i<br />
i,.:jL.<br />
lrl ,.<br />
rl ,r,!il<br />
'.,<br />
lrl I<br />
i'',.: r,:i<br />
f:i Iir,i.,l.<br />
ri, j; ii.r.l ,.i irr,.r<br />
..r.:.r lrf'!-'r':jlri: lrJ<br />
" i ir:i;rli<br />
ir,i,; :;llrii': i!i,, ;1.<br />
rl,i ii.;::, i , r,:f ..: :lt:Lrr 1..,1 :"r I : .tirL.!i,,,r, .iiitr,:::!
HatFrials a.ld HethodotEqY<br />
f'liLlhtI/ r €:fl!,'i.rti tn{rf:<br />
qonsllc:i-r Li!'fi yder:!: il Fr:l<br />
185<br />
1ac:e dLrr:rnrl tfr€e rJry !ru.r!i.r$.r'1 r!.rtr<br />
1 tr Ay 1r?91 anrj j anlrar'/ 1i'| :lr.lci'<br />
lii, ,:1,i,,,i;11:i1r' ,:t!::rll!,ri li, ia":,r: rtturr:i.trn iry $ai,t,r.'' rta<br />
i,irrng riLrrr.rrq Ilrilhl.I; f:rlfiiit,r$' ih!. ";inr: li^il-i-!!Fl rlr i:r '!ii,.<br />
il;r! iritrrl nirJhl, A' r:i]rrl:,iii: r.r itr]l:l |",;1,.;'i d'i'iit:rj.he.J f,-v<br />
.1,ri,:t !'=ri:. I Ir?ll:li)<br />
"<br />
r_iy.rr<br />
Results<br />
6lrarico Reg ion<br />
i.r:' frrr|liiirr:rl ,' -.-, .:i:'rlillf r,liiii, /iri:l ,il:l :l;r! |]r: fri ]!.:ii 6!r,:;lrli:<br />
ii.:.].rr..]ll|i,.:'.']:i"'r|:]i[l1I+1]pi-esfl',r]|E':]"l'|].!;1|r.iii:iri1!'Ilii1r,.]r.<br />
ri,:,:,! tt,i<br />
fr r<br />
.r .r1: !r:rj,!i r'{Hir,: r':riifi'llllrl {'i ir r'.,ri i ,l<br />
-<br />
r;rIj 'ri,,,.:r illill.:!!1r- ll.. {; l'art \ir 1:<br />
ii'r(:r {iri.j;,r ::il:irri t!!, F .ri ,rlr,ri i i/rl .":' ':i r, ':i lj'- ir,.l<br />
lrri: ,rl,a$,r, L.l .:;:lr lrir\' r' :r:l i:,;1r, i: :lir,ri"r IIt iii 4 i' r:)i; Lr+<br />
i | 1 , I i !/ i ' I i I ir I ,,t fi(1in lllsq1 r: \.' r.:.''ii:rt1"r_y. l_rii{ !,i;iq- ii 'l_'r,rr"!r, lL?:l r,i<br />
l:]t.i\irc:irl.r j];lr;rt){.! ,..,l ,t; 'i ir!1i:i. ,:r:ri:r:lerii(?ci lri!!r,,lar:1,r,'l<br />
':,,i Er l, ,,' L<br />
Lower AFLrre Reqianr<br />
t,i i i lr<br />
'-,ii ii:rir r,_. r,i: 1]i;l.r<br />
l I1r ,i i :i , r:11::<br />
i trfl i v ., i:,,,,.l q.,:<br />
j ;r! e4.<br />
_/fi,1/:l<br />
lr.r i'!F:v Lr r.,i:t rii'.?:.|<br />
;,\:;ilr r',1 :,rl ,jf .n"1! :1,:i,l-'7:r ':t]1? l-,r'rlr:(l {::ri{inrr,t HPi'r-)<br />
.<br />
1.i<br />
tllr:i; l;<br />
i i ir$.l<br />
{r:i /i:rs.<br />
lrll] :;l I<br />
.! rr!!1 ji:rnirl! il-ri'rir',' r}i il :rir)<br />
lr:t: r,i : rr l, ':. ;ri,, i'ii! iiii :i!Lr|*r r:i,r-rr'.: l irii.rl,lre: Fllll il:!nd {:11,'i" L<br />
l.l{l .:i I linr'l,! r! !., i r:, t i l t . i. , i i '' !:h.!irr.,, ,.ri.trlr &?"::i .tl irrfl:ivli:irrill: lrr,rii<br />
tT r-,3r n,ii r, l:lrf ti'/<br />
fron i li:t:. l{I .'irir 1llli,:jil L::i:<br />
for i idr.: l: ': lr:1li' l"i':': .r{ ': lr,'rFnr l:, ri:vl)ri1:,11 l{<br />
fi :ir!,:" .:,i!.;\h!l.] ,lr)1tJ].i.i:i tal:ir:)Lr f I'i::1.':i: fr! vo {r_iiF:r.<br />
Hiqh ApurP Req ton r<br />
!i'i:' f'lri..i1r lli)r!r€i hl.'lii rl t:r(:rlrFr i riir'lii i"l ' j..1,1:' lilrid rri, 'r'l<br />
"r'r'i- I<br />
:rrill;r,'?lii: :'.:t r;r::rl-! |:l]!r1i]ai{l! ilrr a !','rl4:{ flF tfi i:.': I ,:--ir'riiiiiJ ,;1t , '"<br />
i:i!,tlrilrlrifin t a-il?.4r?!l :i.!]{ jivirltt,ilL':' titr!'! er::il.].fllii lr!:ri ]:rJi- 1l},:il:;i<br />
i rdi."i.*ri,ni:i, I)!rr hi! dr'lrlij:i Lt fr.v l-hl+ rrjllliorr i llar lr fi-r-' :ll . liiil<br />
$.i;e ,:ilr/r.r{: i:rrr'{: Ancl hief.lrqr*irr (f:lr.rrt" Nl? 2 rrrii +:l1rrrr:' N1 ?J nre<br />
.._. j lni-:lr! r tcr f ho!;e IE,prr'[r,'cl h/' A!,rr;:":!Jlitrr!.:r (1q$j) Rnd :]t:;ja1!<br />
.: lQili'l., rh,-rr,r( l+:r:i.:.r,rl hy |rL ij,'r .rm-i.r1a:l qhnirF:,
186<br />
Southern Apure Reqion:<br />
I t cor,rrrtses<br />
r.:6:..)7e l;' ra"-J -r.,* ,n*',,;i.1, ';;r;' :t i".,.\ .,r,,)<br />
.,n*sr :;q.r:z<br />
"1""t"rtro/r l:rirr: !rr1' r-rnrn rr)ii lat*r<br />
equivalflnt- o". tha?<br />
t,, rs.s=2<br />
{:r+riciLr!i'<br />
,,+'ti.l"T:-jo<br />
t'riri(h -ie<br />
o+ thr:: reqicjnAl t"t-*r, ;ri.'i^jl'i'a.rrn/Jer FhF l'rn'j.ou- rnrl 7,1i:'t<br />
rFsion;r a""*itv,,i"r,. ri' ;;;:'";;.1.]il,ll:J,,1 ;,,i::;,i:j,,,1,:,, "<br />
The .iize<br />
.<br />
s Ir_Lrc +-Ltr_H inrj, h:st{]qrcr}<br />
snipe wrth<br />
:ihi:l4 the<br />
a grf!;itEr<br />
pyramjddrl<br />
I,rc liirrr<br />
'ch.rrL<br />
ri r+ i:.tits-:<br />
N!.1.1<br />
.<br />
inrt r<br />
t,rriii: II<br />
iqlrr I.<br />
tnjrv:.rtLrate<br />
Ncr- ",\<br />
lloody Plains Region I<br />
thF r€rgj.trn {::c}ver.ri tlfl<br />
cover!.:rl 19::..A7A fia t:.,lx\<br />
I ndrvj clua16 +.1r r rr. rrjn-L<br />
( c hdrt N.::.1I .<br />
.'.-:' ,'l -.,r'r,fJ4<br />
h thE. ,<br />
'r{<br />
-n-+u,"<br />
1l,F rr,hl ,rLL..i, Fi ,rrng ..,U.r,r:r,.<br />
rJF:rreri ty rj+ al" 1- jnrj-ivj.ctrai::<br />
per rra<br />
. -ThF, {+i.qr!r.er Nn ji: and r:harr.<br />
46,:7 i.n{J i. vi.rJLla I !: {ron<br />
III end 1g.tZ rf th$<br />
rr 'o h,. tr.rr.l.r,n ,.r,t ..1.,r. t r.l:<br />
D :f"- rr', r.i, ., . :,, ..., ,.,..,,<br />
clc.:q<br />
.t:1.,, ,.I-ti\.,,L..,|.-<br />
.lT,<br />
,r .. j | ,,<br />
p(:)pLrlatiofl {rl:}a th{: . l*'q.ii 1,, (.:.rr-1.!(:j(::r y"<br />
floye de Arisftenc,i Region;<br />
*;;:,*;,^;i.fl.,ij]i<br />
.-".,',,<br />
ro'f r:: :r,-i,ii i,i<br />
:l:;".:iil<br />
;lji,,1I,,, jll;. -,ii..,11,<br />
l. ",.,, ^ l;":il l:,",i,t f l:f<br />
-IIiii:l]i<br />
^,^ _,-n:<br />
r;.r.q 5t|,,.t.rr,, n+ h.r::ro.J. al .r lr,.L" L<br />
ll?,;,, :!.':.rvpj{.:r<br />
F'}r,rn;d..r ..,.,p,. -r<br />
wr-th_*a 4.',:17 ,,f w-l<br />
rn(trvr.rr.(alr. ,, . L.,; ,larrd<br />
?:1,O<br />
::r:<br />
Z o+ individlrtsls .From.it"i!;s<br />
1V"<br />
COt tCluSfOr.t5<br />
i,t,::.:-<br />
2 ar,,::i<br />
8'ti Fr{Jtn I<br />
.. ll l). :i4:l<br />
!i ir tc h<br />
t i fjt, r i,:<br />
1.1$r.i lI 1l li<br />
Guarico Regionr Thi*i regjon repftfrFr.r<br />
very !!rrri:i-riIri<br />
low valLre rri1,,r.J*!<br />
+or- iir<br />
crasBFq rri anr: rv.<br />
II i r_, ,,.,-,t-...lii<br />
E hrqher L..,,<br />
valLrpsj, ,.r*,u,,,<br />
Edr(sed by thfl overr..€ixtr:.1t1+-iirtj.t.i.r<br />
re$ource,<br />
ciJ ttre;<br />
The regi.rrnal densiLy vetrrirjr 11:i;rllii!:r :tflrr. ,:r!||!f]€rrr,"d wrrn
pr€vicJlrsly r€,!portr:|d vRlLle!: frr:,fl! r:or!on{Iritiier::' j.! llrF' r.:.'!lri:rl<br />
nclt und€,r the Explotati-{:}n Frrgraff { l'lrc'rl'.j ar n.1r-'i{:tr_I. li:r)rli'r ) .<br />
187<br />
1t i5 r€c om€n'nen rl ecl . l_Jirsed fln ttr{r rFrqtrlf!} o{: i:J-r! :r'r?'i{:rfrr:<br />
study,<br />
+ollow<br />
to ban<br />
up stLtdv<br />
thi<br />
'<br />
Fl.frlort,rLrior'1 t1f t-hr .r*--,i:rl i . :!rr1: rrrifrl<br />
'i .. 'n-)' .r{ 'ttrci!]:r llril: t'ri)i:tr,llii{t<br />
j;1:,<br />
Low Apure Reg.on' fl,+ re{:ir:,nAl !:le}fr:.j ty vrlLr(: {,.r:1.1.r. ,ailhirr<br />
the interval reporlli:rJ t,]/ Aiar;;rUi.r(]n":r I l'till::: ,':L11rl llrr1.i.'r:rt { 1.'?llll)<br />
for lncalitieE |,?ithin th4 a\Ilr!r'e qLr]:F., 1'::.r, ir !+l<br />
structure o{ t-he Fopq:laLi,L}F shoers ij!!r!r {:f +hi:, ,::ri:,1,:!italit1n<br />
t^rhich it has hepn und-ir lllqr Fiigr li l t_r i'+,ilr'r,i.<br />
Hiqh ApuFe Region: ilerrsi il:,' 1!.11.t t|.i +$r<br />
5:imi I ar- +n FhnEb FErinr t,,,t i ,..<br />
198;i) Lle{ere the beqt jninq sFeciP.<br />
o{ ::!r! |::r,f ll ;,:i:irjri<br />
'| h' I iji nlr, ,af ii<br />
{ i-\,/.r r i: iiijr llrfri:i ,<br />
a,r r! | ":(!n i (]r the<br />
ThB Eire<br />
comparatlle to<br />
EtrLr{::trrr*: in tht| sir,rFe rJ: a ir.;:r.rnji]t' i:;<br />
the orlp pr_l?v:cjl-l!sly rarFLrrl.Erlr srhj!r:!r 5h,;z': f.h,r fr<br />
the reglon is (rne? rr{ the! he},,r i n?1iilr4r!.<br />
Southern APure Region: li" r4,!iflf!!:!l<br />
"i:.i,:rl.1.r v*lL{|j lcJwest o+ alI<br />
jii<br />
the reqin.r r:nviirrli!{J tr.: Ih!: -i.,re!..nt.ih dy.<br />
tili.,<br />
Th1]l<br />
extrlan;rti$n +or tfris re'.tli L :j.* 1-tr{"- ijt!.rl j l:' ,:if L t_'{ii fr.]bj h;rt j.<br />
th.r rBgiorl. !^rjth lnw<br />
q.F.rF ir r 1t,. ..nr-.r r.<br />
[rtritlrll<br />
.-, il<br />
laaler<br />
.<br />
vr.ri .i:; :in tlhnt fo.]d ir:<br />
The si:p Etrl'rcf,,rrE! qh!,-:. srJr!i:l.rr v,1 r-rL,. {!:!r iIa,niir:,- .tI<br />
and IIl ,reinq hiqher tlrn !..a:lre". l$r r:.1.n$!! lV, Nlli.rh !n.1y inr:!;rn<br />
ad t.-++eEt of t"he [:rplc] j.l,,itrrj-c]n FrLritr.i:!n ,:iyrI lh'lr p.rpLrI,rtirfr"<br />
The Fr$qr.im has ttl he ril-ju$LFd ilrli]f riri,rq lc! i:hr. rE,;irrlt$ ${:<br />
the presenl w(]rlr so t$ avc.i!:l .r de-rnr[]'*$4:r {r Lh..' nrrml-rFri_ {:}+ lh!!<br />
individ AlE (]{ c l.:r*!: IV.<br />
Wc,ody Plains Region: Tlri.Fi r(?qi1,n ril!fl|:q l,L,: l:hri ,.d I-,r::irt<br />
density valLru dLlt? to a i;troru lr.nLri!)u.irr.:,::::rrrl3i t:liii.l '::.:ir h(.,l<br />
v€:ri{y I:rbsf:rvrfig I,ht-r v;:\l r.rn,€i .jfrri l::1i !:fi,:ii:,r: i.i+ ft,ir :.tr::r}<br />
strLrEtlrr{: typr{a1 ili thr} ;ifing?ri r"rhof ,:.' lir!nLjrrrJ r,ir iri::j nnr i:rf ;.! f {j.rr<br />
than al:Lr7{4Pr,, Y€it. inl}r:l'r ;rJ t I ir'..j r. {:,r1ii1':!r. r r:!1 ri?iiiairi.i:'<br />
Fxploiterl<br />
percentajFr<br />
lindFr rrr:!,r v;r11!ei:r i{ L:hr? iillriii!r'ri:1ir, i:ii thr:<br />
r)+ !?)jfiIr:!j iiable j | | i I i v i ni r ! A 1 -. .t.i:rr rl.i:i,rl :rV l,:ir, r!! ije<br />
Hoya de Arismendi ReqicJn: Thr! ,rl,l;::ii..rl '1,'eLj,:iri ty vallre<br />
the second l"riqhelrt .r'f .11. 1 1;tl.rd:i{:cl ri::r'l j.*rij,' i r'r!rir:l: ,-nh.Jer:i .ii r!ond<br />
poF'-'ldt.ion ,,{ i. r {.I. LF.ri j..-,1rt.'<br />
Thr: si ire st r(rf: tll r.,," i!i tyI,i{ra.l. r-i :rlr i;i :! rr rlitr i ,:,,., a|i,i'-
188<br />
bl{: r:xt:f ij t:.rt:)-nrr ! fjr:r:.i [.i rtJ laf ge: nLrmher$ 1'{ individ al,'5 f rf:]m<br />
Finat<br />
rAim;rn<br />
EOncl Biansr I hE Foprri ai:i ort alr ncl;rnce tr{ itFsirtRc I a:ld<br />
tn:ri-r .l]Atilrl hy flr*,r11,r r-J ( Ltrr| rlrrnhr:r' nf jr!!J:llv j'Jrtlrl.i;<br />
Fer li'rL<br />
(r.f tsrf itri;, ifli\,. indrir:il1,r, lh,r ".lat|]":<br />
a qlrairti l.il !:/". tr l jrrL []: ,ri i:"tl<br />
.r{ li:hF: pfipL.L1.1i:ri.on lLnrler<br />
[:lr.i! '!{],"t ,,iL iirL. !'i:'f,' qi:ritrrlr,rf:; !!rl!:if' tir rll.r,:\lj.lrt :,!: rl'!r:l<br />
s l-Lrllie,:i tri:)rrriir:i{rir!r .rIJ/ lrtJlt i j<br />
f rlllolfii:iinrr iir,:rilr_ani h;rri<br />
.r++t:|! L.nr 1 I i,i' rJr '<br />
ii,:i:r'r. r', !iti I i i'l!r!)' rii: i:l'.,i iri:!r!:!iLi'fiii ii, il: i:h4: a:l jr"1:i r'rr! hrl<br />
{r.:r !:'r r}r l$rLleld, l,iirh !lr p:r:nt f .:- or1al rit. ll{:r+lrririi. ;'l' i 1'j jtr''!<br />
r:./r:r: ;i|,rl rt,t,irl ,r::i1l{1.i lfi ir::i::Jn :'r'f rrf,F!<br />
Lr ::: r,r:!r'i,i,:.,ry f I'rt:I j '. :,,:.ll,rl lr,Ii::;.,r1 i:f] ri rtiq r'.:ijilr'<br />
,,!j r .!('rl<br />
.,:<br />
ili:ri,,-,:<br />
rr{1lif !t;,1. rr!fl i(:r (rrii r,:rL.r l'irta ir-:,:i: ri jr jr r::t)if<br />
i,ri!al1r! l,i i,:i..,r: ., i'1i'i! fllei l:', {:rqt,rni,<br />
ii,,r riirir:L".ir !:!f lt:i,":f r1.;il.{:l I ii: iri,rir!_, flrf rr i}r,::1 .i!!,:fj!r<br />
rir r jrlf;1 ir r;)rj F{}r t hF L,:r]r:,il F.lajfi<br />
,::,ii.;. i !r!.rit;ridlr trrrr<br />
lr'i::ll i.ofr ijrii Fr.lrri' :iti i)rlir L:1]<br />
.Jflinf<br />
FIELID6RAFIA<br />
AYalitrlrii:irlr r,rt'," ,1.::i i::!:nioti,i"r .i, !:it:ir,n, rlrr ,irrri i'r|-: l!:i {} b":rlrA<br />
i lli:rlinr:\i.r- ', -!:i- l,li.l.i !.1.','1 l.' r e:r: 1'':r l'll triirr:i ':i:'<br />
t:i:ri:.;rir:r t:: r:rr',i. ijfj, ;1 -t :rri<br />
'r:lr:r|ii {Vl}rf]l;i:'!ela) '<br />
lrl l.l/lr:i. A,r:, i::.-:|:i 8r4r i.(:jtrr:ii:' Ilrl,i'(r itrdi+i: llr lr.:! |"lq { (:l!i<br />
Ulijf:]<br />
{: tijt"irjtiJ..il. L:,j,ji.-: -!fl lios L.lan{:ri! i.l,:!:ir:lii'fltrl1'!:L d. L/ 1, r l:'r, rp li ,i, Vi(ii<br />
fii ivr,r,.+tr r: fl:jt,l:rrrrl fal l. 11.r :",ilr;,: ir,r:<br />
l,i illr<br />
!:i'iJ\ii!fL. ti"A, dnd,l , A. O:lXflN, lilhlrr1;e:i dfv !]t-.$]3r)fr l]r.{:)]. 'l,' ',i<br />
f:t:.!lnl ,,:1!;!, .],-l!l:l !.i.r'L.q!l-!L-||! lrn{ [fia:: !.r8]ia::.r!!r!lArr i i'r:,':: I'i:'ir'<br />
$ir . i:r,.r1. t\irt .:5 1,:71-i) irj,. l:lr:i/ ;lrii<br />
.|'J'l]:|ii]l\jA|]||\.i|'].1i]li]ri'Li,'li'';]:l:j:L:]qy.rd|ii]i.it.:;.],!|<br />
ll.ri$:!, i!:'lIlllrl!:i f,-ll .!lii:Jl.il..i-i,l-:i<br />
' -i!1 'lrri! 1:ir1r"il t'|!141r::Lri": i;trr l-i.rrl': '<br />
i\f1i::!:.:i.i.i...}].:]l:irf'0j!rilnti.'{|1:|!ri:ll{:,:!.i|^d11Athi|ii(i!ir::.Lr1+illl(:;ji]]<br />
v#rsl.i; 1rf !:r: r' jil;i rlr f .rrl-:.:1 li: , r I I, i- I rniiir l. {;f l:11|] rirlilliiil::!r,+fr'11<br />
'I'i,r ri.rqr:!,r.,'1 ir.,1 r,., r:. fr'!i:i !r!.{rt)l!y, llrl./!'!r!irLy n{ f 1fl'-ri ;r.
1. -Guarico<br />
2.-Baio Apu&<br />
3.-Apuje MeridiDnEl<br />
4.-Alto Alue<br />
5.-Ho]'a de Arj.smendi<br />
6.-Lliro3 boscogog<br />
?.-AJEa dc irdluencia del Orircco<br />
Alto Apure<br />
Bajo Apur€<br />
Apure Merid.<br />
Gu6rico<br />
H. Arizmeodi<br />
Llanos Bosc.<br />
Fe3b de los Llanog<br />
Fig. 1,- Los Llanos Inundables y su divisi6n<br />
Superlicie Total (ha)<br />
2.662.296<br />
571.389<br />
1.262.M9<br />
784,475<br />
615,342<br />
3.114.384<br />
Superficie Censada(ha)<br />
25t.95626<br />
78.t74<br />
234.126,51<br />
69,297<br />
95.r54<br />
r93.873,50<br />
9,46<br />
13,86<br />
18,55<br />
8,83<br />
15,46<br />
6,23
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lFig. Z. Hirtogru*"t d. ..t.*tur", du r"rn"n", p* R.st6;l<br />
Regidn Alto Apure Regi6n Bajo Apure<br />
191<br />
a:ra* ltl clrse Iv Clase 11 Clase lll Dlosr lV<br />
Regi6n Apure Melidional<br />
Ilegi6n Guirico<br />
Cl.$r Ill cln!.lV ClEse ll Cl6ee lll C)ase lv<br />
Regi6n Llrrnos Boscosos Regi6n Hoya de Arismendi
192<br />
STATUIS DB ILAS POBLAGICINES<br />
DE BABA<br />
{edma wffitu} SOMETIDAS A<br />
APR@VBGHANfiNENT@"<br />
AlvrrD rtrbillo* & Jora Avsnrgl*u.<br />
* $nriqiD A!li*}Do FR+IAUHA, Edf. Crnrio Orrt., M.zruilr! C *:$ 1010, V.!r .tr.<br />
A$!a ErFiola ia C0o!*nri6[ Eema.ric*ra, CdL titr]hirro, Qti.l+ l0r Lr C$t.lt tr, Crrrrr, \L!.zudr_<br />
lNTRODUCCION:<br />
Desde I.!81 :e h;r<br />
"'enid+<br />
desarrrll.udt, en lrr Llan+s lrrundaHes de Verurr:ela<br />
el "Fr+grama de Apr,:','erlnmienia f,omercial de la Especie Baba [C--z,lmn<br />
i;'r;rr.diri"tJ". ei_.Llrr^d esta regdado por la F.e;o1rni;.rn N! l.?,9 de fecha 13/ l2/g l,<br />
pruhhtarla en la Sai_=eta Oficral Ns .14.l![ del 33i lJ/! I d: la F.epirblira de<br />
'{ernzuela.<br />
_ EntJE la-i hnses miis lr$orlarrt'rs que ngEn el mencior.ado Ptograma, podemos<br />
cli,, 1,.1s si.qrxerrtr-,s:<br />
- !rni'. :rE FErrril€ Lr{rsF:tiar m mdsrno del 5,e?d de la p,ltrlaDidn censada.<br />
- :rl,r ::e cossrlu a la rlase IV, irrt€grdda prr mar:hos mayores a l, gB mt ,le<br />
hqqrtud l.,rlal<br />
- nn.r8 Fe-r'rutr rtosechal enaqr_ull3s gn quellas loca.lidades que reporleD porcentajes<br />
de ':1a::,: IY irrfen,-rres al 15?.i<br />
Enjt Eslrlr crilErlos se lta regl.dnd':) la co:echa en los ullimos diez aflss. rr,n urn<br />
paLi-"a en 1.986, en la cual s* erralu+ la: cosucl.ns otorgad.as hcta El molrunt3,<br />
prl|luclenrli:r:e comr resuitadr_i drl misnrt rura redu:cidn en laq tasas de extxacclon de<br />
la p'rblaci6n<br />
. - El+trjeiivi..r !'rlrDipa.l dEl presenlE B:ludi+ es detern:rnar el ei'ecl,o que a temdo<br />
el Frr-rgr'tura :i,tre lar poblmr+n* nalrrnlEs de la esDecre que se han ,,€nido<br />
lplo'"P|hindn, l esd+ ru punlo rjp r,tsla c,rlllahvo y cudnhtattvo.<br />
AREA DE ESTUDIO-<br />
En la fig. I se identifican hs sei: regrorns naturales estudiadas en los Llanos<br />
Inundables, en las cuales se des rolla el Pr+grama de Aprol,eclurrner$o de la espeue.<br />
.<br />
Las cararteristims que defirun rada regron vienen dadas por la preserun o no<br />
d.e garceros, dellas rnternos, mlidad de nutrienres, grado de inLuria*i6n de las tierras y<br />
tipr-: de srrelo, tldar ellas r:arart€risticas que se eltima que [enen relari6n con la
densidad de las poblaciones de baba (tabla I ).<br />
MATERIALES Y METODOS-<br />
193<br />
Se realizaron censos endos tempordas correspondientes a los mese de sequia.<br />
La primera deabnlamayode 1.941y, la obade ernro a lrio de 1.992.<br />
La derridd de la poblci6n se midi6 con certsos nocturnos, contardo tdos los<br />
individuos observados por nEdio de faros pilotos y linlernas de frentE. l.a estructua<br />
de larnafros e realiz6 tffto de dia como de rnche, utilizado el rftndo dscriio por<br />
AFrzagrnna (1.983).<br />
RESULTADOS.<br />
Regril4lto-t\pue.<br />
La regi6n Alto Apure abarca un suprficie de 2.ffiZ2% ha, de las cuales<br />
freron cerxadas runs 251.956 ha, lo que repr€senta el 9,467o del area l,otal,<br />
estitniindose una poblaciin fu
194<br />
poco desvida beia la cl6e II (tabla 2).<br />
Reei6n Grffco:<br />
La regr6n Guiirico abarca rrn sqerficie de 784-t75 ba, de lr cules se<br />
cerraron 69.296 ha, lo qtc representa el 8,83% del area total, estirnrdose rm lolal de<br />
8.792 idividuos, para run densidad de 0, l3 itd/14 (tabla 2).<br />
La eshutrra de tarnaflos mr:estra ur 70,47o de individuos clase ll, 2,6% de la<br />
clase III y un 7,0% para la clase IY. El histograma presenta u:a fornn de escalera,<br />
lipica de zoras sobre e:Elotadc (fig. 2 y tabla 2).<br />
Reoon Uanos Boscosos<br />
Bta regi6n cubre urn superficie de 3. t 14.384 ha, de las cmles se censaron<br />
unas 193.873 ha, lo qrn rcpresenta el 6p57o del arm t/otal de la regr6n. Fwron<br />
estrmadas unas 28.886 babas para urn dersidad de 0, l5 ird/ha.<br />
El histcgrama y es|Juctula de tanufios {fig. 2 y tabla 2) presenta rma fornn de<br />
escalera, conun 46,3% de irdidduos de la clase Il, 35,6% paralaclase lll y un 18, I %<br />
de la poblmi6n en la clase IV.<br />
Reet0LttsE-de<br />
- AagrnErdr:<br />
La iegi6n Hop de Arisnerd.i abarca una superficie de 6 I 5. 342 ln, censardose<br />
unas 95 154 ha lo que equrvale a un 15,46% del area tolal, estrnmndose ura poblaci6n<br />
de 32.856 babas, equi\ralente a una densldad de 0,35 ind/ha.<br />
La stxuchrae hislogranra de tamaflos (tabla 2 y fig. 2) presenta una forura de<br />
pirdmide lipica de zonas bien manejdas , con tm 48,27o de individuos de clase II,<br />
:6, 8fo para la clase I I I y 2 3, B7o de indivtdllos clde IV.<br />
RESUI=T*EoS - (rNcLur\c sE:,<br />
BeciesAlslp.$e:<br />
La demidad de la regtdn es ser@Fnle a la reportada en la literatura pa? la<br />
zona {Ayarz4grrrm, 1.983), antes de' implenenlarse el Programa de<br />
Aprormhamiento de la espcie.<br />
La estnEtura de tannios en forma de piriilrrrde tarnbrdn coirnide con lo<br />
antEnorfi€nte reporlado, demoshanlo qr.E es um de la mejores zonas para el<br />
aprovechamienio del recurso.<br />
Regi6n - Bap Ap1rg:<br />
La iterridd regroml obtenida se erruentra dentro del interrnlo repoddo por
195<br />
SeiJ6 (l.gEd) en localiddes del estado Aprre. Sin embargo la estructra mrstra<br />
sintornas del aprolechamienio al cual a estado sonEtida en los iltirnos di€z afios.<br />
ReslgaApge Mendignal:<br />
La derridd regio:ral es la rns baja de todas las reglores estr.diadas. La rZz6n<br />
qrn explica esb lncho as la calidad del hibital dorde las agrm sou pobres en<br />
nutnentes y por lo tanio la disponibilidad de alirEnlo para la eslecie es baj4 lo cual<br />
deternum la abundaruia de la misna<br />
La estructura de taffaffos presenti lorus senEjantEs enlre la c16e ll y la<br />
clase III, sierdo mayores qrc la de la clme IV, lo que.podria significar un efecto del<br />
Progratra de Aprornchamiento de la poblaci6n, el cual debe ajuslarse a loli dabs<br />
obtenidos en el preseutE estudio para no prodrnir urn disnunrui6n de los indtvtduos<br />
que integrana laclase IV:<br />
Region ,Suilrjlqg:<br />
La eslructura que sE r€poria presenla un muy bajo ',ralor para la clase IV 1' la<br />
clase IIl, en contraste con rm alto ralor para la clast II, prodruto de una sotre<br />
explotacr6u del recurso.<br />
La dersidad regrornl tarnbidn muestra un bap val+r, en compamcton con lc<br />
reportado por Thorbjanranson {1.990) en localidades no sometidas a el Frograma de<br />
Aprorecbamienlo de la especre.<br />
BasaDlonos en estos resultados se recomienda vedar el recurss haita qw ur<br />
trabap sinular demueske que la poblaci6n se ha recuprdo.<br />
Refl pn_Llgnos-EgEqgssr,<br />
Esla re$on presenta el lercer lalor mits bap de densidad, produto de urn<br />
frnrte presron de cazr, qw se corrobora al ohseruar la forma de escalera y los<br />
valores que se obtiercn en la esaucbra de larxaflo, lipica de zonas donde la crceria ha<br />
sido nayor de la permitid4 aunqw todada queda recurso para aprowchar bap ua<br />
nuera politim, basado ;n una disn]lnrridn del porcentale de irdividuos clase IV a<br />
cosechar.<br />
RegionHoE! 54wsL:<br />
La derurdad obieruda es la segrurda mas alta de lo'das las regrones esfidiada,<br />
demostrardo que e)flste urn hrcnn poblacidn de babas.<br />
La eJtnEfura de tamafios e6 caracteristica de zooas sorEttdas a un marcJo<br />
sosterudo, existiendo importantes canlidades de idivrdltr clase IV.
196<br />
,:4rnhsi4nes Finalesl<br />
La abundarura de la poblaciin de 1a baba estinmda como ntnuro de tnlividuos<br />
For heclirea de terreno, solamenle indica Bl sl.atrrs de la poblaci6n desde un punto de<br />
\,"ista cmnhtaLr!'o.<br />
En canbro la esl.rmtura de tatniriio: indrca la ',-alidal de lm !',:blarl'rnes<br />
estrdiadm y tomo hm srdo alectads por el Fru,qr:rma de ,..lI i t;t,ll-r3nrentd<br />
Ct'nrer[ial a] [rra1 eslan snirEtadaj<br />
En el Lla:l: rlurdn hsh.ffE }Er:lrsn qu8 Fr:rdt'in atrfnvEc}lnr'se, prrselimrrdo<br />
grander diferencr*: p.tr reglin, 1t que al,g.uras harr stdi; inlrr apri'nrlrrda: 7 oins<br />
iobre npror.Etl]nd;D.<br />
Es wcesan." irazar p{rlitrEs de aF}'1:r'lEchrTfietrt:' Fart cada regt,rn }. i:':, ,-l.e<br />
nrarnra global, sretrdo el cruo de 1a P,eglon iit.r;ri 11r.: rirle deh* .,'El1;1rse<br />
El niurer.i r-1: hahe-q eli li L13n]:: Filra tma e::!1,1iffi,:,1-r ra[16nd] Fldriil llsllf' eri<br />
el ,rrd r:n ,1e 5 0 LlLl tl .r 7 0. ll Ll ll q Emnialss/;lfi ,,<br />
BIBLIOCRAFIA-<br />
Ayarabrnn4 J.S. 1983. hologta del Cairnamde anteops o bba ltiainza tnwdix<br />
L. ) En lo,s Lleo6 de Apurt. (Verczrnla) Dofuna t 0: 7- 136.<br />
Seip, A.E. 1986. Estinncior*s poblaionales de babm I Cenatu cr1rr.rlillx) Lnltr.<br />
Uano6 ocridentales de Verczrnla. Vida silvestre reotropical. (l): 24-30.<br />
Slalon, M. A. ad i.A, Dxon. 1975. Strdies on tlz dry s€ason biology of c€ra?EE<br />
rctz;rdttw az:|?'dzhr from tln Vernzrrlan Llaos. Mern Soc. Cierc. Nat. 35:237ffi.<br />
Th,:rtlunarso4 ,i. B. l?gtl. E,:nliBl' and beln'ri,,r oi lhe specemled lniftilri lf--i/ir,t*r<br />
;'arr-/-d;e.'J i}] tlE ,]srtr.d Ye r:r,Elatr Llarros. A dts.rerlatir.:n presentrd hi a grixlrratr<br />
scll",.iil .,i '']re ljm<br />
"'ersil]'<br />
tf Fl'rrrda rn partial frrlsillneni. cf the rgquerimenLc thr ihe<br />
,ieeree ,ri D'lior ,.,i Plui ,saf?. Llru',iprsd'f of Flortda.
l. -Guirico<br />
?.-Bajo ApurE<br />
3. -Apure l"teridional<br />
4 . -Alto Alure<br />
5.-Hoya de ArbrErdi<br />
6.-Llanos boscosos<br />
?. -Aiee de hlhrncia del Oril|oco<br />
Alto Apur€<br />
Bajo Apure<br />
Apure Medd.<br />
Gufrico<br />
H. Arizmendi<br />
Llanos Bosc,<br />
Resb de los LlorLog<br />
Fig, 1.- Los Llanos Inundables y su divisi6n<br />
Superficie Total (ha) Superffcie Censada(ha)<br />
2.662.296<br />
571.389<br />
t.262.079<br />
744W5<br />
615.342<br />
3.114.384<br />
TOTAL<br />
LLANOS INUNDA. 9.010.365<br />
2s1.9s626<br />
78.174<br />
234,126,5r<br />
69.297<br />
95.r54<br />
193.873,50<br />
922.581,27<br />
9,46<br />
13,86<br />
r8,55<br />
8,83<br />
t5,46<br />
6,23
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Fis. 2.- Histoeramas de estructuras de tamanos n<br />
Regidn Alto Apure<br />
Regi6n Apure Meridional<br />
Regi6n Bajo Apure<br />
199<br />
c1€se ll Cl6se lll Clase lv<br />
Regi6n Guirico<br />
Clase lll Clase lV<br />
Regi6n Llanos Boscosos Regi6n Hoya de Arismendi
2N<br />
Agonistic Social Behavior of Broad-nosed Caiman (Qaiman<br />
lati rostris) in Captivity: lm pl ications to Reproduetirre Managemenl<br />
Luciano M. V€rdad€<br />
CIZBAS / ESALA<br />
University of Sao Paulo<br />
Caixa Postal Og<br />
Piracicaba 134OO SP BRAZIL
Agonastic social behaviot of broad-nosed caiman lf-aiman laklikiS] in<br />
captivity: implications to reptoductive management<br />
Lu':iano M. verdade<br />
CIZBs\5 / ESALQ<br />
Urrivetsity of 5 3':' Faul.'<br />
Cai:+a Pr,rstal ll9<br />
1-a4DO Pirar:icaba 5P<br />
E F.i;llL<br />
20t<br />
l.,lanagernent Frogfarornes ol clocrrddi3ns in captivity may implv in keeping<br />
adults ior reproductilln ond / or rearin,l lqunq* t"ith lhe nim oi economlc use.<br />
.onser\r.itinri E f the .,:Fe,lies and educ.stiDr' [Bustard, .t 571 and Lanq. I 587]<br />
The !,r.,,ill beha'.,rot af a sFecies, desptte the differencas betr'"{een wild and<br />
capta\.e-born .rninr3lg. alfe*ls direcllg its cD'sptsc,ifir-, tolerance level and *s<br />
aggres"-iue beha'ior. Theteiore it ie decisi'e for the success of keeFing D€Ftive<br />
u:c'lonies. ilrdependentlv sf the Frogram obiecti"ec lLang. 1 987J.<br />
The study of rtoc,odili.rn soEial behaviDr irl the +'rild has beerr generally €<br />
diflicrdt u-rr rrearly impossihle tasl'. ber:arrse rrrost nf its artivity is Ferformed ']t or<br />
below the suti.:ce of the tlaler. Hotevet, progtess ha: been made thtough studies<br />
in cdFtivity, berlelited by the latqe numbet crf ,:aptive breeding programs which<br />
have been established duririg the last lv+,:' decader The':a studies all,lw ihe<br />
ei€ftination. dt close tarrge. of certairr behaviors exhibited by animals accustomed<br />
to the Dresence of humans. r+hich could hardly be documented in the wild Ctespite<br />
trigh anirodl densities in caFli'/it-v lead to an irrcrease Lrf sEcidl encowlets r.rany of<br />
the obsen ed intera,:liann are usually :.Fec'ifiD dnd Feculiai to tha social behavior of<br />
n Fartic,r ar speeies fLang. 1 989]<br />
Most ol these -rh-rdies in caFtivdy have teveaied delaile of mating. leedino<br />
teDhniques. rate of youngs. atrd :+onre social behaviots more similar ttr that af birds<br />
and mammals ll'ran that o[ othsr reptiles [Vliet- 19F2 and 1586]<br />
Ganick et ot. fl378l describe,J lS diflerent k'inds of socidl communacat,ons<br />
lor Amedaan alliqa|:t. eight visual. six vocal .rnd four non-vocal acoustic eigns.<br />
rnr-'st Dl them dscrete and non-gtadual. that is- being demonstrated irr a corrtplete<br />
,aay or not being demonsttated et all. Ayarzaquena [l383] described for Cainen<br />
crocodilus crocodilus in Verrezuela 13 visr-ral and I sound kinds of social<br />
.otnmunieatio.', iix vocal and three non-vocal. Vtiet (1989) includes not only visual<br />
arrd sourrd signols but also corrrplex sound and possibly tdctile iorrmurlcohon<br />
channels among adult animtsls oi both sexes. Lazell & Spitzer [19771 described a
202<br />
possiblB Fl€y behaviot shotaed b-u lrne ],oung Ameri(:an dllitratDr, which t\,ould be<br />
new amEng other reptiles.<br />
The dispotilion of the communictstiolr char*rels trelween visual and:ound<br />
$ystem:6nlang thE several species of crocDdilians seems to sulle. sEle':ti'Je<br />
Ftessure lr'trm their habitats. Visual siqne seem tD be mfrr€ efticier't in oper'<br />
envitonments. .such as those ocEupied by CrcCgdylqg aqutus and f, njlqtiplC.<br />
sounds +eeft tB be mc're efficiei't in dErr!:e vegetated s{..'amps. ru6h.is ttrol'e<br />
occuFied by Ametican alligator [Gorrick B, Lang. l977]. Tlre.:dult ar'imal dens,it! ir'<br />
a patticular atea is also related to the e8istence and inten'rit-u $f cert6ir-r behaviors<br />
or social Eommunicati'rn signals lv.-liet. 1983].<br />
Aggressive beh.ivior among territorial males during the reFroducti.re rt.rtion in<br />
Nile croc,rdile qrouFs was observed by Cott n961l. Adults can alsD thre€iEn ur<br />
sccasionalb attack youngs. mdinls tr'hen the1, get clc,'re tcr hatchlinq'.r. as noted by<br />
Hunl [1971J in CrqEslflUs E{uslElli in cdFtiriity. F.n American alligalor adult<br />
female may also ati€ck sub-adults in the wild ra+hen they get Elqser l[.r,in I 5 meters<br />
of her nest [Hunt. 199OJ. Ttre aggre:sive behevi']r ol adult flgqgdyfuS Do.rgsus<br />
ton'€rd sub-adults over 90 to 120 cBntimeters long in certain places in /rustrnli.t is<br />
lhe main cause fst their elimination ol place: oc,:upied bg adulte lhlesrel i"<br />
!'Drlicek. ! 9871. Even yor:ng Ametir:an alligator.l r.r.:J, hE a!!reslLre Enicirrg<br />
theriselve$ in captivity if placed in high arrirrral derrsity enclosures, despite rrf beinq<br />
c,r.!e Df the most socidl sFeeies of the Drder Crocodllia paanen & Mcl.lea:re. 1387J<br />
Accotding to Lanq [13871, infornration rel.lted lo lhe :ac'i€l ,]r!tsr iatr,ln oi .r<br />
spe*ies in the +vild can pro'ride qorrd directions for the plarrning.,i r-rocodiliat-r:<br />
c.:ptive breeding. Territoriil :Felries tend to be less so,:ial ,:nd can ber:r-,me<br />
.rgglessilie towcrd allies. These species require nrore area in their reF,roduEtive<br />
pens and / Dr must be keFt i*''f,laled, irr pairs. or in small grFups itf orre nrale with<br />
sonte fernalBs. lln the othet hand. specier rnrhich forrr'r large:az,:n.:l graups ior<br />
reFrcduction tend to be more sDcial and permit d larqer populBtiFn densitu rrr<br />
caPtivity. 5Fecies like Americen alligator nnd the e.tuarine c-,r,-,codile [f- g.{|[ ga$J<br />
,tan be Gorsideted the oppasite extrernes in relation t.J the fealure abc'.re.<br />
However. there is no s.rfe end fir'al inform€tion dbolrt some specie.s of c,ro*odili.:r'ir<br />
CgiEcD clacadfus is still found in large groups fAyar=aguena. I 583 and L]or;ul.:.<br />
19701. but ttre same is no lclnger lrue for the brodd-r'osed csimon [Flontes. 1383,<br />
Laniera. I 990; Verdade & Lavorenti. 1 930 and Yanaski. l35Dl. althrrr-rgli it i.:<br />
unknown if this sFecies originalll'used to 'orrn large s':cial gri:ups.<br />
Materials and Methods<br />
Cases of agonistic interacti,lns.. which resullEd in h.3rms lD at len.Jt Ene ':,i the<br />
involued animels, rnrere reported from Augu-it l5B7 t'r DecembBr.l39l dt the<br />
lacililies of the Captive Breeding Progrom of the broad-nosed cairrran ol ESALQ /<br />
University ol 55o Paulo. PiraciDaba, Brazil.<br />
Hatms were identified at typical skin FerfDr€tions cauied b_9 bites.
203<br />
Durin-q this period, a tatal of 188 animals wete splead in 34 enclosutes..<br />
divided into 'frouFs with two to thity animals, witlr a petmdnence time per animal<br />
Fer enElosure rdnging fiom one month to fout years, in order to meet the Pt,>gram<br />
techrrc€l-otreraliondl needs.<br />
Results and Discussion<br />
The number of ngonistie inlerdctions reparted during the study period c€n be<br />
considered small. H,rrnrever, tlley replesented almost l5Z af the global mottality<br />
rate of the Prr:gtarrr, with almost B0ia of the cases repor[ed hd?ing lesulted in death<br />
ot one of the involved aninrals. ll seems to be related to bicterial infections<br />
relulled fr,rm the harms. as destrihed by Farnos et al. fin press] andZwart [1578]'<br />
l"lo,:t of ttre attaL:|..,,i 'rccured taon in the first day of the gtoup assembly or<br />
the ne,,^r individual inhoduction itltr-l the gro,rp. Howevet- sometimes the €nimals<br />
rFEnt nirre ('f even len rrontirs livtng apparently peocefulllt togelher before fiqhtin-q<br />
iFiq. 1i. This s,:mpli|rg does not petmii a concluaion about the tequired period lo<br />
thJ seitlenerrt ol a new lrieratc:frical :ttuctute into a grl.luF- like a "pecking ordel'<br />
ol domestic fol\,|s. but Fossibly the filst-dag agottistic interactions must have distinct<br />
ceuses of those occuted monlhs later. A first-d€y fight seems obviously to be<br />
resulted of the introductian sf a nE+,t individudl in a stable gloup or of the group<br />
assemhly iteelf through fomerly isolated animals. On the olhe. h€nd, sometimes the<br />
apparent social balance af a grr-rup may be btoken up by something new. like the<br />
approach of the reploduclive petiod. ,r sudden we€ther change, or any othel<br />
stressing fa':,tor such as Dapturing hy humans. etc.<br />
The high freqr"rence of lights itrvolving iust t$ro animals lalmost 352] ean be<br />
due to tr.ao tactors: samplinq etror. since the gtoups assemblages did nol follow a<br />
research design but the immBdiate opelational needs of the Program; or the gratel<br />
lendence ol rsolated animals fight r'{llerr suddenlv put in touch with co-specifics.<br />
This would be similar to wlrat Magnus=on [1986] desctibed for,rverhunted wild<br />
populations, where the rernaining individuals may become more tellitorials The<br />
most frequent fights in two-€ninrsl groups [Fig. 2l in relation to latqer etisting groups<br />
may - be lelated to the faclots abc,ve.<br />
The enclosure animdl density itltetleres ternatkably in the aqressi'reness of<br />
indi'riduals into a gaup. In qenetal en increase itr the animal density tesults in the<br />
increase of the social meeting frequence. and consequently in the agressiveness<br />
of the animals lLanq. l3B7]. Ho+veve,. the occulence of agonistic interactions<br />
nror'? fiequently in the density enclosures of 0.0? to 0.01 animal Fer square metel in<br />
felation to othets up to 0.1 animal per square meter shows that passibly animal<br />
density v.,as not the main cautie fot agonistic intetactians in this case [Fig 3].<br />
The se8 of involved animals- conttary lo what could be suFpDsed" did not<br />
inlerlere in the occulence of agonistic inte.actiole. In other words: the frequence<br />
of tights imong animals of the same ser w€s the same ol amotrg animals of the
204<br />
opFo:rite sEh iFiq. 41. lf the sEnle occ r h,ith the rqild FBFul.ftitrni- i.lrp can infEr thnl<br />
the species Fossibly {:nnntri stnnd Isrge rs.-rrrr.rl gtr-ruF,:; altl-'Duqh :.om':tir'ie; it i;<br />
corrsidered ns sDcial as Caiqag cr11cgtlills [Lang. 13S7].<br />
The oriqin of the anirnals 14.'a$.in imporlant factor. tut not decisi'/e. to the<br />
o6rur+n.e ol agor')isli'.,- internctions. *'rc,ur.rd 85t:,:. rt tlie lights rtrvoh,ed anirnale hon-r<br />
diflerent otigiti [Fig. 51. Howevet. !tressinq siluatians ,:,r-ich es c,aFture,<br />
imflr:,bili:aticn and clrange ol encloirure .iar] Lrredl. uF the sc'ci.3l rlnr':ture of a<br />
grouF even terrrF,:rarily. resullirrg in fights.<br />
The ag'rr.ristic intBroctrons inrrolved Fredorninantlf the biggest anin.rah of the<br />
c.rl,rr,y [Fig. lj]. ',,{} rat is tompatible lo the r_,9;s1,.';1|o.is ai.5.yar:;guena [1583J for<br />
Caiman cleqqdilg* craaqdilu$ durirE the summer time rn the Venezuelan<br />
"llanor" Ihere r"+as no srqrriii*arrt difference L'etrq,eerr ar'irrals of ihe sarire sr?e<br />
[agtessc,r and aggreijsed srrout'?errt length ratic, ftorn 0.8 tc' 1.2J ,:nd anirrrals of<br />
dilferent riza [aggrel:or and aggre:;sed 5n,:,ut-vartt lEr'oth ratio honr LJ l+ 1 6j. in<br />
relstic,n ln t["ie occ,.]rBncE af fiqhtr lFig. 7i. Ho,fle'rer, lhe.rggre:-rrat r eqgres-ted<br />
v+eighl ratio seenr.t tr' be. deci:i're. h4'rst ol the fiqhis involved individu,:ls +&ich the<br />
+rerqht ratio 'r.ra+ up to 1.i lFirr. Bj. Thie diii*rence between eize and ',vaight retios<br />
;: a predeternrirrir''g laclrrr fr:r liglrl car' be r*latid lo il-,e !r.!,etl-r ,:ur'.re of<br />
crocodilian;. r"',here fr':,rn rertarn,:,ize ot'i;rnell lengll-i r-rcrea;eJ are hllowed t'9<br />
relatively bigqer weiqlrt geins [i,lcllhenn-y. 1335, Cr'ul.orl et ,31 ] 97il: ,loarr*n L<br />
h.lcl.,lease. l97li and l$i!. Hational Eesearch llouncil. l9E3; \'"r*bh et al.- 1983<br />
arrd Etisbit-r. 19901.<br />
The peal,. of aqanishD iriler.-ctioni alonq ihe year ccrin':ide:. 'J,rith lhe<br />
beltn'rninq f,,1 thE rFFrr,'du-tr'/F ,r,-:tivitie:r [Fig 9] There i:: r'ro !.,E!eciiic inlorrr,sti,--ir' fBr<br />
broad'nosed cdinr r about the trme peflod bet,,.reetl E:c,p(lEtisn ,3nd egq'ln-ytl1:t-<br />
Lsrseir *t al. ll gllBl Dite: a g*riod of :pprr-,xirnat*lly E l\'eel-.: b*t{a,Eer, o\jr.ilatiL-ln<br />
[ar'd probably *rrpr-rlatiorrJ arrd egg-layirrltr lor lhe ArnerEan alftgator. lf this frottern j3<br />
lhe !ame f 'lr broad-n,:red 6aiman. lhe Fenh ,tri occ urencE Dl iightt corncide r''rith<br />
lhe copulation periad. This ,,i'auld ,rlres3 the role ul :e;{ual h'lrmones,rn the<br />
aggresive behavic'r ol the anirnal,. ir-r cc,n:rnan.-,e t.-, tijiilerrberqer [1381J, Eihnt]<br />
Wilson [19f51. Leshner [ 378]. ond Frain [1!7311. There wos ir,] report Df tir:ihts<br />
hom Aptil lo May. This i: proL'ably d,re lrr lhe end of reproducti're cyele arrd lhe<br />
reduciion of qener3l a':tF/it-! c'f the tsnim,3lr bv the auh-mn [Lang. 13871.<br />
IWilsoh,EO. 1975. Soclobiologv: the n€'./ st/rilhesis CJmbricigo, Mass.:B€lknsF Press<br />
L€shner. A 1978. An inlroduLlion lo behavioral endocrindlosv. NewYorl.r L)xord Univ.<br />
Brain, P.F- 1979. Elecls otthe t,ormones ollhe pnuitary gonadalaxis on b€'haviour. p.155-<br />
329 In: Ctromical influ6noes on behav,6ur. K Brown o S J Cooper lEdr l. New York.<br />
Acad€nric Pregs
Conclusions<br />
205<br />
AJ Alth*ugfr agonrrhc rt'rtetaLrtrr:,r'ri Inny nrJt IEprB::ent the rrrain ':ause of<br />
rnortalit!t rn c.iptitirt!. they enrr significantll,r rBduce a.nptrve col,rnv of braad-nDsed<br />
caiman.<br />
El l',{o.:t,ri iha.lgBni,:lic int,"I-ttiDn,i ott:ur by the introdu.tiBn ol arr animal<br />
into =n en*l,:i:ure fqtrrret!t orcuF,ied b-r' = lorrel-v ttrd*iidt.t:l ThBIefore. the<br />
Fe.tnanence cf knlated atrirrr'eh iot lorrq p-:ri'.'d:, :houlci be a'.,oided-<br />
t:] |'l':':! ':i tl're ag!-rn!ltii- rnte!n'rtinno- .t'.ut durirrg ihe fifs! dai,' c'i Lhe !I,lr-lF<br />
aslernblv ,:r the nelv in,jiridual intr.ducli.rtl inlo tlrE SrL-ruF. Ti'retef c,re- thi'; thor-"rld<br />
be c,r-,n:rrdered the nrinirrurr pariod,:,1 E net"r qt.rLrF Fbsel'i-liqr' ih order to isolate<br />
rnd rerrrr-rve if'6 rndt'/idunl whir,h t.,, :rrt.rEotrtued.<br />
tr I .rirrirrral',. L'f the :.ame res CD rrot pre.Enl ; different tendency to fight than<br />
atirnal.: oi diflerent ser:. Therei':te- rer seemE nDl tD be deciei+e in rel.rtion to<br />
eor:i.:i aqtes:.ive bef':viot,,3t len;t in caFtivity<br />
Eibic,;t of the,rqtrnislrc rnletdction! o'r,:ur amlllg ddult$ with differetrt oriqin<br />
Thereff,re. rotl3iderinq the geneti.- manngefirent of the aLrlDnt. rrel4 teprodt-lctF/e<br />
qroups should F,,a arserntled t5. -f.-'rlrrgs ar lrb-adultJ.<br />
Fl Fept':durtive gro,-rFi sft.ruld F ltferabll' be .ersernbled by animals whicfr<br />
tl'e $,"itlht t,Jhu dc, rlnl erceed Li.<br />
Gi The no:t adeqr-rnlF. perioll to ieprc,ducti'Je gloup ntsenrtrly in 5Eo Faula<br />
State- Erazii tt lerms Lrf ngqtt:Eive social behaviot, seeris til be the autun-,n' Irorrr<br />
Aoril 1o,,1|Jne<br />
Acknowledgements<br />
f'I,r.664tr-032<br />
Fr,indo h,iut-,di.:l pern 3 Natultzd - t'v WF. f'tor:ess<br />
Inrtiirt,r de P*sqr-risas e E:tndar F[:re':tais - IFEF<br />
Frrnda;.Jr-r de E studo;.5.gririos "Lui: de Queire=" . FEALQ
206<br />
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218<br />
Status of Captive Population of Broad-nosed Caiman (C.atmao<br />
lqluos&id in Brazil<br />
Luciano M. Verdad€* & M.E.B. Santiago*"<br />
' Studbook-keeper of the Broad-nosed Caiman Regional Studbook<br />
CIZBAS / ESALQ<br />
University of Sao Paulo<br />
Caixa Postal 09<br />
Piracicaba | 34OO SP BRAZIL<br />
** Parque Zool6qico Municipal d€ Bauru<br />
Pg. das Cerej€iras. 1- 59<br />
Caixa Postal 271<br />
Bauru 1 7'l OO SP BRAZIL
219<br />
Stdtus ot captiye population of broad-nosed caiman lCnimnn laUlqsldsJ in<br />
Erazil<br />
Luciano M. Verdade["] & M.E.B. Santiago[."]<br />
["] Studbook-keeper Df the broad-nosed caiman Regional Studbook<br />
CIZBAS / ESALQ / University of 56o Paulo<br />
Cx. P. 05 13400 Piracicaba SP BFIAZIL<br />
[*"J Parq']e Zool6qico h,lunicipal de B autu<br />
Pq. das Cereleiras. 1 -59<br />
Cx.P.2?1 17100 Bauru 5F BllAZlL<br />
The broad-nosed caiman is an endanqered Erazilian crocodilian. lts skin is<br />
considered bettet fot manufacturing goods th€n that ot glin4 crocodilus<br />
becar.rse it has le:s osteoderms in the belly skin. This is causing an increase in the<br />
level of inlerest in its fatming itr southetn and southeastern Btazil.<br />
The remnant populations are possibly depleted and fragmented by habitEt<br />
deekuction. The State of S5o Paulo had only 8.62 of its original native<br />
ecossystems until 1973, and will possibly have around 3.02 until the year 2080<br />
f/lCTOFl.1S75l, There are some preliminaty observations on the apparent<br />
colonization of broad-nosed caiman in environments such as small dams and<br />
decanting ponds of indushial ot human drainage IVERDADE & LAVORENTI,<br />
19901. There ate also some reports about the appearance of animals in suburban<br />
areas. even in big cities like Sdo Paulo end Fio de Janeito,<br />
The lack of information about the actual dishibution and possible nesting<br />
sites of these remnant tropulations maRes it diflicult to start a progtam on<br />
populational self reeovering based on the collection of eggs in the wild. ot<br />
ranching- like is being carryed out with success by Laniera [1990 and l991] in<br />
Santa Fe. Arqehtina. On the othe. hdnd. broad-nosed caiman has been a very<br />
common native strecies in Braailian zoos. although fiequently not consideted of<br />
greal importance. Nevettheless, trocradays. any plogrom of recovering.<br />
reintroducing and farminq. should start with a captiva propdgation ptogtam based<br />
on the real existing eaptive colony inZoos, research cenlers and other institutions.
220<br />
Materials t Methods<br />
We based our study on the Feptile Censuses of Etaziliatr Society of Zoos<br />
from 1984 to 1 991 , the Flegional Suldbook ol the hroad-nr-lsed caimon / 1 991 . and<br />
on direct consultalion lo lhe Erazilian Zaos staff.<br />
Resulls & Discussions<br />
The Fleptilian Census / 1991 by Bra:ilian 5 ociety oi Zoos reported 331<br />
broad-nosed caimans distributed in Zoos, research cerrters nnd othel ilstilutions.<br />
The captive colony hos been incteaging in the last yeat! [Fig. ll. Hoh,et/er, thls<br />
expdnsion is basically drre lo wild-caught animalx instead ol qoFtive'barn DnEs.<br />
The Flegional 5tudbook of this species repotted 183 animals spread in 19<br />
instituti€n$ in 1391- Around 40?; Df lhese animals were captive born, althouglr the<br />
r:olony of flZBAS .,r ESALQ .,'Univereity ol 55o Faulo. the bigge:.t in BtEail,<br />
FrEsenled a rdte ol 902.<br />
The sex r€lio of the Studbook colont'is apptoxrmatellg 6 moles,' 3lemales /<br />
2 indetermined. The teal numbets ate: 93 males.47 femeles and 37 itrdetermined.<br />
Some seriing mistakes moy happen, althaugh thE Z€'os staffs do not ccnsider<br />
sexing ':rocodilians a difficult tdsk. T raretrtg-two<br />
[44.7?] of the females are<br />
apparently adults. but just thtee bred suecesfully in the reproduclive perio'J of 139D<br />
i 13Sl and pnssibly iust one in the last tepraduElive treriod. Ies'rlting in 36<br />
hair-hlings in .l931 snd lusl 13 in 1992.<br />
9BvBn institutic,ns crf nineteen included in the 9tudbook [36.821 have<br />
reported nestinq al least once in itre la$t yeds, but iust 57.12 of the reForted trests<br />
were suceeifull, witlr a low nrean of 7 hatchlings per nBst. Ianging flom 1 to 31 in a<br />
medr, flulch :ize of 33 eggs Per nest.<br />
Only five institutions [28.3i;l sy:tematically m:rk l]reir arrimals individuallvand<br />
eight [42.lZl present some difiiculty in identilyinq Btazili€n cloDodilians.<br />
Age-pyramid of the Sludboak calonJr is completely btoken-r.tp- Thete is a<br />
great demand al youngs to enlarge lhe age-trtramid base [Fiq. :1.
221<br />
taplive ptopagation of br.-rdd-nosed caiman in Bt:iil nray be cun:idered<br />
insipient, altt'rough it is a relatively cornn otr :pecies in Btazilian Zoos Horryever a<br />
fe,ar zoas have alread-f' reported suocesfull reproduDtic'ns. Eqg incubalic,n seems to<br />
be the mort urgenl techniqu,e lo be managed to aviid loss of embryos or even<br />
v,'flsle ':iuh:l'res drrtin,f irrcubation Fretiod inta lhr, rresl<br />
The rnstitutions should n-|ark animals individual!' and certify tl'remsel'res<br />
6baut lhe sEeEies taxrrnorrri': identiiicat|on to al'oid l'-res ol data ahout tlietr<br />
ciJlLlnies.<br />
The rnarnten;..r-,i:e trl Fraziftau F'apulntion: af btoadlo:'ed cairnan in A'tex I<br />
of IITES is ulrri,::t importent beoause oi the lollc,wirrg reasons. poor captive<br />
FroEaqatir,n, deslruction of habitai!- illegnl l-'untinq FrBssule- and the lack !f<br />
irriormaliorr r-rn {.+ild pop'rlations.<br />
lBAh4A - Erazitiarr rlrildlife Aqericy is starting tn liberatF troad-nosed *ainran<br />
farms ior commetcial Furpr,-;e: lt miqht hove beneficial con*equences fc't the<br />
rFeDiFs r:.rn:retvalion. Ne\/erthelee!, lhe incleaslug interest of potencial fatmers<br />
and the FrEsant impo:,sibility af tanching srrcces: rn y resull in arl immBdi€te<br />
depletion .-,f the .emnarit Fr-rpulatiorr* lhreugh the captule af '.^Iild .snarnals ta<br />
assembly captive breedir-rg qroups in tl're fatrns. To avoid.luch pressure on r"rlld<br />
pc'puldtiens, captive-horn anin.rals should he u-',Ed instead c,f ','.tild-born onas. T he<br />
latter 'rould only be captured dnd tlansferted to fetms when they ore in ptoblematic<br />
situ.rtiBn whi'rh mag represent tiskt tc, thts survival of the.inimal$. lo l]umarrs or<br />
tivestock (VEFDADE & SAI'ITlAGO. 1 5Slil.<br />
Acknowledgements<br />
Furrdo Murrdral para a Natr-rle?i 'WV/F. Proeess No. E64ll-032.<br />
FundagE:' de Estudas AgrErios "Luiz de Oueitoz" - FEALQ<br />
Instituto de Fe,;quiras e Estudas Fl':restais - IFEF
.<br />
222<br />
Literdture Cited<br />
ilenso de animais- 1385. Sociedade de Zool6gicos do Erasil. Ssrocaba. Brazil. No<br />
pagandted.<br />
Censo de oninrais. 1 386/1 987. Sociedade de Zorrldgrcos do Brasil- 5 orocsba.<br />
Erazil. Nr: paginated.<br />
[enso de Feptais. 1 9l]S Sociedade di ZoolAgicos do Braril. Sorocaba- Era:il.<br />
65o.<br />
fenso de €nimais. 1 990. Sociedade de Zool6gicos dr: Brasil. Sorocaba. Erazil.<br />
94p.<br />
Censo de Animais. 1 991. Sociedade de Zool6gicos do Frasil. Sorocaba. Brazil.<br />
93o.<br />
Laniera.A. 1990. A program af rnonitoring and re+overing of caiman's populatior in<br />
A,rgentints with the airn o[ management. p.l-5. In: Proc. 1oth Wo4,:. Meet. Croc.<br />
Spec. 6roup. lUtrN'The\dorld Conservation Union. Gland. Switzerland. Vr:|. 2.<br />
345o.<br />
. 1931. A program of manitoring ar'd recovering of wild rrr*,puloatiDns ol<br />
c€imane in Ar:lantin,: r"+ith the aim of manalement. Fragress report 1:t Beg. Wr:rk.<br />
ldeet. Crou:. Spec. <strong>Group</strong>. Santa h4arta. Colombia, T-1 1 November'139'1. 7p.<br />
Fegional Studbook of the broad-nosed caiman lCaiman latirqstrisl. 19S1 . ESALQ<br />
/ Unrversrty ol SEo Paulo. Pitacicaba. Btazil. 33p.<br />
Verdade. L.M. & Santiaqo. M.E.B [Eds.]. 193ff. .Anais do I Workshop sobre<br />
ConservagHo e M aneio do iacare.de-papo-amarelo lCaimin lrtircrlr$]. ESALQ /<br />
University ol SEo Paulo, Firacicaba. Erazil. 34p.
223<br />
Verdade. L t*l & Lavorenti. A. 1 990. Preliminary note$ Dn the status and<br />
conservation of ttimtg blitO$rlf in the State of 56o Paulo. Brazil directions of<br />
.iaFtive breeding. reintroduction and management ptollram. p.231-237. lrr: Ptoc.<br />
1Oth Work. l.,leet. Crurr. Spec. <strong>Group</strong>, IUCN - TheWorld Conservation Union.<br />
Gland. 5wileerland Vsl. 2 345F.<br />
Victor. M A,M. 1375. A devastagEo<br />
llotestal soc. Bras. Silviculiura.<br />
55o Patdo,<br />
BrE:il 4Bo
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Figqre 2: Ag6.pyramid ol b.oad-noe€d c.iman captiv€ colo.iy in Brazil<br />
(knovfi aged animats)<br />
As"<br />
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PS: Exlractod fom the broad-nos6d caiman Rsgional Studbook,/ 1991<br />
225
226<br />
Prelimina.y Not€s on N€sting Biology oI the Broad-nosed Caiman<br />
(Caiman hlilgtlrrt) in Seo Paulo. Bra-zil<br />
l-uciano M. Verdade. A. Lavor€nri. F. Michelotti, M.C. Rangel. L- Cullen &<br />
M M. L.rnandes<br />
CIZBAS / ESALQ<br />
U nivLlfsity ol S5o Paulo<br />
Caixa Postal Og<br />
Piracrcaba 134OO SP BRAZIL
227<br />
Preliminary notes on nesting Eiolog_v of ihe broad-nosed caiman [Laie0a0<br />
iilitr*tnrl in S5o Paulo, Brazil<br />
Luciarro f.4. Verdede. A. Lavorenti. F Miche!:tli, l'4.C. Fanqel. L fullen & M.M.<br />
Ern.:nder<br />
l.lzF.qi /' F5AL[ ,' lJrri'retgty of !5,: Paulc,<br />
llr. P t-l:l ! ll40D Firacicaba :lP FFAZIL<br />
lnlroductiqn<br />
Tl'lere arE iiar19 !eFrrft! ,ll rucc,estrill cror:odilian,: cap,tirre F opsgahon<br />
Eroed'nored caiman specifically has also been reporied to have been succesfull,|,<br />
reprodu*ed in coplivitj,r {Ractra e I il" a & Zuquim Antas, I901 ; Arronimous. | 988;<br />
Widhoher et al.. 1S8E: L.arriera. 1 938 end t/erdndE i', Lav'rrenli. 1 99L1J However.<br />
its large dlstrihution zDne dFmand! rr,lre Infornr.iticn on its nesling BiolLrgf to<br />
inDrEsse ils iapli\.e prapeg3tinr'.<br />
l'{aterials & Methods<br />
l,rje reported 17 nest.: ,-rf hruad-r-r'.,secl cainran in Laptivity an SaLr PnrdB Sl€t*<br />
lrorir 19EF; !o 1ils?. Nine r-,f there nesls t.,ere located ir' the facilities oi ESALQ /<br />
Unilersity ol S5o Par-rlo, six inioc,s. ond trnr':, in other irrstilutinrts.
228<br />
Besults & Discussion<br />
The nunrber of rep,rrted nells can be considered s.ndll Dompared to studies<br />
conducted r,rith Fther crocodilians [r't/ilkirrssn. 1 984 and Cattroneau & Chabteck.<br />
19901. However. this paper represents thr maiDr repnrt for this speries in Erazil.<br />
Generally, the nest materials followed ttre mound-nest pattean desDribed ir.)<br />
the literdture fGreer" 1970; Martin. 1977 and Ferguson, |985]. The nest sizes<br />
presented in Table- 1shor"" thdt there is no signiiicant diftptence belween nests<br />
that ha\ne soil ac a content, and thase tlrat do not. As a result, t^,e cnn infer lhat<br />
nests are built up nith a rel€tively c'trnst€nt size. 5o . at least in captivity.. can te<br />
used ordy lo complete the "normal" nest size. The fact that soil as a content wa$<br />
found only where there wos apparently not enough amounl of lear/es and debris<br />
reems to corrobcrate this ided. Laniera [personal communication] has been linding<br />
two basic nesting sites in the Argentinean "pampds": savanna-nest and fotestnBSt.<br />
The latter ulually presents soil Es one of the maiil contents. ptobably also due<br />
lo the smoller otler of leaves and debris on the forest oround lhdn on lhe savannd<br />
ground-<br />
Table 2 shows sonre other reeults on nesting Biology. The nests wete<br />
located around 2 meters far fiom the wdter pond in average. ranging lrom 0 to 7<br />
meters. The incubation period ranged from 73 to 33 da_vs [77.5 in average). The<br />
clutch size ranged fronr 1S to 49 [33 in average] with a relativelg low rate ol alive<br />
hatehlings per rrest: 7 33 ranging from 0 io 31. The mean egg weight was 70.89 q<br />
each. ranging fiom 60 to 82.2 q. The eggs maior diameier measured 6.73 cn'r.<br />
ranging fiom 6 to 7.5 cm, u+hile the minar diameter measured 4-28 cm. ranging frcm<br />
3.4 to 4.5 cm. The hatchlings weiqhted 47.61 g in average, rangir'g fiom 3S to 63q<br />
each, and measured 24.65 cm total length" rarrqing from 21.3 to 27 cm. The dams<br />
weiqhted ?9.52 kq in average- ranging from 15 to 59.7 kg. ar'd measured 88.83cm<br />
mB.rn snout-vent length, ranging lrom 7tl to 110 cm. The sires weighted 37.95 kg<br />
in auerage. ranging irom 30 to 64 kg and measured 95.04 cff. rfiean snout-vent<br />
length- ranging from 90 to 109 cm.
229<br />
The nesting Feriod slarted in late flctober and linished in mid Febru€ry,,ith d<br />
pick in Jarruaru. while the hotchinq period :torted in eady Febnrary and ended in<br />
middle.April. with a peak in March [Fig. .l l.<br />
Almost all of the femeles i94.4?jl esibited maternal behavior durng<br />
incubalion period. bul contr€ry to the observations ,rf \,r/idholeer et al. [j986l. no<br />
m.:le had teen seen to e:
230<br />
Litetatute Cited<br />
Anonrmous. 19€6. Nasoeu a Fnmoi.t nirthada d€ iacare do CIZBAS' Jornal
i act€ I N€:t sEes<br />
Heighl (cm)<br />
Longlh (cm)<br />
Widlh (cm)<br />
Chi-rquar6 Test:<br />
Heiehr<br />
Longth<br />
\A,id|}r<br />
(samples A & B)<br />
49_2<br />
134.2<br />
103.4<br />
2<br />
)<<br />
1.541<br />
2.94S<br />
415.18<br />
30.56:<br />
42,55<br />
Nests wilh loil<br />
(sa.nple A)<br />
-m)a<br />
> 2t)'"<br />
> 5.1.<br />
42<br />
1tg<br />
104<br />
10.65.1<br />
34.63:i<br />
17.41:<br />
'rabb 2: Nestihg behavior ol broad-nosod caiman in captMiy in Sao Paulo State, Brazil<br />
(P€.riod l9a5 - 199a1<br />
Distanc€ kom th6 wale. (m)<br />
Incubalioh p€riod (daF)<br />
No. ol69gs p€r nest<br />
Siza ol €ggs - lsnglh (cm)<br />
- width (crn)<br />
\,v€ighl ol 6qgs (g)<br />
No. ol hatchling3 p6r nest<br />
Sk€ ol halchlings<br />
Worght ot hatchlings (g)<br />
Wgighl ol dams (kg)<br />
Woight ol sires (kg)<br />
Snoutvenl l6hg h ol dams (crn)<br />
Qno!!y9ll|lP!9th 9!_s'I93 G!!L I<br />
N: Sample siz6<br />
sd: Standard davialion<br />
CV : Coslid€nl ol varielion<br />
231<br />
I N6sta wilhoul 3oil<br />
:r (samPle B)<br />
s4.3<br />
145.7<br />
102.9<br />
cv% m4or N<br />
39.59<br />
27,41<br />
56,Oi<br />
7 | 16 n6sts<br />
77,5 3.Ol I 3.Aa<br />
9:] | 90 eggs<br />
3:| 10.63 | 3?.2 1a 49 | 12 ^e3t3<br />
4,?A o.2 | 4,54 3.4 4,5 | 123 6gss<br />
6.73 o.3 4.59 6 7,s l 123 osgc<br />
7(),49 5,64 7.95 60 42.2 | 156 69gs<br />
7,33 1l 14S.$) I 31 | 12 nesis<br />
2{,5s I 1,15 '1.66 21.S 27 | 50 hatch.<br />
47.6r I Lr8 17.14 36 63 | 50 hatch.<br />
29.52 | 10.61 35.92 1s I 59,7 | 15 damg<br />
37.S{' I I o.o4 26.44 sol 64 | 15 dam6<br />
80.33 | e,32 11,52 701 110lt3.ires<br />
t__s.7s I_ 9,05 |_.sO l_ _.-l_q I 13 3ir€s<br />
_._ _gs:::q!_
o<br />
6<br />
o<br />
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8o<br />
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IP<br />
(n ..<br />
o>\<br />
EE<br />
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gE<br />
EE<br />
o.'f<br />
s3<br />
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EE<br />
so<br />
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(UE<br />
?6<br />
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at, =<br />
2E<br />
t'j<br />
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.9<br />
lI-<br />
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t!<br />
9.-<br />
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ri<br />
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:9<br />
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oz<br />
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ct<br />
.ll o<br />
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(r<br />
@<br />
lrJ<br />
tt<br />
z<br />
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F<br />
o<br />
o<br />
ttJ<br />
CD<br />
E<br />
o G<br />
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f I<br />
E'<br />
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at<br />
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c<br />
o
CROCODILE MANAGEMENT AND RESEARCII<br />
IN THE NORTHERN TERRITORY: 1990-92.<br />
Grahame J.W. Webb, S. Charlie Mruolis, Breta Otlef<br />
and Andrew Heywardl<br />
G. Webb hy. Limiled, P.O. Box 38151, Winnellie, N.T.0821;<br />
Conservation Commission of the Northem Territory, P.O. Box 496,<br />
Palmersron, N.T. 0831; and, *Modical School, University of Adelaide, G.P.O. Box<br />
498, Adclaidc, S.A. 5001, Australia<br />
The central a;m of this paper is to summarise thc progrcss that has becn<br />
made with crocodilo research and managcment in the Northern Terrir.ory, in<br />
the last 2 years (April 1990 to July 1992). [n this regard, it complcmcnls the<br />
previous three updates presentcd at successive Crocodilc <strong>Specialist</strong> Croup<br />
(CSG) meetings t1986, 1988, 1990 (Manolis and Wcbb 1990; Webb 1989a: Wcbb<br />
et al. l990a\1. As before, it also includcs morc dctailcd results oI somc studrcs<br />
considered significant to CSG mcmbcrs.<br />
MANAGEMENT PROGRAMS<br />
Both spccies of crocodilian (Crocodltlus porosus and C. johnstoni) ir the<br />
Northem Territory are on Appendix Il of CITES. Croco.ltlus johnstoni has<br />
always becn on Appendix II, whereas C.porosus was lransfcrred from<br />
Appendix I to Appendix II, for the purposes of ranchhg, in l9tl5 (Webb e, al.<br />
1984).<br />
Within Australia, wildlife conservation and managcment is a<br />
State,/Torritory responsibiliry, bu! the export and import of wildlife and<br />
products derived from thcm, into or out of Australia, is a Commonwealth<br />
responsibility. It is controlled by lhe Australian Customs Sgrvice and lhe<br />
Australian National Parks and Wildlifc Service (ANPWS), according to rhe<br />
provisions of the Wildlife Protection (Regulation of Exports and Imnorls) Act<br />
l9]la. This Act makes export and imporl of species listed in CITES appcndiccs<br />
subjcct to the Fcderal Minister approving Managemen! Programs for thosc<br />
specics.<br />
The currcni Norlhcrn Tcritory <strong>Crocodile</strong> Management Program, approved<br />
in January 1990 (CCNT 1989), addresses the management of both spccies of<br />
crocodile and is currenl lor 5 years. h describes the ranching program for C.<br />
polosri, which involves a widespread egg harvest and the limited taking of<br />
older stock for farming purposcs. It also describes the program lor C.<br />
johnstoni, which involvcs bolh cgg and hatchling harvcsts. I1 details<br />
maximum levels of harvest from the wild of all stock, for all purposes,<br />
including animals ronrovcd as "problem" crocodilcs and animals usod for<br />
rcscarch. It also contains a protocol for altering those limits from year to<br />
year. Currcnl (1992) annual harvcsl limits are:<br />
Viable Eggs<br />
Hatchlings<br />
Juvcnilcs<br />
Adults<br />
C. porosus<br />
15,000<br />
400<br />
500<br />
250<br />
C . johnstoni<br />
4000<br />
6000<br />
1000<br />
200
234<br />
The Managemcnt Program also details thc moniloring programs caricd<br />
out on the wild populations, and the manner in which captive stocks on thc<br />
six registercd crocodile farms are bo[h regulatcd and monirorcd. Under thc<br />
auspices of tho Managoment Program, consideration has now bccn given rc a<br />
"Crocodilc Industry Strategy". It will lead to increased involvement in<br />
crocodile farming by both thc Dcparrment of Primary Indusrry and Fishcrics<br />
and the Dcpartment of Industrics and Devclopmcnt.<br />
MONITORING . PROBLEM CROCODILES<br />
Since April 1990, there has been onc fatal attack (on Groo!€ Eylandt) a d<br />
one serious but non-fatal attack in thc Daly Rivcr (Fig. 1; a C. porosts entcred<br />
a tcnt at night and atlacked a woman). A number of minor incidenls havc<br />
bccn reportcd, particularly with fishermen, and somc have received mcdia<br />
attention. Ovcrall, the rcsponse from rhe public has bcen objective and<br />
rational, allhough calls for culling continue. Thc cconomic valuc of<br />
crocodiles in the Norlhcrn Territory is thc single most importanr inccntivc<br />
Ior the public to accept the ncgative side of having largc wild populations oI<br />
C.porosus throughout thc coastal wctlands.<br />
As pan of the public safcty campaign within thc Northem Territory,<br />
"problem" crocodiles are removed from the wild and assigncd to crocodilc<br />
farms. Such animals are broadly defined as "those wilhin scttled areas or<br />
areas of intcnse recreational use wherg public safety is a prirne<br />
considcration and those individuals which affect a land-use activity (c.a.<br />
takinS stock on pastoral land). In intensive conlact arcas such as Darwin<br />
Harbour and Cove recreational bcaches, any crocodilc, rcgardless of speeics<br />
or size, constitutes a 'problcm"' (CCNT 1989).<br />
During 1990 and 1991,457 problcm C.2orosas were deatr wilh by thc<br />
Conscrvation Commission (Tablc 1). Of these, 431 (94.3Eo) were distributed to<br />
crocodile farms, 19 (4.2o/a) wcrc rclocared in rhc wild, 6 (1.370) dicd al capturc<br />
^nd 1
S- - ^r\^<br />
A "L
236<br />
MONITORING - HARVESTS<br />
Crocotl!lus johnsrori Harvests<br />
Egg and hatchling harvesls for 1990 and 1991 are summariscd in Table 2.<br />
Altogether, 3390 eggs wcre collected, of which 3024 conraincd live embryos<br />
and were considered viable (89.2o/a\: the remainder were either infertile<br />
(4.2Vo) ot dead prior to collection (6.67o). A proportion of the viable cggs<br />
Ioc^red
disturbancc to all unwary crocodiles: thc pcrccntage of the total populalron<br />
sighted afte( thc harvcsr may wcll have becn lowcr than rhe percenlagc<br />
sishtcd beforc lhe harvest.<br />
Crocodtlus polrrxr Dgg Harvest<br />
Thc resulls of C. porosus egg harvesting are on Tablc 4. Crocodylus porosus<br />
have a prolonged ncsting pcriod (Novembcr to May) that coincides with thc<br />
wel season. Largc numbers of cggs arc flooded before collection, and in somc<br />
locations where nesls are conslructcd in the open, the eggs overheat (Wcbb<br />
and Cooper-Preston 1989). Thcrc is also a significant relationship bctwecn<br />
rhe exlent of mo(ality in rhe ficld and thc cxlent of morrality after collcction<br />
lduring arlificjal incubarion;Wcbb (1989b)1. Thus allhough our assessmcnls<br />
of "viablc" eggs are based on live embryos at the timc of collccrion, many of<br />
those embryos arc alrcady compromised. Variation in thc numbcrs of cggs<br />
harvcslcd each ycar (Table 4) rellects annual vadation in ncsting cfforl<br />
(webb et al. 1990a). and also variation in ha est areas. Annual variation rn<br />
nesting effort for some areas is summariscd on Tablc 5.<br />
Tablc 4. Numben of C. porosus eggs haryestcd lrom the wild with an<br />
asscssment of viabilily (containinS live embryos at the time of<br />
collection), and lhe percentage of viable eggs. thal produccd viablc<br />
hatchlinss.<br />
Scason Total Eggs<br />
Col lccred<br />
r98618'1<br />
1987/8 8<br />
198 8/89<br />
1989t90<br />
1990/91<br />
4401<br />
5300<br />
649',7<br />
12,010<br />
9212<br />
Vo Yiable<br />
Egg s<br />
62.7<br />
64.3<br />
67.2<br />
't 4.5<br />
59.6<br />
'/o Viablc<br />
Halchlings<br />
80.1<br />
82.7<br />
u4.5<br />
85.5<br />
'77.4<br />
Table 5. Numbers of C. porosus nesls localcd (cxcluding false nests) and total<br />
cggs collccted, in threc areas where collcclion elfort has bcen nore<br />
or less constanl In mosl ycars. * indicare where effort was rcduccd.<br />
Season Adclaidc River<br />
(mainslream)<br />
Nests Eggs<br />
1983t84<br />
1984185<br />
1985/86<br />
r986/8'7<br />
l9 87/8 8<br />
1988/89<br />
1989190<br />
199019r<br />
t99t 192<br />
2l<br />
37<br />
39<br />
56<br />
27<br />
45<br />
1025<br />
695<br />
859<br />
1272<br />
1'756<br />
2250<br />
tt71<br />
| 547<br />
Adelaide River<br />
(Mclacca Swamp)<br />
Nests Eggs<br />
28<br />
22<br />
22<br />
I2<br />
27<br />
ll<br />
618<br />
959<br />
934<br />
1002<br />
581<br />
1189<br />
1560<br />
622<br />
1327<br />
Finniss<br />
River<br />
Nests Eggs<br />
20<br />
23<br />
36<br />
4l<br />
4l<br />
-)l<br />
64<br />
960<br />
105't<br />
tl72<br />
r443<br />
t936<br />
1U48<br />
3179<br />
237
238<br />
Tolal Ilarvest Limits<br />
Total harvests of both C. johnstoni and C. porosus, for all purposes, during<br />
the tenure of the current Management Program (CCNT 1989) arc sunlmariscd<br />
in Table 6.<br />
Tablc 6. Numbers of C. johnstoni atrd C. porosus c8gs, harchlings, juvcnitcs<br />
and adults taken from the wild during the last two years, with<br />
harvest limits applicable in thosc years.<br />
Species Limit Harvestcd<br />
C. johnstoni<br />
C. johnstoni<br />
C. johnstoni<br />
C. porosus<br />
C. porosus<br />
C. porosus<br />
C. porosus<br />
1990<br />
t991<br />
1990<br />
1991<br />
1990<br />
1991<br />
1990<br />
199r<br />
1990<br />
1991<br />
1990<br />
1991<br />
r990<br />
1991<br />
1990<br />
t99r<br />
Viablc Eggs<br />
Viablc Eggs<br />
Harchlings<br />
Halchlings<br />
Juvcnilcs<br />
Juvcnilcs<br />
Adults<br />
Adults<br />
Viablc ESgs<br />
Viable EgSs<br />
Hatchlings<br />
Hatchlings<br />
Juvcniles<br />
Juvenilcs<br />
Adu I ts<br />
A du l1s<br />
4000<br />
4000<br />
6000<br />
6000<br />
1000<br />
1000<br />
200<br />
200<br />
10,000<br />
10,000<br />
400<br />
400<br />
400<br />
400<br />
200<br />
200<br />
MONITORING . WILD POPULATIONS<br />
C rocod!lus johns totti<br />
207 |<br />
953<br />
1621<br />
45't9<br />
2t)<br />
187<br />
0<br />
2<br />
{i 953<br />
5491<br />
l3<br />
l0<br />
120<br />
t62<br />
Annual spotlighr and helicoplcr survcys arc conductcd in rcprcscnrarivc<br />
samples of C.johnstoni habiaat as pan of a lon8-lcrrn moniroring progranr.<br />
The Daly River (Fig. l) is suneycd annually, and is one of thc maiD rivcrs<br />
from which C.johnstoni harchlings arc harvested. It provides a good sysrcm<br />
lor cvaluating tho gencral impact of harvcsting. For survcying, ihc river is<br />
subdivided into 9 segmcnts scparated by rockbars and waterfalls (total<br />
distance = 196.3 km). Hatchling and egg harvests are restricted to lhc<br />
upslream 91.9 km and the downstream 6{1.5 km; the ccntral area of 35.9 km<br />
has been surveycd but not harvested.<br />
70<br />
63
E<br />
3400<br />
32 00<br />
3000<br />
2800<br />
.s,<br />
'6<br />
6<br />
F 220<br />
24<br />
2000<br />
1800<br />
1600<br />
1400<br />
1982 1983 1984 1985 1S86 1987 1S88 1S89 1990 1991 1992<br />
Year<br />
Figurc 2. Toaal numbcrsof<br />
C. john.rtori counled by spollight in thc annual<br />
survcys of thc Daly River betwecn 1983 and 1991.<br />
Thc population of C.johnstoni in thc Daly Rivcr has continued to incrcasc<br />
(Fig. 2) regardless of thc harvcst of 866 eggs and 15,655 ha!chlings betwccn<br />
1982 and 1991 (Table 7). The natural logarithm of numbcft sighlcd in ihc<br />
spotlight survcys was rcgrcsscd against ycar to estimate r, the exponential<br />
rate of population incrcasc (thc rcgrcssion line slope)(Caughley 1980). To<br />
express r as a mcan pcrccnlaSe changc, the exponent of r is uscd<br />
lpcrcenlage cbange = fer - l).1001.<br />
Tablc 7. Numbcrs of C.johnstoni hatchlings and eggs harvcstcd from rhe<br />
Daly Rivcr bcrwccn 1982 and 1991.<br />
t982<br />
198 3<br />
19 84<br />
19 85<br />
1986<br />
r98'.1<br />
1988<br />
19 89<br />
1990<br />
199 r<br />
Tolal<br />
Hatchlings Eggs<br />
1299<br />
825<br />
13t7<br />
0<br />
928<br />
229'/<br />
15 60<br />
2'.700<br />
t223<br />
35 06<br />
15,655<br />
548<br />
318<br />
0<br />
0<br />
0<br />
0<br />
0<br />
866<br />
239
uo<br />
The cxponential rate of population increasc for all sightings in all areas<br />
of the Daly River (Tablo 8) was 0.056 :r 0.020 (p = 0.024), indicaring an avcragc<br />
increase of 5.8qa per ycar ovcr the period 1983 to 1991.<br />
Within thc 9 individual survey scctions (2 non-harvested and 7<br />
harvested) r rcached significance in only two (l non-harvestcd and l<br />
harvested)(Table 8). In both cascs the change was positive, indicarinS<br />
annual average incrcases of 9.37, (Section 2; non-harvested) and 2'l.IVo<br />
(Section 3; harvested). There is almost cenainly interchangg of animals<br />
betwecn the harvestcd and non-harvested populations, which confounds<br />
any dclailcd analysis.<br />
Table 8. Annual spotlighl counts in 7 harveslcd and 2 non-harvcslcd<br />
scctions of the Daly River. r = tho exponential ratc of increasc; SE=<br />
standard error; P = the probability that r is duo to chance. Totals lbr<br />
1983 and 1984 arc based on cslimatcs for the 3 sc[mcnls not<br />
su rv cycd.<br />
Section<br />
km<br />
198 3<br />
1984<br />
l9 85<br />
19 86<br />
r987<br />
r988<br />
l9 89<br />
r990<br />
1991<br />
r<br />
SE<br />
P<br />
Non-harvested<br />
t23<br />
14.3 2r.6 31.0<br />
I7I<br />
240 197<br />
292 24'7<br />
203 346<br />
220 331<br />
303 470<br />
195 380<br />
196 313<br />
201 442<br />
-0.01 0.09<br />
0.03 0.03<br />
0.82 0.03<br />
- 216<br />
70 233<br />
109 r9'7<br />
r12 199<br />
229 303<br />
3 83 422<br />
266 275<br />
398 262<br />
312 276<br />
0.2 4 0.0 5<br />
0.0-5 0.03<br />
per ycar) was posilive and higher than the ratc from rhc non_harvcsted<br />
rivers (-0.011 ! O.041: -1.1o/a<br />
pcr year) which was irself highly variabtc.<br />
Tablc 9. Thc si/e struclurc ol C. johnstoni si*htcd in sDotli{hrsurvcys<br />
in lhe<br />
Daly Rivcr bcrwccn t98J and t9vl. Fcrccnragci rcfir only to non,<br />
hatchlings whose size could bc estimated. Haivests in any onc ycar<br />
(Table 8) arc conducrcd afrer thc survcvs.<br />
Year ToIal<br />
Count<br />
1983<br />
1984<br />
r985<br />
19 86<br />
1987<br />
1988<br />
198 9<br />
1990<br />
1991<br />
1433<br />
1682<br />
1843<br />
2125<br />
2364<br />
318ri<br />
2350<br />
2228<br />
2485<br />
Eyes >2' 4-6' 6-8' >8'<br />
Only (E" ) (E" \ (v")<br />
706<br />
889<br />
1495<br />
t402<br />
1510<br />
185 8<br />
1512<br />
143 8<br />
1448<br />
105<br />
91<br />
64<br />
183<br />
50<br />
'71<br />
8't<br />
83<br />
99<br />
81.0<br />
82.5<br />
45.4<br />
69.3<br />
dJ.)<br />
75.0<br />
92.4<br />
7',7 .8<br />
'79.7<br />
t 6.4<br />
r J.5<br />
43.0<br />
26.9<br />
14.3<br />
21 .8<br />
7.1<br />
l9.t<br />
t7.6<br />
1.8<br />
2.0<br />
3.7<br />
2.2<br />
3.1<br />
0.5<br />
3.0<br />
(../a )<br />
0.8<br />
0.0<br />
0.4<br />
0.2<br />
0.0<br />
tJ.2<br />
0.0<br />
0.1<br />
0.1<br />
Table 10. Exponcntial ratcs of incrcase (r) lor C. johnstoni in arcas surueycd<br />
by helicoptcr annually. In survcys wherc no crocodilcs wcr,<br />
spotred in a parlicular arcr. in any onc yerr, t sighling has bccn<br />
added so rhar a log (ln) value could bc compurcd. *-inOiiates :,<br />
signilicant rcgrcssion relationship.<br />
Rivcr Survcy Area N Years r<br />
Dal y<br />
Daly<br />
Daly<br />
Daly<br />
Daly<br />
Daly<br />
Daly<br />
D aly<br />
Baincs<br />
Baines<br />
Baines<br />
Baines<br />
Baines<br />
Baincs<br />
Bainss<br />
Baincs<br />
Wickham<br />
Wickham<br />
Wickhan1<br />
Wickham<br />
Downstrcam tidal<br />
Crossing-Isl<br />
and<br />
Fish-Witch Wa;<br />
Wilch Wai-Bccboom<br />
Bceboom-Rookbar<br />
Rockbar-Oolloo<br />
Oolloo-us rapids<br />
Bullira<br />
ds East Baincs Pool<br />
East Baines Pool<br />
Homesread Pool<br />
TH Holc<br />
us East Baincs Pool A<br />
us East Baines Pool B<br />
us East Baincs Pool C<br />
Homcstcad Holc<br />
Humbcrt Rivcr Pool<br />
Humbcrt Slation<br />
lrrigalion Holc<br />
7<br />
'1<br />
7<br />
'l<br />
7<br />
'7<br />
7<br />
't<br />
7<br />
7<br />
6<br />
7<br />
5<br />
7<br />
,7<br />
1<br />
7<br />
7<br />
,7<br />
1985 91<br />
1985-91<br />
1985 91<br />
l9lr 5 -9 I<br />
l9 85,91<br />
1985-91<br />
1985,9 r<br />
198 5-9 I<br />
19 8 7,91<br />
1985-91<br />
1985 -91<br />
198 5-9 1<br />
l985-9r<br />
1985-91<br />
l9 8-5 -91<br />
1985-91<br />
r985-91<br />
1985-91<br />
1985-91<br />
1985 9l<br />
0.2 6l<br />
0.250<br />
0.288<br />
o.23'I<br />
0.252<br />
0.369<br />
0.390<br />
0.405<br />
0.3 l1l<br />
0.196<br />
0.t25<br />
o.126<br />
0.154<br />
0.450<br />
o.044<br />
0.t61<br />
0.5 3l.l<br />
0.339<br />
0.251<br />
0.4 18<br />
0.03 *<br />
0.06<br />
0.2 8<br />
0.26<br />
0.50<br />
0.20<br />
0.25<br />
0.0 u<br />
0.81<br />
0.47<br />
(J.03 *<br />
0.10<br />
0.05 x<br />
0.01<br />
o.02<br />
0.00<br />
0.15<br />
0.04<br />
0.06<br />
0.01 *<br />
241
Tablc 10 continucd.<br />
River Survey Area N<br />
Wickham<br />
Wickham<br />
Wickham<br />
Victoria<br />
Victoria<br />
Victoria<br />
Victoria<br />
V icto ri a<br />
Victoria<br />
Victoria<br />
Victori a<br />
Mean all areas<br />
Stoncy's Crossing<br />
Vicroria/wickham Jn.<br />
Yarralin<br />
ds bridgc<br />
Jasper A<br />
Jasper B<br />
Old Vic. R. Crossing<br />
Pigeon Holc<br />
Policeman's Point<br />
Rockhole<br />
us bridgc<br />
7<br />
7<br />
7<br />
'l<br />
'l<br />
'l<br />
'7<br />
7<br />
7<br />
7<br />
7<br />
1985-91<br />
1985-91<br />
1985-91<br />
1985-91<br />
l9 85 -91<br />
r 9 85,91<br />
l9 85 -91<br />
1985-91<br />
1985-91<br />
1985-91<br />
1985,91<br />
0.257 0.3l<br />
0.503 0.0r<br />
0.491 0.04<br />
0.415 0.12<br />
0.202 0.16<br />
0.040 0.47<br />
0.551 0.03<br />
0.r99 0.13<br />
0.049 0.60<br />
0.162 0.10<br />
0.313 0.02<br />
0.282i<br />
0.026<br />
Tablc 11. Exponcrtial ratcs of incrcasc (r) for C. johnstoni in river syslcms<br />
spotlight survcyed rcgularly in the Norlhern Tcrrilory.<br />
a significant rcgression relalionship.<br />
surveyed; P= the ProbabilitY thal r<br />
significanl aI thc 5% level.<br />
* indicatcs<br />
N = number oI ycars<br />
is due 1o chancc; * = a result<br />
River Survey Arca N Years<br />
P<br />
Baines<br />
Kathcrine<br />
Mary<br />
Moyle<br />
Finniss<br />
Reynold s<br />
Mean Non-harvcslod<br />
West Baincs<br />
Dal y<br />
Finniss<br />
Mary<br />
Reynolds<br />
Reynolds<br />
Victoria<br />
Victoria<br />
Victoria<br />
Victoria<br />
Wickham<br />
Mean harvested<br />
Mcan All rivcrs<br />
East Baines Rivcr<br />
Katherine Gorge<br />
Downstream<br />
Moyle River<br />
Buffalo Holc<br />
Walcrholc<br />
TH Hole<br />
Daly Rivcr<br />
Finniss mainstream<br />
Ups tream<br />
Rcynolds mainstrcam<br />
Fish Canrp<br />
Downstrcam<br />
Mid dl c<br />
Upstream<br />
Pigcon Hole<br />
wickham<br />
3<br />
9<br />
5<br />
7 ,7<br />
6<br />
7<br />
9<br />
9<br />
6<br />
9<br />
8<br />
5<br />
7<br />
3<br />
J<br />
l1<br />
t7<br />
1982-86 -0.002<br />
1980-88 -0.084<br />
1984-88 -0.014<br />
1984-88 -0.025<br />
19tt4-90 0.176<br />
1984-90 -0.115<br />
,0.011 i 0.041<br />
o.97<br />
0.0 6<br />
0.8 8<br />
0.91<br />
0.02<br />
0.3 5<br />
1883-91 -0.01? 0.72<br />
1983-91 0.056 0.02<br />
1983-91 0.008 0.84<br />
l s84-89 0.048 0.40<br />
1983-91 0.041 0.59<br />
1984-91 0.016 0.77<br />
19112,86 0.154 0.1'l<br />
19{J2-88 0.094 0.15<br />
1983-86 0.159 0.i 6<br />
1982-91 0.041 0.12<br />
1982-87 0.070 0.36<br />
0.061 i 0.017<br />
0.036 t 0.019
The disparity bcrween lhc ratcs of increase indicatcd by helicooter and<br />
spotlight counts rcflccts in part the limitalions of hellcopicr couniing with<br />
C. johnstoni. A small proportion of thc total population is sighrcd, and in ftis<br />
case, it could be reflecting changes in thc largcr animals. Al!hough the<br />
dispariry is undcr investigation, ir is significant that both survey mcthods<br />
indicatc a positivc ratc of incrcase despite harvcsling.<br />
C rocod!Ius poro sus<br />
AswithC. johnstoni, monitoring of lhe C. porosus population involvcs<br />
surveys at two lcvels of rcsolution. Firstly, spotlight counts in selccted rivcrs<br />
aro car.ied out annually to monitor thc biological aspecls of continuing<br />
recovery (see 'Recovcry Trends in the Blyth-Cadcll Rivor System', berowl.<br />
Helicoptcr counts arc the method used to monitor the populalion as a wholc.<br />
Wilhin individual rivcrs subjccied to intcnse harvcsting of eggs, rhc<br />
population has conlinucd to increase dcspite harvcsring (Fig. 3). Significanl<br />
numbers of nests arc not detcctcd and local recruitnrsnr srill occurs (Fig. 4).<br />
The population size slructutc does not reflcc! a "missinq" cohort !hat could be<br />
expccted to inllucncc adulL numbcrs in thc futurc (Table l2).<br />
(,<br />
z<br />
-<br />
F<br />
r<br />
z<br />
o<br />
o<br />
c!<br />
f<br />
2<br />
900<br />
800<br />
7AO<br />
600<br />
500<br />
400<br />
300<br />
200<br />
1976 1978 1980 1982 1984 1986 1988 1990 1 992 1994<br />
YEAFI<br />
Figure 3. Annual spotlighi counts of non-hatchling C. porosus \n thc<br />
mainstream of the Adclaide Rivcr, Northern Territory (60 km east<br />
of Darwin). Numbers of cggs harvcsred from 1984/85 to t99llg2 Ne<br />
in Table 5; in 1983/84 525 cggs wcrc collectcd from thc mainsrrcam.<br />
"fo dale, 19,942 eggs havc been harvcslcd {rom the sysrcm since<br />
19 83.<br />
243
244<br />
o<br />
z<br />
-<br />
r<br />
E<br />
l<br />
z<br />
350<br />
300<br />
250<br />
200<br />
150<br />
100<br />
50<br />
0<br />
1976 1978 1980 1982 1 S84 1986 1 988 1 990 1 992 1 994<br />
YEAR<br />
Figure 4. Numbers of hatchlings sightcd during spotlight survcys ol lhc<br />
Adclaide River mainstreaDr (117.0 km). The line indicates thc pcriod<br />
in which cSgs have bccn harvcstcd (1983/84 to 1991192 wet<br />
scasons).<br />
Table 12. Size structurc of C. porosus sighted in spotlighr surveys in rhc<br />
Adelaidc River bctween 1977 and 1992. Percentagcs refcr only to<br />
non-hatchlings whose sizc could be estimated. Suftey results arc<br />
those nearcs! June in each ycar. * indicatcs years in which eggs<br />
were collected in the wcl scason bcforc a survey; between 1977 and<br />
1979 aninals grcatcr than 7'in length wcre recordod as ">?".<br />
t9'7',|<br />
19't8<br />
r9'79<br />
* 1984<br />
+1985<br />
*r986<br />
*1987<br />
*1988<br />
,N 19 89<br />
*1990<br />
*1991<br />
*t992<br />
Total Eyes<br />
Count On ly<br />
388<br />
387<br />
618<br />
582<br />
5'72<br />
?85<br />
151<br />
709<br />
936<br />
8'/ 6<br />
1082<br />
36<br />
33<br />
36<br />
144<br />
13't<br />
112<br />
130<br />
161<br />
168<br />
161<br />
4' 2-4'. 4-6' 6-8' 8-r0' >10'<br />
(E") (E > (q") (E") (8")<br />
48<br />
62<br />
80<br />
r37<br />
99<br />
2s9<br />
'76<br />
350<br />
85<br />
403<br />
36.1<br />
23.1<br />
36.5<br />
31.5<br />
40.1<br />
46.',7<br />
41 .8<br />
55.3<br />
43.9<br />
52.6<br />
51.0<br />
56.8<br />
28.9<br />
32.1<br />
30.5<br />
26.8<br />
22.0<br />
22.6<br />
16.1<br />
18.0<br />
2t.l<br />
-------- 11.3 ,-----<br />
_---____ 12.6 -,-,--<br />
--,-,-,- 20.1 ------<br />
21.8 10.4 2.3<br />
20.8<br />
r7.5<br />
r9.'7<br />
15.0<br />
9.7<br />
8.9<br />
5. {i<br />
1t.5<br />
5.8<br />
2.5<br />
1.0<br />
4.3<br />
17.8<br />
22.6<br />
14.0<br />
l1.0<br />
16.0<br />
'7.2<br />
3.5<br />
3.0<br />
5.4<br />
23.8 9.2 2.0<br />
Annual spotlight counl survcys wcrc carricd out in 8 rivcrs in both 1990<br />
and l99l (Table 13), the majority of which had cggs harvcstcd lrom them.<br />
The exponenlial ralc of incrcasc (r) was calculatcd for each major river<br />
scction. Thosc wilh a significant change in population size ovcr thc study
period had all incrcascd. Thc mcan r valuc lor all survcy scctions was 0.053 l-<br />
0.015, indicating a Dean annual rate of incrcase ot 5.48a per ycar ovcr thc<br />
period of study. The rale of increase in the haryesled scclions (0.051 ! 0.012;<br />
5.2Ea pe( yeat) was slightly lcss than the mean rate in the three nonharvestcd<br />
sections (0.070 i 0.086; 7.3qo per yca(), although lhcy werc highly<br />
variablc.<br />
Tablc 13. Exponcntial ratcs of increasc (r) [or C. porosus in rivcr syslcms<br />
surveyed by spotlight. In lhe 4 inslances where no crocodiles wcre<br />
spottcd in a particular crcck, in any onc ycar, I sighting has bccn<br />
addcd so that a log (ln) vaiuc could bc computed. + indicatcs a<br />
significant regrcssion relationship; 'H' indicates areas lrom which<br />
eggs are harvesred each year. "Last NH-D" = lhe non-hatchling<br />
densily rccorded during lhc last survcy.<br />
Survey Arca N Ycars Last<br />
NH,D<br />
P<br />
Adelaidc - downslrcam<br />
Adelaide - upslrcam<br />
Adclaidc - sidccrceks<br />
Blyth - mainstream<br />
Blyth - sidecrecks<br />
Cadcll - mainslroam<br />
Finniss - Bullcoin<br />
Finniss - Palj Patj<br />
Liverpool - Gudjcrama Ck<br />
Liverpool - mainstrcam<br />
Liverpool - Atlas Ck<br />
Livcrpool - Maragulidban Ck<br />
Livcrpool - Morngarrie Ck<br />
Liverpool - MunSardobolo Ck<br />
Livcrpool - Tom's Ck<br />
Reynolds - McEddy's<br />
Rcynolds - Noaklies<br />
Rcynolds - Wclltrce<br />
Tomkinson - mainstrcam<br />
Daly - mainstrcam<br />
Reynolds - Dccp Hole<br />
Rcynolds - Horscshoc<br />
Harveslcd<br />
Non-harvcslcd<br />
Total<br />
8<br />
11<br />
t'7<br />
15<br />
't7<br />
8<br />
8<br />
14<br />
t5<br />
l3<br />
l5<br />
l5<br />
15<br />
t0<br />
8<br />
8<br />
l)<br />
9<br />
8<br />
19<br />
3<br />
22<br />
r9'/7 -9r 4.36<br />
1977-91 6.34<br />
19'7'7 -91 1.57<br />
t9'15-91 6.17<br />
1975-91 0.69<br />
r975-9r 4.46<br />
1984,91 20.00<br />
0.03?<br />
0.068<br />
0.034<br />
0.029<br />
-0.034<br />
0.003<br />
0.092<br />
0.01*ll<br />
246<br />
I<br />
E'<br />
9.<br />
>'6<br />
o.<br />
I<br />
a<br />
a 10 12 14<br />
Years Since Protection<br />
Figurc 5. The rclalionship betwcsn lhe mean dcnsily of non-hatchling C_<br />
polasrr (helicoptcr count/count equivalents) and ycars since<br />
protection (1971). Valucs for ycars 4-17 (1975-1988) are correcrcd<br />
spotlight counts. Thc last 4 values arc mean helicopter counts.<br />
Over the last four years, thc hclicopter counts have demonstralcd mean<br />
values and Ievels of varialion consisfcnl with those prcdicted {rom spollight<br />
counts, This tcnds to support our contention that tho correclions used ro<br />
derive hclicopter count equivalents from spotlight counls wcre realistic. It<br />
also supports the hyporhcsis thal a largc proportion oI the variation rn<br />
numbcrs of C. porosus sccn in tidal rivers from year to ycar reflccts variation<br />
in thc extent of the populalion found in such rivcrs; rcal riscs and falls in thc<br />
lotal population arc much nlore sub(lc.<br />
Thc rcgression line relating helicoprcr count densiry (HD) to ycars sincc<br />
prolcction (Y)(Fig.5) dcscribes the mgan increase in thc dcnsitv of animals<br />
sighted with time sincc proteclion:<br />
HD=0.12 +00286Yr0.003 (R2=0.86;<br />
P=0.0001)<br />
When used to calculate r, thc helicopler counts give an cstimate of 0.063 :l<br />
0.007 (R2= 0.84; P = 0.0001), indicaring a mean rare o{ incrcasc of 6.5% pcr ycar<br />
ovcr the period 19'15 to 1992. This cstimatc is consistent wilh thc mean valuc<br />
derived from spotlight counts within 8 rivers (0.053 :L 0.015; 5.4o/o per ycar\<br />
discussed above. The two methods are rhus giving comparablc rcsults for C.<br />
polosi./s, whereas thcy are widely divcrgent with C. johnstoni (see abovc).<br />
The size distribulion of C. parosus sighlcd in the helicoprcr survcys (Tablc<br />
14) has shown no significanr changc over rhc four years rhat thc mcrhod has<br />
bccn used,
Table 14. Size dislribution of C.<br />
Nunrbcrs ;n bmckcls Zdrorrs sighted in bclicoptcr survcys.<br />
arc pcrccnragcs.<br />
Ycar Total Small Medium Large Extra-large<br />
1989<br />
1990<br />
1991<br />
1992<br />
461<br />
454<br />
407<br />
53s<br />
41<br />
( 8.9)<br />
48<br />
(10.6)<br />
38<br />
(e.3)<br />
49<br />
(9.2)<br />
ll5<br />
(24.9\<br />
116<br />
r22<br />
(3 0.0<br />
)<br />
196<br />
( 3 6.6)<br />
224<br />
(48.6)<br />
236<br />
(5 2.0)<br />
184<br />
227<br />
(42.4)<br />
81<br />
(r'7<br />
.6)<br />
54<br />
(11.9)<br />
63<br />
( 1s.5<br />
)<br />
(l1.8)<br />
241<br />
In 1984, the lotal wild C. Pororrs populalion (hatchlings and nonhatchlings)<br />
was estimalcd to be at lcast 40,000 individuals (Webb ?t al. 1984).<br />
As mean density derivcd from thc rcgrcssion line on Fig.5 has increascd from<br />
0.50 km-l to 0.?2 km-l betwcen 1984 and 1992 (a 447o increasc), thc lotal<br />
population in 1992 is now estimatcd to bc at lcast 57,600 C. porosus.<br />
MONITORING . CROCODILE FARMS<br />
Thcre are currently six crocodile Iarms in thc No hem Terrilory. Total<br />
captivc stocks havc bcen incrcasing sleadily (Tablc 15)' as has the<br />
producrion of C. potosus through caplive brceding (Table 16). Culling for<br />
skins and mcat was initiatcd in 198?, and sincc that time lhere has bccn a<br />
stcady incrcasc in produclion (Tablc 17).<br />
Table 15. Increascs in lhe caplive population of crocodilcs hcld on Norlhem<br />
Territory crocodile farms- Stocks are at 31 Decembcr cach year. as<br />
rcported in the monthly stock retums. Culling and exPon of skins<br />
slarted in 1987.<br />
Year Numbcr of<br />
Farms<br />
198 7<br />
1988<br />
t989<br />
1990<br />
1991<br />
4<br />
4<br />
4<br />
6<br />
C. porosus C. johnstoni Tolil<br />
5711<br />
't172<br />
9183<br />
12,986<br />
14,40',7<br />
10,543<br />
12,267<br />
r 5,601<br />
15,450<br />
1'7 ,83'.7<br />
16,254<br />
19,439<br />
24,7',7 4<br />
28,436
248<br />
Table 16. Numbers of hatchlings produccd through<br />
Northern Territory crocodilc farms. * this<br />
ncsting season,<br />
Ycar No. of<br />
Farms<br />
19 83<br />
1984<br />
1985<br />
1986<br />
1987<br />
r988<br />
19 89<br />
1990<br />
l99l<br />
1992<br />
3<br />
3<br />
3<br />
3<br />
3<br />
3<br />
3<br />
4<br />
6<br />
C. porosus C jnhnstoni Tolal<br />
99<br />
362<br />
6'7 5<br />
614<br />
444<br />
922<br />
I t2o<br />
t5'7 6<br />
2436<br />
26<br />
105<br />
95<br />
t67<br />
116<br />
90<br />
164<br />
91<br />
captivc brecding on<br />
asscssment<br />
donc bcfoac<br />
125<br />
467<br />
55li<br />
842<br />
730<br />
534<br />
l0u6<br />
12t 1<br />
1634<br />
2436<br />
Tablc 17. Numbers of skins produccd in thc Northcrn Terrilory sincc 19g7.<br />
1987<br />
1988<br />
198 9<br />
1990<br />
1991<br />
No. of<br />
Firms<br />
4<br />
4<br />
4<br />
6<br />
C. porosus L. lohnsront t ntal<br />
251<br />
962<br />
1402<br />
1954<br />
2381<br />
1020<br />
923<br />
t3'13<br />
908<br />
574<br />
1982<br />
2325<br />
3327<br />
3289<br />
Given thai mortalifics on farms arc usually highesr during the firsa ycar<br />
of life, thc moniforing program is bascd largciy on inu"rrto.i-"* of l-vcar_<br />
olds. There is significant varialjon between farms, and wiLhin thc one farm<br />
from ycar to year, in bolh growlh and morlalily ralcs. Mean mortalirics aDd<br />
srzes al one year ol agc, arc summarised on Tablcs 18 and 19 respectivcly.<br />
Table 18. Mean perccnlage mo alily bctwecn hatching and onc ycar of<br />
on Nonhcm Territory crocodile farms. N = number of firms. *<br />
two farms had C. johnstoni, but invcntories at one wcre at l8<br />
monlhs (data not inc lud e(<br />
Ye ar C. porosus<br />
Mcan<br />
i SE Min. Max.<br />
1986<br />
r987<br />
198 8<br />
r 989<br />
1990<br />
1991<br />
62.5 a I {J.0<br />
24.6 t 6.5<br />
29.9 t 2.5<br />
31.2 r 3.9<br />
26.3 r 10.1<br />
36.3 t 11.-l<br />
28.1 89.0<br />
18.0 31.1<br />
25.7 34.3<br />
24.6 38.1<br />
10.9 45.3<br />
7.2 63.9<br />
age<br />
C. johnstoni<br />
N Mean ! SE Min. Max. N<br />
3<br />
2<br />
3<br />
3<br />
3<br />
4<br />
1'7 .0 ! - 17.0 17.0<br />
15.2 i 10.6 4.5 25.8<br />
9.8 L 5.2 4.6 15.0<br />
16.4!<br />
13.4!<br />
6.1 4.5<br />
- 13.4<br />
24.5<br />
13.4<br />
I<br />
2<br />
2<br />
3<br />
l*
Table 19. McaD roral longlh of one-yclr,old crocodilcs on Norrhcrn Territory<br />
crocodilc 1arms, for ycars in which thcrc are comparablc data. N =<br />
nunbcr of farms. * = lwo farms had C. johnstoni, bur inventorics ar<br />
onc wcre at 18 months (data not includcd).<br />
Ycar C. porosus<br />
Mcan i SE Min. Max. N<br />
198'7<br />
1988<br />
r989<br />
1990<br />
199 |<br />
696.4 !<br />
689.7 t<br />
675.8 r<br />
687.5 r<br />
3.3<br />
3.2<br />
2.'7<br />
313<br />
340<br />
307<br />
304<br />
1075 3<br />
1262 3<br />
1279 3<br />
13'14 4<br />
RESEARCII<br />
l. Homing<br />
C. johnstoni<br />
Mean i SE Min. Max. N<br />
t)n I +<br />
569.2 t<br />
561.'7 !<br />
573.1 !<br />
541.1 i<br />
- 408 811<br />
t.2 407 791<br />
t.2 347 820<br />
1.1 354 1198<br />
1.9 359 635<br />
Thc rcsul!s of rclocating problcm C. porosus ,m Covc, on tbc norlh-cast<br />
corncr of the Nortbcrn Tcrritory (Fig. 1), wcrc rcccntly analyscd by Walsh<br />
and Whilchead (1992). Govc is a largc area of Aboriginal Land, whcrc<br />
crocodilcs arc of totcmic significance to the local pcople. Thcy objccted to<br />
crocodiles bcing killcd and/or g;vcn to thc crocodilc fanrs. Accord;ngly, of<br />
52 problcn crocodifcs caught bctwccn 1986 and 1991, 48 (92o/a\ wctc rclocdLcd<br />
in the wild bclween 1? and 282 km away lrom their capturc sitc. A<br />
significant proportion (487o) were recaughr at lhe samc caplurc locirtions al<br />
Ieast once. The probabilily of rccapturc could not bc a(ribuled stalistically to<br />
sizc, scx, season, distance or dircction of rclcaso.<br />
2. Recovery Trends in tlre Blyth-Ccdell River System<br />
The survcy program in rhc Blyrh-Cadell River systcm, started by Harry<br />
Messcl (Messcl ct al. l98l), has bcen conlinucd by the Conscrvation<br />
Commission. An analysis of 17 years dat^ (19'74-1990\ has now becn<br />
undertaken (Wcbb and Manolis 1992), and thc rcsults arc summarised rcrc.<br />
spotlight coonts wcrc converted to estimatcs of total population size, ano<br />
thcn sizc classes of juvcniles werc converted !o age classcs as dcscribcd<br />
prcviously (Wcbb et aI. 1984),<br />
Thc total population was rclalivcly slable betwccn 3 and 14 ycars aftcr<br />
protection (Fi8. 6), but thcn increascd significantly. This incrcase was<br />
comprised maiDly of increased numbcrs of hatchlings (Fig. 7), but it was no1<br />
rcflected in thc 1-ycar,olds, rhe following ycar (Fi8.8). The numbcr of lycar-olds<br />
in thc populalion has steadily declined since protection (mcan =<br />
to3.2 ! 7.6).<br />
249<br />
I<br />
2<br />
2<br />
3<br />
l*
250<br />
E]<br />
N<br />
z<br />
z-<br />
I<br />
F.l<br />
J<br />
F<br />
,t<br />
F<br />
F<br />
900<br />
800<br />
700<br />
600<br />
500<br />
400<br />
a<br />
300<br />
2 6 8 10<br />
a<br />
12 t4 t6 18 20<br />
YEARS SINCE PROTECTION<br />
Figure 6. Estimaled total populalion of C. poros s in the Blyth-Cadell River<br />
system between 1974 and 1990.<br />
500<br />
450<br />
400<br />
350<br />
300<br />
250<br />
200<br />
150<br />
100<br />
50 2<br />
Figure 7. Estimated tolal<br />
6 8 l0 t2 14 16 18 20<br />
\TARS SINCE PROTECTION<br />
popufation of hatchlings between 1974 and 1990.<br />
a
tt<br />
F]<br />
F<br />
F<br />
160<br />
140<br />
120<br />
100<br />
80<br />
60<br />
40 2 6 8 l0 t2 t4 16<br />
YEARS SINCE PROTECTION<br />
18 20<br />
Figure 8. Estimated total population of 1-year-olds between 1974 and 1990.<br />
In contrast, the numbers of 2-year-olds (Fig. 9) declined precipirously<br />
throughout the posFprotection period, and the impact of that decline was<br />
clearly carried on to the 3-year-olds (Fig. 10).<br />
../)<br />
,..1<br />
c.l<br />
!<br />
140<br />
120<br />
100<br />
80<br />
60<br />
40<br />
20<br />
a<br />
a<br />
a<br />
a<br />
a'<br />
a<br />
a a<br />
a<br />
to<br />
a<br />
a<br />
a a<br />
a<br />
a<br />
a a a<br />
a<br />
0 2 6 8 l0 12 t4 16 I<br />
YEARS SINCE PROTECTION<br />
Figure 9. Estimalcd toral populalion of 2-year-olds bclwcen 1974 and 1990.<br />
a<br />
a<br />
a<br />
a<br />
ao<br />
20<br />
251,
252<br />
v)<br />
t-.1<br />
'J<br />
F<br />
F<br />
90<br />
80<br />
70<br />
60<br />
50<br />
40<br />
30<br />
20<br />
a<br />
!.'<br />
aa<br />
10<br />
2 6 8 l0 12 t4 16<br />
\€ARS SINCE PROTECNON<br />
a<br />
a<br />
a<br />
a<br />
O<br />
18 20<br />
Figurc 10. Estimarcd<br />
rclal population 3-ycar,olds betwecn 1974 and 1990.<br />
Numbcrs of 4,yeaFolds (pig. tl) increased slightty in the jmmediarc posr_<br />
protection period, buI dcclined aftcr abouL l0 ycais. Similarly, 5_ycar-otds<br />
(Fig. 12), showed a sharp incrcasc during rhe first I0 ycrrs. aftcr which<br />
numbers stabilised.<br />
,-.1<br />
J<br />
F<br />
F<br />
50<br />
4l<br />
40<br />
35<br />
30<br />
25<br />
20<br />
l5<br />
a<br />
a<br />
l0 z 6 8 10 12 t4 16<br />
YEARS SINCE PROTECTION<br />
Figure 11. Estimated<br />
total populalion 4-ycar,olds bctwccn 1974 and 199U.<br />
a<br />
20
Numbers of oldcr, larScr animals in thc population (6.3+ ycarsiFig.<br />
l3)<br />
incrcased slowly during thc first l0 ycars, thcn sharply lo aboul 15 ycars,<br />
when thcy appeared 1o slabilisc.<br />
J<br />
gt<br />
J<br />
F<br />
F<br />
35<br />
30<br />
25<br />
20<br />
l5<br />
l0<br />
5<br />
4 6 8 l0 t2 t4 16<br />
YEARS S]NCE PROTECNON<br />
zo<br />
Figure 12. Estimated total population 5-year-olds between 1974<br />
and 1990.<br />
J<br />
.t<br />
J<br />
3<br />
250<br />
225<br />
200<br />
t'7 5<br />
150<br />
I 25<br />
100<br />
75<br />
50<br />
i.'<br />
a<br />
25<br />
2 6 8 10 12 14 16 18<br />
YEARS SINCE PROTECTION<br />
Figure J3. Estimated roralpopulalion 6+ year-dds betwecn 1974 and 1990.<br />
a<br />
a<br />
a<br />
a<br />
a<br />
a<br />
z0<br />
253
_Generally,<br />
ir appears that as the number of older, larger crocodiles (6+<br />
year-olds) increased, numbers of 2-year-olds, 3-year-olds and cventually 4_<br />
year-oldt and 5-year-olds were affecled. Further insighrs can be sained<br />
from "retenrion rates" - the ratio of the number of a given year ciass sighted<br />
in a river in any one year, versus the number of the -next yiar class sightcd<br />
the next year (Table 20).<br />
Table 20. Retcntion rates of C. porosus year classes in consecutive years.<br />
Values greater than 1.0 reflect a net gain, which can bc ;ttributed<br />
to many causes including survey biases. p = probabili!v associated<br />
with a regression line relating relcnrion rate io years'since<br />
protection: "Trend" indicates whether the ratio increascd (+) or<br />
clecreased (-).<br />
Ycars 0.3 - 1.3 1.3-2.3 2.3-3.3 3.3-4.3<br />
197 4-7 5<br />
1915-7 6<br />
1976-'17<br />
1977 -78<br />
r97 8-79<br />
1979- 80<br />
1980- 8 r<br />
l9 81 -82<br />
1982-83<br />
1983-84<br />
19 84-85<br />
19 85- 86<br />
198 6- 87<br />
r987-88<br />
1988-89<br />
19 89-90<br />
P<br />
Trend<br />
Mean<br />
|.17<br />
1.13<br />
0.80<br />
0.59<br />
0.56<br />
0.71<br />
0.68<br />
0.59<br />
0.7 6<br />
0.84<br />
0.90<br />
0.94<br />
0.36<br />
1.51<br />
0.3 6<br />
0. l4<br />
0.23<br />
0.7 5<br />
0.61<br />
0.47<br />
l.l8<br />
0.95<br />
0.93<br />
0.50<br />
0.53<br />
0.50<br />
0.95<br />
0.27<br />
0.15<br />
0.5 8<br />
0.62<br />
0.34<br />
0.25<br />
0.09<br />
0.01<br />
0.56<br />
0.61<br />
0.66<br />
1.04<br />
0.7 4<br />
r.o2<br />
0.69<br />
o.79<br />
0.87<br />
0.9 8<br />
0.59<br />
0.68<br />
t.72<br />
1.06<br />
0.84<br />
0.45<br />
0.82<br />
0.63<br />
0-85<br />
0.51<br />
0.26<br />
0.65<br />
0.50<br />
0.64<br />
0.46<br />
0.52<br />
0.77<br />
0.66<br />
0.59<br />
0.64<br />
|.24<br />
0.79<br />
0.7 4<br />
0.3 8<br />
1.13<br />
0.03<br />
0.65<br />
Hatchlings and l-year-olds do not disperse greally from their nest sitos<br />
(Webb and Melsel l9?8) and the RR0-t should be a ieasonable index of<br />
hatchling mofialily Iactually mortalily belween 0.3 and 1_3 years of ags<br />
(mean = 0.75), becausc surveys are conducred mid-year, abour 0.3 vcars aftcr<br />
peak hatching). Thc RRo.l declined as a function of thc number oi<br />
hatchlings in the river (Fig. 14; R2= 0.68 p = 0.0001). This rclalionshiD was<br />
not improved by enlering, in various ways, rhe numbcrs of older or largcr<br />
crocodiles inlo the analysis. The rcsult suggests that harchling survival may<br />
be density-dependcnt, and thar largcr crocodiles are lgl the main Dredator<br />
involved. Howevcr, it docs not constirure proof ot dcnsity-depcndenc;, as<br />
lhere is a negativc covariance involved with counts of succe:sive year<br />
classcs, A tendency lo ovcr. or undcrestimatc hatchl;ngs in any onc year, is<br />
nol necessadly followcd by thc same bias wilh l-yoar:olds rtre ncxr year.<br />
Thc RR1-2 dcclined as a function of thc number of older 0areer)<br />
crocodrles jn thc poput ion, and this rclarionship rc:rihed ma,
significance with the number of 6+ ycar-olds (N6+)(R'?= 0.34; P = 0.018); i.e.,<br />
not just non-hatchlings. However, as with the RR0-1, it also declined as a<br />
function ol the numbers of l-year-olds (Nl: R2= 0.33; P = 0.019). which could<br />
reflect negative covadance. Multiple regression analysis, with both<br />
variables, accounted Ior 76Vo of the variation in RRI-2 (RRl-2= 1.57 -<br />
0.0028N6+ - 0.0066Nr; R2 = 0.76; P = 0.0004). when corected for mean<br />
variation aitributable to Nl, the general trend in the relationship between<br />
RRr-2 and N6+ is shown on Figure l5 (RRt-2 = 0,876 - 0.00275N6+; R2 = 0.63; P<br />
= 0.0003). It suggests that the incrcasing losses of l-year-olds may be due to<br />
predation, specifically by the larger crocodiles.<br />
The RR2-3 declined as a function of lhe lotal population of non-hatchlings<br />
(Nt-0i total population minus hatchlings)(Fig. l6) and the relationship was<br />
best modelled by a polynomial regression (RR2-3 = 5.875 - 0.0242N1-6 +<br />
0.0000282Nr-02; R2 = 0.6?; P = 0.0007). The RR3-4 declined as a funclion of the<br />
numbcr of 3-year-olds (R, = 0.49; P = 0.0007; Fig. 17) and the RR4-5 as a<br />
function of the number of 4-ycar-olds, again being better modelled by a<br />
polynomial regression (RR4,5 = 3.2675 - 0.123Na +0.0014Na2: R2= 0.?5: P =<br />
0.0001; Fig. 18): in both cases negative covariance could be involved.<br />
1.6<br />
t.4<br />
> .8<br />
&.o<br />
.2<br />
a<br />
a<br />
a<br />
a a<br />
a<br />
0 5 0 r00 r50 200 250 300 350 400 450 500<br />
TOTAL HATCHLINGS<br />
Figure 14. Retcntion rate (hatchlings to l-year-olds) as a function of the<br />
numberc of halchlinss in the river.<br />
a<br />
255
256<br />
F<br />
a<br />
p<br />
l.l<br />
I<br />
.9<br />
.8<br />
.'7<br />
.6<br />
.5<br />
,4<br />
.3<br />
.2<br />
aa<br />
.1<br />
2 50 7 5 l 00 r25 | 50 1'1 5 200 225 250<br />
TOTAL 6+ YEAR-OLDS<br />
Figurc 15.Rclention rafc (1, to 2-ycar-olds) as a function of 6+ ycar_olds in<br />
thc rivor. Values have been standardiscd significanl variation<br />
attributablc to (hc nun)ber of l-year{lds lsce tcxq.<br />
ca<br />
c.l<br />
1.8<br />
1.6<br />
1.4<br />
1.2<br />
I<br />
.8<br />
.6<br />
a<br />
a<br />
a<br />
a<br />
a<br />
a<br />
a<br />
a<br />
25027 5 300 325 350 37 5 400 425 450 47 5 500<br />
TOTAL NON-HATCHLINGS<br />
Figure 16. Retcntion rate (2- to 3-year-olds) as a lunction of the nunlbcrs of<br />
2-ycar-olds in thc rivc r.<br />
a<br />
a<br />
a<br />
a<br />
a
A1<br />
).n<br />
1.4<br />
t.2<br />
Figure 17. Retention ra!e<br />
3-year-olds in<br />
A<br />
.2 I 20 30 40 50 60 70<br />
TOTAL 3-YEAR-OLDS<br />
z.?<br />
2<br />
1.8<br />
1.6<br />
1.4<br />
1.2<br />
I<br />
.8<br />
.6<br />
.4<br />
a<br />
a<br />
a a<br />
a a a<br />
a<br />
80 90<br />
(3- 1o 4-year-olds) as a function of the numbcrs<br />
lhe dvcr.<br />
.2 I 20 25 30 35 40<br />
TOTAL 4-YEAR-OLDS<br />
45 50<br />
Figure 18. Rctcntion rale (4- to 5-year-olds)<br />
as a lunction oI the numbcrs of<br />
4-year-olds in the river.<br />
Taken<br />
_ _<br />
togclher, thc rcsults soggcst, but do not provide uncquivoca.<br />
cvidence of, a density-dcpcndent clemcnt in thc probability of particular<br />
juvcnile ycar classcs being rcrained in the rivcr. .ihe largeit croiodilcs (6+<br />
a<br />
a<br />
a<br />
a<br />
of<br />
2s7
258<br />
year-olds) do not appear to be a major predator on hatchlings, but are<br />
probably the major predator on l-year-olds. In - contrast, 2-year-olds are<br />
sensitive to the total numbers of non-hatchlings - as against the largest<br />
animals (6+ year-olds) - in the river: perhaps reflecting a spacing need as<br />
proposed by Messel and Vorlicek (1986, 198?) and Messel et rl. (1986). Il so,<br />
emigration would be a likely cause. With 3-year-olds and 4-year-olds,<br />
dcnsity'dependent relationships may exist, but movement rather than<br />
predation is the likely cause of losses.<br />
3. Life History Strategies ol C. johnstoni<br />
Harvey Cooper-Preston's PhD thesis (University of New England) is<br />
undergoing linal revision. She has compared life history lrails and various<br />
aspects of the population dynamics of three distinct populations of C.<br />
johnstoni. The results indicale that life history traits and thus population<br />
dynamics within a species such as C. johnstoni can be highly variable<br />
between arcas.<br />
4. Sex Delermination<br />
The relationship between incubation lemperalurc and sex in embryonic C.<br />
johnstoni is differcnt from that in most crocodilians: no constant incubadon<br />
temperature produces 1007o males (Webb et aI. 198'l), even though 1007,<br />
males are produced in some wild nests (Smith f98?). An obvious hypothcsis<br />
which could explain this result, is that the mechanism of temperaturedependent<br />
sex determination is sensitive 1o daily fluctuations in temperature<br />
as well as to the mean temperature. This possiblity was tested in 1989, using<br />
temperatur€s in th€ range (32"C) that produce lhe highest proportions of<br />
males. No significanr variation in offspring sex ratio was detected between<br />
mildly fluctuating (31-33"C; 0.4f propo(ion of males) and constanr (32oC;<br />
0.39) temperature, and the sex ratios (0.41 and 0.39) were well short of 1007,<br />
males (Webb et al. l990a\.<br />
Clearly, wider fluctuations in temporature may bc nceded to ex€rt an<br />
influence (Georges 1989). However, we decided to pursue a diflerent<br />
approach. Another feature of C. johttstoni incubation in the ficld (which can<br />
produce 100% males), which is not duplicated with constant tempe(aturc, rs<br />
increasing rnean n€st temperatures throughout the incubation period (Webb<br />
et ol. 1983i Snith 1987).<br />
In 1990, this influence was simulated by increasing incubalion<br />
temperatures in 1oC incremcnls throughout ihe incubalion poriod (Table 21).<br />
Depending on the desired star! and finish tempemtures, and thc tcmperature<br />
range, the increments were evenly spaced with development at 30oC. They<br />
were then scaled to other temperatures using temperature dependent<br />
development rate coefficients (Webb et 4l- 1987). For example, 30-35oC and 28-<br />
33'C both involved 5 increments. The first one occurred a! 16 days for the<br />
30.C eggs ^nd. at 22 days for the 28oC eggs (i.e. ir was prolonged so rhat the<br />
increment occurred at the same embryological stage of development). The<br />
second increment was calculaled on the basis of develoDment rate at 3loc and<br />
29oC respeclively, and so on. The eggs uscd for rhis exptriment were 4.7 ! 0.3<br />
days old (N = 314; range 0'19.7 d), when introduced inlo rhe incubators, and<br />
developmenl in rhe field was taken into account when timing the<br />
inctements.
Table 21. Results of incubating C. johnstoni egls<br />
in loc increments throughout incubation<br />
expressed as the proportion of males. N<br />
Treatment<br />
ec)<br />
28-3 |<br />
28-32<br />
29-32<br />
29,33<br />
29 -34<br />
30-33<br />
30-34<br />
30-3 5<br />
3r-34<br />
Sex Ralio<br />
(N)<br />
0.03 (34)<br />
0.00(2s)<br />
0.00 (2'7)<br />
0.04 (2't)<br />
0.14(36)<br />
0.53(19)<br />
0.72 (47)<br />
o.72 (18)<br />
0.80 (20)<br />
0.56 (36)<br />
0.36 (25)<br />
at temperatures increased<br />
(1990). Sex ratio is<br />
= number of hatchlings.<br />
Dead during<br />
Incubation (7o)<br />
29.5<br />
t'|.9<br />
40.3<br />
20.8<br />
8.3<br />
9.3<br />
20.3<br />
39.1<br />
_<br />
Some escalating lemperalures clearly gave a much higher proponion of<br />
malgs (
260<br />
Table 22. Rcsults of incubaling C. johnstoni eggs in 1991. Scx ratio is<br />
expressed as the proporrion of males. 'Esc. 30-35'= tempcfaturcs<br />
increasgd gradually throughout incubation from 30oC to 35oC:<br />
'Switch 31-32'= eggs began incubation at 3loc and afler 22 days<br />
were switched to 32oC (see Webb e/ dl. 1987). N = number of<br />
hatchlings.<br />
Treatment<br />
(oc)<br />
Sex Ratio<br />
(N)<br />
Ago at Collection: 0-5 days<br />
Constant 32<br />
Switch 3l-32<br />
Esc.30-35<br />
Age at Collection: 0-10 days<br />
Constant 32<br />
Switch 3l-32<br />
Esc.30-35<br />
0.2'7 (tt)<br />
0.78 ( 9)<br />
1.00 ( 9)<br />
0.30 (20)<br />
0.61 (28)<br />
0.88 (17)<br />
Dead during<br />
Incubation (%)<br />
5 6.0<br />
56.'7<br />
52.8<br />
52.0<br />
44.8<br />
56.7<br />
5. Scrling of An:rerobic Muscle Work in C. porosus<br />
John Baldwin (Monash University) and Bill Runciman (Royal Adclaide<br />
Hospiral) joined Rogcr Seymour (Univcrsity ol Adclaidc) in anolher round of<br />
experiments on thc physiological cffccts of capture on C. 2orosas. As bclorc<br />
(Bennett et dl. 1985; Scymour et al. 7985, 1987), blood samplcs (and this timc<br />
muscle samples) were laken from crocodiles !hat had strugglcd to exhauslron<br />
during capture.<br />
LarSe crocodiles struggled for longer periods bcforc bcinS fatigucd and<br />
produced more lactic acid lhan smaller animals. Howevcr, smallcr aninals<br />
produced lactic acid faster. bul for a shorter period. Thc ratc of lactate<br />
production correlates with the higher aclivitics of ratc limiting glycolytic<br />
cnzymcs in thc muscles. Small crocodilcs becomcd exhaustcd when all thcir<br />
musclc glycogen is used up, whilo Iarge animals rctain around 257o of their<br />
inilial muscle glycogen slorcs following exercise. Although thc results are<br />
still bging analysed, the results may provide new insights into why large<br />
crocodiles sometimes die during capture. Smallcr crocodiles, with higher<br />
mass spccific aerobic metabolism, nray b€ able 10 rccovcr acrobically using<br />
lipid fucls. Largcr onos, with lower mass spccific acrobic mctabolism, miry<br />
require a glycogcn buflcr to allow some anaerobic melabolism during thc<br />
initial recovcry phase. If all the musclc glycogen was used up (during<br />
extrcmo struggling of largc crocodiles), thcy may noi be ablc to fucl this<br />
initial recovery phase.<br />
It was suggestcd previously (Scymour et aL. 198'7) that artificial<br />
respiration could bc an effcctive method for enhxncing thc rccovery of<br />
large crocodiles with mctabolic acidosis. This was testcd via an cndotrachcal<br />
tube using both an oxygen jet and I slandard human resuscitalion apparatus<br />
consisting of a large rubbcr bulb pump and a one,way valve. Both<br />
tcchniques provcd elfectivc. Blood samples indicated an immediate incrcasc<br />
in blood pH, due lo thc blowing off of CO2, and a drop in btood lacrare levcts ar
about twice the rate oI unvcntilated animals.<br />
Animals wcre immobilised wirh gallamine rriethiodidc (,,Flaxcdil"), bur a<br />
short'term musclc rclaxant, Atricurium, was tested. lntramuscular injcctions<br />
resulted in paralysis for l5 minutes !o scveral hours, wirh spontaneous<br />
recovery without an antidote. Atricurium is used as a reDlaccment for<br />
Flaxedil in hospirals and is pracrical for use wirh crocodiiians, allhoush ir is<br />
expcnsive and rcquircs refrigcrar ion.<br />
6. E{rly Embryonic Stages of C. johnstoni<br />
The ea y devclopment of crocodilian embryos occurs while the eggs arc<br />
in the oviducls, and they have rarcly been retricved and studied. Ruth<br />
Bellairs (University ol London) has starled a research projcct on this pcriod<br />
of development, with parlicular referencc to the devclopment oI thc<br />
primitive slreak.<br />
Soft-shelled oviducal eggs were rcmovcd from gravid lemale C. johnstoni.<br />
Thc eggs were maintained in an incubalor and cxamined in a scies as<br />
developmcnt procceded. Two females were sacrificed for the eggs, after<br />
attempls to induce oviposilion wirh oxyrocin (Carmel l99l) failcd. Alrhough<br />
some eggs were laid with the oxytocin trealment, we could not gct thc<br />
completc clutch to be voidcd. Cloarly, we wcrc trying to induce laying somc<br />
2-3 weeks bcforc nalural oviposition, and thus thc uterine sections of the<br />
oviduct may not havc been particularly rcccptivc. We were also<br />
administering the oxytocin in single intramuscular injcclions which may<br />
not have bccn idcal. Oxytocin may wcll {unction eflicienlly at or ncar thc<br />
time of natural oviDosition.<br />
7. Captive Husbandry of C. porosus<br />
Gregor Riese [Crocodilc Farms (N.T.) Pty. Limited] is invcstigating various<br />
aspocts of thc captivc husbandry of hatchling C. poroJts. Trials in l99l<br />
(Riese l99l) found large clulch spccific varialion, and a signilicant<br />
relationship betwoen growrh rare (g d_1) and initial s;ze (snout-vcnt<br />
length). The filming of halchlings revealcd Ircquenr aggrcssive<br />
interactions: aggression and dominance behaviour appear to influencc<br />
grcwth rates cvcn in thc immediatc posFhatching period.<br />
Trials in 1992 confirmed that dcnsity effccts are of primary influencc ln<br />
the first 6 weeks of growth, allhough they can be mcdiated !o somo exlenr by<br />
pen design- Light conditions (low,wattage fluorcsconl globes: l2 h on, 12 h<br />
off) gave supcrior growth to dark conditions. Hatchling bchaviour is<br />
considered 10 be the key proximate variable affecting halchling growth.<br />
8. Densily versus Spac€ \yith I{atchling C. porosus.<br />
The success with which C. porosut can bc farmcd is partly dcpendent on<br />
tho timc takcn for ncw halchlinSs !o sct|le and begin fccdinS. previous<br />
oxperimcnts havc examincd thc cffccls of a ranqc oI diffcrent variabtcs<br />
within thc lirst month, particularly lood (wcl)b ei at. 1990a). In t99t, etlccrs<br />
of density and maximum space were examincd. The differcnce belwccn<br />
density and maximum spacc is bcst oxplaincd by example. If two adjaccnt,<br />
identical pens had !he samc numbers of animals (samc dcnsity), and thc<br />
partition separating rhcm was lified, thc dcnsity would be lhe samc, but<br />
26'l
2A<br />
maximum space would double.<br />
The experiments were conducted in large fibreglass tanks subdivided wift<br />
partitions ilrto 4 pens of 1.7 m2, etith 44% l^nd ^nd 54% warer (maximum<br />
depth l0 cm) maintained ar 32oC. For all treatments the dier consisred of a<br />
minced mixture of potk (75%) and chicken heads (25Vo\, with dicalcium<br />
phospato and vilamin premix ("Petvite") added at rates of 2Eo and l%<br />
respectively. Hatchlings were placed in tho pens within 2 days of hatching,<br />
and were fed 7 days per week. Food was presented in the evening (1630-l?30<br />
h) and the waste removed the following morning before draining, cleaning<br />
and refilling (0830-1000h). All crocodiles had their head lengrhs (HL) and<br />
total lenghs (TL) measured at introduction and after l month.<br />
Because grcwth irr C. pororus hatchlings is subject to pronounced clutch<br />
effects, three clutches were divided evenly amongst the four density<br />
trcalments. The results, in terms of percentage change in HL and TL, are<br />
summarised in Table 23. As expected, dramatic clutch e{fects occurred, and<br />
they were highly significant (ANOVA qoHL a[td Eo"fL vs CLUTCH; P
The maximum size and the minimum size, for borh %HL and TL, are also<br />
indices of perfonnance. When ranked from 4 (best growtb) to I (worst<br />
growth) (Table 24), some interesting lrends are apparent. Firstly, lho<br />
distribution of total scores is significantly different betwocn minimum and<br />
maximum values (Chi-square = 8.49; DF = 3; P = 0.037). SecoDdly, rhe highesr<br />
densily trealment (l?.6 m_r) gave the poorest perfonnance in terms oi both<br />
maximlm and minimum sizes: this density, evcn within the firsl month, is<br />
probably too high for C. polorlr harchlings. Thirdly, maximum and<br />
miDimum size lendcd to be negatively correlated. At low densities (7.1 m-:<br />
and 10.6 m-2) lhe minimlm sizes wcre larger, whereas the opposite trend<br />
occurred at higher densities.<br />
Table 24. Ranking of the maximum size (4 = highesri I = lowcst) and minimum<br />
growth (4 = highest: I = lowest) of head length (%HL) and total<br />
lengrh (z,TL) for rhe individual clutches used in rhe densiry<br />
cxperimenl. Totals = percenrage of maximum possible scorc (iZ C =<br />
24) for both minimum and maximum values.<br />
"<br />
Density Clulch M7<br />
(m-2) VoHL lo"fL<br />
Mi. Mx. Mi, Mx.<br />
1.1<br />
10.6<br />
l4.l<br />
17.6<br />
263<br />
Clutch Al8 Clutch D24 Totals<br />
%HL %"IL %HL<br />
Mi. Mx. Mi. Mx. Mi. Mx.<br />
%TL<br />
Mi. Mx. Mi. Mx. (N)<br />
83% 587o<br />
83% 63Ea<br />
42% 7 5Eo<br />
42% 54%<br />
The four experiments on maximum space involved animals from various<br />
clutches, divided between two pens (in one tank) of unequal size (1.7 m2and<br />
5.1 m2). Because each of the iour experiments was carried out in differenl<br />
lanks, with slight variation in therII|al characteristics, precise comparisons of<br />
densily between tanks may be compromised.<br />
Mortality was a variable of significance (Table 25), in that pens with large<br />
numbers of harchlings resulted in losses due to piling. Our results suggest no<br />
more lhan 35-40 hatchlings should be kept together in any conventional pen<br />
conducive to piling.<br />
The growth rcsuhs from the maximum space experimenls are in Table 26. In<br />
the first experiment, density was held conslant at 7.7 m-x. The results indicated<br />
that clutch exerted a significant effcct on growth (ANOVA %HL, %TL vs CLUTCH;<br />
P = 0.004, 0.007 respecrively), but there was no effect from the treatmcnl, nor any<br />
interaction between treatment and clutch.<br />
In the second experiment, density was held constant at 10.6 m'2. The only<br />
sigtrificanl eflect on growrh was again clulch (ANOVA %HL, %TL vs CLUTCH;<br />
P = 0.01,0.02 respecrively). In the rhird experimenl, densiry was increased to<br />
14.1 m-2. The only significanr cffecr on growth was clurch, bur only with %TL<br />
(not HL) (ANOVA %TL vs CLUTCH; P = 0.03). I lhd fourth experimenr,<br />
densily was increased to 17.6 m'2. The only silnificant effect o; growth was<br />
34<br />
28
264<br />
clutch (ANOVA o/oHL, qoTL vs CLUTCHi p = 0.0001). Taken rogcthcr, rherc was<br />
no significant effect ol treatment, nor any interaction bctween treatment<br />
and clutch, in any of the expciments. Clutch effects were highly<br />
srgnrtrcant.<br />
Table 25. Percentage mortalitics lor C. porosus hatchlings maintained at<br />
different densitics and amounts of available space for the first<br />
month after hatchins.<br />
Density Space N<br />
(m-2) (rn2)<br />
7.L<br />
10.6<br />
t4.l<br />
7.1<br />
10.6<br />
t4.l<br />
r7.6<br />
t.7<br />
1.'7<br />
l.'l<br />
1.7<br />
J_ I<br />
).1<br />
).1<br />
5.1<br />
t2<br />
18<br />
24<br />
30<br />
54<br />
72<br />
90<br />
Mortality<br />
(c"<br />
)<br />
0.0<br />
0.0<br />
0.0<br />
0.0<br />
0.0<br />
1.9<br />
9.7<br />
Table 26. Percenragc increase in hcad lengrh (E|HL) a\d total lcnglh (Z,TL)<br />
Iot C. porosus hatchlings from diflerent clutches maintiined aa<br />
different densities and amounts o{ maximum space for the ftrst<br />
month after hatchin[.<br />
Clutch N Density Space<br />
(m-,) (m2)<br />
F24<br />
F24<br />
A3<br />
A3<br />
ALL<br />
ALL<br />
D26<br />
D26<br />
L4<br />
L4<br />
All<br />
All<br />
6<br />
1E<br />
6<br />
18<br />
t2<br />
36<br />
4<br />
12<br />
ll<br />
5<br />
7.1<br />
7.1<br />
7.r<br />
7.r<br />
't .1<br />
7.1<br />
10.6<br />
10.6<br />
10.6<br />
10.6<br />
10.6<br />
10.6<br />
1.7<br />
).1<br />
t,7<br />
).1<br />
1.7<br />
)_ I<br />
1.7<br />
5.1<br />
1.7<br />
5.1<br />
1.7<br />
5.1<br />
%HL SE Ran ge %TL SE Rangc<br />
18.6 1.30<br />
r9.'7 r.16<br />
2t.6 1.29<br />
25.t 0.94<br />
14.6-23.0 16.r<br />
I 1.6-30.8 14.6<br />
t9 .2-25 .8 t8 .7<br />
t8.8-32.8 22.0<br />
20.1 0.99 t4.6-25.8 t'7.4<br />
22.4 0.87l1.6-32.8<br />
18.3<br />
16.6 t.04<br />
18.8 | .45<br />
21.6 1.47<br />
21.0 1.02<br />
14.'7-18.5 12.t r.2r<br />
r0.7-26.5 13.3 1.15<br />
t8.7 2.t0 13.7 -23.9 12.6 1.52<br />
22.2 1.50r2.6-30.5<br />
15.5 1.37<br />
1.37 12.I-20.3<br />
r.46 6.6-29.0<br />
t.l9 11.9-21.7<br />
1.22 15.5-34.5<br />
o.95 12.r-21.7<br />
1.r2 6.6-34.5<br />
8.7,14.0<br />
6.t -20.0<br />
16.3-24.9 13.0 r.16 8.9- 15.7<br />
15.5-27.8 12.2 0.7'7 7.6- 18.5<br />
8.1-14.4<br />
8.3-23.1
Tablc 26 continued.<br />
Clutch N<br />
F18 5<br />
F18 15<br />
ALL 18<br />
ALL 53<br />
T2<br />
18<br />
F2r 6<br />
F2r 15<br />
M56<br />
M5 t7<br />
Ft 6<br />
F7 15<br />
ALL 24<br />
ALL 65<br />
MRI 6<br />
MRI I8<br />
R1l 6<br />
Rll r8<br />
D23 9<br />
D23 25<br />
829<br />
B2 26<br />
ALL 30<br />
ALL 87<br />
D cnsi ty<br />
( m-2)<br />
10.6<br />
r 0.6<br />
10.6<br />
10.6<br />
t4.l<br />
t4.r<br />
t4.l<br />
t4.l<br />
t4.l<br />
t4.t<br />
14.1<br />
t4.l<br />
14.1<br />
t4.l<br />
17.6<br />
17.6<br />
r7.6<br />
17.6<br />
r7.6<br />
17.6<br />
17.6<br />
r7.6<br />
17.6<br />
t'7 _6<br />
Space<br />
(m2)<br />
t.'7<br />
J.l<br />
t.'7<br />
5.1<br />
1.7<br />
t.'7<br />
5.1<br />
t.7<br />
). t<br />
t.7<br />
5.1<br />
1.7<br />
5.1<br />
1.7<br />
1.7<br />
5.1<br />
t.'7<br />
).1<br />
r.7<br />
5.1<br />
t.'l<br />
5.1<br />
loHL Range Range<br />
23.2 r.97 20.3-30.8<br />
t1.2<br />
23.3 0.96 r7.9-29.0 15.6<br />
0 14.8-23.0<br />
9.1-20.2<br />
20.3 0.99 13.'t-30.8 13.9 0.79 8.1_23.0<br />
21.4 0.63 10.7-30_5<br />
14.1 0.54 6.1-23.r<br />
18.8 0.97<br />
18.2 0.88<br />
16.5 1.07<br />
18.8 0.94<br />
19.2 1.37<br />
18.6 0.73<br />
16.7 1.53<br />
16.7 1.02<br />
r7.8 0.64<br />
18.1 0.45<br />
14.7-20.8 t4.'l<br />
9.6-23.4 14.1<br />
12.2-20.2 14.0<br />
13.0-27.0 15.1<br />
15.5-24.4 18.1<br />
13.9-24.7 16.3<br />
lr.6-22.5 12.7<br />
9.'t-25.1 12.9<br />
r1.6-24.4 14.9<br />
9.6-2't.0 14.6<br />
t6.2 2.13 9.4-24.3 10.5<br />
17.4 1.10 10.2-26.6 10.6<br />
28.2 2.6r<br />
25.6 1.49<br />
16.6 0.95<br />
19.3 0.94<br />
18.5 1.12<br />
20.5 0.64<br />
19.4 t.l2<br />
20.6 0.58<br />
23 .2-39 .0 25 .2<br />
t3.4,34.6 20.0<br />
10.8-20.1 11.0<br />
10.6-30.4 r 3.8<br />
13 .2-23 .2 12 .0<br />
12.'7 -26.6 14.6<br />
9.4-39.O 14.0<br />
10.2-34.6 14.7<br />
0.95 1r -6- 17.9<br />
0.73 10.2-20.3<br />
r.40 10.2-r9.4<br />
| .46 5 .3 -25 .6<br />
2.19 9.8-24.5<br />
r.t0 7.6-24.2<br />
2.07 7.4-20.9<br />
0.90 6.6-18.8<br />
0.90 '1.4-24.5<br />
0.54 5.3-25.6<br />
2.68 3.t-20.6<br />
r.o7 |.6-r'7.3<br />
3.45 16.4-39.0<br />
r.42 8.6-31.6<br />
t.L9 4.6-t5.1<br />
r.05 1.8,23.8<br />
1.22 7 .'1-t7 .r<br />
1.00 4.3-27.r<br />
1.41 3.1-39.0<br />
0.64 r.6-31<br />
.6<br />
As with the density experiments, minimum and maximum sizes were used<br />
as indices of performance. As cach clutch was uscd in only two lreatments<br />
(11 m2and 5.1 m2), thc highesr maximum and highcsr minlmum ZoHL,s and<br />
TrTL's were coded as "1", and thg lowest as '0", for each clutch. Thcre was thus<br />
a maximum value of 4 that could be allocated to any clulch on Table<br />
qaHL<br />
26; 2 for<br />
and 2 for 7oTL. When summed, .he rcsutts in;icated a marked bia; (Table<br />
27)(contingency. lable, Chi-square = 61.2; DF = 1; p
266<br />
The negalive corrclation can also bc dcnonstralcd by cxamining thc mcan<br />
differences in thc growlh mcasurcs ('/,HL, q.HLf;.;\, q.HLnax, qoTL, %TL11i11.<br />
ToTLmax) belwccn ihc rwo nraximun spaccs tcstcd (1.7 m2 and 5.1 m2)(Tabtc<br />
28). This differcncc in cach oI thc six columns dccrcascd wilh incrcasing<br />
dcnsity (lincar rcgrcssion), but in none was the decrease statistically<br />
significan!; lhus mean valucs werc cilculated. With EaHL and Ea"fL, thc mc^n<br />
differences (1.01 !0.48 and 0.18 40.63) wcrc close to zcro, as expcctcd from<br />
the ANOVA'S above. However both minimum measures (ToHLmin and %Tl-nin)<br />
showed negative valucs (-2.26 t 0.71 and -2.'72 !0.68> and both miximum<br />
values (%Hl-nax and o/aTLm^) showcd posilivc vilucs (3.89 !1.10 and 3.63 !<br />
1 .62).<br />
Table 27. Asscssmcnt oI thc rangcs ol valucs rccordcd on Tablc 25 (mcximum<br />
and minimum loHL's and TaTL's) Ranks of 1 and 0 wcrc allocated to<br />
thc highcsl and lowcst rcspectively for cach clutch. N = thc<br />
number of "highest" values in each maximum space category. (N) =<br />
marimum possiblc scorc for cach ranEc c\tremc,<br />
Space<br />
(m'?)<br />
1.',l<br />
5.1<br />
N<br />
RANCE<br />
Minimum Maximum<br />
Value<br />
32 894/o<br />
ll9o<br />
(28)<br />
25Eo<br />
7 5Vc'<br />
(28)<br />
Tablc 28. Relative advantagesand<br />
disadvantages of small (1.7 m2) and large<br />
(5.1 m2) maximumspacc<br />
as indicaled by the differcncc (5.1'1.7 m,)<br />
in mean, minimum and maximum growlh.<br />
Clutch Density<br />
(m 'z)<br />
F24<br />
A3<br />
D26<br />
Atl<br />
F18<br />
't2<br />
F2l<br />
M5<br />
F7<br />
MRI<br />
R11<br />
7.1<br />
7.1<br />
10.6<br />
10.6<br />
10.6<br />
10.6<br />
l4.l<br />
t4.l<br />
14.l<br />
t'7 .6<br />
r7.6<br />
Mean<br />
t.l<br />
2.2<br />
-0.6<br />
3.5<br />
0.1<br />
,0.6<br />
2.3<br />
-0.6<br />
0.0<br />
1.2<br />
%HL<br />
Min. Max.<br />
- 3.0<br />
-0.4<br />
-4.O<br />
-0.8<br />
1.1<br />
-2.4<br />
,5. 1<br />
0.2<br />
- 1.6<br />
- 1.9<br />
- 1.0<br />
-9.8<br />
?.8<br />
7 .{)<br />
8.0<br />
2.9<br />
6.6<br />
- 1.8<br />
2.6<br />
6.8<br />
0.3<br />
2.3<br />
-4.4<br />
/o'lL<br />
Mcan Min. Max.<br />
- 1.5<br />
3.3<br />
t.2<br />
-0.8<br />
2.9<br />
- 1.6<br />
-0.6<br />
1.1<br />
- 1.8<br />
0.2<br />
-0.1<br />
-5.5 8.7<br />
1.6<br />
-2.6<br />
- 1.3<br />
12.8<br />
7.0<br />
2.8<br />
0.2<br />
-5.',t<br />
-t.4<br />
-4.9<br />
,2.2<br />
-0.8<br />
8.7<br />
-2.8<br />
2.4<br />
6.2<br />
,0.3<br />
-2,1<br />
- 1.5<br />
-7.8<br />
-3.3<br />
-7,4
Tablc 28 continucd.<br />
Clulch Dcnsiry<br />
(m')<br />
D23<br />
B2<br />
Mcan<br />
SE<br />
Mi n.<br />
Max.<br />
17.6<br />
r7.6<br />
O/AHL<br />
Mcan Min.<br />
2.'7<br />
2.0<br />
1.01<br />
0.48<br />
-2.6<br />
3.5<br />
-0.5<br />
-2.26<br />
0.7 |<br />
- 9.8<br />
0.2<br />
Max.<br />
10.3<br />
3.89<br />
1. 10<br />
10.3<br />
a/oTL<br />
Mean Min. Max.<br />
2.8<br />
2.6<br />
-2.8 8.1<br />
-3.4 10.0<br />
0.r8 -2.'t2 3.63<br />
0.63 0.68 1.62<br />
,5.2 -7.8 -7.4<br />
3.3 l.6 r2.8<br />
26'1<br />
Tikcn logclhcr, thc rcsuhs of the maximum spacc cxperimenls arc<br />
consislent with thosc fronl thc dcDsily cxpcrimcnls. Thcre was little variation<br />
in the mcan values, but significant variation in thc cffccts of maximum sprce<br />
on thc range of values, The trcatnrcnts thal gavc thc highest maximum sizes<br />
(5.1 m'?) Savc !hc lowcs! minimum sizes (cncouraging "runting"), and vicc-<br />
One plausible explanalion Ior thcsc rcsults is tha[ "cffcctivc" dcnsity is<br />
sonewhat independent ol thc measurcd density and thc maximum space. In<br />
esscncc, thc tcndcncy of hatchlings to pile or huddle, could mcan that ihc<br />
key variable is the lotal numbcr of halchlings logcthcr in a pcn,<br />
independent of its sizc. Il also secmed possjblc (givcn cxlrcmc clutch eflccts).<br />
lhal thc numbcr of arrinrrls from thc one clutch, in a pa(icular pcn, could bc<br />
significant.<br />
To exaninc thcsc hypothcscs, the clulch specilic inlormalion in Tablcs 23<br />
and 26 wcrc combincd (N = 40), lnd allempls werc nladc to prcdicl growth, xs<br />
indicated by thc six indicss (o/atlLrl'can, a/aHLmjtu q.HLmax, VoTL6g2n, o/oTLr..|.,<br />
ToTLnax) from density (D), maximuD spacc (S). rotal nunbcrs (N1), and rhe<br />
number of animals from a clulch in a pcn (Ns). Simplc linear rcgressrons<br />
were followcd by nrultiplc rcgrcssions sceking thc best prcdiclivc models.<br />
Thcse analyscs indicalcd:<br />
1. lt was not possiblc 10 prcdict ToHlmcan or o/a'lLmcatl from any of thc<br />
var;ablcs, singularly or in combinatior).<br />
2. II was possiblc 10 prcdic! %HLmin rnd /"TLmin from all four variablcs, but<br />
mullipic rcgrcssion analysis indicalcd that it was largcly sharcd varialion;<br />
N1 gave the highcsl R'? and rcndcrcd lhc contribulion of othcr variablcs<br />
insignificant. This suggcsts thal thc c[[ccts of dcnsity and maximum spacc<br />
are simply cxprcssions oI thc 1o1al numbers of animals in a pcn. Thc<br />
regression slopes indicalc that on avcragc, %HLmjrr and ToTLmin dccreasc<br />
by 0.068% ^ d 0.091"/. Ior cvcry addilional animal in a pcn, rcgardless of<br />
actual dcns;tv or availablc soacc,<br />
%HLn\n\ = 16.95 - 0.068Nt:L 3.35 (R2 = 0.19; P = 0.005)<br />
o/oTL^i" = )2.34 - 0.091Nr ! 3.59 (R, = 0.26; P = 0.0007)
268<br />
3- With thc exceprion of D and ToTLmax, ir was possible ro predicr ZoHLmax ano<br />
Eo"fLmax lrom all variables, but muttiple regression analysis indicated that<br />
it was largcly shared varialion. Surprisingty, Ng gavc the highesi R2 and<br />
rendered lhe contribution of other variables, including N1, insignificant.<br />
This suggests that the altainment of maximum size is rclated to thJ srze ol<br />
panicular clutch groups within each pen,. wilh the regression slopcs<br />
indicating that or average, a/aELmax ^nd ZoTL.u^ increaie by O.2.tEo and<br />
0.36% for every additional animal in a clutch group within a pen,<br />
regardless of actual density or available space.<br />
EaHLmax = 23.09 + 0.272N ! 4.07 (R, = 0. 1 4; p = 0.02)<br />
VoTL^u* = 17.35 + 0.367N t 4.97 (R, = 0.16; p = 0.009)<br />
If this rcsult is an anefact due io the large amoun! of variation<br />
unexplained (much of it duc to clutch effects), lhen Nl would bc the next<br />
most significant factor, rendering borh marimum space and density<br />
insignificanl: the slope would remsin posirive tinireasing growrh with<br />
incrcasing total numbers in a pen). previous unpublish;d lnformauon<br />
suggests that clutch rccognjtion within pens of miicd clurches is a reat<br />
phenomenon, and thus we are nol prepared lo discounl it.<br />
A number of conclusions and hypolhcses can be drawn from the<br />
experrments:<br />
1. High effective densities in the lir$ month may be stimulating somc<br />
individuals to become dominant, and they achicve high growti rates as a<br />
consequence. However, it is at the expense of the poor;r performers,<br />
whose low growth rates are rotarded even further.<br />
2. Assessments<br />
based on mean valucs and an asumption of normal<br />
distributions may be misleading.<br />
3. Where a large disparity between maximum and minimum sizes develops,<br />
assessmenls<br />
. based on body weight trarhcr lhan lentLh r could wciAht<br />
.<br />
rhe<br />
maxlmum srzed animats significantl), causing a shift in mean valuis rhat<br />
lgnoreJ Lhc effecrs on the min;mum siTed animals.<br />
4. In'pens where halchlings congrcgare or pilc, ellective density telares<br />
more to the rotal numbers lhan lo \tandard measures of density or<br />
maximum space.<br />
5. The attainmen! of maximum size may be related to the size of a clutch<br />
specific group in a pen.<br />
6. The best strategy for rcducing "runts', in C. porosus within the first monul<br />
would seem to be !o maintain small groups of animals, quite possible n<br />
small pens. A cosr, if nor rccrified by griding, may be ieduced numbers of<br />
very rapidl) growing indiv id uals.<br />
10. Stress in Hatchling C. porosus<br />
Jenny Tunon (James Cook Univcrsiry of Nonh eue€nsland) is engaged in a<br />
scries of,rrials .aimed ar. improvinB our understandiig of rne retati;nllip<br />
ocrween husbandry pract'ces. srress, immunity and disease susceptibility in<br />
C. porosus hatchlings. The research ro dale has involved rcDealed blood
sampling of hatchlings mainlaincd in pens with waler at 320C, but then<br />
switched for va.ying periods inro pens with water at 28oC and 36oC. Blood<br />
samples are being analysed for conicosteronc levels, which indicate srress,<br />
and both leucocyte counts and immunoglobulin levels, which indicate<br />
immune funcIioD.<br />
11. Growth Hormone<br />
In 1990, three clutches of C. porosus hatchlings were used for preliminary<br />
experiments evaluating the effects of recombinant growth hormone.<br />
Animals from each clutch were dividcd among 4 pens within the one tank,<br />
and subjected to thc following treatments, which were allocatcd randomly 10<br />
the pens:<br />
l. Injected wift growth hormone and measured every 2 weeks<br />
2. Injected with saline and mcasured every 2 weeks (sham)<br />
3. Handled and measurcd every two weeks (Conlrol 1)<br />
4. Measurcd at beginning, and at end only (Control 2)<br />
Recombinant porcine (pig) growth hormone was injected every 2 weeks<br />
for 12 weeks (i.e. 6 injeclions), at a rate of 2 p"g per g of body weighr. Animals<br />
in the saline treatmenr were injected wi|h an equivalent volume of saline.<br />
They were injccrcd through thc axillary region into the body cavity, using<br />
fine gauge ncedles.<br />
The results (Table 29) indicale obvious clutch effects on growth, which<br />
were highly significant (ANOVA; P = 0.0001). There was no effec! of<br />
treatment between hoamone and salinc. nor between the two controls<br />
However, thc conlrols wcre significantly different (reduced growth) from<br />
both hormone and saline treatmcnls (ANOVA; p = 0.02). The reasons why the<br />
controls showed reduced growth relative to the saline treatment are unclear.<br />
Although no significanr difference bctween means was apparent (Table 29),<br />
minimum growth rates were consistently larger with thc hormone trealment<br />
than with the saline lreatment; maximum growth rates were not. Amongsl<br />
the iwo controls, rhose with thc least handling (Conrrol 2) gave consist;nlly<br />
better growth in terms of means, minimums and maximums, although the<br />
variation was such Ihat ir did not reach significance.<br />
In 1991, mini-osmotic pumps wcre implanted into two groups of<br />
hatchlings to provide a continuous output of solution. These pumps released<br />
recombinant porcine growlh hormone (0.1 pg t!l-l) into one group, at a rate<br />
of 0.39 pl h_1, and saline into rhe other. The toral dosage was approximalcry<br />
llo/a of the lotal dosage in 1990. The pumps used were cylindricat (? mm<br />
diameter), rounded at the ends, 30 mm long and weighed 1.1 g. To implant thc<br />
pumps, a small incision was made in the animals' sido, towards .rhe back legs,<br />
and the pumps inserted under the skin; the incision was then stirched. A<br />
control group werc nor ireated in any way. All animals wcre weighed at 3<br />
and 6 wceks of age (Table 30). By approximarcly 20 days thc homone willin<br />
thc pumps would have been depleted.<br />
The pumps remained in place until lhe 4th week, when some staned to fall<br />
ou1. This was allowed to continue until after the measurement at 6 weeks,<br />
when.any remaining pumps were removed, No infection was noted on any<br />
hatchlings as a resul! of thg insenion of the pumps at any slage of lhe<br />
experimcnt, or aler rhe experimcnts. Thc study indicated that osmotic purrps<br />
can be uscd in crocodilians, allhough smaller pumps (now available) would<br />
269
270<br />
have been preferable for hatchlings.<br />
Tablc 29. Pcrccntagc increasc in hcad lcngth ('/.HL) lor C. porosus<br />
hatchlings lrom dilTcrcnl clulchcs injcclcd with growth hormone<br />
cvcry two wccks, ovcr a 12 wcck pcriod, aflcr halching. 'Control l'=<br />
hatchlings mcasurcd every 2 weeks; 'Control 2'= hatchlings<br />
measur€d at bcginning and end of experimeDts only.<br />
Treatment Clutch N ToHL SE Rangc<br />
Hormone<br />
Saline<br />
Control 1<br />
Control 2<br />
Hormone<br />
Saline<br />
Conlrol I<br />
Control 2<br />
Hormonc<br />
Saline<br />
Control I<br />
Control 2<br />
Hormonc<br />
Salinc<br />
Control I<br />
Control 2<br />
F40<br />
F40<br />
F40<br />
F40<br />
45l<br />
A5l<br />
A5l<br />
A51<br />
M4{)<br />
M40<br />
M40<br />
M40<br />
ALL<br />
ALL<br />
ALL<br />
ALL<br />
6<br />
6<br />
6<br />
tt<br />
6<br />
6<br />
6<br />
6<br />
6<br />
t2i<br />
18<br />
Itt<br />
l8<br />
3 3.8<br />
27.9<br />
30.4<br />
49.3<br />
48.4<br />
41.3<br />
45.3<br />
52.0<br />
43.0<br />
40.1<br />
42.1<br />
45.0<br />
42.3<br />
36.6<br />
39.4<br />
3.30<br />
2.69<br />
7 .91<br />
2.61<br />
4.21<br />
4.33<br />
2.45<br />
4.04<br />
2.02<br />
4.54<br />
3.05<br />
3.60<br />
2.65<br />
2.49<br />
2. 18<br />
2.45<br />
26.t-47.4<br />
23.9-4r.1<br />
18.7-38.9<br />
19.9-38.4<br />
36.4-60.6<br />
36.1-62.6<br />
33.0-51.1<br />
33..+-57.0<br />
44.5-56.6<br />
33.4,64.4<br />
30.3-52.3<br />
32.9-58.2<br />
26.1-60.6<br />
23.9-64.4<br />
18.',7 -52.3<br />
19.9-5 8.2<br />
The rcsulls showcd no signilicant diffcrcnces berween trcatmcnts, nor<br />
between clulches. The hormone consistcntly rcsultcd in larger minimum<br />
sizcs than !he saline lrcatnlent. Tn contrasl. thc maximum sizes were<br />
gcncrally largcr with thc salinc trcatmcnl than wilh thc hormonc<br />
lrcatment. The reasonably good performancc of controls in expcrinent 2,<br />
relative to both hormone and saljnc trcatmcnts, probably indicates advcrsc<br />
cffccts on growth rcsulting from the surgcry and handling of animals in<br />
both hornlone and salinc trcalmcnts-<br />
Overall, thc rcsults of our expcriments do not show thc dcfinitive growlh<br />
advantagc rcporlcd by Andcrsen ct al. (1990) for C. ,il.rrlcrs juvcniles<br />
injected with recombinant human growth hormone. However, diffcrcnccs in<br />
dosage (they used ?.5 t;mes thc dosc) and frcqucncy of injection (twicc -<br />
week vcrsus oncc each two weeks) may be involvcd. Our rcsults did suggesl<br />
that the hormonc lreatmcnt may bc posilively affccting rhc animals wirh low<br />
growth rates. In this rcgard, lhey suppofl Andcrscn et dl. (1990), who<br />
suggcstcd thal stunlcd individuais may sulfcr from low cndongenous growth<br />
hormone levcls. Clcarly, changcs in thc dosagc and frcqucncy of injeution<br />
may aller the general rcsponse of C. porosus hatchlings 1o thc hormonc<br />
lrcalmenr, and expcrimcnrrri,rn is (onrinuinE.
Table 30. Pcrccnlage increase in head lenglh (SaHL) lot C. porosus<br />
halchlings from diffcrenl clutchcs implanlcd with osmolic pumps<br />
(releasing growth hormonc or saline). Animals wcrc mcasurcd al<br />
halchinp and afler 3 and 6 wccks.<br />
Trcatment Clutch N Agc a/"HL<br />
(wccks)<br />
Hormone<br />
Saline<br />
Control<br />
Hormone<br />
Saline<br />
Control<br />
Hormonc<br />
Saline<br />
Control<br />
Hormone<br />
Saline<br />
Control<br />
Hormone<br />
Saline<br />
Control<br />
Hormone<br />
Saline<br />
Control<br />
R14<br />
R14<br />
R14<br />
M4<br />
M4<br />
M4<br />
ALL<br />
ALL<br />
ALL<br />
R14<br />
R14<br />
Rt4<br />
M4<br />
M4<br />
M4<br />
ALL<br />
ALL<br />
ALL<br />
7<br />
'1<br />
1<br />
6<br />
o<br />
l3<br />
13<br />
l3<br />
'7<br />
7<br />
7<br />
6<br />
6<br />
6<br />
3<br />
3<br />
3<br />
3<br />
3<br />
3<br />
3<br />
3<br />
3<br />
3<br />
3<br />
3<br />
6<br />
6<br />
6<br />
6<br />
6<br />
6<br />
6<br />
6.J<br />
7.3<br />
8.1<br />
9.0<br />
7.6<br />
8.8<br />
8.8<br />
7.4<br />
a.)<br />
13.4<br />
13.7<br />
14.6<br />
13.3<br />
16.0<br />
14.0<br />
14.8<br />
SE Range<br />
0.60<br />
0.84<br />
0.45<br />
o.44<br />
1.07<br />
0.43<br />
0.37<br />
0.64<br />
0.32<br />
1.09<br />
1.69<br />
0.98<br />
0.63<br />
0.91<br />
0.65<br />
ACKNOWLEDGEMENTS<br />
6.2-t1.1<br />
3.9,10.3<br />
6.2 9.8<br />
7.8 - r 0.9<br />
3.5-l 1.5<br />
7. I - 10.0<br />
6.2-11.1<br />
3.5-11.5<br />
6.2 - 10.0<br />
8.2-1"/.3<br />
6.2-18.2<br />
9.2-16.',t<br />
0.51 12.2-15.8<br />
0.57 11.4-14.7<br />
0.54 14.9-17.9<br />
8.2-17.3<br />
6.2-r8.2<br />
9.2-17.9<br />
Many individuals have contributed directly to thc rcsearch discussed<br />
here, particularly David Ottway, Sharn Daly, Stuart Barker, Rebecca Bakcr,<br />
Akira Matsuda, Mario Orjucla Castro, David Clark and Boyd Simpson. We would<br />
like to thank rhc following people for providing summaries of their<br />
findings: Roger Scymour, John Bald)vin, Bill Runciman, Ruth Bcllairs, Jenny<br />
Tunon, Pctcr whitehcad and Gregor Riese. Funding of our research was<br />
provided primarity by lhc Conscrvation Commission of the Northcrn<br />
Territory and G. webb Pty. Limilcd. A variely of olher Universities and<br />
establishments funded collcagucs aDd other research summa scd here. Matti<br />
Ufictt and Craeme Davis have been instrumcntal in maintaining the<br />
Conservation Commission's intcrcst in crocodile research.<br />
211
2't2<br />
BIBLIOGRAPHY<br />
. Wift the exception of p.pers and reports markcd (*), which are retcrred<br />
lo rn the rext, lhe following publications (1990 to mid_1992) arc based on<br />
work carried out in rhe Northcrn Territory, mosrly with CbNT assistanse.<br />
*Andersen, O., Kimwele, C., Amfin, A. and Kanui, T. (1990). Effecrs of<br />
recombinant human growth hormone in juvenile Nile <strong>Crocodile</strong>s<br />
(Crocodylut niloticus). Comp. Biochem. physiol. 97 At 60'l -g.<br />
*Bennett, A.F., Seymour, R.S., Bradford, D.F. and Wobb, G.J.W. (19g5). Mass_<br />
dependence of anaerobic metabolism and acid-base disturbance dunng<br />
aclivity in the saltwater crocodile, Crocodylus porosls. J. Exp. Biol. llgi 16?-<br />
*Carmel, B.P. (1221). U_se<br />
of oxyrocin r(j inducc oviposition in a dysrocic<br />
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*Caughlry G. (1980). Analysis oI Venebrare populalions. John Wilcy and<br />
Sons: New York.<br />
*CCNT j1989). A m,anagrmcnt prog'am fot Crocodrlus porosus andCrocod!tus<br />
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D arwi n.<br />
*Georges, A. (1989). Female turllcs from hot nests: is ir duration of incubation<br />
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crocodilians. /n A Directory of Crocodilian Farrning Operations, c-d, by R.<br />
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Producrion Seminar. Townsvillo, 7-8 August 1991. Depr. prim_ Ind.:<br />
Townsville.<br />
Manolis, S.C-, Webb, c.J.W., pinch, D., Melvilte, L. and Ho[is, G. (1991).<br />
Salmonella in captive crocodites (Crocodylus johnstoni ani C. p"lror"O.<br />
Aust. Vct. J. 68: 102-5.<br />
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Lrocodytus porosus in the ridal waterways of northern Australia. ,4/lsr.<br />
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jmplications.<br />
manaeemcnt<br />
Pp. 189-a8 in Witdlife Management: Crocodilcs ind<br />
Alligarors. ed. by C.J.W. Webb, S.C. Manolis and p.J. Whirehead, Surcy<br />
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1]ry wet' scason and stalus, managemcnt and recovery. pp. 23i-306 an<br />
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Cland, Swirzerlana-<br />
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lhe.Sratus<br />
anO<br />
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A4ernoos tor Anatysrs. and Dynamics of a population ol C. porosus.<br />
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*Riese, G. (1991). Facrors influencinS rhc survival and growrh oI harchling<br />
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-Unpulfisr,"j r.,rS"<br />
(Qualifying) Thcsis, Univcrsiry of euccnsland. gris6ane-<br />
'<br />
*Seymour, R.S., Bennctt, A.F. and Bradford, D.F. (1985). Blood sas rensions and<br />
acid-base regularion in lhe salFwarer crccodite Crocodyln, |iriii", o, ,.",<br />
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ur<br />
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" ""<br />
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rcmperaturc<br />
ellecrs of<br />
on sex determination and embryonii develoDment rate<br />
Ctocodylus johnst.oni<br />
rn<br />
ard C potosus. pp. 507:31 ; t;ilii:i. ;"na.e;*"rr,,<br />
lrocoo es and Altlgators, cd. by C.J.W. Wcbb. S.C. Manolis and p.J.<br />
wnrrcneao. Jurrcy tscally and Sonst Sydney.
ai1<br />
'r'rr'rnb.<br />
al i.'! . il,rc.woiL!,. ,l<br />
rirr r,lcKln{Nv iiivc: rr:f<br />
'<br />
.,,r iriis. S.C. !\t:ta):. Cro.odt'in.i john.\to/ti ;t<br />
' :'1rr!r Sioiog)/. r\{rs1. !]/i1C!. P..i l0: 607-37.<br />
..!.'r.bb. {l.r ,! ;ir(t a,1iuoc..rr",_.. :iir rr irir). ef]ccLs oi rncubiii,,r,<br />
I :'ncf:irrrc lrir ,rir|t)nrir! ;:'r<br />
ci aai:llia! 1r"!airiiv t\m.<br />
",),.rlic1r<br />
,i,'.;. :,. !,il-rr.<br />
:'!-!^i-rb. ;: J.!\i.. ]';illon. i .-. i. ci-.:i r.i;.. ,-artoirs. !.C. ii,,!1 ll.r,c,. i. r. il;:,Ob.).<br />
,'1-rllioring ilir :r:ilviucf I rr'._ri rr'. -':)ro?!lus ro.a!t4s)'roDuialion rr hc<br />
'i,iilhern :irririory lf : iistriiiii.<br />
',i- -: '!-ilo ia :-'r'oc<br />
"1'r worklng ./lcelrns<br />
l!,N-SSL' Crcc.dile .l'.cc:iriisis a: ioritr r-;r!, ::TDua .'jc.v ,.ruinca ::.1':r :.l.l1rrf"<br />
illlill. :!CN PND!.: : l-r :r', .. - rrr.<br />
,:,i1.t0. ii.r."/ . .lclll!. .l...<br />
r,f ..r. ri ... ,..a, i',1.;.' I<br />
,r:r, r,-f::1.ir ;r'ilis r,i<br />
't),"a!t:t,t<br />
i l. :..:.ttt:l.i): . ':,a ,\i.: ' '<br />
ijjt.<br />
.r,ri;:. ,: .\r',i! ..n,, li.(io<br />
.'.1:i-r.,,. : ;s .'<br />
a/ r ir!.,ir,.n, _l |..,,j,;,i1]]i.<br />
..!i r:.,r , r :r,lr ,r'rr-<br />
rV!lc. aj.j.li. aiLi ,'lijirolir, :1.4. tlr":) a:',Jeoelli ';iirr:i! - f.:eri!i: ir:rr,r1rti,.<br />
Pp. 256')65 ln P.o!. lr1,:r)ti'!: 'iro.,.ill Afiirf' P.fd!,.riorr 5'rrrilr.r1.<br />
l'ownrv;i1., 7li A!!,rst 19t,. :lqri F'lJr, lrd.r 'i.!,:s/l:i..<br />
Wcob. C.J.W. and Marolr. :j.{1. ili(,:1. Ir:crirrrirr! s1i1\rirlcr !rorodilcs<br />
lCrocodylus /,..)/ririr) ;n ri,; li.rlli.rir Tcrfilor) oi Auslraiia. -/, Pro'-<br />
"Wildiitu 2001 ' Confcrcncc. O.i.i(l.r1r{rs. California" 29-31 July 1991. lin<br />
\"v'cbb, c.J.lV., M!nolis. s.C. ard Cooncr Frcston, ]1. (ltti)!). Crocodilc .escarch<br />
end nranagcncnl in 1hc Northcrn Tcrrilory: l9Bll-90- Pp. 253 73 tn Proc.<br />
10th Working Mceting IUCN-SSC <strong>Crocodile</strong> Spccialisls <strong>Group</strong>. Cttincsvillc,<br />
irlorida, 2,:-2? ,^pril 1990. IUCN Pubi.: 6lano, Swilzeriand.<br />
tWcbb, C.i.W., Itanoirs. S.C.. \'./lrrcncaa, P. and Lcrls. i;.,1954). L proposJr ;or<br />
ric rransfcr of thc Australill populalion oi C/ocodtLus porosur Schncidcr<br />
il80l), arorn Appcnsix t to /\Dpcnoix 1l of C.I.T.E.S. Cons. Comm. N.T. Tcch.<br />
Rcp. No.21.<br />
*Wcbb. G.J.w. and Mcsscl, H. (19711). Movemcnl and dispcrsal pattcrns of<br />
Crocodllus porosus in somc rivers of Amhcm Land, norlhern Australla.<br />
Ausl. wildl. Rcs. 5: 263-83.<br />
wcbb, C.J.w. and vcrnon, B. (1992). Crocodilian managcmcnt in thc Pcoplc s<br />
Republic of Chinll - a rcview wilh rccommendelions. Rcportro<br />
IUCN-SSC<br />
Crocodilc Spccialist Croup.<br />
whitchcad, P.J. (1990). Yolk deplclion and melabol;c rate oI<br />
Crocodtlus johnstoni. Copcia 1990: 871 5.<br />
halchling<br />
whilchcad, P.J. and Scymour, R.S. (1990). Paltems of metabolic rate in<br />
embryonic crocodilcs. CrocodJLus iohnstoni and C. /o/ojtJ. Physiol. Zool.<br />
631 334-52.
Whitehcad, P.j., Wcbb, C.J.w. iind Scymour. R.S. (1990). Ellccls ol tncubrtion<br />
lcmpcrafurc on Srowlh and dcveiopncnt |ar.!t of Ctocodtlus johnsttni<br />
embryos. Plrysiol. Zool. 63(5), 94941.<br />
whilehcad, P.J-, Wcbb, C.J.w. and Scynrcur, R.S. (1992). Encrgelics ol<br />
embryonic dcveloprncnt in Crocod!lus johnstonit rslalion 1() duralion of<br />
incubalion. Physiol. Zool. 65: 360 78.<br />
z'7 5
2',16<br />
Artificial Incubation of saltwater <strong>Crocodile</strong> (Crocodylus<br />
porosus) Eggs<br />
D.w. tlilken, H.A. Staton, B,P. vernon, and B. Bon<br />
Mainland Holdings crocodi le Farm<br />
P.o. Box 19{;<br />
Lae, Papua New Gu i nea<br />
Three experiments were conducted to detormine the influence<br />
of incubation parameters on hatching success and the<br />
unifornity and pErformance of hatchling saltwater crocodile<br />
(Croaodylus parosus). In experiment f, eggs from 17 nests<br />
were incubated in a walk-in. commercial incubator at 3l ,7oC-<br />
Eggs from each nest were divided ihto tlto or more groups of<br />
12 or more eggs, and these groups tere randoml y allocated to<br />
one of four treatment groups (either "wood wool" or natural<br />
nest material as Lhe incubation substate; vrith e99s either<br />
covered or Lrn( overed dur i ng incubat ion ) . Between-nest<br />
differences in hatchability were statistically significant,<br />
However, even with this variabi I ity accounted for,<br />
differences in hatchabiliLy due to treatment (75.6-82,9x)<br />
were not significant. fn experiments II and III, 105 e99s<br />
from three nests were incubated at 31.O. 3l.7 or 32.4oC.<br />
Incubation pe|iod ranged from 78-79 days for eggs incubated<br />
al 32.4oC to 85-92 days for eggs incubated at 31.OoC.<br />
Hatchability averaged 90.5* over the two experiments, and<br />
was not 6ignificantly different between treatment groups.<br />
At higher incubaLion temperatures a greater percentage of<br />
eggs hatched naturally (e.9,, wjthout assistance). Over the<br />
range of incubation temperatures in the6e trials, posthatching<br />
growth rate was greatest for hatchlings from e99s<br />
incubated at the higher incubation temperature.
'rrfr<br />
EFFtcls 0F cRoppllrc o AxERlcA ALttGAr0R popurAiIof{s<br />
It{ rLoRt0A, u.s.A. I<br />
by Al 'an P. lrscdyard, Cljrtrn T. tioofe, Uichaol nelarJT,<br />
anC Trony C. Hj ne::<br />
Flarida Ga$e and fresh Water Fish Co|nnisston<br />
4005 South i3rn $treet<br />
Geinesvilje, tiorlda,J.S.A.<br />
27',1<br />
Abstrait'-Arr rxperim€ntil harvest cf conmercjal-sjze (:11?-cm) An€rican<br />
8lligato.9 {.4iligntor rissis,"ippigrsis) has conduateC on t.eatrlent areas.<br />
Lochlcosa,orarge, and ewn!fts lal*s in northcentral Florida dtri|1g 19Bl-90 3nd<br />
response to h6!'vust v,as conFared ivith ccnt!"o] afeas pnynes p!"airi9 and Lake<br />
*oodrrff. An ovefall oeal) of 13yr \{as harve:ited nnrLtally but thjs vdiied i;lightly<br />
Dy area. Ihe fiBijj an total iength (-IL) of harve$ted all igatcrs ,a.ied by a!.€a and<br />
gnal14r alljgators congtit te$ an increaslngiy greater p.opofticn of th; harve$ts<br />
c';er yetrs. Ihe horvest bras p.eCoDrjnartiy (69.gjl) male. incieased huntsr etfort<br />
i'las tece953t'y over yeaas tc nai tain slccess fates beca!se of Dn l'lcrease tn<br />
!.Jtri ness of laager alljgdtors.<br />
lJo changes rvere C€terted in the physjcil cooditi0n of ha.vegted alligators,<br />
Njght-'!ight cou.Jts of r,arvestable alligators .eirained stable on alj harvest and<br />
control aress, but sone evidence of derlining counts of adult ().!93 cn)<br />
alliSntors was dete.ted cn lakes ofa'.'gp {-45'bj, Lochloosa (,6:JS), and *oodrlff<br />
(-lB%), Declines rsre attribut-ad prjma.ily lo r]arjness from h(]l!ting and livecaptor€.<br />
Colrts ol juveilile alligetors increased otr Crange and Lochlocsa lakes,<br />
Nest prodrction was lllostly jr,fluenced hy May and Septefiber water ?evels aod<br />
re,nained stable oir all areas except orange ,-ake ar,d Lake Wocd.uff whefe nesi.ing<br />
jncreased. Hest sl-rrvival ircreas€d d0ring the study, prioari 1y due to decreasing<br />
jncidence of flocalin0. ,,lest p.edaticn iras attriblted tr raccoans and !/as<br />
g:"eatest 6n o.ar$e t.ake i51%).<br />
Clqt0h si?e Cistrjbutjons varied aftono areas rjirrpled (0range L.ak€, paynes<br />
Prairie, and Lake $crdr!ff' and medr! c?utch $i.e on Lake Woodrxfi f42,9) lvas<br />
greaier than thaie ot Crra^ge i-axe {32.8} and PeynEs prairie<br />
{33.8i_ Clutch size<br />
drd,rot chante ovor years Or eithe. treatrlani or contfol a.ea5, lri,1idum siie at<br />
oaturrty i{as J80.5 r& for an orange Lake fesale but only 64!t, of >J83 cdt feF,iles<br />
were liat{lre, PrOpO.liDns of;ratur€ fe'n3les ai ., tiven s.jre class v;ried by aaea<br />
'.rith flewnarG ia'(e lenales aat!ring at a greater siie, paopDrtion of nature<br />
fenal-As ovulating did not change cver years but d6s less on Newnans {15,9S) than<br />
eiiher j-ochloosa {38-srv") or o.aoge Lake (3$.8%j.<br />
The langest al'ligator recordrd cn study lakes f!.on 1gBl,g0, an Orange Lake<br />
nale, wag 423 crn TL and 473 kg. The largest fenale, taken on O.ange Lake, was<br />
297 ch and 115.5 kg. Skbad!]t (122-19, crn) all igators 0rew t,rster on t.ochloosa<br />
atd flervoafls than they did on drange and yloo,-jruff lakeo, Fsti ated years fcr<br />
f-6rhales to,-eath ri'|,in m rEprodrcl.i ve sire (180 cft for Lochlcosa anC O.ange, and<br />
21 I cin for Nelvnans) ranged f.o'! 8.9 on Lochloosa to 12.4 on Ot.ange_ Markrecapture<br />
data and feaur annr)i analyses indicated that grolrtl, .ates cf females<br />
j<br />
Presentedat<br />
the 11th Worki|19 MeEting of the Croccdile <strong>Specialist</strong> <strong>Group</strong>,<br />
Vi ctori a Fal i., ;iqbabwe, 2-7 August, 199?.<br />
2 Presefit Address:<br />
ficlte J, 8ox 509, Newberry, Flo.jda, U.S,A
278<br />
did not chnnge tufi09 ths hrt"Je:!r- but tirat grotri h rate-< c{ thE Frbai{r'lt r'ale:l<br />
1t;.e.!5ed.<br />
]4e fclid nO evjceqae tjlat 3lj,igatcrs frarveFts afigcled fish Foprlaticrs or<br />
n!trten: levels ir iares. Lra!i ight risjht lit!. af rlligatcr"s dr!i-';'.d j4t,i9di119l!<br />
afte,- hlnts bllt reccvered f!jli.by the follcwing yearj siJggestjri'iiit hiryests<br />
htd rrnly a tedporar!, effrcl rr daylj.Jht vjeirrn! ci alligatcrg.<br />
A s!slsrneil 13ql proportr.rnnl ha!_',9st cf ao*inarcial -ci:e nlliSatorr haC rlu<br />
fieas{Jrable negative a{feats on elligntor populatjons. Diffp!.ence! aocr!1 gtuly<br />
areas in resporsg 9t deilDgriphir ira.am|)ters to hafvest tndilate that ,etlaFds<br />
with dissiniiar denogfapl-"r.s ftay respond differently io harvr5ts.
...: ..<br />
''rli i.. :l:i:r_ri-1<br />
I ,r ,.,.:.,ri ,:j rj.r,;,, 1<br />
a:r. r' il,:l : :!.<br />
.,r:li:ll,nf: i<br />
! 0 ii!:\ i - f :r.-''<br />
'Iil.<br />
i,lir.:s*,e<br />
i r:.rl!a l|] /<br />
f:A<br />
.ABEflCRONI6iO A'<br />
ltofroni Colleg.€<br />
jpaitanDury<br />
South Camlins 29303<br />
{JSA<br />
BARRETT J<br />
c/oPOBox636<br />
CsDberra<br />
ACT 2601<br />
Austmlia<br />
BEHRA O<br />
Biod€v<br />
Irt VX lE Andr€frndrova<br />
Anta nana rivo<br />
MadlgFsctr<br />
r! ir".); .; :::<br />
:':.':,:.:,<br />
inlrrf<br />
:ii:lrrrdrlr<br />
;iiiibai)*e<br />
:IROWN K<br />
Z;mbrow€<br />
CALLOW R<br />
P O Box 191<br />
Har:tre, Zimbahw€<br />
( \wooD B<br />
Private Bag 5730<br />
B€it Bridge<br />
Zimbabwe<br />
cocK E v<br />
15 Knowetop Drive<br />
Grc€ndale<br />
Ha*rre<br />
Zimbabwe<br />
cll-ql]HouN I<br />
F D 8ox i30<br />
iriorton<br />
Zlmbabld€<br />
:,1'rj<br />
'TILISES P<br />
? 0 Aox 39E6<br />
Pi€t€rsburg<br />
lepublic of South Africa<br />
c'J;:i ti<br />
? I) .3r,;t 53i0<br />
,.1.r:"rs<br />
'at'a!irr:r5ran!<br />
,'rtli:!rll.r ,18 il<br />
aati ;<br />
rr 6l\0<br />
? C llor 2-333<br />
./ricrrld<br />
:lrdonesia<br />
CRA1G C<br />
62,4 Nilpier AY€nue<br />
HiUs;de<br />
Sulawayo<br />
Zimbabwe<br />
DACEY T<br />
P O Box 40617<br />
Crsuarina<br />
No hcrn T€rritories<br />
Australia 0811<br />
DA\'ID D<br />
716 NW 97 Tierr<br />
GaiDesville<br />
FL 32607<br />
USA<br />
DAVIS G<br />
P O Box 42092<br />
Casuarira<br />
Northern Ter tories<br />
Australia
280<br />
DENLE"T M<br />
Coixs Postal 239 Cep<br />
9 Osodo RS Brazit<br />
DORE M<br />
PMB 21198<br />
Ikeja, Irgos<br />
Nigeria<br />
DRYDEN D C<br />
P O Box 191<br />
Ilarrrt<br />
Zimb.bwe<br />
EDWARDS S<br />
IUCN 14m l6rh St Nw<br />
WsshiDgton<br />
DC 20036 USA<br />
EII)BEID A M<br />
Wildlife Cons€rvation<br />
P O Box 336<br />
Khartoum<br />
Sudan<br />
ELSEY R<br />
Rouie 1, Box 20D<br />
Grard CheDier<br />
Iruisiarna 70613<br />
USA<br />
ERIKSON A<br />
P O Box 559<br />
Oudtshoorn<br />
Cspe Province 6620<br />
Republic of Soutl Aftica<br />
EVANS P<br />
P O Bor 3214<br />
Quito<br />
Ecuador<br />
FERGUSON M W J<br />
Dcpt Cell & Structural<br />
Biolo$/<br />
Univerfity of Monchesacr<br />
Stopford Building<br />
Oxford Roed<br />
MaDchester M13 9PT UK<br />
FERGUSSON R A<br />
CFAZPOBox55<br />
lGriba<br />
ZiEbabwe<br />
FERNANDEZ E<br />
Finca Chojoja<br />
Mszatetrsngo<br />
Suchitpeques<br />
Guatemala<br />
FINCHAM J R<br />
Archosaurir <strong>Crocodile</strong> Farm<br />
P O Box 260<br />
RaDsgate 4285<br />
Rcpublic of South Africa<br />
FOOT C<br />
P O Box EH29<br />
Ernerald Hill<br />
Harare<br />
Zimbabwe<br />
FTILLER M<br />
P O Box 6870<br />
Tallahassee<br />
Florida 32314, USA<br />
GAMES I<br />
P.O. Box U.A. 296<br />
Harare<br />
zimbabwe<br />
GENOI,AGANI J<br />
Natiorlal <strong>Crocodile</strong><br />
MaDagemena Uria<br />
D€partmena oi Envimnment<br />
& Consenation<br />
P O Box 6601<br />
Bomko NCD<br />
Papua New Guinea<br />
GIBSON D<br />
624 Napier Avenue<br />
Hillside<br />
Bulawayo<br />
Zimbebwe<br />
}IALLDR R D<br />
Baobab Farm Ltd<br />
P O Box 90202<br />
Mombase<br />
KeDya<br />
HALLER D T<br />
Baobab Form Lid<br />
P O Box 90202<br />
Mombasa Kcnya<br />
HEMLEY G<br />
Traltrc USA<br />
1250 24th Sa Washington DC<br />
20037 USA<br />
HEONC Koh Chootr<br />
50 Detu Lane 7<br />
Singapore 1953<br />
HIBBERD E M A<br />
Biolo$/ Depsrtment<br />
University of CeDta I<br />
Queensland<br />
Rockhampton 4700<br />
Australia<br />
HINES T<br />
Route 3 Box 509<br />
Newberry<br />
Florida 32669 USA<br />
HOQUE E<br />
155 Ho$l€y Road<br />
Panania NSW 2213<br />
Australia<br />
HOOGMOED M<br />
Nationaal Natuuftisaorisch<br />
Museurn<br />
Postbus 9517<br />
2300 RA Leidcn<br />
Netherbnds<br />
HOPE C<br />
Dept of Sociolos/<br />
C.oll€ge of Charl€ston<br />
Charleston<br />
South Carolina USA<br />
HUCHZERMEYER F W<br />
P O Box lA99<br />
Ond€rstepoort 0ll0<br />
Republic of South Ahica<br />
HUNT H<br />
Atlafis 7^o<br />
800 Chemkee AveDuc SE<br />
Atlanta GA 30315<br />
USA<br />
HUNTER I<br />
P O Box 417<br />
Mamndera<br />
Zimbabwe
HUTION J<br />
CFM<br />
POBoxHGll<br />
Highlands<br />
Harare<br />
Zirnb{bwe<br />
IMWUTIKUN W<br />
Wesao <strong>Crocodile</strong> Farm<br />
121 Mou 3<br />
Malsm Tao<br />
w't Singh<br />
Chsinart<br />
Thailand<br />
ISHII N<br />
4"7.10, Nihonbashi Honcho,<br />
Chuol<br />
Tolryo<br />
Japrn<br />
JELDEN D<br />
Mallwiazstr, 1-3<br />
531X) Bonn 2<br />
Germany<br />
JENKINS R<br />
ANFWLS<br />
P O Box 636<br />
Csnberra<br />
acr 2fi1<br />
AUSTRALIA<br />
JOANEN T<br />
Rorrae 1 Box 20-B<br />
Grand Chenier<br />
I,A 70643 USA<br />
JOUBERT J<br />
P vste Ba8 3<br />
Buhrmannsdrif 2867<br />
Republic of South Africa<br />
JOUBDRT B<br />
Priv.te BAg 3<br />
Buhrmannsdrif 2867<br />
Republic of South Africa<br />
KELLY H R<br />
Rive$end <strong>Crocodile</strong> Farm<br />
PO Box 2"45<br />
Ramsgete 4285<br />
Republic of South Africs<br />
KELLY T J<br />
Riveniew <strong>Crocodile</strong> Fa.m<br />
POBox<br />
Wartburg 3450<br />
Republic of South Africa<br />
KENNERLEY D<br />
Dwangws Sugar Corporation<br />
POBox46<br />
Dwengwa<br />
Malawi<br />
KOCHEN R<br />
Guadrh 5 Casa 15 ' Jardim<br />
Petmpolic - Cuiaba . Malo<br />
620550<br />
Brazil<br />
LANCE V<br />
9925 Mozelle l,ene<br />
L Mesa<br />
California 91941<br />
USA<br />
I,ANDREY<br />
P O Bor 87416<br />
Houghton<br />
Johannesburg<br />
R€public of South Africa<br />
I"ARRIEM A<br />
Bu. Pell€gdni 3700<br />
3000 . Santa Fe<br />
Argentina<br />
I"ARSEN M<br />
Crookes Brothers Ltd<br />
P O Renishaw 4181<br />
Republic of South Africt<br />
LELLO J<br />
P O ReDishrw 4181<br />
Republic of South Africa<br />
LEON A<br />
P O Box 240956<br />
Bogota, Colombis<br />
South America<br />
LEVER J<br />
Koor€na Crocmdile Fsrm<br />
MS 76 Rockhampton<br />
Queenslrnd 4702<br />
Austnalia<br />
LOKJH<br />
P O Box 420<br />
Bulawsyo<br />
Zimbabwe<br />
287<br />
LOVERIDGE J P<br />
Univc$i1y of Zimbabwe<br />
P O Box MPl67<br />
Harare Zimbabve<br />
LOWE C<br />
c/oPOBox185<br />
Victorie Falls<br />
Zimbabwe<br />
MARAIS J<br />
Pdvaae Bag 3<br />
Buhrmannsdrif 2867<br />
Republic of South Afri:,<br />
MENGHI O<br />
CITES<br />
6 Rue Du Maupas<br />
1000 I-ausanne 9<br />
Swiazerland<br />
MDSSEL H<br />
CIIAIRMAN CSG<br />
l2AC Hope$ood Gdn<br />
13 Tholnton St<br />
Darling PT<br />
NSW 2027, Australia<br />
MILLIKEN T<br />
P O Box 30131<br />
Lilongwe 3<br />
Malawi<br />
MOLER P<br />
Florida Geme & Fish<br />
Commissioo<br />
4005 S. Main Str€et<br />
Gainesvillc<br />
FL 32601 USA<br />
MPIIANDE J<br />
P O Box 498<br />
Mzuzu, Malswi<br />
MUSOKOTWANE I<br />
IUCN<br />
P O Box 7.15<br />
Harare<br />
Zimbabwe
282<br />
NIGIITINGALE S<br />
P O Box 630825<br />
Choma, Zambia<br />
ONIONS Y<br />
P O Box 669<br />
Crims<br />
Queensland ,|t70<br />
Austnlia<br />
ORTIZ B<br />
Cslle 91-13A-45 apt 303<br />
Bogota<br />
Colo|Dbia<br />
South Americs<br />
PAT.ACIOS I<br />
Carrcra 35 No 1lX-65<br />
Ssnts Fe de Bogote<br />
Colombia<br />
South Anrerica<br />
PANI M<br />
TRAFFIC (Iaaly)<br />
via Selamis 290<br />
fi)199 Roms<br />
It8ly<br />
PASCAL D<br />
P O Box 130<br />
Norton<br />
Zimbabw€<br />
PENTOLFE N<br />
P O BOx 389<br />
Chiledzi<br />
Zimbabwe<br />
PENZHORN H<br />
201 Medical Cenare<br />
Jakantrdr Hospital<br />
MuckleDeur<br />
PrctoriN mO2<br />
Republic of South Africsn<br />
MTANAKORN P<br />
Crocoilile Ms trrgement<br />
Associstion of Thailand<br />
Faculty of Science<br />
Kasetssrt Uhive$ity<br />
P O Box 9-10900<br />
Bengkok 10900<br />
Thailand<br />
RAIIARJO Y<br />
P O Box 123<br />
Bogor 16001<br />
Indorcsia<br />
RANOT S<br />
32 Rewtzki Streea<br />
Rssnana, Isr|el<br />
RDVOL B<br />
P O Box HGll<br />
Highbnds Herare<br />
Zimbabwe<br />
RICE K<br />
2508 Southwesa 35 Plsce 55<br />
Gainsville<br />
Florida UsA<br />
ROSS J P<br />
CSG, Florido Muscum of<br />
Neturel History<br />
Gainesville<br />
FlJ2611<br />
USA<br />
RULE I<br />
P O Box 241<br />
Chirudzi<br />
Zimbabwe<br />
SCHOEMAN P<br />
POBoxl<br />
Malelane<br />
Republic of South Africl<br />
SEVERRE E<br />
Ministry of Tourism, Natural<br />
Resources & Envimnment<br />
Wildlife Divisio[<br />
P O Box 1994<br />
Dar-es-Saltem<br />
Tenzania<br />
SHIELD J<br />
P O Box 652<br />
Cairns ,18?0<br />
Australia<br />
SMITH G<br />
Posbus ,180<br />
ftcne 1675<br />
ftepublic of South Africa<br />
SOMMER H<br />
P O Box 1105<br />
Bulewayo<br />
Zimbsbwe<br />
STAMBULIE M<br />
F-d. Banco Popular # 1207<br />
Cartsgena<br />
Colombia<br />
Souah America<br />
STATON M A<br />
P O Box 30985<br />
Lafayette<br />
Louisians 70593 USA<br />
STEYN G<br />
89 Oosa Sl<br />
Piete$burg 0700<br />
Republic of South Africs<br />
SIJMMERS R<br />
P O Box HG 300<br />
Highlands<br />
Harare<br />
Zimbab\ve<br />
SWALES K W<br />
POBox33<br />
Darwendale<br />
Zimbabwe<br />
TAMARACK J<br />
Wildlife Survivol Center<br />
Rt. I Box 207-2<br />
Midway<br />
Ga 31320 USA<br />
TANGARWATCIIANAKARN<br />
Chamwit<br />
Spirachatarm Co Ltd<br />
POBox16<br />
Srimcha<br />
Cholburi 20110<br />
Thailand<br />
TAYLOR P<br />
P O Box 191<br />
Harsre, Zimbabwe<br />
TAYLOR R<br />
P O Box 8,137<br />
Causeway<br />
Harare<br />
Zirnbabwe
TEMSIRIPHONG M<br />
Sfirachatarm Co Ltd<br />
POBox16<br />
Sriracha<br />
Cholburi 20110<br />
Thailand<br />
THOMAS J<br />
P O Box 30131<br />
Lusaka<br />
Zambit<br />
TIFFIN J<br />
P O Box 8067<br />
Causeway<br />
Harare<br />
Zimb$bwe<br />
van der RIET R T<br />
P O Box 191<br />
Harare<br />
Zimbsbwe<br />
vsn der RIET M R<br />
P O Box 191<br />
Harare<br />
Zimbabw€<br />
vsn JAARSVELDT J<br />
POBox16<br />
Binga<br />
Zimbabwe<br />
vsn JAARSVELDT K<br />
414a Sabi Drive<br />
Chiredzi<br />
Zimbabwe<br />
VERDADE L M<br />
Cizbas / Esila / University of<br />
Seo Paulo<br />
Caixs Postal 09<br />
Piracicsbs 13400 SP<br />
Brazil<br />
\tsLASCO A<br />
Seraicio Autonomo Pmfavns<br />
Edp. Crmejo, Mezzsnina<br />
Oeste, CSB Cerecas l0l0<br />
Venezuela<br />
WEBB G<br />
P O Box 3E151<br />
Winnellie NT 0E2l<br />
AustnElie<br />
WILKIN D H<br />
Mairland Holdings<br />
P,O, Box 196 Lae<br />
Papu, N€e Guinea<br />
WILKINSON P<br />
407 M€eaing St<br />
G€orgetown<br />
SC 29,140<br />
USA<br />
WOODWARD A<br />
Wildlife Research Laboralory<br />
4005 Soulh Main Street<br />
Gainesville<br />
FL 32601-9099<br />
USA<br />
YOUNG R<br />
POBox5<br />
Sherwood<br />
Bolswane<br />
YOUNG E & R<br />
P O Box 522<br />
Thonotosrssa<br />
FL 33592<br />
USA<br />
YOUNGPRAPAKORN<br />
Chamon<br />
Samutprakarn <strong>Crocodile</strong><br />
Farm & Z,oo<br />
555 Taiban Rd<br />
Semutprakorn<br />
Thailand