Kyne & Simpfendorfer.. - Shark Specialist Group

More documents

Recommendations

Info

16 embryos (Table 2.5). Irvine (2004) found strong correlations between maternal size and the number of follicles and the number of embryos and within the New Zealand lanternshark E. baxteri from southern Australia and Yano (1995) found similar results for the black dogfish C. fabricii from Greenland. Etmopterids do not appear to have well-defined reproductive seasons, and have a noncontinuous reproductive cycle with an apparent resting stage after parturition. This is supported by observations that follicles do not continue to develop throughout gestation (i.e. gravid females do not possess developing or mature oocytes) and the finding of numerous large females with inactive reproductive tracts (Yano 1995, Daley et al. 2002, Irvine 2004). With species exhibiting aseasonal reproductive cycles, the duration of any resting stage after parturition and prior to next ovulation is difficult to assess as each reproductive stage occur can be found in any month sampled (Irvine 2004). Furthermore, gestation period has not been calculated. Age estimates are available for only two species of lanternshark, and these are unvalidated and thus should be considered as preliminary (Gennari et al. 2002, Sion et al. 2002, Irvine et al. 2006a). Irvine et al. (2006a) estimated age from both internal and external bands on the second dorsal spine of E. baxteri. While there were considerable differences in age estimations between these techniques (see Table 2.6), Irvine et al. (2006b), in an aging study of the somniosid Centroselachus crepidater, suggested that internal bands may underestimate age. Similarly, for E. baxteri, internal bands become unreadable as internal dentine appears to stop forming in adult fish (Irvine et al. 2006a). As such, count estimates from external bands are more reliable, and for E. baxteri this technique gives a maximum age of 57 years for females and 48 years for males, with age at 50% maturity of 30 years for females and 20 years for males (Irvine et al. 2006a). Vertebral band counts for the velvet belly E. spinax from the Mediterranean present 7 bands for the largest individuals (Gennari et al. 2002, Sion et al. 2002). There is a considerable size difference between E. spinax which rarely reaches >450mm TL (although can reach 600mm TL) and E. baxteri with reaches 880mm TL (Compagno et al. 2005). Irvine (2004) calculated lifetime fecundity for E. baxteri, utilising a mean litter size of 6-12 (variable with maternal size) and the number of reproductive years as 27, and applying either a two or three year reproductive cycle. If the species reproduces biennially, Irvine (2004) calculated that the lifetime fecundity of a female E. baxteri is 128 pups, and if it reproduces triennially, then the lifetime fecundity would be 81 pups. 74
Table 2.5. Reproductive biology of etmopterid sharks. A litter size value in parentheses is the mean value. Where uterine litter size is not available ovarian fecundity may be given (ovarian). Species Location TL max (mm) Maturity (mm TL) Maturity %TL max Litter size Size at birth (mm TL) Reference Centroscyllium fabricii Greenland, NE Atlantic ♀ 898 ♂ 760 ~650 ~550 72 72 4-40 (16.4) 165-192 Yano (1995) Iceland, NE Atlantic ♀ 1060 ♂ -- 703 (L 50 ) 573 (L 50 ) 66 -- -- -- Jabobsdóttir (2001) Centroscyllium kamoharai SE Australia ♀ 630 ♂ 540 ~550 ~440 87 81 3-22 (12) -- Daley et al. (2002) Etmopterus baxteri New Zealand, SW Pacific ♀ 788 ♂ 697 640-690 550-580 81-88 79-83 9-15 (12.7)
Page 1 and 2:
A COLLATION AND SUMMARIZATION OF AV
Page 3 and 4:
TABLE OF CONTENTS Executive Summary
Page 5 and 6:
Reproductive output in deepwater ch
Page 7 and 8:
GENERAL INTRODUCTION THE CLASS CHON
Page 9 and 10:
Leucoraja circularis, blonde skate
Page 11 and 12:
SECTION I. BIODIVERSITY AND AN ANNO
Page 13 and 14:
Table 1.1. The diversity of deepwat
Page 15 and 16:
ANNOTATED CHECKLIST OF EXTANT DEEPW
Page 17 and 18:
Habitat zones broadly follow Compag
Page 19 and 20:
Chimaera lignaria Didier, 2002. Gia
Page 21 and 22:
Hydrolagus trolli Didier & Séret,
Page 23 and 24: Squalus melanurus Fourmanoir, 1979.
Page 25 and 26: Deania hystricosum (Garman, 1906).
Page 27 and 28: Etmopterus molleri (Whitley, 1939).
Page 29 and 30: Scymnodalatias sherwoodi (Archey, 1
Page 31 and 32: Squatina formosa Shen & Ting, 1972.
Page 33 and 34: Torpedo nobiliana Bonaparte, 1835.
Page 35 and 36: Bathyraja matsubarai (Ishiyama, 195
Page 37 and 38: Brochiraja spinifera (Garrick & Pau
Page 39 and 40: Amblyraja hyperborea (Collette, 187
Page 41 and 42: Dipturus mennii Gomes & Paragó, 20
Page 43 and 44: Fenestraja cubensis (Bigelow & Schr
Page 45 and 46: Okamejei sp. N [Last & Stevens, 199
Page 47 and 48: Family Anacanthobatidae. Legskates.
Page 49 and 50: Family Dasyatidae. Whiptail Stingra
Page 51 and 52: Apristurus kampae Taylor, 1972. Lon
Page 53 and 54: Apristurus sp. [Séret]. Western Ce
Page 55 and 56: Western Central Atlantic: Straits o
Page 57 and 58: Pentanchus profundicolus Smith & Ra
Page 59 and 60: Mustelus canis insularis (Mitchell,
Page 61: Musick, J.A., Harbin, M.M. and Comp
Page 64 and 65: efore relying on ovulated ova) and
Page 66 and 67: FAMILY LIFE HISTORY ACCOUNTS PART 1
Page 68 and 69: Family Squalidae. Dogfish Sharks. T
Page 70 and 71: often related to maternal size, lar
Page 72 and 73: Table 2.3. Reproductive biology of
Page 76 and 77: Table 2.6. Age and growth of etmopt
Page 78 and 79: Table 2.7. Reproductive biology of
Page 80 and 81: Gonzalez 2006). Daley et al. (2002)
Page 82 and 83: and in the case of the crocodile sh
Page 84 and 85: Balart et al. (2000) is 295mm TL fo
Page 86 and 87: Table 2.11 (continued). Species Loc
Page 88 and 89: PART 2. BATOIDS Order Rajiformes. B
Page 90 and 91: years for females of all species ag
Page 92 and 93: Ebert and Davis 2007). These are th
Page 94 and 95: Table 2.15. Age and growth of rajid
Page 96 and 97: PART 3. HOLOCEPHALANS Order Chimaer
Page 98 and 99: SEGREGATION, MOVEMENT AND MIGRATION
Page 100 and 101: PRODUCTIVITY OF DEEPWATER CHONDRICH
Page 102 and 103: e slow to recover from overfishing.
Page 104 and 105: 0.16 0.14 Intrinsic rebound potenti
Page 106 and 107: Bigelow, H.B. and Schroeder, W.C. 1
Page 108 and 109: Conrath, C.L., Gelsleichter, J. and
Page 110 and 111: Squaliformes) in the southwestern e
Page 112 and 113: Hoenig, J.M. 1983. Empirical use of
Page 114 and 115: Lucifora, L.O., Valero, J.L. and Ga
Page 116 and 117: Parsons, G.R., Ingram, G.W. Jr. and
Page 118 and 119: Sulikowski, J.A., Elzey, S., Kneebo
Page 120 and 121: K. (eds.). Indo-Pacific Fish Biolog
Page 122 and 123: deepwater species categories for ea
Page 124 and 125:
Table 3.1. FAO FIGIS database categ
Page 126 and 127:
CASE STUDY 1. AUSTRALIAN SOUTHERN A
Page 128 and 129:
Table 3.2. Mid-slope deepwater shar
Page 130 and 131:
CASE STUDY 2. NORTHEAST ATLANTIC DE
Page 132 and 133:
CASE STUDY 3. AZORES KITEFIN SHARK
Page 134 and 135:
CASE STUDY 4. MALDIVES GULPER SHARK
Page 136 and 137:
SECTION III LITERATURE Adam, M.S.,
show all

Kyne & Simpfendorfer.. - Shark Specialist Group

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?