Kyne & Simpfendorfer.. - Shark Specialist Group

Table 2.8. Age and growth of somniosid sharks. von Bertalanffy growth model (VBGM)
parameters: L ∞ (mm TL), k (year -1 ), t 0 (years); t max oldest fish (years), A mat age at maturity
(years). Band count method: Int DS, internal dorsal spine band count; Ext DS, external dorsal
spine band count; RadioM, radiometric ageing.
Species Location Method
VBGM parameters
L ∞ k t 0
t max A mat Reference
Centroselachus
crepidater
SE Australia Ext DS ♀ 961
♂ 732
0.072
0.141
-6.13
-2.99
54
34
20
~9
Irvine et al. (2006b)
SE Australia Int DS ♀ 932
♂ 706
0.163
0.362
-1.92
-1.51
27
22
--
--
Irvine (2004)
SE Australia RadioM ♀+♂ -- -- 43 -- Fenton (2001)
Proscymnodon
plunketi
SE Australia Ext DS ♀ --
♂ --
--
--
--
--
39
32
29
18
Irvine (2004)
Family Oxynotidae. Roughsharks.
The roughsharks are a poorly-known group of deepwater dogfishes. There is some basic
published data on the angular roughshark Oxynotus centrina from the Mediterranean and
eastern Atlantic, but little information available on the other four species. Oxynotus centrina
has been reported with litters of 10-15 with a reproductive cycle that is suggested to last
around one year (Capapè et al. 1999, Megalofonou and Damalas 2004). Maturity occurs at
650mm TL and 600mm TL for females and males, respectively, which corresponds to 83%
and 94% of TL max in the study (Capapè et al. 1999). Size at birth is suggested to be 210–
240mm TL (Capapè et al. 1999).
Last and Stevens (1994) reports a litter size of seven from a single female O. bruniensis,
endemic to the Australasian region. There is no information available on the biology of O.
caribbeaus, O. japonicus or O. paradoxus.
Family Dalatiidae. Kitefin Sharks.
Biological information on the largely pelagic kitefin sharks is limited, and the nine deepwater
species are generally very poorly-known. A few species, such as the taillight shark
Euprotomicroides zantedeschia, longnose pygmy shark Heteroscymnoides marleyi, the South
China cookiecutter shark Isistius labialis and the pocket shark Mollisquama parini are known
only from a handful of specimens (I. labialis and M. parini are each known only from single
specimens).
The kitefin shark Dalatias licha reaches at least 1590mm TL and possibly over 1800mm TL
(Compagno in prep. a). Preliminary maturity estimates suggest that males from southern
Australia mature at 1090–1130mm TL (Daley et al. 2002) and females mature at ~1200mm
TL (Last and Stevens 1994). Other members of this family are very small, including the
world's smallest shark, the smalleye pygmy shark Squaliolus aliae, which reaches a maximum
size of 220mm TL (Last and Stevens 1994). Some species such as Isistius and Squaliolus are
vertical migrators, moving up the water column at night and returning to deeper water during
the day. Litter sizes in the family, like most other squaloid species are small. For D. licha
Compagno (in prep. a) reported 10–16 and in four gravid females Daley et al. (2002)
observed litter sizes of 7–11. A litter size of nine has been reported for Isistius brasiliensis
(Gadig and Gomes 2002) and four has been reported in Squaliolus laticaudus (Cunha and
79