
TY  - JOUR
A1  - Cailliet, GM 
T1  - Demography of the central california population of the Leopard Shark (<I>Triakis semifasciata</I>)
JF  - Marine and Freshwater Research
JO  - Mar. Freshwater Res.
Y1  - 1992
VL  - 43
IS  - 1
SP  - 183
EP  - 193
KW  - 
UR  - https://doi.org/10.1071/MF9920183 
N2  - Demographic analyses can be quite useful for effectively managing elasmobranch fisheries.  However, they require valid estimates of age-specific mortality and natality rates, in addition  to information on the distribution, abundance, habits and reproduction of the population, to  produce reliable estimates of population growth. Because such detailed ecological information  is usually unavailable, complete demographic analyses have been completed for only four shark  species: the spiny dogfish, Squalus acanthias; the soupfin shark, Galeorhinus australis; the lemon  shark, Negaprion brevirostris; and most recently the sandbar shark, Carcharhinus plumbeus.  In California, reliable estimates of age, growth, mortality, age at maturity, and fecundity are  available only for the leopard shark, Triakis semifasciata. A demographic analysis of this  species yielded a net reproductive rate (Ro) of 4.467, a generation time (G) of 22.35 years,  and an estimate of the instantaneous population growth coefficient (r) of 0.067. If the mean  fishing pressure over 10 years (F= 0.084) is included in the survivorship function, Ro and r  are reduced considerably, especially if leopard sharks first enter the fishery at early ages.  A size limit of 120 cm TL (estimated age 13 years), especially for female sharks, is tentatively  proposed for the leopard shark fishery. 
ER  -

