Abstract

NAVA NAVA, Prisma  and  MARQUEZ-FARIAS, Juan Fernando. Size at maturity of the smooth hammerhead shark, Sphyrna zygaena, captured in the Gulf of California. Hidrobiológica [online]. 2014, vol.24, n.2, pp.129-135. ISSN 0188-8897.

Size at first maturity was determined for females and males of smooth hammerhead shark, Sphyrna zygaena captured in the Gulf of California during 1995-2000. A total of 1,041 organisms (461 females and 580 males) were analyzed. The size of females ranged 46.0-286.3 cm of total length (TL) whereas the size of males ranged 49.5-278.0 cm TL. The most recurrent captured size for both sexes was 175.0-185.0 cm TL. Immature organisms were the main component of the catches for both sexes. Sex ratio (females:males) for neonates, juveniles and adults was 0.96:1, 0.74:1 and 1.17:1, respectively. Based on the weight-length relationship, it was observed that females are larger and heavier than males with positive allometric growth for both sexes. The logistic model showed that 50% of females are mature at 200.0 cm TL, whereas 50% of males are mature at 193.7 cm TL. The results of this study provide useful information to propose measures S. zygaena management since it is a species that requires attention due to their biological and commercial importance.

Keywords : Elasmobranchs; proportion of maturity; reproductive biology; Sphyrna zygaena.

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