Biometric characterization of sharks of the genus Sphyrna (Griffith & Smith, 1834) on the coast of Sergipe

Abstract

Sharks, rays and chimeras belonging to the subclass  Elasmobranchii of the class Chondrichthyes have a slow maturation and development, and they are animals often caught as by-catch, making them vulnerable to extinction. Six species of the genus Sphyrna are found in Brazil, in the coastal-oceanic zone, three of which were studied: Sphyrna lewini, S. mokarran and S. tiburo. This study aimed to evaluate the biometrics, sex and stage of sexual development of the genus Sphyrna in artisanal fishing in Aracaju (SE). The animals used included specimens from the GEES collection and fresh ones acquired from local fisheries. S. tiburo was found only in the collection. The species S. mokarran and S. lewini included more newborn individuals and males and S. tiburo more females and juveniles. In fresh species, pectoral-pelvic length was greater in females, and pelvic-anal length was greater in males of S. lewini. Weight was greatest in S. lewini, while there was no difference in total length, head width and interdorsal length between specimens. The parameters measured did not show significant results that could be related to by-catch with many immature individuals.