Background:

Sphyrna lewini is a semi-oceanic and cosmopolitan species globally distributed throughout tropical and warm temperate seas. In the northeastern tropical Pacific, this species is an important contributor to the biomass of artisanal fisheries.

Goals:

The aim of this study was to examine the length frequency distribution and reproductive aspects of S. lewini in Oaxaca, Mexico.

Methods:

Samples were taken from August 2001 to December 2007 in four landing sites of the artisanal fleet on the coast of Oaxaca.

Results:

The samples included 388 females and 434 males. Total length ranged from 44 to 332 cm for females and from 44 to 308 cm for males. The catches were made up of neonates (24.3%, 44-74 cm), juveniles (42.2%, 75-170 cm), and adults (33.5%, > 170 cm). The most abundant catches were recorded in the rainy season (85.5%), with a predominance of juveniles and adults, and a higher proportion of males. The remaining 15.5% of catches, recorded in the dry season, had a predominance of larger sizes (>100 cm) in both sexes. The females reached sexual maturity (TL50) at 199 cm and the males at 181 cm. 37 gravid females with sizes between 175 and 281 cm were registered from April to August. Gravid females had between 15-42 embryos, varying from 44-54 cm.

Conclusion:

The results of this study identify the coast of Oaxaca as an important area for the reproduction of S. lewini on the southern Pacific coast of Mexico, providing information for management and conservation of this species.