Size and sex composition of three carcharhiniform sharks landed by a coastal artisanal fleet from the northeastern coast of Brazil

Abstract

Sharks are among the marine organisms most impacted by intense fisheries, a worrying fact since they are key components in the trophic structure of ecosystems. In this context, fish landing data can help managers in shark conservation. This study characterized the landings of Carcharhinus acronotus, Mustelus cf. canis, and Sphyrna mokarran in the Mucuripe Embayment, Ceará, Brazil, along three study periods (1998–1999, 2006–2008, and 2015–2016). A total of 223 specimens were recorded from 227 site visits. Carcharhinus acronotus specimens measured from 50 to 139 cm in total length (TL), with a 1.3:1 sex ratio in favor of males. Most of the specimens recorded were adults (55.1% of males and 62.9% of females). Mustelus cf. canis varied from 64 to 133 cm in TL, with a sex ratio in favor of females (3.1:1). Most of the specimens recorded were adults (50% of males and 68% of females). Sphyrna mokarran specimens varied from 116 to 380 cm in TL, with a sex ratio of 7:1 in favor of males. Most of the specimens recorded were juveniles. This is the first fishery-dependent study to provide information on size and sex composition of these species for most of the southwestern equatorial Atlantic.