Population structure and reproductive aspects of Callinectes ornatus (Decapoda: Brachyura) present in the bycatch of shrimp fisheries in northeastern Brazil

This study aimed at analysing the population structure and reproductive aspects of Callinectes ornatus present in the bycatch of shrimp fisheries off Sergipe (northeastern Brazil), and at comparing the findings with other regions. Samples were obtained monthly from shrimp trawlers based in the Pirambu municipality (11°S–37°W) from May/2015 to May/2016. Each specimen of C. ornatus was separated, identified and weighed (TW, total weight, g). Carapace length (CL, mm) and width (CW, not including lateral spines, mm) were measured, and the sex and stage of morphological maturity were identified. A total of 403 females and 427 males of C. ornatus were found and analysed. The overall sex ratio did not differ from 1:1. Males were larger and heavier than females. Biometric relations (CL‐CW and TW‐CW) were different between sexes. The size at first morphological maturity (CWm) was 38.20 mm for females and 44.00 mm for males. The reproductive and recruitment periods were continuous, with some peaks throughout the year. Despite C. ornatus being a frequent species in shrimp bycatch, its exploitation status is still unknown.