The size at maturity of the brown crab Callinectes bellicosus (Decapoda, Portunidae) in the Gulf of California

This study describes the size (carapace width, CW) at maturity of Callinectes bellicosus (Stimpson, 1859) based on samples from a coastal lagoon in the southern Gulf of California. The study was conducted since knowledge of the species in particular and the genus in general on the Pacific coast is scarce or non-existent and size at maturity is a key biological parameter for fisheries management. The collection of statistics on the crab fishery began in 1982, but landings of crab from the fishery increased exponentially until 2003. Samples were collected at the mouth of the lagoon and in the inside lagoon. A total of 651 brown crabs, including 255 females and 396 males, were processed from both sites. The crabs from the coastal lagoon showed a marked segregation of the sexes. In all, 73% of the crabs from the inside lagoon were males, and 71% of the crabs from the mouth of the lagoon were females. Immature females were predominant (78% of all females) in the inside lagoon, whereas mature females were predominant (81% of all females) at the mouth of the lagoon. Segregation according to the size at maturity was observed. The size at maturity was greater in the inside lagoon (114.08 mm CW) than at the mouth of the lagoon (103.73 mm CW). The pooled size at maturity was 107.78 mm CW. This report presents the first information on segregation by sex and maturity stage in any Callinectes species from the Mexican Pacific coast. These findings are important not only for fisheries management but also for the general biological knowledge of Callinectes species. We concluded that this study offers an improved approach for evaluating fisheries management, at least for the species studied here.