Distribution patterns of the warrior swimming crab, Callinectes bellicosus, fishery in Bahía Magdalena, Baja California Sur, Mexico

Abstract

Abstract Spatial and temporal distribution patterns of the warrior swimming crab Callinectes bellicosus fishery in the Mexican Pacific were investigated. Geo-referenced commercial trap capture data derived from 44 trips in the Bahia Magdalena were analysed. Three fishing zones (Z1, inner; Z2, middle; Z3, mouth of the bay) and two climate seasons (warm, July-December; and cold, January-June) were defined previously. There were 1099 traps in Z1, 715 in Z2 and 2111 in Z3; in the warm season, 2091 traps were checked, whereas 1834 were checked in the cold season. The average number of individuals per trap (CPUE) varied by sex, zone and season, however, male crabs always predominated. During the warm season, large males (CW > 115 mm) exhibited the greatest value of CPUE. On average, the males represented 77% during the warm season and 84% during the cold season. The average size of the males (125 ± 0.843 mm CW) was significantly higher than the average size of females (121 ± 1.140 mm CW). The catch was composed of large mature males but females were absent in Z1; in comparison, both large mature males and females, in addition to ovigerous females, composed the catch at the mouth of the bay (Z3). Crab abundance was notably reduced in the cold season, especially for female crabs. The temporal behaviour of the warrior swimming crab in Bahia Magdalena is similar to that reported from the coastal lagoons of the Gulf of California; however, the low presence of females throughout the year could be related to their preferred environmental conditions, which include deeper areas with more current circulation, like those that occur at the mouth of the bay. These data corroborate the necessity to interpret with caution the crab population dynamics solely based on results derived from fishing with traps in coastal lagoons.