Abstract

A mark-recapture method was used to make sex-related estimates of the selectivity of the fishing gear, abundance and density of the Atlantic blue crab (Callinectes sapidus) on the northern coast of the Yucatan Peninsula, using both the Jolly-Seber model and the density by catchability (CPUE * q), both derived from data obtained from a period of six consecutive fishing days. For this purpose, 52 traps were used, divided into four transects placed parallel to the coastline. The traps were placed at dusk and checked at dawn, standardizing the fishing effort in 17 hours trap-1 day-1. A total of 614 crabs were captured, of which 594 did not register marks and 20 were recaptured with mark. The sex ratio male: female through-out the capture was 1:3.78. In relation to size (carapace width, CW), a different sex ratio was also observed for almost all size classes. The selectivity of the fishing gear or first catch size (L50) was estimated at 142.3 and 153.3 mm CW, for fe-males and males, respectively. The catch per unit of effort (CPUE) was estimated in 0.15 (males) and 1.92 (females)/trap organisms. According to the Jolly-Seber model, the average abundance of males was 347 organisms and 2912 for females, resulting in a population of 3,259 crabs. Based on these estimations of abundance by sex, it was observed that the density for males was 0.0039 crabs/m2 (39 males per hectare) and for females of 0.0323 crabs/m2 (323 females per hectare). Mean-while, based on to the catchability density (CPUE * q), similar densities of 0.0340 males/m2 and 0.0243 females/m2 were observed.

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