Abundance and catchability estimates of the Atlantic blue crab Callinectes sapidus based on mark-recapture data from the northern Yucatan Peninsula

Abstract

A short-term Jolly–Seber mark-recapture model experiment is described. This experiment was aimed at estimating the rate ofcatch per unit effort (CPUE) and the catchability coefficient (q) of the Atlantic blue crab (Callinectes sapidus) in the fishingport of Sisal, Yucatan, Mexico. To estimate the local population size, 52 traps were deployed along four transects located in acoastal capture area of 3600 m22. The CPUE and q were compared between the daily mark-recapture Jolly –Seber experimentand the bi-monthly (carried out every 2 months) samplings. The average abundance was estimated at 3475 individuals. Allthree suggested scenarios, applied to estimate densities, gave similar estimates, i.e. 0.0386, 0.0350, 0.0365 crabs m22for thefirst (Previously Cited Attraction Radius), second (CPUE per transect) and third (Catchability-Density Relationship), respect-ively. Based on the latter scenario, densities ranged from 27,900 (annual average) to 36,500 (Spring) crabs km22. The averageCPUE of the daily mark-recapture experiment was estimated at 1.96 crabs trap21, whereas the average bi-monthly CPUE wasestimated at 1.13 crabs trap21. The q (per trap) was estimated at 0.0186 for the daily mark-recapture experiment and at0.0247 for the bi-monthly sampling. Both catchability and CPUE increased in individuals whose size ranged between 110and 170 mm CW. However, no significant difference (ANCOVAs) was found between the daily and bi-monthly samplingsneither in CPUE nor in catchability. The use of both mark-recapture data and the Jolly–Seber model proved to be a fastand reliable method for estimating the abundance and catchability of Atlantic blue crab.