Distribution, Relative Abundance, and Reproductive Output of Spawning Female Blue Crab (\u3ci\u3eCallinectes sapidus\u3c/i\u3e) In Offshore Waters of the Gulf of Mexico

Effective assessment and management of migratory species require an understanding of stock boundaries and habitat use during critical life history periods. The blue crab (Callinectes sapidus) is considered a primarily estuarine species and has traditionally been assessed and man-aged on a state basis, relying on abundance estimates derived from estuarine sampling. Females undertake a sea-ward spawning migration, and recent evidence indicates that coastal and offshore waters may provide important spawning habitat. We investigated occurrence and reproductive output of spawning blue crab in offshore waters of the northwestern Gulf of Mexico, and results indicate that these waters may be an important spawning area for this species. Densities of blue crab were low offshore compared with those in estuaries, but given the large extent of available offshore habitat, the total abundance of adult females is likely similar in offshore and estuarine waters. Analyses of the reproductive output of females collected offshore indicate that they continue to spawn after leaving the estuaries. Fecundity and measures of egg quality were assessed and were similar to previous estimates for estuarine regions. Future management and assessment efforts should account for this previously understudied portion of the blue crab spawning stock