The timing and route of movement and migration of post-copulatory female blue crabs, Callinectes sapidus Rathbun, from the upper Chesapeake Bay

The movement of mature female blue crabs Callinectes sapidus Rathbun from lower salinity areas to spawn near the months of estuaries is well documented, but specific details of the post-copulatory phase of their migratory behavior are poorly understood in Chesapeake Bay. To test the hypotheses about the timing and route of this migration, we conducted a mark-recapture study of mature females released in a mesohaline portion of the upper Chesapeake Bay. From June 1999 to October 2002, 1440 mature female blue crabs were obtained from fishers, tagged, and released in the vicinity of the Rhode River, Maryland, approximately 200 km distant from the mouth of the Bay. As of the end of 2002, 167 crabs were recaptured (11.6%), with considerable variation in recapture rates among years. All recaptures except one (in Flagler Beach, Florida) were caught within the Chesapeake Bay proper. Recaptures of female crabs released at monthly intervals from June-November indicated that migration Occurred during a short fall period rather than over the prolonged period of summer to fall mating. The distances traveled by crabs before recapture differed significantly among release months. On average, crabs released in September and October traveled greater distances than crabs released in earlier months (June August). Depths of recapture sites differed significantly among months, with shallow depths in June-August increasing in September to a maximum in November. The locations and bathymetry of recapture sites showed that female crabs used areas near the deep channel, especially the eastern shoulder. of the Bay as a migration corridor to the spawning areas of the lower estuary. The distinct fall season and route of migration should provide valuable management information for protecting the declining spawning stock of Chesapeake blue crabs. Published by Elsevier B.V.