WOLCOTT, DL*; WOLCOTT, TG; HINES, AH; MEDICI, DA; NC State Univ.; NC State Univ.; Smithsonian Env. Res. Ctr.; Gulf & S. Atl. Fisheries Foundation: Migration of female blue crabs from mating areas to spawning grounds.

To elucidate how adult female blue crabs migrate from oligo- and mesohaline areas in which they mature and mate, to the euhaline areas where they begin producing broods, we have been fitting them with both simple ID tags and electronic dataloggers over several years in both Chesapeake Bay and North Carolina waters. The overall pattern, revealed by conventional mark-recapture techniques, is that females generally do not migrate promptly after mating. Most from upper Chesapeake Bay and the tributaries of Pamlico Sound (NC) remain near where they mated for the remainder of the summer, departing in Sept./Oct. and migrating seaward over the next several months. In the Chesapeake they often are recaptured along the deeper channels. Electronic CTD dataloggers, deployed (and recovered) in much smaller numbers, show that Chesapeake crabs often descend into the deepest channels of the Bay but may also travel in the shallows of the submerged floodplain. Patterns are variable; several females from the lower Bay (York River), and a few from the upper Bay, have not shown such dramatic movements out into the spawning grounds where we expected recaptures by the winter dredge fishery. After overwintering (> 6 months), they were recaptured within a few hundred meters of their release sites. Females in Pamlico Sound are so mobile (at least in dry years) that the NC �spawning sanctuaries� appear to be ineffectual. The probability of females being caught by the fishery is similar whether they are tagged on the western shore of the sound or in a sanctuary at an Outer Banks inlet to the sea. Conservation measures evidently must be site-specific. Supported by NOAA.