Winter Distribution of Sea Turtles in the Vicinity of Cape Hatteras and Their Interactions with the Summer Flounder Trawl Fishery
Aerial surveys of North Carolina offshore waters between Cape Lookout and the North Carolina/Virginia state line were conducted November 1991–March 1992 to determine the abundance of sea turtles in the area where a trawl fishery for summer flounder was active, and to relate the distribution of turtles to physical oceanographic processes. Turtles were sighted throughout the winter as far north as Oregon Inlet. Individual surveys yielded surface density estimates greater than l2 turtles˙100 km-2, depending on the method of analysis. The distribution of turtles appeared to be related to water temperature, with turtles being mostly in waters ≥11°C. Favorable temperature and depth regimes for sea turtles occur throughout the winter along the western edge of the Gulf Stream from the vicinity of Cape Hatteras southward. The nearshore waters of Raleigh Bay, more than any other nearshore area of the South Atlantic Bight, are affected in the winter by the warm, fast-moving Gulf Stream and its frontal eddies that impinge upon and override the narrow continental shelf. Characteristically the waters in the vicinity of Cape Hatteras are warmer in the winter than nearshore areas to the south. The narrowness of the continental shelf and the influence of the Gulf Stream on these nearshore regions serve to concentrate sea turtles emigrating from nearshore waters in the Middle Atlantic Bight and Pamlico and Core Sounds in the late fall and early winter. Thus, sea turtles can be at greater risk for interaction with fishing activity on the continental shelf near Cape Hatteras, during the winter, than in any other area in the South Atlantic Bight. The summer flounder fishery, operating between Cape May, New Jersey and Cape Lookout, North Carolina during November 1991–February 1992, was monitored for interactions with sea turtles. Observers were aboard nearly 6% of the reported trips landed in Virginia and North Carolina. The sea turtle catch comprised loggerheads (60%), Kemp's ridleys (36%), greens (2%), and a hawksbill (1%). The catch of Kemp's ridleys during November–December 1991 south of Cape Hatteras was high (N = 26). Overall turtle catch rates were similar to those reported for the Atlantic shrimp fishery, but catch rates south of Cape Hatteras were 6–8 times higher than catch rates north of the Cape. A total of 1,063 turtles was estimated to have been caught November 1991–February 1992, and 89–181 were estimated to have died as a result of the trawl fishery. None of the turtles tagged during this study was recaptured during the study period, but three were recaptured subsequently; one had been resuscitated. Trawl activity was aggregated, and a number of turtles required resuscitation after 60 min tows. Sea turtle conservation regulations are needed for this fishery because the turtle/fishery interaction is great (>1,000 turtles estimated caught), the proportion caught that is Kemp's ridleys is high (35%), and the physical processes that concentrate the sea turtles on the fishing grounds are operable every winter.
No Supplementary Data.
Document Type: Research Article
Publication date: 1995-03-01
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