Bottlenose dolphins and the Atlantic blue crab fishery: A study of coincidence and interaction in Charleston Harbor, SC

The Atlantic blue crab fishery has been implicated in a significant number of entanglements, and the gear used is known to have caused injury and death to bottlenose dolphins (Tursiops truncatus) throughout the southeastern United States. In order to study this fishery interaction, boat-based surveys were carried out in Charleston Harbor, SC from April through October 2008. Observations were conducted for 313h over 3604.8km along a standard transect. During these surveys 2696 dolphins were counted through 646 sightings, 9425 buoys were observed and mapped, and dolphins were observed within 5m of 104 buoys. It was found that dolphins are sighted in the vicinity of Atlantic blue crab fishery gear more often than expected at random. Dolphins were observed engaged in behaviors hypothesized to increase the risk of entanglement. Specific individual dolphins are more likely to be sighted in the vicinity of gear, however no specific age or sex predominated. Interviews of local crab fishers were conducted to collect data regarding dolphin behaviors around gear and boats to assess the impact of dolphins on pots and catch. Results of this study will be used to formulate recommendations for managing dolphin interactions with the Atlantic blue crab fishery.