CHAPTER III 



DIE-OFF OF BOTTLENOSE DOLPHINS (TURSIOPS TRUNCATUS) 



The bottlenose dolphin is the cetacean species most com- 

 monly seen in the coastal waters of the eastern United States. 

 Data compiled by the Smithsonian Institution indicate that, in 

 an average year, about 12 dead bottlenose dolphins will be found 

 washed up on beaches from New Jersey to Cape Hatteras. In 

 June 1987, unprecedented numbers of animals began to wash up 

 on New Jersey beaches. By the end of October 1987, at least 

 370 dolphins had washed ashore in New Jersey, Delaware, Mary- 

 land, and Virginia. By the end of the year, more than 100 

 additional animals had washed up on beaches in North Carolina, 

 South Carolina, Georgia, and northern Florida. 



The Marine Mammal Commission was advised of the die-off 

 in late July 1987 when unusually high numbers of bottlenose 

 dolphins began washing up on beaches in Virginia. The Commis- 

 sion immediately consulted the National Marine Fisheries Service 

 and a number of persons expert in bottlenose dolphin biology 

 and disease. The Commission asked Joseph R. Geraci, V.M.D., 

 Ph.D., a member of its Committee of Scientific Advisors and a 

 person expert in marine mammal husbandry and disease, to organ- 

 ize and lead an investigation to try to determine the cause 

 or causes of the die-off. 



To help in the investigation, the Commission asked the 

 Department of Agriculture's Animal and Plant Health Inspection 

 Service to conduct the range of bacterial and viral isolation 

 studies and other analyses necessary to determine whether 

 pathogenic organisms, environmental contaminants, or biological 

 toxins were causing or possibly contributing to the die-off. 

 The Commission also made arrangements with the Smithsonian 

 Institution to continue collecting basic data from the stranded 

 animals and with the U.S. Navy to provide facilities at the 

 Little Creek Amphibious Base for detailed postmortem exami- 

 nations of dolphins recovered in the Virginia Beach area. In 

 consultation with the National Marine Fisheries Service, the 

 Commission arranged for the Service's laboratory in Charleston, 

 South Carolina, to perform toxicological analyses. In addi- 

 tion, the Commission sought the assistance of the Environmental 

 Protection Agency in obtaining information on offshore dump 

 sites, possible illegal dumping, phytoplankton blooms, water 

 movement patterns, and other environmental factors that might 

 provide a clue to the cause of the die-off. 



The response team, with funding and administrative support 

 provided by the National Marine Fisheries Service, began its 

 investigations in the Virginia Beach area early in August. 



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