Fisheries Service conduct a study to examine: (1) the cause or 

 causes of the epidemic; (2) the effect of the epidemic on coastal 

 and offshore populations of Atlantic bottlenose dolphin; (3) the 

 extent to which pollution may have contributed to the epidemic; 



(4) whether other species and populations of marine mammals were 

 affected by those factors which contributed to the epidemic; and 



(5) any other matters pertaining to the causes and effects of the 

 epidemic. No funds were appropriated to the Service for this 

 study . 



The amendments required that the Service submit a plan for 

 conducting the study to the Senate Committee on Commerce, 

 Science, and Transportation and the House Committee on Merchant 

 Marine and Fisheries by 1 January 1989. However, because the 

 final report of the die-off investigation was not expected to be 

 completed until the end of January 1989, the Commission, by 

 letter of 6 December 1988, suggested that the Service advise the 

 concerned Congressional Committees of this fact when submitting 

 its required study plan. The Commission also pointed out that, 

 while the forthcoming report was expected to identify the likely 

 cause of the die-off, it would not provide an assessment of the 

 impact of the die-off on the affected population or populations 

 or indicate the follow-up studies that would be necessary to 

 determine how soon the population (s) may recover. The Commission 

 therefore suggested that the Service include in its research plan 

 a study to evaluate the impact of the die-off on the affected 

 populations and the recovery of the populations over time. 



A final report on the bottlenose die-off, "Clinical 

 Investigation of the 1987-88 Mass Mortality of Bottlenose 

 Dolphins along the U.S. Central and South Atlantic Coast," was 

 submitted to the National Marine Fisheries Service, the Office of 

 Naval Research, and the Marine Mammal Commission in April 1989. 

 The report concluded that the proximate cause of the die-off was 

 brevetoxin, a neurotoxin produced by the dinoflagellate 

 Ptychodiscus brevis . which causes "red tide." The brevetoxin 

 purportedly made the animals susceptible to a host of bacterial 

 and viral pathogens which ultimately killed them. The report 

 noted that high levels of contaminants (e.g. , organochlorines) 

 found in some but not all dolphins also may have made them more 

 susceptible either to the toxin or to the microorganisms that 

 eventually killed them. 



By letter of 15 December, the National Marine Fisheries 

 Service reported to Congress on its study of the die-off, 

 addressing the five points specified in the 1988 amendments to 

 the Marine Mammal Protection Act. The Service identified 

 brevetoxin poisoning, complicated by viral and bacterial 

 infections, as the probable cause of the mortalities. The 

 Service noted that, although such a conclusion is a reasonable 

 hypothesis based upon the Response Team's data, the cause (s) of 

 the epidemic had yet to be established conclusively. 



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