INTRODUCTION 



In recent years there have been several notable strandings of bottlenose 

 dolphins (Tursiops truncatus) along the U.S. Coast Approximately 740 dolphins 

 were stranded along the East Coast in 1987-1988 and another 350 along the Gulf 

 Coast in 1990. One of the reports on the earlier dolphin strandings (Geraci 

 1989) suggests that environmental contaminants found in the dolphin tissues were 

 of possible health concem even though the direct cause of death was possibly due 

 to brevetoxin. After the 1990 stranding, there was renewed concem that 

 environmental pollutants might be instrumental in Ae in[q)aired health of these 

 animals. 



Elevated levels of chlorinated hydrocarbons (CHs) — including PCBs, 

 DDTs and other CHs (e.g. pesticides) — and certain metals have been reported in 

 a number of marine mammal species. For example, CHs and heavy metal 

 contaminants have been reported in white-beaked dolphins (Lagenorhynchus 

 albirostris) and pilot whales (Globicephala melaena) from Newfoundland, Canada 

 (Muir, et al. 1988), striped dolphins (Stenella coendeoalba) from Japan (Honda, 

 et al. 1983), short-finned pilot whales (Globicephala macrorhyncha) and long- 

 snouted dolphins (Stenella longirostris) from the Caribbean (Gaskin, et al. 1974), 

 and a bottlenose dolphin {Tursiops gephyreus), franciscana dolphins {Pontoporia 

 blainvillei) and a pigmy speim whale (Kogia breviceps) from the Southwest 

 Atlantic beaches in Argentina (Marcovecchio, et al. 1990). 



Although the literature on bottlenose dolphins is more limited than for 

 certain other marine manunal species, environmental contaminants have also been 

 identified in this species of dolphins by several research groups. O'Shea, et al. 

 (1980) reported high concentrations of PCBs (- 440 jig/g, wet weight) and DDTs 

 (~ 2200 fig/g, wet weight) in blubber of two bottlenose dolphins from California. 

 Similarly, the concentration of total PCBs in blubber of one bottlenose dolphin 

 calf from Cardigan Bay, England (Morris, et. al. 1989) was also elevated 

 (~ 290 ^g/g, wet weight). Two bottlenose dolphins sampled near the British Isles 

 had somewhat elevated concentrations of mercury (- 22 ^g/g, wet weight) in 

 liver (Law, er a/. 1991). In addition, Geraci (1989) reported the mean 

 concentration of PCBs in blubber of a subset of dolphins (n = 56) from the 1987- 



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