Chapter V — Marine Mammal Strandings and Die-offs 



Figure 14. Mass stranding of long-finned pilot whales on Cape Cod in 1990. Stranded marine 



mammals provide an important source of tissue samples for scientific research. 



(Photograph courtesy of Valerie Lounsbury) 



Biologists from the National Marine Mammal 

 Laboratory reported that similar impacts were seen 

 during the 1983 and 1992 El Nino events. In 1983 

 northern fur seal pup production on San Miguel Island 

 declined by 60 percent and first-year mortality was 

 close to 100 percent; pup production by California sea 

 lions in the Channel Islands also declined by about 30 

 to 70 percent, and northern elephant seal pup mortali- 

 ty due to storms was high (70 percent on Ano Nuevo 

 Island). In spite of the impacts of these events, U.S. 

 west coast populations of northern elephant seals, 

 northern fiir seals, harbor seals, and California sea 

 lions have increased dramatically since the 1970s. 



Beaked Whale Strandings in the 

 Southeastern United States 



Strandings of beaked whales of the genus Mesoplo- 

 don are normally rare in U.S. waters. Between late 

 August and mid-October 1998, twelve single strand- 

 ings (including one mother-calf pair) were reported in 

 the southeastern United States. The strandings 

 occurred on both the Atlantic and Gulf of Mexico 

 coasts. Investigations revealed no consistent patterns 

 suggestive of a single cause. Antibodies to morbilli- 

 virus were found in one individual; several whales 



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