MARINE MAMMAL COMMISSION — Annual Report for 1995 



Bottlenose Dolphins 



During the first 19 days of December 1995, 17 

 bottlenose dolphins stranded along the coast of Texas. 

 Most of the dead dolphins were found on the seaward- 

 facing beaches of barrier islands and were badly 

 decomposed. The animals may have died in offshore 

 areas from multiple, unrelated causes and been carried 

 ashore by unusual tides, winds, or currents. The high 

 number of strandings did not continue after 19 De- 

 cember. 



Morbillivirus 



Since 1993 the National Marine Fisheries Service 

 has provided funds to the Alaska Department of Fish 

 and Game to assess the status and try to determine the 

 cause of declines in harbor seal populations in parts of 

 Alaska (see the harbor seal discussion in Chapter III 

 for information concerning the declines). The study 

 has included collection and testing of serum samples 

 for antibodies to several viruses, including the phocine 

 and canine distemper viruses. The tests were more 

 sensitive than those used previously and, although 17 

 of 42 samples tested positive for phocine distemper 

 antibodies and 2 of 42 samples tested positive for 

 canine distemper antibodies, the results may have 

 been false positives not indicative of infections. The 

 test results could indicate that harbor seals and possi- 

 bly other seals in Alaska have been exposed to the 

 type of virus that caused the deaths of more than 

 17,000 harbor seals in the North Sea in 1988. To 

 date, however, there have been no indications of 

 unusually high numbers of dead harbor seals or other 

 seals in Alaska or elsewhere along the Pacific coast of 

 North America. 



Two common dolphins that stranded live on 

 California beaches in 1995 also tested positive for 

 morbillivirus. The first animal, which was found on 

 21 August 1995 near Marina Del Ray, appears to 

 have recovered and is being held by Sea World of 

 California, pending determination of when such 

 animals might be returned to the wild with no risk of 

 transmitting the virus to uninfected animals. The 

 second dolphin stranded at Newport Beach, Califor- 

 nia, on 8 December 1995 and was euthanized. These 

 were the first indications of morbillivirus infections in 

 Pacific cetaceans. 



Brucellosis and Leptospirosis 



As part of ongoing studies of harbor seals in 

 Washington State waters, the Washington Department 

 of Fish and Wildlife collected and tested blood sam- 

 ples from 62 harbor seals for evidence of brucellosis 

 and leptospirosis infections. Thirteen of the 62 blood 

 samples tested positive for Brucella, a bacterium 

 known to affect cattle and humans. Twenty-four of 

 the 62 blood samples tested positive for Leptospira 

 gripptophosa, a spirochete not previously found in 

 west coast pinnipeds. By the end of 1995 there were 

 no indications of unusually high mortalities in the 

 affected population. 



The Regional Marine Mammal 

 Stranding Networks 



Much can be learned from stranded marine mam- 

 mals. For example, changes in the locations and 

 frequency of strandings may indicate changes in the 

 distribution and size of coastal marine mammal 

 populations. Similarly, the types and levels of envi- 

 ronmental contaminants found in tissues from stranded 

 marine mammals, coupled with stranding rates, may 

 be a good indicator of the health of marine ecosys- 

 tems. Stranded marine mammals also can help identi- 

 fy regional marine mammal conservation issues. For 

 example, examination of dead stranded harbor por- 

 poises provided the first indication of their mortality 

 in coastal fisheries (see Chapter III). 



In 1977 the Marine Mammal Commission spon- 

 sored a workshop to determine how data obtained 

 from both live and dead stranded marine mammals 

 might contribute to the conservation of marine mam- 

 mals and their habitat. The workshop participants 

 described data that should be obtained from stranded 

 amimals. They recommended that regional stranding 

 networks be organized to obtain and disseminate such 

 data (see Appendix B, Geraci and St. Aubin 1979). 



In response to the workshop, the National Marine 

 Fisheries Service established regional stranding 

 networks in the northeast (Maine to Virginia), the 

 southeast (North Carolina to Texas, Puerto Rico, and 

 the U.S. Virgin Islands), the southwest (California 

 and Hawaii), the northwest (Oregon and Washington), 



158 



