Center for Biological Diversity

Protecting endangered species and wild places of western North America
and the Pacific through science, policy, education, and environmental law.

July 18, 2001
CONTACT: Dr. Martin Taylor 520-623-5252 ext 307


CBD's Orca page
updated Population Viability Analysis

In the light of the recent deaths of seven killer whales, Dr Martin Taylor, population biologist with the Center for Biological Diversity, has updated his computerized population viability model of the "Southern Resident" killer whales in the Puget Sound. In addition to the escalated death rate, the updated model incorporates the impacts of reduced food supply and potential disease outbreaks and oil spills.

The most realistic of the many scenarios modeled shows a 95% chance of extinction in 33 to 121 years, with a median of 74 years. This model predicts certain extinction within 150 years. Dr. Taylor's analysis also demonstrates, however, that if the environment is sufficiently protected, the killer whales have a good chance of surviving for at least another 300 years.

"If governments take immediate action to reverse the growing threats from pollutants, oil spills, salmon loss and unregulated boat traffic, then the whales can be saved. If the threats are allowed to go on, the whales are sure to go extinct. Our grandkids may never be able to see a wild, living whale and will ask themselves, why didn't they do something back then?" said Dr Taylor.

Dr. Taylor has recently returned from participating in a scientific workgroup of the International Whaling Commission to help conduct a global assessment of habitat threats to whales and dolphins. His population viability analysis is the first computer model to quantitatively incorporate habitat threats into a whale population trend projection. A similar analysis done for the northern spotted owl resulted in its being listed as an endangered species in the Pacific Northwest.

Adult whale survival rates have shown a significant downward trend in the past 26 years. A steep population decline since 1996 has reduced the population from 97 to 78 whales. Ongoing degradation of the whales' habitat is the presumed cause of the population decline. There has been a sharp reduction in salmon stocks, the preferred food of the whales, which may be forcing the whales to hunt further from home where they may face greater risk of death from fishing nets and gear. The whales also suffer high body burdens of organo-chlorine pollutants from industrial dumps throughout the area. These pollutants depress immune function and leave the whales open to microbial disease outbreaks. The expansion of oil facilities in Puget Sound will expose whales to greater risks of death from oil spills. In recent years there has also been a sharp increase in unregulated whale watching and other shipping traffic.
The National Marine Fisheries Service is currently reviewing a petition to list the killer whales as endangered, which was filed by the Center for Biological Diversity with co-petitioners Center for Whale Research, the Whale Museum, the American Cetacean Society, Ocean Advocates, Orca Conservancy, People for Puget Sound, Friends of the San Juans, the Cascade Chapter of the Sierra Club, the Washington Toxics Coalition, Project Seawolf, and former Washington Secretary of State Ralph Munro.


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