Northwest Fisheries Science Center

Southern Resident Killer Whales

Killer whales (Orcinus orca), or orca, are toothed whales, related to sperm and pilot whales, with a worldwide distribution. Southern Resident killer Whales (SRKW) are an iconic species in the Pacific Northwest, spending several months during summer and fall in Washington’s San Juan Islands and Puget Sound where they feed primarily on salmon. This population was reduced dramatically in the 1960s and 1970s by marine park captures, when the population reached a low of 71 individuals. Although the population grew into the 1990s, it currently numbers only in the 80s.

In 2005, NOAA Fisheries designated Southern Resident killer whales as ‘endangered’ due to their low abundance and variety of threats to their persistence. Specifically, there are currently only a few reproductive-age males in the population, and several females of reproductive age are not having calves. Potential factors affecting their decline or limiting their recovery are: quantity and quality of prey; toxic chemicals which ac­cumulate in top predators, and disturbance from sound and vessel traffic. Oil spills are also a potential risk factor.

NOAA Fisheries finalized a recovery plan for SRKWs in 2008, and our scientists are leading the effort to understand the factors potentially limiting this population. Our research addresses key questions that must be answered to successfully conserve this endangered species, including studies about their taxonomy, behavior, ecology, health, and human-caused impacts. Our work helps NOAA's West Coast Region implement the Endangered Species Act and Marine Mammal Protection Act and inform species recovery and management actions.



Past Workshops and Symposia


Special Report


  • image of killer whale
    View images of Southern Resident killer whales.

  • Watch the science behind the recovery of Southern Residents, from using satellite tags to analyzing DNA in whale poop. (Running time: 7 minutes)

Blogs & Expeditions

  • Follow the blogs of our researchers as they collect data on orcas and their ecosystem.