Transient orca in the San Juan islands
Three ecotypes of killer whales regularly occur in Washington: fish-eating residents, mammal-eating transients (or Bigg’s), and offshores. The Southern Resident population has shown an overall declining trend since 1995, falling from 98 whales to 73 whales as of December 2021, and is federally listed as endangered in the U.S. and Canada. The transient and offshore populations are stable or increasing, although the species is broadly listed as endangered in Washington state due to the status of the imperiled Southern Residents.
Reduced availability of Chinook salmon, elevated marine contaminants, and noise and disturbance from vessel activity have limited the Southern Resident population’s productivity. Increased shipping traffic and the associated threat of large oil spills also have the potential to negatively impact the health and status of all three populations.
Marine mammals are protected under the Marine Mammal Protection Act. To report a dead, injured or stranded marine mammal, please call the National Oceanic and Atmospheric Administration (NOAA) West Coast Region Stranding Network hotline: 1-866-767-6114.
Description and Range
Physical description
Killer whales are the largest member of the oceanic dolphin family. This species may weigh up to 11 tons and be up to 32 feet long. They are mostly black with white eyebrow patch, and white underside extending from throat to tail, including flanks.
Ecology and life history
Killer whales occupy pelagic and coastal (including inland marine) waters. Southern Resident and transient killer whales spend more time in coastal areas, where their preferred prey is typically found. The Southern Resident population feeds primarily on Chinook salmon, chum salmon to a lesser extent, and occasionally other fish. Transient animals feed on seals and other marine mammals. Offshore animals primarily feed on sharks and other fish.
Killer whales become sexually mature at about 12 to 16 years of age. Females have calves every three to eight years and become reproductively senescent when 35 to 45 years old. The estimated maximum lifespan is 80 to 90 years for females and 50 to 60 years for males.
Geographic range
Killer whales are distributed nearly worldwide. In Washington, they occur in most of the state's marine waters.
Only small portions of both transient and offshore populations normally occur in Washington at any one time. The Southern Resident population is comprised of three highly stable social groups (J, K, and L pods) that historically has inhabited waters around the San Juan Islands and the eastern Strait of Juan de Fuca from late spring to fall. These patterns appear to be changing in recent years, with Southern Residents spending less time in Puget Sound.
Transients are part of a single population ranging from southeastern Alaska to California. In contrast to the Southern Resident population, the west coast transient population has shown considerable growth since the 1970s in response to the recovery of its marine mammal prey base and is now estimated to number more than 500 whales and be near carrying capacity.
Offshore killer whales are much less studied, but also form one population extending from southeastern Alaska to California. These whales usually occur more than nine miles off the outer coast. Offshore killer whales are estimated at 300 individuals and have a stable population trend.
For worldwide distribution of killer whales and other species' information, check out NatureServe Explorer.
Climate vulnerability
Sensitivity to climate change
Climate change will likely impact all three ecotypes of killer whales (Southern Residents, transients, offshores) in Washington. This will occur mainly through alterations in prey abundance (i.e., availability of Chinook salmon, marine mammals, sharks, and other prey) resulting from (1) changes in marine food webs, (2) alterations in freshwater habitats occupied by salmon (for Southern Residents), and (3) rising sea level, which may submerge or render unsuitable some traditional pinniped rookeries and haulouts (for transients), and some nearshore habitats required by salmon (for Southern Residents). These impacts will likely result from increases in marine and freshwater temperature, increases in ocean acidification, and altered levels of terrestrial precipitation and runoff. Southern Resident whales are specialists on Chinook salmon, which are themselves quite vulnerable to climate change.
Exposure to climate change
- Increased ocean and freshwater temperatures
- Increased ocean acidification
- Sea level rise
- Increased precipitation
Conservation
Conservation Threats and Actions Needed
All three populations of killer whale occurring in Washington carry heavy loads of environmental contaminants, face a continuing risk of major oil spills in their ranges, are susceptible to a disease outbreak, and will likely experience the impacts of climate change in the future.
Climate vulnerability is a way to assess the degree to which a habitat or species is susceptible to, and unable to cope with adverse impacts of climate change. Climate vulnerability ranking for Southern Residents is high, and for transients and offshore whales is moderate. Climate sensitivity is a measure of whether and how a resource is likely to be affected by a given change in climatic factors. Sensitivity ranking for Southern Residents is high, and for transients and offshore whales is moderate. Climate exposure is a measure of how much of a change in climate or climate-driven factors a resource is likely to experience. Exposure ranking for Southern Residents is moderate to high, and for transients and offshore whales is moderate. For more information about ranking methods, see the 2015 State Wildlife Action Plan’s Chapter 5 - Climate Change Vulnerability of Species and Habitats in Washington. See the Climate vulnerability section above for more detailed information about the threats posed by climate change to this species.
- Overharvesting of biological resources
- Threat: Depleted populations of Chinook salmon reduce prey availability for the Southern Residents, limiting the population’s productivity.
- Action Needed: Rebuild depleted populations of Chinook salmon through multiple restoration activities, including management of habitat, harvest, hydropower, and hatcheries.
- Outreach needs
- Threat: Noise and disturbance from vessels and other human activities has the potential to disrupt foraging and other behavior by the Southern Resident population.
- Action Needed: Minimize disturbance from vessels by continued evaluation and enforcement of regulations and guidelines protecting killer whales from vessel noise and disturbance.
- Fish and wildlife habitat loss or degradation
- Threat: High levels of chemical contaminants continue to exist in Southern Resident whales and may be causing health impacts.
- Action Needed: Minimize pollution levels in aquatic habitats.
- Energy development and distribution
- Threat: Large oil spills could harm killer whale populations through negative impacts to health.
- Action Needed: Minimize the risk of oil spills in Washington and elsewhere along the west coast of North America. Keep oil spill response plans updated.
Our Conservation Efforts
Washington’s Governor Inslee issued an executive order in 2018, directing state resources toward Southern Resident Killer Whale (SRKW) recovery. The order also assembled the Southern Resident Orca Task Force, bringing together tribal, federal, state and local representatives with members of private and non-profit sectors. That two-year effort resulted in a comprehensive report detailing 49 recommendations, targeting the three main categories of threats. Many resources and management activities have derived from those recommendations, including in Washington:
- salmon management and recovery
- steps to enhance oil spill prevention and response, and to deter whales away from spills
- measures to reduce the input of environmental contaminants into marine waters
- public outreach
- preparation of conservation plans
- 2020 update of federal critical habitat for Southern Residents
- implementation and enforcement of new speed and distance regulations for all vessels around Southern Residents and a commercial whale-watching license program with additional rules for watching Southern Residents
- evaluation of Chinook salmon abundance and impacts of marine fisheries on the Southern Residents
Nevertheless, expanded actions will very likely be needed to achieve recovery of the southern residents.
Visit our Killer Whale Management and Conservation page for more information, including how you can help.
Resources
References
Caretta, J.V., E.M. Oleson, K.A. Forney, M.M. Muto, D.W. Weller, A.R. Lang, J. Baker, B. Hanson, A.J. Orr, J. Barlow, J.E. Moore, and R.L. Brownell Jr. 2021. U.S. Pacific Marine Mammal Stock Assessments: 2020. U.S. Department of Commerce, NOAA Technical Memorandum NMFS-SWFSC-646.
Muto, M.M., V.T. Helker, B.J. Delean, R.P. Angliss, P.L. Boveng, J.M. Breiwick, B.M. Brost, M.F. Cameron, P.J. Clapham, S.P. Dahle, M.E. Dalheim, B.S. Fadely, M.C. Ferguson, L.W. Fritz, R.C. Hobbs, Y.V. Ivashchenko, A.S. Kennedy, J.M. London, S.A. Mizroch, R.R. Ream, E.L. Richmond, K.E.W. Shelden, K.L. Sweeney, R.G. Towell, P.R. Wade, J.M. Waite, and A.N. Zerbini. 2020. Alaska Marine Mammal Stock Assessments, 2019. U.S. Department of Commerce. NOAA Technical Memorandum NMFS-AFSC-404, 395 p.
National Marine Fisheries Service. 2008. Recovery Plan for Southern Resident Killer Whales (Orcinus orca). National Marine Fisheries Service, Northwest Region, Seattle, Washington.
Wiles, G. J. 2016. Washington state status report for the killer whale. Washington Department of Fish and Wildlife, Olympia, Washington.
WDFW publications
- Washington State Periodic Status Review for the Killer Whale (Orca) (2016)
- Washington State Status Report for the Killer Whale (Orca) (2004)
- Evaluating Salmon Harvest Effects on Southern Resident Killer Whales in Washington State (2019)