Three populations of killer whales, known as the southern residents, transients, and offshores, regularly occur in Washington. The southern residents are listed as federal endangered species, but all three populations are state endangered species.
Of the three main populations occurring in Washington, southern resident killer whales have shown an overall decline since 1995, whereas transient and offshore populations are currently not of conservation concern. The reduced availability of depleted Chinook salmon populations has limited the southern resident population’s productivity. High levels of chemical contaminants, noise and disturbance from vessels and other human activities, as well as large oil spills all 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 Marine Mammal Stranding Network hotline: 1-866-767-6114.
Description and Range
Killer whales are the largest member of the oceanic dolphin family. This species may weigh up to 11 tons and length may be up to 32 feet. 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 waters. Southern resident and transient killer whales spend more time in coastal areas (including inland marine waters), 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.
All killer whales become sexually mature at about 12 to 16 years of age. Females become reproductively senescent when 35 to 45 years old. The calving interval is about three to eight years.
This lifespan of this species ranges from 30 to 90 years. The estimated maximum lifespan is 80 to 90 years for females and 50 to 60 years in males.
Killer whales are distributed nearly worldwide. In Washington, they occur in most of the state's marine waters.
Three populations of killer whales, known as the southern residents, transients, and offshores, regularly occur in Washington. Only small portions of both transient and offshore populations normally occur in Washington at any one time. The southern resident population has shown an overall declining trend since 1995, falling from 98 whales to 81 whales as of July 2015. They are the population of greatest concern. The southern resident population is comprised of three highly stable social groups (J, K, and L pods) and commonly inhabits waters around the San Juan Islands and the eastern Strait of Juan de Fuca from late spring to fall. Most of the rest of the year is spent along the outer coast. While numbers have been relatively stable since 2001, they remain 17 percent below their recent peak size recorded in 1995.
Transient animals 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 its 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.
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 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. See the Climate vulnerability section above for 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, thereby 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.
Our Conservation Efforts
Various management activities have been taken since 2004 that directly or indirectly benefit killer whales in Washington, many of which are aimed at the southern residents. These include:
- the preparation of conservation plans
- designation of federal critical habitat for southern residents
- implementation and enforcement of new whale-watching regulations
- evaluation of Chinook salmon abundance and marine fisheries on the southern residents
- population monitoring and research
- public outreach
- 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
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.
- Washington State Periodic Status Review for the Killer Whale (Orca) (2016)
- Washington State Status Report for the Killer Whale (Orca) (2004)