BC Conservation Data Centre: Conservation Status Report
Orcinus orca pop. 5
Killer Whale (Northeast Pacific Southern Resident Population)
| Scientific Name: | Orcinus orca pop. 5 |
|---|---|
| English Name: | Killer Whale (Northeast Pacific Southern Resident Population) |
| Provincial Status Summary | |
| Status: | S1 |
| Date Status Assigned: | March 18, 2011 |
| Date Last Reviewed: | March 31, 2021 |
| Reasons: | The southern resident killer whale population is extremely small (42 mature individuals in 2020), has declined by 24% over the past 25 years, and is vulnerable to a variety of threats, especially insufficient prey availability. |
| Range | |
| Range Extent: | FG = 20,000-2,500,000 square km |
| Range Extent Estimate (km2): | 220,000 |
| Range Extent Comments: | Occurs throughout coastal waters surrounding southern Vancouver Island, rarely offshore of continental slope. They are uncommon off northern Vancouver Island and have only rarely been encountered in more northern waters. There have been two sightings off Langara Island, Haida Gwaii, and one sighting in Chatham Strait, SE Alaska. The southern extent of their range is Monterey Bay, California (COSEWIC 2008, Ford 2014). The range extent is an estimated 220,000 kmē (COSEWIC 2008). |
| Area of Occupancy (km2): | I = >12,500 |
| Area of Occupancy Estimate (km2): | 99,549 |
| Area of Occupancy Comments: | Southern resident killer whales show broad seasonal variation in habitat use, related to the distribution of their principal prey, Chinook salmon. During summer and fall, they mostly frequent inshore waters off both the eastern and western sides of southern Vancouver Island. In winter and spring, most southern residents are found in outer coast areas, particularly off southwest Vancouver Island, although they may also be found in the Strait of Georgia. Outside of British Columbia waters, they occur in outer coast waters of the US mainland as far south as northern California (Ford et al. 2017). The area of occupancy is estimated to be 99,549 kmē using 2x2 grids (COSEWIC 2008). |
| Occurrences & Population | |
| Number of Occurrences: | B = 6 - 20 |
| Comments: | Resident killer whales are highly mobile and groups may travel distances of >100 km per day in search of Chinook salmon, their primary prey. However, they tend to concentrate seasonally in several locations along the BC coast where foraging for this prey species is particularly profitable. These include waters of the Strait of Georgia, Haro Strait, Swanson Channel, Boundary Pass, Juan de Fuca Strait, and Swiftsure Bank. These areas represent the minimum number of occurrences for this population (Ford 2006, Ford et al. 2010, 2018) |
| Number of Occurrences with Good Viability / Ecological Integrity: | Rank Factor not assessed |
| Number of Occurrences Appropriately Protected & Managed: | C = 4 - 12 |
| Comments: | Several areas of important foraging habitat for southern resident killer whales have been designated for protection as Critical Habitat under Canada?s Species at Risk Act. These include the waters of southern Georgia Strait, Haro Strait, Boundary Pass, Swanson Channel, and the waters of Swiftsure and La Perouse Banks off the southwest coast of Vancouver Island. In 2020, Fisheries and Oceans Canada and Transport Canada implemented a number of measures to protect southern resident killer whales and their habitat (DFO 2020). Area-based fishery closures and restrictions on boating during summer and fall were made in Swanson Channel, Boundary Pass, and portions of Juan de Fuca Strait. In addition, a mandatory 400-metre minimum vessel approach distance for all killer whales was imposed in southern British Columbia coastal waters between Campbell River and just north of Ucluelet (J. Ford, pers. comm. 2021). |
| Population Size: | A = 1 - 50 individuals |
| Comments: | As of 2020, there were 42 mature individuals, not including post-reproductive females (total population size was 74) (Center for Whale Research, pers. comm.; Cetacean Research Program, DFO, unpubl. data). |
| Threats (to population, occurrences, or area affected) | |
| Degree of Threat: | AB = Very high - high |
| Comments: | The three main threats to southern resident killer whales are 1) inadequate prey availability, 2) acoustic and physical disturbance from vessels and other industrial activities, and 3) elevated levels of environmental contaminants (DFO 2018; Murray et al. 2019; Washington State Academy of Sciences 2020). Resident killer whales are salmon-specialist predators that feed primarily on Chinook and secondarily on chum salmon and other salmonids. Long-term studies have shown a strong relationship between Chinook salmon abundance and survival and reproductive rates in this population (Ford et al. 2009, 2010). Chinook salmon stocks have declined significantly in recent decades, especially in the 1990s. Overall productivity of Chinook salmon populations has declined by 25-40% since the 1980s, and there is also a significant trend in declining body size (and thus energetic value) (Murray et al. 2019). The majority of chum salmon stocks in BC have also experienced declines in productivity. Another important threat is underwater noise and disturbance from vessels and other anthropogenic sources. Noise can potentially cause auditory masking of the whales? communication signals needed for coordination of group activities and also their echolocation, which they use to detect and capture prey. The long-term effects of underwater noise are uncertain. Vessel movements and congestion near whales may disrupt life processes such as resting and foraging, as well as increasing risk of vessel strikes. Several mortalities of resident killer whales in recent years have been attributed to blunt force trauma, likely from collision by vessels (Murray et al. 2019; Raverty et al. in press). Killer whales are susceptible to environmental contaminants such as PCBs and other organochlorines, which bioaccumulate upward through the marine food web and are stored in the whales? blubber. Potential effects of these contaminants include reduced reproductive success and immunosuppression, which may become acute during periods of inadequate prey availability and subsequent metabolism of fat reserves (Wiles 2016). Other threats include mortality from oil spills and interaction with fisheries (e.g., ingestion of fish hooks, entanglement in gear) (DFO 2018). |
| Trend (in population, range, area occupied, and/or condition of occurrences) | |
| Short-Term Trend: | F = Decline of 10-30% |
| Comments: | Abundance of southern resident killer whales has been censused by individual photo-identification each year since 1974. In the decade prior to the first census, an estimated 47 or 48 whales were live captured from this population for public display or died in capture operations (Wiles 2004). Thus, the population was depleted in 1974 when the first census tallied 71 animals. Between 1974 and 1997, the population grew at an average 1.6% per annum and reached a peak of 98 individuals in 1995. Since then, although there have been some years of increase, the population has declined by 24% to 74 whales in 2020. |
| Long-Term Trend: | U = Unknown |
| Comments: | The historical abundance of southern resident killer whales is unknown, but it may have been larger than at present. Resident killer whales are specialist apex predators that may be limited by abundance of their principal prey, Chinook salmon (Ford et al 2010; DFO 2018). Chinook stocks in major river systems such as the Fraser, Columbia and Sacramento were substantially larger in the 19th century than today, and may have supported larger numbers of southern resident killer whales (Hilborn et al. 2012). |
| Other Factors | |
| Intrinsic Vulnerability: | Rank Factor not assessed |
| Environmental Specificity: | Rank Factor not assessed |
| Other Rank Considerations: | |
| Information Gaps | |
| Research Needs: | A wide range of studies have been identified as priorities for this population in DFO?s Action Plan (DFO 2017), including: assessing winter distribution and diet; estimating the carrying capacity of the population?s habitat; determining the effects of underwater noise and vessel disturbance on foraging success and other behaviours; determining the impacts of Persistent Organic Pollutants (POPs, e.g. PCB) on immune response and fecundity; etc. |
| Inventory Needs: | For over 45 years, the population has been censused annually by photo-identification of whales using natural markings. This has led to a registry of all individuals, including years of birth and death, sex, age of reproduction in females, etc., maintained by DFO Science at the Pacific Biological Station and the Center for Whale Research in Washington state. It is important that this annual census effort be continued to monitor population trends. |
| Stewardship | |
| Protection: | Killer whales are protected under the federal Marine Mammal Regulations of the Fisheries Act as well as the Species at Risk Act. The Marine Mammal Regulations were amended in 2018 to increase the minimum approach distance to killer whales from 100 m to 200 m as a measure to mitigate potential disturbance, and this was doubled to 400 m in 2020 for southern British Columbia coastal waters between Campbell River and just north of Ucluelet. |
| Management: | DFO Science has recently produced a cumulative effects population viability analysis model for northern and southern resident killer whales, incorporating potentially interacting effects of prey abundance, vessel noise/presence, vessel strike risk, and bioaccumulating contaminants (Murray et al. 2019). This may be a useful tool in future management considerations and decisions. New management recommendations for southern resident killer whales have also recently been developed in Washington state (Washington State Academy of Sciences 2020). |
| Version | |
| Author: | J. Ford (2021) Ramsay, L., A. Teucher (previous versions) |
| Date: | November 17, 2020 |
| References | |
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Ford, J.K.B, Wright, B.M., Ellis, G.M., et al. 2010. Chinook salmon predation by resident killer whales: seasonal and regional selectivity, stock identity of prey, and consumption rates. DFO Can. Sci. Advis. Sec. Res. Doc. 2009/101. iv + 43 p. |
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Canada Gazette. 2018. Regulations Amending the Marine Mammal Regulations: SOR/2018-126. Part II, Volume 152, Number 14
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COSEWIC. 2008v. COSEWIC assessment and update status report on the Killer Whale Orcinus orca, Southern Resident population, Northern Resident population, West Coast Transient population, Offshore Population and Northwest Atlantic / Eastern Arctic population, in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. viii + 65 pp.(www.sararegistry.gc.ca/status/status_e.cfm).
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Fisheries and Oceans Canada. 2017. Action Plan for the Northern and Southern Resident Killer Whale (Orcinus orca) in Canada. Species at Risk Act Action Plan Series. Fisheries and Oceans Canada, Ottawa. v + 33 pp.
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Fisheries and Oceans Canada. 2019. Population Status Update for the Northern Resident Killer Whale ( Orcinus orca ) in 2018. DFO Can. Sci. Advis. Sec. Sci. Resp. 2019/025
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Fisheries and Oceans Canada. 2020d. Management measures to protect Southern Resident killer whales.
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Ford, J.K.B, G.M. Ellis, P.F. Olesiuk, et al. 2010. Linking killer whale survival and prey abundance: food limitation in the oceans? apex predator? Biology Letter 6:139-142. Published on-line before print September 15, 2009.
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Ford, J.K.B. 2006. An Assessment of Critical Habitats of Resident Killer Whales in Waters off the Pacific Coast of Canada. DFO Can. Sci. Advis. Sec. Res. Doc. 2006/72 iv + 32 pp.
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Ford, J.K.B. 2014. Marine Mammals of British Columbia. Royal BC Museum Handbook, Mammals of BC, volume 6. Royal B.C. Mus., Victoria, BC. 460 pp.
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Ford, J.K.B., Pilkington, J.F., Reira, A., et al. 2017. Habitats of special importance to Resident Killer Whales (Orcinus orca) off the west coast of Canada. DFO Can. Sci. Advis. Sec. Res. Doc. 2017/035. viii + 57 p
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Hilborn, R., S.P. Cox, F.M.D. Gulland, et al. 2012. The Effects of Salmon Fisheries on Southern Resident Killer Whales: Final Report of the Independent Science Panel. Prepared with the assistance of D.R. Marmorek and A.W. Hall, ESSA Technologies Ltd., Vancouver, B.C. for National Marine Fisheries Service (Seattle. WA) and Fisheries and Oceans Canada (Vancouver. BC). xv + 61 pp. + Appendices.
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Murray, C.C., Hannah, L.C., Doniol-Valcroze, T.,et al. 2019. Cumulative Effects Assessment for Northern and Southern Resident Killer Whale Populations in the Northeast Pacific. DFO Can. Sci. Advis. Sec. Res. Doc. 2019/056. x. + 88p.
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Raverty, S. J. St. Leger, D.P. Noren, et al. 2020. Pathology findings and correlation with body condition index in stranded killer whales (Orcinus orca) in the northeastern Pacific and Hawaii from 2004 to 2013. PLOS One. 15(12): e0242505.
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Washington State Academy of Sciences. 2020. Summary of Key Research Findings about Underwater Noise and Vessel Disturbance. Seattle, WA: WSAS, 1-25.
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Wiles, G. 2016. Periodic status review for the killer whale in Washington. Washington Department of Fish and Wildlife, Olympia, Washington. 26+iii pp.
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Please visit the website Conservation Status Ranks for information on how the CDC determines conservation status ranks. For global conservation status reports and ranks, please visit the NatureServe website http://www.natureserve.org/.
Suggested Citation:
B.C. Conservation Data Centre. 2020. Conservation Status Report: Orcinus orca pop. 5. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Jun 9, 2026).