BC Conservation Data Centre: Conservation Status Report
Zalophus californianus
California Sea Lion
| Scientific Name: | Zalophus californianus |
|---|---|
| English Name: | California Sea Lion |
| Provincial Status Summary | |
| Status: | S4S5N |
| Date Status Assigned: | March 03, 2022 |
| Date Last Reviewed: | March 03, 2022 |
| Reasons: | California Sea Lions occur throughout BC waters. They use numerous haul-outs along the coast, but they do not breed in BC. Populations have been increasing over the past 42 years; however, they are still subject to threats including shooting due to fishery conflicts, mortality in fishing gear and entanglement in debris. Changes in the ecosystem can also threaten California Sea Lions. For example, warm water events can reduce the survival of young. |
| Range | |
| Range Extent: | FG = 20,000-2,500,000 square km |
| Range Extent Estimate (km2): | 65,000 |
| Range Extent Comments: | California Sea Lions have been observed throughout BC coastal waters. Their range extent in BC is likely similar to that of Steller Sea Lion, which is estimated to be approximately 65,000 km squared (COSEWIC 2013). |
| Linear Distance of Occupancy: | U = Unknown |
| Area of Occupancy Comments: | The Area of Occupancy may consist of the numerous haul-out sites used by the species in BC, the total area of which is unknown. California Sea Lions do not breed in BC, hence the Area of Occupancy does not include rookeries as in Steller Sea Lion. |
| Occurrences & Population | |
| Number of Occurrences: | D = 81 - 300 |
| Comments: | The number of occurrences are based on haulouts sites, of which there are at least 150 documented in BC (Ford 2014). Most are along the west coast of Vancouver Island and in the Strait of Georgia, with some in Haida Gwaii and on along the mainland coast. They are mostly used seasonally from October through April or May. |
| Number of Occurrences with Good Viability / Ecological Integrity: | Rank Factor not assessed |
| Percent Area with Good Viability / Ecological Integrity: | DF = Moderate to excellent (>10%) |
| Comments: | Most California Sea Lion haulouts in BC are in relatively remote areas with good ecological integrity. |
| Number of Occurrences Appropriately Protected & Managed: | C = 4 - 12 |
| Comments: | Some haulouts around Vancouver Island are protected, including Race Rocks Ecological Reserve and various locations within Pacific Rim National Park. The great majority are not protected. |
| Population Size: | DE = 1,000 - 10,000 individuals |
| Comments: |
California Sea Lions are seasonally present in BC waters. Male sea lions migrate north from California in fall and are found in BC mostly from October to April or May. Females typically do not migrate north of California (Ford 2014). The most recent survey of California Sea Lions in BC, conducted in 2008-2010, resulted in a count of 1,806 individuals. If haul-out patterns are similar to those of Steller Sea Lions, corrections for California Sea Lions at sea and missed during surveys suggest a total population of about 6,300 in 2008-2010 (Olesiuk 2012). Assuming that life history parameters are similar to those of Steller Sea Lions, about 40% of the overall California Sea Lion population would be mature. However, it is likely that a greater proportion of animals that migrate to BC in winter are mature, since young nursing pups remain in California waters. However, that proportion cannot be accurately estimated using existing information, but it can be assumed that at least 50% are mature. There has not been a dedicated survey for California Sea Lions in BC since 2008-2010. However, a partial sea lion survey in 2012 documented about 10,000 California Sea Lions, mostly on haulouts in Barkely Sound and on Perez Rocks off Hesquiat Peninsula (Ford 2014). The most recent abundance estimate for the entire California Sea Lion population along the US west coast is about 233,000 individuals in 2014 (all ages; Carretta et al. 2021). In addition to this, a further 100,000 animals were estimated around Baja California, Mexico, in 2010 (Aurioles-Gamboa and Hernández-Camacho 2015). |
| Threats (to population, occurrences, or area affected) | |
| Degree of Threat: | CD = Medium - low |
| Comments: |
The threats to California Sea Lions are in two broad categories: 1) anthropogenic and 2) natural changes in the ecosystem. The main anthropogenic threats include intentional shooting (mostly resulting from fishery conflicts), incidental mortality in fishing gear, and entanglement in debris (Aurioles-Gamboa and Hernández-Camacho 2015; Carretta et al. 2021; Ford 2014). Intentional shooting of California Sea Lions at aquaculture sites was, until recently, a significant source of mortality in BC with 224 animals killed in 2011 alone. Since then, improved management practices and non-issuance of nuisance seal and sea lion removal licences by DFO aver 2020 have essentially eliminated this threat (DFO 2022). A significant potential future threat to California Sea Lions in BC is culling to mitigate perceived impacts of competition with recreational and commercial fisheries (e.g. Pynn 2020; Davis 2022). Ecosystem change driven by warm water events (e.g., El Niño, marine heatwaves) is a significant natural threat. Such events led to increased pup and juvenile mortality caused by reduced prey availability during the marine heatwave of 2013-2017. It has been estimated that for each 1°C increase in seawater temperature, California Sea Lion pup and yearling survival decreases by 50% (Carretta et al. 2021). |
| Trend (in population, range, area occupied, and/or condition of occurrences) | |
| Short-Term Trend: | I = Increase of >25% |
| Comments: | The number of California Sea Lions migrating into BC waters for the winter has fluctuated widely over the past 42 years (3 generations at 14 yrs/generation (Pacifici et al. 2013). California Sea Lions were rarely seen in BC prior to 1970. After that, numbers increased dramatically, from a few hundred in the early 1970s to about 4,500 in 1984. The average abundance in the 1980s was 2,646 (range 1,518-4,478), which declined to 1,580 (range 1,185-1,901) in the 2000s. In the most recent province-wide winter sea lion survey in B.C. during 2008-2010, a total of 1,806 California sea lions were counted (Olesiuk 2012). An unusually large abundance of about 10,000 was estimated in 2012. The year-to-year variability in California Sea Lion numbers can be seen in their use of an important winter haulout at Race Rocks (Edgell and Demarchi 2012). Much of this variability appears to be driven by prey availability (Edgell and Demarchi 2012). The Pinniped Research Program at the Pacific Biological Station is currently undertaking a dedicated coast-wide survey to update abundance numbers (S. Majewski, pers. comm. 2022). |
| Long-Term Trend: | I = Increase of >25% |
| Comments: | The species was hunted for subsistence by Nuu-chah-nulth First Nations prior to the arrival of Europeans (McKechnie and Wigen 2011) but remains are not as common in middens as Harbour Seals, Northern Fur Seals or Steller Sea Lions. With the arrival of Europeans, California Sea Lions were hunted extensively in California and Mexico for oil, hides, pet food, and predator control. This drove abundance down to as few as 1,500 animals by the 1920s (Ford 2014). Market factors and protection put an end to widespread killing and the population began expanding by the 1940s. The overall population is now about 238,000 in California (Ford 2014), and perhaps 6,000 or more in BC. Thus, abundance has increased > 25% over the past century. |
| Other Factors | |
| Intrinsic Vulnerability: | Rank Factor not assessed |
| Environmental Specificity: | Rank Factor not assessed |
| Other Rank Considerations: | |
| Information Gaps | |
| Research Needs: | |
| Inventory Needs: | |
| Stewardship | |
| Protection: | |
| Management: | |
| Version | |
| Author: | Ford, J.k |
| Date: | March 03, 2022 |
| References | |
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Edgell, T.C. and M.W. Demarchi. 2012. California and Steller sea lion use of a major winter haulout in the Salish Sea over 45 years. Marine Ecology Progress Series, 467: 253?262 |
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McKechnie, I. and R. J. Wigen. 2011. Toward a Historical Ecology of Pinniped and Sea Otter Hunting Traditions on the Coast of Southern British Columbia. Pages 129-165 in T. J. Braje and T. C. Rick, editors. Human Impacts on Seals, Sea Lions, and Sea Otters: Integrating Archaeology and Ecology in the Northeast Pacific. University of California Press, Berkeley. |
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Olesiuk, P. 2012. Status of sea lions (Eumetopias jubatus and Zalophus californianus) wintering in British Columbia. Unpubl. working paper. Available from Pacific Biological Station, DFO, Pinniped Research Program. |
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Pynn, L. 2020. What Would a British Columbia Seal and Sea Lion Cull Actually Entail? Hakai Magazine, 22 October 2020 |
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Aurioles-Gamboa, D. and J. Hernández-Camacho. 2015.Zalophus californianus.;The IUCN Red List of Threatened Species 2015: e.T41666A45230310.
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Carretta, J.V., E.M. Oleson, K. Forney et al. 2021. US Pacific marine mammal stock assessments: 2020. U.S. Department of Commerce, NOAA Technical Memorandum NMFS-SWFSC-646.
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COSEWIC. 2013d. COSEWIC assessment and status report on the Steller Sea Lion Eumetopias jubatus in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. xi + 54 pp.
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Davis, T. 2022. Seals & Sea Lions: Success or Disaster. Island Fisherman Magazine, Victoria, BC. January, 2022.
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DFO (Department of Fisheries and Oceans). 2022. Marine mammal (megafauna) fatalities at marine finfish aquaculture facilities in British Columbia. (accessed on-line March 2022).
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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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Pacifici, M., L. Santini, M. Di Marco et al. 2013. Generation length for mammals. Nature Conservation 5, pp.89-94.
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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. 2022. Conservation Status Report: Zalophus californianus. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Jun 8, 2026).