By Mary Mahon

 

About the Southern Resident Orcas     

 

Orcas can be found in every ocean around the world, and their distinct features, intelligence, and tight-knit social structures make them an iconic and beloved animal. Orcas have different ecotypes and a unique family structure, typically with the female as the leader of the pod. The female and male offspring will spend their life with their mother, while occasionally separating from the pod to socialize or breed. 

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The Southern Resident Killer Whales (SRKW) are a distinct population of Orcas that are genetically and culturally differentiated, found in the Pacific Northwest. They consist of several matrilines, including the J, L and K pods.

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Orcas are not only the largest of the Delphinidae (oceanic dolphins) family, but they’re also a top predator and a keystone species, meaning that they are an essential indicator of the health of the ecosystem. This is evident in the SRKW through the decline in population resulting from the decline in salmon populations, environmental pollutants, and high levels of noise disruption. This indicates that change needs to be made to recover the SRKW population and the ecosystem. Studies have shown that impacts on the SRKW have resulted in lower calf survival and a shortened lifespan in adult orcas, leading to a decline in the population. The SRKW status is currently listed as Critically Endangered, with an estimated population of 74.

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What are PCBs? 

 

Polychlorinated biphenyls (PCBs) are synthetic organic chemicals composed of carbon, hydrogen, and chlorine atoms. PCBs have been manufactured since 1929 and commercially used in various appliances, including electrical equipment, paints, plastics, and rubber. The manufacturing and import of PCBs were banned in Canada in 1977, and their release to the environment has been prohibited since 1985. PCBs were leaked into the environment through hazardous waste sites, dumping, leaks from electrical transformers and landfill. PCBs only break down in specific environments; however, PCBs have accumulated and absorbed into soil. 

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Although banned since 1977, PCBs are still used today and have not been fully depleted. As a result, PCBs released to the environment can be found in wildlife, including fish. Humans can also be exposed to levels of PCB consumption through eating fish, leading to several health concerns. PCB concentrations grow higher up the food chain; this is a process called bioaccumulation. As Orcas are top predators in the food chain, they have higher levels of PCBs stored in their blubber.

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Bioaccumulation of PCB in marine food chain. Photo credit: Washington Department of Ecology

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How have PCBs affected the Southern Resident Orcas? 

According to a report released to the Canadian Government by conservation organizations, the SRKW face several threats, including the high level of PCBs found in the environment, which potentially impacts their primary food source. There have been many stillbirths or infants not living for longer than a few days reported. PCBs are fat-soluble, and PCBs can be passed to offspring through the fat-rich milk. 

 

Most recently, in September 2025, the J pod faced the death of a new member of their family. The mother (J36) was seen pushing the dead calf for around 45 kilometres with the umbilical cord still attached. While the exact cause is not known, researchers have seen this before, and the low reproductive success of the SRKW is directly linked to the level of pollutants in the ocean, particularly PCBs. Researchers have predicted that the population of the SRKW could be declared extinct within the next 40 years if no action is taken. 

 

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​Southern Resident Killer Whale Population Details - Historical Demographics - Marine Mammal Commission

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Potential Solutions

While there have been some measures put in place by Canada in managing the stressors to the SRKW, including banning PCBs, management plans for Salmon, the Government of Canada’s Oceans Protection Plan & Whales Initiative, and cross-border agreements. A recommendations report released to the Canadian Government further outlines potential solutions for recovering the SRKW. 

Potential resolutions include: 

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Phase out and potential removal of PCBs:

• Although PCBs were banned in 1977, PCBs are still found and used in equipment. Responsible disposal of PCB materials can eliminate the pollutants from being used and continuing the buildup in the environment. 

• Responsible disposal of PCBs will need a strict plan and policy enforcement to ensure that the disposal does not cause further impact to the environment. 

 

Unfortunately, Seattle is not that far away, and although PCB production in the US was discontinued after 50 years, PCBs still remain in products produced between 1929 and 1979. The northwestern seaboard of the United States now has different environmental regulations in place due to the current administration. The Canada-US Boundary Waters Treaty of 1909 remains in place. It is intended to prevent the release of any products that could cause harm to humans. There is testing in the US, and most recently, a PCB clean-up in the Pacific Northwest appears to have been successful so far. However, it is still a relatively recent event, so its long-term impact is not yet known.

 

Water quality control:

• Active water quality control and quality testing in urbanized and industrial areas should be put in place. While there is currently a level of control and testing, further studies and consistent monitoring would be required to fully assess the effect and determine the necessary action. This is particularly critical in known areas of wastewater, runoff, and salmon runs, to continue conservation efforts that protect salmon and subsequently orcas. This leads to limiting the level of bioaccumulation. 

• Regulating water quality testing would need to be strictly monitored and would require noncompliance or data-deficient penalties to be enforced. To have continuous testing and monitoring would require expanding human capacity and funding to ensure the standards are maintained. 

 

Regulations are in place for disposing of PCBs safely through registered hazardous waste companies in BC, rather than allowing wastewater to be discharged directly into a river or the ocean. However, efforts to clean up and remove PCBs from water in BC are minimal. There is water quality testing in place, but actual cleanup seems more prevalent on the East Coast of Canada. 

Wastewater is only one factor that contributes to the entry of PCBs into the water. Wastewater is tested for PCB, but filtering the wastewater does not have a significant enough impact. High concentrations of PCBs present in the soil for such a long period still have a significant impact on oceanic PCB levels.  

 

Long-term research and monitoring: 

• There are multiple impacts on the decline in the SRKW population. To ensure conservation efforts are effective, long-term monitoring would be required. Long-term research and monitoring of Chinook salmon, water quality, and pollutant levels would contribute to the overall health of the ecosystem and the SRKW. Long-term studies would highlight areas of high concern and urgent measures, while also demonstrating the effectiveness of conservation measures implemented. Research and monitoring can include water quality testing, spatial monitoring, visible and acoustic surveying, managing chinook salmon fisheries, and policy implementation. 

 

Conclusion

 

Research to date has shown the impacts on the SRKW, and that action needs to be taken. If conservation efforts are not enforced, the future looks bleak for the population, and it is predicted to be declared extinct within the next 40 years. Orcas were voted as the representative species for British Columbia in 2025, making it even more important that the government of Canada, industrial companies, and water users act. 

 

We have seen species, including the humpback whale population in BC, make a comeback with conservation efforts put in place. The potential recommendations made here are summarized; further recommendations are outlined in the report from the conservation organization, which calls for the Canadian government to act urgently. 

 

References: 

A world first: Plan to save B.C.'s southern resident orcas announced | Vancouver Sun

Strengthening recovery actions for Southern Resident killer whales | Raincoast

What are PCBs?

Largely banned industrial chemicals could wipe out killer whales, study warns