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Taking Action Against Pollution: Killer Whale Populations in the Salish Sea

The Georgia Strait Alliance is a Canadian-based organization dedicated to protecting the Salish Sea, which sits just off the coast of Washington and British Columbia. They are committed to finding solutions to various threats facing the sea, including pollution and biodiversity loss. One of their goals revolves around removing contaminants from the water and protecting the organisms that inhabit it. In recent years, the organization’s efforts have turned specifically towards the conservation of killer whales and their main food source, Chinook salmon.

The orcas in the Salish Sea are both ecologically important and culturally significant to the Indigenous people of the area. This population of orcas was declared endangered in 2003 by the federal government. Funding was set aside in 2018 (the Whales Initiative) for research into what was harming the orcas, as well as how the effects could be mitigated. According to Shinjini Pilon, an environmental scientist with Environment and Climate Change Canada, the biggest threats to these orcas are all anthropogenic in nature: contaminants, a lack of suitable prey, and acoustic and physical disturbances from marine vessels.

The presence of toxins in the Salish Sea is one of the most pressing of these concerns. Pollutants wind up accumulating at the highest trophic level via the process of biomagnification, where contaminants enter the food web through lower-level organisms and increase in concentration with every jump in trophic level. There are persistent pollutants present in these orcas that were banned by the government years ago, and the orcas have also been documented with the highest levels of PCBs (Polychlorinated biphenyls; man made chemicals) ever recorded in any animal. These pollutants enter the water from a number of sources, including wastewater treatment plants, pulp and paper plants, landfill leachate, and agricultural runoff, among others. When orcas hunt and consume salmon, they ingest the pollutants, and then pass them along to their offspring through nursing, which ultimately increases the vulnerability of the population as a whole.

Limiting the pollution of these contaminants is difficult, especially when very little data exists on the effects they have on predators like killer whales. Research is currently underway to fill in those data gaps where possible in order to create environmental quality guidelines that will serve to reduce water contamination. Guidelines are voluntary, as they are not hard laws with government-backed repercussions. However, they bring an awareness to the public of the issue at hand and can prove effective when a sizable portion of the community chooses to abide by them. Kathleen Mctavish, an environmental quality analyst with Environment and Climate Change Canada, is spearheading research into what are acceptable concentrations of these contaminants in the soil, water, prey base, and orcas themselves. Ethical considerations must be made in regards to how they can study the orcas, because tissue samples are not readily available. She notes that there are already guidelines for some known pollutants, but not all. What’s more, these guidelines were intended to protect prey animals rather than predators, owing again to a lack of data. Creating guidelines for these other pollutants is crucial to protecting the Salish Sea orcas, though they are not the only means of doing so.


Biomagnification. Energy Education. (n.d.).

Canada, E. and C. C. (2021, April 28). Government of Canada.

Georgia Strait Alliance. (2021, April 27).

Government of Canada, E. and C. C. C. (2016, June 1). Federal Environmental Quality Guidelines Vanadium. Environment and Climate Change Canada .

Orca Salmon Alliance. (n.d.). Orca Action Month.

Pilon, S., McTavish, K. (2021, May 12). Southern Resident Orcas: Combatting Contaminants for Healthy Habitats [Webinar]. In Georgia Strait Alliance Webinar Series. Retrieved from s-tickets-152158234375?keep_tld=1#.

Transport Canada. (2020, September 18). Whales Initiative: Protecting the Southern Resident Killer Whale. Transport Canada.

1 Comment

Unknown member
Nov 11, 2022

Thanks for this article. Nature must be treated with care. This applies to all types of activities. After the rest, it is necessary to remove the garbage. And also do not forget the things that you take with you, for example alpicool portable refrigerator. This is right and helps to save the environment.

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