New StoryMap Explores the Link Between Pollution and Orcas in Commencement Bay
For more than 30 years, Communities for a Healthy Bay’s (CHB) Bay Patrol has documented pollution across Commencement Bay. Now, for the first time, those community-driven observations have been paired with orca sighting data from The Orca Network to ask an important question: how does pollution affect the way orcas use our waters?
Using ArcGIS mapping and statistical analysis, CHB’s Marine Science Field Technician, Audrey Holloway, examined data from 2020–2024, comparing pollution reports with orca sightings. The results were clear: in areas where pollution was reported more often, orcas were seen less frequently. Even more concerning, sightings of orca calves—both residents and transients—were rare in polluted areas.
While correlation does not mean causation, the findings suggest that orcas may be avoiding parts of the Bay where pollution is concentrated, altering how and when they use the habitat.
Why This Matters
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Citizen science works. Opportunistic data collection—like community reports and Bay Patrol logs—is non-invasive, cost-effective, and accessible to anyone with a passion for marine conservation.
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Pollution impacts wildlife. The analysis found a moderately strong negative correlation between pollution presence and orca sightings. As pollution increased, orca presence decreased.
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Community-driven research matters. This project shows how local involvement can help advance scientific understanding and inform conservation action.
What This Means for Our Community
The findings underscore the importance of reducing pollution in Commencement Bay and across the South Sound. If orcas are actively avoiding polluted waters, then the health of our marine ecosystem and the survival of these charismatic species are directly tied to our actions on land and water. For the public, the takeaway is clear: preventing pollution benefits not only people and our waterways but also ensures that orcas continue to visit, feed, and raise their young in our region. Every community action to curb pollution, from supporting stronger environmental protections to preventing litter and runoff, helps keep Commencement Bay a place where orcas can thrive.
Explore the StoryMap
To make this research accessible to everyone, an interactive StoryMap that combines history, maps, and analysis into a clear narrative was created. Whether you’re a scientist, educator, or community member, the StoryMap offers an engaging way to explore the Bay and learn about the connections between pollution and orca survival.