Coho Salmon Mortality in Urban Streams
Author Information
Author(s): Blake E. Feist, Eric R. Buhle, Paul Arnold, Jay W. Davis, Nathaniel L. Scholz
Primary Institution: Northwest Fisheries Science Center, National Marine Fisheries Service, NOAA
Hypothesis
Are toxic chemical contaminants in urban runoff causing high mortality rates in coho salmon spawners?
Conclusion
The study found that coho salmon spawner mortality is closely linked to urban land use, particularly the presence of impervious surfaces and local roads.
Supporting Evidence
- High mortality rates of coho salmon spawners were observed in urban streams, ranging from 25% to 90%.
- Mortality was positively correlated with the proportion of local roads and impervious surfaces in the drainage basins.
- The study identified unmonitored basins at risk for coho mortality based on land use characteristics.
Takeaway
Coho salmon are dying in urban streams because of pollution from roads and buildings, which makes the water toxic for them.
Methodology
The study used spatial analyses to correlate land use and land cover with coho salmon mortality across six urban streams.
Potential Biases
Potential bias due to the focus on urban streams where coho mortality was observed, possibly overlooking other factors.
Limitations
The study did not evaluate hydrologic or geomorphic basin characteristics, which may also influence salmon mortality.
Participant Demographics
The study focused on adult coho salmon returning to spawn in urban streams in the Puget Sound region.
Digital Object Identifier (DOI)
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