It’s the water, or maybe it’s just the nasty stuff that’s in the water.
A new series of studies by federal researchers is delving into the question of which pollutants in urban streams are killing coho salmon.
Photo by Tiffany Royal, Northwest Indian Fisheries Commission
As I describe in a story in today’s Kitsap Sun, the new studies involve coho returning to the Suquamish Tribe’s Grovers Creek Hatchery in North Kitsap.
Of course, pollutants in streams are just one factor affecting salmon in the Puget Sound region, where development continues to alter streamflows and reduce vegetation, despite efforts to protect and restore habitat. But pollution may play a role that has gone largely unnoticed in some streams.
The new studies continue an investigation that began more than a decade ago with the involvement of numerous agencies. By now, most of us have heard about the effects of copper on salmon, but the latest round of studies will look at the collection of pollutants found in stormwater to see how they work together. It may be possible to pinpoint the chemical concentrations that result in critical physiological changes in salmon.
The latest work involves a team led by David Baldwin of NOAA Fisheries and Steve Damm of the U.S. Fish and Wildlife Service. The Suquamish Tribe is providing the fish, along with facilities and support.
For information on the ongoing effort to understand how toxic chemicals affect salmon, review these pages on the website of the Northwest Fisheries Science Center:
Acute die-offs of adult coho salmon returning to spawn in restored urban streams
The impacts of dissolved copper on olfactory function in juvenile coho salmon
Mechanosensory impacts of non-point source pollutants in fish
Cardiovascular defects in fish embryos exposed to polycyclic aromatic hydrocarbons
A page called “Coho Pre-spawn Mortality in Urban Streams” presents a series of videos that show the advance of an apparent neurological disease that first causes disorientation in coho salmon and then death. The video is taken in Seattle’s Longfellow Creek, an urban stream.
