Public asked to help track sick salmon

October 10, 2018

Scientists know that as water runs off roads and other hard surfaces into streams, it can become polluted and be toxic to salmon.

Now, a team of scientists is working to understand the extent of the problem in the Puget Sound region.

The scientists are studying where and how that water, called stormwater runoff, sickens and kills salmon in area streams, and a new website allows the public to report sightings of sick and dead salmon.

“Residents of the Puget Sound region can provide important data to help us document affected watersheds,” U.S. Fish & Wildlife Service environmental toxicologist Jay Davis said in a news release. “There are potentially thousands of toxic chemicals in stormwater runoff, and refining our understanding of where and when this phenomenon is occurring can help us narrow our focus and provide an important part to this puzzle.”

When salmon are exposed to toxic stormwater runoff, they can die within hours.

“Runoff contains a soup of heavy metals and hydrocarbons that are highly toxic to fish,” Washington State University researcher Jen McIntyre said in the release.

Scientists from the National Oceanic and Atmospheric Administration, Fish and Wildlife Service and WSU have worked for years together as the Puget Sound Stormwater Science Team to study the effects of stormwater runoff on salmon.

The team is now working to determine which chemicals are toxic to salmon and where the fish are being affected.

So far, coho salmon appear to be the most vulnerable, according to the release. Before dying, affected coho and other salmon species may show signs of being sick, such as unusual movements or not moving at all, according to the website.

The stormwater team is calling that phenomenon urban runoff mortality syndrome and is asking the public to help track the syndrome.

On a new website, the public can learn how to identify coho and submit observations.

Fish & Wildlife Service spokeswoman Ann Froshauer said Skagit County is of particular interest because the stormwater team has not done surveys in the area.

“We really need the additional ‘boots on the ground’ of area residents to help identify watersheds for further study,” she said.

Under a “Report Coho Mortality” tab on the website, community members are asked to include details such as salmon species, sex, length, and location and date it was seen.

Based on the team’s research, 10 to 40 percent of coho in much of the Skagit River and the lower watershed are expected to die of the syndrome.

As urban growth and development continue in the region, scientists expect more salmon to die of the syndrome, according to the release. That could have significant impacts on wild coho populations, some of which are listed as threatened under the Endangered Species Act.

Those fish are also an increasingly important food source for the endangered Southern Resident orca population, which recently reached its lowest number of whales in 30 years.

“Every coho that dies in our polluted urban watersheds before it gets a chance to spawn means less eggs, fewer fry, and fewer returning fish to feed hungry orcas,” McIntyre said.

Nat Scholz, an ecotoxicologist with NOAA’s Northwest Fisheries Science Center in Seattle, said that is why it’s important for researchers to learn where salmon are being affected.

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