Quantcast

Car Pollution Is Killing Coho Salmon

Animals

The grisly video above shows a coho salmon struggling to survive in polluted stormwater runoff on the Duwamish River in Washington. This contaminated water—filled with oil from cars, pesticides, dirt and debris—can kill this particular species of Pacific salmon in hours, according to Puget Soundkeeper Alliance, which posted the clip on Oct. 21.

Sadly, it appears that this fish is one of many coho salmon in the Puget Sound Basin that have died, and will continue to die, from this man-made tragedy.


A new study, published in the Ecological Society of America's journal Ecological Applications, has found "that contaminants in stormwater runoff from the regional transportation grid likely caused these mortality events."

"Further, it will be difficult, if not impossible, to reverse historical coho declines without addressing the toxic pollution dimension of freshwater habitats," the authors note.

Stormwater runoff comes from rain that falls on streets, parking areas and other developed land and flows directly into waterways. As it flows, the water can collect a potentially toxic cocktail of oil, grease, animal waste, litter, pesticides, fertilizers and other potential pollutants.

The new analysis was compiled by researchers at National Oceanic and Atmospheric Administration's (NOAA) Northwest Fisheries Science Center in Seattle along with collaborators at the U.S. Fish and Wildlife Service, local tribes and the Wild Fish Conservancy.

For the study, researchers surveyed coho mortality rates at 51 spawning sites in Puget Sound and were able to positively link die-offs to increased road density and traffic intensity, among other variables.

Citing the study, the Herald Net wrote, "The results show that in an estimated 40 percent of their range in the Puget Sound Basin, 10 to 40 percent of coho salmon die before they can even spawn because of pollution."

Earlier experiments have also found that coho salmon swimming in untreated stormwater experienced 100 percent mortality, while coho swimming in stormwater filtered by soil, bark chips and gravel survived.

The team was able to generate a predictive mortality risk map for the entire Puget Sound Basin.

"It can be extremely useful for urban planning to know that if you develop this area and in an old-school way you are going to take out a lot of coho," Blake Feist, lead author on the paper, told The Seattle Times.

"We have to act now," said Jay Davis, an environmental toxicologist for the U.S. Fish and Wildlife Service who coordinated field research for the study. Davis told the Washington Post that the coho population could crash in as little as six years.

Incidentally, coho is the only one out of the five salmon species—chinook, sockeye, pink and chum—that is experiencing this rate of mortality, a "great mystery that we are working on," Nat Scholz, NOAA research zoologist, told the Washington Post.

The solution could lie in "green infrastructure and similar clean water strategies could prove most useful for promoting species conservation and recovery," the authors note.

Puget Soundkeeper Alliance also suggested that "smarter development of land and on-site filtering of stormwater, which helps control both pollution and flooding."

As it happens, four species of coho salmon are protected under the Endangered Species Act throughout the West Coast, including the Lower Columbia River (threatened), Oregon Coast (threatened), Southern Oregon and Northern California Coasts (threatened), and Central California Coast (endangered).

Elsewhere, the Central California Coast coho salmon—once plentiful in local rivers and streams—is now "living on the edge" as it faces challenges such as multiyear droughts and the increased presence of fine sediment, rocks and fallen trees from damming and logging activities, according to the Santa Cruz Sentinel.

And as Mongabay reports, northwest salmon fisheries have been struggling due to warming oceans and overdeveloped, dammed and silted spawning rivers and streams. While federally funded local, state and tribal programs administered by NOAA have helped declining salmon fisheries, President Trump's 2018 budget would cut all those programs. For now, Congress has restored them.

You can learn more about the threat of toxic runoff and how you can help here.

EcoWatch Daily Newsletter

Example of starlings murmuration pictured in Scotland. Tanya Hart / Flickr / CC BY-SA 2.0

Police in Wales are in the midst of an unusual investigation: the sudden death of more than 200 starlings.

Read More Show Less
Donald Trump Jr. killed an argali sheep like this one on a hunting trip in Mongolia. powerofforever/ iStock / Getty Images Plus

During a hunting trip in Mongolia this August, Donald Trump Jr. shot and killed an endangered argali sheep, and received a permit only after the fact.

Read More Show Less
Sponsored
In this view from an airplane rivers of meltwater carve into the Greenland ice sheet near Sermeq Avangnardleq glacier on Aug. 4 near Ilulissat, Greenland. Climate change is having a profound effect in Greenland, where over the last several decades summers have become longer and the rate that glaciers and the Greenland ice cap are retreating has accelerated. Sean Gallup / Getty Images

The rate that Greenland's ice sheet is melting surpassed scientists' expectations and has raised concerns that their worst-case scenario predictions are coming true, Business Insider reported.

Read More Show Less
An Alagoas curassow in captivity. Luís Fábio Silveira / Agência Alagoas / Mongabay

By Pedro Biondi

Extinct in its habitat for at least three decades, the Alagoas curassow (Pauxi mitu) is now back in the jungle and facing a test of survival, thanks to the joint efforts of more than a dozen institutions to pull this pheasant-like bird back from the brink.

Read More Show Less
Elizabeth Warren's Blue New Deal aims to expand offshore renewable energy projects, like the Block Island Wind Farm in Rhode Island. Luke H. Gordon / Flickr

By Julia Conley

Sen. Elizabeth Warren expanded her vision for combating the climate crisis on Tuesday with the release of her Blue New Deal — a new component of the Green New Deal focusing on protecting and restoring the world's oceans after decades of pollution and industry-caused warming.

Read More Show Less