Beavers wash up dead along Salish Sea shores

Dead beavers found along Salish Sea shores

Marine researchers are puzzled by the discovery of dead beavers along the Salish Sea in San Juan County. Fox 13's Franque Thompson reports on the efforts of experts from The Whale Museum to uncover the cause, urging the public to report sightings to aid in solving this environmental mystery.

FRIDAY HARBOR, Wash. - Researchers need the public’s help solving a mystery in San Juan County. Beavers are showing up dead along the shores of the Salish Sea. It’s an unusual sighting for the creatures that are so vital to Washington’s marine environment.

What they're saying:

"Beavers are critical to the environment here and in the climate resiliency, especially in these tidal areas like the estuaries along the Salish Sea," said Erin Casellas, field operations coordinator for The Whale Museum. "The Chinook Salmon smolt depend on the habitats that the beavers create. They’re building their dams, and in turn these Chinook salmon are what many other species, like the endangered Southern Resident killer whales are also depending on."

Experts with the museum, located in Friday Harbor, are currently waiting for test results on what killed the beavers. Researchers said their team isn’t sure if the creatures died from toxins, disease, human influence, or climate-related stress.

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Casellas said, whatever it is, they’re hoping to learn answers soon to take preventative measures to better protect them and the entire Salish Sea.

"A lot of us think of them as just freshwater rodents that are hanging out and building dams and creating these awesome wetland habitats. But they are really critical parts of the marine environment," said Casellas.

The San Juan County Marine Mammal Stranding Network is a program of the museum in collaboration with Seadoc Society. Casellas said the network doesn’t usually focus on beavers. However, in October 2024, the health and safety of the creatures got the network’s attention.

"A very large, about 60-pound male was found on a beach on Orcas Island. Seadoc Society got that report, and they collected the beaver and froze it," said Casellas.

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Marine researchers with The Whale Museum analyze dead beavers along the shores of the Salish Sea. (The Whale Museum)

In March, the researchers received three calls for dead beavers found on San Juan beaches.

"In three weeks, we picked up three different ones. None of them presented any significant external lesions. So, from the outside we didn’t see any big cuts or scratches on them," said Casellas.

According to one comment on the network’s Facebook post, a person wrote they saw a dead beaver in a freshwater wetland in Snohomish County.

What's next:

Unsure what was killing the beavers, Casellas said their team of experts sent frozen tissue samples on Wednesday to the Washington Animal Disease Diagnostics Laboratory for answers.

"This testing is so important," said Casellas. "By testing different tissues from test beavers, we’re able to see if it’s bacteria, a virus, a fungal infection, something else. And then from there we know who we need to involve to hopefully prevent this from happening more."

While their team waits for the test results of the mysterious deaths, Casellas said the researchers are also asking the public for help. She said this can be done by staying a safe distance away from the dead animal and filing an online report to the Washington State Department of Fish and Wildlife.

"If people are finding dead beavers in other areas, we want to know these reports. The more dead animals that we can respond to and test, hopefully the more answers we can find," said Casellas.

To learn more about beavers along the Salish Sea, the San Juan County Marine Mammal Stranding Network is posting educational segments on its Facebook page this week.

The Source: Information in this story is from the San Juan County Marine Mammal Stranding Network, The Whale Museum and FOX 13 Seattle reporting.