Pacific Northwest freshwater mussels are now ‘crying’ for help

Northwest freshwater mussels are in trouble, declining rapidly in nearly every study by population biologists.

Take 2005, when biologists counted the historic number of freshwater mussels in the North Fork of Oregon’s John Day River. They counted about 500 mussels per square meter, which is similar to what Lewis and Clark noted on their westward expedition.

A western ridged mussel in Washington’s Chehalis River.

“They said you couldn’t enter the river without stepping on 100 mussels,” said Alexa Maine, lead biologist for the Confederate Tribes Indian Reservation Freshwater Mussel Research and Restoration Project. Umatilla.

By 2007, all mussels in the North Fork of the John Day River were gone, Maine said.

“When the mussels start dying off en masse like we’re seeing now, that, to me, signals there’s a bigger problem that we don’t yet recognize,” Maine said.

Biologists don’t know what’s going on. They work to figure it out quickly.

Freshwater mussels face challenges such as warming waters caused by climate change, an abundance of non-native fish species, habitat destruction and pollution.

In fact, the US Fish and Wildlife Service is taking a closer look at one species of freshwater mussel, the western ridged mussel.

The service first conducted a 90 day initial assessment who have found western ridged mussels might be a good candidate for the endangered species list.

Now, the service will conduct an even more thorough inspection, known as a species status assessment, of the western ridged mussel in all five of its range states, including Oregon, Washington State and Idaho.

The assessment will help researchers learn more about the life history and current conditions of the Western Ridged Mussel. Additionally, the assessment will predict what the future of the Western Striped Mussel might look like.

Only a handful of freshwater mussels can be found in the West, compared to the roughly 300 species found east of the Continental Divide, Maine said.

“It’s pretty hard these days to find two species in the same place together, let alone a population that we call self-sustaining,” said Maine’s Western Mussels.

Christine O'Brien (foreground) and Alexa Maine (background) of the Confederate Tribes of the Umatilla Indian Reservation pull each other over rocks while diving into the shallow waters of the John Day River in the eastern Oregon in July 2021.

Christine O’Brien (foreground) and Alexa Maine (background) of the Confederate Tribes of the Umatilla Indian Reservation pull each other over rocks while diving into the shallow waters of the John Day River in the eastern Oregon in July 2021.

Freshwater mussels, which live for 60 to 100 years, clean up the rivers and streams where they are found. One mussel can clean up 10 gallons of water in about 30 minutes, said Courtney Newlon, a fish and wildlife biologist with the US Fish and Wildlife Service.

“Mussels do a lot of behind-the-scenes work like maintaining water quality, filtering out sediment like pollutants and bacteria, and they provide food and habitat for other aquatic species,” Newlon said. .

A time lapse video of freshwater mussels filtering water.

As the species on which these ecosystems depend, known as a keystone species, freshwater mussels could be an indicator that all is not well in northwest waters, Maine said.

“I think mussels are part of this bigger picture of environmental decline and destruction of species and everything that’s going on,” she said.

Additionally, tribes used mussel shells as a cultural resource in jewelry and ornamentation, Maine said. Historically, tribes viewed freshwater mussels as a first fooda staple food source, boil and dry them to eat in the winter, Maine said.

The Confederated Tribes of the Umatilla Indian Reservation run the only project dedicated to raising and restoring freshwater mussels in the West.

For this project, Maine is snorkeling in the rivers of land ceded to the tribe, scouring the riverbeds in search of what might at first appear to be a rock, but is instead a mussel. pure water.

After finding many mussels that didn’t reproduce, she said she wondered if she was watching older mussels die off over decades.

“The mussels are now screaming, ‘Help us do something, something’s happening,'” Maine said.

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