PORTLAND, Ore.— The Center for Biological Diversity today notified the U.S. Fish and Wildlife Service it intends to sue the agency for failing to make a timely decision on whether the western ridged mussel should be protected under the Endangered Species Act. These important, imperiled mussels are disappearing from streams and rivers across the three West Coast states and Idaho and Nevada.

Freshwater mussels play a critical role in keeping rivers healthy by naturally filtering water. A single mussel can filter gallons each day, removing algae, bacteria and other particles and helping keep rivers clean for fish, wildlife and people.

“Western ridged mussels quietly do enormous work keeping our rivers clean but they’re disappearing from many rivers in an unfolding extinction crisis,” said Meg Townsend, a freshwater attorney at the Center. “These remarkable animals can sometimes live for more than half a century, but they’re on the brink of extinction and need Endangered Species Act protection soon if they’re going to survive.”

Despite their importance, freshwater mussels are among the most imperiled animals in North America. Western ridged mussels have declined across much of their range because of dams, water pollution, habitat loss, drought and invasive species.

The Endangered Species Act requires the Service to make timely decisions on petitions to list species as endangered or threatened, ensuring that species facing extinction receive prompt protection. But despite mounting threats from dams, pollution, drought and invasive species, the agency has missed its deadline to determine whether the western ridged mussel warrants protection.

The Center’s notice of intent to sue gives the agency 60 days to comply with the law. If it fails to act, the Center intends to file suit in federal court to compel a decision.

“Protecting the western ridged mussel will help protect entire river systems that people, fish and wildlife rely on,” said Townsend. “Freshwater mussels are living indicators of river health. When they disappear, it’s often a sign that whole ecosystems are in trouble.”

Background

The western ridged mussel is native to rivers and streams throughout the western United States, including the Columbia and Snake river basins. Adult mussels spend most of their lives partially buried in river sediments and move only short distances.

Individual western ridged mussels can live for decades, sometimes up to 60 years, filtering water and helping maintain water quality for fish, wildlife and people.

Like many freshwater mussels, western ridged mussels rely on native fish to reproduce. Their larvae, known as glochidia, must temporarily attach to the gills or fins of native fish to develop before dropping to the riverbed and growing into adult mussels.

This dependence on host fish makes western ridged mussels especially vulnerable to dams, habitat fragmentation and declining water quality. Dams that block fish migration and other disruptions to river ecosystems can threaten the mussel’s survival.

Western ridged mussels have declined across much of their historic range because of river damming, degraded water quality, climate-driven drought and invasive species such as zebra and quagga mussels. Losing western ridged mussels and the water filtration and nutrient cycling functions they provide can have cascading impacts that harm entire river ecosystems.