Slabside Pearlymussel: Freshwater Species of the Week

Slabside pearlymussel


America’s mussels may have gotten stronger this week. On October 3, the U.S. Fish and Wildlife Service proposed Endangered Species Act protection for two species of freshwater mussels in the Tennessee River watershed, including proposed designation of 1,380 miles of critical river habitat in Alabama, Kentucky, Mississippi, Tennessee, and Virginia.

freshwater species of the weekThe mussels are the slabside pearlymussel (Pleuronaia (=Lexingtonia) dolabelloides) and fluted kidneyshell (Ptychobranchus subtentum).

The slabside was once also found in Kentucky but now survives in only 11 streams in Alabama, Mississippi, Tennessee, and Virginia, according to the Center for Biological Diversity.

The fluted kidneyshell is now gone from Alabama, and it lives in only 12 of the 37 streams where it was originally found, distributed in Kentucky, Tennessee, and Virginia.

Both mussels are threatened by dams, gravel mining, and pollution.

“Saving these mussels will take a shoulder-to-the-wheel effort,” Tierra Curry, a conservation biologist with the Center for Biological Diversity, said in a statement. “But with the Endangered Species Act being 99 percent effective at preventing the extinction of species under its care, we’re hopeful these Tennessee River natives won’t be erased.”

The slabside pearlymussel has a shiny, greenish-yellow, triangular shell that is white on the inside. It is usually around four inches long. The fluted kidneyshell is about five inches long and has a yellowish-brown oval shell with wide green rays. The inside of its shell is bluish-white, with a streak of salmon pink.

We’ve written before about freshwater mussels, which are particularly vulnerable around the world. They have long been important food sources for wildlife and people, and their shells have been used by other living things, including by humans for buttons, ornaments, and much more. They also function like vacuum cleaners that filter materials, including some toxins, out of the stream.

But freshwater mussels need clean water and relatively uninterrupted flows. That’s why scientists often consider them indicator species of ecosystem health.


Brian Clark Howard covers the environment for National Geographic. He previously served as an editor for and E/The Environmental Magazine, and has written for Popular Science,,,, Yahoo!, MSN, and elsewhere. He is the co-author of six books, including Geothermal HVACGreen LightingBuild Your Own Small Wind Power System, and Rock Your Ugly Christmas Sweater.