The U.S. Fish and Wildlife Service is recommending that we unplug the machines and turn out the lights on three species of mussels. They’ve been on the endangered species list for decades, but survey after survey has turned up nary an individual. They include the delightfully named turgid-blossom pearlymussel, yellow-blossom pearlymussel, and green-blossom pearlymussel, all of which were once found in the Tennessee and Cumberland river drainages.

From their press release:

“Biologists have conducted comprehensive mussel surveys in rivers historically supporting these species, but have not found them despite the fact that some of the rivers currently support good populations of other mussel species. While not targeted for these blossom mussels, these surveys were thorough, and have been conducted throughout the past several decades…

Habitat fragmentation, alteration, and destruction are the leading probable causes for the three mussel species’ decline.”

In April, I reported on Kentucky’s endangered mussels. They’re great at filtering river water. But that talent also makes them vulnerable to pollution. Biologists consider them a “sentinel species,” some of the first to show signs of trouble in a river.