Scaleshell Mussel

Scaleshell Mussel

USFWS Photo

The scaleshell is a freshwater mussel that was listed an endangered species in 2001 by the U.S. Fish & Wildlife Service. The scaleshell mussel is a relatively small freshwater mussel with a thin, fragile shell and faint green rays. It grows to about one to four inches in length. The inside of the shell is pinkish white or light purple and highly iridescent. The scaleshell gets its name from the scaly appearance of the shell, which is only seen in females.

Habitat Loss and Endangerment
Scaleshells live in medium- sized and large rivers with stable channels and good water quality. They bury themselves in the sand and gravel on the bottom with only the edge of their partially opened shells exposed. Scaleshells are endangered by a number of factors. Mussels are highly susceptible to pollution because of their sedentary nature. Their habitat can be degraded by changes in sedimentation, temperature, flow patterns and fish migration, all of which are now influenced by dams and changes in land use.

A New Invasive Threatens
The exotic Zebra Mussel, though not currently invading the Recreational River, is a serious threat to many native shellfish, starving and suffocating them by attaching to their shells in large numbers. The survival of the scaleshell on the Missouri River depends greatly on the restoration of habitat and improved surface land management