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August 13, 1999
Wally Jobman (NE) 308-382-6468,x16
Nell McPhillips (SD) 605-224-8693, x32 (Available 8/16)
Sharon Rose (CO) 303-236-7917,x 415
Georgia Parham 812-334-4261 x 203
Andy Roberts 573-876-1911 x 110

U.S. Fish and Wildlife Service Proposes Endangered Status for Scaleshell Mussel

The U.S. Fish and Wildlife Service today proposed to list the scaleshell mussel, a freshwater species once found in many rivers in the eastern United States, as endangered under the Endangered Species Act. A plant or animal is designated as endangered if it is in danger of extinction throughout all or a significant portion of its range.

Nearly 75 percent of historically known river populations of scaleshells have disappeared, said Bill Hartwig, the Service’s regional director for the Great Lakes-Big Rivers region. The species once inhabited 53 rivers or streams throughout most of the eastern United States, with populations found as far west as Oklahoma, but now is found only in 13 rivers.

"The decline of the scaleshell is an all-too-common trend in freshwater mussels in the United States," Hartwig said. "Freshwater mussels are valuable members of aquatic ecosystems, and act as excellent indicators of the quality of the water they inhabit – water we all depend upon. Unfortunately, mussels are one of the most endangered groups of animals in the country."

The scaleshell is a relatively small freshwater mussel species measuring 1 to 4 inches in width with a thin, fragile shell and faint green rays. This species inhabits medium-sized and large rivers with stable channels and good water quality.

Scaleshells currently exist in Missouri (Meramec River, Big River, Bourbeuse River, Gasconade River and possibly Big Piney River); Arkansas (St. Francis River, Spring River, South Fork Spring River, Strawberry River, South Fourche LaFave River, Cossatot River, Saline River, and Little Missouri River); and Oklahoma (Kiamichi River). Of these populations, 10 are thought to be declining. The status of the scaleshell in the Missouri River in South Dakota is unknown.

Threats to the scaleshell, as with many other mussel species, include degraded water quality due to pollution and sedimentation, alteration of habitat through damming of waterways, dredging and channelization of rivers, and competition with non-native species like the zebra mussel. In particular, pollutants from industrial sources, sewage, and spills can kill mussels, and sedimentation from dredging and erosion along rivers and streams can cover them and impair respiration and feeding. Mussels are sedentary animals and cannot move away from threats.

The scaleshell’s range overlaps those of several other mussel species that are already federally listed as endangered or threatened. They include the pink mucket in the Meramec, Big, Gasconade, Spring, Strawberry, and Little Missouri rivers; the fat pocketbook in the St. Francis River; the Curtis pearly mussel in the South Fork Spring River; the Ouachita rock-pocketbook in the Kiamichi River; the Arkansas fatmucket in the Saline River; and the winged mapleleaf in the Little Missouri.

Because the primary threat to the scaleshell -- degradation of water quality due to non-point source pollution -- is the same as that for listed mussels, steps needed to conserve the scaleshell would be similar to measures already in place for other mussels in its range. In general, recovery actions focus on best management practices and existing technology to control pollutants and sedimentation and minimize their impacts on mussels. As a result, the Service does not expect that a decision to list the scaleshell would have any significant additional impact on activities on the rivers.

The Service’s action initiates a thorough review of the scaleshell during which the agency will determine whether endangered status is appropriate. Public comment will be sought on the proposal, and the Service will make a final determination in one year.

If the Service determines that endangered status is appropriate for the scaleshell, the species will benefit from protections and recovery actions under the Endangered Species Act. Species listed as endangered are protected from direct and indirect "take," which includes killing, harming, or harassing. Federal agencies must consult with the Service to ensure that any action they authorize, fund, or carry out does not jeopardize the continued existence of the species. In addition, the Service would assemble a recovery team to identify and implement actions to restore populations so that extinction is no longer a threat.

The Service published the proposal to list the scaleshell in today’s Federal Register. The public may comment in writing until October 13, 1999. Comments may be directed to U.S. Fish and Wildlife Service, Columbia Field Office, 608 East Cherry Street, Room 200, Columbia, Missouri.

For further information about the programs and activities of the U.S. Fish and Wildlife Service in the Great Lakes-Big Rivers Region, please visit our HomePage at:

The U.S. Fish and Wildlife Service is the principal Federal agency responsible for conserving, protecting, and enhancing fish, wildlife and plants and their habitats for the continuing benefit of the American people. The Service manages the 93-million-acre National Wildlife Refuge System comprised of more than 500 national wildlife refuges, thousands of small wetlands, and other special management areas. It also operates 66 national fish hatcheries, 64 fish and wildlife management assistance offices and 78 ecological services field stations. The agency enforces Federal wildlife laws, administers the Endangered Species Act, manages migratory bird populations, restores nationally significant fisheries, conserves and restores wildlife habitat such as wetlands, and helps foreign governments with their conservation efforts. It also oversees the Federal Aid program that distributes hundreds of millions of dollars in excise taxes on fishing and hunting equipment to state wildlife agencies.

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