FWS proposes listing of, and critical habitat for, Georgia Pigtoe Mussel, Interrupted Rocksnail, and Rough Hornsnail
74 Fed. Reg. 31114 / Vol. 74, No. 123 / Monday, June 29, 2009 / Proposed Rules
DEPARTMENT OF THE INTERIOR / Fish and Wildlife Service / 50 CFR Part 17 / Endangered and Threatened Wildlife and Plants; Proposed Endangered Status for the Georgia Pigtoe Mussel, Interrupted Rocksnail, and Rough Hornsnail with Critical Habitat
SUMMARY: We, the U.S. Fish and Wildlife Service (Service), propose to list the Georgia pigtoe mussel (Pleurobema hanleyianum), interrupted rocksnail (Leptoxis foremani), and rough hornsnail (Pleurocera foremani), as endangered species under the Endangered Species Act of 1973, as amended (Act). The Georgia pigtoe, interrupted rocksnail, and rough hornsnail are endemic to the Coosa River drainage within the Mobile River Basin of Alabama, Tennessee, and Georgia. These three species have disappeared from large portions of their natural ranges due to extensive construction of dams that eliminated or reduced water currents and caused changes in habitat and water quality. The surviving populations are small, localized, and highly vulnerable to water quality and habitat deterioration. We are also proposing to designate critical habitat concurrently for the Georgia pigtoe, interrupted rocksnail, and rough hornsnail under the Act. In total, approximately 258 kilometers (km) (160 miles (mi)) of stream and river channels fall within the boundaries of the proposed critical habitat designation for the three species: 153 km (95 mi) for the Georgia pigtoe, 101 km (63 mi) for the interrupted rocksnail, and 27.4 km (17 mi) for the rough hornsnail. The proposed critical habitat is located in Cherokee, Clay, Coosa, Elmore, and Shelby Counties, Alabama; Gordon, Floyd, Murray, and Whitfield Counties, Georgia; and Bradley and Polk Counties, Tennessee. These proposals, if made final, would implement Federal protection provided by the Act. DATES: We will accept comments received on or before August 28, 2009.
The Georgia pigtoe, interrupted rocksnail, and rough hornsnail are riverine-adapted species that depend upon adequate water flow and are not found in ponds or lakes. See Outdoor Alabama about ecological importance of the interrupted rocksnail, and Alabama State Park information about reintroduction efforts. Continuously flowing water is a habitat feature associated with all surviving populations of the three species. Flowing water maintains the stream bottom and shoal habitats where these species are found, transports food items to the sedentary juvenile and adult life stages of the Georgia pigtoe, supports the periphyton and biofilm ingested by the interrupted rocksnail and rough hornsnail, removes wastes, and provides oxygen for respiration for each of the three species. Graphic image available from Outdoor Alabama.