Vol. 69, No. 168, United States Fish and Wildlife Service (FWS), 50 CFR Part 17, RIN 1018-AI76, 69 FR 53136
Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for Five Endangered Mussels in the Tennessee and Cumberland River Basins
Action: FINAL RULE
The FWS has designated designate 13 river and stream segments in the Tennessee Cumberland River Basins, for a total of approximately 885 river as critical habitat for five endangered mussels: Cumberland elktoe (Alasmidonta atropurpurea), oyster mussel (Epioblasma capsaeformis), Cumberlandian combshell (Epioblasma brevidens), purple bean (Villosa perpurpurea), and rough rabbitsfoot (Quadrula cylindrica strigillata). All five mussels belong to the Unionidae family.
- 10/12/00, the Southern Appalachian Biodiversity Project filed a lawsuit in U.S. District Court for the Eastern District of Tennessee against the FWS challenging the FWS’not-prudent critical habitat determination for the 5 Cumberlandian Region mussel species.
- 11/8/01, the District Court issued an order directing the FWS to re-evaluate the prudency determination for these five mussels and submit new proposed prudency determinations for the Cumberland elktoe to the Federal Register no later than 5/19/03, and for the remaining four mussels to the Federal Register no later than 6/16/03.
- 1/8/04, the District Court extended FWS’ deadline to submit the final rule to the Office of the Federal Register to not later than 8/19/04.
- 10/6/03 – 12/5/03, the comment period was reopened for submission of comments on a draft economic analysis, a technical correction and possible modification of Unit 8 Rock Creek, and to accommodate a public hearing which was held on October 29, 2003, in Tazewell County, Virginia (68 FR 57643).
- The five mussels live embedded in the bottom sand, gravel, cobble substrates of rivers and streams.
- The five mussels also have a unique life cycle that involves a parasitic stage on host fish. The presence of suitable host fish is considered an essential element in these mussels' life cycles.
- Because of their life cycle, small population sizes, and limited habitat availability, they are highly susceptible to competitive or predaceous nonnative species.
Five Elements that Critical Habitat is Designated to Protect for the Five Mussels
- Permanent, flowing stream reaches with a flow regime necessary for normal behavior, growth, and survival of all life stages of the five mussels and their host fish;
- Geomorphically stable stream and river channels and banks;
- Stable substrates, consisting of mud, sand, gravel, and/or cobble/boulder, with low amounts of fine sediments or attached filamentous algae;
- Water quality necessary for the normal behavior, growth, and survival of all life stages of the five mussels and their host fish; and
- Fish hosts with adequate living, foraging, and spawning areas for them.