Life history of the endangered shiny pigtoe pearly mussel, Fusconaia edgariana, in the North Fork Holston River, Virginia

The life history of Fusconaia edgariana, the endangered shiny pigtoe pearly mussel, was determined in a two-year study at North Holston Ford, North Fork Holston River (NEHRM 86.9) above Saltville, Virginia. Sixty 0.5m² Quadrats indicated a mean density of 10.6 mussels/m², representing 1 species. Six additional species were collect handpicking or in muskrat middens. The density edgariana was 1 adult/2 m². Distribution of the pigtoe was restricted to shallow areas of mixed gravel, and pebble substrate in low to moderate velocities.

Drift nets (130um mesh) indicated glochidia edgariana were released into the water column from 23 June to 18 August, 1981 and 24 June to 28 August, 1982. Of the 4,800 fish examined from June 1981 to June 1982, 1.5% carried shiny pigtoe glochidia. The telescope, common, warpaint, and whitetail shiners were found naturally encysted by 1 to 3 glochidia of F. edgariana. Laboratory induced infestations were conducted on twenty two species of fish, and all but two species sloughed the glochidia within 4 to 14 days. The whitetail and common shiners retained glochidia for 38 days, indicating these two fish species to be probable hosts for the shiny pigtoe.