Survival and condition of riverine freshwater mussels (Unionidae) confined in cages suspended in ponds

Abstract

The survival of 1,729 freshwater mussels (15 species) was monitored in ponds at study sites in Critz, Blacksburg and Marion, Virginia. Mussels were held within plastic and metal screen cages fastened to PVC float collars. Survival in the pond at Critz was 73% overall, with significant differences in survival among species after 26 months of captivity. Cyclonaias tub~X_~lJ.t~J_~ and three E11Jptt9 spp. exhibited the highest survivals (x=83%), whereas survival of Pleurobema cordatum and Lampsilis ovata was significantly lower, with 54% and 14%, respectively. Survival of five mussel species in a pond at Blacksburg was high (x=79%) after 7 months, but a nearly complete die-off of captive mussels occurred during hot weather in July, 1994. Survival of six mussel species at the Marion state Fish Hatchery was low for both the sleeve and unrestricted holding methods, 35% and 8%, respectively, after 14 months. It is suspected that excessive accumulation of particulates from pelleted feed contributed to the low survival observed at this site. Survival of four mussel species at Hoge's Pond in Blacksburg was 98% after 6 month.