Physiological and biochemical condition of native freshwater mussels associated with a relocation in Lake St. Clair

Relocation of native freshwater mussels is often used as a conservation and management strategy by resource managers.  However, there are few biological or physical criteria from which to compare the acceptability of potential relocation sites.  Our objective was to determine if we could use biochemical (fatty acids, FA) and physiological (tissue condition, glycogen) metrics in mussels as indicators of food availability and habitat quality at potential relocation sites.  This work was conducted in the delta area of Lake St. Clair—an important refuge for native mussels in the Great Lakes.  We relocated 2 species of mussels from a single source location (2004) with high zebra mussel infestation rates to two areas with lower zebra mussel infestation and assessed the condition of resident (2004-05) and relocated (2005) individuals.  Glycogen concentrations were similar among source, resident, and relocated mussels.  In contrast, tissue condition and FA concentrations varied among source, resident, and relocated mussels.  Multivariate analyses indicate that glycogen and estimates of bacterial fatty acids are strongly associated—suggesting that mussels may be utilizing bacterially-derived food resources more than expected.  This approach may provide insight into the quality of habitat and available food resources at potential relocation sites.