The purpose of this study is to provide critical information for restoration of the LAWA Freshwater Mussels. We propose to survey the distribution of the LAWA Freshwater Mussels, where mussels may be extinct, and test whether genetic differences exist among groups by examining aggregations in LAWA and an outgroup using microsatellite DNA variation. The project is innovative because it proposes using recently developed DNA technology (microsatellite DNA) to examine potential genetic variation in species for which nothing is known. The project is also innovative because we will use qualitative surveying techniques developed elsewhere for freshwater mussels to do the first systematic survey of freshwater mussels in LAWA. Both these objectives provide information that will be useful for similar projects elsewhere. We chose LAWA Freshwater Mussels, because (1) they were vital components of intact salmonid ecosystems that have been affected directly and indirectly by docks, fills, dumping, habitat deterioration, and decline in salmon; (2) they were culturally important to Native Americans; and (3) they have been ignored by managers and researchers in LAWA. Molecular characterization of LAWA Freshwater Mussels from this project may also provide an innovative tool to study and understand ecological interactions between mussels and salmon during ecological recovery by providing a technique to identify glochidia, the life history stage when mussels use salmon as hosts.