Freshwater mussels of the Unionoida have a complex life cycle which includes the release of glochidia, mussel larvae that need to attach to a host fish for further development (Barnhart et al., 2008). The attachment of glochidia to either the skin or gill tissue of the fish host is controlled by an ion gradient (Lefevre and Cutis, 1912).As such, the use of saturated salt solutions is used to assess valve closure responses of glochidia as a measure of viability in toxicity studies (ASTM E2455—06, 2006) and for host infections in conservation programs (Taeubert et al., 2012, 2013a).