A multi‐basin approach determines variability in host fish suitability for unionids in tributaries of the Laurentian Great Lakes

Abstract

Summary Freshwater mussel populations have declined, in part, from changes in host communities. However, it is unknown if fish from adjacent catchments could be used to augment mussel populations in the Great Lakes inland rivers, and if so, whether this association would be impacted by known genetic structure in mussels and fish. This study tested how host fish origin (i.e. catchment) impacts the transformation of the endangered unionid Epioblasma triquetra from larval into juvenile life stages while concurrently considering potentially genetically distinct populations of mussels and hosts. We quantitatively determined if Percina caprodes and Percina maculata from the Lake Michigan, Erie and Huron basins are laboratory‐successful hosts for E. triquetra. Experiments were performed in autumn and spring to document any seasonal effects on transformation. Percina caprodes was reconfirmed to be a successful host for E. triquetra, and for the first time, P. maculata was also determined to be a successful host in the Great Lakes region. Results suggest no differences in juvenile transformation with allopatric and sympatric fish and mussel pairings based on Great Lakes basin origin; therefore, transformation success may not parallel differences in genetic structure. In addition, results suggest seasonal differences in the developmental stages of E. triquetra juveniles. Knowing the most efficient strategy to optimise juvenile transformations can make reintroductions, augmentation and overall conservation efforts of E. triquetra successful. These data will help in developing recovery strategies for E. triquetra in the Laurentian Great Lakes by understanding variation in host use and nuances in this host–parasite relationship.