The Physiological Ecology of the Zebra Mussel, Dreissena polymorpha, in North America and Europe

TLDR: Literature review indicates agreement on most as?

Abstract: Synopsis. The zebra mussel, Dreissena polymorpha (Pallas), was intro? duced into North America in 1986. Initial North American (N.A.) studies suggested that physiological responses varied between N.A. and European populations. However, literature review indicates agreement on most as? pects of physiological adaptation including: respiratory responses; hypoxia/anoxia tolerance; salinity limits; emersion tolerance; freezing resis? tance; environmental pH limits; calcium limits; starvation responses; and bioenergetic partitioning. The main differences among N.A. and European mussels appear to be elevated upper thermal limits and temperatures for optimum growth among N.A. populations. N.A. zebra mussels probably originated from the northern shore of the Black Sea in the warmest por? tion of the mussel's European range. However, most European physio? logical data come from northern Europe where populations may be adapt? ed to colder temperatures. Alternatively, N.A. research suggests that mus? sels may have a capacity for seasonal temperature acclimatization such that responses recorded in warmer N.A. waters may be different from those recorded in northern Europe even after short-term laboratory accli? mation. Studies of genetic variation and physiological response among European and N.A. D. polymorpha populations are required to elucidate the basis for physiological differentiation. Recently evolved D. polymor? pha has poor resistance adaptations compared to unionacean and sphaeriid bivalves with longer freshwater fossil histories. Poor resistance adapta? tions make it less suited for stable habitats, instead, its high fecundities, early maturity, and rapid growth are adaptations to unstable habitats where extensive resistance adaptations are of little value.