Effects of declining calcium availability on the survival, growth and calcium content of a freshwater crayfish,Orconectes virilis

Year of Publication
Calcium (Ca) decline is a severe and widespread phenomenon threatening softwater ecosystems around the world. In north temperate lakes, these declines have been linked with declines in numerous freshwater taxa, in particular, crustacean zooplankton and crayfish.The purpose of this study was to determine, under lab conditions, the effect of low Ca concentrations on survival, growth and Ca content of a freshwater crayfish, Orconectes virilis, originating in a region experiencing Ca decline.We found that survival of juvenile O. virilis was significantly reduced at 0.5-0.9 mg L-1, which is among the lowest requirement reported for a freshwater crayfish. Neither growth nor whole-body Ca content were related to Ca concentration.Based on these findings, the acute tolerance of O. virilis to low Ca may allow the species to persist under forecast concentrations of lakes in regions experiencing Ca decline; however, most lakes are experiencing stress from multiple environmental agents which could influence the impact of Ca on mortality and potentially other life history attributes.