Temperature Tolerances and Osmoregulation in some Estuarine Bivalves

Abstract

The salinity and temperature tolerances of some burrowing bivalves which occur in the middle reaches of the Swartkops estuary have been studied. Five species (Solen caperats, S. comeus, Dosinia hepatica, Macoma litoralis and PsammotelUna capensis) have upper lethal temperatures of 41-46°C when heated at a rate of 1 °/10 minutes. Two species have upper lethal temperatures of 37°C and 39°C when heated at a rate of 1 C°/day. It has been concluded that they can tolerate much higher temperatures than they normally encounter in the estuary.