Respiratory, osmoregulatory and behavioural determinants of distribution of tropical marine hermit crabs

The hermit crabs Clibanarius taeniatus and Clibanarius virescens are common tropical species on the rocky intertidal shores of Queensland, Australia. This area is frequently hot and dry with temperatures in excess of 38°C. Sudden, heavy rains in river catchments and local coastal areas often result in flood events that dilute coastal waters, exposing hermit crabs to prolonged periods when salinity is as low as 14% seawater (SW), while extreme evaporation may result in tidepool concentrations of up to 125% sw. Such conditions in the intertidal area result in the combined stresses of fluctuating temperature, salinity and oxygen availability, resulting in the need for physiological tolerances and/or behavioural changes.