Metabolic response to thermal changes of the adult fiddler crab Uca pugilator and the effect of PCBs

Abstract

Although polychlorinated biphenyls (PCBs) are widespread in the environment, their influence on functional characteristics of marine animals is poorly known. This paper presents data on the relative effects of a sublethal concentration (50 ppb) of Aroclors® 1016 and 1254 on the respiratory metabolism of the fiddler crab Uca pugilator (Bosc.), an intertidal, estuarine inhabitant. At 25°C, the respiration rate of both males and females increased initially after exposure to these Aroclors. After the crabs were returned to uncontaminated seawater, their respiratory rates were similar to initial pre-exposure values. At 15°C, Aroclors 1016 and 1254 had no apparent effect on the respiration of males but depressed that of females. Upon exposure to PCB-free seawater, the metabolic rate of both male and female crabs was similar to initial pre-exposure rates. At 35°C, a trend existed for both of these PCBs to inhibit respiration. In a series of experiments on cold- and warm-acclimated individuals, PCBs did not consistently influence metabolic response over the thermal range of 10° to 30°C.