Metabolic Thermal Compensation by Rainbow Trout: Effects on Standard Metabolic Rate and Potential Usable Power

Abstract

Abstract Metabolic models of thermal acclimation of fishes are generally based on routine rates of oxygen consumption and, therefore, are confounded by metabolic changes due to variation in random activity. My objectives were to describe the amount, direction, and time course of change in the standard metabolic rate of rainbow trout Oncorhynchus mykiss while the fish acclimated to warm and cold temperature, and to account for the energy costs of random swimming. Rainbow trout (100–250 g) were acclimated to 10 and 20°C and tested at 10, 15, and 20°C. Random activity and oxygen consumption were monitored at acclimation temperatures immediately after acute temperature exposures and, in some cases, for several days after temperature changes. Random swimming activity and standard metabolic rate were strongly influenced by both recent thermal history and acute temperature exposure. The initial activity response depended on the extent of the temperature change, and included an orthokinetic reaction when the new ...