Thermal variation near the thermal optimum does not affect the growth, metabolism or swimming performance in wild Atlantic salmon (Salmo salar).

Typically, laboratory studies on the physiological effects of temperature are conducted using stable acclimation temperatures. However, information extrapolated from these studies may not accurately represent wild populations living in thermally variable environments. Our objective was to compare the growth, metabolism, and swimming performance of wild Atlantic salmon exposed to cycling 16-21(o) C, and stable 16(o) C, 18.5(o) C, 21(o) C acclimation temperatures. Growth rate, metabolic rate, swimming performance, and anaerobic metabolites did not change among acclimation groups, suggesting that within Atlantic salmon's thermal optimum range, temperature variation has no effect on these physiological properties. This article is protected by copyright. All rights reserved.