Influence of temperature on the behaviour and physiology of Atlantic salmon (Salmo Salar) on a commercial farm

Abstract

Commercial Atlantic salmon (Salmo salar) farms face challenges under climate change, as rising sea temperatures and higher variability in weather patterns can lead to thermal stress events, compromising fish health, and resulting in lower production efficiency. Temperature plays a critical role in influencing the physiological and behavioural response of salmon under stressful conditions and effective farm management requires a nuanced comprehension of its function to adjust farming practices and minimize further stress. Two types of biologgers, measuring external acceleration, depth, heart rate, and temperature were surgically implanted for 245 days to explore the effects of the thermal response of Atlantic salmon during a standard production cycle. Apparent heart rate scope and Arrhenius breakpoint temperature were used to estimate the optimal temperature and both methods resulted in an estimate of 12.7 °C. There was a reduction in apparent heart rate scope at temperatures below 2 °C and >19 °C suggesting proximity to limits of thermal stress. The use of biologgers facilitates direct observations in commercial operations, providing essential information for aquaculture management. These findings contribute to a holistic understanding of the effect of temperature influencing Atlantic salmon physiology and behaviour on aquaculture farms, bridging the gap between controlled laboratory studies and real-world commercial operations.