The Effects of Starvation and Cold on Resting Metabolism of Arctic char (Salvelinus alpinus)
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Date
2023-03
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University of New Brunswick
Abstract
To cope with prolonged frigid temperatures and limited resource availability over winter, Arctic char have an overwintering strategy involving reductions in activity and fasting for up to 10 months, to minimize energy expenditure. I characterized the effects of cold and starvation on Arctic char standard (resting) metabolic rate (SMR) to determine if they confer additional energy savings beyond those achieved through inactivity. Experimental fish were acclimated to 2℃ or 8℃ in combination with either feeding or starvation. Oxygen consumption and activity were measured simultaneously and oxygen consumption at zero activity (resting) was determined to examine how SMR was affected by temperature and feeding condition. Starvation resulted in a ~40% reduction in SMR at both temperatures, suggesting a similar depression of resting energy demands during food deprivation regardless of temperature. The SMR of fish at 2°C was ~39% lower than those at 8°C (Q10=2.3) in both feeding treatments, indicating typical passive slowing of SMR in the cold. The combination of cold and starvation resulted in a ~64% decrease in SMR relative to fed fish at 8°C. Thus, cold and starvation drive reductions in Arctic char resting metabolism independently, and additively, which is likely central to energy conservation over winter.