The effect of exhaustive exercise on the thermal tolerance of brook charr (Salvelinus fontinalis)
University of New Brunswick
This study examined whether exercise influences acute thermal tolerance in brook charr (Salvelinus fontinalis). To address this, fish were assigned to one of 4 groups (i) control; (ii) 5-minute exhaustive exercise; (iii) thermal stress only; and (iv) 5-minute exhaustive exercise prior to thermal stress. Blood samples were also taken from the fish to measure stress parameters (plasma lactate and glucose) between the groups. Acute thermal tolerance, measured as the temperature where the fish lost equilibrium, were similar between fish exposed to thermal stress only and fish exposed to exercise prior to the thermal stress (30.2 ±0.5C and 29.6±0.8C, respectively). However, blood lactate and glucose were about 25% higher in charr exercised prior to the thermal stress (lactate 8.2 mmol/L and glucose 9.5mmol/L). These findings show that there are no differences in the thermal tolerance between groups, but there are additional physiological effects in fish exercised prior to thermal stress.