The effect of temperature on the resting and post-exercise metabolic rates and aerobic metabolic scope in shortnose sturgeon Acipenser brevirostrum.

Abstract

The effects of acclimation temperature (15, 20, 25°C) on routine oxygen consumption and post-exercise maximal oxygen consumption rates (MO2) were measured in juvenile shortnose sturgeon (Acipenser brevirostrum LeSueur, 1818). The routine MO2 of shortnose sturgeon increased significantly from 126.75mg O2h-1kg-1 at 15°C to 253.13mg O2h-1kg-1 at 25°C. The temperature coefficient (Q 10) values of the routine metabolic rates ranged between 1.61 and 2.46, with the largest Q 10 values occurring between 15 and 20°C. The average post-exercise MO2 of all temperature groups increased to a peak value immediately following the exercise, with levels increasing about 2-fold among all temperature groups. The Q 10 values for post-exercise MO2 ranged from 1.21 to 2.12, with the highest difference occurring between 15 and 20°C. Post-exercise MO2 values of shortnose sturgeon in different temperature groups all decreased exponentially and statistically returned to pre-exercise (resting) levels by 30min at 15 and 20°C and by 60min at 25°C. The aerobic metabolic scope (post-exercise maximal MO2-routine MO2) increased to a maximum value ∼156mg O2h-1kg-1 at intermediate experimental temperatures (i.e., 20°C) and then decreased as the temperature increased to 25°C. However, this trend was not significant. The results suggest that juvenile shortnose sturgeon show flexibility in their ability to adapt to various temperature environments and in their responses to exhaustive exercise.