Effects of prolonged exercise training and exhaustive chasing training on the swimming performance of an endangered bream Megalobrama pellegrini

Swimming performance of fish is often improved following periods of moderate exercise training. To examine the effects of training regimes on swimming performance of juvenile bream Megalobrama pellegrini (5.10 ± 0.08 g), fish were held in slow-flowing water (control), or subjected to exercise training at 1 body length (BL) s−1, 2 BL s−1 or 4 BL s−1, or were given exhaustive chasing training daily for 5 wk at 25°C. Aerobic swimming performance was assessed by measuring critical swimming speed (Ucrit). Maximum metabolic rate (MMR), metabolic scope (MS), cost of transport (COT) and net cost of transport (COTnet) were assessed by measurement of oxygen consumption rates ( · MO2). Ucrit was significantly higher in the 4 BL s−1 training group than in the controls. The value of Ucrit was 5% greater for the exhaustive training group compared with the control group, although exhaustive chasing training did not have a significant effect on Ucrit. MMR and MS were not significantly different across treatments. · MO2 and COT of fish in the 4 BL s−1 and exhaustive training groups were significantly lower than in the control group in the swimming speed range of approximately 36−60 cm s−1. This suggests that high-intensity prolonged exercise training and exhaustive chasing training have a positive influence on the swimming performance of juvenile M. pellegrini, which may be related to elevated anaerobic metabolism and improved swimming efficiency.