Effects of lower jaw deformity on swimming performance and recovery from exhaustive exercise in triploid and diploid Atlantic salmon Salmo salar L.

Lower jaw deformity is a common deformity in cultured triploid Atlantic salmon in Tasmania. However, the physiological effects of this deformity have not been studied. Swimming performance and anaerobic capacity were assessed in sibling diploid, triploid and triploid with lower jaw deformity all female Atlantic salmon. There were no significant differences in the critical swimming speed attained by any of the groups of salmon. However, a second swim challenge after a recovery period of 45 min revealed that triploid salmon with lower jaw deformity were not capable of attaining the same critical swimming speed as in their first test. There was a positive correlation between the severity of the lower jaw deformity and the extent to which recovery between swimming bouts was compromised. Oxygen consumption rates (both routine and maximal) as determined after a bout of exhaustive exercise were identical between all groups of salmon but triploid and triploid with lower jaw deformity fish had a lower excess post-exercise oxygen consumption and recovered their oxygen consumption to pre-exercise levels quicker than diploid fish. This suggests that the aerobic capacity of the fish was not necessarily adversely affected by ploidy or LJD but that but that recovery from exhaustion was affected by jaw deformity. In exhausted fish, triploids and in particular those with skeletal deformity, recovery of EPOC was quicker than with diploids potentially as a result of either not accruing the same oxygen debt or else having the ability to repay the oxygen debt more quickly.