Physiology and survival of triploid brook trout following exhaustive exercise in warm water

Abstract

We investigated the effects of chronic high temperature (19 °C) on the post-exercise recovery processes in diploid and triploid brook trout. For these experiments, we measured the metabolic fuels glycogen, phosphocreatine (PCr) and ATP in the white muscle, and the muscle [lactate], plasma [lactate], plasma [glucose], plasma osmolality and blood hemoglobin levels before, following, and during recovery from exhaustive exercise. Although both diploids and triploids responded metabolically to exercise, the magnitude of the response was different between ploidies. In particular, triploids used less PCr and more glycogen than diploids. Also, the patterns of metabolic recovery were different between diploids and triploids. In addition to triploid trout having difficulty utilizing anaerobic pathways, these fish took longer to recover from the metabolic disturbance. This lack of recovery of the metabolites at warmer temperatures in triploids might be a contributing factor to the increased mortality of these fish: 9 of 10 triploids died within 4 h of exposure to 19 °C, whereas none of the diploids died.