Effects of Acute Temperature Change and Temperature Acclimation on the Respiratory Metabolism of the Snakehead

The effects of acute temperature change and the following two weeks of acclimation from the initial 25 degrees C to 15, 20, 30, and 35 degrees C on the respiratory metabolism of the snakehead (Channa argus), a species tolerant to wide temperature range were examined in this study. The resting metabolic rate (RMR), ventilation frequency (VF), and several hematological parameters were determined. RMR of the fish post either acute temperature change or chronic acclimation was positively correlated with temperature, and exhibited V-shaped Q(10) values change vs temperature, which suggests that the snakehead has a varying thermal metabolic sensitivity dependent on temperature range. The decreased Q(10) value for RMR post chronic acclimation suggests that the metabolic thermal sensitivity of the snakehead can be reduced by acclimation. The VF increased with increasing temperature slower than RMR, which suggests that regulation of VF alone may not be sufficient to satisfy the oxygen demand of the snakehead as temperature increases. Cold compensation was observed in VF, but not RMR, which could be due to a decreasing oxygen exchange capacity of the gill during cold acclimation. Thus, the compensation in VF of cold acclimated fish may be necessary to maintain oxygen supply.