Investigations on the respiration of the Neotropical fish, Co lossoma macropomum (Serrasalmidae) The influence of weight and temperature on the routine oxygen consumption

Abstract

The influente of weight and temperature on the routine oxygen consumption of Colossoma macropomum, a Neotropical fish species of the faínily Serrasalmidae, was investigated using a constant flow respirometer. Plotted on a double logarithmic grid, oxygen consumption increases linearly with weight. Slopes of 0.64 at 25 and 30 'C, and 0.78 at 35 "C were obtained. Because of the significant difference in the slopes, a general value could not be provided. The metabolic rate of a 100 g fish inueases from 103.7 to 191.5 and 289.7 mg 02/kg/h at 20,25, and 30 "C, respectively. At 35 OC, the oxygen consumption rate deaeased to 212.4 rng 02/kg/h. The metabolic rate is comparable to those of other tropical fish species. Obviously, Colossoma macropomum is weii adapted to theconstant temperature conditions of its Neotropical habitats.