SOME EXPERIMENTS ON THE OXYGEN CONSUMPTION OF GOLDFISH (CARASSIUS AURATUS L.) IN RELATION TO SWIMMING SPEED

Abstract

This investigation was designed to measure the relation between the oxygen consumption of fish and their swimming speed. Experiments were performed with the aid of an annular fish chamber, which can be rotated at will, and by means of Blazka's apparatus, in which the fish swims against a water current produced by a rotating propeller.Oxygen consumption increases with swimming speed. Beyond a speed of about 0.5 body lengths per second, however, the goldfish passes to another type of swimming and by doing so, it is able to reach approximately four times this speed at the same rate of oxygen uptake.Extrapolation of the line relating speed and oxygen consumption to zero activity gives the value of standard metabolism. The actual oxygen uptake minus this standard value is taken as a measure of the energy expenditure of the propulsion muscles.Excitement appears to raise the fish's oxygen consumption sharply, even without any increase of its locomotor activity.Both excitement and anaerobic metabolism can vitiate the reliability of power calculations based on the rate of oxygen uptake. Only rates found when the fish is not excited may be used to calculate the energy spent by the fish in swimming. Simultaneous measurements of carbon dioxide production and oxygen uptake are probably required to obtain an estimate of the rate of anaerobic metabolism.