The Relation of Temperature to Oxygen Consumption in the Goldfish

Two levels of oxygen uptake, (1) the lowest point in the resting metabolism in the daily cycle and (2) the maximum steady rate of oxygen uptake found when the fish were stimulated to activity in a rotating chamber, were measured at temperatures from 5° to 35° C. 2. The standard (resting) rate was measured over levels of oxygen high enough to avoid any dependence of the rate on oxygen tension. The maximum rate was measured over a series of oxygen tensions down to the asphyxial level. 3. The standard rate continued to increase with temperature up to 35° C., the highest temperature at which observations were made. The maximum rate was found by interpolation to reach its highest value at about 30° C. and to remain steady or decrease slightly at higher temperatures. 4. The maximum rate of oxygen uptake became dependent upon the oxygen tension between 15 and 40 mm. Hg, depending upon the temperature. These estimates were made in a closed system in which there was an accumulation of the carbon dioxide released in respiration. 5. Oxygen tensions at which the maximum oxygen uptake met only the needs of the standard metabolism were estimated to be between 4 and 25 mm. Hg over the temperature range investigated. 6. At the various temperatures the difference between the maximum and standard metabolic rates is correlated with the rate at which goldfish can swim steadily. 7. It is concluded that the drop in the sustained swimming rate of goldfish at temperatures from 30° to 38° C. is probably due to a decrease in the metabolism available for external work rather than to the thermal destruction of enzymes.