Physiology of Finfish and Shellfish (2+1)

4.4.3. Effect of oxygen concentration on metabolic rate

At high temperature, the oxygen consumption is higher that at low temperature, but at any one temperature the oxygen uptake is linearly related to the available oxygen.

If the oxygen uptake is studied over a wider temperature range in an animal such as the goldfish, we can obtain the relationship shown in Figure 6.2. At relatively high oxygen tension, the oxygen uptake of goldfish is independent of the available oxygen, but at lower oxygen tensions there is a linear relationship. The inflection point, which indicates, where the oxygen uptake changes from concentration dependence to independence, is lower at low temperature than at high temperature.

The straight-line relationships could be observed for lobsters may indicate which the lower part of curves of the same general shape as the goldfish curves. If this is so, we can expect that the curves for lobsters at some unknown higher oxygen concentration would level off and become independent of further increases in oxygen.