Oxygen metabolism of farmed turbot ( Scophthalmus maximus) : I. The influence of fish size and water temperature on metabolic rate

The use of fish farm production and fry tanks as large-scale respirometers proved very effective. The high stocking densities maintained in the tanks, resulted in a rapid decline in dissolved oxygen saturation after water and oxygen supplies were interrupted. The measurement of this decline together with fish biomass and number, water temperature, salinity and atmospheric pressure enabled the oxygen consumption rate of the fish to be calculated as a function of body weight. Fish size on the farm ranged from 4 to 1000 g and over a period of 2 years, oxygen consumption determinations were made at temperatures ranging from 7 to 16°C. The relationship between oxygen consumption rate and mean weight of the fish was fitted statistically into five temperature groups of 2°C spread, i.e. 7–8°C, 9–10°C, 11–12°C, 13–14°C, 15–16°C. The relationship between oxygen consumption rate, fish size and temperature was similar to that of salmonids, although the rates of oxygen consumption were only about one half.