Continuous Monitoring of Respiration in Production Scale Trout Culture

Abstract

The DAI experimental farm for culture of Rainbow Trout (Salmo gairdneri) in heated saltwater was established in December 1982. The average yearly net production has in this period been 40 to 50 tons/year. In the three years have now been conducted production scale experiments and data collection on growth, diseases, food conversion, acclimatization to saltwater, energy demands and respiration.The fish respiration is of primary importance for the production economy and as background for developing good fishfarming practices. For this reason, has in chosen basins been established a continuous measurement of oxygen in inlet and outlet and of waterflow through the basin. The data are collected and processed through a small microcomputer. Because of the high fish density, app. 25 kg/m2, the total oxygen demand is completely dominated by the fish respiration, so this figure can be calculated from the abovementioned measurements. The results of the calculations have been normalized to a given temperature, and are presented as a function of fish size in the interval from 300 to 2000 gram.