The effects of environmental salinity on tissue respiration of the starry flounder (Platichthys stellatus)

The standard metabolic rates of the euryhaline starry flounder (Platichthys stella.tus) when acclimated to 30 parts per thousand (‰) and 10.8 parts per thousand (isotonic to plasma) salinities are not significantly different. However, the standard metabolic rate is significantly lower in fish acclimated in 2‰ salinity. Metabolic rate was directly proportional to the frequency of an electrical stimulation of 60 volts to a maximum frequency of 3 stimulations per minute. An estimate of the standard metabolic rate was obtained by extrapolating the activity curve to a stimulation frequency of zero. Although the estimate was similar to previously determined standard metabolic rates the confidence intervals were too great to allow detailed comparisons. QO₂ of each major organ was obtained from three groups of fish held in the three salinities. Only gill showed a significant change with regard to salinity. The QO₂ was least in the isotonic salinity and was significantly greater in both higher and lower salinities. A summation value of tissue respiration was obtained for each group of fish. The summated tissue values were below the standard metabolic rates of fish in 30‰ and 10.8‰ salinity but above the standard metabolic rate of fish in 2 ‰ salinity although they did not significantly differ from each other.Science, Faculty ofZoology, Department ofGraduat