EFFECT OF CYCLING TEMPERATURES ON ELECTROLYTE BALANCE IN SKELETAL MUSCLE AND PLASMA OF RAINBOW TROUT SALMO GAIRDNERI

1. 1. Rainbow trout, Salmo gairdneri (1 1 2 yr old), were acclimated to a daily temperature cycle ranging from 8 to 18°C. 2. 2. Control fish were maintained at constant temperatures which coincided with sample temperatures of the cycling fish. 3. 3. Sodium, potassium, chloride and water were measured in the plasma and muscle of all the fish. 4. 4. In most cases the plasma ion levels in the cycling fish did not exceeded those levels of the control fish which were held at low temperatures (8-10°C). 5. 5. There was a highly significant inverse relationship between the muscle potassium and the muscle sodium levels in the cycling fish. © 1969.