MODERATE EXERCISE DECREASES PLASMA-CORTISOL LEVELS IN ATLANTIC SALMON (SALMO-SALAR)

1. Atlantic salmon, Salmo salar, subjected to moderate exercise (0.5 body length/sec) for 24 hr showed a significant decrease in plasma cortisol levels, after an initial sharp peak, compared to controls kept in still water. 2. These findings indicate that the exercising salmon at 0.5 bl/sec have reduced stress levels which may account for the increase in growth described in trained salmonids.