Condition factor dependency of burst swimming ability between wild and hatchery-reared chum salmon fry (Oncorhynchus keta)

Burst swimming velocity ( U burst ) was compared between wild and hatchery-reared chum salmon fry. In the hatchery-reared fry, U burst was significantly correlated with the condition factor, but not with the body mass and fork length. In the wild-reared fry, on the other hand, U burst ranged widely and did not correlate with condition factor. These suggest that well-balanced growth under satisfactory nutrient condition at the early developmental stage improves U burst , and in the wild-reared fry, their cautiousness and various experiences may override the condition factor dependency of U burst .