Healing Rate of Swim Bladders in Rainbow Trout

Swim bladders Of juvenile rainbow trout Oncorhynchus mykiss were ruptured and subsequently observed for 28 d to identify healing patterns of swim bladder wounds and the effect of swim bladder rupture on direct mortality. Healing began within 7 d, wounds were completely closed after 14 d, and no mortality occurred. The healing process followed a pattern in which tissue first thickened around the opening (7-14 d), scarring of the ruptured area occurred. and evidence of the wound ultimately disappeared (21-28 d). The healing observed in juvenile rainbow trout suggests that swim bladder rupture does not result in direct mortality as was hypothesized however. the indirect effects of swim bladder injury (e.g., a decreased ability to swim efficiently) may lead to mortality by predation or other natural phenomena that were not observable in this study.