PNNL

Abstract

The swimbladders of juvenile rainbow trout Onchorhynchus mykiss were ruptured and subsequently observed for 28 days to identify healing patterns of swimbladder wounds and the effects of swimbladder rupture on direct mortality. Healing began within seven days, wounds were completely closed after 14 days, and no mortalities occurred. The healing process followed a pattern in which tissue first thickened around the opening (7 to 14 days), followed by scarring of the ruptured area, and disappearance of any evidence of the wound (21 to 28 days). The healing observed in juvenile rainbow trout swimbladders suggests that swimbladder rupture does not result in direct mortality as was hypothesized; however, the indirect effects of swimbladder 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.