The Influence of Swimming Efforts on Barotrauma Susceptibility

Barotrauma can occur in fish when they are rapidly decompressed, such as occurs during hydro-turbine passage.  Previous research has examined barotrauma induced by simulated turbine passage using various hyper/hypobaric hydro-chambers.  These chambers were primarily designed to single out pressures as a solitary variable, allowing researchers to determine specifically how pressure changes will affect fish with minimal confounding variables.  However, additional variables in synchrony with pressure should also be explored to determine their influence on barotrauma.   One such variable is swimming efforts during decompression.  Gas bubble formation associated with exercise and decompression research has predominantly focused on reducing decompression sickness associated with SCUBA diving, aviation, and space flight.  It has been suggested to avoid physical exercise prior to diving, based on the concept that exercise prior to decompression may increase inert gas bubbles within blood and tissues during decompression.  However, recent research suggests that exercise prior to decompression may reduce the presence of gas bubbles post-decompression.  Inserts for hyper/hypobaric hydro-chambers were developed allowing researchers to simulate pressures and water velocities that fish may experience during hydro-turbine passage.  These inserts were used to examine the effects of swimming efforts on barotrauma susceptibility in Murray cod (Maccullochella peelii) and silver perch (Bidyanus bidyanus).