Barotrauma in Juvenile Salmonids Exposed to Simulated Hydroturbine Passage: pathways, management implications and applications

On their seaward migration, juvenile salmonids commonly pass hydroelectric dams. Barotrauma (e.g., swim bladder rupture, hemorrhaging, emboli and exopthalmia) resulting from rapid decompression can be a major source of injury and mortality during turbine passage. The mechanisms of these injuries can be due to expansion of existing bubbles or gases coming out of solution; governed by Boyle\u27s Law and Henry\u27s Law, respectively. It appears that the majority of decompression related injuries observed in juvenile salmonids exposed to simulated turbine passage are due to the expansion of existing bubbles in the fish, particularly the expansion and rupture of the swim bladder. This information is particularly useful for fisheries managers and turbine manufacturers. Reducing the rate of swim bladder ruptures by reducing the frequency of occurrence and severity of rapid decompression during hydroturbine passage could reduce the rates of injury and mortality for hydroturbine passed juvenile salmonids. However, there is little information about how other species, with varying physiological and morphological characteristics (e.g., type of swim bladder), will be influenced by changes in pressure. The implications for fisheries management, hydro management and development and broadening the range of understanding of barotrauma in both salmonids and non-salmonid species will be presented