Preventing Barotrauma in Fish During Passage of Hydro and Irrigation Structures: A Recipe for Global Success

Demand for hydropower, irrigation, and flood control is increasing in many countries, especially developing countries where fish are the major protein source of subsistence communities.  Since fish play such an important role in the lives of people in these areas, it is important that fish productivity and diversity is not lost due to this development.  Significant advances in understanding the mechanisms responsible for fish injury and mortality during hydroturbine passage have been made in recent years.  Barotrauma (e.g., swim bladder rupture, hemorrhaging, emboli and exopthalmia) resulting from rapid decompression can be a major source of mortality during turbine passage but most research to date has focused on salmonids.  There is little information about how other species, with varying physiological tolerances, will be influenced by changes in pressure.  The amount of gas present in the swim bladder as a fish approaches and passes hydro facilities can dramatically influence survival rates.  Thus research needs to be conducted to determine how many species regulate their buoyancy.  Research on some important aspects of the structure and function of the swim bladder can be answered with fairly simple and inexpensive tools.  This could allow research to be initiated quickly in many countries.