It is widely accepted that hydroelectric dams have a significant effect on migratory fish species. Ireland has four major catchments harnessed for hydroelectricity. Atlantic salmon populations above hydroelectric installations in these systems are significantly reduced or extinct, and the available literature on the potential problems associated with dam passage is limited. Mitigation of salmon population losses has centred mainly on the stocking of rivers upstream of hydroelectric installations with juvenile, hatchery-reared fish. This form of mitigation has largely failed to produce a returning stock of spawning fish. It is clear that problems associated with the safe migration of salmon past hydroelectric facilities must be addressed in a more constructive and scientific fashion than they have been in the past.