US fish guidance system will improve the survival of downstream-migrating fish

摘要

Many fish species that migrate between freshwater rivers and the ocean such as salmon, shad, herring and eels are in danger of extinction throughout some or all of their range. The impacts on these populations include: loss of habitat; over fishing; and, poor passage conditions at dams. State and federal laws now mandate protection of these and other fish populations. Dam operators must often implement expensive modifications at the dams or spill large volumes of water to pass juvenile fish downstream past dams safely.