Fishways in Australia: Past Problems, Present Successes and Future Opportunities
Australia, baffles, barriers, behavior, channel, denil, environmental impact, fish ladder, fish locks, fish pumps, habitat, impact of dams, instream flow, life cycle, mathematical models, migration, pool, pool type, pumps, salmon, spawning, streams, survival, swimming, swimming speeds, weir
Journal or Book Title
A major environmental impact of dams and weirs throughout the world is the prevention of fish migration. To ameliorate this impact and aid fish migration, fishways or 'fish ladders' have frequently been built. Fishways are generally a channel divided into pools by baffles, and fish ascend by swimming from pool to pool. In addition to the common pool-type fishways, there are Denil fishways, fish locks, fish pumps, fish gondolas and trap-and-transport facilities. Most of the fishways throughout the world have been built in the northern hemisphere, and almost all of these have been designed for salmonid fish species. The spectacular migrations of salmon are well-known. While the migrations of native Australian fishes are less spectacular and less well-known, they are just as critical for the survival of these fish. In south-eastern Australia over 40% of the fish species are migratory, i.e. they make large-scale movements that are essential for the completion of their life cycle. These fish include popular angling species, important commercial species, and some species of high conservation value. These fish migrate to breed, to disperse into habitat, to disperse from spawning grounds, and to disperse from refuges following drought. Thus, free movement along streams is an essential part of their behaviour and habitat needs. The majority of our freshwater fish have declined in abundance and distribution within the last 100 years and many researchers have identified barriers to migration of fish as a major contributing factor in these declines.