juvenile fish bypass, U. S. Army Corps of Engineers from Wikimedia Commons:
http://commons.wikimedia.org/wiki/File:Juvenile_fish_bypass.jpg
Dictionary of Ichthyology
bypass systems = moving screens lowered into turbine intakes to divert fish away from turbines at hydroelectric dams. Bypassed fish can then be returned directly to the river below the dam. In some cases facilities exist to load bypassed fish onto barges or trucks for transport to a release site downstream from all dams in a series.
