Editing Fish ladder (section)

{{short description|Structure to allow fish to migrate upriver around barriers}}
{{Lead too short|date=April 2024}}
[[File:Bonneville Ladder.jpg|thumb|right|300px|Pool-and-weir fish ladder at [[Bonneville Dam]] on the [[Columbia River]]]]
[[File:Vetla paisjärv, Jägala.webm|thumb|Drone video of a fish way in Estonia, on the river Jägala]]
[[File:Ferc-fish ladder.svg|thumb|right|upright|[[Federal Energy Regulatory Commission|FERC]] fish ladder safety sign]]

A '''fish ladder''', also known as a '''fishway''', '''fish pass''', '''fish steps''', or '''fish cannon''', is a structure on or around artificial and natural barriers (such as [[dam]]s, [[Lock (water transport)|locks]] and [[waterfall]]s) to facilitate [[Fish migration#Classification|diadromous]] fishes' natural [[Fish migration|migration]] as well as movements of [[Fish migration#Classification|potamodromous]] species.<ref name="whatis">{{cite web|url=http://www.michigan.gov/dnr/0,4570,7-153-10364_52259_19092-46291--,00.html|title=What is a Fish Ladder?|publisher=[[Michigan Department of Natural Resources]]|access-date=27 April 2012|location=Michigan}}</ref> Most fishways enable fish to pass around the barriers by swimming and leaping up a series of relatively low steps (hence the term ''[[ladder]]'') into the waters on the other side. The velocity of water falling over the steps has to be great enough to attract the fish to the ladder, but it cannot be so great that it washes fish back downstream or exhausts them to the point of inability to continue their journey upriver.