fish lock

A fish pass, also known as a fish ladder or fish lift, is a structure designed to help fish migrate upstream over or around a dam. These passes are crucial for maintaining fish populations, especially for species like salmon that need to reach their spawning grounds.123

Fish ladders typically consist of a series of stepped pools, allowing fish to move gradually over changes in water level. A fish lock, on the other hand, operates more like a ship lock, using intermittent filling and emptying to raise fish chamber by chamber. While these technologies have seen success in some areas, the increasing number of dams has led to significant declines in migrating fish populations in others.123