Fish ladders: are these fins really made for climbing?
When someone mentions the words “fish ladders”, do you think of a tangy salmon or sturgeon sneaking up an inclined rung? While the term conjures up some entertaining visions from our gill-wearing friends climbing a simulated series of steps, fish steps are actually constructed for the purpose of maintaining a fishery.
Diversion routes for the migration of fish
The answer to the question: “Are these fins really made for climbing?” is no, but fish use fish ladders as diversion routes when a river system presents a specific obstacle. Passages, dams and waterfalls are three examples of river obstacles that can hinder fish migration … and ultimately lead to a decline in fish populations.
Many anadromous (I know fancy) spawning fish depend on migrations up and down rivers – species like salmon, sturgeon, and shadow. While downstream migration generally occurs in the early stages of life, upstream migration occurs after anadromous species have reached adulthood.
Designing fish steps
The designs of the fish lanes may vary depending on the type of obstruction, river flow, and type of fish, but the purpose is the same for all fish ladders. Each ladder contains a series of ascending pools that can be reached when fish swim against a jet of water. In other words, fish jump through the rushing water, rest in a pool, and repeat this process until they reach the “top” of the ladder.
The funny thing is that once the fish are up there they no longer need to fix a ceiling fan or touch up the walls with a fresh coat of paint. They just keep swimming on their anadromous (I really like to use this word) migration route for survival and conservation.
When you buy a fishing license, you are contributing to conservation projects such as building fish steps that will help preserve our waterways for future generations.