Fish ladders and fish cannons

Fish ladders give fish an alternative way to get through dams, which often block fish migration routes.

Salmon jumping up fish ladder
https://www.youtube.com/watch?v=uqR2g8darqs

How Fish ladders work - Science Man
https://www.youtube.com/watch?v=sabk7Khq0kQ

New Thompson Falls Dam fish ladder
https://www.youtube.com/watch?v=_bISGOvNLhk

Fish cannons in Washington State
https://www.youtube.com/watch?v=fn6_6N_KDYw