Salmon will swim towards turbulence (as part of a simple navigational strategy) so you can get them to swim into something using that. However, as with fish lad

Salmon will swim towards turbulence (as part of a simple navigational strategy) so you can get them to swim into something using that. However, as with fish ladders, I expect it isn't 100% effective. Source: my dad has built some fish hatchery equipment including volitional entry devices.