[_Microft]

Do you maybe mean something like a fish ladder?

https://en.wikipedia.org/wiki/Fish_ladder

[Zababa]

Or the cool "Salmon cannon" https://www.youtube.com/watch?v=2z3ZyGlqUkA

[OJFord]

Am I seeing that right, they have a guy stand there, pick fish up, and load them in to a pressurised cannon?

I wad expecting something a bit more sophisticated/under the fish's control, even given the name!

[robocat]

They also have an automated system: https://www.youtube.com/watch?v=eGzdOpCisnQ

[ambicapter]

Can all fish jump? Feels like it may be something that salmon are pretty good at, but a gigantic fish may not.

[_Microft]

Jumping is not always necessary. You can get an idea of possible designs for fish ladders from the photographs in the section "Types" in the article.