There’s not a real hard fast rule about which fish should be kept versus released.
For those who keep limits of 14-15 inch walleyes, please realize that virtually no female fish in this size range have spawned. In order to ensure that each female from a year class has had an opportunity to spawn at least once, you really need to wait until their 19 inchers. Pounding 14-15 inch fish BEFORE they’ve reached spawning size can have some pretty horrible effects (the argument against slots).
The legal fish argument needs to stop. I could go out and keep 6 fish of any size every single day and be within the law. But if enough people do that, the fishery suffers and everyone gets screwed. I also think most of these catch and kill fisherman have an illegal amount in their freezer, or give away fillets which we all probably do, but is also illegal.
People complain about Indian netting and cormorants, but don’t bother changing their own habits. If you want to be able to keep a limit of 6 occasionally, you better be doing your part and limiting yourself to 3 most other days, otherwise the government eventually will.
Saugers are different than walleyes in how their biomass is distributed. I don’t think you run into the problem of female fish being taken out prior to hitting spawning years. I don’t see the need to keep a fish that has been sitting in the river for 8 years, but I won’t lose sleep if someone does. I’m more concerned with the guys that go day after day and keep limit after limit of any size.