Nothing you can do about it. People cause the problems and many parts of the world will continue to see huge population growth including the US which growth is coming from massive quantities of immigrants.
If there on a fall spawning run then I would think you would want the season closed . Let them do there thing . It could be that it should of been closed sooner back 30 years ago to keep the fisherman away from the spawning fish and you guys were lucking out by taking advantage early spawners .
I should like to point out that although they are on their "spawning run", they dont actually spawn until November. What I'm saying is that we would like to fish the initiall beginnings of the run which i am saying doesnt occur now until the end of Sept. when historically it occurred in early Sept. I noticed you are holding a bass... What you are saying is that Salmonid fishermen shouldnt enjoy the early stages of the spawn yet if you were to propose to Bass fishermen that they close May, June and July during the early, actual spawn and late stages of Bass spawn, I'm sure there would be an uproar. Bass fishermen and Salmonid fishermen all practice catch and release without a measurable detrimental effect on spawning, as a matter of fact, despite fishing pressure, bass procreate at alarming rates when introduced to new bodies of water.
While I'll have to think about this some more I don't necessarily disagree with you. That said, you referenced bass fishing during the spawn and then river fishing for spawning cold water fish. One of the primary differences I see is wading vs. boating and wonder if a wading fisherman would disturb the redd more so than a floating? I do not know the answer, just spitballing.