I am not sure how that works for fish that only spawn once a year. I know that bluegill grow larger up north because they don't use up so much energy on spawning. But they are probably unique because they spawn all the time as long as the water is the right temp.
As long as you have established population of LMB, I guess there is no harm in providing spawning habitat. But how do you provide spawning habitat for a trophy catfish? Tractor tires?
