Pretty simple. Say you have one egg that produces one more egg every day. One man takes one egg every day and cooks it, therefore he has an endless supply of 1 egg a day going forward. Now if a second man also does this, after one day neither will have any more eggs.
Is the lack of eggs any more the result of the second man than the first?
Simply because you used a resource first, does not mean it is only on the new party that the resource is running low. Adding an extra pressure onto the lake may have been the reason the lakes ran dry, but the solution may be each party has to sacrifice instead of one party should get no rights at all. The natives claim to the fishery is as strong as yours (strictly legally speaking, stronger). We offered natives fishing rights at their own terms in the treaties that served as payment for the land the state sits on. Whether you (or me) disagree with that is irrelevant, it is the law.
I think we need to focus on management solutions within the context of these laws instead of trying to work around a treaty we, as a state, clearly agreed to!
Could go on forever so I will leave the thread alone with that post, i think my position is pretty clear. feel free to disagree