If the Indians are doing the same as what the white settlers did to the salmon runs like you suggest they are, they'd have been wiped out long ago.
I don't remember the years now but it wasn't long at all and the settlers had decimated the runs. It wasn't farming, logging, dams, or Indians that killed the Columbia salmon it was greedy uneducated settlers that did it, long before the other factors came into play. When I say uneducated I'm referring to the fact that they didn't know any different. Not all would have fished like they did if they knew the impact, but I'm sure some would just like the commercials today do.