That would be a problem if they had "too many" fish come back. That would also mean that the salmon aren't being eaten by the target predators.

But, given the water supplies and temperatures in WB I think they would annually need to import eggs (water too warm to hold adults from arrival to spawning) which would mean (for example) that the Kalama would have to be managed for WB egg needs. I don't think that plane would even get off the ground.