Barging the hatchery production, which this likely was, would be a good way to wipe out the wild stock. Reduce the prey base but keep the predators. Work as well as reducing hatchery plants but still fishing at the same rates. Besides, it would crash the Big C fisheries for walleye and smallies.

If you are trying to protect a few stocks, this might work. For example, I worked a smolt trap that we operated from March to June. Smolts were moving the whole time and we know we had smolts two weeks earlier than that because they were big enough to be caught in the adult trap. First year we had smolts into early July. It would be prohibitively expensive to collect a river's smolts far enough upstream to make a survival difference and transport them downstream past the predators.

If the decision is made to forego wild production, then collect and transport at each hatchery. One cheape option, which some folks looked at, was actually to construct a pipeline into which you paced the smolts and sent them downstream. That would work, until the hit the outhitting of the pipe but they would likely overwhelm most of the predators.