If the desired "harvest" is, say 20% then take 20% every day of that day's passage. Taking fish out of the whole run allows the retention of all segments of the run.

Front-loading steelhead fisheries has resulted in the loss of that segment of the runs, and they don't seem to be doing too well without it.

The benefit of traps or fishwheels is that we can safely release the wild fish. But, in some place like the Columbia, each hatchery run would have to differentially marked in order to take the "right" fish.

Unrestricted intensive removal of even the hatchery fish in a mixed stock "fishery" at a trap or fishwheel would give us the same result as we see in the wild stocks; some will get overfished.

What use is a hatchery if we don't allow sufficent escapement to each of them.

It all gets back to fishing where we know what the stock composition and abundance is, in a real-time way.