There is some interesting data out of AK dealing with pinks and coho. AK fishes wild coho at 60% and it seems, over a decade or two, to be "sustainable". Their pinks fluctuate. When the crik had no pinks, the coho harvest was 1,000. When they had 2 kg of pinks per square metre the harvest was 5-8000. We, down here in WA, have simply decided to keep our runs at the low end of production by limiting escapement.

In a similar vein, modeling fo AK coho showed that a 40% HR gave more harvest than 60% because of the fertilizer effect of the added spawners.

The information is out there, but would require short term reductions for long term gain.