The problem with Ricker is that it is an economic analysis rather than biological. What is the minimum investment in spawners to get the maximum catch? Completely ignores any sort of inter species effects.

In AK, wild coho are fished at 60% (at least in the particular SE AK stream I am familiar with). The catch has varied from 1,000 to 8,000, with the appropriate escapement. It is sustainable at any of those levels.

What changed the catch? Pinks. No pink spawners, 1,000 coho catch. Approximately 2 kilos of pinks per square metre and you harvest 8,000. That number of pinks, at the higher levels, certainly exceeds an MSY calculation for the stock.

That is a nice, but simplistic, way to look at it. The downside of the large pink escapements is that they appear to depress Chinook survival and may outcompete coho in the ocean.

Recovery is going to take looking at the whole ecosystem, and this will include the invertebrates that feed to fry and smolts, including the predators like pinnipeds, terns, and cormorants. Doing it within dozens of silos will guarantee non-success.