Dave -
If one is interested in have as long as seasons as possible or removing (keeping) as many hatchrey fish as possible wild release (even ocean coho) always makes sense. Remember the evaluation will always be based on the "fleet's" impacts rather than individuals.

Maybe an hypothical example might help. Let's assume that the coho population is 1/2 wild and 1/2 wild and the fleet is averaging a 1/4 of a hatchery coho/angler landed (wild coho released). That would mean that if a 1,000 anglers were fishing they would have landed 250 hatchery coho while releasing 250 wild coho. If the anglers were allowed to keep wild coho they would have also killed 250 wild coho (we'll ignore the complication of limits to keep things simple).

In releaseing those 250 wild coho they would kill 50 if the release mortality was 20%. Even if that mortality were 80% they would kill 200 fish (still less than 250).

As we all know for the never ending CCA/selective fishing debates in this day of ESA listed fish our fishing seasons are limited by impacts on those listed fish. Sticking with the above example let's say that the fishery will be limited by a total wild impact (dead fish) of 2,500. Without selective fishing that would mean those 1000 anglers at 250 wild coho per day that allowable impacts would be reached in 10 days of fishing. However if that mortality were say 50% then that fleet in our example would be killing 125/day and they would be allowed to fish 20 days until they reached the allowable impacts limit of 2,500.

So the question to you would be does it make sense to release those wild coho to have seasons that were substantially longer?

Tight lines
Curt