I keep beating the very dead horse that Oregon had a great analysis of OPI coho. It used four temporally and spatially separate but consecutive variables to account for marine survival.

The problem was that any one could overshadow the other 3. So, 3 "goods" with #4 being bad and the return is down. Or, the last one is really good and takes a disaster and makes it a good run.

That is the primary problem of our need to have ocean mixed stock harvests. We fish on a black hole and hope we're close. Faith Based Management at its finest.