In the past, most of the fish that survived to adulthood spawned. In years of poor ocean conditions, at least some of them made it back. In good years, even more did.

What we do now is knock the run down a little on bad years and a lot on good years. This gets complicated by our desire to fish Chinook and coho before we have any idea of the run.

And, what do we do with ocean fisheries? The last few years we model a season. Then, when catches don't materialize we increase the limits and days fished.

Ocean "conditions" are pretty variable, too. Some Oregon researchers came up with a great model to describe OR coho. Used 4 separate ocean measures to explain survival. The problem was that the 4 factors were not necessarily related. The first 3 could be good but when the 4th came in it was bad; hence a low run. The reverse happened, too. It looks like good and bad things can happen over the whole marine time; any one can kill the run and any one can bring a good return.