Oh if it were so simple, maybe we could weed through the politics, as well. Survival can be divided into a number of significant periods.

-Survival of egg deposition to hatch. This can be particularly significant in degraded streams that suffer from overlogging, siltation, ag runoff.

-Survival from fry to smolt. This is important in the Columbia since the many dams create passage hazards, slow flows, and increased predation during outmigration. For the past decade, substantial barging programs have been conducted in an attempt to mitigate this problem.

-Ocean survival. This is the great unknown that scientists and managers do not have a good handle on. Its been documented that EL Nino/La Nina events lower ocean survival. Its also been documented that a longer term, 20-30 year climatic event, also affects survival. There's good evidence to suggest that we are now heading into that part of the cycle which favors ocean survival in the Pacific Northwest, while decreasing survival in Alaskan waters. But because the mechanism is not known, all scientists can record is actual survival, not whats causing it.

Now look at the numbers. The average salmon can spawn 800 (sockeye)to >5000 (king) eggs/female and a good run (like this years springer run on the Columbia) can be in excess of 100,000 fish. Thats 250,000,000 eggs at the high end. With the shear numbers of potential fish, a fraction of a percentage point in survival can make a tremendous difference in run size.

Good ocean conditions can more than make up for poor survival across dams. But string together poor smolt survival and poor ocean survival, over a several year period, and your bumping up against extinction. Runs can lose an order of magnitude of returning adults with each successive generation that endures all around poor conditions.

This is perfectly normal for salmon. It allows the fish to rebound from a very small run to their original numbers in just a few generations. In this way salmon can survive flood years, poor ocean condition years, slides and avalanches that re-route streams, etc. The problem we have is the constant year after year after year stress that we put on the fish, whether it be over fishing, dams, logging, agro, etc. Humans put relentless obstacles in front of all of the important survival periods of salmon.

The best thing we can do is to enhance all phases of survival that we can, knowing that there is nothing we can do about ocean survival. The worst thing we can do is to allow a large year class to tell us that there is no problem.

[This message has been edited by obsessed (edited 07-07-2000).]

[This message has been edited by obsessed (edited 07-07-2000).]