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Preseason Salmon Forecast 2012?

Now that all Spring & summer Salmon fishing is over what happened to the preseason forecasts for the Snake River returns? Most are similiar to this from the Northwest Power & Conservation Council. "The 2012 forecast is 314,200fish entering the Columbia — 168,000 Snake River fish (39,100 wild) and 32,600 upper Columbia spring Chinook (2,800 wild), with the remainder of the run returning to mid-Columbia tributaries. That’s nearly 100,000 more than the 2011 run of 221,200.

Answer

Pre-season we predicted that about 118,000 adult soring/summer Chinook salmon would return to the Snake River basin above Lower Granite Dam in 2012. About 80,000 or about 68% of the pre-season forecast actually returned. While Columbia River fisheries may have caught proportionately slightly more Snake river fish this year than in previous years the vast majority of the diference between forecasted and actual returns is attributable to forecasting error. Fisheries biologists have been struggling for well over a century to find measures of ocean productivity that could be used to predict marine survival of juvenile and immature adult salmon. While we do have some varibales that seem to work in some climate regimes, they fail in others so ideal forecast variables have yet to be discovered.