Record Fall Chinook Run Occurring
by Ken Schlichte
The Pacific Decadal Oscillation created cool ocean conditions and favorable ocean salmon habitat conditions in 2008 and 2009 (shown below in Figure 2 from the Northwest Fisheries Science Center) that have resulted in 2010’s large Columbia River Spring Chinook run and are now resulting in an even larger 2010 Columbia River Fall Chinook run.
Figure 2. Time series of shifts in sign of the Pacific Decadal Oscillation (PDO), 1925 to 2009. Values are averaged over the months of May through September. Red bars indicate positive (warm) years; blue bars negative (cool) years. Note that 2008 was the most negative since 1956.
This year’s Fall Chinook passage at Bonneville has already surpassed 2009 and the run has not even peaked yet.