by Terry Flores
The premise in "Getting past the dams" is simply wrong [Opinion, Jan. 24]. Salmon and steelhead trout survival is far more complex than mandating spills at dams.
According to the latest NOAA Science Center research, fish survivals since 2006 have varied dramatically even though the spill program has remained static. Nor can NOAA correlate spill with increased adult returns.
As correctly noted, there are many elements affecting fish throughout their complex life-cycle including ocean conditions, which can swamp human actions taken at the dams. These fish live for four to five years, travel thousands of miles, face predators everywhere, face an often hostile ocean environment, and run a gauntlet of nets and hooks to spawn and sustain their genetic legacy.
But, spilling water does not affect survival of fish passing through turbines and doesn't change water temperatures because it neither warms nor cools water being spilled. Spill does interfere with barging that benefits fish when water temperatures are warm and predation is high and has kept returning adult fish from being able to use the fish ladders.
The Fish Passage Center information you relied on in your editorial does not provide a complete or accurate picture of factors affecting healthy salmon-runs.
Factors affecting sockeye salmon returns to the Columbia River in 2008, Northwest Fisheries Science Center, 2/09
Table 5. Estimated outmigration of sockeye salmon smolts from the Sawtooth Basin in Idaho
and adult returns passing Lower Granite Dam. Last two columns added by bluefish.
Out-migration Year Estimated Sockeye Juveniles Adult Return Year Adults Passing Lower Granite Dam Index SAR (%) Adults Arriving in Stanley Basin Index SAR (%) 1998 96,669 2000 299 0.31 257 0.26 1999 24,664 2001 36 0.15 26 0.10 2000 5,298 2002 55 1.04 22 0.42 2001 7,356 2003 14 0.19 3 0.04 2002 16,958 2004 113 0.67 27 0.16 2003 9,603 2005 18 0.19 6 0.06 2004 9,749 2006 15 0.15 4 0.04 2005 68,855 2007 46 0.07 4 0.01 2006 109,779 2008 805 0.73 636 0.58 2007 88,398 2009 838 0.95
Note: Last two columns added by bluefish. NW Science Center may be changing the Column 5, Index SAR, as they have recently learned of some errors in the assumptions regarding column 2, Estimated Sockeye Juvenile data.
bluefish notes: a SAR of 2.0% is considered the minimum necessary for a self-sustaining Sockeye poplulation.
Report Conclusion: In summary, the results discussed here provide a consistent pattern to explain the large return of adult sockeye to the Columbia River in 2008. Based on these results, we conclude that the factors responsible for the high return largely acted on fish downstream of Bonneville Dam and during the marine component of their life cycle, and not in the river upstream of Bonneville Dam.
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