Thursday, January 26, 2012

Recent Snowfall Bodes Well for Columbia Salmon

During the last ten years returns of ESA listed salmon and steelhead Columbia and Snake River systems have experienced a period of relative abundance. Many have attributed the improvements to court mandated spill, or productive ocean conditions, both of which are undoubtedly contributing to improved survival. But another factor that cannot be underestimated is the importance of a healthy snow pack which transports outmigrating juveniles to sea during spring runoff. Several recent years in the Columbia basin have seen robust snow packs and not surprisingly the survival of outmigrating juveniles through the hydrosystem has been better than usual. The rate at which fish pass through the system limits their survival, and when high runoff keeps river temperatures cool, fish experience less metabolic stress and predation by invasive warm water fish is kept to a minimum.

That's why there had been some concern until recently that this winter's La Nina had yet to deliver it's promised, wintry punch. Fast forward two weeks and the situation looks very different. After the latest round of winter storms the snow water equivalent packed in the mountains of the interior Columbia Basin jumped almost 10%, and with more rainfall yet to come there is hope that this years runoff could be more than adequate to safely pass another generation of juveniles to the ocean.

More in the Columbia Basin Bulletin:

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