Growing Stream-flow Variability Threatens Chinook Salmon Spawning in Pacific Northwest

By Garry Rogers @Garry_Rogers

GarryRogers:

Increasing extremes are expected, but the prospects are sad nevertheless.

Originally posted on Summit County Citizens Voice:

Research documents more fall and winter flooding

Staff Report

FRISCO — Threatened Chinook salmon have been able to adapt to many changes over millennia, but climate change presents a big new threat, as many rivers around Puget Sound have seen bigger fluctuations in stream flows during the past 60 years.

“There’s more flooding in late fall and winter,” said Eric Ward, an ecologist at NOAA Fisheries’ Northwest Fisheries Science Center. “This is happening when the eggs are in the gravel or when the juveniles are most susceptible.”

More pronounced fluctuations in flow can scour away salmon eggs and exhaust young fish, especially when lower flows force adult fish to lay eggs in more exposed areas in the center of the channel.

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