The (Everett) Herald reports:
Struggling salmon populations in south Snohomish County took a beating last week when normally tranquil streams such as North Creek and Little Bear Creek filled to overflowing, biologists said.
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Salmon redds often are buried under cobbles and rocks in faster-moving sections of streams, (Ralph Svrjcek, water quality specialist with the state Department of Ecology) said. That helps protect them from strong flows and also exposes them to water with high oxygen content. If the water moves too fast, however, even the bigger pieces of gravel get washed downstream.
“When the bigger rocks go, salmon eggs say, ‘I’m going with the flow, I’m gone,’ ” Svrjcek said.
Along with the pebbles and gravel, major amounts of sediment are washed into the water column, Svrjcek said. That silt can choke salmon redds.
Survey crews already were out assessing salmon redd damage as the streams recovered from last week’s storms, said Darren Friedel, a spokesman for the Washington Department of Fish and Wildlife.
Still, little is known about how the eggs fared. A better picture will emerge when any surviving young fish migrate out to Puget Sound this spring. The state will do migration surveys at that time, Friedel said.
The real impact won’t be known until the still-unhatched salmon return as adults to mate several years from now, he said.
“We do know these flood events can scour river channels, washing away salmon eggs and also affect salmon rearing in the streams,” Friedel said.
