12/8/11
The chances of salmon spawn traveling through the Humboldt Bay Wildlife Refuge and making it out to sea has now improved with a recently completed restoration project.
When the refuge began exploring the idea of restoring the area's Salmon Creek 10 years ago, salmon were getting into the creek, but instead of leaving when they were grown, the creek's man-altered channel was sending them back into the creek.
”That's really challenging,” refuge manager Eric Nelson said. “Obviously, there are a lot of factors and reasons why fish populations are depleting -- fishing offshore, climate change, activities happening upstream -- still, the best answer is to restore habitat.”
He said further scientific data pointed to habitat loss as the No. 1 reason for coho salmon disappearing. Nelson said the creek is also a habitat for steelhead and chinook, as well as lamprey and the red-legged frog.
Since the project's completion, the Department of Fish and Game has also identified steelhead smolt, tidewater goby and several adult salmonids -- which includes salmon or trout -- in the restoration area. The department has installed a pit tag reader on the creek to help monitor habitat use by salmonids over time.
Before the refuge took on the project, the creek's wetlands had been diked and turned into a pasture. Farro said the creek was a straight line channel before the restoration work.
Principal design engineer Mike Love said the project restored the stream's path by referencing an 1860s map and aerials. As the work began and trenches were dug, there were areas where clay turned into sand, which helped identify the water's original path, Love said.
In addition to the restored path, the design called for young willow trees to be planted and large structures added to the water to provide cover and food for developing salmon. The structures mimic historic conditions, when sloughs, channels, marsh and mudflats were covered with large rootwads and log jams.
Nelson said these elements are often missing from habitats now because bridges and culverts block the paths of trees going downstream.
Salmon need a protective habitat where they can live and feed for a year in order to grow into an appropriate size.
”It's kind of a neat thing to rebuild a creek,” Nelson said. “It's hard, you don't know what you're going to run into ... it's a good feeling to restore this habitat. We can't make it as diverse as it used to be, but it can develop into that.”
