It’s been just over three months since our salmon rearing habitat structures were placed in the Sacramento River downstream of the South Bonnyview Bridge near Redding, California. We have been anxious to revisit the structures in situ to find out just how much they are being used by the juvenile salmon. The scope of the project includes periodical underwater surveys to monitor the structures, and on August 16, 2017 the initial sonar camera footage was taken by Dave Vogel of Natural Resource Scentists, Inc. What this footage reveals is very exciting.
In the above video, the river is flowing from the left to the right. River depth is 12 feet and water clarity is only several feet. The distance in feet from the sonar camera lens is shown on both sides of the imagery. A school of salmon fry can be seen swimming on the downstream side of the shelter.
“I am happy to report that juvenile salmon appear to be attracted to the structures like magnets,” says Dave Vogel. “Some of the structures in even deeper water (e.g., 20 feet) revealed even larger numbers of salmon.”
As with any pilot project, the structures and their placement was ultimately an experiment. For all of the science, research, engineering, and design that went into them, until installation, it was only hypothetically that they would work. Now, with this footage, we have confirmation: Juvenile salmon utilize the rearing structures! This is excellent news and inspires us to do more projects like this.