Story and photos by Susan Maxwell Skinner
Biologist Mollie Ogaz steadies an inflatable craft as partner Mitch Gladding takes oxygen readings below Nimbus Dam. Photo by Susan Maxwell Skinner.
SACRAMENTO REGION, CA (MPG) – A year-round survey is keeping tabs on oxygen levels in the American River.
Operating with Sacramento Water Forum funding since 2022, the project measures dissolved oxygen from below the Folsom Dam to Nimbus Basin; surveys also extend to Fair Oaks and Watt Avenue reaches.
Although dissolved oxygen levels are critical to all river health, research is particularly supportive to Chinook salmon reproduction.
Teams of biologists engage in daily readings. This reporter accompanied them on a recent river outing.
A critical salmonid spawning habitat lies below Nimbus Dam. Here, shallow gravel beds challenge data-gathering.
Biologist Mitch Gladding uses an oxygen-measuring device in Nimbus Basin. Photo by Susan Maxwell Skinner.
Carefully avoiding teeming Chinook, Cramer Fish Sciences staffers drag an inflatable craft through channel riffles.
“We watch where we’re walking” said Biologist Mollie Ogaz. “The salmon redds (nests) are easy to see — if you know what to look for.”
Oxygen sensors trail in the biologists’ wake. Ideally, dissolved oxygen should measure more than 7 milligrams per liter – or about 70 percent of water content.
“If oxygen falls below that level, salmon can become stressed,” said Water Forum Program Manager Erica Bishop. “We don’t want these Chinook adults to die before they spawn. Egg and fry development also suffers if water conditions are not sustained.”
Continue reading the full story in the Carmichael Times here.