Flooding California rice fields in the Yolo bypass provides a "bug-buffet" for young salmon on their way to the ocean, causing rapid growth rates.
A report by the U.S. Bureau of Reclamation described three studies that looked at whether planting rice fields on the floodplain of the Yolo bypass could help recover populations of chinook salmon, a UC Davis news release reported.
"We're finding that land managers and regulatory agencies can use these agricultural fields to mimic natural processes," co-author Carson Jeffres, field and laboratory director of the Center for Watershed Sciences at UC Davis, said. "We still have some things to learn, but this report is a big step in understanding that."
The researchers found the fields caused the salmons' food supply to be so bountiful it caused them to have high growth rates.
"It's like a dehydrated food web," Jeffres said. "Just add water. All of those habitats are very productive for fish."
The salmon did not have a preference among stubble, plowed or fallow fields, but they did prefer habitats with better water flow.
Jeffres said it was like choosing between "three good restaurants." All have a good food selection but one has better "ambiance."
During the experimental flooding the fish's' average growth rates were the highest recorded in California fresh water. The mortality rate was higher than the last time the experiment was conducted in 2012, but that may have had to do with a dry spell that drew more predatory birds to the area.
"These results are good news for the effort to rebuild salmon populations in California," lead author Jacob Katz, a biologist with California Trout, said. "We've always suspected that when we mimic natural flood processes in agricultural fields, we give these fish a food-rich habitat they recognize and thrive in. These findings support that theory and provide a strong path forward for California land-use planners, conservationists and farmers alike. This is a win-win model that can be replicated around the state."
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