From a fish-eye view, rice fields in California's Yolo Bypass provide an all-you-can-eat bug buffet for juvenile salmon seeking nourishment on their journey to the sea. That's according to a new report detailing the scientific findings of an experiment that planted fish in harvested rice fields earlier this year, resulting in the fattest, fastest-growing salmon on record in the state's rivers.
The report, provided to the U.S. Bureau of Reclamation, describes three concurrent studies from researchers at the University of California, Davis, nonprofit California Trout and the California Department of Water Resources. The scientists investigated whether rice fields on the floodplain of Yolo Bypass could be managed to help recover California's populations of Chinook salmon, and if so, the ideal habitats and management approaches that could allow both fish and farms to thrive.
"We're finding that land managers and regulatory agencies can use these agricultural fields to mimic natural processes," said co-author Carson Jeffres, field and laboratory director of the Center for Watershed Sciences at UC Davis. "We still have some things to learn, but this report is a big step in understanding that."
Researchers found that the fish did not have a preference among the three rice field types tested: stubble, plowed and fallow. The food supply was so plentiful that salmon had high growth rates across habitats and management methods.
"It's like a dehydrated food web," said Jeffres of the harvested rice fields. "Just add water. All of those habitats are very productive for fish."
The salmon did demonstrate a preference for habitats with better water flow. Jeffres compared it to choosing among three good restaurants: Each offers good food with hearty portions, but one has better ambience and so is chosen above the others. In this case, the better water flow was the ambience the fish preferred.
|Contact: Carson Jeffres|
University of California - Davis