You can read about the conclusion of another successful year of salmon fish fattening on Knaggs Ranch rice fields on this San Francisco Chronicle cover story. Or…
Once upon a time the California native salmon population was dwindling. Every year the fish hatcheries would release hundreds of thousands of salmon to have a miniscule return because the river was so channelized that the fish could not find the important floodplain habitat where they need to put on weight and delay their migration to sea to a time when the upwelling off the coast of San Francisco provides food.
Then one day a Department of Water Resources scientist Ted Sommers had an idea. He placed a 100,000 tagged hatchery fish in the main stem of the Sacramento River and 100,000 tagged hatchery fish in the Toe Drain of the Yolo Bypass (a flood control area that can still operate like a floodplain). He caught 16 fish in the Bay trawls at the end of a few weeks and the Bypass fish were noticeably bigger. And then Carson Jeffres, a grad student at UC Davis decided to build off of this with an experiment on one of the few remaining undammed rivers in NorCal. He created an experiment on the Cosumnes River, which resulted in the now “famous” cooler picture of floodplain salmon three times the size of the other salmon. This resulted in the National Marine Fisheries Service requiring 17,000 acres of floodplain habitat in the Sutter and Yolo Bypasses as part of the Biological Opinions for the water agencies to continue pumping water through the Delta.
In some ways this seemed like an “all is lost” moment because the agencies interpreted that as flooding the Bypasses wall-to-wall for long periods of time and this would have made it tough for the farmers and duck clubs in the Bypass to survive and then this would have compromised the Bypasses as a flood control structure. Until one day John Brennan, a farm manager/appraiser/rice drier owner put together a group to buy Knaggs Ranch and experiment with using rice fields as surrogate salmon floodplain habitat. And now 3 years later the experiment has proven that the rice fields with water held for up to 6 weeks create “Floodplain Fatties”. And a coalition of farmers, scientists, fish advocates, county folks, wildlife area managers, and agencies are proposing a management system that is compatible with all of the existing uses in the Yolo Bypass. This year is a drought year and naturally really tough on fish. Access to the floodplain will give them resiliency to survive this kind of water year and in the future sea-level rise and warmer temps. It is also Conservation Measure 2 in the Bay Delta Conservation Plan.