SACRAMENTO (AP) — Flooded rice fields appear capable of serving as substitutes for now-depleted wetlands and helping California's Chinook salmon population recover, researchers have concluded.
In a report submitted to the U.S. Bureau of Reclamation, the researchers said salmon raised in replicated rice fields near Sacramento as part of their experiments were the fattest and fastest-growing salmon ever documented in freshwater in the state.
"We're finding that land managers and regulatory agencies can use these agricultural fields to mimic natural processes," study co-author Carson Jeffries, field and laboratory director of the University of California, Davis' Center for Watershed Sciences, said in a news release on Thursday.
The state Department of Water Resources and a nonprofit called California Trout also participated in the report, which is dated Oct. 1.
Juvenile Chinook salmon in California's Central Valley have traditionally been reared in wetlands, where they fatten up before heading off to the ocean. A salmon's size is an indicator of its likelihood of returning to spawn as an adult, according to the study.
The goal of the researchers' experiment was to determine whether rice fields flooded between harvests could stand in for the wetlands that once filled the area.
In February, they introduced thousands of juvenile Chinook salmon into replicated rice fields built in the Yolo Bypass, a flood plain outside Sacramento.
Three types of rice fields were tested, with researchers concluding that the fish did not show a preference for one in particular.
High densities of zooplankton that the juvenile salmon feed on were found in all three types of fields, according to the study.
"This is a win-win model that can be replicated around the state," said the study's lead author, Jacob Katz, a biologist with California Trout.