Young Salmon Get Boost in Delta Rice Fields
Fish scientists and farmers are coming together at a handful of rice fields outside of Sacramento, where a key salmon habitat study is underway.
Farmer John Brennan produces rice on his 20 acres during the summer. This winter, the area is also home to 50,000 two-inch salmon.
“We don’t refer to them as rice fields,” Brennan says, “we only refer to them as surrogate wetlands.”
Brennan’s fields are in the historic floodplain of the Sacramento River, where winter flows once overtopped the riverbank and inundated hundreds of acres. Through water infrastructure projects and flood control, the river’s natural patterns have been greatly altered.
“Fish grow much better when they’re on the floodplain, where they’re on the habitats that adjoin the river rather than in the river itself,” says says Jacob Katz of the non-profit California Trout.
The slow-moving waters on a floodplain provide shelter for young salmon and a rich food source. That allows them to grow bigger and faster, increasing their chances of surviving as they migrate to the ocean and run the gauntlet of predators.
Katz and UC Davis scientists are studying these rice fields to see if they mimic wetlands, extending a pilot project from last year. Young salmon are tagged as they’re released into the fields, which are flooded between rice crops. Last year's salmon grew bigger and healthier.
“Fish put onto these rice fields grow at phenomenal rates,” Katz says. “What we’re seeing is what a Central Valley salmon actually should look like.”
The findings are encouraging, Katz says, given the decline of Chinook salmon populations in recent years.“2006 through 2009 saw the smallest returns of fall run Chinook ever,” he says.
That’s fueled the state’s “fish vs. farms” political fight. Katz says the key is creating partnerships with farmers, and making sure the salmon don’t interfere with rice planting season. “We can create a system that really is win, win, win,” he says.
Brennan says other rice farmers are also interested in the project, where the fields are managed to attract migrating birds, provide habitat for salmon and produce a rice crop in the summer.
“Having all three of those uses on the landscape makes all of them more sustainable,” Brennan says. “Everybody always wants their one thing to be 100 percent. We can run all three at 90 percent and make all of them work.”
The results of the project could play a role as water battles heat up over Governor Jerry Brown’s proposal for the Sacramento-San Joaquin Delta. Getting the green light to build two 35-mile tunnels will largely depend on the long-term recovery of the Delta’s salmon.