The northern end of California's Central Valley was once a miles-wide flood plain straddling the Sacramento River - a natural feeding ground for fish.

Today, California's wetlands have all but disappeared, turned into farms and cities ...

But now, California rice farmers and ecologists - often on opposing sides of California's contemporary water wars - are working together to reclaim the great flood plains... giving salmon a much-needed place to grow and feed.

Andrew Rypel is a professor of fish ecology at the University of California, Davis.

"So if you were to go back in time and just look at this landscape 300, 500 years ago, this would all be a giant floodplain. And this was habitat that chinook salmon, which are very important to California, use to rear on their way to the ocean. A lot of that habitat is gone now, but we have 500,000 acres of this stuff: California rice. Most of the sushi rice in the US comes from this area, and we think it can be useful for salmon conservation."

In an experiment a decade in the making, biologists are releasing hatchery salmon into flooded rice fields, seeking to reverse the trend of dwindling fish populations.

"It's important because we're losing species, so our current estimates are that about eighty three percent of the native California fishes are in severe decline. And salmon are no exception."

The university's researchers have joined the California Rice Commission and U.S. Department of Agriculture on the project in which the salmon are measured and tracked with microchips.

For graduate researcher Alexandra Wampler, every step of the project is exhilarating.

"Playing with fish. No, I'm sorry. My favorite part is definitely tracking the migration, seeing their data points show up on the receivers after we release them. It's very exciting to track where they went."

For the cost and inconvenience of flooding their fields, rice farmers are earning goodwill.

They're also betting that a healthy salmon population will avoid regulatory risk and ensure adequate water supplies in the future.

Steven Neader is one of the participating farmers.

"You know this month of the year, there's nothing going on here. We can't really work the ground and so it doesn't really help us, but it doesn't hurt us at all, either. And I think it helps the fish population. So, you know, we feel like if we can help with that, you know, we don't mind doing it."

Coincidentally, biologists discovered that decomposed rice straw brews a broth rich in fish food. They call it "zoop soup."

RYPEL: "So if you were to just scoop up the water, you'll see these little bugs swimming around in the water. Those are zooplankton, and they grow naturally off of the rice straw in these habitats. And those zooplankton are like the filet mignon of chinook salmon."

The hope is that the young salmon, after feasting on the rice field zooplankton, will make their way back to the river and out to sea.

So far the results show that juveniles feeding the rice fields grow two to five times faster than those in the river channel, that's according to Carson Jeffres, another UC Davis professor.

The salmon project uses 389 acres on a pair of rice farms about 30 miles northwest of Sacramento.

Though the experiment has been tried with small parcels, this is the first time salmon are being placed across a fully operating rice farm in a way that conservationists hope to replicate on a larger scale in years to come.

Paul Buttner is the manager of environmental affairs at the California Rice Commission.

"It's really important for us to try to do what we can do for salmon in the valley. They are struggling. They historically used this very bypass here that is now AG (agriculture) lands. We're lucky to be able to inundate it, be able to inundate it through management. And so, what we're trying to do is really to try to reactivate this floodplain and give the salmon a little bit of this floodplain back that they historically relied on."