The winter-run Chinook salmon population continues to hover around historic lows in the Sacramento River, but Sacramento Valley farmers are working together with scientists to grow fish food on their rice fields in hopes of reversing this troubling trend.
Scientists involved in the project highlighted plans and recent achievements at Davis Ranches in Colusa on February 19th as part of the annual “Bird Day” event, which celebrates efforts to provide habitat for native wildlife in concert with active rice growing.
While farmers have been working for decades to aid bird populations, a new “Fins and Feathers” program is now working to create salmon habitat and fish food on these same farm fields.
The project – Fish Food on Floodplain Farm Fields – is a partnership between UC Davis Center for Watershed Sciences, Cal Trout, California rice farmers and water suppliers in both northern and southern California. The group is using existing fields to “grow” tons of bugs that fish like salmon love to devour.
“We like to think of these bugs in the water as floating fillet for the salmon,” said Cal Trout Senior Scientist Jacob Katz. “The fatter these little fish get from the bugs produced on rice fields, the better chance they have to survive the treacherous journey to the ocean and come back to the Sacramento Valley in three or four years as big adults.”
Just in its second year, the program is already yielding results that reveal great potential for increasing the amount of food available to fish populations, including endangered salmon and smelt.
“The amount of zooplankton and invertebrates (fish food) produced on the rice fields has far exceeded our expectations,” said Carson Jeffres, a researcher with the UC Davis Center for Watershed Sciences. “We have great hope that this project will serve as a model that can be implemented at a larger scale in the near future.”
This is the latest effort tied to the Sacramento Valley Salmon Recovery Program, a collaborative effort of farmers, fisherman, conservationists, government agencies and water suppliers which aims to reverse the population decline of the winter run Chinook salmon.
Recent surveys are startling, revealing that fewer than 2,000 fish are making the journey each winter from the San Francisco Bay to the upper channels of the Sacramento River. In the mid-1970s, those numbers totaled more than 25,000.
This isn’t the first time farmers in the Sacramento Valley have stepped up to implement large-scale conservation measures for wildlife. Starting the 1990’s, farms like Davis Ranches and River Garden Farms in Knights Landing began working with bird conservation groups and government agencies to make their fields friendlier to ducks and geese. That program, which saw farmers managing their lands to create winter wetland habitat by re-flooding their rice fields in fall and winter, helped fuel a recovery in native and migratory bird populations. Now, farmers are finding another use for their fields – feeding salmon.
“Fish food is made on the floodplain,” Katz said. “These farmers are essentially reconnecting this critical wetland energy source to the river channels where fish can make use of it.”
“By borrowing water from the river for a few weeks, and spreading it out over our fields, we are mimicking how water used to flow through the natural floodplain wetlands that once covered the valley floor,” said Roger Cornwell, manager of River Garden Farms. “When we return the water to the river, it’s supercharged full of fish food.”
As shallow water sits in agricultural fields, microbes start to breakdown the plants that grew during the previous summer. These broad, shallow puddles also allow algae to flourish. Both the algae and the decomposing plant matter feed the bugs that are a primary food source for fish.
This effort is crucial because modern development has turned rivers into food deserts for fish. Since European settlement more than 95% of the Central valley’s historic floodplains have been cut off from the river by levees. Today, Central Valley rivers are too swift and deep to create the natural flow patterns that are conducive to producing food for fish.
“We all agree that fish need water. This project acknowledges that they also have to eat,” says Katz.
“This is the natural progression for farmers in northern California,” said James. “Farmers see the many benefits biodiversity brings to an operation when the same acreage can produce food for people, birds, and fish. It is about changing the conversation to integration through collaboration. Here at Davis Ranches we are successfully installing native habitats, both seasonal and permanent, within our working farm lands.”