Farmers Flood Their Rice Fields to Bring This Fish Back (and It Worked!)

A group of scientists, rice farmers, and conservationists joined forces to revive the Chinook salmon population in California, the United States, a marine species on the verge of extinction, and the decade-long project is delivering positive results.

They wanted to answer a simple question: if they were to flood rice fields with water from the Sacramento River — effectively mimicking the region’s original ecological rhythms — would juvenile salmon take to the fields and grow? “The answer was that they not only survive, but they also grow extremely well,” says Andrew L. Rypel, professor of fish ecology at UC Davis and co-director of the Center for Watershed Sciences. “The fish were feeding on lush zooplankton that develops off the decomposed rice straws.”

Through the “salmon-rice project”, the team discovered that rice straw is a rich source of carbon beneficial to the growth of zooplankton, the salmon’s main source of feeding, so much so that 50 to 80% of juvenile salmon survived in flooded rice and grew two to five times faster than in the Sacramento River. Last year, UC Davis scientists received $550,000 to expand their research – like trying on production-scale rice farms – and the data they gathered so far is encouraging: fish survive at a rate four to five times higher than when grown in labs.