Flooded California rice fields provide critical habitat as scientist work to recover salmon populations
Building a bridge between farmers and wildlife conservation is the goal behind a new project designed to help salmon populations recover in California's Central Valley.
Researchers say winter flooded rice fields in the Central Valley can provide critical habitat for young salmon, giving them a stronger start on their journey to the ocean.
"Numbers have been pretty low the past few years," said Brett Galyean with the Coleman National Fish Hatchery. "Fishing hasn't been open. So we're partnering with folks to try different rearing techniques."
Researchers say the flooded rice fields can act like natural wetlands, similar to the floodplains that existed more than 100 years ago.
At Knaggs Ranch, located just outside of Woodland, a truck will release more than 300,000 baby salmon into this flooded rice field.
"The fish we put out here today are about the size of a paper clip, so they still need to grow," Galyean said. "By putting them on the rice field, they have the opportunity to put on that growth really quickly."
After more than a decade of research, scientists say salmon raised in flooded rice fields can grow two to five times bigger than those in rivers.
"When we see rice fields, we see them as surrogate wetlands for fish," said Carson Jeffres, a UC Davis researcher in the Department of Environmental Science and Policy. "When that water spreads out and interacts with the land, it creates zooplankton or fish food."
Jeffres, who has been studying the idea for years, says in some cases, fish can grow up to eight times faster.
"When fish are leaving freshwater, one of the most important things is how big they are when they enter the ocean," Jeffres said. "Being a small fish in a big ocean is a tough go."
The salmon will stay in the rice field for a few months before migrating through each of the fields, making their way to the Sacramento River and eventually the ocean, before returning in about three years to spawn the next generation.
The field making it possible belongs to longtime rice farmer John Brennan.
"We grow rice in the summertime," Brennan said. "In the wintertime, this land is historic wetlands."
For farmers like Brennan, this isn't about choosing between rice production and the environment. Instead of changing what farmers do, the idea is to build on what's happening already, using the off-season to benefit fish, farmers and the water system they all depend on.
"We're not going to have a strong rice industry unless we have a cohesive water industry and the water industry is completely dependent on the fish," Brennan said. "So let's go to where the problem is and solve it."