Wednesday, July 23, 2014
YOLO COUNTY NEWS
99 CENTS

For fish and rice to thrive in Yolo Bypass, ‘just add water’

rice fish3W

Nick Corline, a junior specialist at the UC Davis Center for Watershed Sciences, gently tips a bucket of baby salmon into a mesh enclosure. Researchers tagged 800 baby salmon to identify them as wild or hatchery fish, and released them into pens on 20 acres of inundated Knaggs Ranch rice-farm fields in the Yolo Bypass floodplain, on Wednesday, February 20, 2013. Scientists with the UC Davis Center for Watershed Sciences, the state Department of Water Resources and California Trout are investigating whether the Central Valley's river floodplains could be managed to help recover California's populations of Chinook salmon.

By
From page A1 | October 25, 2013 |

From a fish-eye view, rice fields in California’s Yolo Bypass provide an all-you-can-eat bug buffet for juvenile salmon seeking nourishment on their journey to the sea.

That’s according to a new report detailing the scientific findings of an experiment that planted fish in harvested rice fields earlier this year, resulting in the fattest, fastest-growing salmon on record in the state’s rivers.

The report, provided to the U.S. Bureau of Reclamation, describes three concurrent studies from researchers at UC Davis, nonprofit California Trout and the California Department of Water Resources. The scientists investigated whether rice fields on the floodplain of Yolo Bypass could be managed to help recover California’s populations of Chinook salmon, and if so, the ideal habitats and management approaches that could allow both fish and farms to thrive.

“We’re finding that land managers and regulatory agencies can use these agricultural fields to mimic natural processes,” said co-author Carson Jeffres, field and laboratory director of the Center for Watershed Sciences at UCD. “We still have some things to learn, but this report is a big step in understanding that.”

Researchers found that the fish did not have a preference among the three rice field types tested: stubble, plowed and fallow. The food supply was so plentiful that salmon had high growth rates across habitats and management methods.

“It’s like a dehydrated food web,” said Jeffres of the harvested rice fields. “Just add water. All of those habitats are very productive for fish.”

The salmon did demonstrate a preference for habitats with better water flow. Jeffres compared it to choosing among three good restaurants: Each offers good food with hearty portions, but one has better ambience and so is chosen above the others. In this case, the better water flow was the ambience the fish preferred.

Among the key findings:

* Experimental flooding of Yolo Bypass rice fields during the winter can create productive aquatic food webs for salmon.

* Average growth rates during the study’s 41 days were the highest recorded in fresh water in California. Growth of juvenile Chinook averaged 0.93 mm per day, with growth of 1.5 mm per day observed during specific two-week intervals.

* Mortality was greater than in the team’s previous 2012 study at Knaggs Ranch. In the 2013 study, between 0 and 29 percent of free-swimming fish survived, while 35 to 98 percent of fish in enclosures survived.

* Lower survival rates were attributed to bird predation. The winter of 2013, when the study was conducted, was one of the driest on record in the Sacramento Valley, which may have drawn more birds to the inundated rice fields, and to the fish. The study plots also were relatively shallow, providing little escape for fish. A follow-up study planned for 2014 will explore the role of depth as a refuge for fish against avian predators.

* Fish reared in plowed rice fields grew faster than those reared over stubble or weedy vegetation. However, all habitat types were beneficial to the fish, suggesting farm managers may have more flexibility in land treatment after harvest.

“These results are good news for the effort to rebuild salmon populations in California,” said lead author Jacob Katz, a biologist with California Trout. “We’ve always suspected that when we mimic natural flood processes in agricultural fields, we give these fish a food-rich habitat they recognize and thrive in.

“These findings support that theory and provide a strong path forward for California land-use planners, conservationists and farmers alike. This is a win-win model that can be replicated around the state.”

The Yolo Bypass is the Central Valley’s largest contiguous floodplain and provides critical fish and wildlife habitat, the report said. It is covered by floodway easement held by the state of California, making other land uses subservient to flood control. Agriculture is a major land use in the bypass, with rice the primary crop.

More than 95 percent of Central Valley floodplain habitat that was historically used to rear juvenile Chinook salmon has been altered, primarily diked, and drained for agriculture conversion. Most former floodplain wetlands are now only inundated during major floods. The report said access to floodplain habitats and the high growth rates associated with them during even a limited time may be critical in improving return rates for Central Valley salmon populations.

The project was completed in collaboration with landowner partners Cal Marsh and Farm Ventures, and Knaggs Ranch, with funding from California Trout, Knaggs Ranch LLC, Metropolitan Water District of Southern California, Resources Legacy Fund, State and Federal Contractors Water Agency, and the U.S. Bureau of Reclamation.

— UC Davis News

LEAVE A COMMENT

Discussion | No comments

The Davis Enterprise does not necessarily condone the comments here, nor does it review every post. Read our full policy

  • Recent Posts

  • Enter your email address to subscribe to this newspaper and receive notifications of new articles by email.

  • .

    News

     
    Second Mellon grant supports Mondavi events

    By Jeff Hudson | From Page: A1 | Gallery

    Are arachnids awesome or awful? Visit Bohart Museum to find out

    By Kathy Keatley Garvey | From Page: A1 | Gallery

     
     
    Police arrest suspect in robbery spree

    By Lauren Keene | From Page: A2

    Madhavi Sunder joins Davis school board race

    By Jeff Hudson | From Page: A2

     
    Crews make gains on massive Washington wildfire

    By The Associated Press | From Page: A2

     
    New safety rules proposed to curb oil train fires

    By The Associated Press | From Page: A2

    Grandparents support group meets weekly

    By Enterprise staff | From Page: A3

     
    Kaiser awards grants to Yolo nonprofits

    By Special to The Enterprise | From Page: A3

    NAMI program offers mental illness information, support

    By Enterprise staff | From Page: A3

     
    Backpacks for Kids launches annual donation drive

    By Enterprise staff | From Page: A3

     
    Architecture in Davis, on ‘Davisville’

    By Enterprise staff | From Page: A3

    Speaker will spin some fishing tales at Davis meeting

    By Special to The Enterprise | From Page: A3 | Gallery

     
    Kids can paint their own Breyer horses at Davis store

    By Enterprise staff | From Page: A3

    Car lovers will speak Sunday at gallery

    By Enterprise staff | From Page: A4

     
    Racial diversity crucial to drug trials, treatments

    By San Francisco Chronicle | From Page: A4

    Exchange program seeks host families

    By Special to The Enterprise | From Page: A4

     
    Wine-tastings will benefit YCCC

    By Enterprise staff | From Page: A4

    Pedro party will benefit Yolo Hospice

    By Enterprise staff | From Page: A4

     
    Quaff a beer and watch the bats

    By Enterprise staff | From Page: A5 | Gallery

    Enterprise is focus of Davis Roots talk

    By Enterprise staff | From Page: A5

     
    .

    Forum

    They’re pickier than she is

    By Creators Syndicate | From Page: B5

     
    U.S. is complicit in attack

    By Letters to the Editor | From Page: A6, 3 Comments

    Extinguish extremism for peace

    By Letters to the Editor | From Page: A6, 3 Comments

     
    With profound gratitude

    By Letters to the Editor | From Page: A6

     
    Someday, there will be peace

    By Rich Rifkin | From Page: A6

    Tom Meyer cartoon

    By Debbie Davis | From Page: A6

     
    .

    Sports

    Former Davis man at crossroads: biking or artwork?

    By Bruce Gallaudet | From Page: B1 | Gallery

     
    Aggie golfer headed to men’s U.S. Amateur Championship

    By Special to The Enterprise | From Page: B1 | Gallery

    Giants outlast Phillies

    By The Associated Press | From Page: B1 | Gallery

     
    River Cats nip dogs

    By Enterprise staff | From Page: B1

    A’s fall in extra innings

    By The Associated Press | From Page: B1 | Gallery

     
    Blue Jays hitting upends Red Sox

    By The Associated Press | From Page: B2

    Pyrenees please Nibali, Rogers in Tour Stage 16

    By The Associated Press | From Page: B3

     
    Albergotti to discuss Armstrong’s doping scandal

    By Bruce Gallaudet | From Page: B8

    .

    Features

    Field to Fork: Skyelark Ranch, not a lark at all

    By Dan Kennedy | From Page: A8 | Gallery

     
    Name droppers: ASUCD hands out awards

    By Enterprise staff | From Page: A8 | Gallery

    .

    Arts

    Village Homes to host Rita Hosking Trio

    By Enterprise staff | From Page: A7 | Gallery

     
    Tomato Festival makes call for young artists

    By Enterprise staff | From Page: A7

    Additional casting notice for ‘Hello Dolly’

    By Enterprise staff | From Page: A7

     
    Hear Los Tres de Winters on Thursday

    By Enterprise staff | From Page: A7

    Picott to play at The Palms Playhouse

    By Kate Laddish | From Page: A7

     
    Fairy-tale romance in Barnyard Theatre’s ‘Pinky’

    By Enterprise staff | From Page: A7

    Soar to Neverland with DMTC’s ‘Peter Pan’

    By Enterprise staff | From Page: A7 | Gallery

     
    .

    Business

    .

    Obituaries

    .

    Comics

    Comics: Wednesday, July 23, 2014

    By Creator | From Page: B6