Biologists are releasing hatchery salmon onto flooded Northern California ricefields in an experiment that has been a decade in the making. The goal is to replenish endangered fish species and benefit farmers’ business models.
At a time when environmentalists https://www.reuters.com/business/environment/california-hoopa-valley-tribe-try-save-salmon-way-life-2021-10-21 are often pitted against agribusiness in California’s water wars, conservation scientists and rice farmers are working together, trying to reclaim the great flood plains of the Sacramento River for salmon habitat https://www.reuters.com/world/us/after-rain-burst-california-salmon-reclaim-old-spawning-grounds-2022-01-19. Their task is difficult. California’s wetlands are almost gone. They have been converted into cities and farms in one of the greatest engineering feats or environmental crimes of the 20th century.
Rice farmers are now making goodwill out of the inconvenience and cost of flooding their fields. They hope that healthy salmon populations will be able to avoid new regulations that would protect wildlife and keep water flowing. Recent research has shown that rice straw in floodplains creates a rich fish-food broth. It is called “zoop soup”.
Andrew Rypel is a professor of fish ecology at University of California Davis and the lead investigator of this project. After consuming zooplankton, salmon return to the river to swim downstream and under the Golden Gate Bridge to their destination at sea. They will return years later to spawn their next generation.
The university’s researchers have joined the California Rice Commission, the conservation group California Trout and the U.S. Department of Agriculture on the project, seeking to reverse the trend toward dwindling fish populations as a result of human re-engineering of the state’s waterways and, in recent years, extreme drought exacerbated by climate change https://www.reuters.com/news/picture/severe-drought-marks-california-landscap-idUSRTXEEWPI. Rypel stated that they don’t want “to just sit silently as extinctions happen.”
Before industrialization, the northern part of California’s Central Valley was a flood plain measuring miles across that straddled the Sacramento River. This flood plain was a natural habitat for fish and provided a natural food source for them. California built two bypasses on the Sacramento River to control floods and irrigation after one too many floods in Sacramento.
This land is ideal for rice farming. Approximately 500,000 acres (200,000 ha) are currently under cultivation. The flood plain can be connected to the river, even though it will never return to its natural state. The flood plains can be used to improve the salmon habitat and increase the chances of survival.
Carson Jeffres, another researcher at the UC Davis Center for Watershed Sciences, stated that juveniles who eat in rice fields grow up to five times faster than those who eat in the river channel. Although the experiment has been done before on small areas of salmon, this winter it is being tested on large-scale rice farms. The model will be replicated on other farms over the next few years, conservation scientists hope.
The salmon project uses 389 acres (157 Hectares) on a pair if rice farms located at the Sutter Bypass, near Robbins, approximately 30 miles (50km) northwest of Sacramento. One farm is deliberately flooded with water and planted in hatchery fish. The biologists can track their movements and monitor their progress with microchips. A second farm is being prepared in case the Sacramento overflows. It will produce naturally spawned Salmon.
Engineering of the 20th Century rerouted California’s natural migration from north to south, speeding it. That turned the state into an economic powerhouse at the cost of decimating its fish https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=104268&inline. According to UC Davis researchers, 83% of California’s freshwater fishes are either in decline or extinct. This includes the endangered Chinook salmon and winter-run Chinook salmon. Salmon that mature early in life have the greatest chance of flourishing, but California’s flood plain lacks the nutrients necessary to support their growth.
Paul Buttner, of the California Rice Commission, stated that “We’re trying… to reactivate the floodplain and give salmon a little bit back of this floodplain that they historically relied upon.” The Pacific Flyway, which is a north-south corridor connecting North and South America, inspired the idea for the project.
California rice farmers had traditionally burned rice straw left over from their autumn harvests until 1991, when a state law outlawed the practice. This was largely due to concerns about smoke and health. The smoke cleared up and birds returned to the fields after farmers began using water to reduce rice straw. Although the rice fields are no longer pristine wetlands and California has lost 90% of them, enough migratory birds were attracted to the rice fields to make the sky darken again, their quacks and honks booming across the valley.
Rypel, a researcher from UC Davis, called it “one the great conservation stories of the U.S. history.”
(This story was not edited by Devdiscourse staff. It is generated automatically from a syndicated feed.