Posts Tagged: salmon
California once teemed with millions of native salmon, trout and steelhead. The state has 31 distinct types of these iconic, majestic fish. But decades of degradation to aquatic habitat has depleted their numbers in many areas of the state. According to a report by UC Davis fisheries professor Peter Moyle and colleagues, 20 of these fish species are in danger of extinction within the next century. They are important species not just for the recreational or commercial benefits they afford, but also because they are a direct reflection of the health of the environment.
“Large self-sustaining populations of native salmon and trout are found where streams are in reasonably good condition,” Moyle wrote in his 2008 report, “SOS: California's Native Fish Crisis.” This report was commissioned by the conservation organization California Trout (CalTrout), which exists to support conservation science, education, and advocacy efforts to protect California's water resources and fisheries.
Moyle, whose academic home is the Department of Wildlife, Fish and Conservation Biology at UC Davis, is no stranger to CalTrout. He is the foremost authority on California's native freshwater and anadromous (sea-run) fishes and has been a leader in research and conservation efforts. His research has provided the core science essential to statewide conservation planning for freshwater and estuarine native fishes, especially salmon and trout. Graduate students who studied with Moyle now occupy many top-level fish ecologist and management positions in state and federal agencies, as well as key nonprofits like CalTrout.
In May of this year CalTrout and UC Davis announced the formal creation of the Peter B. Moyle and California Trout Endowed Chair in Cold Water Fishes. The endowment will provide crucial support for the chair holder's scholarly activities, teaching, and public service involving cold water fish and aquatic ecosystems. He or she will teach department courses, mentor graduate students, conduct research and outreach, and provide leadership in the conservation of cold water fishes and their ecosystems. The university recognizes that salmon, trout, and steelhead are the major drivers of many conservation efforts and will have the highest priority in the chair's program.
Most of the contributors to the endowment are CalTrout board members such as Nick Graves. He and his wife, Mary, explored many trails and trout waters in the Sierra Nevada over the years and have enjoyed larger rivers flowing from the Trinity Alps, Mt. Shasta, and the Siskiyou Mountains. “The opportunity to create a scientific chair whose research targets California waters, in perpetuity, is a comforting thought,” Graves said.
“I have worked with the organization since its earliest days and have always admired the dedication of its members to aquatic conservation,” Moyle said. “I am biased, of course, but I think CalTrout has made a very smart investment in the future by creating an endowed chair.”
From late fall through winter you can see thousands of ducks, geese and other waterfowl winging over the bypass’s flooded rice fields and the restored wetlands in the Vic Fazio Yolo Basin Wildlife Area.Learn more.
A recent article in The Sacramento Bee featured a research project at a rice farming area in the upper reaches of the bypass that is examining how flooded fields could be used to fatten up young salmon during a crucial time in their life cycle. One part of the study is examining how soil type influences the production of insects — an important source of food for growing salmon. Carson Jeffres, a fish ecologist with the UC Davis Center for Watershed Sciences, is quoted in the story: "There are hundreds, if not thousands, of insects that are coming out of each 9-by-6-inch block of earth." You can also watch a YouTube video to hear UC Davis doctoral student Jacob Katz describe the project and read more about why fish find this floodplain so attractive in a previous Green Blog post by writer and photographer Trina Wood.
Part of the wildlife area is accessible by automobile — when it’s not flooded! Consider taking a tour of this remarkable and easily accessible area, or take binoculars to view the many birds. UC Davis fisheries professor Peter Moyle prepared a guide that will help you make the most of your visit.
The competition between farmers and fish for precious water in California is intensifying in wine country, say biologists at the University of California, Berkeley.
The researchers found that juvenile steelhead trout are particularly at risk during the dry summer season typical of California’s Mediterranean climate. Of the juvenile steelhead trout present in June, on average only 30 percent survived to the late summer. In years with higher rainfall and in watersheds with less vineyard land use, the survival of juvenile trout over the summer was significantly higher.
The researchers pointed out that salmon and trout conservation efforts have not adequately addressed summer stream flow. Previous studies have highlighted other limiting factors such as habitat degradation and water quality, while this study documented the importance of water quantity for restoring threatened populations.
Grantham says he is not suggesting we get rid of vineyards. “But we do need to focus our attention on water management strategies that reduce summer water use. I believe we can protect flows for fish and still have our glass of wine.”
There are options for managing water resources to protect the salmon runs, although they would impact hydroelectric power generation, said UC Cooperative Extension associate specialist Lisa Thompson, director of the Center for Aquatic Biology and Aquaculture at UC Davis. A paper describing the study was published online recently in the Journal of Water Resources Planning and Management.
“There are things that we can do so that we have the water we need and also have something left for the fish,” Thompson said.
Working with Marisa Escobar and David Purkey at SEI’s Davis office, Thompson and colleagues at UC Davis used a model of the Butte Creek watershed, taking into account the dams and hydropower installations along the river, combined with a model of the salmon population, to test the effect of different water management strategies on the fish. They fed in scenarios for climate change out to 2099 from models developed by David Yates at NCAR in Boulder, Colo.
In almost all scenarios, the fish died out because streams became too warm for adults to survive the summer to spawn in the fall.
The only option that preserved salmon populations, at least for a few decades, was to reduce diversions for hydropower generation at the warmest time of the year.
“If we leave the water in the stream at key times of the year, the stream stays cooler and fish can make it through to the fall,” Thompson said.
Summer, of course, is also peak season for energy demand in California. But Thompson noted that it might be possible to generate more power upstream while holding water for salmon at other locations.
Hydropower is often part of renewable energy portfolios designed to reduce greenhouse gas emissions, Purkey said, but it can complicate efforts to adapt water management regimes to a warming world. Yet it need not be all-or-nothing, he said.
“The goal should be to identify regulatory regimes which meet ecosystem objectives with minimal impact on hydropower production,” he said. “The kind of work we did in Butte Creek is essential to seeking these outcomes.”
There are also other options that are yet to be fully tested, Thompson said, such as storing cold water upstream and dumping it into the river during a heat wave. That would both help fish and create a surge of hydropower.
Salmon are already under stress from multiple causes, including pollution, and introduced predators and competitors, Thompson said. Even if those problems were solved, temperature alone would finish off the salmon — but that problem can be fixed, she said.
“I swim with these fish, they’re magnificent,” Thompson said. “We don’t want to give up on them.”
Other co-authors of the paper are graduate student Christopher Mosser and Professor Peter Moyle, both in the Department of Wildlife, Fish and Conservation Biology at UC Davis. The study was funded by the U.S. Environmental Protection Agency.