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Challenges of Spring-Run Chinook Salmon 

It's hard to believe based on the sizes of their populations today, but long ago spring-run Chinook salmon (spring-run) were the most abundant run of Chinook salmon in California's Central Valley. Historically, spring-run migrated upstream starting in late March, held out through the summer in the cold-water pools that once existed in the upper reaches of the basin, then spawned during late spring and early fall. During the last century, approximately 95% of this critical cold-water habitat has been lost due to mining, water diversions, and dam construction (Yoshiyama et al. 2001). As a result, the once abundant Chinook salmon population experienced a drastic decline in the Central Valley. The continuous degradation of spawning and rearing habitat, ongoing fishing pressure, and an increase in predator populations has lead to the near extirpation of spring-run in all rivers in the Central Valley. In 1999, spring-run were listed as threatened under the Endangered Species Act.


In 1967, the Feather River Hatchery commenced spawning Chinook salmon to mitigate the loss of habitat resulting from the completion of Oroville Dam -- only eight miles of usable spawning habitat remain on the river. Feather River is presently the only hatchery in the Central Valley with a spring-run program, and they currently spawn and tag more than 2 million of the fish annually (Buttars 2012). However, due to the overlap in spawn timing between spring-run and fall-run, the two runs have interbred and are now genetically indistinguishable (HGMP 2010). Genetic analysis indicates that "spring-run" Chinook on Feather River are in fact fall-run fish with "spring-running" behavioral traits.


The Butte Creek watershed, like most watersheds in the Central Valley, has been transformed through levees and water diversions since the mid-1960s. Prior to 1960, Butte Creek supported a run of more than 6,000 spring-run, but a reduction in flow and numerous fish barriers decreased the population to only a few hundred fish in most years. Between 1977 and 1979, the Butte Creek spring-run population declined to just 238 fish, and genetic analysis confirms that the diversity of the gene pool has diminished as a result (Grand Tab 2013). In the early 1990s, fish passage improvement projects and baseline flow increases lead to a significant increase in the number of fish returning to Butte Creek, which now supports the largest naturally spawning spring-run population in the Central Valley (see Spring into action!). However, the "bottlenecking" of the gene pool that occurred in the '70s has significantly jeopardized the genetic integrity of spring-run on Butte Creek -- they are currently the least diverse of the Central Valley's spring-run populations, and therefore have a limited ability to adapt to environmental change.


Managing the future of spring-run is a challenge. There are currently efforts to restore spring-run to the San Joaquin River, which has been dry in most years since the completion of Friant Dam in 1942. The goal of the project is to establish a self-sustaining population of spring-run by 2024 using hatchery fish as surrogates. Now that habitat for spring-run is limited to the reaches below Friant Dam and the genetics of the population have been compromised, reintroduction will be a difficult task -- nearly as difficult as restoring the entire river itself.


Figure 1. Spring-run Chinook salmon observations on Butte Creek (green) as well as the entire Central Valley (blue) (data from GrandTab report 2013).
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An early morning adventure 

It takes a real deep-seated desire for a fishing trip to awaken at 1 am after only a couple hours of sleep-and that's exactly what we have been doing over the past couple of weeks. For fishermen, traveling several hours before daybreak is a small price to pay for a chance to land the king of all salmon, the mighty Chinook. Most of us who choose fisheries management and research as a career do so because of a love of the sport, and have spent our youth honing our angling skills.


Recreational salmon fishermen are used to the ebb and flow of fishing opportunities-so when fishing is good, they come out in droves. Recently, one of the best places to catch salmon off the California coast has been out of Bodega Bay. On our first voyage out earlier this summer, we arrived to find a line of vessels near the boat launch reminiscent of L.A. gridlock. But as though choreographed, trailers quickly dipped into the salty water one after another, and boats were swiftly on their way.

Unlike fishing trips to seek solitude along an unspoiled section of river (see Gone fishin'), ocean salmon fishing can turn into a sort of combat fishing, requiring skilled navigation through a throng of vessels trolling in the surf. Recently, hundreds of boats have been taking to the water for anglers to catch their daily limit of 2 salmon, many over 30 lbs. According to the Pacific Fishery Management Council's Pre-season Report, recreational fishermen will catch 96,600 Central Valley Chinook in marine waters this summer-and we don't mind doing our share to reach that prediction. Read more>
IN THE NEWS: Recent stories you might have missed...
Butte Creek fish survival lauded as a victory this year
Oroville Mercury Register 

Fingers are crossed that the threatened spring-run chinook salmon in Butte Creek will continue to make it through this long, dry, hot summer.
Fish biologists and wildlife managers gathered near Centerville Powerhouse Thursday to recap the water management that saved thousands of fish.
A noteworthy number of fish migrated up Butte Creek this year - an estimated 10,000-16,000. In 2003, a similar amount made the journey... Read more > 

Fukushima leaks will keep fisheries closed   

New Scientist  

Over two years after the Fukushima Daiichi nuclear plant in Japan was devastated by a tsunami, radioactive water is still leaking into the ocean, spelling more trouble for the local fishing industry along the coast of Fukushima prefecture. Last month the plant's owner, Tepco, finally admitted what many had suspected - that the plant was leaking. Now Japan's Nuclear Regulatory Authority is calling the situation an emergency, and says Tepco's plans to stop the leak are unlikely to work... Read more > 

Extra water releases planned to protect Klamath River salmon
Sacramento Bee

The U.S. Bureau of Reclamation will release extra water from Lewiston Dam on the Trinity River next week in hopes of preventing a large fish kill downstream on the Klamath River. In a decision signed Wednesday, the releases will begin Aug. 13 from the dam, which impounds water in Trinity Reservoir upstream of the Klamath River. The extra flows will range between 1,000 and 1,200 cubic feet per second through September, with pulse flows as high as 2,700 cfs between Aug. 26 and 27. The move is intended to avoid a massive fish kill like one that killed tens of thousands of fall-run Chinook salmon in 2002... Read more >  

Pink salmon harvest exceeds 95 million fish
The Cordova Times

Wild Alaska salmon commercial harvests in Alaska surged to over 140 million fish through Aug. 6, with the catch of pink salmon alone climbing to 95,618,000 fish. In a strong run, with heavy fishing, it is going to be a good year for folks in most commercial fisheries, said Geron Bruce, assistant director of the Alaska Department of Fish and Game's Division of Commercial Fisheries. The harvest through Aug. 6 exceeded 140 million fish, including the more than 95 million...  Read more > 

Old Hawaiian menus tell story of local fish and their demise

In the early to mid-1900s, the islands of Hawaii were a far-away, exotic destination. People who managed to get there often kept mementos of that journey including kitschy menus from Hawaiian fine dining restaurants and hotels like like Trader Vic's and Prince Kuhio's. Now these old menus are serving a purpose beyond colorful relics from the past. Kyle Van Houtan, an ecologist with the National Oceanic and Atmospheric Administration, says he's found a scientific purpose for the menus... Read more >