By Gary Reedy, SYRCL River Science Director
Daguerre Point Dam is a known impact to salmon as they migrate both upstream and downstream in the lower Yuba River, but for the time being the antiquated ladders at the dam
house some highly sophisticated fish counting equipment. Those infrared-image capturing devices have just begun to detect the first spring-run Chinook salmon. May is the big month for spring-run Chinook salmon to arrive in the Yuba River, but big is not what it used to be. Less than 300 fish total for the season were counted in each of the last 3 years.
Chinook salmon returns throughout the Central Valley were very low again last year, prompting fishing closures and aggressive work by SYRCL and other organizations to remediate causes of the decline. Spring-run and winter-run Chinook salmon of the Central Valley have been officially “Threatened” with extinction since 1999, but the more abundant fall-run had been thought to be more secure owing to the fact that much spawning habitat still exists below dams and several large hatcheries maintain high levels of production.
Less than 38,000 fall-run salmon returned to the Central Valley in 2009, the lowest return on record. This is 10% of the best runs within recent decades, and a fraction of what is required to fully seed spawning habitat. The Yuba River fared a bit better than most rivers with 3600 fall-run salmon returning compared to a post-dam average of 15,000. The Yuba River is the only large river in the Central Valley without a salmon hatchery.
Recent research indicates that 90% of salmon returning to the Central Valley are from hatcheries. Despite being genetically and competitively less fit, hatchery fish are overwhelming wild fish due to the massive production of smolts using artificial rearing and transportation methods. Strays from the Feather River hatchery have already changed Yuba River by mixing and introgressing. Reformed hatchery management is one of many necessary actions to protect and restore wild Yuba River salmon.
The National Marine Fisheries Service (NMFS) recently released a draft of the Recovery Plan for Central Valley winter-run Chinook, spring-run Chinook and steelhead trout. This plan affirms the work that SYRCL is doing to rehabilitate rearing habitat in the lower Yuba River, remedy the problems of the Army Corps dams, and develop means to reintroduce salmon and steelhead to the upper watershed. In addition SYRCL is working cooperatively within the hydropower relicensing process, and with our partners in the Yuba Accord to gather valuable information and promote recovery scenarios.
While it may be impossible to ever restore the historic abundance of salmon in the Yuba watershed, it is possible to recover from the threats of extinction and ensure that our seventh generation will have wild salmon in their waters. That’s about 70 salmon generations, and nearly enough time to start recovering from the genetic damage done by isolating salmon below dams to interbreed with hatchery fish.
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