Clements — A record number of over 20,000 fall-run Chinook salmon have returned to the Mokelumne River, a tributary of the San Joaquin River in the Central Valley, despite low returns on other Central Valley rivers.
The fish are now returning from the ocean in a year where all salmon fishing was closed in California’s rivers and ocean waters, due to the projected low abundance of Sacramento and Klamath River fall-run Chinook salmon. Fishery managers and salmon advocates are keeping a close eye on this fall’s spawning escapement.
The East Bay Municipal Utility District (EBMUD) today reported the 2023-24 fall run of Chinook salmon on the Mokelumne River is now “the most successful return in more than 80 years.” More than 20,000 fish – and counting – have returned from the Pacific Ocean to spawn in the river, the most since record keeping began in 1940.
“This year’s historic return highlights EBMUD’s longstanding collaboration in the region and our deep commitment to sustaining this vital fish hatchery and protecting the river’s habitat,” said EBMUD Board President Andy Katz. “We are proud to celebrate this achievement with our local, state and federal partners, as well as the broader community, which has entrusted us with safeguarding this precious natural resource.”
Amazingly, the Mokelumne River contributes only about 3 percent of the freshwater flow into the Sacramento-San Joaquin Delta, yet its salmon population makes up as much as 50 percent of the commercial catch off the coast of California in years when the season is open, according to data from the Pacific Fishery Management Council (PFMC).
On October 29 of this year, EBMUD biologists tallied the largest one-day salmon count in 30 years of 1,941 fish.
“The science-driven hatchery management program by EBMUD and CDFW includes operations that support ocean fisheries and natural spawning on the river,” according to EBMUD in a statement. “When the season is complete and full data is available, experts will determine which strategies contributed most to the success on the Mokelumne, given some rivers are experiencing low returns, as has the Mokelumne in previous years.”
Long-term strategies cited by the water agency include:
- “Habitat enhancement to improve natural river spawning and rearing, in partnership with both the U.S. Fish and Wildlife Service’s Anadromous Fish Restoration Program and the CDFW.
- Flow management, including pulse flows from EBMUD’s Camanche Reservoir into the river to attract returning fish; coordination with the U.S. Bureau of Reclamation to close the Delta Cross Channel to reduce straying; and management of the Camanche cold water pool to support spawning, incubation, and rearing.
- Hatchery management, including investments in chillers and ultraviolet filters to improve egg survival; collaboration on the release of juvenile fish; and management of the fish ladder leading into the hatchery.
- Statewide closure of California’s 2023 commercial and recreational salmon fishing season to protect the Central Valley fall-run Chinook population; the commercial and recreational salmon fishing fleet, which funds the production of ocean enhancement fish at the hatchery, forewent the season and contributed to this year’s success.”
“The Mokelumne faces many challenges,” said EBMUD Manager of Fisheries and Wildlife Michelle Workman. “It is a small river that can be overwhelmed by flows from larger Central Valley rivers when attracting salmon back from the ocean. But through collaborations with our agency partners, we have found winning strategies. This year’s large run allows us to meet our hatchery goals as well as improve natural production numbers in the river by maximizing the use of the available spawning habitat we worked so hard to build. Decades of work to improve the natural habitat are paying off.”
Workman said the hatchery is working towards its 10 million egg-take goal to produce approximately 9 million smolts, including the required 3.4 million mitigation fish, 3 million enhancement fish, and 2.5 million drought recovery fish. The mitigation fish are funded by EBMUD, the enhancement fish are funded through the ocean commercial and CPFV (Commercial Passenger Fishing Vessel) salmon stamp and the drought recovery fish are funded by the CDFW.
The majority of the enhancement fish will be trucked to release sites spanning Fort Baker, Richmond, Marin Rod & Gun Club, Tiburon, Half Moon Bay, Santa Cruz, and Monterey in 2024. The mitigation fish will be released at Sherman island.
Last year a total of 6.4 million salmon smolts were produced at the Mokelumne River Fish Hatchery.
“We are proud of the collaboration between EBMUD and CDFW and we attribute much of our success to our partnership,” concluded Workman. “This large run translates into meeting the hatchery goals and also being able to fill all of the restored habitat that we spent millions of dollars creating over the past 30 years.”
The Mokelumne River serves as the primary drinking water source for 1.4 million customers served by EBMUD in Alameda and Contra Costa counties. The not-for-profit public agency said it is “dedicated to balancing customers’ water needs with environmental protection and river stewardship.”
To mitigate for habitat losses that resulted from construction of Camanche Dan, EBMUD manages river flows, enhances habitat, and funds the Mokelumne River Fish Hatchery, operated in partnership with the California Department of Fish and Wildlife (CDFW).
The total numbers of hatchery and naturally spawned fish returning to the Mokelumne, American, Feather and Sacramento River and their tributaries won’’t be known until the numbers of fish returning to the hatcheries and carcass counts on the rivers are compiled by the CDFW and NOAA Fisheries in January 2024 in preparation for the Pacific Fishery Management Council meetings that craft the fishing seasons and restrictions.
Nimbus Fish Hatchery
Salmon are also returning now to the American River’s Nimbus Fish Hatchery. The fish ladder at the hatchery opened on Friday, November 3. Egg-taking began on Monday, November 6.
The hatchery will be taking eggs to reach a production goal of 4.5 million smolts and an additional 2 million fry, which will have parent-based tagging, according to Cat Kaiser, operations and events director for the Golden State Salmon Association.
Feather River Fish Hatchery
The Feather River Hatchery in Oroville is close to meeting its egg-take goal of 11 million with a 9.5 million smolt goal, Kaiser reported. Of those, 6 million are mitigation and 3.5 million are drought enhancement fish. Of that 3.5 million, 1.5 million fall run Chinook will be released as fingerlings.
“There are still a lot of fish in the Feather River (a little more than this time last year) and they will continue to spawn until the house is full and maximum capacity is reached. They have space for about 14-15 million eggs. One million of the fish will most likely be released into the river, depending on water conditions, with hopes of the rest being trucked,” Kaiser concluded.
Coleman National Fish Hatchery
The fish counts for the upper section of the Sacramento River are dismal. On Battle Creek, the Coleman National Fish Hatchery has only 5200 adult kings and 245 jacks. This is the second lowest total of all time, according to J.D. Richey in an action alert for the Nor-Cal Guides and Sportsmen’s Association (NCGASA).
In addition, biologists have found only 116 carcasses and 109 redds on the main stem of the Sacramento River this fall.
“They expect a little under 9 million eggs, translating into about 8 to 8.3 million smolts out of a goal of 12 million – falling well below targets,” reported Scott Artis, Executive Director of the Golden Gate Salmon Association (GSSA). “And to make things worse, 2024 will still represent returns from a drought year class. Thus, returns are expected to continue to be depressed until October 2025 when some better numbers are anticipated.”
Action Alert
The NorCal Guides and Sportsmen’s Association (NCGASA) is now urging people to participate in an action alert requesting 10-15 million salmon eggs to be be sent from other facilities so the Coleman National Fish Hatchery can come close to meeting their goals:
CALL TO ACTION: click the link below to send a prewritten petter to the Fishery Directors at CDFW and USFWS if you are concerned about the Sacramento fall salmon run and the future of the fishery. This letter is a request for the 10-15 million salmon eggs to be sent to Coleman National Fish Hatchery in order for them to come close to meeting their goals. They are hoping this can be done before Thanksgiving break. Find this letter on their website under NEWS: ncgasa.org/...