January 27, 2026
Mokelumne River salmon returns highlight hatchery program success
River Management, Hatchery Operations Achieve 7.5 Million-Egg Target
OAKLAND – The East Bay Municipal Utility District (EBMUD) reports more than 10,500 Chinook salmon returned to the Mokelumne River from the Pacific Ocean to spawn during the 2025 fall run. These returns represent a healthy count for natural spawning in the river and allowed EBMUD’s fish hatchery to reach its goal of collecting and fertilizing 7.5 million salmon eggs in coordination with the California Department of Fish and Wildlife (CDFW).
Though the Mokelumne contributes only about 3 percent of the freshwater flow into the Sacramento-San Joaquin Delta, its salmon population has made up as much as 50 percent of the commercial catch off the California coast.
“These results reflect EBMUD’s dedication to the stewardship of the Mokelumne River, our commitment to habitat restoration, and our investments in science-driven fish hatchery operations and river management,” said EBMUD Board President Luz Gómez. “We are proud of our successful partnership with the California Department of Fish and Wildlife and thank our many local, state, and federal partners as we work together to strengthen California’s salmon populations and protect our vital natural resources.”
The Mokelumne River is the primary drinking water source for more than 1.4 million EBMUD customers in Alameda and Contra Costa counties. It also supports one of California’s most robust salmon populations. As part of EBMUD’s mission to balance customer water needs with natural resource protection, the not-for-profit public agency manages river flows, enhances habitat and funds the Mokelumne River Hatchery, which is operated below EBMUD’s Camanche Dam in partnership with CDFW.
Mokelumne Chinook salmon return to their home waters to reproduce and die after spending two to five years maturing in the Pacific. The journey marks a significant stage in the salmon life cycle and is a strong indicator of the habitat's ecological health and the population's survival rate. EBMUD counts these salmon returns every year during the spawning season, which typically runs from September to January. This year’s tally is roughly in line with the Mokelumne’s average of about 11,100 salmon annually since 1998.
EBMUD and CDFW’s science-driven hatchery operations and river management program support two overarching goals: continuing to enhance the natural, in-river production of Chinook salmon and steelhead while also advancing high survival rates to the ocean of our hatchery production. EBMUD works to provide spring inundation flows that support juvenile success and fall pulse flows that help attract fish home while maintaining sufficient cold water in Camanche Reservoir to provide good spawning conditions.
In 2023 and 2024, the Mokelumne River experienced record runs of salmon returning to spawn due in part to the closure of the ocean commercial and recreational fisheries. Long-term strategies and actions that support the fishery 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 CDFW, and with recent funding provided by the California Department of Water Resources under the Healthy Rivers and Landscapes Program Early Implementation actions.
- Flow management, including fall 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 to improve survival to the ocean; and management of the fish ladder leading into the hatchery to support both hatchery and natural spawners.
“We are pleased to again meet our in-river spawning targets and reach all our hatchery goals to support one of the West Coast’s most critical salmon populations,” said EBMUD Manager of Natural Resources Michelle Workman. “We had limited water available for pulse flows to attract migrating fish due to the drier year, but our management strategies and hatchery investments to support Chinook on the Mokelumne have proven to be resilient. In addition to a strong Chinook salmon run, this year supported a successful run of over 730 steelhead in the hatchery, a result of careful management and release strategies to support this federally threatened species.”
Available for interview:
EBMUD Manager of Natural Resources Michelle Workman (available virtually).
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The East Bay Municipal Utility District has a proud history of providing high-quality drinking water for 1.4 million customers in Alameda and Contra Costa counties. EBMUD’s wastewater system serves 740,000 customers and helps protect the ecosystem of San Francisco Bay. EBMUD is a not-for-profit public agency established in 1923.