Alameda Creek Alliance volunteers helped fish biologists last week from the East Bay Regional Park District capture and radio tag a single adult steelhead trout in lower Alameda Creek below the BART weir, an impassable concrete barrier that blocks fish spawning migration. On February 5, Park District biologists attached a radio transmitter to a 25” female steelhead and moved her upstream into lower Niles Canyon. This steelhead migrated into the Stonybrook Creek tributary, where she was observed last week spawning with native rainbow trout.

“Anna, our anadromous trout, was in a hurry to spawn and she quickly found good habitat in a Niles Canyon tributary and a willing mate among the native rainbow trout population there,” said Jeff Miller, director of the Alameda Creek Alliance. “We’ve had a handful of adult steelhead attempt to migrate up lower Alameda Creek each of the last four winters, but only a few have gotten a helping hand to suitable spawning grounds.”

The female steelhead has been nicknamed “Anna,” a reference to the anadromous, or migratory, life cycle of steelhead. “Anadromous” derives from Greek words meaning “up running.” Steelhead trout and rainbow trout are different forms of the same species. Steelhead have migrated from the fresh water streams of their birth to the ocean, whereas the smaller rainbow trout spend their entire life cycle in fresh water.

“Construction begins this summer on a fish ladder at the BART weir, which within three years will allow salmon and steelhead to migrate upstream on their own to reach suitable spawning areas in the Alameda Creek watershed,” said Miller. “Half a century after they were eliminated, we’re on the brink of restoring a wild steelhead spawning population in the largest local tributary to San Francisco Bay.”

Four adult steelhead were seen at the BART weir barrier on February 3 but only one steelhead was captured on February 5. A 29” chinook salmon was also captured, likely of hatchery origin. The Park District captures and radio tags steelhead to track their upstream migration. The Alameda County Water District and California Department of Fish and Wildlife helped coordinate the fish capture and tagging. Trout Unlimited, South Bay Clean Creeks Coalition and Diablo Valley Fly Fishers also provided volunteers.

Local, state and federal agencies have been working on multiple projects to restore steelhead trout to Alameda Creek. The Alameda County Water District and Alameda County Flood Control District will begin construction this summer on a critical fish ladder that will allow steelhead to migrate past the BART weir barrier and an adjacent inflatable rubber dam used for water supply operations. It will take three years to complete construction for this complex fish passage facility. The ACWD recently completed construction of another fish ladder at a second inflatable rubber dam one mile upstream in the flood control channel.

In 2018 the San Francisco Public Utilities Commission finished rebuilding the seismically-challenged Calaveras Dam in the upper Alameda Creek watershed. The new reservoir will be operated with cold water releases in the summer to help steelhead and trout rear downstream of the dam. The SFPUC also recently finished construction of a new fish ladder and fish screens at the associated Alameda Diversion Dam in upper Alameda Creek. This diversion dam will be operated to bypass much more of the winter and spring high flows in upper Alameda Creek. The enhanced stream flows will help migratory fish get further upstream to better habitat.

Alameda Creek is becoming an urban stream success story after decades of restoration efforts. Since steelhead trout in the Bay Area were listed as a threatened species under the Endangered Species Act in 1997, a consortium of organizations and agencies has cooperated on restoration projects to allow migratory fish to reach spawning habitat in upper Alameda Creek, including dam removals and construction of fish ladders and fish screens. Seventeen fish passage projects have been completed in the watershed since 2001. Water agencies are also working on projects to improve stream flows and restore stream and riparian habitat along Alameda Creek and its tributaries. These restoration projects will make up to 20 miles of Alameda Creek and its tributaries accessible to ocean-run fish for the first time in over half a century.

Alameda Creek is considered an ‘anchor watershed’ for steelhead, since it has regional significance for restoration of the threatened trout to the entire Bay Area. The watershed drains an area of about 680 square miles and once supported populations of native steelhead trout and salmon. Steelhead, salmon and lamprey are anadromous fish, living out their adult lives in the ocean and migrating up fresh water streams and rivers to spawn and rear their young. Construction of dams, water diversions, modifications to the Alameda Creek streambed, and urbanization made it impossible for steelhead to migrate upstream, eliminated access to suitable spawning areas, and reduced suitable habitat for cold-water fish.