Chinook salmon captured underwater. Image credits: Wikimedia Commons
In 2022, California launched a trial floating system in Shasta Reservoir to help restore endangered winter-run Chinook salmon to their habitat in the McCloud River. In an update in January 2026, DWR reported that redesigning and relocating the collection system lessened predator presence around it and increased the number of fish collected. Climate change and drought place additional pressure on the species because warmer water can threaten the survival of eggs and young fish, according to DWR. Therefore, restoring access to colder historical habitat is a part of a broader effort to improve the population’s resilience to changing environmental conditions.
The California Department of Water Resources led the four-year pilot project. It tested whether young salmon migrating downstream could be collected before dispersing into the reservoir and transported around Shasta Dam. The construction of Shasta and Keswick dams in the 1940s blocked access to high-elevation, cold-water rivers where Chinook salmon spawned. These improvements represent progress in testing a fish-passage strategy, though they do not yet demonstrate that the fish population has recovered. Why California developed a floating salmon-collection system Winter-run Chinook salmon reportedly used the upper Sacramento River watershed, which included the McCloud River for spawning and early development. The fish population was left dependent on areas downstream of the dams after the construction of Shasta and Keswick dams, as they blocked their access to these upstream habitats. These lower-elevation waters can be challenging to manage during droughts and periods of high temperatures.
From initial testing to redesigning The project received $1.5 million in funding in February 2022. In 2022, no salmon were collected, as the priority was to test how the structure operated and determine how its position and layout could be improved. Image credits: Wikimedia Commons In 2023, the project expanded to include juvenile salmon collection. Information gathered during the pilot project informed an improved second version of the system in late 2025, according to the state agency’s January 2026 data. At least two pairs of adult winter-run Chinook salmon have migrated from the lake back into the McCloud River to breed, according to the 2026 report.
To evaluate the performance of the physical structure, the engineering team conducted efficiency releases by tracking hatchery-raised juvenile salmon introduced upstream of the JSCS and measuring the exact number successfully gathered in the trap.
DWR also conducted “efficiency releases,” in which hatchery-raised, tagged juvenile salmon were released upstream of the system so researchers could measure how many were captured later on. The central challenge faced by the project is getting juvenile salmon out of the McCloud River before they enter the much larger Shasta Reservoir. The Juvenile Salmonid Collection System (JSCS) uses a floating structure, guidance nets, a temperature curtain, a debris boom and a fish trap to direct migrating fish towards a collection point. Once captured, the young fish can be placed in transport containers and moved downstream around the dams, thus allowing them to continue their journey towards the Pacific Ocean. Following this, DWR began testing the first version of the collection system in September. During the initial phase, engineers and biologists evaluated the system’s hydraulic performance and temperature conditions. The McCloud river just below the Middle Falls. The changes reportedly reduced predator presence near the system and increased collection numbers. What the results mean for salmon recovery The larger reintroduction program seeks to repopulate winter-run Chinook salmon in their native range above Shasta Dam, while enabling their offspring to migrate downstream to the ocean. it does not provide evidence that the collection system alone led to their migration While the migration of these adult fish is promising for the reintroduction project. The project has involved DWR, the California Department of Fish and Wildlife, NOAA Fisheries, the Winnemem Wintu Tribe, the US Fish and Wildlife Service and other partners. This partnership brings together engineering, fisheries science, and Indigenous knowledge to tackle the problems created by the dams. You use AI every day. Now get your AI Quotient. Take the AIQ test.
Additionally, the department moved the collector from its earlier position where the McCloud River meets the reservoir into the river environment itself.
