Feather River Fish Monitoring Station Provides Improved Population Data on Fish Species

Since abundant running water first began flowing through the Sierra Nevada foothills to form the Feather River, fish species like Chinook salmon and steelhead have been migrating up from the Pacific Ocean to spawn. Listed as threatened under the Endangered Species Act due to population declines stemming from recent drought and reduced ocean food supplies, monitoring efforts are essential to track population trends and guide management and recovery efforts. With the installation of a fish monitoring station in the Feather River near Oroville, DWR can more accurately track the arrival timing, number, species, and origin (natural or hatchery raised) of returning fish.

 

“The fish monitoring station is a valuable reporting tool for counting Chinook salmon and steelhead populations in the Feather River,” said Byron Mache, Environmental Scientist with DWR’s Division of Integrated Science and Engineering. “Accurate estimates allow DWR and its partners, like the California Department of Fish and Wildlife and National Marine Fisheries Service, to track the success of hatchery activities along with environmental and fishing impacts.”

 

Located approximately 6.5 miles downstream of the Feather River Fish Hatchery, DWR’s fish monitoring station is located near the bottom of the low flow channel, a section of the river that offers lower river temperatures and improved gravel habitat, making it a prime holding and spawning environment. As fish migrate up the river, they are forced to pass through a chute in the monitoring station that spans the river channel. The chute contains an underwater camera that captures video of fish using motion detection software.

 

DWR scientists review the video footage to determine the exact species of fish and can check to see whether the adipose fin has been clipped. A clipped adipose fin indicates that fish are of hatchery origin. Since the monitoring station was installed, DWR scientists have recorded more than 10 different fish species in the Feather River, including Chinook salmon, steelhead, Sacramento pikeminnow, hardhead, pink salmon, chum salmon, American shad, and striped bass.

 

Prior to the construction of Oroville Dam in the 1960s, fish migrating from the Delta and Sacramento River could travel 170 miles or more to the upper reaches of the Feather River. Historically, spring-run Chinook salmon returning in April, May, or June would access the upper Feather River to hold and spawn thanks to higher river flows from winter rains and snowmelt. In contrast, fall-run Chinook salmon traditionally return in the fall, making the valley floor their natural spawning habitat.

 

With Oroville Dam preventing spring-run Chinook salmon from migrating further up the Feather River, they now spawn in the valley at a similar time as fall-run Chinook salmon, making it difficult to differentiate between the two using traditional survey methods.

 

“For years DWR and its partners have estimated fish populations by tracking how many fish entered the Feather River Fish Hatchery and through carcass surveys in the river,” says Mache. “This monitoring tool provides key data to California fisheries and water managers and significantly reduces staff time counting fish on the river.”

 

In previous years, DWR would have at least four boats a day on the Feather River with staff spending weeks at a time in the fall estimating the Chinook salmon population.  Carcass survey efforts have now been reduced by around 75 percent thanks to the installation of the monitoring station.

 

In 2024, DWR was able to track spring-run Chinook salmon returning to the Feather River as early as mid-March with more than 7,000 returning between March and the end of June. Approximately 17,700 spring-run were estimated in the Feather River in 2025, the best return since 2013. Chinook salmon that migrate up the river starting in July are considered fall-run, with the monitoring station tracking more than 40,000 fall-run between July 1 and Dec. 31, 2024.  

 

Population data from DWR’s Feather River Fish Monitoring Station is updated regularly on CalFish.org with overall Central Valley Chinook salmon population data reported in the California Department of Fish and Wildlife’s GrandTab report.

 

“With the improved data that the fish monitoring station provides, water managers will be able to ensure that these important fish populations are around for future generations,” Mache says.