Nandita Kohli (Former Employee)

This is a diagram of a cross section of a dam. This diagram is to show where gas bubble trauma could occur.

This is a photo of a fish with gas bubble trauma. For decades, scientists at the USGS Western Fisheries Research Center (WFRC) have worked alongside dam operators to monitor a lesser-known threat to fish in the Columbia and Snake rivers: gas bubble trauma.

To understand gas bubble trauma, imagine scuba divers surfacing too quickly. As pressure decreases, dissolved gases in their blood can form bubbles, causing joint pain, paralysis, and even death—a condition commonly known as “the bends.” Fish can experience something similar. 

Since the early 1990s, WFRC has supported state and federal agencies by providing regular assessments of gas bubble trauma in salmon. But salmon aren’t the only fish affected. In 2020, scientists at the Cook lab began monitoring GBT in resident species like sculpin, northern pikeminnow, and three-spined stickleback.

Invasive species present a growing threat to ecosystems worldwide, and the African clawed frog (Xenopus laevis) is no exception. First detected in the U.S. in 1964, African clawed frogs have now made their way to Washington State where they pose a growing threat to local ecosystems.

The Western Fisheries Research Center (WFRC) research helps uncover the spread and impact of invasive African Clawed Frogs (Xenopus laevis) in Washington. First detected in the U.S. in 1964, African clawed frogs have now made their way to Washington State where they pose a growing threat to local ecosystems.

This is fieldwork from a Chinook salmon egg survival pilot study in the Sacramento River. Egg boxes were placed in the river at different locations to collect data on egg-to-fry survival. Some examples of data collected include water velocity and river flow, gravel temperature, scour and deposition, and sediment type.

A photo of the McCloud arm looking upstream from one of the telemetry deployment sites.

This is Shasta Dam in California. Mitchell Morse and Caitlin Stockwell drove down to Redding, CA to wrap up the Shasta Reservoir fish telemetry project. They worked with California Department of Fish and Wildlife partners to remove 16 submersible acoustic telemetry receivers within the reservoir, and 5 receivers installed on Shasta Dam.

Mitchell Morse and Caitlin Stockwell drove down to Redding, CA to wrap up the Shasta Reservoir fish telemetry project. They worked with California Department of Fish and Wildlife partners to remove 16 submersible acoustic telemetry receivers within the reservoir, and 5 receivers installed on Shasta Dam.

Ramona Rapp is preparing the surgery station where adult Lost River suckers are surgically implanted with acoustic telemetry transmitters. This study is being conducted to understand seasonal survival and habitat use of Lost River suckers in Upper Klamath Lake.

Chris Pullano and Evan Hockett setting out early morning to reconfigure acoustic telemetry receivers on Upper Klamath Lake, Oregon. Receivers were deployed under ice cover all winter to understand winter movements and habitat use by endangered Lost River suckers.

Matt Sholtis, Brian Hayes, and Evan Hockett returning from a rough day on the water, where they retrieved acoustic telemetry receivers that were set under ice cover all winter to track winter movements of endangered Lost River suckers in Upper Klamath Lake, Oregon. 

Sarah Flores presenting her lab's work at the 2025 International Symposium on Fish Parasites in Mérida Yucatán, Mexico. Sarah Flores works with the Western Fisheries Research Center in Seattle, WA to help suckers in the Upper Klamath Lake in Klamath Falls, OR.

Sarah Flores collecting snails from the marshes of Upper Klamath Lake. At the Western Fisheries Research Center, scientists are conducting research on parasites in Upper Klamath Lake, Klamath Falls, OR.

This is a photo of fish pathogenic cercariae collected from intermediate snail hosts. The Western Fisheries Research Center (WFRC) is working to determine the extent of the effects of these parasitic organisms on suckers in Klamath Falls, OR. Top: Diplostomum gavium; Bottom: Bolbophorus sp.

Local snail screening set up in Klamath Falls, OR at the Bureau of Reclamation facility. Five snails per tank on the right and cups with one snail on the left.

This photo shows the California Department of Fish and Wilflife’s screw trap on the lower Shasta River, where Western Fisheries Research Center (WFRC) scientists surgically implant acoustic telemetry tags and passive integrated transponder tags into juvenil Chinook salmon collected at this site.

This is a map of the United States outlining the different Fisheries Commissions and their geographic locations.

This is a landscape photo of the Klamath River with mountains on either side of the photo. The Western Fisheries Research Center is researching the effects of flow management before and after dam removal on juvenile Chinook salmon survival to the ocean. 

In this photo a USGS Biological Science Technician Brittany Graham is surgically implanting an acoustic telemetry tag into a juvenile salmon on the banks of the lower Shasta River. The Western Fisheries Research Center (WFRC) uses fish with acoustic transmitters to track fish movements and estimate survival. This information provides water managers with ro