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Ryan's research interests include juvenile salmon passage and survival at hydroelectric dams using acoustic and radio telemetry, operating radio telemetry equipment to monitor movements of adult salmon, developing and refining standard operating procedures for surgical implantation of transmitters, and training others in surgical implantation of transmitters.
Ryan is currently working in the Klamath River Basin studying survival of juvenile Chinook salmon migrating through reaches known to have Ceratomyxa Shasta. Ryan is also working on acoustic telemetry studies monitoring movements of Lost River and shortnose suckers in Upper Klamath Lake.
Ryan has previously studied urbanization effects on forage fish in Puget Sound (Coastal Habitats in Puget Sound) and evaluated BioAcoustic fish fence in the Sacramento River.
Ryan Tomka retrieves an acoustic telemetry receiver from the lower Columbia River estuary. During the 2025 field season, researchers deployed acoustic telemetry equipment to track yearling Chinook salmon as they moved through both restored estuarine wetlands and the main Columbia River channel.
Ryan Tomka retrieves an acoustic telemetry receiver from the lower Columbia River estuary. During the 2025 field season, researchers deployed acoustic telemetry equipment to track yearling Chinook salmon as they moved through both restored estuarine wetlands and the main Columbia River channel.
Chris Pullano and Ryan Tomka load acoustic telemetry receives on to boat in lower Columbia River estuary. Field work was recently completed for the first year of a study to better understand how young salmon use restored habitats in the Lower Columbia River Estuary.
Chris Pullano and Ryan Tomka load acoustic telemetry receives on to boat in lower Columbia River estuary. Field work was recently completed for the first year of a study to better understand how young salmon use restored habitats in the Lower Columbia River Estuary.
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.
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.
Collin Smith and Georgia Martin are inserting passive integrated transponders in juvenile Chinook Salmon at Fall Creek Hatchery, California to track their movements. Data are collected for each fish, including length, weight, and the individual number of the inserted tag.
Collin Smith and Georgia Martin are inserting passive integrated transponders in juvenile Chinook Salmon at Fall Creek Hatchery, California to track their movements. Data are collected for each fish, including length, weight, and the individual number of the inserted tag.
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 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.
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
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
USGS, Western Fisheries Research Center scientist tagging an invasive silver carp with an acoustic transmitter to evaluate the effectiveness of a BioAcoustic Fish Fence (BAFF) to deter upstream migration of invasive carp at Barkley Lock and Dam, Kentucky in October 2022.
USGS, Western Fisheries Research Center scientist tagging an invasive silver carp with an acoustic transmitter to evaluate the effectiveness of a BioAcoustic Fish Fence (BAFF) to deter upstream migration of invasive carp at Barkley Lock and Dam, Kentucky in October 2022.
Sockeye salmon preparing to spawn upstream of Cle Elum Dam, Washington.
Sockeye salmon preparing to spawn upstream of Cle Elum Dam, Washington.
Ryan Tomka retrieves an acoustic telemetry receiver from the lower Columbia River estuary. During the 2025 field season, researchers deployed acoustic telemetry equipment to track yearling Chinook salmon as they moved through both restored estuarine wetlands and the main Columbia River channel.
Ryan Tomka retrieves an acoustic telemetry receiver from the lower Columbia River estuary. During the 2025 field season, researchers deployed acoustic telemetry equipment to track yearling Chinook salmon as they moved through both restored estuarine wetlands and the main Columbia River channel.
Chris Pullano and Ryan Tomka load acoustic telemetry receives on to boat in lower Columbia River estuary. Field work was recently completed for the first year of a study to better understand how young salmon use restored habitats in the Lower Columbia River Estuary.
Chris Pullano and Ryan Tomka load acoustic telemetry receives on to boat in lower Columbia River estuary. Field work was recently completed for the first year of a study to better understand how young salmon use restored habitats in the Lower Columbia River Estuary.
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.
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.
Collin Smith and Georgia Martin are inserting passive integrated transponders in juvenile Chinook Salmon at Fall Creek Hatchery, California to track their movements. Data are collected for each fish, including length, weight, and the individual number of the inserted tag.
Collin Smith and Georgia Martin are inserting passive integrated transponders in juvenile Chinook Salmon at Fall Creek Hatchery, California to track their movements. Data are collected for each fish, including length, weight, and the individual number of the inserted tag.
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 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.
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
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
USGS, Western Fisheries Research Center scientist tagging an invasive silver carp with an acoustic transmitter to evaluate the effectiveness of a BioAcoustic Fish Fence (BAFF) to deter upstream migration of invasive carp at Barkley Lock and Dam, Kentucky in October 2022.
USGS, Western Fisheries Research Center scientist tagging an invasive silver carp with an acoustic transmitter to evaluate the effectiveness of a BioAcoustic Fish Fence (BAFF) to deter upstream migration of invasive carp at Barkley Lock and Dam, Kentucky in October 2022.
Sockeye salmon preparing to spawn upstream of Cle Elum Dam, Washington.
Sockeye salmon preparing to spawn upstream of Cle Elum Dam, Washington.