Tobias J Kock
I am a Supervisory Research Fish Biologist at the Columbia River Research Laboratory, Cook, WA. I began working on fisheries studies in 1998. My research has focused on Pacific salmon, dams and ecology in the Pacific Northwest. My expertise includes the use of telemetry systems to monitor juvenile and adult salmon and steelhead. I currently work on the Columbia, Willamette, and Yakima Rivers.
My research team conducts investigations into dam passage and survival for juvenile and adult Pacific salmon, assesses fish collection and passage devices, researches the ecological effects of high-head dams and reservoirs on anadromous fish, and evaluates various aspects of salmon and steelhead reintroductions upstream of impassable dams. I am currently working on studies that evaluate the effects of flow management on juvenile salmon survival, the responses of adult salmon and steelhead to trap-and-haul, assessment of dam-passage survival of juvenile salmon, and developing methods to estimate survival of salmon fry in reservoirs. My research is highly collaborative. I work closely with Tribal, State and Federal partners to provide unbiased science for use by a diverse group of stakeholders in several watersheds in the western United States.
Professional Experience
2016-Present – Supervisory Research Fish Biologist, U.S. Geological Survey, Western Fisheries Research Center, Columbia River Research Laboratory, Cook, WA
2002 to 2016 - Fish Biologist, U.S. Geological Survey, Western Fisheries Science Center, Columbia River Research Laboratory, Cook, WA
2000-2002 - Graduate Student, University of Idaho, Moscow, ID
1998-2000 - Biological Science Technician, University of Idaho and U.S. Geological Survey
Education and Certifications
M.S. 2004. Fisheries Science, University of Idaho, Moscow, ID
B.A. 2000. Biology, Minor in Religion, Pacific Lutheran University, Tacoma, WA
Affiliations and Memberships*
American Fisheries Society
AFS-BES/ASCE-EWRI Joint Committee on Fisheries Engineering and Science (Webinar Task Group Member)
Science and Products
Behavior and movement of adult summer steelhead following collection and release, lower Cowlitz River, Washington, 2012--2013
Downstream movement of fall Chinook salmon juveniles in the lower Snake River reservoirs during winter and early spring
Evaluation of stream flow effects on smolt survival in the Yakima River basin, Washington
Elevated streamflows increase dam passage by juvenile coho salmon during winter: Implications of climate change in the Pacific Northwest
Behavior and passage of juvenile salmonids during the evaluation of a behavioral guidance structure at Cowlitz Falls Dam, Washington, 2011
Evaluation of angler effort and harvest of rainbow trout (Oncorhynchus mykiss), Lake Scanewa, Washington, 2010
Analysis of dam-passage survival of yearling and subyearling Chinook salmon and juvenile steelhead at The Dalles Dam, Oregon, 2010
Behavior and movement of formerly landlocked juvenile coho salmon after release into the free-flowing Cowlitz River, Washington
Diel behavior of rearing fall Chinook salmon
Quantifying the behavioral response of spawning chum salmon to elevated discharges from Bonneville Dam, Columbia River, USA
Chum salmon Oncorhynchus keta that spawn in main-stem habitats below Bonneville Dam on the Columbia River, USA, are periodically subjected to elevated discharges that may alter spawning behaviour. We investigated behavioural responses of spawning chum salmon to increased water velocities associated with experimental increases in tailwater elevation using acoustic telemetry and a dual-frequency ide
Water velocity, turbulence, and migration rate of subyearling fall Chinook salmon in the free-flowing and impounded Snake River
Behavioural thermoregulation by subyearling fall (autumn) Chinook salmon oncorhynchus tshawytscha in a reservoir
Science and Products
- Science
- Multimedia
- Publications
Filter Total Items: 66
Behavior and movement of adult summer steelhead following collection and release, lower Cowlitz River, Washington, 2012--2013
Executive SummaryHistorically, adult summer steelhead Oncorhynchus mykiss returning to hatcheries on the lower Cowlitz River were sometimes transported and released in the river (recycled) to provide additional angling opportunity for the popular sport fishery in the basin. However, this practice has not been used in recent years because of concerns associated with interactions between hatchery fiAuthorsTobias J. Kock, Theresa L. Liedtke, Brian K. Ekstrom, Dennis W. Rondorf, Chris Gleizes, Wolf Dammers, Scott Gibson, Jamie MurphyDownstream movement of fall Chinook salmon juveniles in the lower Snake River reservoirs during winter and early spring
We conducted a 3-year radiotelemetry study in the lower Snake River to (1) determine whether juvenile fall Chinook salmon Oncorhynchus tshawytscha pass dams during winter, when bypass systems and structures designed to prevent mortality are not operated; (2) determine whether downstream movement rate varies annually, seasonally, and from reservoir to reservoir; and (3) identify some of the factorsAuthorsKenneth F. Tiffan, Tobias J. Kock, William P. Connor, Frank Mullins, R. Kirk SteinhorstEvaluation of stream flow effects on smolt survival in the Yakima River basin, Washington
Study Summary The influence of stream flow on salmon smolt emigration survival is a topic of widespread management interest. We collected smolt survival data to inform flow management decisions in the Yakima Basin. The Yakima River watershed drains the eastern slopes of the Cascade Mountain Range in central Washington State. The upper basin is comprised of two major tributaries–the Naches River anAuthorsCourter, Garrison, Tobias J. Kock, Russell W. PerryElevated streamflows increase dam passage by juvenile coho salmon during winter: Implications of climate change in the Pacific Northwest
A 4-year evaluation was conducted to determine the proportion of juvenile coho salmon Oncorhynchus kisutch passing Cowlitz Falls Dam, on the Cowlitz River, Washington, during winter. River and reservoir populations of coho salmon parr were monitored using radiotelemetry to determine if streamflow increases resulted in increased downstream movement and dam passage. This was of interest because fishAuthorsTobias J. Kock, Theresa L. Liedtke, Dennis W. Rondorf, John D. Serl, Mike Kohn, Karin A. BumbacoBehavior and passage of juvenile salmonids during the evaluation of a behavioral guidance structure at Cowlitz Falls Dam, Washington, 2011
Executive Summary A radiotelemetry evaluation was conducted during April–October 2011 to describe movement patterns, forebay behavior, and passage of juvenile steelhead, coho salmon, and Chinook salmon at Cowlitz Falls Dam, Washington. The primary focus of the study was to describe fish behavior near a behavioral guidance structure (BGS) and floating surface collector (FSC) deployed upstream of CoAuthorsTobias J. Kock, Theresa L. Liedtke, Brian K. Ekstrom, Ryan G. Tomka, Dennis W. RondorfEvaluation of angler effort and harvest of rainbow trout (Oncorhynchus mykiss), Lake Scanewa, Washington, 2010
A creel evaluation was conducted in Lake Scanewa, a reservoir on the Cowlitz River, to monitor catch rates of rainbow trout (Oncorhynchus mykiss) and determine if the trout fishery was having negative impacts on juvenile anadromous salmon (Oncorhynchus spp.) in the system. The trout fishery, which is supported by releases of 20,000 fish (2 fish per pound) per year from June to August, was developeAuthorsTheresa L. Liedtke, Tobias J. Kock, Brian K. Ekstrom, Ryan G. Tomka, Dennis W. RondorfAnalysis of dam-passage survival of yearling and subyearling Chinook salmon and juvenile steelhead at The Dalles Dam, Oregon, 2010
We performed a series of analyses of mark-recapture data from a study at The Dalles Dam during 2010 to determine if model assumptions for estimation of juvenile salmonid dam-passage survival were met and if results were similar to those using the University of Washington's newly developed ATLAS software. The study was conducted by the Pacific Northwest National Laboratory and used acoustic telemetAuthorsJohn W. Beeman, Tobias J. Kock, Russell W. Perry, Steven G. SmithBehavior and movement of formerly landlocked juvenile coho salmon after release into the free-flowing Cowlitz River, Washington
Formerly landlocked Coho Salmon (Oncorhynchus kisutch) juveniles (age 2) were monitored following release into the free-flowing Cowlitz River to determine if they remained in the river or resumed seaward migration. Juvenile Coho Salmon were tagged with a radio transmitter (30 fish) or Floy tag (1050 fish) and their behavior was monitored in the lower Cowlitz River. We found that 97% of the radio-tAuthorsTobias J. Kock, Julie A. Henning, Theresa L. Liedtke, Ida M. Royer, Brian K. Ekstrom, Dennis W. RondorfDiel behavior of rearing fall Chinook salmon
In fisheries science, habitat use is often inferred when fish are sampled or observed in a particular location. Physical habitat is typically measured where fish are found, and thus deemed important to habitat use. Although less common, a more informative approach is to measure or observe fish behavior within given habitats to more thoroughly assess their use of those locations. While this approacAuthorsKenneth F. Tiffan, Tobias J. Kock, Joseph J. SkalickyQuantifying the behavioral response of spawning chum salmon to elevated discharges from Bonneville Dam, Columbia River, USA
Chum salmon Oncorhynchus keta that spawn in main-stem habitats below Bonneville Dam on the Columbia River, USA, are periodically subjected to elevated discharges that may alter spawning behaviour. We investigated behavioural responses of spawning chum salmon to increased water velocities associated with experimental increases in tailwater elevation using acoustic telemetry and a dual-frequency ide
AuthorsK.F. Tiffan, C. A. Haskell, T.J. KockWater velocity, turbulence, and migration rate of subyearling fall Chinook salmon in the free-flowing and impounded Snake River
We studied the migratory behavior of subyearling fall Chinook salmon Oncorhynchus tshawytscha in free-flowing and impounded reaches of the Snake River to evaluate the hypothesis that velocity and turbulence are the primary causal mechanisms of downstream migration. The hypothesis states that impoundment reduces velocity and turbulence and alters the migratory behavior of juvenile Chinook salmon asAuthorsKenneth F. Tiffan, Tobias J. Kock, Craig A. Haskell, William P. Connor, R. Kirk SteinhorstBehavioural thermoregulation by subyearling fall (autumn) Chinook salmon oncorhynchus tshawytscha in a reservoir
This study investigated behavioural thermoregulation by subyearling fall (autumn) Chinook salmon Oncorhynchus tshawytscha in a reservoir on the Snake River, Washington, U.S.A. During the summer, temperatures in the reservoir varied from 23?? C on the surface to 11?? C at 14 m depth. Subyearlings implanted with temperature-sensing radio transmitters were released at the surface at temperatures >20?AuthorsK.F. Tiffan, T.J. Kock, W.P. Connor, R.K. Steinhorst, D.W. Rondorf - News
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