Tobias J Kock
I am a research fish biologist at the Columbia River Research Laboratory in Cook, Washington. I began working on fisheries studies in 1998 and my research has focused on Pacific salmon and dams in the Pacific Northwest. My expertise includes the use of telemetry systems to monitor juvenile and adult salmon and steelhead, and I am currently working on the Cowlitz, Willamette, and Yakima rivers.
M.S. 2004. Fisheries Science, University of Idaho, Moscow, ID
B.A. 2000. Biology, Minor in Religion, Pacific Lutheran University, Tacoma, WA
My research interests include the evaluation of dam passage and survival, assessment of fish collection devices, development of fish passage options at high-head dams, reintroduction of salmon and steelhead to areas blocked by dams, and effects of climate change on salmon ecology and dam management. 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 procedures, assessment of dam-passage survival of juvenile salmon, and developing methods to estimate survival of salmon fry in reservoirs.
2002 to Present - 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
Science and Products
Scientific Support of Salmon and Steelhead Reintroductions in Impounded River Basins of the Pacific Northwest
Salmon and steelhead populations in the Pacific Northwest were severely affected by hydropower development that occurred during the first half of the 20th century. Impassable dams were constructed on many rivers throughout the region which prevented returning adult salmonids from accessing important habitats where spawning and rearing historically occurred. In the past two decades...
Responses of hatchery‐ and natural‐origin adult spring Chinook Salmon to a trap‐and‐haul reintroduction program
The construction of impassable dams severely affected many Pacific salmon Oncorhynchus spp. populations, resulting in reintroduction efforts that are now focused on returning anadromous fish to areas located upstream of these dams. A primary strategy for moving adult salmon and steelhead O. mykiss around a dam or multiple dams...Kock, Tobias J.; Perry, Russell W.; Pope, Adam C.; Serl, John D.; Kohn, Mike; Liedtke, Theresa L.
Evaluation of sockeye salmon after passage through an innovative upstream fish-passage system at Cle Elum Dam, Washington, 2017
Executive SummaryThe Bureau of Reclamation (Reclamation) and the Washington State Department of Ecology (Ecology), working with the Yakima River Basin Water Enhancement Project Workgroup (composed of representatives of the Yakama Nation; Federal, State, county, and city governments; environmental organizations; and irrigation districts), developed...Kock, Tobias J.; Evans, Scott D.; Hansen, Amy C.; Perry, Russell W.; Hansel, Hal C.; Haner, Philip V.; Tomka, Ryan G.
Passage survival of juvenile steelhead, coho salmon, and Chinook salmon in Lake Scanewa and at Cowlitz Falls Dam, Cowlitz River, Washington, 2010–16
A multi-year evaluation was conducted during 2010–16 to evaluate passage survival of juvenile steelhead (Oncorhynchus mykiss), Chinook salmon (O. tshawytscha), and coho salmon (O. kisutch) in Lake Scanewa, and at Cowlitz Falls Dam in the upper Cowlitz River Basin, Washington. Reservoir passage survival was evaluated in 2010, 2011, and 2016, and...Liedtke, Theresa L.; Kock, Tobias J.; Hurst, William
Migratory behavior and physiological development as potential determinants of life history diversity in fall Chinook Salmon in the Clearwater River
We studied the influence of behavior, water velocity, and physiological development on the downstream movement of subyearling fall‐run Chinook Salmon Oncorhynchus tshawytscha in both free‐flowing and impounded reaches of the Clearwater and Snake rivers as potential mechanisms that might explain life history diversity in this stock....Tiffan, Kenneth F.; Kock, Tobias J.; Connor, William P.; Richmond, Marshall C.; Perkins, William A.
Synthesis of downstream fish passage information at projects owned by the U.S. Army Corps of Engineers in the Willamette River Basin, Oregon
The U.S. Army Corps of Engineers (USACE) operates the Willamette Valley Project (Project) in northwestern Oregon, which includes a series of dams, reservoirs, revetments, and fish hatcheries. Project dams were constructed during the 1950s and 1960s on rivers that supported populations of spring Chinook salmon (Oncorhynchus tshawytscha), winter...Hansen, Amy C.; Kock, Tobias J.; Hansen, Gabriel S.
Preliminary evaluation of the behavior and movements of adult spring Chinook salmon in the Chehalis River, southwestern Washington, 2014
Recent interest in flood control and restoration strategies in the Chehalis River Basin has increased the need to understand the current status and ecology of spring Chinook salmon (Oncorhynchus tshawytscha). Spring Chinook salmon have the longest exposure of all adult Chinook salmon life histories to the low-flow and high water temperature...Liedtke, Theresa L.; Hurst, William R.; Tomka, Ryan G.; Kock, Tobias J.; Zimmerman, Mara S.
Development of a study design and implementation plan to estimate juvenile salmon survival in Lookout Point Reservoir and other reservoirs of the Willamette Project, western Oregon
Survival estimates for juvenile salmon and steelhead fry in reservoirs impounded by high head dams are coveted data by resource managers. However, this information is difficult to obtain because these fish are too small for tagging using conventional methods such as passive-integrated transponders or radio or acoustic transmitters. We...Kock, Tobias J.; Perry, Russell W.; Monzyk, Fred R.; Pope, Adam C.; Plumb, John M.
Survival of juvenile chinook salmon and coho salmon in the Roza Dam fish bypass and in downstream reaches of the Yakima River, Washington, 2016
Estimates of juvenile salmon survival are important data for fishery managers in the Yakima River Basin. Radiotelemetry studies during 2012–14 showed that tagged juvenile Chinook salmon (Oncorhynchus tshawytscha) that passed through the fish bypass at Roza Dam had lower survival than fish that passed through other routes at the dam. That study...Kock, Tobias J.; Perry, Russell W.; Hansen, Amy C.
Behavior patterns and fates of adult steelhead, Chinook salmon, and coho salmon released into the upper Cowlitz River Basin, 2005–09 and 2012, Washington
A multiyear radiotelemetry evaluation was conducted to monitor adult steelhead (Oncorhynchus mykiss), Chinook salmon (O. tshawytscha), and coho salmon (O. kisutch) behavior and movement patterns in the upper Cowlitz River Basin. Volitional passage to this area was eliminated by dam construction in the mid-1960s, and a reintroduction program began...Kock, Tobias J.; Ekstrom, Brian K.; Liedtke, Theresa L.; Serl, John D.; Kohn, Mike
Benefits of prescribed flows for salmon smolt survival enhancement vary longitudinally in a highly managed river system
The influence of streamflow on survival of emigrating juvenile Pacific salmonids Oncorhynchus spp. (smolts) is a major concern for water managers throughout the northeast Pacific Rim. However, few studies have quantified flow effects on smolt survival, and available information does not indicate a consistent flow–survival...Courter, Ian; Garrison, Thomas; Kock, Tobias J.; Perry, Russell W.; Child, David; Hubble, Joel
Dam operations affect route-specific passage and survival of juvenile Chinook salmon at a main-stem diversion dam
Diversion dams can negatively affect emigrating juvenile salmon populations because fish must pass through the impounded river created by the dam, negotiate a passage route at the dam and then emigrate through a riverine reach that has been affected by reduced river discharge. To quantify the effects of a main-stem diversion dam on juvenile...Perry, Russell W.; Kock, Tobias J.; Couter, Ian I; Garrison, Thomas M; Hubble, Joel D; Child, David B
Angler harvest, hatchery return, and tributary stray rates of recycled adult summer steelhead Oncorhynchus mykiss in the Cowlitz River, Washington
Hatchery ‘recycling’ programs have been used to increase angling opportunities by re-releasing fish into a river after they returned to a hatchery or fish trap. Recycling is intended to increase opportunities for fishermen, but this strategy could affect wild fish populations if some recycled fish remain in the river and interact with...Kock, Tobias J.; Perry, Russell W.; Gleizes, Chris; Dammers, Wolf; Liedtke, Theresa L.
Transporting Fish around Impassable Dams: An Opportunity and Challenge for Reintroductions