Kenneth Tiffan
Snake River fall Chinook salmon were listed as “threatened” under the ESA in 1992. My entire career has focused conducting applied research to provide information that would increase our understanding of this unique stock and facilitate recovery efforts.
The work of myself and colleagues from other agencies have produced most of the contemporary information on Snake River fall Chinook salmon.
Research Interests:
The main focus of my work is understanding Snake River fall Chinook salmon life history and ecology to support recovery of this listed stock. Over the years research topics have included migratory behavior, habitat use and quantification, physiology, and feeding ecology of juvenile fish in the Snake and Columbia rivers. Other research areas have included understanding the effects of elevated flows on chum salmon spawning behavior, and investigating recent food web changes to lower Snake River reservoirs.
Professional Experience
1992 to Present – Research Fish Biologist, U.S. Geological Survey, Western Fisheries Research Center, Columbia River Research Laboratory, Cook, WA
Education and Certifications
M.S. 1992. Fishery Biology, Colorado State University, Fort Collins, CO
B.S. 1987. Fishery Biology, Colorado State University, Fort Collins, CO
Science and Products
Snake River fall chinook salmon life history investigations, 2018 annual report
Research, monitoring, and evaluation of emerging issues and measures to recover the Snake River fall Chinook Salmon ESU
Fall Chinook salmon (Oncorhynchus tshawytscha), sand roller (Percopsis transmontana), and smallmouth bass (Micropterus dolomieu) interactions in a Snake River reservoir: A tale of three species
Post‐release predation mortality of age‐0 hatchery‐reared Chinook salmon from non‐native smallmouth bass in the Snake River
Upstream migration and spawning success of Chinook salmon in a highly developed, seasonally warm river system
Migratory behavior and physiological development as potential determinants of life history diversity in fall Chinook Salmon in the Clearwater River
Juvenile Chinook Salmon mortality in a Snake River Reservoir: Smallmouth Bass predation revisited
Smallmouth bass predation on subyearling fall Chinook salmon in Lower Granite Reservoir, 2016–2017
Ecology of the Sand Roller (Percopsis transmontana) in a lower Snake River Reservoir, Washington
Snake River Fall Chinook Salmon life history investigations
Research, monitoring, and evaluation of emerging issues and measures to recover the Snake River Fall Chinook Salmon ESU, 1/1/2016 - 12/31/2016
Building a state-space life cycle model for naturally produced Snake River fall Chinook salmon
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Snake River fall chinook salmon life history investigations, 2018 annual report
The following report is divided into three sections each of which describes work conducted by different project cooperators. Chapter One describes smallmouth bass (Micropterus dolomieu) predation on subyearling fall Chinook salmon (Oncorhynchus tshawytscha) in Lower Granite Reservoir in 2018. Smallmouth bass abundance increased seasonally in shoreline habitats and was highest in the lower reach ofAuthorsKenneth F. Tiffan, Paul M. Chittaro, Brian P. KennedyResearch, monitoring, and evaluation of emerging issues and measures to recover the Snake River fall Chinook Salmon ESU
The portion of the Snake River fall Chinook Salmon Oncorhynchus tshawytscha ESU that spawns upstream of Lower Granite Dam transitioned from low to high abundance during 1992–2018 in association with U.S. Endangered Species Act recovery efforts and other federally mandated actions. This annual report focuses on (1) numeric and habitat use responses by natural- and hatchery-origin spawners, (2) phenAuthorsKenneth Tiffan, Russell Perry, John Plumb, Dalton Hance, Brad Bickford, Tobyn RhodesFall Chinook salmon (Oncorhynchus tshawytscha), sand roller (Percopsis transmontana), and smallmouth bass (Micropterus dolomieu) interactions in a Snake River reservoir: A tale of three species
We studied some of the relationships between federally listed fall Chinook Salmon, Oncorhynchus tshawytscha, endemic Sand Roller, Percopsis transmontana, and non-native Smallmouth Bass, Micropterus dolomieu, in Lower Granite Reservoir on the Snake River. Because of its recent reappearance and population increase, the Sand Rollers could be filling the role of a “native invader” in the reservoir fooAuthorsRulon J. Hemingway, Kenneth F. Tiffan, John M. Erhardt, Tobyn N. Rhodes, Brad K. BickfordPost‐release predation mortality of age‐0 hatchery‐reared Chinook salmon from non‐native smallmouth bass in the Snake River
Release of age‐0 hatchery‐reared fall Chinook salmon, Oncorhynchus tshawytscha(Walbaum), in the Snake River resulted in up to 30‐fold increases in salmon consumption by non‐native smallmouth bass, Micropterus dolomieu Lacepѐde. In an upper river reach, smallmouth bass fed intensively during a release in May, but Chinook salmon consumption returned to pre‐release levels within 1–2 days as hatchery‐AuthorsJohn M. Erhardt, Kenneth F. TiffanUpstream migration and spawning success of Chinook salmon in a highly developed, seasonally warm river system
This review summarizes what is known about the influence of water temperature and velocity on the migration and spawning success of an inland population of Chinook salmon Oncorhynchus tshawytscha. Models are then developed and used to illustrate how migration and spawning success might change if temperatures and velocities increase under a future climate. The illustration shows the potential for mAuthorsWilliam P. Connor, Kenneth F. Tiffan, James A. Chandler, Dennis W. Rondorf, Billy D. Arnsberg, Kelvin C. AndersonMigratory 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. Movement rates and the percentage of radio‐tagged fish that movedAuthorsKenneth F. Tiffan, Tobias J. Kock, William P. Connor, Marshall C. Richmond, William A. PerkinsJuvenile Chinook Salmon mortality in a Snake River Reservoir: Smallmouth Bass predation revisited
Predation by nonnative fishes has been identified as a contributing factor in the decline of juvenile salmonids in the Columbia River basin. We examined the diet composition of Smallmouth Bass Micropterus dolomieu and estimated the consumption and predation loss of juvenile Chinook Salmon Oncorhynchus tshawytscha in Lower Granite Reservoir on the Snake River. We examined 4,852 Smallmouth Bass stomAuthorsJohn M. Erhardt, Kenneth F. Tiffan, William P. ConnorSmallmouth bass predation on subyearling fall Chinook salmon in Lower Granite Reservoir, 2016–2017
Predation by nonnative fishes is one factor that has been implicated in the decline of juvenile salmonids in the Pacific Northwest. Impoundment of much of the Snake and Columbia Rivers has altered food webs and created habitat favorable for species such as smallmouth bass Micropterus dolomieu. Smallmouth bass are common throughout the Columbia River basin and have become the most abundant predatorAuthorsJohn M. Erhardt, Kenneth F. Tiffan, Rulon J. Hemingway, Brad K. Bickford, Tobyn N. RhodesEcology of the Sand Roller (Percopsis transmontana) in a lower Snake River Reservoir, Washington
The Sand Roller (Percopsis transmontana), has not been abundant in the Snake River since it was first found in the system in the 1950s, but its population has apparently increased in recent years. As a result, we initiated a study to better understand its ecology in habitats of Lower Granite Reservoir. From November 2014 to October 2015, Sand Rollers were present along shorelines, with peak abundaAuthorsKenneth F. Tiffan, John M. Erhardt, Tobyn N. Rhodes, Rulon J. HemingwaySnake River Fall Chinook Salmon life history investigations
Predation by nonnative fishes is one factor that has been implicated in the decline of juvenile salmonids in the Pacific Northwest. Impoundment of much of the Snake and Columbia rivers has altered food webs and created habitat favorable for species such as Smallmouth Bass Micropterus dolomieu. Smallmouth Bass are common throughout the Columbia River basin and have become the most abundant predatorAuthorsJohn M. Erhardt, Brad K. Bickford, Rulon J. Hemingway, Tobyn N. Rhodes, Kenneth F. TiffanResearch, monitoring, and evaluation of emerging issues and measures to recover the Snake River Fall Chinook Salmon ESU, 1/1/2016 - 12/31/2016
The portion of the Snake River fall Chinook Salmon Oncorhynchus tshawytscha ESU that spawns upstream of Lower Granite Dam transitioned from low to high abundance during 1992–2016 in association with U.S. Endangered Species Act recovery efforts and other federally mandated actions. This annual report focuses on (1) numeric and habitat use responses by natural- and hatchery-origin spawners, (2) phenAuthorsWilliam P. Connor, Frank L. Mullins, Kenneth F. Tiffan, John M. Plumb, Russell W. Perry, John M. Erhardt, Rulon J. Hemingway, Brad K. Bickford, Tobyn N. RhodesBuilding a state-space life cycle model for naturally produced Snake River fall Chinook salmon
In 1992, Snake River basin fall Chinook salmon (Oncorhynchus tshawytscha) were listed for protection under the U.S. Endangered Species Act (NMFS 1992) and the population remained below 1000 individuals until 2000. Since then, returns from natural production has rebounded to over 20,000 spawners owing to a host of factors including reduced harvest (Peters et al. 2001), stable minimum spawning flowsAuthorsRussell Perry, John Plumb, Kenneth Tiffan, William P. Connor, Thomas D. Cooney, William Young - News