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
Ecology of nonnative Siberian prawn (Palaemon modestus) in the lower Snake River, Washington, USA
Feeding ecology of non-native Siberian prawns, Palaemon modestus (Heller, 1862) (Decapoda, Palaemonidae), in the lower Snake River, Washington, U.S.A.
Survival, growth, and tag retention in age-0 Chinook Salmon implanted with 8-, 9-, and 12-mm PIT tags
Assessing juvenile salmon rearing habitat and associated predation risk in a lower Snake River reservoir
Research, monitoring, and evaluation of emerging issues and measures to recover the Snake River fall Chinook salmon ESU, 1/1/2014 - 12/31/2014
Snake River fall Chinook salmon life history investigations, 1/1/2013 – 12/31/2013
Snake River fall Chinook salmon life history investigations, 1/1/2012 - 12/31/2012: Annual report 2002-032-00
Research, monitoring, and evaluation of emerging issues and measures to recover the Snake River fall Chinook salmon ESU, 1/1/2012 – 12/31/2013: Annual report, 1991-029-00
Prey availability, consumption, and quality contribute to variation in growth of subyearling Chinook Salmon rearing in riverine and reservoir habitats
Estimates of subyearling fall Chinook salmon rearing habitat in Lower Granite reservoir
Evidence for density-dependent changes in growth, downstream movement, and size of Chinook salmon subyearlings in a large-river landscape
Snake River fall Chinook salmon life history investigations: Annual report 2011 (April 2011 - March 2012)
Science and Products
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Filter Total Items: 108
Ecology of nonnative Siberian prawn (Palaemon modestus) in the lower Snake River, Washington, USA
We assessed the abundance, distribution, and ecology of the nonnative Siberian prawn Palaemon modestus in the lower Snake River, Washington, USA. Analysis of prawn passage abundance at three Snake River dams showed that populations are growing at exponential rates, especially at Little Goose Dam where over 464,000 prawns were collected in 2015. Monthly beam trawling during 2011–2013 provided inforAuthorsJohn M. Erhardt, Kenneth F. TiffanFeeding ecology of non-native Siberian prawns, Palaemon modestus (Heller, 1862) (Decapoda, Palaemonidae), in the lower Snake River, Washington, U.S.A.
We used both stomach content and stable isotope analyses to describe the feeding ecology of Siberian prawns Palaemon modestus (Heller, 1862), a non-native caridean shrimp that is a relatively recent invader of the lower Snake River. Based on identifiable prey in stomachs, the opossum shrimp Neomysis mercedis Holmes, 1896 comprised up to 34-55% (by weight) of diets of juvenile to adult P. modestus,AuthorsKenneth F. Tiffan, William HurstSurvival, growth, and tag retention in age-0 Chinook Salmon implanted with 8-, 9-, and 12-mm PIT tags
The ability to represent a population of migratory juvenile fish with PIT tags becomes difficult when the minimum tagging size is larger than the average size at which fish begin to move downstream. Tags that are smaller (e.g., 8 and 9 mm) than the commonly used 12-mm PIT tags are currently available, but their effects on survival, growth, and tag retention in small salmonid juveniles have receiveAuthorsKenneth F. Tiffan, Russell W. Perry, William P. Connor, Frank L. Mullins, Craig Rabe, Doug D NelsonAssessing juvenile salmon rearing habitat and associated predation risk in a lower Snake River reservoir
Subyearling fall Chinook salmon (Oncorhynchus tshawytscha) in the Columbia River basin exhibit a transient rearing strategy and depend on connected shoreline habitats during freshwater rearing. Impoundment has greatly reduced the amount of shallow-water rearing habitat that is exacerbated by the steep topography of reservoirs. Periodic dredging creates opportunities to strategically place spoils tAuthorsKenneth F. Tiffan, James R. Hatten, David A TrachtenbargResearch, monitoring, and evaluation of emerging issues and measures to recover the Snake River fall Chinook salmon ESU, 1/1/2014 - 12/31/2014
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 1992–2014 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, Russell W. Perry, John M. Erhardt, Scott J. St John, Brad K. Bickford, Tobyn N. RhodesSnake River fall Chinook salmon life history investigations, 1/1/2013 – 12/31/2013
Smallmouth bass predation on subyearling fall Chinook salmon was examined in the upper portion of Lower Granite Reservoir during 2013. During the time subyearlings were present in the reservoir, smallmouth bass were collected, their stomach contents removed for diet analysis, and their abundance estimated with mark-recapture techniques. In 2013, the greatest consumption of subyearlings by smallmouAuthorsKenneth F. Tiffan, William P. ConnorSnake River fall Chinook salmon life history investigations, 1/1/2012 - 12/31/2012: Annual report 2002-032-00
Executive Summary a. Fish Population RM&E This annual report describes the data collected and analyses conducted during calendar years 2012-2013 by staff of project 20023200. The USGS contributed only to the predation research and reservoir invertebrate work described in this report and the presentation of their results is consistent with USGS policy guidelines. The USGS is not responsible for theAuthorsKenneth F. Tiffan, Willam P. Connor, Brian J. Bellgraph, Paul M. ChittaroResearch, monitoring, and evaluation of emerging issues and measures to recover the Snake River fall Chinook salmon ESU, 1/1/2012 – 12/31/2013: Annual report, 1991-029-00
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 1992–2014 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 Mullins, Kenneth F. Tiffan, Russell W. Perry, John M. Erhardt, Scott J. St. John, Brad K. Bickford, Tobyn N. RhodesPrey availability, consumption, and quality contribute to variation in growth of subyearling Chinook Salmon rearing in riverine and reservoir habitats
We examined prey availability, prey consumed, and diet energy content as sources of variation in growth of natural fall Chinook Salmon Oncorhynchus tshawytscha subyearlings rearing in riverine and reservoir habitats in the Snake River. Subyearlings in riverine habitat primarily consumed aquatic insects (e.g., Diptera, Ephemeroptera, Trichoptera), of which a high proportion was represented by adultAuthorsKenneth F. Tiffan, John M. Erhardt, Scott J. St. JohnEstimates of subyearling fall Chinook salmon rearing habitat in Lower Granite reservoir
No abstract available.AuthorsKenneth F. Tiffan, James R. HattenEvidence for density-dependent changes in growth, downstream movement, and size of Chinook salmon subyearlings in a large-river landscape
We studied the growth rate, downstream movement, and size of naturally produced fall Chinook Salmon Oncorhynchus tshawytscha subyearlings (age 0) for 20 years in an 8th-order river landscape with regulated riverine upstream rearing areas and an impounded downstream migration corridor. The population transitioned from low to high abundance in association with U.S. Endangered Species Act and other fAuthorsWilliam P. Connor, Kenneth F. Tiffan, John M. Plumb, Christine M. MoffitSnake River fall Chinook salmon life history investigations: Annual report 2011 (April 2011 - March 2012)
Executive Summary Chapter One – This chapter was published in the Transactions of the American Fisheries Society in 2012. We conducted a three-year radiotelemetry study in the lower Snake River to answer the questions: do fall Chinook salmon juveniles pass dams during winter when bypass systems and structures designed to prevent mortality are not operated; does downstream movement rate vary annualAuthorsKenneth F. Tiffan, William P. Connor, Brian J. Bellgraph, Tobias J. Kock, Frank Mullins, R. Kirk Steinhorst, Helena E. Christiansen, Stephen D. McCormick, Lori A. Ortega, Kathleen M. Carter, Evan V. Arntzen, Katherine J.C. Klett, Z. Daniel Deng, Tylor K. Abel, Timothy J. Linley, Valerie I. Cullinan, Scott J. St John, John M. Erhardt, Brad K. Bickford, Amanda Schmidt, Tobyn N. Rhodes - News