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Ian Jezorek

I am a Fisheries Biologist working extensively with small stream and river environments with an emphasis on salmonids, both resident and anadromous. Research includes population, behavior and responses to restoration actions including dam removals. Research tools include snorkeling, electrofishing, and trapping to count and capture fish.

I have focused much on PIT tagging and radio tagging of juvenile and adult salmonids.  I have been involved in design, construction, deployment, and operation of many instream PIT-tag interrogation systems.

I am currently involved with studies focusing on steelhead populations, life histories, habitat, and limiting factors in the Wind River, WA as part of a multi-agency effort to restore steelhead populations in the Wind River.  A portion of the Wind River work has focused on interaction between juvenile steelhead an introduced run of hatchery spring Chinook salmon. A current focus of work in the Wind River and the White Salmon River, WA is on assessing salmonid population response to dam removal, which has occurred in both watersheds. Much data on salmonid ecology and life-histories is gathered through tagging fish with Passive Integrated Transponder (PIT) tags. Instream PIT tag detection systems are a tool we have employed in many watersheds and continue to do so in several local watersheds.

Professional Experience

  • 1997 to Present - Fish Biologist, U.S. Geological Survey, Western Fisheries Research Center, Columbia River Research Laboratory, Cook, WA

  • 1996-1997 - Biologist 1, Johnson Controls World Services Inc. Stationed at Columbia River Research Laboratory, Cook, WA

  • 1995.  Biological Aid, Oregon Department of Fish and Wildlife, Research Division, The Dalles, OR

  • 1994.  Fisheries Technician, USDA Forest Service, Ochoco Ranger Station, Prineville, OR

  • 1993.  Biological Aid, Idaho Department of Fish and Game, Lewiston, ID

Education and Certifications

  • B.S. 1992. Fishery Science, Virginia Polytechnic Institute and State University

Science and Products

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Clearing snow from solar panels

Salmonid Population and Life History Research in Tributary Stream and River Habitats and Response to Dam Removal

Juvenile anadromous salmonids all spend some portion of their lives in freshwater. This time may vary from days to years depending upon species and run. Spring Chinook Salmon and Coho salmon generally spend one year in freshwater and Steelhead may spend up to five years in freshwater prior to beginning their journey to sea. Several projects at WFRC – CRRL are investigating populations, life...
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Ecosystems Mission Area, Invasive Species Program (unpublished), Status and Trends Program (unpublished), Western Fisheries Research Center, Columbia River Research Laboratory (CRRL)
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Salmonid Population and Life History Research in Tributary Stream and River Habitats and Response to Dam Removal

Juvenile anadromous salmonids all spend some portion of their lives in freshwater. This time may vary from days to years depending upon species and run. Spring Chinook Salmon and Coho salmon generally spend one year in freshwater and Steelhead may spend up to five years in freshwater prior to beginning their journey to sea. Several projects at WFRC – CRRL are investigating populations, life...
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A view of the landscape of Rock Creek

Rock Creek Fish Population and Life History Assessment (Washington)

The research conducted by the U.S. Geological Survey, in coordination with the Yakama Nation, is designed to determine stream habitat conditions, fish abundance, and fish life history characteristics such as movement, growth, and distribution.
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Ecosystems Mission Area, Fisheries Program (unpublished), Western Fisheries Research Center, Columbia River Research Laboratory (CRRL)
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Rock Creek Fish Population and Life History Assessment (Washington)

The research conducted by the U.S. Geological Survey, in coordination with the Yakama Nation, is designed to determine stream habitat conditions, fish abundance, and fish life history characteristics such as movement, growth, and distribution.
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A view of White Creek

Steelhead Life History Study in White Creek on the Yakama Nation Reservation

Fishery biologists from the U.S. Geological Survey have teamed with fishery biologists from the Yakama Nation to conduct a life history study of the juvenile steelhead using small electronic tags.
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Ecosystems Mission Area, Fisheries Program (unpublished), Western Fisheries Research Center, Columbia River Research Laboratory (CRRL)
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Steelhead Life History Study in White Creek on the Yakama Nation Reservation

Fishery biologists from the U.S. Geological Survey have teamed with fishery biologists from the Yakama Nation to conduct a life history study of the juvenile steelhead using small electronic tags.
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Scientist working on White Salmon River screw trap
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Filter Total Items: 41

Juvenile salmonid monitoring to assess natural recolonization following removal of Condit Dam on the White Salmon River, Washington, 2016–21

Condit Dam was removed from river kilometer (rkm) 5.3 of the White Salmon River, Washington, in 2011 and 2012 after blocking upstream passage of anadromous fish for nearly 100 years. The dam removal opened habitat upstream and improved habitat downstream with addition of cobble and gravel to a reach depauperate of spawning and rearing habitat. We assessed juvenile anadromous salmonid abundance and

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Ecosystems Mission Area, Fisheries Program (unpublished), Species Management Research Program, Western Fisheries Research Center

Hybridization between historically allopatric Chinook salmon populations in the White Salmon River, WA

Chinook Salmon spawning in the White Salmon River consist of members of three historically distinct populations: spring Chinook Salmon, Tule fall Chinook Salmon and Upriver Bright (URB) fall Chinook Salmon. Previous work examined juveniles captured in 2006-2008 and reported hybridization between introduced URBs, and the native threatened Tules. Recent increases in nearby hatchery URB release numbe
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Ecosystems Mission Area, Fisheries Program (unpublished), Species Management Research Program, Western Fisheries Research Center, Columbia River Research Laboratory (CRRL)

Wind River Subbasin Restoration annual report of U.S. Geological Survey activities January 2019 through December 2019

No abstract available.
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Ecosystems Mission Area, Fisheries Program (unpublished), Western Fisheries Research Center, Columbia River Research Laboratory (CRRL)

Wind River subbasin restoration: Annual report of US..Geological Survey activities, January 2018 through December 2018

We sampled juvenile wild Steelhead Oncorhynchus mykiss in headwater streams of the Wind River, WA, to characterize populations and investigate life-history metrics, particularly migratory patterns. We used Passive Integrated Transponder (PIT)-tagging and a series of instream PIT-tag interrogation systems (PTISs) to track juveniles. The Wind River subbasin is considered a wild Steelhead refuge by W
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Ecosystems Mission Area, Fisheries Program (unpublished), Western Fisheries Research Center, Columbia River Research Laboratory (CRRL)

A field evaluation of the growth and survival of age-0 Oncorhynchus mykiss tagged with 8-mm passive integrated transponder (PIT) tags

BackgroundIn fish tagging studies, tag size limits the size of fish that can be tagged, the fraction of a population that can be represented, and ultimately inferences that can be made about the study population, particularly when juvenile fish are the subject of interest. Introduction of an 8-mm passive integrated transponder (PIT) reduced the minimum taggable size of fish, but it has not been ev
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Ecosystems Mission Area, Fisheries Program (unpublished), Species Management Research Program, Western Fisheries Research Center, Columbia River Research Laboratory (CRRL)

Wind River subbasin restoration annual report of USGS activities January 2017 through December 2017

We used Passive Integrated Transponder (PIT)-tagging and a series of instream PIT-tag interrogation systems (PTISs) to investigate life-histories, populations, and efficacy of habitat restoration actions for wild Steelhead Oncorhynchus mykiss in the Wind River subbasin, WA. No hatchery Steelhead have been planted in the Wind River subbasin since 1997, and hatchery adults are estimated to be less t
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Ecosystems Mission Area, Fisheries Program (unpublished), Western Fisheries Research Center, Columbia River Research Laboratory (CRRL)

Juvenile salmonid monitoring following removal of Condit Dam in the White Salmon River Watershed, Washington, 2017

Condit Dam, at river kilometer 5.3 on the White Salmon River, Washington, was breached in 2011, and removed completely in 2012, providing anadromous salmonids with the opportunity to recolonize habitat blocked for nearly 100 years. Prior to dam removal, a multi-agency workgroup concluded that the preferred salmonid restoration alternative was to allow natural recolonization. Monitoring would asses
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Ecosystems Mission Area, Fisheries Program (unpublished), Species Management Research Program, Western Fisheries Research Center, Columbia River Research Laboratory (CRRL)

Wind River Subbasin Restoration, Annual report of U.S. Geological Survey activities, January 2016 through December 2016

We used Passive Integrated Transponder (PIT)-tagging and a series of instream PIT-tag interrogation systems (PTISs) to investigate life-histories, populations, and efficacy of habitat restoration actions for steelhead Oncorhynchus mykiss in the Wind River subbasin, WA. Our tagging focused on parr in headwaters areas of the subbasin and our instream readers provided information on movement of these
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Ecosystems Mission Area, Fisheries Program (unpublished), Western Fisheries Research Center, Columbia River Research Laboratory (CRRL)

Juvenile salmonid monitoring in the White Salmon River, Washington, post-Condit Dam removal, 2016

Condit Dam, at river kilometer 5.3 on the White Salmon River, Washington, was breached in 2011 and removed completely in 2012, allowing anadromous salmonids access to habitat that had been blocked for nearly 100 years. A multi-agency workgroup concluded that the preferred salmonid restoration alternative was natural recolonization with monitoring to assess efficacy, followed by a management evalua
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Ecosystems Mission Area, Fisheries Program (unpublished), Species Management Research Program, Western Fisheries Research Center, Columbia River Research Laboratory (CRRL)

Wind River Subbasin Restoration, annual report of U.S. Geological Survey activities: Parr monitoring and instream passive integrated transponder detection, January 1, 2015 – December 31, 2015

We used Passive Integrated Transponder (PIT)-tagging and a series of instream PIT-tag interrogation systems (PTIS) to investigate life-histories, populations, and efficacy of habitat restoration actions for steelhead Oncorhynchus mykiss in the Wind River subbasin, WA. Our tagging focused on parr in headwater areas of the subbasin and our PTISs provide information on movement of these parr, which i
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Ecosystems Mission Area, Fisheries Program (unpublished), Species Management Research Program, Western Fisheries Research Center, Columbia River Research Laboratory (CRRL)

Instream PIT-tag detection system. Report B

Abstract not available 
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Ecosystems Mission Area, Fisheries Program (unpublished), Western Fisheries Research Center

Wind River subbasin restoration: Annual report of U.S. Geological Survey activities January 2014 through December 2014

Executive Summary The Wind River subbasin in southwest Washington State provides habitat for a population of wild Lower Columbia River steelhead Oncorhynchus mykiss, which are listed as threatened under the Endangered Species Act. No hatchery steelhead have been planted in the Wind River subbasin since 1994, and hatchery adults are estimated to be less than one percent of adults in any year (Thoma
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Ecosystems Mission Area, Fisheries Program (unpublished), Western Fisheries Research Center, Columbia River Research Laboratory (CRRL)
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Congratulations to Joe Warren for Winning this Issue’s Photo Contest!

USGS Western Fisheries Research Center (WFRC) Fish Biologist, Joe Warren, is the winner of this issues photo contest. The image shows opening day of...

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