Meet Our Dedicated Team!
Dr. Gretchen JA Hansen
Dr. Hansen is an associate professor of Fisheries Ecology in the Fisheries, Wildlife, and Conservation Biology department at the University of Minnesota. Prior to joining the FWCB faculty in 2018, Dr. Hansen worked for five years as a research scientist for the Departments of Natural Resources in Minnesota and Wisconsin.
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2003 Upper Buford Cir; 135 Skok Hall;
Saint Paul, MN 55108
Fish, Wildlife, and Conservation Biology Department
University of Minnesota - Twin Cities
Research Staff
Dr. Michael Verhoeven
Mike is an ecologist working on multiple projects in the lab as the lab manager and staff research scientist. Much of his work involves aggregating landscape scale multi-species survey data and using these to understand how threats like climate change and invasive species impact lake ecology. He also works on understanding the interactions between invasive and native species, and the impacts of inland lake management efforts (like invasive plant control). In his work he tries to incorporate both fundamental and applied ecology, and looks for ways to integrate observational studies and experimental work.
Denver Link, MS
Denver is a researcher who addresses threats to freshwater ecological systems using field and quantitative skills. He earned a MS degree in the Hansen Lab studying zebra mussel impacts on aquatic food webs and fish mercury concentrations. Graduating from St. Olaf College in 2021 with degrees in biology and environmental studies, he enjoys understanding anthropogenic changes in aquatic environments. During his undergraduate studies, Denver spent two summers with the Iowa Department of Natural Resources Fisheries Bureau studying fish populations on the Upper Mississippi River. As a native of Dubuque, Iowa, he appreciates the distinctiveness of the Driftless Area and finds great interest in the intricate interplay among policy, science, and management involved in safeguarding it from land use changes. Outside of the lab, Denver enjoys fishing, supporting the Denver Broncos, and coaching alpine ski racing.
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Postdoctoral Researchers
Dr. Ken Zillig
Ken is a conservation ecophysiologist who uses organismal physiology to understand the effects of environmental change on species and ecosystems. He completed his Ph.D. at the Unversity of California, Davis with Dr. Nann Fangue where his dissertation focused on interpopulation variation in the thermal performance and metabolism of juvenile Chinook salmon [1][2]. His past postdoctoral research focuses on the effects of nutrition on the thermal performance of young salmonids in the California Central Valley. Ken’s work in the Hansen lab will focus on quantifying the oxythermal physiology of Laurentian Coregonids and then integrating that physiological data with population models to understand how rapid environmental change may impact Great Lake populations.
Ken has additionally worked on the effects of food availability on green sturgeon metabolism, the impact of hydropower turbines on white sturgeon passage, the role of physiological performance on trophic interactions [3], the influence of ocean acidification and ocean warming on Antarctic rockcod and the development of swimming respirometers for tropical reef sharks.
His research interests focus on scaling organismal physiology to understand the influence of environmental change on species of commercial and conservation concern. Additionally, he has a passion for the development of novel physiological methodologies that expand our understanding of how fish interact with their environment. Ken is always eager for collaborations or just to chat about fish research and conservation.
Outside of the lab, Ken is an avid birder and a novice, but enthusiastic, woodworker.
Dr. Christopher J Sullivan
Chris is fascinated by actionable fisheries science and ecosystem ecology. Broadly speaking, Chris tries to combine spatial and temporal approaches to understand complex biological and ecological interactions associated with aquatic ecosystems. Chris has published manuscripts focusing on climate change impacts on riverine fish populations, invasion ecology of aquatic species, and critiques of field methods for fishery data collection. Chris attempts to pursue these topics using an adaptive research approach employing field sampling methods, statistical analyses, and simulation modeling, and builds research teams across traditional disciplinary boundaries.
Chris’s work in the Hansen lab will focus on landscape-scale patterns in lake thermal regimes and fish population abundance/growth.
Dr. Cam Mosley
Cam is a fisheries ecologist who is broadly interested in how fish communities respond to human impacts and environmental changes that alter fish habitat availability, sport fish populations, and fish behavior. They completed their Ph.D. at the University of Notre Dame with Dr. Stuart Jones performing several whole lake experiments to examine how recreational fish populations respond to habitat additions[1] and increases in angler effort in northern temperate lakes [2], in addition to a statewide analysis quantifying non-linearity of catch rates for six sport fish in Wisconsin[3].
In the Hansen lab, Cam will be collaborating with Hansen lab members on investigating differences in fish population structure across Midwest fisheries and on an National Science Foundation funded postdoctoral research fellowship in Biology with the aims of examining niche overlap between fish species across thermal guilds, climate-driven species distribution models, and collaborating with the Bell Museum to share their findings with the local community (Award #2410099).
In their free time Cam enjoys a plethora of outdoor activities including but not limited to fishing, camping, hiking, and taking naps on boats. They also enjoy trying new restaurants and walks with their cat Flounder.
Graduate Students
Christopher Rounds - MS (2023), PhD
Christopher is a Hansen lab PhD student in the Conservation Sciences program. He also completed his MS in the Hansen lab. During his MS he studied the optimization of eDNA sampling to detect four priority invasive species in Minnesota lakes. His PhD research focuses on identifying and understanding Midwestern United States fishery bright spots. In his free time, Christopher enjoys playing soccer and recreating on lakes.
Olivia Nyffeler - MS
Olivia is a Master’s student in the Hansen and Waterhouse labs studying drivers of Cisco (Coregonus artedi) Recruitment in Lake Superior. Her project is compiling historical and contemporary datasets from state, tribal and federal agencies working on Lake Superior. She graduated from the University of Wisconsin Madison in 2021 with a degree in Conservation Biology, Psychology, and a certificate in Environmental Studies. During her time there, she worked for the Center for Limnology on a whole lake maniuplation, removing bass and sunfish near Trout Lake Station. In her free time, Olivia enjoys walking her dogs Louie and Atlas, going on long bike rides, or reading good books.
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Grace Hemmelgarn - MS
Grace is a Master's student in the Hansen lab studying the relationships between zooplankton and fish communities and how zooplankton remains in sediment cores can be used to reconstruct historical fish communities. She graduated from Allegheny College in 2022 with a degree in Environmental Science & Sustainability and minors in Biology and Spanish, where she studied dispersal mechanisms of juvenile invasive Round Goby in a lotic system with Dr. Casey Bradshaw-Wilson. Grace has also worked on Lake Trout age estimation to update population parameters in Lake Champlain at the University of Vermont with Dr. Ellen Marsden. She studied environmental science and climate change in antarctic and sub-antarctic climates in Ushuaia, Argentina through the School for International Training where she investigated the diet of South American Sea Lions in the Beagle Channel. In her free time, Grace loves to ride horses, travel, and explore the outdoors.
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Undergraduate Technicians
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Jack Abel
Jack is an undergraduate research technician in the Hansen lab, pursuing a major in Ecology, Evolution, and Behavior, and a minor in Marine Biology within CBS. As a sophomore, he spent the summer as a field and lab assistant at Trout Lake Research Station in northern Wisconsin, working on the walleye Bright Spots project. Jack joined the Hansen lab as a freshman in the spring of 2023, and is deeply interested in the effects of climate change on fish population behavior. Outside of the lab, he enjoys bass fishing, camping, and running.
Alumni
Mayra Velasquez - MS (2023)
Role: Master’s Student
Tristan Blechinger
Roles: Field & lab technician
Nikayla Barnes
Graduated - UMNTC Spring 2023
Major:
Minor:
Role: Field & lab technician
Amanda Van Pelt
Graduated: UMNTC - Spring 2022
Major: Ecology, Evolution, and Behavior
Minor: Environmental Science, Policy, and Management
Role: Field & lab technician
Leah Stern
Graduated: Macalester College - Spring 2021
Major: Biology
Role: Field & lab technician
Nicole Campagnola
Senior at Hopkins High School
Role: Step-Up Intern
Ashley LaRoque
Graduated: UMNTC - Spring 2021
Major: Ecology, Evolution, and Behavior
Minors: German and Marine Biology
Role: Field & lab technician
Jonah Bacon
Graduated: UMNTC - Spring 2021
Major: Ecology, Evolution, and Behavior
Minor: Marine Biology
Role: Field & lab technician
Naomi Blinick
Graduated: UMNTC - Fall 2021
Role: Master’s candidate (Jan. 2022)
Claire Rude
Graduated: UMNTC - Spring 2020
Majors: Fisheries, Wildlife & Conservation Biology, and Environmental Sciences, Policy & Management
Role: Field & lab technician
