Department of Biology

B.S., 1993, University of Wisconsin Stevens Point
M.S., 1995, University of Wisconsin Madison
Ph.D., 1999, University of Wisconsin Madison

Office: 11 SSB
Phone: 726-7626

Curriculum vitae

My Google Scholar Page


Aquatic Ecology, Fisheries, Hydroacoustics

My research program examines several aspects of fisheries ecology. Current projects are focused on studying the interactions between exotic and native fishes, the effects of climate change on habitat quality for cold water fishes, nutrient regeneration-translocation by vertically migrating fauna in the food web of Lake Superior and individual based modeling. While this group of topics is diverse, each is important for they are focused on examining the influence of human induced environmental change on aquatic communities.Fish populations are a vital source of revenue for economic interests in sport and commercial fisheries, as well as a vital link in ecosystem processes that influence water quality. Understanding linkages between aquatic species and ecosystems is vital to predicting the effects of changing the natural environment.


Recent Publications

  • Kruger, B.R., Werne, J.P., Branstrator, D.K., Hrabik, T.R., Chikaraishi, Y., Ohkouchi, N., Minor, E.C., 2015. Organic Matter Transfer in Lake Superior’s Food Web: Insights from Bulk and Molecular Stable Isotope and Radiocarbon Analyses. Limnology and Oceanography. doi: 10.1002/lno.10205.
  • Keyler, T*., T.R. Hrabik, and A. Mensinger. 2015. Foraging mechanisms of siscowet (Salvelinus namaycush siscowet) on pelagic prey. In Press. Journal of Great Lakes Research.
  • Olson, K.*, O.P. Jensen and T.R. Hrabik. 2015. Feeding ecology and prey resource partitioning of lenok (Brachymystax lenok) and Baikal grayling (Thymallus arcticus baicalensis) in the Eg and Uur Rivers, Mongolia. In press. Ecology of Freshwater Fish.
  • Lawson, Z.J., J.M. Vander Zanden, C. Smith, E. Heald*, T.R. Hrabik and S.R. Carpenter. 2015. A test of thermal limits: experimental mixing of Crystal Lake, WI to eradicate cold water invasive smelt. Can. J. Fish. Aquat. Sci. 72:926-937.
  • Harrington, K.A., T.R. Hrabik and A. Mensinger. 2015. Visual sensitivity of deep water Lake Superior fishes. Plos one. 10: e0116173.
  • Oliver, S.K.*, D.B. Branstrator, T.R. Hrabik, S. Guildford, R. Hecky. 2015. Zooplankton nutrient recycling in the deep chlorophyll layer of Lake Superior. Can. J. Fish. Aquat. Sci. 72:390-399. DOI: 10.1139/cjfas-2014-0209.
  • Meyers J., D.L. Yule, M.L. Jones, T.D. Ahrenstorff*, T.R. Hrabik, R.M. Claramunt, M.P. Ebener; E.K. Berglund. 2015. Spatial synchrony in cisco recruitment. Fisheries Research. 165:11-21.
  • Gaeta, J., T. R. Hrabik, G.G. Sass, B.M. Roth, G. Hansen, S. Gilbert and J. Vander Zanden. 2015. Dynamics of rainbow smelt under altered predation and fishing mortality. Hydrobiologia 746:433-444.
  • Hrabik, T.R., B.M. Roth and T.D. Ahrenstorff. 2014. Predation risk and prey fish vertical migration in Lake Superior: insights from an individual based model of siscowet (Salvelinus namaycush). Journal of Great Lakes Research 40:730-738.

* Hrabik Graduate Student



  • BIOL 3835 Freshwater Ecology
  • BIOL 4761 Ichthyology
  • BIOL 5805 Fisheries Ecology
  • BIOL 2802 Ecology Lab
  • IBS 8201 Ecological Processes


Current Graduate Student Projects

  • Trevor Keylor (M.S., Integrated Biosciences) (co-advisor w/Mensinger). Thesis – Foraging mechanisms in deepwater fishes in Lake Superior.
  • Matt Pawlawski (M.S., Integrated Biosciences) (co-advisor w/Branstrator). Thesis – Contribution of invasive spiny water flea (Bythotrephes longimanus) to the Lake Superior food web.
  • Ian Harding (M.S., Integrated Biosciences) (co-advisor w/Branstrator). Thesis – Long-term changes in growth and consumption by cisco (Coregonus artedi) in Lake Superior


Recently Completed Graduate Student Projects

  • Samantha Oliver (M.S., Integrated Biosciences )(co-advisor w/Branstrator). Thesis - Nutrietnt regeneration by zooplankton in Lake Superior.
  • Emily Heald (M.S. Integrated Biosciences) (Primary Advisor). Determinants of spatial correlation in pelagic fish and zooplankton distributions).
  • Kirk Olson (M.S., Integerated Biosciences) (Primary Advisor). Thesis – Niche partitioning and diet characteristics of Arctic grayling, Hovsgol grayling and sharp-nosed lenok in Mongolia.


Recent UROP Student Projects

  • Jamie Dobesinski. UROP. Changes in zooplankton with whole lake experimental mixing
  • Marc Sizer.  UROP. Mortality of deepwater Lake Superior fishes
  • Lee Austin. McNair Fellow. Foraging mechanisms of walleye (Sander vitreus).



Fishing, skiing, scuba diving, canoeing, and camping.

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