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Fish Science

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Project Leads


Photo of Mara S. Zimmerman, Ph.D., Research Scientist


Research Focus
- Diversity and ecology of anadromous fishes - Stream temperatures, fish distribution and    behavior
- Life cycle monitoring
- Mark-recapture studies

Ph.D., University of Michigan
B.A., Bowdoin College

Contact information:

Mara S. Zimmerman, Ph.D.
Research Scientist

Dr. Zimmerman joined WDFW in 2008. She leads the Fish Ecology and Life Cycle Monitoring Unit in the Fish Science Division. Research in her unit focuses on the life cycle of anadromous fishes and investigates their abundance, diversity, and distribution in tributaries to the lower Columbia River and in rivers on the Washington coast. The goal of this research is to improve understanding of the biology and status of fish populations in the context of ecological processes and human impacts.

Mara is a field biologist at heart with a background in community ecology and fisheries biology. She has conducted research on a diversity of freshwater fauna including crayfish, freshwater mussels, sticklebacks, lake trout, and, most recently, salmon and steelhead. Prior to joining the Washington Department of Fish and Wildlife, she worked as a biologist for the North Carolina Wildlife Resources Commission, a graduate student instructor for the University of Michigan, and a post-doctoral research associate for the Great Lakes Fishery Commission. In her current position, she enjoys leading science efforts at WDFW and working collaboratively to improve the conservation and management of fish populations in Washington State.

Current Research

  • Patterns and Indicators of Coho Salmon Marine Survival
  • Summer Distribution and Behavior of Fishes in the Chehalis River
  • Freshwater Diversity and Ecology of Chinook Salmon
  • Life History Diversity and Energetics of Steelhead Trout
  • Adaptive Management of Anadromous Fish Reintroductions to the Cowlitz River

Selected Publications

  • Winkowski, J. J., and M. S. Zimmerman. 2017. Summer habitat and movements of juvenile salmonids in a coastal river of Washington State. Ecology of Freshwater Fish.
  • Lamperth, J.S.,T. P. Quinn, and M. S. Zimmerman. 2017. Levels of stored energy but not marine foraging patterns differentiate seasonal ecotypes of wild and hatchery steelhead trout, Oncorhynchus mykiss, returning to the Kalama River, Washington. Canadian Journal of Fisheries and Aquatic Sciences 74: 157-167.
  • Chavarie, L., A.M. Muir, M.S. Zimmerman, S.M. Baillie, M.J. Hansen, N.A. Nate, D.L. Yule, T. Middel, P. Bentzen, and C.C. Krueger. 2016. Challenge to the model of lake charr evolution: shallow and deep-water morphs exist within a small postglacial lake. Biological Journal of the Linnean Society.
  • Zimmerman, M. S., J. R. Irvine, M. O'Neill, J. H. Anderson, C. M. Greene, J. Weinheimer, M. Trudel, and K. Rawson. 2015. Spatial and temporal patterns in smolt survival of wild and hatchery coho salmon in the Salish Sea. Marine and Coastal Fisheries 7:116-134.
  • Zimmerman, M. S., C. Kinsel, E. Beamer, E. J. Connor, and D. E. Pflug. 2015. Abundance, survival, and life history strategies on juvenile migrant Chinook Salmon in the Skagit River, Washington. Transactions of the American Fisheries Society 144:627-641.
  • Muir, A. M., C. R. Bronte, M. S. Zimmerman, H. R. Quinlan, J. D. Glase, and C. C. Krueger. 2014. Ecomorphological diversity of lake trout at Isle Royale, Lake Superior. Transactions of the American Fisheries Society 143:972-987.
  • Hansen, M. J., N. A. Nate, C. C. Krueger, M. S. Zimmerman, H. G. Kruckman, and W. W. Taylor. 2012. Age, growth, survival, and maturity of lake trout morphotypes in Lake Mistassini, Quebec. Transactions of the American Fisheries Society 141:1492-1503.
  • McPhee, M. V., M. S. Zimmerman, T. D. Beacham, B. R. Beckman, J. B. Olsen, L. W. Seeb, and W. D. Templin. 2010. A hierarchical framework to identify influences on Pacific salmon population abundance and structure in the Arctic-Yukon-Kuskokwim region. Pages 1177-1198 in C. C. Krueger and C. E. Zimmerman, editors. Pacific salmon: ecology and management of Western Alaska's populations. American Fisheries Society, Bethesda, Maryland.
  • Zimmerman, M. S., C. C. Krueger, and R. L. Eshenroder. 2007. Morphological and ecological differences between shallow- and deep-water morphotypes in Lake Mistassini, Quebec. Journal of Great Lakes Research 33:156-169.
  • Zimmerman, M. S., C. C. Krueger, and R. L. Eshenroder. 2006. Phenotypic diversity of lake trout in Great Slave Lake: differences in morphology, buoyancy, and habitat depth. Transactions of the American Fisheries Society 135:1056-1067.
  • Zimmerman, M. S. 2007. A field study of brook stickleback morphology: multiple predators and multiple traits. Canadian Journal of Zoology 85:250-260.