Timothy P O'Brien


I spent my formative years exploring the outdoors, particularly the lakes and streams of Michigan. I was always interested in freshwater environments and the fish that made their homes there. These early experiences impelled me to pursue the study of fish biology and ecology. 

While pursuing my undergraduate degree at the University of Michigan, I began working for USGS at the Great Lakes Science Center in 2003. I began a project studying deepwater sculpin Myoxocephalus thompsonii diets in Lake Huron and was eager to contribute to our understanding of this enigmatic native species. Early on in my career I also learned larval fish identification and became interested in larval fish ecology. Ultimately, I began working in support of the large vessel fish assessment program where most of my work is now focused. While working as a fisheries technician I had the opportunity to return to school to study fishery science and in 2010 I completed a Master of Science degree at Michigan State University studying rainbow smelt Osmerus mordax population dynamics in Lake Huron.

I am involved with both technical and programmatic aspects of the Deepwater Fisheries program:

Supervise a team of technicians supporting ecosystem and fishery studies.

Project lead for the Lake Huron acoustics program where I am responsible for leading a team to carry out a large-scale integrated trawl and acoustics survey of pelagic fishes in Lake Huron.

Large vessel coordinator for fishery research vessels on Lake Huron and Michigan, assist Branch Chief with managing, scheduling, and staffing the GLSC large vessel program.

Oversee fish aging laboratory.



M.S.  2010. Fisheries and Wildlife.  Michigan State University, Department of Fisheries and Wildlife

B.S.  2004. Resource Ecology and Management.  The University of Michigan, School of Natural Resources and Environment



Thompson, P.A., E.F. Roseman, K.M. Keeler, T.P. O’Brien, and D.A. Bowser. 2017. Continued feeding on Diporeia by deepwater sculpin in Lake Huron. Environmental Biology of Fishes. doi: 10.1007/s10641-016-0568-8.

Prichard, C.G., E.F. Roseman, K.M. Keeler, T.P. O’Brien, S.C. Riley. 2016. Large-scale changes in Bloater Coregonus hoyi growth and condition in Lake Huron. Trans Amer Fish Soc. 145:1241-1251.

Duan, Y.J., C.P. Madenjian, C.X. Xie, J.S. Diana, T.P. O’Brien, Y.M. Zhao, J.X. He, S.A. Farha, and B. Huo. 2016. Age and Growth of Round Gobies in Lake Huron: implications for food web dynamics. Journal of Great Lakes Research 42(6): 1443-1451.  

Huo, B., C.P. Madenjian, C.X. Xie, Y. Zhao, T.P. O’Brien, and S. J. Czesny. 2014. Age and growth of round gobies in Lake Michigan, with preliminary morality estimation. Journal of Great Lakes Research 40 (3) 712:720

Pritt, J.J., E.F. Roseman, and T.P.O’Brien2014. Mechanisms driving recruitment variability in fishes: comparisons between the Laurentian Great Lakes and marine systems. ICES Journal of Marine Science 71 (8): 2252-2267.

O’Brien, T.P., W.W. Taylor, E.F. Roseman, C.P. Madenjian, and S.C. Riley. 2014. Ecological factors affecting recruitment of rainbow smelt in Lake Huron, 1976-2010. Transactions of the American Fisheries Society 143:784-795.   

Roseman, E.F., and T.P. O’Brien. 2013. Spatial distribution of pelagic fish larvae in the northern main basin of Lake Huron. Journal of Aquatic Ecosystem Health and Management 16(3):311-321.

George, E., E.F. Roseman, B.M. Davis, and T.P. O’Brien.  2013.  Feeding ecology of pelagic larval burbot Lota lota in northern Lake Huron, Michigan.  Transactions of the American Fisheries Society 142:1716-1723.

O’Brien, T.P., W.W. Taylor, A.S. Briggs, and E.F. Roseman.  2012.  Influence of water temperature on rainbow smelt spawning and early life history dynamics in St. Martin Bay, Lake Huron.  Journal of Great Lakes Research 38:776-785. 

Warner, D.M., R.M. Claramunt, J.S. Schaeffer, D.L. Yule, T.R. Hrabik, B. Pientka, L.G. Rudstam, J.D. Holuszko, and T.P. O’Brien.  2012.  Relationship between mid-water trawling effort and catch composition uncertainty in two large lakes (Huron and Michigan) dominated by alosines, osmerids, and coregonines.  Fisheries Research 123-124:62-69.

Madenjian, C.P., C. Wang, T.P. O’Brien, M. Holuszko, L. Olgivie, and R.G. Stickel.  2010.  Laboratory evaluation of a walleye (Sander vitreus) bioenergetics model.  Fish Physiology and Biochemistry 36:45-53.

Warner, D.M., J.S. Schaeffer, and T.P. O'Brien.  2009.  The Lake Huron pelagic fish community:  persistent spatial pattern along biomass and species composition gradients.  Canadian Journal of Fisheries and Aquatic Sciences 66:1199-1215. 

O’Brien, T.P, E.F. Roseman, C.S. Kiley, and J.S. Schaeffer.  2009.  Fall diet and bathymetric distribution of deepwater sculpin Myoxocephalus thompsonii in Lake Huron.  Journal of Great Lakes Research 35:464-472.

Roseman, E.F., W. Stott, T.P. O’Brien, S.C. Riley, and J.S. Schaeffer.  2009.  Heritage strain and diet of wild young of year and yearling lake trout in the main basin of Lake Huron.  Journal of Great Lakes Research 35(4):620-626.    

Riley, S.C., E.F. Roseman, S.J. Nichols, T.P.O’Brien, C.S. Kiley, and J.S.   Schaeffer.  2008.  Deepwater demersal fish community collapse in Lake Huron.  Transactions of the American Fisheries Society 137:1879-1890.

Schaeffer, J.S., D.M. Warner, and T.P. O’Brien.  2008.  Resurgence of emerald shiner Notropis atherinoides in the main basin of Lake Huron.  Journal of Great Lakes Research 34:395-403.

Walsh, M.G., A.P. Maloy, and T.P. O’Brien.  2008.  Comparison of rainbow smelt age estimates from fin rays.  North American Journal of Fisheries Management 28:42-49.

Riley, S.C., J.X. He, J.E. Johnson, T.P. O’Brien, and J.S. Schaeffer.  2007.  Evidence of widespread natural reproduction by lake trout in the Michigan waters of Lake Huron.  Journal of Great Lakes Research 33:917-921.

O’Brien, T.  2003.  “Salvelinus confluentus” (On-line), Animal Diversity Web. http://animaldiversity.ummz.umich.edu/site/accounts/information/Salvelin...