What drives variability in fish recruitment and food web dynamics among systems and among years

What drives variability in fish recruitment and food web dynamics among systems and among years?

Mary T. Bremigan

Assistant Professor, Fisheries and Wildlife

Aquatic Ecology and Fisheries Management

I enjoy conducting research that draws upon basic ecological theory to address applied management questions. By investigating how fish populations and aquatic food webs vary along abiotic and biotic gradients, my research seeks to classify aquatic systems (e.g., lakes or reservoirs) that can be managed similarly. In addition, I am interested in identifying the mechanisms that drive fish recruitment, as a function of fish life history strategies and environmental variables. A particular goal of mine is to evaluate how watershed or landscape characteristics affect recruitment of fish species, and in turn influence community structure and food web dynamics. Currently, projects in my lab are integrating field sampling, small-scale experiments, and historic data analysis to generate mechanistic understanding of the processes regulating fish recruitment and food web dynamics in several midwestern systems. In Ohio reservoirs, we are evaluating the extent to which reservoir productivity and watershed characteristics can explain variability among reservoirs in recruitment of gizzard shad. In turn, we are evaluating the implications of variable gizzard shad recruitment for sport fish recruitment and reservoir nutrient dynamics. This project has several collaborators from universities in Ohio, as well as Dr. Pat Soranno here at MSU. Also in collaboration with Dr. Soranno, we are evaluating the indirect effects of selective, whole-lake herbicide control of Eurasian watermilfoil, an exotic macrophyte, on littoral lake food webs, with emphasis on recruitment of bluegill and largemouth bass. The newest projects in my labs are (1) integrating historic data sets, collected by the Fisheries Division of the Michigan Department of Natural Resources, with landscape and historic weather data to quantify the extent to which fish growth rates and year class strength vary among lakes (along abiotic and biotic gradients) and among years, and (2) evaluating the effects of artificial structures, placed in impoundments along the Au Sable River, MI, on fish populations.

Selected Publications

Bremigan, M.T. and R.A. Stein. 1994. Gape-dependent larval foraging and zooplankton size: implications for fish recruitment across systems. Canadian Journal of Fisheries and Aquatic Sciences 51:913-922.

Stein, R.A., M.T. Bremigan, and J.M. Dettmers. 1996. Understanding reservoir systems with experimental tests of ecological theory: a prescription for successful management. Pages 6-22 in L.E. Miranda and D.R. DeVries, editors. Multidimensional Approaches to Reservoir Fisheries Management. American Fisheries Society Symposium 16.

Bremigan, M.T. and R.A. Stein. 1997. Experimental assessment of the influence of zooplankton size and density on gizzard shad recruitment. Transactions of the American Fisheries Society 126:622-637.

Schaus, M.H., M.J. Vanni, T.E. Wissing, M.T. Bremigan, J.E. Garvey, and R.A. Stein. 1997. Nitrogen and phosphorus excretion by detritivorous gizzard shad in a reservoir ecosystem. Limnology and Oceanography 42:1386-1397.

DeVries, D.R., M.T. Bremigan, and R.A. Stein. 1998. Prey selection by larval crappie and larval gizzard shad: the importance of gape limitation and comparison between northern lakes and southern reservoirs. Transactions of the American Fisheries Society 127:1040-1050.

Bremigan, M. T. and R. A. Stein. 1999. Larval gizzard shad success, juvenile effects, and reservoir productivity: toward a framework for multi-system management. Transactions of the American Fisheries Society 128:1106-1124.