Using size spectrum modeling to inform ecosystem management of the Great Lakes

Session: Cross-lake Comparisons: Frameworks for Understanding Ecosystem Change

Thomas Evans, Cornell University, thomas.mark.evans@gmail.com
James Watkins, Cornell University, jmw237@cornell.edu
Zachary S, Wisconsin Department of Natural Resources, Zachary.Feiner@wisconsin.gov
Doran Mason, NOAA Great Lakes Environmental Research Lab, Doran.Mason@noaa.gov
Lars Rudstam, Cornell University Bio Field Station, Dept. of Natural Resources, rudstam@cornell.edu

Abstract

Understanding the productivity of Great Lakes and their capacity to support fishes is an important goal of managers. However, the Great Lakes are too large and resources too limited to sample all species-specific components of the food web. There is a need to develop a holistic food web model which relies on only a few parameters. Theory and empirical analysis have shown that aquatic systems can be resolved as a function of organismal body size and their density; larger individuals prey upon smaller individuals but exhibit slower life histories. As a result, complex food webs can be represented using relatively simple models (i.e., size spectrum modeling; SSM) to elucidate energy flows. Size and density data are routinely collected for a broad range of organisms throughout the Great Lakes, opening the possibility of using SSM across the Great Lakes with no additional cost for data collection. To date SSM has not been widely applied in the Great Lakes, and even when used only a single lake and a relatively modest number of years (one or two) were examined. The present work will investigate whether SSM is suitable for broad use in the Great Lakes by comparing data from all lakes through multiple