The EwE experience from the Laurentian Great Lakes

Dr. Yu-Chun Kao is a biologist at U.S. Geological Survey’s Great Lakes Science Center. His research focuses on using quantitative methods to better understand the causal links between anthropogenic stressors and ecosystem changes. “Anthropogenic stressors” here usually means nutrients, invasive species, and climate change. “Ecosystems” here usually means lakes but can also be other types of inland aquatic ecosystems, such as rivers and wetlands. “Changes” here usually means changes in fisheries resources. Dr. Kao has used Ecopath with Ecosim (EwE) frequently in his research. To date, he has led the development of nine Ecopath models (six with Ecosim) for Saginaw Bay, Lake Huron, Lake Michigan, and Illinois River in the Midwest of USA and Lake Poyang in China.

Starting from around 2010, EwE has been widely used to understand effects of nutrients and invasive species on Great Lakes food webs. To date, EwE models have been developed for all five Great Lakes and a few Ecopath models have been updated to represent a more recent food web. However, despite receiving accolades and recognition from research communities, researchers and managers were still skeptical about using EwE as a management decision-support tool. In this seminar, I will present three case studies showing how EwE models have been used to better understand the food webs across the Great Lakes and discuss our major challenges associated with using this modeling approach.