The New Lake Michigan Food Web: Establishing links between nearshore food sources and pelagic piscivores.

Grant: # 1550

Grant Amount: $264,772.30

Board Decision Year: 2015

University of Wisconsin-Milwaukee - Great Lakes WATER Institute (Milwaukee)

Great Lakes WATER Institute

Bootsma, Harvey (hbootsma@uwm.edu) 414-382-1717

2015 Ecosystem Health and Sustainable Fish Populations: Ecological and Biological Research to Inform Management - Ecological and biological fisheries research to inform management

Project Summary

With funding from the Great Lakes Fishery Trust, The University of Wisconsin Milwaukee, Great Lakes WATER Institute attempted to better characterize the diets of large-bodied piscivores in Lake Michigan following major ecosystem changes in the past 10-15 years. The project aimed to address the following questions:


  1. Does the ability to utilize nearshore energy sources vary among species?

  2. Within a given species, does the dependence on nearshore energy sources vary with location?

  3. Do spatial and temporal differences in dependence on nearshore energy lead to differences in fish condition?

The project offers important insights into upper food web structure and energy flow of Lake Michigan salmonines diets. The study fills previous knowledge gaps surrounding the diets of brown trout, Coho salmon, and steelhead and provides evidence of how the salmonines have adjusted their diet after ecosystem changes such as the establishment of the dreissenid mussels and the round goby in the Lake Michigan food web. In addition to providing dietary data for certain species, the project also generated the first estimates of niche overlap and diet proportion data for the Lake Michigan piscivore community. The data provide important insight into the upper food web structure and potential interaction among species. The project represents one of the larger databases of fatty acid profiles at the top of a freshwater food web.  

Documents

UWM Great Lakes WATER Institute Final Report
View - GLFT_2015.1550_Final_Report.pdf