Assessing Nearshore-Offshore Connectivity in the Lake Michigan Food Web Using Multiple Trophic Indicators
Major Goals and Objectives
- Investigate how ecosystem-wide changes to Lake Michigan affect prey utilization by top predators, using stomach content, fatty acid profiles, and stable isotope ratios
Keywordsecology, fatty acid, food web, stable isotope, trophic
Non-native species introduced through human activities have altered the food web of Lake Michigan. To better understand how these introductions have affected salmon, we examined the diets of salmon caught by anglers throughout Lake Michigan. Some species (Chinook and Coho), relied heavily on Alewife as prey whereas other species (Lake Trout and Rainbow Trout) had more varied diets. Lake Trout diet composition depended on where they were in the lake and what season it was when they were caught. Chinook Salmon on the other hand either consumed Alewife or when they had trouble finding Alewife they had empty stomachs. Interestingly, Rainbow Trout stomachs contained large quantities of terrestrial invertebrates, which is likely a reflection of being caught by anglers, rather than what they derive most of their energy from. These results indicate the Chinook Salmon relies on Alewife for prey whereas other species of salmon are able to take advantage of different resources, when available.
University of Wisconsin-Milwaukee, Purdue University, The College At Brockport – SUNY, Michigan Department of Natural Resources, Illinois Department of Natural Resources, US Fish and Wildlife Service, US Geological Survey.
Undergraduates / Graduates
- Nathan Barker, SUNY
- Michele Edwards SUNY
- Chris Maier SUNY. PhD: Austin Happel, University of Illinois at Urbana-Champaign.
Illinois Natural History Survey