Prey Species- and Size-Specific Consumption by Lake Michigan Piscivores

B.S. Leonhardt, T. O. Hook, A. Happel, S.J. Czesny, B. A. Turschak, H. A. Bootsma, J. Rinchard, M.S. Kornis, C.R. Bronte

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Invasive alewives (Alosa psuedoharengus) have been an important diet item for salmonids in Lake Michigan for the last 50 years, especially for Chinook (Oncorhynchus tshawytscha) and Coho salmon (Oncorhynchus kisutch). However, over the past twenty years alewife densities, growth rates, and condition have declined, evidently due to high predation pressure from salmonids and reduced pelagic production and invertebrate prey availability. Concurrently, another invasive forage species, round goby (Neogobius melanostomus), has increased in abundance and become the second most common prey for some salmonids in Lake Michigan. We evaluated of Lake Michigan piscivores by forage species, region and season using stomach content analyses. In addition, we examined size-specific consumption and the potential for individual specialization on specific prey species or sizes of prey. Collectively, alewife and round goby now constitute 99% of prey fish consumed by weight by the five main salmonid species in the lake. The long-term sustainability of this predator-prey system may depend not only on tempering overall predation pressure, but also the partitioning of prey resources by species and size. We will summarize these findings and discuss their implications in the context of sustainable fisheries
Original languageEnglish (US)
Title of host publicationFrom Cities to Farms: Shaping Great Lakes Ecosystems
StatePublished - 2017


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