Lake Michigan offshore ecosystem structure and food web changes from 1987 to 2008

Canadian Journal of Fisheries and Aquatic Sciences
By: , and 

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Abstract

Ecosystems undergo dynamic changes owing to species invasions, fisheries management decisions, landscape modifications, and nutrient inputs. At Lake Michigan, new invaders (e.g., dreissenid mussels (Dreissena spp.), spiny water flea (Bythotrephes longimanus), round goby (Neogobius melanostomus)) have proliferated and altered energy transfer pathways, while nutrient concentrations and stocking rates to support fisheries have changed. We developed an ecosystem model to describe food web structure in 1987 and ran simulations through 2008 to evaluate changes in biomass of functional groups, predator consumption, and effects of recently invading species. Keystone functional groups from 1987 were identified as Mysis, burbot (Lota lota), phytoplankton, alewife (Alosa pseudoharengus), nonpredatory cladocerans, and Chinook salmon (Oncorhynchus tshawytscha). Simulations predicted biomass reductions across all trophic levels and predicted biomasses fit observed trends for most functional groups. The effects of invasive species (e.g., dreissenid grazing) increased across simulation years, but were difficult to disentangle from other changes (e.g., declining offshore nutrient concentrations). In total, our model effectively represented recent changes to the Lake Michigan ecosystem and provides an ecosystem-based tool for exploring future resource management scenarios.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Lake Michigan offshore ecosystem structure and food web changes from 1987 to 2008
Series title Canadian Journal of Fisheries and Aquatic Sciences
Volume 71
Issue 7
Year Published 2014
Language English
Publisher NRC Research Press
Publisher location Ottawa, Canada
Contributing office(s) Great Lakes Science Center
Description 15 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Canadian Journal of Fisheries and Aquatic Sciences
First page 1072
Last page 7086
Country United States
Other Geospatial Lake Michigan
Online Only (Y/N) N
Additional Online Files (Y/N) N