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Evaluating change in lake whitefish feeding habits

Great Lakes food webs have changed dramatically since the   establishment of dreissenid mussels, highlighted by large declines   in Diporeia abundance. Recent work has linked lake whitefish growth   declines in South Bay, Lake Huron to change in the benthic   invertebrate community, where whitefish were distributed more   nearshore and diets were dominated by energy-poor nearshore prey   following dreissenid invasion. In contrast, anecdotal reports from   commercial fishermen suggest that whitefish in Lake Huron?s main   basin have moved deeper. Despite this, hypotheses regarding temporal   changes in whitefish depth distributions elsewhere in the Great   Lakes have not yet been tested empirically. We will provide a more   comprehensive spatial and temporal understanding of the extent to   which whitefish feeding and depth distribution have changed in other   parts of the Great Lakes. We will also provide further empirical   evaluation of the nearshore phosphorous shunt model (Hecky et al.   2  4), which posits that dreissenids have contributed to a shift in   productivity from offshore to nearshore areas.  Our research   objectives are to: (1) Test the hypothesis that declines in lake   whitefish growth rate have occurred in regions where dreissenids   have become established; (2) Test the hypothesis that declines in   lake whitefish growth rate are related to changes in diet (implied   through isotopes) coincident with the establishment of dreissenids;   (3) Test the degree to which temporal changes in lake whitefish diet   (implied through isotopes) are influenced by changes in lake   whitefish vertical distribution. To complete these objectives we   will gather archived scale samples from various netting programs to   measure carbon (C) and nitrogen (N) isotopes and analyze data on   growth and depth distribution for populations of lake whitefish   around the Great Lakes.

Status
In progress
Type
Project
Start Date
End Date
Scope of Study
Field Investigation
Laboratory Investigation
Scale of Phenomena
Community
Impact of Pollutants
Exotic Species
Processes
Natural Ecological Processes
Resource Management
Fisheries
Biology And Life History
Population Dynamics
Control And Mitigation
Biological Interactions (Predator/Prey)
Ecosystem Effects
Food Web Structure
Annex Numbers
Research & Development
Annex 17
Impact of water quality and AIS on fish and wildlife populations and habitats
General
Aquatic Nuisance Species
Annex
  • Annex Numbers
    Annex Numbers
    Research & Development
  • Annex 17
    Annex 17
    Impact of water quality and AIS on fish and wildlife populations and habitats

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