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Cormorant Pellet Contents

Abstract: Breeding populations of double-crested cormorants in Lake Ontario have
undergone dramatic changes since the first documented nesting on
Scotch Bonnet Island in 1938. Scientists believe that the declines
observed prior to 1974 were due largely to rising burdens of
chlorinated hydrocarbons (especially the insecticide DDT and its
metabolites) in the birds and their negative effects on reproductive
output. By the mid 1970s, contaminant levels in cormorant eggs were
reported to be falling while reproductive success began to
increase. The expanded breeding population of double-crested
cormorants in Lake Ontario has led to an inevitable conflict between
the sportfishing industry and bird enthusiasts as well as the resource
agencies charged with protecting wildlife and assessing fish stocks.
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Geographic Coverage
Spatial coordinates   
  N: 44.0   S: 44.0   E: -76.0   W: -76.0

Data Set Citation
Dataset Originator/Creator: Robert M. Ross, and James H. Johnson
Dataset Title: Cormorant Pellet Contents
Dataset Release Date: 1997-05-08
Dataset Release Place: Wellsboro, PA
Dataset Publisher: Leetown Science Center (now BRD, USGS)
Temporal Coverage
Start Date: 1992-04-01
Stop Date: 1994-07-01
Location Keywords
Access Constraints none
Use Constraints none
Data Set Progress
Originating Center
Email: rossr at
Ross, Robert M. and James H. Johnson. Seasonal and Annual Changes in
the Diet of Double-crested Cormorants: Implications for Lake Ontario's
Fishery. Great Lakes Research Review. Vol. 2, No. 1, July 1995.
Extended Metadata Properties
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Creation and Review Dates
Last DIF Revision Date: 2017-08-23