Double-crested cormorant studies at Little Galloo Island, Lake Ontario in 2008: Diet composition, fish consumption and the efficacy of management activities in reducing fish predation

NYSDEC Lake Ontario Annual Report 2008-14
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Abstract

For almost two decades Little Galloo Island (LGI)has supported the largest colony of double-crested cormorants (Phalacrocorax auritus) in the eastern basin of Lake Ontario. Cormorant nest counts on the island since the early 1990's have averaged about 5,000 per year reaching a high of 8,400 in 1996. Johnson et al. (2008) estimate that cormorants from LGI alone have consumed 400 million fish since 1992. The proliferation of cormorants in the eastern basin of Lake Ontario has coincided with declines in two important recreational fish species, smallmouth bass and yellow perch. Lantry et al. (2002) and Burnett et al. (2002) provide convincing evidence linking cormorant population increases to declining eastern basin smallmouth bass and yellow perch stocks. Decline of these fish stocks is evident only in the eastern basin, suggesting a localized problem which is consistent with the halo effect where large piscivorous waterbird colonies may deplete local fish stocks (Birt et al. 1987).

The year 2008 marked the seventeenth consecutive year of study of the food habits and fish consumption of LGI cormorants, and represented the tenth consecutive year evaluating the efficacy of management activities to control the reproductive success of cormorants nesting at LGI. The program consists mainly of spraying cormorant eggs with oil as well as the culling of adult and immature birds.This paper reports the findings of work carried outin 2008 at LGI.

Study Area

Publication type Report
Publication Subtype State or Local Government Series
Title Double-crested cormorant studies at Little Galloo Island, Lake Ontario in 2008: Diet composition, fish consumption and the efficacy of management activities in reducing fish predation
Series title NYSDEC Lake Ontario Annual Report
Series number 2008
Chapter 14
Year Published 2008
Language English
Publisher New York State Department of Environmental Conservation
Publisher location Albany, NY
Contributing office(s) Great Lakes Science Center
Description 11 p.
Larger Work Type Report
Larger Work Subtype State or Local Government Series
Larger Work Title 2008 NYSDEC Lake Ontario Annual Report
First page 14-1
Last page 14-11
Country Canada, United States
Other Geospatial Lake Ontario
Online Only (Y/N) N
Additional Online Files (Y/N) N
Google Analytic Metrics Metrics page
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