Diet shift of double-crested cormorants in eastern Lake Ontario associated with the expansion of the invasive round goby

Journal of Great Lakes Research
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Abstract

The proliferation of the invasive round goby (Apollonia melanostoma) in the Great Lakes has caused shifts in the trophic ecology in some areas. We examined the diet of double-crested cormorants (Phalacrocorax auritas) prior to, and immediately after, round goby population expansion at two colonies, Pigeon and Snake Islands, in eastern Lake Ontario from 1999 to 2007. Cormorant diet was determined from the examination of 10,167 pellets collected over the nine-year period. By the second year round gobies were found in the diet (2002 at Snake Island and 2003 at Pigeon Island) they were the main species consumed by cormorants at each colony. The dominance of round goby in cormorant diets had a significant effect on both daily fish consumption and seasonal trends in fish consumption compared to the pre-goby years. Seasonal differences that were observed during the pre-goby years were lost once gobies became the main diet component of cormorants. The rapid switch to a benthic prey such as round goby, from a largely limnetic fish diet demonstrates the adaptive foraging ability of cormorants. Round goby may act as a buffer for yellow perch and smallmouth bass, two sport fish impacted by cormorant predation in eastern Lake Ontario.

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Publication type Article
Publication Subtype Journal Article
Title Diet shift of double-crested cormorants in eastern Lake Ontario associated with the expansion of the invasive round goby
Series title Journal of Great Lakes Research
DOI 10.1016/j.jglr.2010.02.013
Volume 36
Issue 2
Year Published 2010
Language English
Publisher International Association for Great Lakes Research
Publisher location Ann Arbor, MI
Contributing office(s) Great Lakes Science Center
Description 6 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Journal of Great Lakes Research
First page 242
Last page 247
Time Range Start 1999-01-01
Time Range End 2007-12-31
Country United States
Other Geospatial Lake Ontario
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