From yellow perch to round goby: A review of double-crested cormorant diet and fish consumption at three St. Lawrence River colonies, 1999–2013

Journal of Great Lakes Research
New York State Department of Environmental Conservation; Ontario Ministry of Natural Resources
By: , and 

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Abstract

The number of double-crested cormorants (Phalacrocorax auritus) in the upper St. Lawrence River has increased markedly since the early 1990s. In 1999, a binational study was initiated to examine the annual diet composition and fish consumption of cormorants at colonies in the upper river. Since 1999, 14,032 cormorant pellets, collected from May through September each year, have been examined from St. Lawrence River colonies to estimate fish consumption and determine temporal and spatial variation in diet. Seasonal variation in diet composition within a colony was low. Prior to 2006 yellow perch was the primary fish consumed by cormorants in the upper St. Lawrence River. Round goby were first observed in cormorant diets in 2003 and by 2006 were the main fish consumed at two of the three colonies. The time interval it took from the first appearance of round goby in the diet at a colony to when goby were the dominant prey species varied by island, ranging from two to five years. Daily fish consumption at each cormorant colony increased significantly from the pre-round goby to post-round goby period. The mean annual biomass of yellow perch consumed decreased significantly during the post-round goby period at the three colonies. Reduced consumption of yellow perch by cormorants may alleviate suspected localized impacts on perch near some of the larger river colonies.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title From yellow perch to round goby: A review of double-crested cormorant diet and fish consumption at three St. Lawrence River colonies, 1999–2013
Series title Journal of Great Lakes Research
DOI 10.1016/j.jglr.2014.12.011
Volume 41
Issue 1
Year Published 2015
Language English
Publisher International Association for Great Lakes Research
Publisher location Toronto
Contributing office(s) Great Lakes Science Center
Description 7 p.
First page 259
Last page 265
Country Canada, United States
State New York, Ontario
Other Geospatial Griswold Island, McNair Island, Strachan Island
Online Only (Y/N) N
Additional Online Files (Y/N) N