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The Impact of Double-Crested Cormorants on the Mississippi Delta Catfish Industry: A Bioenergetics Model

James F. Glahn and Kristin E. Brugger
Colonial Waterbirds
Vol. 18, Special Publication 1: The Double-Crested Cormorant: Biology, Conservation and Management (1995), pp. 168-175
Published by: Waterbird Society
DOI: 10.2307/1521537
Stable URL: http://www.jstor.org/stable/1521537
Page Count: 8
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Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
The Impact of Double-Crested Cormorants on the Mississippi Delta Catfish Industry: A Bioenergetics Model
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Abstract

A bioenergetics model was constructed and evaluated for estimating Double-crested Cormorant (Phalacrocorax auritus) energy expenditures, food demand and impact on the Channel Catfish (Ictalurus punctatus) industry in the Delta region of Mississippi. Large body mass (mean = 2.27 kg) and higher basal metabolism (115% to 128% of predicted) resulted in an average predicted food demand of 504 g/bird/day (range: 449 to 551) from November to March or 22% of body mass. Factoring in population sizes and proportional intake of catfish, Double-crested Cormorants may have eaten up to 20 million catfish per winter in 1989-90 and 1990-91 or approximately 4% of the estimated standing crop at a replacement cost of $2 million (US$) annually. More than 50% of catfish losses were projected to occur in February and March; negligible losses occurred in November.

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