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United States Department of Agriculture

Agricultural Research Service

Title: IS IT NECESSARY TO IDENTIFY DIET ITEMS FROM HARD PARTS TO ACCURATELY CHARACTERIZE CORMORANT DIETS?

Authors
item Fenech, Amy - UAPB
item Lochmann, Steve - UAPB
item Radomski, Andrew

Submitted to: Southern Division American Fisheries Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: December 11, 2002
Publication Date: February 7, 2003
Citation: FENECH, A.S., LOCHMANN, S.E., RADOMSKI, A.A. IS IT NECESSARY TO IDENTIFY DIET ITEMS FROM HARD PARTS TO ACCURATELY CHARACTERIZE CORMORANT DIETS?. SOUTHERN DIVISION AMERICAN FISHERIES SOCIETY ANNUAL MEETING. 2003. p.6.

Technical Abstract: Diets of double-crested cormorants Phalocrocorax auritus have been the subject of several studies. Description of the diet from regurgitated pellets and fecal material rely heavily on diagnostic hard parts. Diet characterization from stomach contents of collected birds typically relies on intact prey remains. Analyses of diet based on only one method may bias characterizations. The purpose of this study was to describe the diet of wintering cormorants from intact prey items and diagnostic hard parts and compare this estimate with the diet described using only intact prey items. Approximately 1371 prey items were identified from intact remains or hard parts. In fall, based on intact remains alone, gizzard shad were the most numerous and frequently occuring prey taxa, and had the highest relative importance. In the fall, based on hard parts and intact remains, cyprinids were the most numerous taxa and had the highest relative importance. Gender-based diet differences were not affected by choice of method. Length fequency distributions did not differ. We have determined it is sufficient to use only intact remains for diet characterization of cormorants unless specific seasonal information is required.

Last Modified: 8/27/2014
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