Alewife planktivory controls the abundance of two invasive predatory cladocerans in Lake Michigan

1. We sampled along a nearshore transect (10-m bathymetric contour) in Lake Michigan to determine diet, 24-h feeding periodicity, daily ration and food requirements of an invasive fish, the alewife, Alosa pseudoharengus, relative to zooplankton abundance and production. Our objective was to determin...

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Bibliographic Details
Published in:Freshwater biology 2007-03, Vol.52 (3), p.561-573
Main Authors: POTHOVEN, STEVEN A, VANDERPLOEG, HENRY A, CAVALETTO, JOANN F, KRUEGER, DAMON M, MASON, DORAN M, BRANDT, STEPHEN B
Format: Article
Language:English
Subjects:
alewife
Alosa pseudoharengus
Bosminidae
Bythotrephes
Bythotrephes longimanus
Cercopagis
Cercopagis pengoi
Chironomidae
Chydoridae
Cladocera
daily ration
Freshwater
Leptodora
planktivory
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Summary:1. We sampled along a nearshore transect (10-m bathymetric contour) in Lake Michigan to determine diet, 24-h feeding periodicity, daily ration and food requirements of an invasive fish, the alewife, Alosa pseudoharengus, relative to zooplankton abundance and production. Our objective was to determine whether the alewife controls the abundance of two invasive, predatory cladocerans, Bythotrephes longimanus and Cercopagis pengoi. 2. Bosminidae was the most abundant prey taxon and Chydoridae, Leptodora, Chironomidae and Bythotrephes were the least abundant. Neither Bythotrephes nor Cercopagis were important prey for small alewives ( 3. Food weight in stomachs was highest early in the night for small alewives and lowest at night for large alewives. Chironomidae and large Chydoridae were the preferred prey of small alewives. Bythotrephes and large Chydoridae were the preferred prey for large alewives. 4. Food requirements of alewife were much less than production for most prey taxa, although the consumption of Bythotrephes greatly exceeded production on both dates. Alewives consumed only 3% of Cercopagis production. High selectivity and food requirements of alewife for Bythotrephes, and low selectivity and food requirements for Cercopagis, probably explain the difference in abundance between these two invasive cladocerans at our nearshore site in Lake Michigan.
ISSN:0046-5070
1365-2427
DOI:10.1111/j.1365-2427.2007.01728.x