Diet shifts by planktivorous and benthivorous fishes in northern Lake Michigan in response to ecosystem changes

Journal of Great Lakes Research
By: , and 

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Abstract

In Lake Michigan, diets of planktivorous and benthivorous fishes have varied over the past decades, in part owing to food web changes. To update diet information and compare them to a similar effort in 1994–1995, we analyzed the diets of seven benthivorous and planktivorous fish species collected along two northern Lake Michigan transects that spanned nearshore (18 m), intermediate (46 m), and offshore (91, 110, 128 m) bottom depths during spring, summer, and autumn of 2010. Calanoid copepods (e.g., Limnocalanus macrurus, Leptodiaptomus sicilis, and Senecella calanoides) comprised a majority of the diets in at least one season for all sizes of alewife (Alosa pseudoharengus), bloater (Coregonus hoyi), and rainbow smelt (Osmerus mordax). Similarly, Mysis diluviana was the highest proportion in at least one season for large sizes of alewife, bloater, and rainbow smelt, as well as slimy sculpin (Cottus cognatus) and deepwater sculpin (Myoxocephalus thompsonii). The diets of the remaining two species, ninespine stickleback (Pungitius pungitius) and round goby (Neogobius melanostomus), were dominated by herbivorous cladocerans or dreissenid mussels, respectively. Interspecific diet overlap was minimal at 18 and 46 m. In offshore waters, however, overlap was relatively high, driven by frequent consumption of Mysis. Relative to 1994–1995, 2010 diets revealed increased feeding on calanoid copepods and Mysis, with corresponding declining consumption of Diporeia spp. and herbivorous cladocerans. Relative diet weight was also higher in 1994–1995 than in 2010 for small and large bloater and both sculpin species. We hypothesize that the shifts in diets are reflective of community-level changes in invertebrate prey availability.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Diet shifts by planktivorous and benthivorous fishes in northern Lake Michigan in response to ecosystem changes
Series title Journal of Great Lakes Research
DOI 10.1016/j.jglr.2015.07.011
Volume 41
Issue Suppl. 3
Year Published 2015
Language English
Publisher Elsevier
Contributing office(s) Great Lakes Science Center
Description 11 p.
First page 161
Last page 171
Country United States
State Wisconsin and Michigan
Other Geospatial Sturgeon Bay and Frankfort
Online Only (Y/N) N
Additional Online Files (Y/N) N
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