Larval Coregonus spp. diets and zooplankton community patterns in the Apostle Islands, Lake Superior

Journal of Great Lakes Research
By: , and 

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Abstract

With the exception of lake whitefish (Coregonus clupeaformis), relatively little is known about the early life history of larval coregonines in the Laurentian Great Lakes. For example, our knowledge of the feeding ecology of larval coregonines (excluding lake whitefish) is based on only 900 stomachs reported in the literature. Here, we describe the diets and demographics of larval coregonines from ice-out to late July, and the contemporaneous zooplankton community, in the Apostle Islands region of Lake Superior in 2018. Exogenous feeding was evident among the smallest larvae (down to 6 mm). Percent of larvae with food in their stomachs increased and yolk reserves decreased as larvae grew from 10 to 13 mm. A majority of the diet (58%) was copepod nauplii, with generally positive selection for adult copepods and Holopedium. The patterns in exogenous feeding and yolk sac absorption were similar to observations in Lake Superior in the 1970s. Diets were also generally similar, although LimnocalanusHolopedium, and zooplankton eggs were more prevalent in 2018 than the 1970s. Demographic data suggested at least two distinct cohorts and/or coregonine species in 2018. Post-hoc genetic testing of larvae in a parallel study suggested our samples comprised a mix of predominantly cisco (C. artedi), kiyi (C. kiyi), and bloater (C. hoyi). Early life history studies, when coupled with emerging genetic techniques that can identify larval coregonines to species, will provide a powerful combination to better understand population dynamics of coregonines at a time of ongoing restoration and rehabilitation efforts throughout the Great Lakes.

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Publication type Article
Publication Subtype Journal Article
Title Larval Coregonus spp. diets and zooplankton community patterns in the Apostle Islands, Lake Superior
Series title Journal of Great Lakes Research
DOI 10.1016/j.jglr.2020.07.001
Volume 46
Issue 5
Year Published 2021
Language English
Publisher Elsevier
Contributing office(s) Great Lakes Science Center
Description 11 p.
First page 1391
Last page 1401
Country United States
Other Geospatial Apostle Islands, Lake Superior
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