Declines and shifts in morphological diversity of ciscoes (Coregonus spp.) in lakes Huron and Michigan, 1917–2019

Canadian Journal of Fisheries and Aquatic Sciences
By: , and 

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Abstract

Ciscoes (Coregonus spp.) were historically abundant and ecologically important in Laurentian Great Lakes ecosystems. Despite well-documented declines in their abundance and taxonomic diversity, declines in morphological diversity remain understudied. This knowledge gap is especially pertinent for lakes Michigan and Huron, which have each lost six of eight historical species. Improved understanding of historical and contemporary morphological diversity of Great Lakes ciscoes can inform ongoing restoration efforts and further elucidate the factors that contributed to declines. Our goal was to characterize shifts in morphological diversity of ciscoes in lakes Michigan and Huron over a century (1917–2019). We analyzed size-corrected morphometric and meristic measurements from three periods: Early (1917–1923), Middle (1950–1972), and Contemporary (2015–2019). We then identified morphologically distinct clusters while remaining agnostic to species identifications. We found that morphological diversity and the number of distinct clusters declined over time. We then leveraged species identifications to highlight key species losses and examine morphological shifts among extant species. Our findings provide insights into the historical and contemporary morphological diversity of ciscoes and will inform restoration efforts.

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Publication type Article
Publication Subtype Journal Article
Title Declines and shifts in morphological diversity of ciscoes (Coregonus spp.) in lakes Huron and Michigan, 1917–2019
Series title Canadian Journal of Fisheries and Aquatic Sciences
DOI 10.1139/cjfas-2023-0357
Volume 81
Issue 9
Year Published 2024
Language English
Publisher Canadian Science Publishing
Contributing office(s) Great Lakes Science Center
Description 13 p.
First page 1292
Last page 1304
Country United States
Other Geospatial Lake Huron, Lake Michigan
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