Among-individual diet variation within a lake trout ecotype: lack of stability of niche use

Chavarie, L., Howland, K.L., Harris, L.N., Gallagher, C.P., Hansen, M.J., Tonn, W.M., Muir, A.M. and Krueger, C.C. (2021) Among-individual diet variation within a lake trout ecotype: lack of stability of niche use. Ecology and Evolution, 11(3), pp. 1457-1475. (doi: 10.1002/ece3.7158) (PMID:33598144) (PMCID:PMC7863394)

Abstract

In a polyphenic species, differences in resource use are expected among ecotypes, and homogeneity in resource use is expected within an ecotype. Yet, using a broad resource spectrum has been identified as a strategy for fishes living in unproductive northern environments, where food is patchily distributed and ephemeral. We investigated whether specialization of trophic resources by individuals occurred within the generalist piscivore ecotype of lake trout from Great Bear Lake, Canada, reflective of a form of diversity. Four distinct dietary patterns of resource use within this lake trout ecotype were detected from fatty acid composition, with some variation linked to spatial patterns within Great Bear Lake. Feeding habits of different groups within the ecotype were not associated with detectable morphological or genetic differentiation, suggesting that behavioral plasticity caused the trophic differences. A low level of genetic differentiation was detected between exceptionally large‐sized individuals and other piscivore individuals. We demonstrated that individual trophic specialization can occur within an ecotype inhabiting a geologically young system (8,000–10,000 yr BP), a lake that sustains high levels of phenotypic diversity of lake trout overall. The characterization of niche use among individuals, as done in this study, is necessary to understand the role that individual variation can play at the beginning of differentiation processes.

• Item Type: Articles
• Additional Information: Funds are from Fisheries and Oceans Canada (DFO), Northern Development Canada Northwest Territories Cumulative Impacts Monitoring Program grants, Polar Continental Shelf Program, Sahtu Renewable Resource Board, and the Great Lakes Fishery Commission.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Chavarie, Dr Louise

Creator Roles

Chavarie, L.: Conceptualization, Data curation, Formal analysis, Funding acquisition, Investigation, Methodology, Resources, Validation, Visualization, Writing – original draft, Writing – review and editing

• Authors: Chavarie, L., Howland, K.L., Harris, L.N., Gallagher, C.P., Hansen, M.J., Tonn, W.M., Muir, A.M., and Krueger, C.C.
• College/School: College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
• Journal Name: Ecology and Evolution
• Publisher: Wiley
• ISSN: 2045-7758
• ISSN (Online): 2045-7758
• Published Online: 19 January 2021
• Copyright Holders: Copyright © 2021 The Authors
• First Published: First published in Ecology and Evolution 11(3):1457-1475
• Publisher Policy: Reproduced under a Creative Commons License