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Stable isotope evaluation of population- and individual-level diet variability in a large, oligotrophic lake with non-native lake trout

Ecology of Freshwater Fish

By:
, , and
https://doi.org/10.1111/eff.12273

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Abstract

Non-native piscivores can alter food web dynamics; therefore, evaluating interspecific relationships is vital for conservation and management of ecosystems with introduced fishes. Priest Lake, Idaho, supports a number of introduced species, including lake troutSalvelinus namaycush, brook trout S. fontinalis and opossum shrimp Mysis diluviana. In this study, we used stable isotopes (δ13C and δ15N) to describe the food web structure of Priest Lake and to test hypotheses about apparent patterns in lake trout growth. We found that isotopic niches of species using pelagic-origin carbon did not overlap with those using more littoral-origin carbon. Species using more littoral-origin carbon, such as brook trout and westslope cutthroat trout Oncorhynchus clarki lewisi, exhibited a high degree of isotopic niche overlap and high intrapopulation variability in resource use. Although we hypothesised that lake trout would experience an ontogenetic diet shift, no such patterns were apparent in isotopic signatures. Lake trout growth rates were not associated with patterns in δ15N, indicating that variation in adult body composition may not be related to adult diet. Understanding trophic relationships at both the individual and species levels provides a more complete understanding of food webs altered by non-native species.

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Additional publication details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Stable isotope evaluation of population- and individual-level diet variability in a large, oligotrophic lake with non-native lake trout
Series title:
Ecology of Freshwater Fish
DOI:
10.1111/eff.12273
Volume:
26
Issue:
2
Year Published:
2016
Language:
English
Publisher:
John Wiley & Sons
Contributing office(s):
Coop Res Unit Seattle
Description:
9 p.
First page:
271
Last page:
279
Country:
United States
State:
Idaho
Other Geospatial:
Lake Priest
Online Only (Y/N):
N
Additional Online Files (Y/N):
N