A Lota lota consumption: Trophic dynamics of nonnative Burbot in a valuable sport fishery

Transactions of the American Fisheries Society
By: , and 

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Abstract

Unintentional and illegal introductions of species disrupt food webs and threaten the success of managed sport fisheries. Although many populations of Burbot Lota lota are declining in the species’ native range, a nonnative population recently expanded into Flaming Gorge Reservoir (FGR), Wyoming–Utah, and threatens to disrupt predator–prey interactions within this popular sport fishery. To determine potential impacts on sport fishes, especially trophy Lake Trout Salvelinus namaycush, we assessed the relative abundance of Burbot and quantified the potential trophic or food web impacts of this population by using diet, stable isotope, and bioenergetic analyses. We did not detect a significant potential for food resource competition between Burbot and Lake Trout (Schoener’s overlap index = 0.13), but overall consumption by Burbot likely affects other sport fishes, as indicated by our analyses of trophic niche space. Diet analyses suggested that crayfish were important diet items across time (89.3% of prey by weight in autumn; 49.4% in winter) and across Burbot size-classes (small: 77.5% of prey by weight; medium: 76.6%; large: 39.7%). However, overall consumption by Burbot increases as water temperatures cool, and fish consumption by Burbot in FGR was observed to increase during winter. Specifically, large Burbot consumed more salmonids, and we estimated (bioenergetically) that up to 70% of growth occurred in late autumn and winter. Further, our population-wide consumption estimates indicated that Burbot could consume up to double the biomass of Rainbow Trout Oncorhynchus mykiss stocked annually (>1.3 × 105 kg; >1 million individuals) into FGR. Overall, we provide some of the first information regarding Burbot trophic interactions outside of the species’ native range; these findings can help to inform the management of sport fisheries if Burbot range expansion occurs elsewhere.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title A Lota lota consumption: Trophic dynamics of nonnative Burbot in a valuable sport fishery
Series title Transactions of the American Fisheries Society
DOI 10.1080/00028487.2016.1227372
Volume 145
Issue 6
Year Published 2016
Language English
Publisher Taylor & Francis
Contributing office(s) Coop Res Unit Seattle
Description 13 p.
First page 1386
Last page 1398
Country United States
State Utah, Wyoming
Other Geospatial Flaming Gorge Reservoir