Winter feeding, growth and condition of brown trout Salmo trutta in a groundwater-dominated stream

Journal of Freshwater Ecology
By: , and 

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Abstract

Winter can be a stressful period for stream-dwelling salmonid populations, often resulting in reduced growth and survival. Stream water temperatures have been identified as a primary mechanism driving reductions in fitness during winter. However, groundwater inputs can moderate water temperature and may reduce winter severity. Additionally, seasonal reductions in prey availability may contribute to decreased growth and survival, although few studies have examined food webs supporting salmonids under winter conditions. This study employed diet, stable isotope, and mark-recapture techniques to examine winter (November through March) feeding, growth, and condition of brown troutSalmo trutta in a groundwater-dominated stream (Badger Creek, Minnesota, USA). Growth was greater for fish ≤ 150 mm (mean = 4.1 mg g−1 day−1) than for those 151–276 mm (mean = 1.0 mg g−1 day−1) during the winter season. Overall condition from early winter to late winter did not vary for fish ≤150 mm (mean relative weight (Wr) = 89.5) and increased for those 151–276 mm (mean Wr = 85.8 early and 89.4 late). Although composition varied both temporally and by individual, brown trout diets were dominated by aquatic invertebrates, primarily Amphipods, Dipterans, and Trichopterans. Stable isotope analysis supported the observations of the dominant prey taxa in stomach contents and indicated the winter food web was supported by a combination of allochthonous inputs and aquatic macrophytes. Brown trout in Badger Creek likely benefited from the thermal regime and increased prey abundance present in this groundwater-dominated stream during winter.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Winter feeding, growth and condition of brown trout Salmo trutta in a groundwater-dominated stream
Series title Journal of Freshwater Ecology
DOI 10.1080/02705060.2013.847868
Volume 29
Issue 2
Year Published 2014
Language English
Publisher Taylor & Francis
Contributing office(s) Coop Res Unit Leetown
Description 14 p.
First page 187
Last page 200
Country United States
State Minnesota
Other Geospatial Badger Creek
Online Only (Y/N) N
Additional Online Files (Y/N) N