Date of Graduation

2016

Document Type

Thesis

Degree Type

MS

College

Davis College of Agriculture, Natural Resources and Design

Department

Animal and Nutritional Sciences

Committee Chair

Kyle J Hartman

Committee Co-Chair

Yong-Lak Park

Committee Member

Stuart A Welsh

Abstract

This thesis aims to investigate the foraging behavior of Brook Trout (Salvelinus fontinalis), specially focusing on prey preference. Brook Trout are mainly restricted to head-water streams in Appalachia, which is a portion of their native range. These environments generally have low autochthonous materials. Therefore, resident aquatic organisms rely heavily on terrestrial inputs, i.e. leaf litter and terrestrial invertebrates (TI's), to subsidize individual energy requirements at critical times of the year. There is mixed evidence demonstrating stream dwelling trout show either a feeding preference towards aquatic invertebrates (AI's) or towards TI's. Chapter one is an in depth literature review of headwater stream systems, and the external and internal factors contributing to prey selection by riverine trout species. Chapter two encompasses our observational field study of four select streams contained in the Monongahela National Forest, West Virginia. Since these streams are contained in the national forest, they are relatively unimpaired and allowed for adequate numbers of Brook Trout to be collected. These samples were compared to kicknet samples representing AI's available in the environment. Results show a clear trend, in that, Brook Trout forage on AI's overall, in relatively equal proportions to prey availability in spring and summer. Individual taxa preferences did change as well as size selection across seasons, potentially indicating in the springtime they are foraging more on the benthos and from the drift as well as being more size selective. Furthermore, individual variability exists in which preferences and specialization was shown for either AI's or TI's in each season. These results suggest Brook Trout are operating under the Optimal Foraging Theory. Brook Trout have the propensity to change their foraging behavior in a short amount of time which will allow them to combat future anthropogenic changes if management efforts are focused on both the surrounding terrestrial landscape (i.e. riparian corridor) as well as the in stream habitat restoration.

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