Date of Award

Summer 8-2011

Degree Type

Masters Thesis

Degree Name

Master of Science (MS)

Department

Biological Sciences

Committee Chair

Dr. Jake Schaefer

Committee Chair Department

Biological Sciences

Committee Member 2

Dr. Michael Davis

Committee Member 2 Department

Biological Sciences

Committee Member 3

Dr. Carl P. Qualls

Committee Member 3 Department

Biological Sciences

Abstract

Patterns of piscine prey selection and habitat usage of Esox americanus were assessed through a series of field and experimental studies. Although few detailed studies exist on the foraging behavior and habitat usage of E. americanus, throughout its range it may be an important trophic component in maintaining fish assemblage structure in many lower order streams. Across 17 sampled streams, the presence of E. americanus among reaches within streams was found to be strongly correlated with increasing levels of habitat complexity. Reaches occupied by E. americanus featured increased amounts of in-stream physical structure, increased variability in stream width and depth, decreased water temperatures and dissolved oxygen content. Because of its lie-in-wait, ambush attack strategy, habitat complexity was likely a facilitator of prey selection. In a series of outdoor mesocosms experiments featuring alternative forms of structural cover types, four prey species were offered and E. americanus exhibited differing intensities of selectivity among prey types. Field selectivity was assessed from 18 sites by clustering species of potential prey assemblages into a series of functional groups using a suite of traits representing species’ habitat affinities and morphological characteristics. A pattern of non-random feeding in both field and experimental mesocosm studies indicate that E. americanus was selecting prey of a similar body type, choosing soft-rayed, fusiform prey over alternative morphologies.

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