Date of Award

Summer 8-17-2020

Semester of Degree

August

Document Type

Open Access Thesis

Degree Name

M.S. in Environmental and Forest Biology

Department

Environmental and Forest Biology

Major Professor

Neil Ringler

Steering Committee Member

Stephen Stehman

Steering Committee Member

Danielle Hurley

Steering Committee Member

Edward Glaza

Abstract

The use of artificial structure as a tool to enhance habitat availability for fish is commonly used in both marine and freshwater systems. Two hypotheses are used to explain how artificial structure affects biota. While the attraction hypothesis states that fish are simply attracted to structure, the production hypothesis suggests that structure also leads to an increase in overall fish abundance by providing an increased availability for foraging, protection from predators, and suitable nesting habitat. Onondaga Lake in Syracuse, New York, is an EPA Superfund Site that has experienced more than a century of degradation. Restoration efforts of this system have included extensive dredging and capping with sand and activated carbon, followed by the establishment of an upper habitat layer consisting of hundreds of artificial structures, including log cribs, downed trees, cobble bars, and concrete reef balls. Reef balls are a structure commonly used in marine environments rather than freshwater. In 2019, visual surveys at these four structure types found that fish are more attracted to sites with structure than sites without, and that fish attraction was highest at woody structures. Numerous discrete behavioral observations of fish were observed at these structures, including schooling, territoriality, and feeding on structure surfaces, indicating that these structures are providing both an increase in forage habitat and protection from predators. Quantification of increased fish abundance in response to the implementation of artificial structure was outside the scope of this study. However, annual trends in centrarchid nest distribution suggest that modification of the substrate following capping coupled with the introduction of artificial structures has led to a broader distribution of centrarchid nests in the littoral zone of the lake by providing diversified substrate and habitat, offering further support for the production hypothesis in freshwater systems.

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