Date of Award
Summer 7-16-2025
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Biology
First Advisor
Melissa Wuellner
Committee Members
Keith Koupal and Mark Pegg
Abstract
Artificial lentic systems, such as borrow pits, often lack structural complexity due to construction practices and steep bathymetry, limiting features like vegetation and woody debris essential for fish communities. To address this, artificial structures made of materials such as polyvinyl chloride are increasingly used by state and federal agencies to supplement habitat. However, little information is known about the impact these structures have on fish communities. Thus, the objectives of this study were to examine the influence of Georgia cubes in borrow pit impoundments on overwinter survival of sub-stock and ≥ stock Bluegill (Lepomis macrochirus) and Largemouth Bass (Micropterus nigricans), and to quantify and compare the seasonal spatial finprint (spatial extent of fish aggregation around structures) of Georgia cube complexes placed in two Nebraska borrow pits. For the first objective, modified Georgia cubes wrapped in two sizes of wire mesh were installed in three treatment lakes. Electrofishing surveys conducted in fall and spring were used to estimate overwinter survival based on changes in catch-per-unit-effort compared to three control lakes over two years. Survival varied, particularly for sub-stock Bluegill, which did not consistently benefit from added structures. For the second objective, three standard Georgia cube complexes were deployed in two borrow pits and electrofished monthly at 0, 4.5, and 9 m to estimate finprints over two years (17 months). Finprints varied by lake, season, and year, with larger finprints typically observed in fall and winter. Catches were significantly higher in fall than summer (p = 0.01), and higher directly on the structure than at either distance away (p < 0.01), with no difference between 4.5 and 9 m (p = 0.99). The maximum seasonal finprint observed was 16.5 m, suggesting cubes be spaced at least 33 m apart in similar waterbodies. Overall, the results offer a framework for future habitat projects.
Recommended Citation
Dietrich, Logan, "IMPACTS OF ARTIFICIAL HABITAT STRUCTURES ON OVERWINTER FISH SURVIVAL AND FISH PRESENCE IN SOUTH-CENTRAL NEBRASKA" (2025). Biology Theses, Dissertations, and Student Creative Activity. 25.
https://openspaces.unk.edu/bio-etd/25