Date of Award

Spring 5-21-2025

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Biology

First Advisor

Dr. Melissa Wuellner

Committee Members

Dr. Melissa Wuellner

Dr. Paul Twigg

Dr. Matthew Bice

Keywords

Aquaponics, Sustainability, Brewer's Spent Grain, Reclaimed Materials

Abstract

Future food production requires sustainable approaches that used both land and water resources efficiently, while remaining economically viable. One approach is aquaponics, the practice which combines hydroponics and aquaculture, as a sustainable food producing system. Aquaponic systems are unique, as the system can be designed to reuse and repurpose locally sourced materials and resources to meet individual needs. However, productivity of these systems can be inefficient or inconsistent, impacting the viability of aquaponics. The first objective of my study was to compare how system design between a do-it yourself reclaimed-materials aquaponic system and a prefabricated aquaponic setup affects water quality and fish and plant growth over time. Therefore, two experiments, a high stocking density with an equal number of plants, and a low stocking density with equal planting densities were designed to investigate system performance. Throughout each experiment, water quality remained within the recommended range for aquaponics; however, both fish and plant productivity changed between experiments, potentially due to differences in water quality, fish stocking densities, and plant densities between systems and experiments. The second objective was to determine if a partial substitution aquafeed using 50% brewer’s spent grain will perform similarly to a 100% commercially species specific aquafeed in terms of water quality and fish and plant growth in an aquaponic system. Pure-strain blue tilapia fry were randomly assigned to either the commercial feed or home-blend feed tan k growing sweet basil seedlings, with weekly water quality metrics measured. Water quality did change over time but the rate of change was not significantly different; however, both fish growth and basil yield were significantly different. My results suggest that a partial substitution of brewer’s spent grain does not impact water quality positively or negatively, but my contribute to lower fish and plant growth rates when compared to a commercial aquafeed.

Included in

Biology Commons

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