Date of Award

Fall 2024

Project Type

Thesis

Program or Major

Biological Sciences

Degree Name

Master of Science

First Advisor

Michael Chambers

Second Advisor

Christopher Neefus

Third Advisor

Michael Coogan

Abstract

Growing shrimp with extractive species is gaining momentum to reduce effluent waste in aquaculture systems. Preliminary experiments were conducted at the University of New Hampshire’s Spaulding laboratory to calculate total ammonia nitrogen uptake rates by Gracilaria vermiculophylla and output rates by whiteleg shrimp, Litopenaeus vannamei. Based on these results, oysters and red algae were incorporated into a shrimp recirculating aquaculture system at University of New Hampshire’s Coastal Marine Laboratory to determine their effectiveness in reducing dissolved nitrogen. This is a critical step in mitigating negative impacts to ecosystems surrounding shrimp aquaculture operations, while producing valuable biproducts. An aquatic habitat (AHAB) system was used, which consisted of 36 individual 9L tanks vertically stacked into 9 columns and 4 rows, each column making up an isolated system. A 4-week trial was conducted comparing three treatment groups: 1) shrimp grown with oysters and red algae, 2) shrimp grown with only red algae, and 3) shrimp grown with red algae as well as aeration to re-suspend waste particles. No additional biofilters or mechanical filters were used. Oysters were found to have a significant impact on maintaining low nitrogen levels in the system over time compared to treatments with no oysters (p ≤ 0.032). A second one-week trial was conducted to compare systems with different ratios of shrimp to seaweed biomass. Shrimp were grown with the same ratio as the first trial; a shrimp:seaweed ratio of 1:2, and an increased ratio of 1:3 and 1:4. Water samples for both trials were collected once a day before feeding, and once a week before feeding and at regular intervals up to five hours after feeding. Biomass data was also collected once a week throughout the experiment. Results suggest a higher growth rate for G. vermiculophylla in a ratio of 1:3 shrimp:seaweed, as well as a significantly higher combined nitrite + nitrate concentration maintained in the 1:3 ratio treatment compared to the other two treatments.

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