Date of Award

8-2024

Degree Type

Masters Thesis

Degree Name

Master of Science (MS)

School

Ocean Science and Engineering

Committee Chair

Dr. Leila Hamdan

Committee Chair School

Ocean Science and Engineering

Committee Member 2

Dr. Chet Rakocinski

Committee Member 2 School

Ocean Science and Engineering

Committee Member 3

Dr. Kristina Mojica

Committee Member 3 School

Ocean Science and Engineering

Abstract

Recirculating Aquaculture Systems (RAS) offer control over physicochemical and biological factors impacting aquaculture success. One understudied facet of RASs is the water microbiome. Oyster larval microbiomes are shaped by their aquatic microbiomes. Understanding the dynamics of and the factors shaping RAS microbiome may provide insights to how the microbiome can be a tool for optimizing larval production. This study’s goals were to investigate the microbiome stability of a RAS rearing oyster larvae across time and space, determine impacts of larval presence on the microbiome, and examine connections between larvae production outcomes and microbiome stability. Water samples were collected weekly from four compartments in the Thad Cochran Marine Aquaculture Center’s RAS at the University of Southern Mississippi during three runs spanning May-October 2019 (168 days), June-October 2020 (115 days), and May-October 2021 (165 days). Sequencing was done using the V6-V8 variable regions of the 16S rRNA gene targeting bacteria. Water quality parameters and larval survival-assessments were collected. The RAS achieved stable physiocochemical conditions and microbiomes by the third run. Each compartment, with a specific function in water-reclamation/larval rearing, contained distinct microbiomes. Larval presence was not a factor shaping any compartment’s microbiome. Connections between larvae and the Raceway (first water-reclamation stage) microbiome elevated over time, and instability loosely correlated with declining larval performance. Establishing baseline microbiomes present in closed-systems and further exploring connections between production and RAS microbiomes would enhance knowledge of RAS microbiome dynamics. The better the RAS microbiome is understood, the more valuable a tool in aquaculture it can be.

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