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Schubert – The effects of pathogenic Vibrio species on Eastern Oyster mortality events in North Carolina aquaculture

 

The effects of pathogenic Vibrio species on Eastern Oyster mortality events in North Carolina aquaculture (2024)

Undergraduate: Zoe Schubert


Faculty Advisor: Rachel Noble
Department: Earth, Marine, and Environmental Sciences

Shellfish Aquaculture is an essential part of North Carolina’s economy. However, the industry faces multiple challenges stemming from anthropogenic and environmental stressors, notably climate change-induced weather events, water pollution, and infection from pathogenic bacteria such as Vibrio species. This paper investigates the influence of Vibrio spp. presence in the water column on Eastern Oyster (Crassostrea virginica) mortality. With rising sea temperatures, concerns about mortality events related to Vibrio spp. infection have escalated due to their increased abundance and altered virulence expression. This study aims to uncover the mechanisms by which Vibrio spp. affect oyster health and mortality rates. _x000D_
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An experiment was conducted using four raceway tanks, two challenged with a Vibrio inoculum and two controls. Oysters were monitored over 29 days, with water and oyster samples collected at eight time points. Molecular analyses via droplet digital PCR (ddPCR) and bacterial culture were employed to detect Vibrio concentrations in water samples. Results indicated significant variance in Vibrio concentrations over time. The presence of Chitinase D1 (ChiD1), specific to Vibrio spp., demonstrated bacterial proliferation in the oyster microbiome after ingestion and subsequent release. Analysis suggested active uptake and release of bacteria by oysters, potentially contributing to Vibrio proliferation in the water column. _x000D_
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This study provides insights into the dynamics of Vibrio infection within oyster populations and emphasizes the need for further investigation considering varied inoculation levels and environmental factors. Understanding these interactions is crucial for mitigating mortality events in shellfish aquaculture, offering strategies to manage water quality-related threats in oyster farming.