Aquaculture America 2023

February 23 - 26, 2023

New Orleans, Louisiana USA

EASTERN OYSTERS RESTORATION, RECRUITMENT, AND THEIR IMPACT ON SPECIES DIVERSITY AND WATER QUALITY IN REHOBOTH BAY, DELAWARE

Marcus Teat*, Jacqueline Maina, Theresa Venello, Ph.D., Gulnihal Ozbay, Ph.D.

 

Department of Agriculture and Natural Resources, Delaware State University, Dover, Delaware, 19901

mnteat16@students.desu.edu

 



Rehoboth Bay, Indian River Bay, and Little Assawoman Bay are part of Delaware’s Inland Bay system. Rehoboth Bay spans thirteen square miles and is connected to the Indian River Bay in the south, the Lewes-Rehoboth Canal to the north, and other freshwater bodies. Eastern oyster (Crassostrea virginica) populations in the bays have decreased due to overharvesting and disease. Without eastern oysters, nutrient-rich water increases concentration and frequency of algal blooms that can result in areas in the bays that can cause a reduction in dissolved oxygen and lower the chance for marine wildlife to survive. However, eastern oysters’ ability to be natural filter feeders may help control nutrient levels and improve water quality, species diversity, and the productivity of fisheries.

The objective of this project is to understand how artificial oyster reefs and aquaculture farms can affect water quality, species diversity, and oyster recruitment in Rehoboth Bay. Two artificial oyster reefs, two oyster farms, two control sites, and one former oyster farm were chosen. Four oyster shell bags were deployed at every site. These bags are left in the bay for five weeks before being retrieved. Each site is also monitored by a YSI 556 Multiprobe to collect dissolved oxygen data. Water samples are also collected and processed in the lab for nitrate and orthophosphate levels. 2021 results from Dr. Ozbay’s lab show that artificial and oyster farms have the highest oyster recruitment and species richness, and species abundance, while oyster farms had the highest species diversity. 2022 field data is currently being analyzed.

Keywords: Eastern oyster, recruitment, diversity, water quality

Acknowledgments: We acknowledge NOAA LMRCSC Grant #NA16SEC4810007, National Science Foundation EPSCoR Grant No. 1757353 and the State of Delaware, and Dr. Gulnihal Ozbay’s One Health Lab team