Identifying the Eastern Oyster Growing Season in Rehoboth Bay, Delaware

Abstract

Identifying the Eastern Oyster Growing Season in Rehoboth Bay, Delaware Jannah Zerrad1, Aaron Bland2, and and Gulnihal Ozbay2, Ph.D. Caesar Rodney High School, Camden Wyoming, Delaware1 Department of Agriculture and Natural Resources, Delaware State University, Dover Delaware2 Eastern Oysters, Crassostrea virginia, are valued for their culinary and ecosystem functions, such as improving water quality and providing habitat. Wild oysters have recently struggled to maintain their population in Rehoboth Bay, Delaware due to overharvesting and disease. However, oyster aquaculture farmers have recently begun to grow oysters in Rehoboth Bay, selling to restaurants and households. In addition, artificial oyster reefs were made in Rehoboth bay to increase the wild Eastern Oyster population. The observations of water quality are essential for identifying which dates are the best or worst in the given sites for oysters to survive and grow, both for aquaculture and restoration activities. Water samples were collected from seven sites every two weeks in Rehoboth Bay, Delaware. Measurements of temperature, salinity, and dissolved oxygen were obtained using the YSI 556 multiprobe. Lastly, Chlorophyll a was measured using the Aquafluor Fluorometer. Trendlines for temperature, salinity, dissolved oxygen, and chlorophyll from each of the seven sites were calculated and graphed. We found that the beginning of August-late September were the best times for ideal temperature conditions for Eastern Oysters. Mid-August and later November were found to be good salinity conditions while all sites were suitable conditions for dissolved oxygen in early August-late November. It was also found that all sites were lower in chlorophyll a than expected, suggesting there may be less algae than ideal for oyster growth. The overall best times for growing Eastern Oysters in Rehoboth Bay, Delaware would have been mid-August to late September. These findings may help oyster farmers and conservation managers improve their oyster rearing activities in Rehoboth Bay. Keywords: Dissolved oxygen, Salinity, Chlorophyll, Temperature, Eastern Oyster, Rehoboth Bay Acknowledgments: We acknowledge USDA NIFA Capacity Building Grant Award# 2016-06642 for funding my internship and the project as part of the student experiential learning goal and the Project Director, Dr. Gulnihal Ozbay for providing this internship opportunity.