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.

Identifying the Eastern Oyster Growing Season in Rehoboth Bay, Delaware

Aragonite Saturation as an Indicator for Oyster Habitat Health in Delaware Inland Bays Amin Boukari1, Memory Nakazwe2, and Gulnihal Ozbay2, Ph.D. 1Cesar Rodney High School, Dover, DE 2Delaware State University, Department of Agriculture and Natural Resources, Dover, DE Oyster farming in Delaware is a crucial industry and it makes about $300,000 to $500,000 in sales every year. Oysters use calcium carbonate ions in the form of aragonite and calcite to build their shells. Ocean acidification can lead to a decrease in carbonate ions making building these shells difficult. When the aragonite saturation state falls below 3, calcifying organisms become stressed, and when it drops below 1, their shells begin to dissolve. Therefore, measuring the aragonite saturation state yields crucial insight into the suitability of habitats to support oyster growth. This project aimed to calculate the aragonite saturation state from seven sites in Delaware Inland Bays to determine their feasib

Aragonite Saturation as an Indicator for Oyster Habitat Health in Delaware Inland Bays

Investigating Oyster Health Status by Studying Oyster Condition Index and Natural Oyster Sets in Rehoboth Bay, Delaware Sara Berzinji1, Aaron Bland2, Memory Nakazwe2, Mohana Gadde2, and Gulnihal Ozbay2, Ph.D. 1Ransom Everglades High School, Miami, FL 2Department of Agriculture and Natural Resources, Delaware State University, Dover, DE Over the past few decades, oyster (Crassostrea virginica) populations have been in decline. One of the many bodies of water affected by this is the Rehoboth Bay. This research focuses on assessing the health of oysters placed in seven different sites along the Bay. Assessing which locations are thriving will help in creating more successful artificial reefs and therefore lead to healthier aquatic ecosystems. While there is a large issue with oyster populations, this research focused on those in the Rehoboth Bay. Bags with oysters were deployed at each of the seven sites in the early summer of 2020 and were collected 5-6 weeks later. This process was repeated two more times, in late summer and then in the fall of 2020. Spats were counted and the condition index was calculated by measuring the height, width, and depth of the oysters along with the weight of their shells and tissue dry and wet. Calculating the condition index and counting the number of spats help determine if the oysters were healthy. The condition index remained generally constant throughout the 3 testing periods and the recruitment rates at each site were also constant with the exception of the BBR site which had a higher average number of spat along with the S Cove site. These results can be used to create healthy and successful oyster reefs in the Rehoboth Bay and better the health of the ecosystem. Keywords: oyster restoration, oyster recruitment, condition index, Rehoboth Bay, Crassostrea virginica 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.

Eastern Oysters (Crassostrea virginica) Health Assessment in the Rehoboth Bay

Examining Water Quality and Blue Crabs (Callinectes sapidus) Gut Content in Blackbird Creek, Delaware State University Kayla McKinley, Jackie Maina, and and Gulnihal Ozbay, Ph.D. Department of Agriculture and Natural Resources, Dover, DE Department of Agriculture and Natural Resources, Delaware State University, Dover, DE, 19901 Blue crabs are an important part of the Delmarva local economy. They bring in revenues amounting to 4 to 6 million dollars annually. Blue crab habitat use is dependent on life cycle stage. Marsh habitats are especially essential for juvenile blue crabs as they provide shelter from predators. Marsh dynamics are influenced by nutrient input, affecting their ability to support crab populations. The objective of this study was to examine water quality conditions and investigate blue crab feeding behavior in Blackbird Creek, Delaware. Five sites were identified based on dominant vegetation. Site 1: Sporobolus alterniflora and Phragmites australis. Site 2: S. alterniflora and Sporobolus cynosuroides. Site 3:S. alterniflora, S. cynosuroides and P. australis. Site 4: S. alterniflora.Site 5: P. australis. As 51% of the land surrounding Blackbird creek is agricultural land, water quality monitoring targeting nitrogen and phosphorus nutrients was conducted in 2017 and 2020 to determine the creek’s suitability as a blue crab habitat. Fifty-two crabs in total were collected using crab traps. Percentage gut fullness and volume were determined. The preliminary results indicate that the highest mean nitrate, nitrite, ammonia and orthophosphates were from sites 5 (0.44 mg/L) site 2 (0.0136 mg/ L), site 5 (0.068 mg/ L) and site 1 (0.498 mg/ L) respectively. All the nutrients were within Delaware’s regulatory ranges for surface water quality. The crab gut content analysis indicates that the highest percentage fullness mean (75%), and the highest gut volume mean (4.57 mL) were from site 5. The water quality values are almost similar across sites, and they are unlikely to influence blue crab feeding habits in Blackbird Creek. The vegetation is therefore the most likely determinant of food availability in this habitat meaning that although P. australis is an invasive species, it provides a better feeding environment for the blue crabs. Keywords: Blue crab, Gut content, Blackbird Creek, Water quality, Marsh grass Acknowledgements: We acknowledge USDA NIFA Capacity Building Grant Awards# 2016-06642 and 2016-06476 for funding my internship and the project as part of the student experiential learning goal and the Project Director, Dr. Gulnihal Ozbay, and the Project Director, Dr. Shobha Sriharan, respectively for providing this internship opportunity.

Examining Water Quality and Blue Crab Gut Content in Blackbird Creek

This project involves assessing the amount of Vibrio spp. in seawater at Slaughter Beach, Delaware. Vibrios are bacteria that thrive in warm seawater and are highly pathogenic to humans and oysters. The four species that we seek to identify are V. vulnificus, V. parahaemolyticus, V. coralliilyticus, and V. tubiashii. Monitoring the level of Vibrio and environmental parameters such as salinity, temperature, and turbidity help managers determine whether Slaughter Beach is an acceptable location for a future oyster hatchery. The objectives for this project are to investigate total V. vulnificus, V. parahaemolyticus, V. coralllilyticus, and V. tubiashi in seawater, and to determine the relationship between the water quality parameters and level of Vibrio spp. Water samples were collected bimonthly in June and July 2021. The YSI 556 multi probe was used to monitor salinity and temperature, and turbidity was monitored using the Global Water WQ770 turbidimeter at two sites (The Slaughter Beach Boat Ramp and Cedar Creek) during high and low tide. Thiosulfate Citrate Bile Salts Sucrose (TCBS) is the agar used to monitor Vibrio growth and 100 μL of seawater were inoculated at 26 ℃ and 37 ℃. The turbidity level at the Boat Ramp was higher than at Cedar Creek during both tides from June to July. At both tides, salinity was low, but Cedar Creek had greater amounts of Vibrio spp., with more salinity and higher temperature than at the Boat Ramp. This suggests that Vibrio may grow more in seawater at low salinity, high turbidity, and temperature. Monitoring these Vibrio spp. and water quality parameters can aid in reducing human and oyster infections.

Analyzing the Total Level of Vibrio spp. in Seawater at Slaughter Beach, Delaware

Examining Differences in Water Quality and how it Affects Oyster Growth in Rehoboth Bay, Delaware Kevin Knight, Aaron Bland and and Gulnihal Ozbay, Ph.D. Department of Agriculture and Natural Resources Delaware State University, Dover, DE Rehoboth Bay, one of the three Delaware Inland Bays, is a site of recently implemented oyster aquaculture and oyster artificial reefs. Oyster aquaculture is the farming of oysters to eat and artificial reefs help restore the wild oyster population. Oysters, both wild and farmed, help filter nutrients in the water and provide habitat to fishes and invertebrates. Oysters in Rehoboth Bay may help manage the excessive nutrient pollution affecting the Bay. Water quality can affect oyster growth, but it is not clear whether water quality changes across the Bay. This information could help oyster farmers and conservation managers find the best areas for oysters to grow. The objectives of this project are to figure out if throughout the bay there are major differences in water quality and whether those differences may impact how oysters grow. To test the hypothesis that there would be significant differences in water quality across Rehoboth Bay, seven sites in Rehoboth Bay were visited approximately every two weeks, weather permitting, from July to November 2020. Sites were either an aquaculture site, artificial reef site or a control site without oysters. Water quality was determined using a YSI 556 multiprobe system, an AquaFluor Handheld Fluorometer, and a Global Water WQ770 Turbidimeter, taking three readings per site visit. Collected water samples were filtered through a pre-weighed filter to determine Total Suspended Solids (TSS). Temperature, TSS, chlorophyll, and dissolved oxygen were the main factors used to determine whether or not the hypothesis was correct. The data were averaged out for each site by each month. Four two-factor ANOVA tests were used to determine if there were significant differences in the parameters between the months and across sites. It was determined that, for each parameter, there was a significant difference by month and site. Differences between months were generally greater than those across sites. Based on literature values, it is unlikely that there would be significant differences in oyster growing suitability across the different sites. Keywords: Rehoboth Bay, Oysters, Aquaculture, Artificial Reefs, Water Quality Acknowledgements: We acknowledge USDA NIFA Capacity Building Grant Awards# 2016-06642 and 2016-06476 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.

Examining Differences in Water Quality and How it Affects Oyster Growth in Rehoboth Bay, DE

Artificial Oyster Reefs and Oyster Farms Impact on Recruitment, Species Diversity, and Water Quality in Rehoboth Bay, Delaware

Artificial Oyster Reefs and Oyster Farms Impacts on Water Quality, Species Diversity, and Recruitment in Rehoboth Bay

Sperm whales (Physeter macrocephalus) are cetaceans with a worldwide distribution and a complex social structure. Sperm whales are members of cultural groups, called “vocal clans”. Members of a vocal clan have a distinctive suite of socially learned social calls, and do not associate with individuals from other vocal clans. However, whether vocal clan membership has implications beyond the use of a characteristic acoustic repertoire had never been tested in the Caribbean. Via a dedicated survey of sperm whales in the Lesser Antilles, we observed stark differences in vocal clan distributions across relatively small distances (<100km), with little to no overlap between them. These differences in distribution appear to relate to environmental variables with one vocal clan preferring island channels and areas of high eastward current speed and the other preferring canyons with low meridional velocity variance. Such fine-scale habitat partitioning is surprising for a species which is often referred to as an “ocean nomad” and contrasts with Eastern Tropical Pacific clans, which share habitats over much greater scales (we observe a factor of 10 difference between the movements of Eastern Caribbean and Eastern Tropical Pacific sperm whales). We hypothesize that Eastern Caribbean sperm whales are habitat specialists, with vocal clans specializing on the use of certain environmental features and maintaining this specialization through social learning. This not only highlights the need to incorporate culture in the field of conservation management, as different cultural groups have different distributions and habitat use, but also the inherent ties between culture and the environment.

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Identifying the Eastern Oyster Growing Season in Rehoboth Bay, Delaware

Aragonite Saturation as an Indicator for Oyster Habitat Health in Delaware Inland Bays

Eastern Oysters (Crassostrea virginica) Health Assessment in the Rehoboth Bay

Examining Water Quality and Blue Crab Gut Content in Blackbird Creek

Analyzing the Total Level of Vibrio spp. in Seawater at Slaughter Beach, Delaware

Examining Differences in Water Quality and How it Affects Oyster Growth in Rehoboth Bay, DE

Artificial Oyster Reefs and Oyster Farms Impacts on Water Quality, Species Diversity, and Recruitment in Rehoboth Bay

Culture impacts the distribution and habitat use of sperm whales in the Eastern Caribbean

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