Prevalence and environmental determinants of Black Gill Disease in Penaeid shrimp within Pamlico sound.
| dc.contributor.advisor | April Blakeslee | |
| dc.contributor.author | Gabriel, Chloe Elizabeth | |
| dc.contributor.committeeMember | James Morley | |
| dc.contributor.committeeMember | Rachel Gittman | |
| dc.contributor.committeeMember | Amy Fowler | |
| dc.date.accessioned | 2024-08-29T14:16:11Z | |
| dc.date.available | 2024-08-29T14:16:11Z | |
| dc.date.created | 2024-07 | |
| dc.date.issued | July 2024 | |
| dc.date.submitted | July 2024 | |
| dc.date.updated | 2024-08-27T19:14:00Z | |
| dc.degree.college | Thomas Harriott College of Arts and Sciences | |
| dc.degree.department | Biology | |
| dc.degree.grantor | East Carolina University | |
| dc.degree.major | MS-Biology | |
| dc.degree.name | M.S. | |
| dc.degree.program | MS-Biology | |
| dc.description.abstract | Penaeid shrimp are one of the most ecologically and economically important species in North Carolina estuaries as well as the whole Southeastern United States. These species have historically brought in large amounts of revenue to North Carolina; in 2022, the shrimp fishery brought in over 10 million dollars to the State. Penaeid shrimp also serve other fisheries by being an important prey item for economically and ecologically important fish species like Flounder and Drum. As penaeid shrimp are ecologically and economically important, it is imperative that any threats to local shrimp populations are tracked. A recent threat to penaeid shrimp in the Southeast U.S. is a parasitic illness called Black Gill Disease. In the southeastern U.S., Black Gill Disease is the result of melanization and inflammation of shrimp gill tissue as a result of an infection by a parasitic ciliate species Hyalophysa lynni. Hyalophysa lynni is assumed to be native to the Gulf of Mexico, but has expanded its range northward, potentially facilitated by climate change, where warming temperatures have created more favorable conditions at its northernmost ranges. With the recent appearance of black gill disease in North Carolina, detection methods must be accurate to avoid underestimation of black gill impacts on the shrimp population and increase understanding of the disease impacts in this area. In chapter 1 of this thesis, two methods of detection (microscopy and genetics) are compared to determine the most efficient and accurate approach to identify infected shrimp. These methods are also discussed within the context of the current “on the boat” monitoring efforts conducted by the North Carolina Division of Marine Fisheries during the P195 survey. I hypothesized that a combination of microscopy and molecular techniques would provide the most accurate estimation of black gill disease prevalence. I found microscopy to be both efficient and accurate in detecting all stages of infections as well as being a more affordable and time efficient detection method when compared to PCR. Statistical analysis supported that there was not much difference between detection methods in their abilities to quantify black gill disease prevalence. Based on sequence data, my work successfully confirmed the cause of sBG in Pamlico Sound to be the ciliate Hyalophysa lynni, the same species that is suspected to be the cause of sBG in other states. Moreover, my data showed that microscopy and PCR results strongly aligned with one another (97% agreement). In Chapter 1, I also applied microscopy-based prevalence data to describe spatial and temporal patterns of black gill disease in Pamlico Sound as observed throughout the project. I also designed a descriptive black gill severity scale, which can be used to assist in future projects and aid fishery agencies in their monitoring efforts by standardizing severity scales. By determining the most accurate and efficient black gill disease detection method, projects and fishery-based agencies can apply these methods to increase their understanding and accurate monitoring of the disease. In chapter 2 of my thesis, I aimed to fill a knowledge gap regarding how white shrimp Penaeus setiferus respond to lower salinities and abrupt declines in salinity. To do so, I conducted an experiment exposing shrimp to varying low salinities and monitoring them for common stress behaviors and survival. Penaeus setiferus (commonly referred to as “white shrimp”) occurs in the Atlantic from the Chesapeake Bay to the Gulf of Mexico and is a common fishery for many of these states. This species of Penaeid shrimp moves between brackish estuaries and ocean waters at specific life stages. Due to this movement, it is generally assumed that Penaeus setiferus has a relatively broad salinity tolerance range, though there is a lack of literature describing how well it survives and responds to low salinities. My experiment exposed white shrimp from Eastern NC to three low-end salinities (2ppt, 5ppt, 15ppt) to determine if there were significant survival and behavior changes. I hypothesized that lower salinities would result in higher mortality rates and increased stress behaviors. I observed that shrimp placed in 15 ppt treatments showed the least mortality and stress behaviors while shrimp placed in 2 ppt showed the highest mortality and stress behaviors. These results could be important for understanding changing salinity levels in estuaries as a result of climate change and increases in episodic storm events, and the ways that species may respond to these rapid changes. | |
| dc.format.mimetype | application/pdf | |
| dc.identifier.uri | http://hdl.handle.net/10342/13706 | |
| dc.language.iso | English | |
| dc.publisher | East Carolina University | |
| dc.subject | Biology, Ecology | |
| dc.title | Prevalence and environmental determinants of Black Gill Disease in Penaeid shrimp within Pamlico sound. | |
| dc.type | Master's Thesis | |
| dc.type.material | text |