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Comparison of Perkinsus marinus infection and oyster condition in southeastern North Carolina tidal creeks

UNCW Author/Contributor (non-UNCW co-authors, if there are any, appear on document)
Sara L. Colosimo (Creator)
Institution
The University of North Carolina Wilmington (UNCW )
Web Site: http://library.uncw.edu/
Advisor
Martin Posey

Abstract: The Eastern oyster (Crassostrea virginica) is a commercially important species that also performs critical ecosystem functions, affecting water quality and providing habitat for fish and invertebrates. However, populations of C. virginica have drastically declined, especially over the last 50 years. In recent years, disease caused by the protozoan parasite, Perkinsus marinus (Dermo), has been a major factor contributing to the decline of oyster populations. Exposure to one or more environmental stressors, such as increased particulate loading and declining water quality, may adversely affect oysters, making them more susceptible to infection. This study compares P. marinus infection in intertidal oysters from three tidal creeks in southeastern North Carolina that vary in historic water quality conditions. Prevalence and intensity of P. marinus infection was compared over time and among creeks for both natural oyster populations and hatchery stock outplants using RFTM tissue assay. Oyster tissue condition, growth, and mortality were also compared. Infection was nearly 100% prevalent across sampling periods, among creeks, and in both hatchery and natural oysters. However, despite high prevalence, overall infection intensities were low. Infection intensity among the creeks did not follow historic water quality patterns, but did vary with specific factors. Temporal patterns of P. marinus infection and tissue condition were apparent in both hatchery and natural oysters. Infection intensities were highest and oyster condition was lowest during November 2005 while infection was at its lowest and condition was at its highest in February 2006. Infection levels and condition also differed between oyster types with hatchery oysters having higher infection intensity and lower condition than natural oysters. Infection intensity and oyster condition were also correlated with aspects of water quality in the tidal creeks. The results of this study have implications not only for restoration, but also for understanding oyster and parasite biology in the intertidal environment. They suggest that conditions of the intertidal environment may impact seasonal cycles of P. marinus infection in the southeastern United States and may even affect the parasite itself. Overall, the results underscore the idea that a variety of factors likely interact to influence P. marinus infection levels in oysters and oyster health.

Additional Information

Publication
Thesis
A Thesis Submitted to the University of North Carolina at Wilmington in Partial Fulfillment of the Requirement for the Degree of Masters of Science
Language: English
Date: 2009
Keywords
Oysters--Diseases--North Carolina, American oyster--Diseases
Subjects
Oysters -- Diseases -- North Carolina
American oyster -- Diseases