Graduation Year


Document Type




Degree Granting Department

Marine Science

Major Professor

Norman J. Blake, Ph.D.

Co-Major Professor

Pamela Hallock Muller, Ph.D.

Committee Member

Bruce J. Barber, Ph.D.


Dermo, Disease, Histology, MSX, Pathogen



Five sites in Tampa Bay, Florida, were sampled monthly from February 2006 to January 2007. These sites were located at the mouth of the Alafia River, in an inlet of Cross Bayou, on the easement of Gandy Bridge, near mangrove in Manatee County, and an inlet of Salt Creek, off Bayboro Harbor. Standard methods were used to determine shell height and Condition Index (CI). Intensity and prevalence of Perkinsus marinus were analyzed using Ray's Thioglycollate medium test, while Haplosporidium nelsoni was studied by histological examination. Histological methods were also used to determine sex ratios, reproductive phases, and egg diameters.

Perkinsus marinus was identified at all sites, exhibiting a bimodal seasonality, with maximum intensity and prevalence in late winter and late summer, and with minima in late spring and late autumn. No evidence for H. nelsoni infections was found in any of the 1800 specimens examined. Condition Index also exhibited seasonal bimodality with higher CI values found in specimens collected in late spring and late autumn. Cross Bayou and Salt Creek sites were distinct from each other and from the other sites with respect to parameters assessed, while oyster populations at the Alafia, Gandy and Manatee sites were similar. Overall, this study supports previous hypotheses that southeastern oyster beds do not experience temperatures or salinities low enough to induce dormancy in P. marinus; thus, it is prevalent throughout the year.