HCNSO Student Theses and Dissertations

Defense Date

4-27-2018

Document Type

Thesis

Degree Name

M.S. Marine Environmental Sciences

First Advisor

Nicole Fogarty

Second Advisor

Esther C. Peters

Third Advisor

Erinn Muller

Abstract

Unprecedented population losses of the staghorn coral, Acropora cervicornis, since the 1970s have been attributed primarily to disease. Although a positive linear relationship between disease prevalence and increased water temperature has been described, the pathogen(s) causing disease and whether they are spread through the water or vectors is still poorly understood. Additionally, an increase in disease outbreaks and severity has provided an urgent need to identify natural genotypic resistance to disease in Caribbean acroporids. Studies to date have explored a variety of pathogen transmission methods, but prior to this study, there has been no examination of differences among common techniques. I investigated pathogen transmission and resistance to development of the disease known as rapid-tissue loss (RTL) in 11 different genotypes by comparing two common transmission methods (direct contact vs. waterborne). Additionally, I investigated changes in tissue condition over a 9-day acclimation period to determine the potential effect of acclimation on disease susceptibility. Overall, disease was significantly higher in the direct contact treatment, though resulting disease varied greatly by genotype, with only one genotype appearing resistant to developing disease. Acclimation time influenced tissue condition with a significant decline in condition occurring from day zero to day two, but significant improvements in surface body wall parameters were observed from days two to nine. These results highlight the differences between disease transmission methods and demonstrate the importance of selecting an appropriate transmission method and acclimation period for future studies.

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