The diets of green turtles from five dissimilar aggregations of juvenile C. mydas on the East Coast of Florida were analyzed. C. mydas were captured by tangle net from four of the study sites and a dietary sample was collected by an esophageal flushing technique. The gut content of stranded individuals was collected for the fifth site. The vegetation in these study areas differs in varying degrees of abundance and diversity. Analysis of the samples revealed the alga types preferred by green turtles from each population and provided the basis for examination of similarities and differences in their diets.
Large numbers of the juvenile C. mydas worldwide are infected with a disease called Fibropapillomatosis (FP). The herpes-type virus that appears to cause the disease manifests as tumors normally on the fleshy parts of the body. The placement and size of the tumors can eventually impede the green turtle’s ability to swim and forage. Severe conditions of the disease lead to death either by starvation or the inability to evade predators. While the herpesvirus initiates FP, there are other environmental cofactors that may play a role in promoting the disease. Some toxic microalgae (dinoflagellates) of the genus Prorocentrum produces a known tumor promoter called okadaic acid. The acid has been shown to promote cutaneous tumors in laboratory mice. These Prorocentrum species live primarily as epiphytes, forming a mucilaginous attachment to seagrasses and macroalgae. Chelonia mydas may be consuming the toxic microalgae when they forage on vegetation.
Samples of available vegetation at each study area were collected and examined to determine if C. mydas were potentially consuming Prorocentrum. Prorocentrum were quantified for diet items by counting the number of cells per wet weight of macroalgae. In most cases, the diet analysis and microalgae quantification results showed an association between the consumption of substrates utilized by Prorocentrum spp and a high prevalence of FP in that population.
Ehrhart, Llewellyn M.
Master of Science (M.S.)
College of Arts and Sciences
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Masters Thesis (Open Access)
Arts and Sciences -- Dissertations, Academic; Dissertations, Academic -- Arts and Sciences
Holloway Adkins, Karen Gayle, "A comparative study of the feeding ecology of Chelonia mydas (green turtle) and the incidental ingestion of prorocentrum spp" (2001). Retrospective Theses and Dissertations. 1207.
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