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Fatty acid composition and distribution in the blubber of bottlenose dolphins (Tursiops truncatus)
Abstract
Bottlenose dolphin (Tursiops truncatus) blubber is heterogeneous, and divided into sub-epidermal, middle, and deep layers. This is consistent with other studies that have shown how odontocete blubber is variable in composition, and can be separated into strata visually, histologically, and biochemically. Fatty acid signature analysis has been used in determining dietary history of marine mammals. It is also an excellent tool for examining differences in fatty acid composition of blubber between seasons, genders, and layers at various sites along the body. Foraging ecology of cetaceans has not been studied extensively, and little information exists about their body composition. The purpose of this study was to determine if differences in fatty acid composition exist between seasons, genders, and blubber layers along the body of bottlenose dolphins and to investigate the potential use of fatty acid signature analysis to discern diet of small cetaceans. Blubber samples were obtained from fresh-dead bottlenose dolphins along the Texas and Louisiana coastlines. Twenty-two animals were sampled, including males, non-lactating females, and lactating females, from summer and winter seasons. Samples from nine different sites along the body were examined. Lipids were extracted from each sample, and fatty acid methyl esters analyzed using a gas-liquid chromatograph connected to a computerized integration system. Statistical analysis consisted of multivariate techniques, including classification and regression trees (CART). Seasonal, gender, and layer-related differences were present with varying degrees of significance. Season was the strongest separating variable for all samples, followed by gender, layer, surface, and finally body site. Season, gender, and layering effects have been well documented in other studies. These changes probably result from dietary factors, as well as selective fatty acid mobilization and utilization to accommodate blubber functions such as energy storage, insulation, and streamlining. Because little variation existed between sampling sites and surfaces, it will be possible to obtain biopsy samples from any location anterior to the anus on the animal for future analysis. It may be difficult to interpret fatty acid signatures until further information is known about the feeding patterns and turnover rates in bottlenose dolphin blubber because other factors besides diet can affect fatty acid composition.
Description
Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to digital@library.tamu.edu, referencing the URI of the item.Includes bibliographical references (leaves 75-83).
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Citation
Samuel, Asha Melina (2000). Fatty acid composition and distribution in the blubber of bottlenose dolphins (Tursiops truncatus). Master's thesis, Texas A&M University. Available electronically from https : / /hdl .handle .net /1969 .1 /ETD -TAMU -2000 -THESIS -S252.
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