Variability in fatty acid composition of bottlenose dolphin (Tursiops truncatus) blubber as a function of body site, season, and reproductive state

Abstract

Odontocete blubber has been shown to be variable in composition and can be separated into strata visually, histologically, and biochemically. The purpose of this study was to examine fatty acid composition of bottlenose dolphin (Tursiops truncatus (Montagu, 1821)) blubber, and determine if differences exist between body sites, reproductive states, and (or) seasons. The influence of these variables on blubber composition could aid in the creation of a model that would use fatty acid signature analysis to evaluate diet in free-ranging populations. Blubber samples were obtained from freshly dead animals along the Texas and Louisiana coastlines. Samples from nine body sites were analyzed to investigate site variability, and from one site to evaluate differences due to season, reproductive state, and blubber layer. All body sites of animals sampled in the winter were statistically indistinguishable, indicating that biopsy samples could be obtained from any location on the animal for fatty acid analysis during this season; however, three distinct blubber layers were identifiable, and reproductive states were significantly different in terms of fatty acid composition. Seasonal differences in fatty acid composition were also highly significant for all one-site inner blubber layer samples. Ultimately, the differences in fatty acid composition could have resulted from dietary or physiological factors and need to be examined further.