Laurie Meyer

4-3-03

Lipid content and composition of adipose tissue as an indicator of sea turtle health

Abstract:

Current health assessment methods of sea turtles are inadequate. Two commonly used health indices involve total mass and dissectible lipid mass respectively. These indices are based on the assumption a healthier turtle will have a larger total body mass or adipose mass relative to length than a less healthy turtle. However, turtle necropsies have shown that turtle adipose tissue can be edematous increasing the weight of the adipose tissue and overall turtle weight. This makes the sea turtle appear healthier than if it did not have edema, and health assessment methods must be developed which account for this edema. The purpose of this study was to determine if percent lipid and fatty acid (FA) composition is indicative of turtle health. The lipid content and FA composition of adipose from sea turtles found dead or euthanized by the Virginia Aquarium Stranding Project (VASP) was determined through lipid extraction and gas chromatography. Frozen samples were obtained from 19 specimens of the loggerhead sea turtle (Caretta caretta), Kemp’s Ridley (Lepidochelys kempii), and leatherback sea turtle (Dermichelys coriacea). Percent lipid and FA composition of appendage, carapace, coelomic, and plastron depots were compared between species and between body condition classes and causes of death in C. caretta. It was found that percent lipid was indicative of body condition in C. caretta and that percent lipid and FA were not correlated with cause of death due to the compounding influence of illness. Data analysis also showed that D. coriacea had a much higher percent 12:0 fatty acid composition than the other two species. A larger sample size and the addition of samples from healthy turtles would decrease sampling error, facilitate further statistical testing, and increase outcome applicability. Data from more turtles, especially known healthy specimens, would be necessary to determine if FA composition may be used to develop a health index for sea turtles.