Comparison of pinniped and cetacean prey tissue lipids with lipids of their elasmobranch predator.

BACKGROUND: The great white shark is known to include pinnipeds and cetaceans in its diet. Both groups of marine mammals deposit thick blubber layers around their bodies. Elasmobranchs do not produce adipose tissue, but rather store lipid in their livers, thus a great white predating on a marine mammal will deposit the lipids in its liver until required. MATERIALS AND METHODS: Samples from great white liver and muscle, Cape fur seal, Indian Ocean bottlenose dolphin and common dolphin liver, muscle and blubber were analyzed for their lipid and fatty acid profiles. RESULTS: The great white liver and marine mammal blubber samples showed a considerable degree of homogeneity, but there were significant differences when comparing between the muscle samples. Blubber from all three marine mammal species was calculated to provide greater than 95% of lipid intake for the great white shark from the tissues analyzed. CONCLUSION: Sampling of prey blubber may give a good indication of the lipids provided to the shark predator.