Feeding ecology of leopard seals by way of fatty acid signature analysis
In spite of the remoteness of Antarctica, this continent is suffering the effects of global changes. While the East Antarctic ice sheet has remained relatively stable, the West Antarctic landmass has experienced a drastic warming. Pack-ice seals are among organisms potentially affected by global warming, since their habitat is likely to be impacted, which can lead to cascading effects. For instance, leopard seals are highly dependent on pack-ice; they are considered top generalist predators, since they behave opportunistically, in such a way that they may change their diet in response to changes in availability of different prey types. Therefore, their diet might reflect what is available and hence warn about possible changes in the ecosystem.
Nevertheless, the study of marine mammals is particularly challenging since they feed at sea, sometimes traveling long distances, and experience periods of variable intakes. Consequently, biochemical methods, such as fatty acid analysis, have been developed in order to understand the feeding ecology of marine mammals.
Once a marine mammal prey on a particular organism, fatty acids from prey are transferred conservatively through the digestive process and remain intact in the predator blubber. Specific fatty acids can be indicative of particular prey types. Thereby lipids can be utilized as trophic markers to obtain information about diet. Analysis of fatty acids compounding blubber could provide information over periods of weeks to months, which are ecologically more significant than traditional methods.
In this study I aim to obtain dietary information of leopard seals using fatty acid analysis. The study will be focused on populations from Eastern and Western Antarctica in order to see how these populations are facing the changing climatic conditions.
Supervisor - Associate Professor Tracey Rogers
Co-Supervisor - Dr Adriana Verges
