1st AATAMS CTD tag has been successfully deployed on a seal at Macquarie Is
The first of 15 AATAMS/IMOS CTD tags has been successfully deployed on an adult female elephant seal at Macquarie Island by a team lead by Dr Iain Field from Macquarie University. The CTD tags were funded as part of the Education Investment Fund (EIF) enhancement to IMOS. The data will be used in a collaborative research programme between leading researchers Prof Rob Harcourt, from Macquarie University, and Prof Mark Hindell from the University of Tasmania. Over the past decade is it clear that Antarctica and the surrounding Southern Ocean is changing at an unprecedented rate due to climate change. This is likely to have profound consequences for both the ecosystem and the environment, which strongly influences the climate in Australia. Yet precise measures of these changes and how animals respond to them has previously proven extremely difficult to measure. Over the course of the Antarctic summer, it is planned to equip 30 seals with these CTD tags, from the subantarctic Macquarie Island and Casey Station in Antarctica to observe ecosystem level and physical ocean interactions.
Southern elephant seals are large predators that forage in the Southern Ocean covering a wide geographical range. They are major consumers of biomass and are likely to be affected by variation in food availability. At the moment the seals have returned from the sea for their annual moult and are soon to return to the Southern Ocean for their eight month long winter foraging migration. As some of the seals undertake this migration this year they will carry a miniaturised tracking and CTD unit to observe their foraging behaviour and features of the ocean around them. The device, called a CTD tag, will record where in the ocean the seal is, what it has been doing, and what the ocean temperature and water conductivity is along its path. This is the first year of a new long term monitoring program that will provide sustained observations of the Southern Ocean. Even after only one day at sea, the first seal is over 70 km from Macquarie Island and already diving to 700 m and providing diving and environmental profiles.
This data enables both biologists and oceanographers to learn from the seals to gain a much better understanding of how the environment influences the seals foraging behaviour and success directly in relation to differences in the ocean around them. At the same time it also provides data that can be used as input to ocean and climate models. The oceanographic data would otherwise be very expensive and extremely challenging, if not impossible, to collect. Therefore, this study provides a three fold benefit. First we learn about the at sea behaviour and success of an important predator in the Southern Ocean in relation to the environment it encounters. Second; this research provides invaluable oceanographic data, that in turn means that our oceanographic models will be more robust and third, this understanding can then be used to determine the big picture changes in the Southern Ocean and the influences they may have on the fragile ecosystem.