Macquarie Island - Island Life 2/6 - Go Wild

Macquarie Island is a tiny fragment of land between Tasmania and Antarctica and one of few of islands in the Southern Ocean. Each Spring, thousands of sea birds and mammals converge on the island in order to leave the water and breed. This seasonal influx of life also makes Macquarie an oasis for biologists. With the creative application of technology, those scientists are gaining fascinating insight into the mysterious ocean-going lives of the island’s seasonal visitors.

The island’s natural history has been a magnet for scientists and for over 50 years Australia has operated a research station at the northern end of the island. The station is home to over 40 people over the summer and around 20 through winter. A wide variety of research is carried out on the island including biology, botany, auroral physics, meteorology and medical research.

Southern elephant seals are one of the longest monitored animals on the island. Elephant seals spend most of their lives at sea, but return to the same beaches each year to breed and moult.

While elephant seals are relatively well studied on land, their ocean going life is largely a mystery. To understand more about how elephant seals interact with their ocean environment, work from Macquarie island is tracking individual seals when they leave the island to feed and measuring how deeply they dive and which areas of the Southern Ocean they’re targeting.

What is known to date is that southern elephant seals are extraordinary ocean wonders. Capable of diving to over 1500 metres in depth, staying submerged for up to 2 hours and swimming thousands of kilometres. Yet despite being masters of their ocean world, the numbers of elephant seals on Macquarie Island has steadily decreased over the past forty years. The exact reasons behind this decline are unclear, however the answer probably lies in how they feed in the Southern Ocean.

Royal penguins are also being tracked to understand more about their feeding behaviour. How and where the birds feed, what they eat and how much. This data is then compared against how successfully the birds breed over seasons.

Each year the penguins return to Macquarie Island to find the same nest sites and generally the same partner. But the marine environment that they depend upon to feed can vary greatly with natural events such as El Niño and potentially with human induced changes such as global warming and fishing. By understanding how the birds are affected by natural variations can provide a valuable model for understanding how the birds will be affected by future human influenced changes.