It’s no secret that climate change, overfishing and pollution are changing the world’s oceans and that certain key areas need to be protected. But identifying these areas is difficult, especially in the most remote waters on Earth.
Scientists working in the icy Southern Ocean circling Antarctica came up with a unique solution to this problem.
Working together over the past two years, more than 70 scientists involved in Southern Ocean research — including South Africans — gathered and shared electronic tracking data for 17 species of seabirds and marine mammals. The study was based on the understanding that marine predators go where the food is — if several predator species are going to the same areas, it’s likely to be an area of ecological significance.
“Predators are very good at identifying and targeting productive areas. If whales, seals and penguins are all going to the same area, that’s where you’ll find a high abundance and diversity of species,” said Nelson Mandela University’s Pierre Pistorius, who heads up a South African National Antarctic Programme project tracking marine predators at Marion Island.
Whales, dolphins, seals, penguins, albatrosses and other species were tracked using the global positioning system and satellite transmitters attached to the animals’ bodies, allowing scientists to see exactly where they travel and spend their time foraging at sea.
The scientists gathered more than 4 000 individual tracks, and published their findings in the journal Nature in March.
“By tracking multiple species and doing some pretty complicated modelling [which included predicting movements from colonies where no animals were tracked], we were able to identify ecologically and biologically important habitats across the entire Southern Ocean, which will allow us to make very strong recommendations for their spatial protection,” said Pistorius.
“Many of the species we tracked are threatened, so it’s vital that we protect their foraging grounds.”
The areas identified as “areas of ecologically significance” are scattered around the sub-Antarctic islands in the Indian and Atlantic Oceans, and over the Antarctic continental shelf.
The study found that some Marine Protected Areas were already within these areas, but that additional MPAs are needed.
“We need to be aware that the impact of rapid climate change, which includes melting sea-ice and changes in sea temperatures and wind speeds, will likely shift these areas.
“It’s important that we keep monitoring the physical and biological properties of the Southern Ocean so we can manage MPAs in a dynamic way. For instance, we may need to be flexible with MPA boundaries.”
Twelve Antarctic research programmes contributed to the study, which was supported by the Scientific Committee for Antarctic Research, the Centre for the Analysis and Synthesis of Biodiversity in France and the World Wildlife Fund-United Kingdom.
In South Africa, the study was supported by the National Research Foundation and the department of environment, forestry and fisheries, and included participation from the universities of Cape Town and Pretoria.
Pistorius said collaborative projects such as this one were key to addressing global problems.
“There’s an urgent need to come up with solutions to minimise biodiversity loss, and it’s much more powerful working on a global scale than each country working independently.”