African Reserves

Study highlights need for Southern Ocean marine conservation areas

The largest research project ever undertaken by multiple nations, using seabird and mammal tracking data across the Southern Ocean, calls for the urgent creation of conservation areas.

The results of this international collaboration, published in Nature, aim to inform spatial management across the Southern Ocean, to recommend where Marine Protected Areas (MPAs) should be expanded or new MPAs created in areas of national jurisdiction as well as in the high seas where there is no there is no national jurisdiction. The objective is to maximize the conservation of biodiversity in ecologically significant areas.

Sub-adult Southern Elephant Seal with King Penguins at Kildakey Beach on Marion Island. Tracking data from both species was used in the study published in Nature. (Peter Pistorius)

The call was made in an article published in the prestigious international journal in 2020, titled Tracking of Marine Predators to Protect Southern Ocean Ecosystems.

The article reads: “Integrating over 4,000 tracks from 17 species of birds and mammals reveals AES [areas of ecological significance] around sub-Antarctic islands in the Atlantic and Indian Oceans and on the Antarctic continental shelf. Fishing pressure is disproportionately concentrated within the ESAs, and climate change over the next century is expected to put pressure on these areas, particularly around the Antarctic continent. Currently, 7.1% of the ocean south of 40°S is under formal protection.

One of the co-authors, Professor Pierre Pistorius, who heads the Large Marine Predators Research Unit at Nelson Mandela University, explains the background: “For many years we have been deploying instruments tracking devices for seabirds and marine mammals – small GPS units or satellite transmitters – attached with waterproof tape to their feathers, and easily removed, or with epoxy glue or darts on seals and cetaceans [whales, dolphins and porpoises]. For this large international study, we only integrated tracking data from species that have a distribution across the Southern Ocean region, such as wandering albatrosses, macaroni penguins and southern elephant seals.

“We studied the distribution at sea of ​​these marine predators because they are very good at locating areas of high productivity and rich in food for their survival. These areas are what we call Ecologically Significant Areas (ESAs). They are productive from the bottom of the food chain to the top, with nutrient enrichment stimulating phytoplankton growth activity, which leads to zooplankton biomass moving up the food chain.

Data reveal that the identification and protection of multiple ocean-scale ESAs by the multinational MPA expansion mechanism is urgently needed to mitigate the pressures of large-scale resource exploitation on ecosystems of the Southern Ocean.

A pair of wandering albatrosses at Marion Island. (Chris Oosthuizen)

“We started using this approach, of using monitoring data to identify habitats important for conservation, in 2015, when one of my postdoctoral students at Nelson Mandela University, Ryan Reisinger, co- main author of Nature article, focused on tracking data from the Prince Edward Islands that make up the subantarctic territory of South Africa,” says Pistorius. “We have collated all of the historical monitoring data from various South African researchers for these islands and through habitat modeling we have identified important habitat around these islands to feed into the government’s MPA expansion strategy. South African.

“This was then followed by the global multi-nation initiative, where we used seabird and mammal tracking data across the circumpolar Southern Ocean – across the Indian, Pacific and Atlantic oceans, in d “In other words, all water south of 40 degrees.” Reisinger led the analysis of all of this tracking data.

A male molting southern elephant seal with king penguins at Tripod Beach on Marion Island. (Peter Pistorius)

Ship-borne hydroacoustic surveys can be used to study fish and squid biomass distribution, but due to the massive expanse of the Southern Ocean, this becomes logistically and financially prohibitive. The use of marine predators as indicators of these biologically rich areas is now well recognized as a feasible alternative, with this information guiding marine spatial planning initiatives.

Compliance is a major issue that needs to be improved. “Our project is linked to the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR), which is responsible for managing waters south of 60 degrees,” says Pistorius.

“CCAMLR is well placed to recommend MPAs for multinational management, which would help enforce compliance. The information we gathered sent clear guidance to CCAMLR on the need for these MPAs to ensure the long-term sustainability of marine resources and to prevent overfishing and unsustainable activities.

“Another major challenge we face here is that climate change is having a huge impact on the ecosystems of the Southern Ocean. With changing climatic conditions, we are also seeing changes in the distribution of important habitats and these changes should ideally be taken into account in marine spatial planning initiatives.

“Beyond fishing and climate-related threats, the world is clearly still very hungry for oil reserves. The creation of protected areas provides some protection against seismic activity and oil extraction in biologically important areas of the Southern Ocean.