Proposal for marine protection of the Ross Sea

Antarctic orca
The great Ross Sea, the jewel of the vast Southern Ocean, is one of the last near-pristine ecosystems in the world. WDC is calling for these waters to be protected through the declaration of a large highly protected marine protected area or reserve. In October 2014, during a meeting in Hobart, Australia, the protection of this important region was once again blocked by China and Russia. It will be another year before CCAMLR (the Commission for the Conservation of Antarctic Marine Living Resources) meets again to decide the fate of this fragile ecosystem.

The great Ross Sea, lying some 4,000 km south of New Zealand and extending out from the ice edge of the Antarctic continent, is the jewel of the vast Southern Ocean. This remoteness has protected it from widespread pollution, invasive species and overfishing, making the Ross Sea the most pristine marine ecosystem left on the planet.

Plundered by whalers who took nearly all of its blue whales, the Ross Sea now supports numbers of orcas, minke, sei, sperm, Arnoux’s beaked and southern bottlenose whales and hourglass dolphins. There are also hundreds of thousands of penguins, seabirds and seals.

It has been called ‘the largest remaining, minimally-changed ecosystem on Earth’ by Antarctic penguin authority David Ainley.  In terms of measures of primary productivity and plankton standing stocks, the Ross Sea is the richest stretch of water of comparable size in the Southern Ocean and one of the last relatively untouched places on Earth where both top-down and bottom-up ecosystem processes can be observed and studied. Indeed, more than a quarter of the Southern Ocean’s phytoplankton production occurs in the Ross Sea, making it the most productive stretch of ocean south of the Polar Front.

The Ross Sea supports 95 fish species and more than a third of all Adélie penguins make their home in the Ross Sea, along with 30% of all Antarctic petrels and one quarter of all emperor penguins. Also found here are a genetically distinct population of orcas referred to as “ecotype-C” that may be specially adapted to feed on Antarctic toothfish, the top fish predator of the Ross Sea.

Antarctic toothfish fill a similar role to sharks in other ecosystems, but fishing interests from several countries are now removing the Antarctic toothfish from the ecosystem. Whereas most Antarctic fish species rarely get larger than 60 cm, Ross Sea toothfish can grow in-excess of two metres in length and more than 150 kg in mass. It is a long-lived species, slow to mature, and the current rate of fishing amounts to "mining" this fish for human consumption.

The Case for Protection

As perhaps the most intact marine ecosystem that is home to vast proportions of Southern Ocean wildlife, WDC supports the calls for the Ross Sea to be fully protected. WDC has joined forces with the Antarctic Ocean Alliance (AOA), a coalition of a large number of non-governmental organizations and scientists calling for the Ross Sea to be protected as part of a Southern Ocean network of no-take marine reserves and MPAs.

The Ross Sea offers us a unique natural laboratory to study the impacts of climate change free from the influence of human disturbance. Being the southernmost body of water on the planet, the Ross Sea will be the last part of the Southern Ocean with year-round sea ice according to the IPCC.

The most immediate threat to the Ross Sea is the recently developed Antarctic toothfish fishery. Industrial fishing vessels began operating in the Ross Sea in search of toothfish in the winter of 1996.

Fishery scientists who have been studying Ross Sea toothfish since the early 1970s have no longer been able to catch enough fish to continue their research in some areas of the Ross Sea. Studies indicate that industrial scale exploitation of large, deep-sea predatory fish have repeatedly proved unsustainable. The only way to ensure trophic cascades do not occur in the still pristine Ross Sea is to protect areas critical to the life-history stages of the Antarctic toothfish, including the Ross Sea shelf and slope and as such the Ross Sea has been identified by CCAMLR as a key region to be included in a representative network of MPAs.

Many of the Ross Sea’s top predators forage in this region of the shelf and slope, including Antarctic toothfish, orcas, minke whales, crabeater and Weddell seals, emperors and Adélie penguins and Antarctic and snow petrels.

Threats

Increased industrial fishing on the Antarctic toothfish (Dissostichus mawsoni), which is of critical importance to the Ross Sea ecosystem.

Japan’s infamous "scientific" catch of Antarctic minke whales (Balaenoptera bonaerensis). Thousands of whales have been killed in the Ross Sea by Japan since the moratorium on commercial whaling came into force. The data being gathered by Japan is obtainable by non-lethal methods, and the Japanese sell the meat commercially when the ships return to Japan.

Both Antarctic minke whales and orcas are classified as ‘Data Deficient’ on the IUCN Red List, while sei whales are ‘Endangered’. Sperm whales are rated as ‘Vulnerable’. This area was historically important for blue whales, which are now ‘Critically Endangered’ in the Antarctic. If blue whales are ever to make a comeback in the Antarctic, the Ross Sea’s productivity would be critically important for them.

Orcas (Orcinus orca), both ecotype-B and -C, are important to the Ross Sea, Antarctic ecosystem. The ecotype-C (often referred to as ‘Ross Sea orca’) ‘resident’ whales appear to feed principally on fish, including the large Antarctic toothfish. Recent observations have indicated that average group size appears to have decreased. This is consistent with a decrease in the catch-per-unit-effort of scientific fishing for toothfish in McMurdo Sound, and it has been suggested that the change in RS orca numbers in the southern Ross Sea is related to the impact of the industrial toothfish fishery. David Ainley and colleagues believe this means that the RS orcas have been displaced, in a scenario consistent with that of the Pacific coast of Canada, where numbers of resident orcas have decreased following the loss of large prey fish.

The Proposal for Protection

WDC joins with the AOA in recommending that CCAMLR establish a fully protected marine reserve of approximately 3.6 million square kilometers in the Ross Sea region as a first step to establishing a comprehensive network of MPAs and marine reserves around Antarctica.

You can find out more about the proposed Ross Sea Marine Protected area at: www.cetaceanhabitat.org and at www.asoc.org.