Climate and fisheries take a toll on Antarctic krill

But climate and fishing stresses are taking their toll on Antarctic krill: rising ocean temperatures and dwindling sea ice are changing its habitat, especially around the Antarctic Peninsula. About 70 per cent of krill live in this sector, so many predators are also found here and there is also strong fishing pressure. Around the Antarctic Peninsula, in recent years the catch limit has been reached earlier and earlier in the year and, as a result, pressure has increased on the stocks around the South Orkney Islands further east. In these two parts of the Southern Ocean, krill catches are now more spatially and temporally concentrated than ever before.

Prof. Dr Bettina Meyer, biologist at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research and Dr So Kawaguchi, principal research scientist at the Australian Antarctic Division in Tasmania (Australia) ask in the Science editorial whether catch limits are set and distributed in the right temporal and spatial dimension, now and in the future. To answer this question, further research is needed to better understand krill biology and the interaction between krill and the species that depend on them. It is also unclear how these interactions are affected by climate change.

According to Bettina Meyer and So Kawaguchi, research can only answer these questions if it cooperates with the fishing industry itself, because unlike research vessels, the new generation of krill fishers is in operation almost all year round. Collaboration can enable regular scientific krill sampling in the data-poor Australian autumn and winter to fill knowledge gaps.

Both say: “It is time for the international community - from federal agencies to non-governmental organisations to industry - to support this research direction.” They are advisors to their countries in the CCAMLR for the assessment of krill stocks. New strategies for krill management and exploitation are currently being developed, including spatial and seasonal limits on Antarctic Peninsula catches to ensure the balance of the Southern Ocean ecosystem.

In the upcoming CCAMLR meeting (24 October to 4 November), the member states will also deal with the establishment of Marine Protected Areas (MPAs) in the Southern Ocean, among many other topics. In 2016, the European Union submitted a proposal for an MPA in the Weddell Sea, which was lead-managed by AWI researchers. The proposal is now supported by 18 of the 26 CCAMLR member states, but the required approval of all CCAMLR member states has so far prevented the establishment.