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Sustainable management of krill resources in the Southern Ocean

Sustainable management of krill science briefingDownload PDF version

Krill, a tiny shrimp-like crustacean, is a food source for whales, penguins, other seabirds and seals. Rich in oil and other nutrients this marine animal is in demand by commercial fisheries for feeding farmed fish, nutritional supplements for humans and other products. As markets for these products grow it is important to ensure that krill fish stocks are preserved and managed sustainably for native species and for human needs. Long-term ecosystem research by British Antarctic Survey underpins the conservation and management of these species.

What research are BAS scientists doing on krill fishing in the Southern Ocean?

BAS scientists have a long history of working with the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) and have been very active in supplying scientific evidence to support many of the policy and management decisions made by CCAMLR about how to regulate Southern Ocean fisheries, including the krill fishery close to the Antarctic Peninsula and at South Georgia, a UK Overseas Territory. CCAMLR first met in 1982 and now comprises 25 Member states. It uses an ecosystem-based management framework.

What is a sustainable level of fishing?

CCAMLR is in the process of designing a new management system for the krill fishery which aspires to spatially subdivide the krill catch so that it does not have adverse impacts upon the marine predators that feed upon krill. This is a long term project that requires collaboration and agreement between scientists from many nations, commercial fishers, fishery managers and Non-Governmental Organisations. Until the new system is ready, an interim catch limit has been set in place. This limit, 620,000 tonnes, is equivalent to approximately 1% of the estimated krill biomass in the southwest Atlantic, the location where the commercial fishery currently operates. The fishery cannot expand beyond this highly precautionary limit until the new management system is agreed.

Do BAS scientists receive funding from any of the fisheries companies?

BAS scientists do not receive funding from any commercial krill fishing company. However, BAS scientists do collaborate with fishing companies in order to understand how the fishery operates. This collaboration has helped increase our understanding about the impacts of fishing on the Antarctic marine ecosystem. One of the krill fishing vessels that we collaborate with is certified by the Marine Stewardship Council. In addition to its long-term biological research programme at Bird Island Research Station BAS scientists conduct commissioned research for the Government of South Georgia and the South Sandwich Islands (GSGSSI) at King Edward Point applied fisheries laboratory. This research provides the sound scientific advice that is necessary to inform decision-making for the sustainable management of commercial fisheries around the island.

What level of protection is there over the level of krill fishing at South Georgia?

The waters around South Georgia and the South Sandwich Islands (SGSSI) are subject to the provisions of the CCAMLR Convention. Therefore, the Government of SGSSI manages fisheries that are also subject to Conservation Measures agreed through CCAMLR. Historically, GSGSSI has frequently imposed more stringent management provisions than CCAMLR. For example, in February 2012 GSGSSI implemented a large, sustainably managed, Marine Protected Area around South Georgia and the South Sandwich Islands covering the territorial waters north of 60°South, stretching from the coast out to a distance of 200nm. Following a stakeholder consultation new provisions for the South Georgia Marine Protected Area were announced in January 2013.

Do krill stocks remain constant?

BAS has a long history of research into krill and its dependent species. It is worth noting that the abundance of krill is known to vary naturally, and in some years krill can be scarce. Scientific evidence shows that populations of some krill predators can also vary in response to these natural fluctuations. In addition, other evidence shows that some predators, and possibly krill itself, are undergoing longer term changes; however, the reasons underpinning these changes are not completely understood and are the focus of an ongoing active research programme, both within BAS and internationally. What is certain, however, is that Antarctic fur seal populations at South Georgia are now very extensive, having recovered from past exploitation. Similarly, some species of whale that are believed to feed in the South Georgia Marine Protected Area are also finally showing signs of recovery. The current and ongoing recovery of these species suggests that krill is not limiting in most years. In order to protect krill predators and promote the recovery of depleted populations of some krill predators, the GSGSSI has implemented a temporal closure of the krill fishery. This restricts krill fishing to the winter months, so preventing direct competition between the fishery and krill predators at a time when they are rearing their offspring. During the winter when the fishery is allowed to operate many krill-eating predators have left the South Georgia ecosystem and have migrated to other waters.

What effect is climate change having on krill fisheries?

A recent but very important concern in the Antarctic is climate change. This has the potential to significantly alter marine ecosystems, through changes in temperature, ocean acidification, and changes in sea ice cover. CCAMLR is already very concerned about the threat of climate change to fisheries, as is the GSGSSI. Managing fisheries into the future will require very careful consideration of these effects and may require new restrictions on fisheries.

Sustainable fishing

The Commission for the Conservation of Antarctic Marine Living Resources’ (CCAMLR) ecosystem-based management framework requires:

  • Maintenance of harvested populations at healthy levels, and recovery of depleted populations to those levels.
  • Maintenance of healthy ecosystems, characterised by the ecological relationships between harvested populations and dependent species.
  • Prevention of changes to the ecosystem which are not potentially reversible within three decades.

This is consistent with various definitions of sustainability, including the Marine Stewardship Council’s Principles and Criteria for Sustainable Fishing, and the Scientific Consensus Statement on Marine Ecosystem-Based Management.