In recent decades, the fishery for Antarctic krill (Euphausia superba) has become increasingly concentrated around the Antarctic Peninsula, one of the fastest-warming places on Earth. Fishing and climate change combined may be working in tandem to cause a decline in populations of krill, a critical forage species in the region.
Commercial fishing grounds overlap significantly with foraging ranges for land-based predators, such as penguins. Declines of krill, especially in localized areas, could create a ripple effect throughout the Antarctic food web, causing imbalances in key predator-prey relationships. In the Antarctic Peninsula and Scotia Sea region, for example, breeding colonies of Adélie and chinstrap penguins, whose diets rely on up to 98 percent krill, have declined by half since the mid-1970s.
International ecosystem scientists gathered in Bologna, Italy, July 4-15, 2016, for the 16th meeting of the Commission for the Conservation of Antarctic Marine Living Resources’ (CCAMLR) Working Group on Ecosystem Monitoring and Management (WG-EMM). CCAMLR is a 25-member international body that sets policy, through a consensus-based decision process, for fishing and other resource use in the Southern Ocean.
The meeting featured discussion on whether to increase observer coverage on krill fishing vessels, how to fill science data gaps to develop an ecosystem-based management system for the krill fishery, and whether to renew a conservation measure for krill catch. CCAMLR members will make a decision on that measure at the next full Commission meeting in October.
Renewing critical Conservation Measure 51-07
To ease the impact of concentrated krill fishing on predator species, such as penguins, CCAMLR in 2009 split the annual precautionary krill catch limit of 620,000 metric tons among four regions off the Antarctic Peninsula, setting limits on the percentage of that catch for each subarea. The goal of that policy, Conservation Measure 51-07 (CM 51-07), is to avoid over depletion of krill populations from each subarea, particularly in coastal areas where land-based predators could suffer disproportionately.
Scientists with the ecosystem working group have recommended that maintaining those subarea catch limits would be the best way to achieve CCAMLR’s ecosystem conservation objectives, stating that there is no scientific basis for letting CM 51-07 lapse. Renewing this measure is particularly important as scientists work to develop an overall ecosystem-based management system for krill. Stopping CM 51-07 at this time would mean that fishing effort could become more concentrated in some of the most sensitive parts of CCAMLR Area 48, particularly in the Bransfield Strait (located in Subarea 48.1).
Advancing the science needed for ecosystem-based management
WG-EMM scientists also discussed development of an adaptive, big-picture approach to krill management, which is often called ecosystem-based management. Within CCAMLR, this is known as feedback management (FBM). It relies on monitoring important features of the ecosystem, such as populations of predator species and availability of prey, to enable fishery managers to increase or decrease catch limits in small-scale areas based on the overall health of the ecosystem.
To validate and eventually implement FBM, CCAMLR needs to gather new data, including an up-to-date estimate of krill biomass and distribution. The Commission also must standardize krill catch data to gain an accurate understanding of how much krill commercial fishers are catching, and mandate that all fishing vessels have scientific observer coverage. That collected data then will help CCAMLR better understand krill population trends.
In addition, scientists have discussed updating the CCAMLR Ecosystem Monitoring Program (CEMP), which provides indicators of how predator populations are responding to fishing and environmental change, and refining ecosystem models that can be used to evaluate catch limits in small-scale areas by testing how predators respond to those same factors.
Looking ahead to the full Commission session
CCAMLR delegates are meeting this October in Hobart, Australia. In making decisions at that session, Commissioners are obligated to take full account of the recommendations and advice of the WG-EMM Scientific Committee meeting. To ensure that science-based, precautionary policies are guiding krill fishing in the Southern Ocean, CCAMLR should heed the scientific advice and renew CM 51-07 until feedback management is in place. If CM 51-07 is renewed but amended, the Commission should prioritize predator needs—for example, by creating seasonal precautionary no-take zones around predator colonies, especially during the breeding season. In addition, CCAMLR should fill data gaps that are holding back implementation of feedback management and establish a timeline to achieve 100 percent observer coverage across all vessels in the krill fishery by 2018.
For additional details about the CCAMLR Working Group on Ecosystem Monitoring and Management, including reports from past meetings, visit https://www.ccamlr.org/meetings/19.
Andrea Kavanagh directs The Pew Charitable Trusts’ global penguin conservation work.