CCAMLR

The management of Antarctic krill and conservation of its predators requires understanding about the compound effects of changing habitats, ecosystem interactions, and fishing practices. For Antarctic pack-ice seals, a main group of krill predators, we report the spatial density and krill consumption in the West Antarctic Peninsula (WAP)-western Weddell Sea area, the main fishery region; and we consider long-term changes in suitable pack-ice habitat, increased fishing pressure and potential krill declines consequent on climate change. We find that the WAP has the highest known density of pack-ice seals and in the entire area, over 3 million crabeater seals can consume over 12 million tonnes of krill, approximately 17% of the krill standing stock; this highlights their extreme trophic pressure and dependence on krill. High seal densities where found in the small-scale fishery management areas of the WAP, where suitable seal habitat has declined between 21 and 28% over a 30 year period; krill density has potentially declined, and fishing has increased rapidly. The highest seal density was found in the Marguerite Bay area, a critical source of krill for the Antarctic Peninsula and elsewhere. This area has the highest seal impact on an already highly variable krill biomass, sea-ice loss of 66% has already occurred, and it could be an area of expansion for the fishery in the future. Uncertainty in krill and seal stock trends and in their environmental drivers calls for a precautionary management approach, in the absence of data to support a management based on specific conservation objectives for pack-ice seals.

An international effort is underway to establish a representative system of marine protected areas (MPAs) in the Southern Ocean to help provide for the long-term conservation of marine biodiversity in the region. Critical to this undertaking is understanding the distribution of benthic assemblages. Our aim is to identify the areas where benthic marine assemblages are likely to differ in the Southern Ocean including near-shore Antarctica.  We achieve this by using a hierarchical spatial classification of ecoregions, bathomes and environmental types. Ecoregions are defined according to available data on biogeographic patterns and environmental drivers on dispersal. Bathomes are identified according to depth strata defined by known species distributions. Environmental types are uniquely classified according to the geomorphic features found within the bathomes in each ecoregion.  We identified 23 ecoregions and nine bathomes. From a set of 30 types of geomorphic features of the seabed, 846 unique environmental types were classified for the Southern Ocean. We applied the environmental types as surrogates of different assemblages of biodiversity to assess the representativeness of MPAs. We found that for existing MPAs no ecoregion has their full range of environmental types represented and 12 ecoregions have no MPAs. Current MPA planning processes, if implemented, will substantially increase the representation of environmental types particularly within 7 ecoregions. To meet internationally agreed conservation goals, additional MPAs will be needed. To assist with this process, we identified 119 locations with spatially restricted environmental types, which should be considered for inclusion in future MPAs.

This paper presents results from two analyses that have been undertaken as part of Action 12 of the CHARM3 project, which focuses on spatial conservation planning in the English Channel. The first analysis investigates the use of species area curves for setting marine habitat targets and shows this approach is sensitive to sample size and the type of species richness estimator. Thus, there is a need for developing approaches that account for differences in sampling effort to ensure that targets are objective and scientifically defensible. The second analysis combines the Marxan and MinPatch conservation planning software packages to identify networks of MPAs that meet targets, minimise impacts on fishing and meet spatial constraints on the minimum MPA size and spacing. This work is ongoing so we present initial results that show how including additional constraints on MPA size produces a much less fragmented MPA network.

This paper is submitted for background information.  Marine Protected Areas (MPAs) are an important tool for biodiversity protection and marine conservation programmes globally. Although most MPAs have been established relatively recently compared to protected areas on land, there is considerable expertise on their identification, establishment, and management.  A global review of MPA management techniques, including case studies from the Antarctic and elsewhere, was undertaken in 2010 and highlighted the variety of possible ways to help achieve the objectives of MPAs.  The main tools which are relevant to managing MPAs in the area covered by the Antarctic Treaty and by CCAMLR are described in this “toolbox”.  Some of these management techniques have been adapted from terrestrial situations while others are novel and are unique to the marine environment.  The tools are presented as a range of approaches and options which could be considered, either individually or in combination, depending on what is most likely to help achieve the objectives of specific MPAs or MPA networks or systems.

We have developed a Geographic Information System (GIS) and accompanying metadata to store and deliver data on CCAMLR’s management units and spatially resolved conservation measures. The GIS facilitates easy mapping of CCAMLR’s spatial management framework and associated conservation measures, and standardises this information in terms of projection and coastline position. Access to spatially derived parameters through the database may be useful in the design and implementation of protected areas as part of the development of a representative system of Antarctic marine protected areas (MPAs), for example by allowing accurate calculation of existing management areas, and management area specific statistics including proportions of areas with particular characteristics. We present database outputs including the location and extent of existing spatial management, the distribution of pelagic bioregions across spatial management units, the proportion of bioregion areas open to fishing, and the proportion of bioregion areas protected by MPAs. The database also provides a central repository for information on the location and status of designated MPAs, which will be a key requirement for the effective development and maintenance of a representative system of Antarctic MPAs.

The development of a representative system of Antarctic marine protected areas (MPAs) will require up to date information on the location, conservation aims and current status of protected areas designated within the Convention Area. As at August 2011, there is one designated MPA managed by CCAMLR. In addition, the ATCM has designated 6 exclusively marine Antarctic Specially Protected Areas (ASPAs), 4 ASPAs with both marine and terrestrial components, and 3 Antarctic Specially Managed Areas (ASMAs) with both marine and terrestrial components (all located south of 60°S). A further 3 MPAs have so far been formally declared in those areas within the CCAMLR Convention Area that are managed under national jurisdictions. The geographic distribution and range of values being protected within these areas is currently limited and further areas will need to be designated in order to achieve a more representative system. The information compiled here provides a baseline against which additional proposed areas can be considered, and the future development of a representative system can be evaluated.

 Regional climate change is now known to be well established in the Antarctic; however, the implications for biological systems remain poorly understood. Investigating how marine species respond to climate change is potentially best carried out in regions and with species that have been little changed by human activities, particularly by the impacts (either direct or indirect) of marine harvesting. If CCAMLR is to embrace the wider implications of climate change in the context of ecosystem based management, it must understand how the Southern Ocean marine ecosystem will react to climate change, both in the presence of and absence of harvesting. We therefore recommend that locations currently covered by seasonal sea ice (as of 2011) could be considered for creation as restricted use Marine Protected Areas, and that the boundaries of such areas would henceforth remain fixed even though the average position of the ice edge may move further south in future years. Where implemented, these restrictions should remain in force until accumulated scientific evidence shows that krill population processes within these previously ice covered regions, retain the capacity to produce a sustainable harvest, taking into account the need to maintain ecological relationships including for dependent species.

Regional climate change is now known to be well established in the Antarctic, particularly in the Antarctic Peninsula region. One of the most evident signs of climate change has been ice shelf collapse; overall, 87% of the Peninsula’s glaciers have retreated in recent decades. Ice shelf collapse will lead to new marine habitats and to biological colonisation. Colonisation of these habitats may simply include species from areas that are immediately adjacent to the collapsed ice shelf; however, other complex processes may also take place as warmer waters may create opportunities for species to return that were last present during the last interglacial, a warmer period than at present. In addition, altered ecosystem dynamics may also allow new alien species to invade as ocean warming potentially removes physiological barriers that have previously led to the isolation of the Antarctic benthos. Given the complexity of the possible interactions and the need to study these in the absence of any other human induced perturbation we recommend that locations under existing ice shelves (as at 2010) should be created as no take Marine Protected Areas, and that the boundaries of these areas should henceforth remain fixed, even if the ice shelves recede or collapse in the future.