CCAMLR

Acoustically based estimates of Antarctic krill (Euphausia superba) biomass, and net-based estimates of krill density and recruitment are recalculated for the years 1996 through 2011. Recent changes in the acoustic methodology and target strength models are the basis for the recalculation. The time series of acoustic biomass indicate that krill have varied by more than an order of magnitude over this time period. Current estimates for the South Shetland Islands region are 3.6, 1.9 and 1.35 million tons for the Elephant Island, West and South Areas, during leg 1. Recruitment estimated from net based data show that 2011 was a year of good recruitment, following two years of low recruitment. Krill biomass in the northern Gerlache Strait, an area of just over 1100 km2, exceeded 110 g m-2 which results in a biomass of more than 128 000 tons. Refining biomass estimates and estimates of recruitment will help to better inform CCAMLR about the status and trends of krill in Area 48.1 an area experiencing the most rapid climate change as well as population declines of major land-based predators.

Despite uncertainties about interactions between ecosystems and fisheries, the ability to adjust activity of the Antarctic krill fishery based on the state of krill-dependent predators is a recognized goal of the CCAMLR. We suggest that progress toward a feedback management approach can be made efficiently via the comparative approach. Specifically, changes due to an impact in one population can be assessed by measuring trends in the difference between the observed states of a “treatment” and a “control” population. As the states of these monitored populations change relative to each other, an impact in one population will cause the relative difference between them to change. Comparing trends in the difference between pre- and post-treatment states may provide information about the magnitude of impacts that are useful for a feedback management strategy. We use a simulation study to illustrate sensitivity to the choice of data and impact, and to suggest that useful comparisons can be made across space and across species. The results suggest that relatively minor changes in the rate of decline in treatment data or minor shifts in the mean of treatment data resulted in readily identifiable (probability ≥ 95%) differences in the relative behaviour of treatment and control populations over a short (5 yr) time horizon. Such sensitivity may prove useful for the detection of impacts in monitoring data and consequent management action.

The data of 18 expeditions fulfilled by AtlantNIRO during 1970-2000 in the central and eastern part of the Area 48 (Subareas 48.4 and 48.6) were summarized. Distribution of krill was analyzed with reference to the structure and dynamics of the water masses in the area of the Southern Sandwich Islands arc, the Bouveau Island, the Maude seamount, the southern part of the Lazarev Sea and up to the coastal zone of the Antarctic. It was demonstrated that in these areas in the frontal zone of the Weddell circulation and in the area of the Antarctic nearshore current the oceanographic conditions appeared favorable to formation of commercial krill aggregations, which might be attractive in biomass distribution to the fishing fleet operations during certain seasons. The Subareas 48.4 and 48.6 may become one of the probable directions of krill exploratory fishery in the Convention Area.

During the CCAMLR WG-EMM in July 2010, Aker Biomarine ASA offered to carry out a 5 day survey each year for the next five years in the CCAMLR statistical Subarea 48.2 using the Norwegian krill fishing vessel „Saga Sea‟. This report describes methodology, presents raw data and preliminary results from the first of these surveys, carried out in February 2011 near the South Orkney Islands

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. This paper describes the structure of the GIS database and provides example outputs. The utility of the GIS will be maximised by ensuring that it is kept up to date and easily accessible to stakeholders.

The Southern Ocean is a globally important marine region, providing a range of ecosystem services which support human life, health and well-being, including the provision of marine living resources, and the regulation of global climate and sea level. Assessing ecological processes in terms of the services they provide translates the complexity of the environment into functions which can be more readily understood, for example by policy-makers and non-scientists. Ecosystem-based management requires the consideration of a wide range of objectives, and the language and concepts of ecosystem services may help to provide a common currency for balancing these objectives. However, the importance of the Southern Ocean ecosystem is generally under-represented in assessments of ecosystem services at the global scale, reflecting the spatial separation of Southern Ocean ecosystem services and their beneficiaries. Equally the concept of ecosystem services is not generally used within the Antarctic Treaty System (ATS), creating a potential disconnect between global and regional policy. Nevertheless, decision making processes within the ATS are in many ways pre-adapted to deliver evidence-based policy which takes the current and future value of multiple ecosystem services into account. Also, much of the evidence gathering work which has been conducted to support decision making in the Antarctic context could relatively easily be adapted to fit an ecosystem services evaluation framework.
Here we provide a brief review of Southern Ocean ecosystem services, and outline preliminary work towards an assessment of their distribution, status and value. The benefits of assessing Southern Ocean ecosystem services in this way include (i) emphasising their global importance; (ii) facilitating comparisons of individual services across the ATS; (iii) facilitating consideration of the full suite of ecosystem services under the ATS; (iv) allowing comparability with global governance frameworks. This has particular relevance to the work of CCAMLR, given its responsibility for the maintenance and sustainable provision of living resource services from the Southern Ocean ecosystem, and the increasing need to communicate its role in ecosystem based management to a global audience of stakeholders.

In June 2010 the CCAMLR ASAM working group examined the acoustic methodology applied to the CCAMLR 2000 synoptic survey data to generate a quality checked krill biomass for area 48 following the acoustic protocol identified in ASAM 2009. The total biomass of krill in the Scotia Sea was estimated from acoustic and net data collected during the international multi-ship krill biomass in the Scotia Sea in 2000 to be 60.3 million metric tonnes. This report aims to document the parameters utilised during the assessment and include additional information of krill density by strata and transect published for the original methodology, but omitted from the ASAM2010 report (SC-CAMLR-XXIX, Annex 5).

 This paper provides a brief status report on the ongoing analysis of KRILLBASE.

One of the main issues in the management of the krill fishery is finding a spatial subdivision of catches that allows CCAMLR to achieve its objectives for both the fishery and the ecosystem. This requires a framework of spatial areas over which catches can be subdivided. WG-EMM has devised an initial framework of small scale management units (SSMUs) in subareas 48.1 to 48.4 based on the spatial structure of the ecosystem. This framework is hierarchical. It recognises a distinction between coastal (shelf and shelf-break) areas and oceanic areas. WG-EMM devised thirteen coastal SSMUs with an average area of 34,690 km2, separating discrete concentrations of land-based predator colonies. WG-EMM also devised just four SSMUs, with an average area of 758,809 km2, to cover the remaining 87% of the four subareas. The oceanic SSMUs are the location of 72% of the estimated krill biomass, 61% of the estimated consumption of krill by predators and 10% of the cumulative total fishery catch in the three subareas (48.1 to 48.3) where the fishery operates.
There is ample evidence of structure in oceanic areas from both ecological and oceanographic studies, and from the concentration of krill catches in limited parts of the oceanic SSMUs. A more detailed application of knowledge about ecological structure is likely to allow more, finer-scale SSMUs to be devised for oceanic areas. This would: (i) allow a greater range of options for the subdivision of catches; (ii) afford oceanic predators a greater level of protection from localised fishery impacts; and (iii) allow more realistic evaluation of management strategies in terms of consequences for both the fishery and the ecosystem.
Krill distribution during the CCAMLR 2000 synoptic survey is an indicator of ecosystem structure. Relationships between krill distribution and physical environmental characteristics could be used to identify units of coherent structure in oceanic areas. British Antarctic Survey scientists are currently conducting this analysis. Because the synoptic survey only provides a single snapshot of structure it will be necessary to further investigate the consistency in this structure over intra- and inter- annual timescales by (a) testing for such consistency in longer time series of data on physical characteristics which have spatial relationships with the distribution of krill and (b) directed survey or fishing effort to test hypotheses about where concentrations of krill are likely to occur in oceanic areas. The fact that the physical influences on this structure are often dynamic (e.g. frontal systems), presents an additional challenge. Nonetheless, it is important to address the disparity between the scales of coastal and oceanic SSMUs to provide CCAMLR with the tools necessary to manage these habitats in a consistent way.

The Generalised Yield Model was used to estimate fishing mortality and spawning stock biomass reference points for the krill fishery in CCAMLR Area 48 consistent with the catch trigger level of 620,000 tonnes. Projections were run with various increased levels of recruitment variability to analyse the sensitivity of the estimates of the reference points to recruitment variability.
The estimates of F and SSB reference points for the krill stock in Area 48 consistent with the catch trigger level are 0.0159 (95 % CIs: 0.00750 – 0.0357) and 97.7 % SSB0 (80 % CIs: 71.6 – 135 %) respectively. In comparison, the F and SSB reference points for the precautionary catch limit of 5.61 million tonnes are 0.186 (95 % CIs: 0.0762 – 0.630) and 75.0 % (47.9 – 113 %) respectively.
The probability of stock depletion increases substantially with increased recruitment variability, though in absolute terms remains negligible. The uncertainty surrounding median estimates of F and SSB reference points for the catch trigger level increases with increased variability in recruitment, though the median estimates are unaffected.

The model terminated prematurely with a 40% increase in recruitment proportion SD. It is likely that this is due to a design feature of the Generalised Yield Model in place to prevent projections from running with potentially significant bias in projected recruitment resulting from poor parameterisation of the beta function.