CCAMLR

As part of the CCAMLR Scheme of International Scientific Observation, observers on-board Krill (Euphausia superba) fishing vessels measure the length of individual Krill sampled from commercial catches. These extremely valuable data may be used to monitor the state of harvested Krill populations. For instance, investigating length frequency distributions (LFDs) and their change over time provides insight into the underlying population dynamics. Three main processes drive temporal changes in LFDs: growth, mortality and recruitment. Understanding how these processes interact is a prerequisite to the interpretation of any observed trend. To illustrate these interactions a simple mechanistic individual-based model of krill population dynamics was subjected to a sensitivity analysis. Starting from a base scenario of cyclical annual recruitment, plausible ranges of growth, mortality and recruitment rates were tested and their effects on two length-based recruitment indices (the monthly median length and proportion of individuals smaller than 40mm, F40) were investigated. Results indicate that the annual span (maximum minus minimum) of F40 would be the best index of annual recruitment among those tested, and, that length-based indices may be used to determine the timing of recruitment events. However, since the population size structure at a given time is the result of a mixture of several annual cohorts, using such indices to quantify the intensity of a given recruitment event would need to take into account the relative magnitude of previous recruitment events.

In recent years, CCAMLR member states undertook substantial efforts to designate marine protected areas (MPAs) in the Southern Ocean. While MPA planning for six domains is underway, for three domains CCAMLR member states were asked to take the lead in MPA planning. At the CCAMLR meeting in 2012, the Commission welcomed the offer of Germany to take the lead in developing a Weddell Sea MPA for consideration in 2014. Subsequently, the German Federal Ministry of Food, Agriculture and Consumer Protection tasked the Alfred Wegener Institute (AWI) to compile and analyse scientific data for identifying potential conservation areas and measures in the Weddell Sea. The work under this project started mid-April 2013. Here, in our first conceptual outline, we (i) present the principal target area of our evaluation study aiming at a Weddell Sea MPA, (ii) give a systematic overview of our preliminary data retrieval accompanied by an invitation to all experts from within and outside CCAMLR to contribute relevant information and data sets and (iii) set out the project timeline in detail, i. a. to highlight an international expert workshop on the planning of a Weddell Sea MPA in 2014.

A  preliminary characterisation of available fishing information regarding catches and effort in Divisions 58.4.4a, 58.4.4b, 58.4.3a and 58.4.3b is presented. Information analysed corresponds to fishing logbooks recorded in the exploratory fisheries carried out between July 2000 and March 2012. During this period, a total of 9 countries registered fishing operations in which 1811 sets were recorded (79.3\% 58.4.3; 20.7\% 58.4.4) accounting of 1605 tons of toothfish. Division 58.4.3b (Banzare Bank) accumulated the highest proportion of allocated effort in which a total of 948 sets (52\%) were performed. Catches of toothfish have declined since fishing season 2006 and total allowed catch assigned has not been completed in most of the recent fishing seasons. Soaking time showed high variability and no seasonal pattern was detected and spatial coverage of fishing operations showed a reduction across time. Baseline analysis presented in this report provides relevant information for the exploratory fisheries and also for future research and management plans.
 

WG-EMM has a broad agenda for discussions in 2013, including the following items related to feedback management: “review of spatial and temporal structure in the ecosystem in which the current Area 48 fishery operates” and “development of agreed decision-making mechanisms for the candidate feedback management approaches”. The British Antarctic Survey Ecosystems programme and its predecessors have been studying the structure and operation of this ecosystem for several decades. Some of this work has focused on the management and monitoring of this ecosystem. These programmes have therefore generated numerous publications relevant to the WG-EMM agenda. The current document lists selected relevant publications from 2009 to 2013, copies of which will be available from members of the UK delegation during the 2013 WG-EMM meeting.
 

Antarctic krill is an obligate cold water species, an increasingly important fishery resource and a major prey item for many fish, birds and mammals in the Southern Ocean. The fishery and the summer foraging sites of many of these predators are concentrated between 0° and 90°W. Parts of this sector have experienced recent localised sea surface warming of up to 0.2°C     per decade, and projections suggest that further widespread warming of 0.27° to 1.08°C will occur by the late 21st century. We used a statistical model linking Antarctic krill growth to temperature and chlorophyll concentration to assess the influence of projected warming on Antarctic krill habitat quality. The results divide the sector into two zones: A band around the Antarctic Circumpolar Current in which habitat quality is particularly vulnerable to warming; and a southern area which is relatively insensitive. Our analysis suggests that the direct effects of warming could reduce the area of growth habitat by up to 20%. The reduction in growth habitat within the range of predators, such as Antarctic fur seals, foraging from breeding sites on South Georgia could be up to 55%, and the habitat’s ability to support Antarctic krill biomass production within this range could be reduced by up to 68%. Sensitivity analysis suggests that a 50% change in summer chlorophyll concentration could have a more significant effect on Antarctic krill habitat than the direct effects of warming. A reduction in primary production could lead to further habitat degradation but even a 50% increase in chlorophyll would not completely negate the degradation of habitat available to predators. While there is considerable uncertainty in these projections, they provide strong and specific evidence that climate change poses a threat to Antarctic krill growth habitat and consequently to Southern Ocean biodiversity and ecosystem services.

As part of its long-term goal, ICED encourages the rescue and integration of existing data sets to enable investigation of long-term, large-scale ecosystem dynamics across the Southern Ocean. Historical data sets have a particular value in providing ‘baseline’ physical and biological data, against which we can assess current and future dynamics of ecosystems under scenarios of climate and anthropogenic-induced change. Such information can be used to underpin sustainable management strategies. We give an example of an historical data rescue project that is being conducted by ICED scientists at the British Antarctic Survey, centred on the first comprehensive oceanographic research campaign in the Southern Ocean, the Discovery Investigations (1925-1951). ICED is keen to work with CCAMLR to determine how best to make use of the resulting datasets and scientific outputs. ICED also sees great value in working alongside CCAMLR scientists to identify other relevant datasets that require rescue and integration to aid monitoring and management of Southern Ocean ecosystems. We invite data holders to supply summaries of relevant data sets which we will collate in an open access document. This document should assist the efforts of data holders and the wider community to raise awareness and develop strategies to make data available for analysis.
 

In late 2012 SCAR, BirdLife and BAS developed a successful proposal (to the UK Darwin Plus Fund) to build an integrated database that would facilitate the analysis of penguin tracking data. The database will have a web-based user interface that will allow data holders to submit data and attach a range of access levels; access may be granted only to the data holder, to a wider group, or to a general public domain. A penguin database (built along analogous lines and interoperable with the BirdLife Global Procellariiform Tracking Database) will allow spatial analyses to be undertaken that will help inform a variety of CCAMLR analyses, including work on the development of a variety of feedback management approaches for the krill fishery, and work on the spatial planning processes needed for identifying candidate CCAMLR MPAs.

Southern ocean processes are intimately linked to some of the most pressing challenges faced by society today: climate change, ocean acidification and the sustainable management of marine resources. To address these challenges we need to improve our understanding of the natural causes and consequences of Southern Ocean change. Sustained observations, which can only be large enough and maintained through international collaboration, will enable us to measure the baseline and future trends in the distribution and function of the ecosystem. The Southern Ocean Network of Acoustics (SONA) represents a group of scientific institutes and industrial partners who have united to measure an under-sampled component of the ecosystem – the mid-trophic level, to agree common standards and protocols for data collection and processing with a view to provide that data on an open access basis.