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.