CCAMLR

The authors analyzed the spatial-temporal structure of standardized indices of catch per effort unit (CPUE)  of Antarctic krill fishery in the Area 48    in  relation to dynamic of ААО indices (Antarctic Oscillation Index) as one of the factors used in analysis of inter-annual and long-period fluctuations of hydrometeorological conditions at high latitudes of the southern hemisphere.  Standardization of CPUE values was calculated on the basis of generalized linear models method with mixed effects (GLMM). Analysis of the time-series of CPUE and AAO indices were carried out using the modern de-nosing data methods, including wavelet transform, Markov’s regression model to determine the fishery regime shifts and multivariable wavelets de-noising. The influence of climate variability was traced in the long-term dynamics of fleet operation including standardized indices of catch per effort unit (CPUE), monthly catches and catches per vessel day.  It was shown that the most important evidence of ongoing climate variability is the fishery regimes switching observed in long-term fishery in the Area 48. It was found that the most significant switching of fishery regime occurred in 2006-2011, when fishery had transferred to the state «high CPUE». This period is characterized by the highest values of CPUE and AAO indices for the whole observation period 1985-2011.  Analysis of krill fishery indices obtained with using different fishing technologies revealed that the “high CPUEs” regime is not associated with the changes in fishery technology and using the continuous fishing method, but is due to the influence of the current climatic changes.

A meso-scale zooplankton and krill net sampling survey was carried out in the north-western Weddell See and in Bransfield Strait/western Antarctic Peninsula during late January to early March 2013. The aim of the survey was to study the zooplankton composition and krill abundance and distribution in the outflow region of the Weddell Sea. Due to severe pack-ice conditions, more than half of the survey area was covered by ice during the summer season. Antarctic krill densities were found to be highest in the western Peninsula region and lower in ice-covered Weddell Sea waters. Overall krill density was below the longterm average of the area. New one-year-old recruits were scarce, the stock was dominated by two and three year old krill. Spawning occurred late and numbers of gravid females and larvae were low. Ice krill E. crystallorophias was abundant on the shelf of the north-western Weddell Sea. Thysanoessa macrura and salps Salpa thompsoni were far less abundant than the longterm average and were confined to the more northern, ice-free areas.

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.