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    Are krill recruitment indices from meso-scale survey representative for larger areas?

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    Номер документа:
    V. Siegel (Germany), R.M. Ross and L.B. Quetin (USA)
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    The present contribution uses data from German surveys in the 1980’ies and the US LTER programme which continuously collected krill demography data since 1993 during the austral summer season in the upstream area of the Elephant Island mesoscale survey. The intention was to compare the recruitment indices derived from these two mesoscale surveys and analyse whether results from mesoscale surveys are representative for a wider region Generally the proportional recruitment indices for one (R1) and two-year old (R2) krill differ substantially between years. However, results were in conformity with the results from other scientific surveys. Recruitment indices showed a significant correlation for age-one-old krill between scientific surveys from the northern Bellingshausen Sea, the Elephant Island area and South Georgia. The correlation becomes weaker for R2 recruitment indices. No correlation was detectable between the krill recruitment of Atlantic and Indian Ocean survey sites. Problems of single-year outliers from Elephant Island are discussed as well as the problem of ‘undersized’ length classes of the age-one-group which occur in the samples of some years.