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    Two scales of distribution and biomass of Antarctic krill (Euphausia superba) in the eastern sector of the CCAMLR Division 58.4.2 (55°E to 80°E)

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    Номер документа:
    M.J. Cox, G. Macaulay, M.J. Brasier, A. Burns, O.J. Johnson, R. King, D. Maschette, J. Melvin, A.J.R. Smith, C.K. Weldrick, S. Wotherspoon and S. Kawaguchi
    Представлено (имя):
    Dr Martin Cox (Австралия)
    Утверждено (имя):
    Dr Philippe Ziegler (Австралия)
    Пункт(ы) повестки дня
    PLOS ONE, 17(8): e0271078 (2022), doi: https://doi.org/10.1371/journal.pone.0271078

    Regular monitoring is an important component of the successful management of pelagic animals of interest to commercial fisheries. Here we provide a biomass estimate for Antarctic krill (Euphausia superba) in the eastern sector of the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) Division 58.4.2 (55 ̊E to 80 ̊E; area = 775,732 km2) using data collected during an acoustic-trawl survey carried out in February and March 2021. Using acoustic data collected in day-time and trawl data, areal biomass density was estimated as 8.3 gm-2 giving a total areal krill biomass of 6.48 million tonnes, with a 28.9% coefficient of variation (CV). The inaccessibility of the East Antarctic makes fisheries-independent surveys of Antarctic krill expensive and time consuming, so we also assessed the efficacy of extrapolating smaller surveys to a wider area. During the large-scale survey a smaller scale survey (centre coordinates -66.28 ̊S 63.35 ̊E, area = 4,902
    km2) was conducted. We examine how representative krill densities from the small-scale (Mawson box) survey were over a latitudinal range by comparing krill densities from the large-scale survey split into latitudinal bands. We found the small scale survey provided a good representation of the statistical distribution of krill densities within its latitudinal band
    (KS-test, D = 0.048, p-value = 0.98), as well as mean density (t-test p-value = 0.44), but not outside of the band. We recommend further in situ testing of this approach.