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    Comparison of NASC values calculated by swarm-based and grid-based acoustic data processing methods for Antarctic krill density estimation

    Solicitar acceso a documento de reunión
    Número de documento:
    SG-ASAM-18/04 Rev. 1
    X. Yu, X. Wang and X. Zhao
    Presentado por:
    Dr Xiaotao Yu (China)
    Aprobado por:
    Dr Xianyong Zhao (China)

    The one nautical mile integrated Nautical Area Scattering Coefficient (NASC) values of four surveys in 48.1 fishing area were calculated using both the swarm-based and conventional grid-based acoustic data processing methods. All parameter settings were consistent with the reports of SG-ASAM-2017 except that the dB difference window of Sv120 kHz-Sv38kHz is set 0 to 20 dB. And the two groups of results were compared by correlation, linear regression analysis and nonparametric significant difference tests (Kruskal-Wallis tests) to examine the validation of the developed swarm-based method for Antarctic krill density estimation. The comparisons suggest that the calculated NASC values of swarm-based and grid-based method show non-significant difference and significant linear relationship for all the four surveys. Therefore, it is concluded that the krill density estimated by swarm-based and grid-based method could be of good agreement.

    During the meeting, the subgroup suggested further analysis on swam-based approach and grid-based approach based on data in the paper. In accordance to the suggestions, further analyses were undertaken and the results were shown in Appendix A.