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    A study on calibration for commercial echosounder using bottom backscattering strength in Antarctic

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    Document Number:
    SG-ASAM-17/P01
    Author(s):
    S.-G. Choi, H. Lee, K. Lee and J. Lee
    Submitted By:
    Dr Seok-Gwan Choi (Korea, Republic of)
    Approved By:
    Dr Seok-Gwan Choi (Korea, Republic of)
    Agenda Item(s)
    SG-ASAM-17 - 2 - Protocols for the collection and analysis of krill acoustic data from fishing vessels, with emphasis on Simrad echosounders (EK60, ES60/70)
    Publication:
    Fisheries Technology in Korea
    Abstract

    In this study, we calibrated a commercial echosounder (ES70) installed on a krill fishing vessel to use it in estimating biomass of Antarctic krill (Euphausia superba). The method of calibration was to analyze the difference between the bottom backscattering strength of the commercial echosounder (i.e. ES70) and the scientific echosounder (i.e. EK60) at some transects designated by CCAMLR. 38kHz and 120kHz were used for the calibration, and krill swarm signals, obtained from multi frequencies, was examined to verify the calibration result. The analysis result confirmed the possibility of calibration by bottom backscattering strength, since the proportion of krill swarm signals within 2 dB < SV120kHz‒38 kHz < 12 dB (i.e. a common ΔMVBS range of 38kHz and 120kHz to be an indicative of Antarctic krill) over the total acoustic signals were 26.95% and 92.04%, respectively before and after the calibration.