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    The variability of egg and larval transport of Antarctic toothfish under the extreme SAM event in the East Antarctic region (Division 58.4.1 and 58.4.2)

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    Document Number:
    WG-FSA-2021/37
    Author(s):
    M. Mori, K. Mizobata, K. Kusahara, T. Ichii and T. Okuda
    Submitted By:
    Dr Mao Mori (Japan)
    Approved By:
    Dr Taro Ichii (Japan)
    Abstract

    This paper examined eggs and larval transport pathways of Antarctic Toothfish under extreme Southern Annual Mode (SAM) events in the continental slope-shelf regions of East Antarctica using a particle tracking model. Ocean currents datasets were calculated using a coupled ocean-sea ice-shelf model output “COCO.” Model simulation results indicated transport pathways of particles released from the east side slopes in the East Antarctic regions were different between the positive and negative SAM phases. While the Antarctic slope current (ASC) generally prevailed southwestward transports of particles from slopes to inner shelves regardless of release regions under both extreme SAM events, particles released from the northeast slopes were transported offshore by the Antarctic Circumpolar Current (ACC) or inner shelves by the combination of ACC and local recirculation system. The result suggests extreme SAM events caused the change in the transport of egg and larvae in the east slopes of the East Antarctic region.