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    Models of larvae dispersion of Antarctic toothfish (Dissostichus mawsoni)

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    Document Number:
    WG-FSA-12/48
    Author(s):
    A. Dunn, G.J. Rickard, S.M. Hanchet and S.J. Parker (New Zealand)
    Submitted By:
    Sarah Mackey (CCAMLR Secretariat)
    Abstract

    Antarctic toothfish (Dissostichus mawsoni) have a circumpolar distribution, and have been found associated with bathymetric features shallower than 2250 m and typically deeper than 500 m from the Antarctic continent north to approximately 57° S. Efforts to understand early life history and stock structure in the Ross Sea have parallels for populations in other regions of the Antarctic, and hypotheses about how stock structure is maintained may apply to each population.

    We provide an update of the circumpolar models of larval dispersion for D. mawsoni developed by Hanchet et al. (2008) using the HiGEM circumpolar oceanographic model documented by Rickard et al. (2010). We used a finer resolution of simulated locations in the northern areas of Subarea 88.1 & 88.2 to further investigate the possible larval dispersal from spatially discrete spawning grounds in these Subareas. Further, we derive plausible spawning locations from Scientific Observer sampling of D. mawsoni in other ocean sectors to identify starting locations for modelling the potential egg and larval dispersal around Antarctica using the HadGEM (Rickard et al. 2010) oceanographic model. The results are currently too preliminary to make conclusions about possible stock structure within these sectors. Information on the depth of transport and the timing and velocity of any directed swimming will assist in improving these simulations.

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