Preliminary results of modelling egg and larval transport of Antarctic Toothfish (Dissostichus mawsoni) in the Weddell Sea region

This study presents preliminary results of modelling the transport of eggs and larvae of Antarctic Toothfish (Dissostichus mawsoni) in the Weddell Sea region using ocean and sea ice reanalysis data. Virtual particles were released from identified spawning grounds and tracked for three years under two surface advection schemes: ocean-only (OAS) and ice-ocean (IOAS). The results show that sea ice significantly influences transport speed and direction, particularly in continental slope regions. Transport success to nursery grounds varied by release location, timing, and advection scheme. Subareas 48.1 and 48.2 showed consistently high success rates, while Subarea 48.4 and offshore banks such as Elan and Banzare exhibited low recruitment. Continental slope regions (Divisions 58.4.1, 58.4.2, and Subarea 48.6) demonstrated high success under OAS, though IOAS often reduced success due to altered transport pathways. These findings highlight the importance of incorporating vertical migration and linking climate variability (e.g., SAM, ENSO) into future models to better understand recruitment dynamics and support fisheries management in Subarea 48.6.