Movements of tagged Antarctic toothfish (Dissostichus mawsoni) in Subarea 48.6 in relation to stock structure hypotheses

We examined movements of tagged Antarctic toothfish (Dissostichus mawsoni) for subarea 48.6 in relation to life history hypotheses. Most of long-distance movements occurred in westward direction along continental shelf, which may be consistent with the single Atlantic population hypothesis (Söffker et al., 2018). Meanwhile, no migrations of tagged fish between northern seamounts (research blocks 48.6_2 and 48.6_3) and southern shelf areas (blocks 48.6_4 and 48.6_5), which correspond to spawning and feeding grounds, respectively, have been observed to date. The lack of tag movement between the two areas is similar to those observed in the Amundsen Sea region (SSRUs 88.2C-H) where few tags move between northern seamount area and shelf area. Therefore, population dynamic modelling approach developed for the Amundsen Sea region would provide useful information to understand tag movement patterns in subarea 48.6.