One UK vessel fished around the South Sandwich Islands (Subarea 48.4) in in July, 2005 in accordance with CM 41-03. During this time fish were tagged in order to start a mark-recapture programme to assess the toothfish population. Catch rates were similar to those experienced in Subarea 48.3. The UK proposes to undertake a more extensive mark-recapture experiment in Subarea 48.4 over the 2006 – 2007 fishing seasons. The objective of the experiment will be to assess toothfish population structure and size. The research will be undertaken during April in each year by up to two vessels, details yet to be confirmed. The proposal is to tag 500+ fish taking 100 tonnes of catch each year. The target species will be D. eleginoides but any D. mawsoni caught will also be tagged or retained for analysis as appropriate.