Updated description of Patagonian toothfish (Dissostichus eleginoides) tagging and ageing programs in Division 58.5.2, 1997–2015

In 2014, CCAMLR endorsed a TAC of 4410 t of Patagonian toothfish in Division 58.5.2. This report describes the recent fishing and data collection activities in the fishery. The fleet has expanded to include 6 vessels, 5 operating exclusively longline, and one dual purpose longliner/trawler. To enhance the tagging program that was established in 1998, the fleet has increased tagging rate in this Division from 2 tags/3 tonnes to 2 tags/tonne. Tag overlap statistics across the fleet have been consistently above 80% since 2012. Vessels have also explored new fishing grounds over recent seasons, considerably adding to information on the structure of the population. The ageing program at AAD has produced an additional 2559 estimates of age, for fish captured during the 2014 and 2015 Random Stratified Trawl survey, commercial fishing in 2013/14, and archived otoliths from tagged and recaptured fish from the 2009/10-2013/14 seasons. These samples have detected fish as old as 51 years, increasing the previous maximum age estimate of 42 years. These data have been used to develop age length keys and a revised growth function for inclusion in the 2015 revised stock assessment.