In the 2012/13 fishing season Spain began implementing a multi-annual Research Plan for Divisions 58.4.1 and 58.4.2 in order to estimate local biomass of Dissostichus spp. by means of two methods: depletion and tagging. In 2014/15 the vessel was unable to conduct the proposed research experience due to problems with a blade of the propeller, During the season 2015/16 is intended to make the same proposed research with some minor changes, always subject to the ice conditions, fulfilling Spain's commitment to return to the same fishing areas in order to study inter-annual variability and maximize tag recovery, as well as, to progress research in these SSRUs (58.4.1H, G, D and C). Two research surveys have been already implemented in Division 58.4.1 and preliminary estimates of local biomass using Leslie depletion analyses have been obtained. Some recoveries of tagged toothfish have been made, both within-season and between-seasons recaptures and a preliminary Age-Length Key of Dissostichus mawsoni has been built after otholits reading from 58.4.1 division specimens. All these data will allow a robust stock assessment attempt by the end of this multiyear research survey.