A revision of the research plan for the Spanish exploratory longline fishery for Dissostichus spp in Divisions 58.4.1 and 58.4.2, submitted to the XXXI-WG-SAM, taking into account the suggestions made by the Working Group is presented. Two methods to estimate the local biomass of the toothfish are proposed, a depletion experiment together with the tag of some specimens using the DeLury model and the tag-recapture estimates using the Simple Petersen model.
To evaluate the potential success in achieving the objectives three study areas with high historical effort have been selected in different SSRUs with four different scenarios related to the extent of the area . The regression coefficients between the CPUE and the cumulative catch seem to be a practical way to stablish the area (10 nautical miles) and the minimum effort (0.3 k/hook) to perform the depletion experiment. Historical recaptures of Spanish tagged toothfish were examined within these areas and Subareas/Division (88.1, 88.2, 58.4.1 and 58.4.2). Results strongly related to the effort made within those areas suggest that the likelihood of achieving the objectives with this research plan is high.
