This new research plan aims to update information for toothfish in Subarea 48.3A during the 2025/26-2027/28 fishing seasons. No toothfish (Dissostichus spp.) data has been collected in Subarea 48.3A since 2005. The proposed longline survey will update the information for Subarea 48.3A and complement the research in adjacent areas 48.3B. The primary objectives are to obtain a relative abundance estimate, characterize the length/age structure, sex ratio, collect reproductive data, collect biological data for by-catch species, and continue the CCAMLR Tagging and Recapture Program for toothfish in Subarea 48.3.
To obtain a representative and unbiased relative estimate of toothfish abundance, Chile proposes using the fishing vessel (FV) Globalpesca I to carry out stratified random sampling (StRS) with three depth strata: 600-1000, 1000-1500 and 1500-2000 meters. Similarly, a two-stage cluster sampling design will be used to obtain representative length/age structure of toothfish. Based on the StRS, it was determined that 48 sampling stations are necessary to estimate a mean Catch Per Unit Effort (CPUE) with a Coefficient of Variation (CV) of 12% (corresponding to a margin of error of 300 kg/2500 hooks). The survey will use standardized fishing operations and gear (e.g., 2500 hooks per longline and trotline). The proposed catch limit for the research surveys is 76 tonnes each season. This proposed catch limit was determined through analysis of historical CPUE data and applying a 25% precautionary buffer to accommodate variability in catch rates and ensure the completion of all planned stations.
This multi-year study aims to provide critical data for stock assessments, improve understanding of toothfish biology and population dynamics, and support CCAMLR's conservation and management objectives in the Southern Ocean. Annual progress reports will be submitted to relevant CCAMLR working groups for review and feedback.