This new research plan aims to update information for toothfish in Subarea 48.2 in the Northern (NRB) and Southern Research Blocks (SRB) during the 2025/26-2027/28 fishing seasons. The primary objectives are to obtain relative abundance estimates, characterize the length/age structure, collect reproductive data, collect biological data for by-catch species, and continue the CCAMLR Tagging and Recapture Program for toothfish in Subarea 48.2.
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 with proportional allocation, it was determined that 64 sampling stations across the NRB and 34 across the SRB 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) like previous Ukrainian surveys from 2015 to 2019 to ensure data comparability. Based on historical fishing data analysis from 2015-2018, it is estimated that 188 tons are needed with 133 tons and 65 tons allocated to NRB and SRB respectively, with these allocations representing 65.3% and 34.7% of the total survey effort.
No data has been collected for toothfish in Subarea 48.2 since 2019. The survey design will complement existing data and thus update research in this data-limited fishery. 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.