This paper presents an analysis prepared by the Secretariat and Korea to provide the context to the more variable and anomalously high CPUEs of the two Korean ships the Insung No. 2 and the Insung No. 7 while participating in CCAMLR exploratory fisheries. The operational characteristics of these ships showed distinct differences to the other ships that have participated in longline toothfish fisheries in Divisions 58.4.1, 58.4.2 and subarea 48.6. These differences are reflected in CPUEs with large mean and high variability, arising from periods of repeated low/zero catches and highly spatially and temporally aggregated sets with the largest catches reported across the fleet.