Advances in reducing the interaction with Killer whales and Sperm whales, in the Patagonian Toothfish fishery in CCAMLR subarea 58.7: application of the SAGO Extreme capture system

This work is a synthesis of field data on the use of the SAGO Extreme system on board the Uruguayan fishing vessel Ocean Azul. The campaign was carried out during November and December 2022, in CCAMLR subarea 58.7. The impact of predation was assessed by contrasting the catch per unit effort (CPUE, fish weight/hooks) for fishing lines retrieved in the presence of marine mammals between two conditions: sets with and sets without the SAGO Extreme system. Out of 165 fishing operations, marine mammals were directly observed on 34 occasions, accounting for 20% of the total cases. In these instances, the SAGO system was employed in 14 sets, while in the remaining 20 sets, the system was not utilized. No operational problems were observed with the implementation of SAGO in the area, the ship operated in all the weather conditions that occurred. The highest catch saturation observed with the system was 1.259 kg, considering a single fishing line. Regarding the quality of the catch, live and healthy toothfish were extracted from the SAGO capsules on 11 occasions to be tagged and released alive into the sea. The SAGO technology is in development, so an increase in the avoidance or reduction of the interaction with marine mammals in the Patagonian toothfish fishery is expected.