An update on the dynamics of the satellite-tracked buoys used in the large-scale purse seine fishery of the Indian Ocean, 2020-2023

In 2023, the DFAD purse seine fishery in the Indian Ocean consisted of 47 large-scale purse seiners assisted by 11 support vessels. The total fishing capacity of the fishery was approximately 100,000 m³ for that year, corresponding to about 74,000 t of fish. Despite recent changes in the fleet, the composition of the fishery has remained stable in recent years. The total number of buoys used in the fishery exhibits significant monthly variability due to the seasonality of the DFAD fishery and the catch limits imposed on purse seiners as part of the yellowfin tuna rebuilding plan. In 2023, an average of 10,700 buoys were used daily in the fishery, equating to roughly 226 buoys monitored daily by each vessel. Maintaining the standing stock of DFADs in purse seine fishing grounds requires continuous deployments to compensate for buoy loss caused by ocean currents, sinking, and retrieval by fishery vessels during buoy transfers to appropriate floating objects encountered at sea. Between January 2020 and December 2023, data collected by the Secretariat indicate that approximately 100,000 buoys were deactivated and replaced to support the fishing activities of the Indian Ocean large-scale purse seine fishery.