Spatial and temporal description of drifting FAD use in the WCPO derived from analyses of the FAD tracking programmes and observer data WCP

This paper presents results from analyses of drifting Fish Aggregating Device (dFAD) use in the Western and Central Pacific Ocean (WCPO), based on information derived from dFAD tracking programmes and observer data. The aims of the paper are to improve the understanding of the use of dFADs in the WCPO, provide better scientific information on the impacts of dFADs and fishing on them; and ultimately inform dFAD management. Three different datasets were used: i) the Parties to the Nauru Agreement (PNA) FAD tracking dataset covering the 2016–2023 period; ii) a recent Western and Central Pacific Fisheries Commission (WCPFC) FAD tracking dataset, of voluntary submission by vessels, that only contained data from early 2023; and iii) observer data, with high observer coverage (average 76–98% of trips) from 2011–2019 but due to the impacts of COVID observer coverage was lower (14–46% of trips) in recent years. After undertaking the filtering, processing and correction procedures, the PNA FAD tracking dataset consisted of 51.7 million transmissions from 107,011 buoys over the 2016–2023 period. As for previous years, areas outside PNA Exclusive Economic Zones (EEZs) are still often missing in 2023 (i.e., “geo-fenced”), which introduces bias to the analyses. Similarly, the WCPFC FAD tracking filtered dataset consisted of 2.5 million transmissions from 10,415 buoys in 2023. While only containing 2023 data, the WCPFC FAD tracking dataset included a larger spatial coverage of transmissions and presented more data available per vessel compared to the PNA FDA tracking dataset. In both datasets most of the buoys used were Satlink (68.6 and 81.8% for the PNA and WCPFC FAD tracking data, respectively); followed by Zunibal (15.7% and 0%); Kato (9.8% and 6.9%) and Marine Instruments (5.9% and 11.3%).