Preliminarily analyses of the regional database of stranded drifting FADs in the Pacific Ocean

Drifting Fish Aggregating Devices (dFADs) are reaching coastal areas where they can become stranded, adding to pollution and/or causing environmental damage. To quantify these events and their impacts, several Pacific Island Countries and Territories (PICTs), in collaboration with the Pacific Community (SPC) and international Non-Governmental Organisations (NGOs) have started programmes to collect in-situ data. These data collection programs on stranded and lost dFADs are fully implemented in seven PICTs to date: the Cook Islands, Wallis and Futuna, the Federated States of Micronesia (FSM), the Republic of the Marshall Islands (RMI), French Polynesia, Palmyra and Hawaiʻi, and are starting this year in New Caledonia and Tuvalu. A total of 1,159 stranding events were identified in the 2009–2022 period in all the PICTs considered; 45.4% were of a buoy alone; 30.0% of a FAD alone and 19.0% of a FAD with a buoy attached (the rest corresponding to entries with unknown presence of buoys and FADs). Most FADs found were dFADs, in whole or in part, although in FSM and RMI anchored FADs (aFADs, “Payao") were commonly found stranded. Most buoys found were dFAD satellite buoys from Satlink, Marine Instruments and Zunibal brands. In the PICTs where the data collection program is implemented, the spatial distribution of stranding events was wide. Higher numbers of stranding events per 1° cell were detected in Wallis and Futuna, the Cook Islands and French Polynesia, though this could be due to higher data collection effort in some locations. In terms of habitat where FADs and buoys were most commonly found, 39.0% were found on a beach, 27.5% had been previously collected by local communities and were recorded as found in gardens or private homes; 7.6% were found drifting in the ocean and 6.8% were stuck on coral reefs. The fate of FADs and buoys was also investigated, though this information often was not recorded (no record for 18.1% of buoys and 61.4% of FADs). For those with a recorded fate, 74.1% of the buoys and 25.7% of the FADs were removed from the habitat; the rest were left where found. Most FADs were found without submerged appendages attached (60.9%), although this information was often not recorded (18.4% of the findings). When recorded, dFAD flotation materials were i) bamboo; ii) bamboo and floats; or iii) floats. Flotation materials for the aFADs found in FSM and RMI were metal drums or fiberglass. In terms of materials related to raft covering and submerged appendages, when present, they were mostly netting and ropes (53.5%); or a combination of netting, ropes, plastic sheeting, and canvas. Netting was absent in 31.6% of FADs; present in 36.2% of FADs but without details about mesh size; present with a small mesh size (13.3%); present with a large mesh size (10.6%); and present with both small and large mesh sizes (8.3%). Very little environmental damage was recorded in the stranding FADs database. When damage was noticed, it was coral damage (4.8% of all FADs); pollution (3.3%); turtle body parts (0.5%); and dead birds (0.2%). Most of these were recorded for dFAD stranding events and in particular when the dFAD still retained submerged appendages. In terms of other animals found interacting with the stranded FADs, or the aggregation of fish and fishing occurring near shore when lost and abandoned FADs are still in the water, this also was relatively rare with five fishing sets on dFADs recorded and aggregated fish detected around nine dFADs and three aFADs. The origin of the FADs and buoys found stranded in the Western and Central Pacific Ocean (WCPO) was investigated by i) using markings on the satellite buoy to determine vessel owner, flag and Convention Area (CA) of fishing; and ii) matching buoy ID number with the PNA FAD tracking database and/or the Western and Central Pacific Fisheries Commission (WCPFC) and Inter-American Tropical Tuna Commission (IATTC) observer databases. Where possible, the buoy’s last known position and date and flag of origin of the vessel monitoring the buoy were identified. This second method also allowed comparison of the fate of the buoys recorded in the PNA FAD tracking database with their detected stranding event. Most buoys (and FADs when still attached) found stranded were from vessels fishing in the WCPFC (52.6%), followed by IATTC (38.7%) and both CAs (8.7%); and the last known position was in the WCPFC-CA (65.8%) or the IATTC-CA (34.3%). There was large variability in terms of country of origin for stranding events. Most stranding events in French Polynesia were from the IATTC-CA (Ecuadorian, US, Panama vessels); and in FSM almost only from the WCPFC-CA although from a wide range of fleets. In Wallis and Futuna buoys were mostly from the WCPFC-CA (more than 65.0%), and from vessels flagged US, Korea, Kiribati and Ecuador. In the Cook Islands, buoys presented a last known position in the WCPFC-CA (75.0%), from vessels fishing in the WCPFC-CA (33.3%), both CAs (44.4%) or the IATTC (22.2%) (US, Korean, Ecuadorian and El Salvadorian vessels). The EEZ of the last known position was also investigated to detect potential patterns of origin by stranding areas. For the 82 stranded buoys that could be matched with the PNA FAD tracking database, the fate of these dFADs, as classified in the PNA FAD tracking data was investigated. First, it was found that many buoys were not classified as stranded in the PNA FAD tracking database because they were on atolls that were not present in the digital map used to define the coastlines. Using a higher resolution map, an updated classification of dFAD fate from the PNA FAD tracking data was compiled. This highlighted that 18.3% of the stranded buoys also found in the PNA FAD tracking data were classified as beached; 3.7% recovered close to shore and 2.4% in port. However, 59.8% and 12.2% were still classified as still drifting or lost at the end of their trajectory, while they were ultimately found beached in one of the PICTs. This highlighted the fact that stranding events using the PNA FAD tracking data only are highly under-estimated, mainly due to deactivation of buoys when they drift outside the main fishing grounds and high rates of FAD (re)appropriation at sea. We invite WCPFC-SC18 to: - Highlight the need for in-situ data to be collected to better quantify dFAD stranding events and the impacts of dFADs on marine and coastal ecosystems. - Note the development and progress of the in-country data collection programmes on stranded and lost dFADs nearshore and of a regional database; as well as the need to explore potential FAD retrieval programs as a measure to mitigate the impacts of lost FADs. - Note the preliminary results from analyses of the regional database presented in this paper. - Note the need for trajectory data, including historical periods, from both the IATTC and WCPFC convention areas to better determine the origin of FADs and buoys found stranded. - Encourage the extension of the in-country data collection programmes to other members of WCPFC.