Thambithurai Davide auteur aut IRD Jauharee A. R. auteur aut IRD Baidai Y. auteur aut IRD Forget Fabien auteur aut IRD Dupaix A. auteur aut IRD Adam M. S. auteur aut IRD Dagorn Laurent auteur aut IRD Capello Manuela auteur aut IRD text journalArticle eng text/pdf born digital access Tropical tuna species are among the world's most commercially important fish. Numerous industrial and artisanal fisheries in developing countries target them using artificial floating structures (Fish Aggregating Devices or FADs). Although tunas' associative behaviour with such structures is well known to fishers, knowledge of how they interact with FADs remains fragmentary. Using echo-sounder buoy data attached to FADs, we assessed tuna aggregation dynamics within an array of anchored FADs (aFADs) in the Maldives-one of the world's leading tuna fishing nations-over two years (2017-2018). Predictions of tuna presence and absence from a random forest model showed good accuracy when evaluated against semi-quantitative logbook data (78 %) but performed poorly with phone survey data (similar to 49 %). Occupancy at aFADs exceeded 60 % in both years, peaking above 80 % each April. This suggests FAD density is low enough for continuous use by tuna, the population is large enough to sustain occupancy, or both. Aggregations' continuous residence time (aCRT) averaged 7.96 days, while continuous absence times (aCAT) averaged 3.89 days. Both metrics followed exponential distributions, suggesting the underlying biological process is time-independent and memoryless. Spatial autocorrelation showed partial correlation in tuna absence among aFADs, despite some local effects, supporting previous findings that aFADs in the Maldives do not function as a network. These findings highlight the value of echo-sounder buoy data, offering robust aggregation metrics and insights into tuna behaviour that could inform fisheries management. specialized Tropical Tunas Fish Aggregating Devices (FADs) Pole-and-Line Spatial Ecology Fisheries Management Acoustic monitoring MALDIVES OCEAN INDIEN 040 288 107462 [10 p.] 2025 0165-7836 https://www.documentation.ird.fr/hor/fdi:010094412 10.1016/j.fishres.2025.107462 0165-7836 [F B010094412] https://www.documentation.ird.fr/hor/fdi:010094412 https://www.documentation.ird.fr/intranet/publi/2025-09/010094412.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2025-09-24 2025-09-24 fdi:010094412 fre