Brehmer Patrice auteur aut IRD Sancho G. auteur aut IRD Trygonis V. auteur aut IRD Itano D. auteur aut IRD Dalen J. auteur aut IRD Fuchs A. auteur aut IRD Faraj A. auteur aut IRD Taquet Marc auteur aut IRD text journalArticle eng text/pdf reformatted digital access This work presents a methodological synthesis for the in situ monitoring of fish aggregating devices (FADs) using a combination of optical, echosounder and SCUBA observations conducted in the vicinity of drifting FADs. The acoustic methods allowed, according to the devices used, the description of the spatial organisation and dynamics of biotic scattering layers, individual fishes, schools, shoals and mammals, while visual, photographic and video observations permitted species identification within a range of 0 to 25m. Based on these results, we elaborate on the interest to combine acoustic and visual methods, and present an autonomous instrumented drifting buoy for remotely monitoring fish diversity and abundance in the pelagic ecosystems. The perspective of autonomously collecting large amounts of basic information useful for ecological and fisheries studies in an ecosystem approach for open sea, as well as coastal pelagic environment, is also emphasized. As perspective we present Seaorbiter a futuristic large drifting platform which will allow performing innovative ecosystemic studies taking into account simultaneously all macro components of the pelagic ecosystem. specialized Optical Census Acoustics Buoy Seaorbiter Biomonitoring Conservation Environmental monitoring Fish Pelagic SEYCHELLES OCEAN INDIEN 036 040 35 1 177-189 2019 0212-5919 https://www.documentation.ird.fr/hor/fdi:010075533 10.1007/s41208-018-0107-9 0212-5919 [F B010075533] https://www.documentation.ird.fr/hor/fdi:010075533 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/divers19-04/010075533.pdf IRD - Base Horizon / Pleins textes 2019-05-13 2025-02-24 fdi:010075533 fre