FN Archimer Export Format PT J TI Multibeam sonar detection of suspended mussel culture grounds in the open sea: Direct observation methods for management purposes BT AF BREHMER, Patrice VERCELLI, Catherine GERLOTTO, Francois SANGUINEDE, Fabien PICHOT, Yves GUENNEGAN, Yvon BUESTEL, Dominique AS 1:1;2:2;3:1;4:1;5:2;6:2;7:3; FF 1:;2:PDG-DOP-LER-LERLR;3:;4:;5:PDG-DOP-LER-LERLR;6:PDG-DOP-DCM-HMT-RHSETE;7:PDG-DOP-DCOP; C1 IRD, CRHMT, F-34203 Sete, France. IFREMER, LER LR, F-34203 Sete, France. IFREMER, COP, Tahiti, France. C2 IRD, FRANCE IFREMER, FRANCE IFREMER, FRANCE SI BREST SETE TAHITI SE IRD PDG-DOP-LER-LERLR PDG-DOP-DCM-HMT-RHSETE PDG-DOP-DCOP IN WOS Ifremer jusqu'en 2018 copubli-france copubli-p187 IF 2.081 TC 14 UR https://archimer.ifremer.fr/doc/2006/publication-1672.pdf LA English DT Article DE ;Management;Sonar;Open sea;Long line;Mussel AB The exploitation of offshore mussel farms is becoming important throughout the world, but monitoring this activity remains a difficult task. Here, we propose a specific method for this purpose. A total of 140 long-lines were monitored on a mussel culture ground in the French Mediterranean Sea during four experimental surveys deploying multibeam sonar devices mounted on poles (Reson Seabat 6012, 455 kHz) on small boats. This allowed geo-referenced observations to be made of the submerged mussel long-lines, as well as three-dimensional (3D) drawings of the long-line structures and the sea bed shapes, using long-line longitudinal sonar sampling. Three sonar data-analysis methods were applied: (i) direct two-dimensional (2D) visual interpretation of raw sonar video images; (ii) indirect 2D long-line drawings; and (iii) 3D digital long-line reconstructions. The development of these acoustic methods in shallow water provides scientists, managers and local authorities with a tool for observing the 3D position (geographical position and depth) of mussel cultures, for counting each structure by the 'long-line echo-counting' method, for monitoring their shape in situ, and for classifying the mussel rope segments into three growth categories ('in growth', 'full' and 'empty'). The use of acoustic tools for monitoring underwater mussel culture grounds, for management purposes and for scientific studies, could be extended to other artificial structures in shallow water environments. (c) 2005 Elsevier B.V. All rights reserved. PY 2006 PD MAR SO Aquaculture SN 0044-8486 PU Elsevier VL 252 IS 2-4 UT 000235784200014 BP 234 EP 241 DI 10.1016/j.aquaculture.2005.06.035 ID 1672 ER EF