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	Provedor de dados ArchiMer (3) OceanDocs (1) Autor Castro Machado, F. (1) Doray, Mathieu (1) Guillon, Laurent (1) Hammerstad, E (1) Lurton, Xavier (1) Madirolas, A. (1) Pohner, F (1) Mais... Palavra-chave Echosounding (4) Multibeam sonar (2) Acoustic properties (1) Acoustique (1) Advection diffusion models (1) Aggregative behaviour (1) Backscatter (1) Bathymetry (1) Coastal fisheries (1) Comportement agrégatif (1) DCP (1) Echo surveys (1) Echosounders (1) FAD (1) Geostatistics (1) Géostatistique (1) Hierarchy (1) Hiérarchie (1) Http://aims.fao.org/aos/agrovoc/c_16370 (1) Http://aims.fao.org/aos/agrovoc/c_1696 (1) Mais... Tipo do documento Text (3) Journal Contribution (1) Ano 2006 (1) 2001 (1) 1998 (1) 1990 (1) País France (3) Belgium (1) Idioma Inglês (2) Espanhol (1) Francês (1)		Ordenar por:  Relevância Autor Título Ano Registros recuperados: 4 Primeira ... 1 ... Última L'agrégation de thons de sub-surface au sein du système [DCP ancré - macronecton - environnement - pêche] en Martinique : étude hiérarchique par méthodes acoustiques, optiques et halieutiques ArchiMer Doray, Mathieu. Artificial Fish Aggregating Devices (FADs) are known to concentrate tropical tunas. This aggregative behaviour drastically increases the vulnerability of these species to fishing. Alternatively, FADs can be used as oceanic observatories to study the aggregative behaviour of large pelagic fish. We conducted sea surveys in Martinique (Lesser Antilles) to i) establish a typology of the pelagic fish aggregations found around moored FADs ii) study their relations with their biotic and abiotic environment and the local fishery. The mean biomass of large pelagic fish aggregations was also estimated to provide scientific inputs to achieve a sustainable management of the moored FAD fishery. The first part presents the background of the study. We introduce the... Tipo: Text Palavras-chave: Martinique; Lesser Antilles; Hierarchy; Advection diffusion models; Geostatistics; Micronekton; Tuna/environment relationships; Aggregative behaviour; Tuna; Underwater video; Echosounding; FAD; Martinique; Petites Antilles; Hiérarchie; Modèles d'advection diffusion; Géostatistique; Micronecton; Relation thon/environnement; Comportement agrégatif; Thon; Vidéo sous marine; Acoustique; DCP. Ano: 2006 URL: http://archimer.ifremer.fr/doc/2006/these-1735.pdf Ultra Wide Swath Sea interferometric multibeam echo sounder with sea bottom imaging system. ArchiMer Hammerstad, E; Pohner, F. The SIMRAD EM12 is a new full ocean depth multibeam echo sounder, operating at 13 kHz. By use of interferometric signal processing techniques it will achieve an ultra wide swath geometry of 150 degrees, corresponding to 7.5 times the depth of water. The system will in addition to the bathymetry produce a fully corrected sidescan sonar image of the seafloor, on to the depth soundings, the EM12 has the capability to generate a sidescan image of the seabed. Tipo: Text Palavras-chave: Ocean floor; Multibeam sonar; Bathymetry; Signal processing; Sonar imagery; Imaging techniques; Side scan sonar; Echosounding; Echosounders. Ano: 1990 URL: http://archimer.ifremer.fr/doc/1990/acte-1141.pdf Backscattering from buried sediment layers: The equivalent input backscattering strength model ArchiMer Guillon, Laurent; Lurton, Xavier. Signals received by low-frequency multibeam echosounders are strongly affected by sound penetration inside the upper sediment layers and by backscattering from buried layers down to depths of a few meters; this may lead to serious ambiguities and misinterpretations of experimental data. These phenomena are modeled here using a concept of equivalent input backscattering strength (EIBS), based on a combination of classical models of local backscattering strength and propagation inside fluid layered media. The local backscattering strength at a buried interface is expressed first to account for the impedance adaptation due to the overlying layers, for the angular refraction effects due to the velocity profile, and for the layered structure of the underlying... Tipo: Text Palavras-chave: Sound propagation; Sediment structure; Multibeam sonar; Echosounding; Backscatter; Acoustic properties; Sediment properties. Ano: 2001 URL: http://archimer.ifremer.fr/doc/2001/publication-729.pdf Observaciones sobre la distribución vertical y caracterización de los registros ecoicos de algunas especies de peces costeros en la plataforma bonaerense. November 1994 OceanDocs Madirolas, A.; Castro Machado, F.. Acoustic data were recorded by means of a scientific echosounder, during a survey carried out with R/V Dr. E.L.Holmberg in the coastal region off Buenos Aires, Argentina. Data were obtained in correlation with bottom trawl stations, aiming at characterizing the echo recording of several coastal fish species. Echo recording of the following species could be identified: white croaker Micropogonias furnieri, striped weakfish Cynoscion striatus, horse mackerel Trachurus lathami and red porgy Sparus pagrus. From these, some aspects of fish behaviour are described.In situ target strength measurements were taken with a split-beam transducer for striped weak fish, obtaining mean values of -43.9 dB and -42.9 dB for fish with mean length 17.0 cm and 18.5 cm... Tipo: Journal Contribution Palavras-chave: Echo surveys; Marine fish; Echosounding; Vertical distribution; Coastal fisheries; Echosounding; Coastal fisheries; Http://aims.fao.org/aos/agrovoc/c_16370; Http://aims.fao.org/aos/agrovoc/c_1696. Ano: 1998 URL: http://hdl.handle.net/1834/2474 Registros recuperados: 4 Primeira ... 1 ... Última

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