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| Registros recuperados: 13 | |
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| Bez, Nicolas; Reid, David; Neville, Suzanna; Verin, Yves; Hjellvik, Vidar; Gerritsen, Hans D.. |
| Acoustic data are often collected during bottom trawl surveys. Their use can potentially improve the precision and accuracy of fish abundance estimates if acoustic data collected between trawl stations are consistent with those collected during trawling operations. This question is addressed here through the analysis of 20 bottom trawl surveys (three survey areas and five different survey series) with coincident acoustic measurements during and between trawl stations. Firstly, on-station and underway acoustic data were compared using statistics computed globally over each survey (average vertical profiles, global indices of collocations, and spatial structures) for various combinations of depth layers. Secondly, we focussed on underway acoustic data... |
| Tipo: Text |
Palavras-chave: Gear perturbation; Acoustic; Bottom trawl. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2486.pdf |
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| Masse, Jacques. |
| Eight acoustic surveys were carried our in the Bay of Biscay, during 1989-94, to study the distribution and abundance of anchovy (Engraulis encrasicolus, L.) in that area. Acoustic data were stored using the INES/MOVIES acquisition and processing system. Species-specific distribution patterns were confirmed through complementary sampling with a mid-water trawl. This paper summarises the combination of technical procedures used for acoustic assessments, and the results of acoustic surveys in the Bay of Biscay that pertain to the dynamics of this stock. Information is presented on the distribution and abundance of anchovy and co-occuring species, and on the movement patterns detected within the pelagic fish community, in relation to environmental conditions.... |
| Tipo: Text |
Palavras-chave: Acoustic; Anchovy; Engraulis encrasicolus; Schooling; Pelagic; Behaviour; Bay of Biscay. |
| Ano: 1996 |
URL: http://archimer.ifremer.fr/doc/00191/30265/28719.pdf |
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| Diner, Noel. |
| Models of simulated schools have been used to determine the intrinsic variability in echotraces due to beam pattern effect. This work concerns only morphometric and energetic parameters that can be extracted from echotraces. It appears that dST, the difference between school density and processing threshold is a key parameter, which directly influences the concerned detection angles. Relations, taking into account dST but also, Nbi, the relative school length image compared to the beam width, have been settled for the calculation of length and density corrections. In most cases, corrected values are obtained with errors less than respectively 5% for length and 0.5 dB for density (reverberation index), provided that the Nb-i value is 1.5 or more. When Nb-i... |
| Tipo: Text |
Palavras-chave: Banc de poissons; Détection de poissons; Acoustique; Fish schools; Fish detection; Acoustic. |
| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/2001/publication-546.pdf |
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| Receveur, Aurore; Kestenare, Elodie; Allain, Valerie; Ménard, Frédéric; Cravatte, Sophie; Lebourges-dhaussy, Anne; Lehodey, Patrick; Mangeas, Morgan; Smith, Neville; Radenac, Marie-hélène; Menkes, Christophe. |
| Acoustic data are invaluable information sources for characterizing the distribution and abundance of mid-trophic-level organisms (micronekton). These organisms play a pivotal role in the ecosystem as prey of top predators and as predators of low-trophic-level organisms. Although shipboard-ADCP (acoustic Doppler current profiler) acoustic backscatter signal intensity cannot provide an absolute biomass estimate, it may be a useful proxy to investigate variability in the distribution and relative density of micronekton. This study used acoustic recordings data spread across 19 years (1999–2017) from 54 ADCP cruises in New Caledonia’s subtropical EEZ (exclusive economic zone) to assess seasonal and interannual variabilities and spatial distribution of... |
| Tipo: Text |
Palavras-chave: Micronekton; Southwest Pacific ocean; SEAPODYM; Acoustic; Ecosystem. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00609/72078/70794.pdf |
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| Ker, Stephan; Le Gonidec, Yves; Marie, Louis; Thomas, Yannick; Gibert, Dominique. |
| Seismic Oceanography is coming of age as an established technique of observation of the thermohaline structure of the ocean. The present paper deals with the seismic reflectivity of the Armorican Shelf seasonal thermocline, west of France, based on two seismic experiments performed with a sparker source. The peak frequency was 500 Hz for the ASPEX experiment, where the thermocline was located at 27 m water depth, and reduced to 400 Hz associated to a higher source level for the IFOSISMO experiment, where the thermocline was 12 m deeper. Despite this settings, only the first experiment could clearly highlight the thermocline reflector, providing the first seismic observation of a shallow oceanic structure. To better understand the limitation of... |
| Tipo: Text |
Palavras-chave: Thermocline; Seismic method; Wavelet analysis; Acoustic. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00254/36535/35066.pdf |
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| Parmentier, Eric; Tock, Jeremy; Falguiere, Jean-claude; Beauchaud, Marilyn. |
| The red drum Sciaenops ocellatus is an estuarine-dependent sciaenid that has supported important recreational and commercial fisheries for many years. Since the 1980s, this species has been farmed in different regions of the world and studies have been conducted to find natural ways to improve its culture. Sciaenops ocellatus is well known for making calls but studies on this characteristic have been mainly restricted to passive acoustics. The aim of this study was to provide acoustic-related information that could be useful in rearing practices. We have studied in detail fish calling characteristics, described their sound-producing mechanism and tested the recordings in different kinds of confinements (floating cages, concrete and fibreglass tanks).... |
| Tipo: Text |
Palavras-chave: Acoustic; Red drum; Sonic; Muscle morphology. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00190/30127/28589.pdf |
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| Duhamel, Erwan; Biseau, Alain; Masse, Jacques; Villalobos, Hector. |
| The french fishery of anchovy is divided in two groups defined by gears : purse seine and pelagic trawl. The average length of these vessels is about 20m. This fleet is very opportunistic : all trawlers are using several trawls during the year, to catch sometimes bass, tuna, hake, or scampi, and purse seine are mainly fishing sardine. Each year, the main anchovy catches are provided by pair trawlers. Purse seiners operate often in coastal areas (<10 nautical miles); trawlers may operate until 50 nautical miles offshore but are banned inside the three miles coastal zone. The pair trawlers may operate from Basque country to western Channel according to fish availability. Purse seiners usually stay around their home harbour. |
| Tipo: Text |
Palavras-chave: Pelagic trawl; Purse seine; Anchovy; Bay of Biscay; Acoustic; Survey; ICES; PELGAS; Chalut pelagic; Bolinche; Anchois; Golfe de Gascogne; Acoustique; Campagne oceanographique; CIEM; PELGAS. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/2004/acte-2296.pdf |
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| Registros recuperados: 13 | |
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