Valérie Mazauric
Abundance estimationFisheries acousticsEcho soundingFisheryBiology
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Publications 10
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Polar Regions are the most vulnerable world areas to any climate change, and therefore can be considered drivers of global climate change, so small and systematic changes in the Polar Regions affect critically the global environment. This is particularly worrying for Europe and the Arctic due to ocean circulation interaction between the North Atlantic and the Arctic Oceans whose outcome is already producing significant climate anomalies in the Northern Hemisphere. Many European countries support...
#1Jesús M. Ibáñez (UGR: University of Granada)H-Index: 27
#2Janire Prudencio (University of California, Berkeley)H-Index: 9
Last. Valérie Mazauric ('IFREMER': IFREMER)H-Index: 5
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The TOMO-ETNA experiment was devised to image of the crust underlying the volcanic edifice and, possibly, its plumbing system by using passive and active refraction/reflection seismic methods. This experiment included activities both on-land and offshore with the main objective of obtaining a new high-resolution seismic tomography to improve the knowledge of the crustal structures existing beneath the Etna volcano and northeast Sicily up to Aeolian Islands. The TOMO ETNA experiment was divided i...
5 CitationsSource
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#1Verena M. Trenkel ('IFREMER': IFREMER)H-Index: 26
#2Laurent Berger ('IFREMER': IFREMER)H-Index: 10
Last. Héctor Villalobos (IPN: Instituto Politécnico Nacional)H-Index: 4
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This paper provides an overview of the progress Ifremer has made recently in fisheries acoustics and the study of small pelagic fish by: i) pushing observation frontiers using a range of platforms including an autonomous un- derwater vehicle, AUV, ii) developing measuring instruments and methods and iii) studying fish distributions. Presently, information from several frequencies of single-beam echosounders is routinely collected together with data from the ME70 multibeam echosounder. For onboar...
27 CitationsSource
#1Egil OnaH-Index: 23
#2Valérie Mazauric ('IFREMER': IFREMER)H-Index: 5
Last. Lars Nonboe AndersenH-Index: 6
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Ona, E., Mazauric, V., and Andersen, L. N. 2009. Calibration methods for two scientific multibeam systems. - ICES Journal of Marine Science, 66: 1326-1334.The new Simrad scientific multibeam systems, the MS70 sonar and the ME70 echosounder, each transmit over many electronically formed beams with centre frequencies spanning from 70 to 120 kHz. Calibrations of these systems are therefore more complex than for conventional split-beam echosounder systems. Two large tungsten-carbide spheres (75 and ...
30 CitationsSource
#1Sébastien Bourguignon ('IFREMER': IFREMER)H-Index: 12
#2Laurent Berger ('IFREMER': IFREMER)H-Index: 10
Last. Valérie Mazauric ('IFREMER': IFREMER)H-Index: 5
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Multibeam echosounders and sonars are increasingly used in fisheries acoustics for abundance estimation. Because of reduced side-lobe levels in the beam-array pattern, the new Simrad ME70 multibeam echosounder installed on board Ifremer's RV Thalassa has been designed to allow improved detection of fish close to the seabed. To achieve this objective, precise and unambiguous detection of the water-bottom interface is required, which raises the issue of bottom detection, especially in the outer be...
8 CitationsSource
#1Verena M. Trenkel ('IFREMER': IFREMER)H-Index: 26
#2Valérie Mazauric ('IFREMER': IFREMER)H-Index: 5
Last. Laurent Berger ('IFREMER': IFREMER)H-Index: 10
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Recently, Simrad in collaboration with Ifremer developed a calibrated, multibeam, vertical echosounder (ME70) for fisheries research. We describe its capabilities and technical limitations. The ME70 has up to 45 beams with distinct frequencies in the range 70–120 kHz, spanning at most 150°. All beams are stabilized in vessel roll and pitch. It has reduced side-lobe levels, up to –70 dB (twoway) instead of the –25 dB (one-way) of conventional systems. We outline research areas for which the ME70 ...
71 CitationsSource
Multibeam echo‐sounders and sonars are increasingly used in fisheries acoustics for studying school structure and behavior and for abundance estimation. However, data quality and a poor signal‐to‐noise ratio obtained with the existing multibeam echo‐sounders preclude quantitative biomass estimation as carried out with the traditional single beam echo‐sounders. In order to overcome these shortcomings, Ifremer and Simrad AS started in 2003 the development of the new and highly flexible calibrated ...
5 CitationsSource