caa a22 4500 397551037 CHVBK 20180308164750.0 cr unu---uuuuu 161202e199604 xx s 000 0 eng 10.1006/jmsc.1996.0064 doi (NATIONALLICENCE)oxford-10.1006/jmsc.1996.0064 Analysis of vessel influence on spatial behaviour of fish schools using a multi-beam sonar and consequences for biomass estimates by echo-sounder [Elektronische Daten] [Marc Soria, Pierre Fréon, François Gerlotto] Biases in the measurements of spatial distribution of fish schools and their consequences for school biomass estimates during conventional acoustic surveys are mainly due to vertical and lateral avoidance of the vessel. In this paper, we quantify school avoidance during an acoustic survey carried out from 13 to 29 May 1994 in the Catalan Sea. From a lateral multi-beam sonar the geometric characteristics (depth, length, width, height, surface, and volume) of 1268 schools were obtained. The 60 beams (1.5°×15°) of the sonar scanned a vertical plane from 0° to 90°, perpendicular to the vessel path within a range of 100 m. Within this plane, the projected area ensonified by the echo-sounder used aboard for acoustic evaluation was evaluated to simulate a comparison between the sonar and the echo-sounder. The results have enabled us to improve our knowledge on the vertical and lateral avoidance patterns of schools in relation to their size, external structure, and their position in the water column, and to quantify the vessel influence on biomass estimated by echo-sounder. © 1996 International Council for the Exploration of the Sea Regular Articles nationallicence acoustic nationallicence avoidance reaction nationallicence multi-beam sonar nationallicence school nationallicence stock assessment nationallicence Soria Marc ORSTOM, 911, Avenue Agropolis, BP 5045, 34032 Montpellier, Cedex 1, France aut Fréon Pierre ORSTOM, 911, Avenue Agropolis, BP 5045, 34032 Montpellier, Cedex 1, France aut Gerlotto François ORSTOM, 911, Avenue Agropolis, BP 5045, 34032 Montpellier, Cedex 1, France aut ICES Journal of Marine Science Oxford University Press 53/2(1996-04), 453-458 1054-3139 53:2<453 1996 53 icesjms https://doi.org/10.1006/jmsc.1996.0064 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1006/jmsc.1996.0064 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Soria Marc ORSTOM, 911, Avenue Agropolis, BP 5045, 34032 Montpellier, Cedex 1, France aut NATIONALLICENCE 700 1- Fréon Pierre ORSTOM, 911, Avenue Agropolis, BP 5045, 34032 Montpellier, Cedex 1, France aut NATIONALLICENCE 700 1- Gerlotto François ORSTOM, 911, Avenue Agropolis, BP 5045, 34032 Montpellier, Cedex 1, France aut NATIONALLICENCE 773 0- ICES Journal of Marine Science Oxford University Press 53/2(1996-04), 453-458 1054-3139 53:2<453 1996 53 icesjms Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford