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Correction of beam overlap-induced athwart distortion in multibeam sonars

Bibliographic Details
Title: Correction of beam overlap-induced athwart distortion in multibeam sonars
Authors: Guillermo Boyra, Udane Martínez, Jon Uranga, Gala Moreno, Héctor Peña
Source: ICES Journal of Marine Science. 80:197-209
Publisher Information: Oxford University Press (OUP), 2022.
Publication Year: 2022
Subject Terms: 0106 biological sciences, SCHOOLS, FISH, purse-seiner, DENSITY, TARGET-STRENGTH, 14. Life underwater, tropical tuna, 01 natural sciences, dFAD
Description: A method is proposed to estimate and correct athwart-beam distortion of multibeam sonars to advance sonar-based abundance estimation. We illustrate its application using data from a Simrad SN90 multibeam sonar aboard a tropical tuna purse-seiner, targeting mixed fish aggregations around drifting Fish Aggregating Devices (dFADs) in the Atlantic Ocean. To calculate the distortion in the horizontal swath, athwart-beam measurements were compared with the more accurate simultaneous along-beam measurements. For the vertical swath correction, we used as reference a vertically oriented single, split beam echosounder simultaneously monitoring the same aggregations. Along-to-athwart ratios of ∼0.6 and ∼0.3 were estimated for the horizontal and vertical swaths, respectively, at ranges involved during purse-seine operations in this fleet (from ∼225 to ∼325 m). Additionally, equations were developed to analytically describe the athwart distortion due to overlap between contiguous beams. Once corrected for distortion, typical school morphology measures were provided for tuna aggregations around dFADs.
Document Type: Article
Language: English
ISSN: 1095-9289
1054-3139
DOI: 10.1093/icesjms/fsac226
Access URL: http://dspace.azti.es/handle/24689/1678
Rights: CC BY
Accession Number: edsair.doi.dedup.....5bbe7a483ee7350b8403b6670aa0592c
Database: OpenAIRE
Description
ISSN:10959289
10543139
DOI:10.1093/icesjms/fsac226