Please use this identifier to cite or link to this item: http://dspace.azti.es/handle/24689/788
Files in This Item:
There are no files associated with this item.
Title: Target strength of skipjack tuna (Katsuwanus pelamis) associated with fish aggregating devices (FADs)
Authors: Boyra, Guillermo; Moreno, Gala; Sobradillo, Bea; Perez-Arjona, Isabel; Sancristobal, Igor; Demer, David A.
Citation: ICES JOURNAL OF MARINE SCIENCE, 2018, 75, 1790-1802
Abstract: This paper presents measures of target strength (TS; dB re 1 m(2)) and models of TS vs. fork length (L; cm), i.e. TS = 20log(L) + b(20), for skip-jack tuna associated with fish aggregating devices (FADs) in the Central Pacific Ocean. Measurements were made using 38-, 120-, and 200-kHz split-beam echosounders on a purse-seine workboat during fishing operations. To mitigate potential bias due to unresolved targets, TS measurements were rejected if they were not simultaneously detected with multiple echosounder frequencies in approximately the same location. The filtered TS and concomitantly sampled L data were used to estimate b(20) = -76, -71, and -70.5 dB for 38, 120, and 200 kHz, respectively, using the method of least squares. For comparison, quasi-independent estimates of TS and b(20) were calculated from acoustic echo-integration and catch data representing entire aggregations around the FADs. The results differed by <= 1 dB for all three frequencies. The sensitivities of these results to variations in fish morphology and behaviour were explored using a simulation of TS for fish without swimbladders. The utility of the results on acoustic properties of skipjack tuna and next research steps to achieve selective fishing at FADs are discussed.
Keywords: acoustics; echosounder; FAD; frequency response; multiple targets; selectivity; sonar; split beam; tropical tuna; tuna; MACKEREL SCOMBER-SCOMBRUS; MULTIPLE-FREQUENCY METHOD; SPLIT-BEAM ECHOSOUNDER; ATLANTIC MACKEREL; ACOUSTIC BACKSCATTERING; THUNNUS ALBACARES; SCHOOLS; IDENTIFICATION; TELEMETRY; FISHERIES
Issue Date: 2018
Publisher: OXFORD UNIV PRESS
Type: Article
Language: English
DOI: 10.1093/icesjms/fsy041
URI: http://dspace.azti.es/handle/24689/788
ISSN: 1054-3139
E-ISSN: 1095-9289
Funder: International Seafood Sustainability Foundation (ISSF)
government of Kiribati
government of Tuvalu
government of Tokelau
Appears in Publication types:Artículos científicos



Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.