Fig 1.
Synoptic diagram describing the collection of different type of acoustic data from tuna purse seiners (lateral sonar beam, echo-sounder from the work-boat and echo-sounder of the buoy used to track DFADs) as well as the echogram associated to each tool.
Table 1.
Characteristics of the most used echo-sounder buoy models used to track DFADs.
Table 2.
Configuration of the acoustic equipment and calibration parameters.
Table 3.
Summary of the catches of the main tuna species at each DFAD, indicated by set code (year and set number).
Percentages per individuals of each species as well as percentages per weight (indicated with a “w”), mean (L) and standard deviation of the length per species (sdL), total catch and total number of sampled individuals (N) per set are presented. (SKJ: skipjack; BET: bigeye; YFT: yellowfin).
Fig 2.
Frequency response of a) skipjack tuna and b) bigeye tuna at 38, 120 and 200 kHz frequencies.
Fig 3.
Example echograms showing the frequency response of a) skipjack and b) bigeye at 38, 120 and 200 kHz frequencies.
Fig 4.
Scatterplot of total catch against (a) NASCMF, (b) NASC120, (c) NASC200 and (d) NASC38.
Table 4.
Characteristics and results of the most relevant models tested.
(Significance codes for the slope coefficients: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ‘ 1).
Fig 5.
Scatterplots of percentage of the three main tuna species against frequency response ΔMVBS38-200.