Development of Sound-Fish Aggregating Devices (S-FAD) Applied at Lift Net

Abstract

Fish produced sound from internal organs and air bubbles caused by the friction of fish bodies with the surrounding water. The sounds are used to interact with each other, and the sound produced is stronger when gathered during eating. The study aimed to develop a sound-fish aggregating device (S-FAD) and produce an artificial fish sound with suitable frequency for several fish species. The study used analytical descriptive and experimental fishing, which divided into two steps, (1) S-FAD tool construction using a descriptive method to explain every step in the construction of tool and consideration in the use of supporting tools, and (2) effectiveness testing step using an experimental fishing method to see the horde pattern (behavior) and the target strength using an echosounder. The sound wave aids trial was carried out on a lift net from morning to noon. Data retrieval by recording the fish-finder screen was carried out for 1 minute before and after the sound wave device was put into the water. The S-FAD test was done 60 times and hauling lift net in every multiple of 4 trials. The results showed that the average fish that approached and came together before and after the S-FAD installation was 2.18 ± 0.98 and 2.79 ± 0.71 fish. The highest number of caught fish when hauling at lift net with four times repetition was 79 fish from 7 types, including Selaroides leptolepis, Stolephorus sp., Sphyraenidae sp., Scatophagus argus, Mugil sp., Portunus pelagicus, and Loligo sp.