Effect of Duration and Timing of Acoustic Signal Transmission on Ranched Fish Recapture

Fish were acoustically conditioned, released to a reservoir, called back to a fishing machine and captured. Two timing of capture events (day vs. night) and the duration of the acoustic signal transmission (5 vs. 20 min) were studied and compared. In general, the fish species in this study entered the net pen of the fishing machine to feed during the day and night. No significant difference was found between the 5- and 20-min signal transmission events. Studies of signal duration on the number of acoustically conditioned fish congregating near a sound source are required for different contexts considered for sea ranching to determine the optimal conditioning scheme and signal duration. These should balance distances, the quantity and rate of food provision so that it will be available to fish reaching the feeding location from far away, and the interactions between the species.