Sound properties produced by Korean rockfish Sebastes schlegelii in relation to body and swim bladder size

The aim of this study was to understand the relationship between acoustic characteristics and body size of Korean rockfish Sebastes schlegelii in order to better estimate the body length of S. schlegelii by passive acoustic techniques. In this study, S. schlegelii , with a body length ranging from 21.7 to 24.8 cm (mean ± SD = 23.33 ± 0.93 cm) and a body weight of 144.2 to 250.3 g were selected as subjects. The aim was to explore the relationship between the acoustic characteristics of the fish and their standardized lengths through aquarium experiments. The vocalization frequency exhibited a main peak at around 150 Hz, a sub-peak at approximately 100 Hz, and the primary vocalization band extended from 100 to 350 Hz, with a pulse duration of 15.2 ± 2.4 ms. The results indicated that the peak frequency was negatively correlated with the standardized length, swim bladder length, width, and height (p <0.001). This research contributes to the understanding of the relationship between acoustic properties and body size and suggests the potential utility of passive acoustic monitoring techniques for estimating the body lengths of target species.