This study was focused on acoustic scattering characteristics of jack mackerel (Trachurus japonicus) at frequency 38, 70, and 120 kHz by Kirchhoff-ray mode (KRM) model. The body length (BL) of 16 individuals ranged in 12.2~22.0 cm (mean±S.D.: 17.8±3.2 cm) and the swimbladder length ranged in 4.2~8.6 cm (mean±S.D.: 6.6±1.6 cm) and the swimbladder cross section ranged in 1.7~6.6 cm2 (mean±S.D.: 3.8±1.6 cm2). This result shows that results correlate well between the BL and the length and cross section of swimbladder. The swimbladder angle ranged in 7~12°and the maximum TS values ranged in –16~–5°at tilt angle. The averaged TS-to-BL relationship were TS38kHz=20log10BL-65.33 (R2=0.66), TS70kHz=20log10BL-65.90 (R2=0.67), and TS120kHz=20log10BL-66.65 (R2=0.65). These results can be used fundamental data in order to estimate distribution and biomass of jack mackerel by using hydro-acoustic method.

• 황강석 | Kangseok HWANG
• 윤은아(국립수산과학원 자원관리과) | Eun-A YOON (Fisheries Resource Research Division, Nataional Fisheries Research & Development Institute, Busan 619-705, Korea) Corresponding author
• 이경훈(국립수산과학원 자원관리과) | Kyounghoon LEE (Fisheries Resource Research Division, Nataional Fisheries Research & Development Institute, Busan 619-705, Korea)
• 이형빈 | Hyungbeen LEE
• 황두진(국립수산과학원 자원관리과) | Doo-Jin HWANG (Fisheries Resource Research Division, Nataional Fisheries Research & Development Institute, Busan 619-705, Korea)