The swimming behavior of pacific bluefin tuna (Thunnus orientalis) in the offshore sea cage of the brass fishing net was observed and analyzed by imaging sonar techniques. The cultured fish spent most of the time swimming a circular path along the circular cage wall and continued to swim only clockwise direction without completely changing the swimming direction during the 23-hour observation time. In addition, changed swimming behaviors were divided into four categories: (a) the behavior of a large group temporarily swimming in the opposite (counter clockwise) direction, (b) the behavior of a small group temporarily swimming in a small circular path, (c) the behavior swimming small circular path in the center of the cage, and (d) the behavior of a large group swimming across the center of the cage. The maximum swimming speed of the cultured fish was from 3.5 to 3.8 TL/s, the mode was from 1.2 to 1.4 TL/s and the swimming speed during the day time was faster than at night time. It was confirmed the cultured fish swam not only on the surface but also near the bottom net of the cage during the day, but swam mainly at the upper part of the cage at night.

서 론
재료 및 방법
결과 및 고찰
    사육어의 수평 유영행동
    사육어의 유영속도
    사육어의 주야 유영수심 비교
결 론
사 사
References

• 황보규(군산대학교 해양수산관리전공 교수) | Bo-Kyu HWANG (Professor, Oceans and Fisheries Management Major, Kunsan National University, Jeonbuk 54150, Republic of Korea)
• 강명희(경상국립대학교 해양경찰시스템학과 교수) | Myounghee KANG (Professor, Department of Maritime Police and Production System/Institute of Marine Industry, Gyeongsang National University, Tongyeong 53064, Republic of Korea) Corresponding author
• 김민선(군산대학교 해양수산관리전공 교수) | Min-Son KIM (Professor, Oceans and Fisheries Management Major, Kunsan National University, Jeonbuk 54150, Republic of Korea)