Measuring the swimming behaviour of a cultivated pacific bluefin tuna in a submarged aquaculture net cage

为实现日本近海深水网箱养殖蓝鳍金枪鱼的养殖，本研究利用生物测井技术，研究了蓝鳍金枪鱼在水下网箱中的三维游泳行为，并对其长期游泳深度进行了监测。根据标记的金枪鱼的三维轨迹结果，分析了白天和夜间的转弯行为。金枪鱼白天的转弯比夜间的转弯更剧烈。我们使用相对熵来记录游泳深度，以检测摄食和异常行为。由于网箱中碰撞的金枪鱼死亡，近海蓝鳍金枪鱼养殖的渔获率较低。这些结果将有助于了解金枪鱼的行为，以改进网箱，防止鱼类碰撞。

The purpose of this study was to clarify three-dimensional swimming behavior and monitor long-term swimming depth of cultivated bluefin tuna in a submerged cage using the bio-logging technique in order to realize offshore bluefin aquaculture in submerged net cages in Japan. Turning behavior during the day and night was analyzed from the results of three-dimensional trajectories of the tagged tuna. Turning of tuna during the day was sharper than that during the night. We recorded swimming depth using relative entropy to detect feeding and abnormal behaviors. Offshore Bluefin tuna aquaculture has a low yield ratio due to mortality of the colliding tuna in net cages. These results will help understand tuna behavior to improve net cages and prevent fish from colliding.