The Pacific sleeper shark Somniosus pacificus is one of the largest predators in deep Suruga Bay, Japan. A single individual of the sleeper shark (female, ~300 cm in total length) was observed with two baited camera systems deployed simultaneously on the deep seafloor in the bay. The first arrival was recorded 43 min after the deployment of camera #1 on 21 July 2016 at a depth of 609 m. The shark had several remarkable features, including the snout tangled in a broken fishing line, two torn anteriormost left-gill septums, and a parasitic copepod attached to each eye. The same individual appeared at camera #2, which was deployed at a depth of 603 m, ~37 min after it disappeared from camera #1 view. Finally, the same shark returned to camera #1 ~31 min after leaving camera #2. The distance between the two cameras was 436 m, and the average groundspeed and waterspeed of the shark were 0.21 and 0.25 m s−1, respectively, which were comparable with those of the Greenland shark Somniosus microcephalus (0.22–0.34 m s−1) exhibiting the slowest comparative swimming speed among fish species adjusted for size. The ambient water temperature of the Pacific sleeper shark was 5.3 °C, which is considerably higher than that of the Greenland shark (~2 °C). Such a low swimming speed might be explained by the ‘visual interactions hypothesis’, but it is not a consequence of the negative effects of cold water on their locomotor organs.

中文翻译：

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使用诱饵相机阵列首次记录太平洋睡鲨 Somniosus pacificus 的游泳速度

太平洋沉睡鲨太平洋睡梦是日本骏河湾深处最大的掠食者之一。在海湾深海海底同时部署了两个带诱饵的摄像系统，观察到一个睡鲨个体（雌性，总长约 300 厘米）。第一次到达是在 2016 年 7 月 21 日在 609 m 深度部署 1 号摄像机后 43 分钟记录的。这条鲨鱼有几个显着的特征，包括被断了的钓鱼线缠住的鼻子、两个撕裂的最前面的左鳃隔膜，以及每只眼睛都附有一只寄生桡足类动物。同一个人出现在 2 号摄像机上，该摄像机被部署在 603 m 的深度，在它从 1 号摄像机视图中消失后约 37 分钟。最后，同一条鲨鱼在离开 2 号摄像机后约 31 分钟回到了 1 号摄像机。两台摄像机之间的距离为436 m，鲨鱼的平均地速和水速均为0。-1，分别与格陵兰鲨鱼的相当小头昏睡症（0.22–0.34 毫秒-1) 在调整大小的鱼类中表现出最慢的比较游泳速度。太平洋睡鲨的环境水温为 5.3°C，远高于格陵兰鲨鱼（~2°C）。如此低的游泳速度可以用“视觉相互作用假说”来解释，但这并不是冷水对其运动器官产生负面影响的结果。