Behavioural characteristics of loggerhead turtles (Caretta caretta) in a submerged bag net of a setnet observed in a bycatch simulation and the development of a turtle releasing device
Behavioural characteristics of loggerhead turtles (Caretta caretta) in a submerged bag net of a setnet observed in a bycatch simulation and the development of a turtle releasing device
复制标题
兼捕模拟中观察到的红海龟（Caretta caretta）在定置网的水下袋网中的行为特征以及海龟释放装置的开发
DOI：
10.1002/aqc.3201
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Tokai T.
中科院分区：
文献类型：
--
作者：
Shiozawa M;Shiode D;Okuyama J;Hu F; Tokai T.
一种放龟装置(TRD)可以降低网箱副渔获物的死亡率。进入被淹没的网袋网的海龟反复地将它们的头顶向天花板网(这里指的是俯卧撑)，以努力上升呼吸。为了帮助海龟成功逃离围网，了解海龟的俯卧撑行为是至关重要的，因为海龟需要到达TRD并打开襟门。本研究的目的是弄清楚海龟何时开始做俯卧撑，这些俯卧撑是如何变化的，以及在模拟兼捕的情况下，哪些因素会影响俯卧撑。使用深度、温度和三轴加速度数据记录仪和摄像机来确定海龟的垂直运动、环境温度、活动水平和鳍拍频率(FBF)。在日本三叶县，用30米×10米×10米的袋网对5只亚成体斑龟(Caretta Aretta)进行了10-30分钟的10次试验。每次试验开始后，海龟开始做俯卧撑5.1秒±33.3分钟。在记录的35%的上升阶段中，FBF随着时间的推移而增加，并且在随后的俯卧撑中的活动水平显著高于其他俯卧撑。每一系列俯卧撑的活动水平随着时间的推移而增加，但最早从第一次俯卧撑后的9.8分钟开始下降。因此，TRD的设计应该使海龟能够在大约10分钟内逃脱。单个序列中的俯卧撑数量、活动水平和FBF受到水温的影响。因此，需要根据不同的季节和地区改变TRD翻板门的关闭力。
A turtle releasing device (TRD) can reduce the mortality of bycatch in setnets. Turtles that have entered the submerged bag net of setnets repeatedly push their heads up against the ceiling net (referred to here as a push‐up) in an effort to ascend to breathe. To aid the successful escape of turtles from the setnet, it is essential to understand the turtle's push‐up behaviour, as they need to reach the TRD and open its flap door.The objectives of this study were to clarify when turtles start to perform push‐ups, how these push‐ups change, and what factors affect push‐ups under the simulated condition of bycatch. A depth, temperature, and tri‐axial acceleration data logger and a video camera were employed to determine vertical movement, ambient temperature, the level of activity, and flipper beat frequency (FBF) of the turtles. Ten trials of 10–30 minutes for five subadult loggerhead turtles (Caretta caretta) were conducted using a submerged bag net (30 × 10 × 10 m) of a setnet in Mie Prefecture, Japan.Turtles started to perform push‐ups 5.1 ± 3.3 minutes after the start of each trial. FBF increased as more time elapsed in 35% of ascent phases recorded, and the level of activity during the following push‐ups was significantly higher than during other push‐ups. The level of activity in each sequence of push‐ups increased as more time elapsed; however, it started to decrease from 9.8 minutes after the first push‐up at the earliest. Therefore, the TRD should be designed to enable turtles to escape within approximately 10 minutes.The number of push‐ups in a single sequence, the activity level, and FBF were affected by water temperature. Therefore, the closing force of the TRD flap door needs to be changed according to the different seasons and regions.