A newly developed soft-type turtle releasing device (Soft-TRD) for setnet fisheries
A newly developed soft-type turtle releasing device (Soft-TRD) for setnet fisheries
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新开发的用于定网渔业的软式海龟释放装置（Soft-TRD）
DOI：
10.1016/j.aaf.2020.06.011
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发表时间：
2021
影响因子：
--
通讯作者：
Hirai Y.
中科院分区：
文献类型：
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作者：
Shiode D;Shiozawa M;Hu F;Tokai T;Hirai Y.
本研究研究了一种新开发的用于固定网的软式海龟释放装置（Soft-TRD）。一些固定网鱼室（袋网）在海面敞开，而另一些则是封闭的（带有天花板网）并淹没在水中。误入水下袋网的海龟经常会被淹死，因为天花板网阻止它们游到水面呼吸。 Soft-TRD 在 2 m × 2 m 网的中心有一个狭缝，用作逃生出口。由于狭缝两端附有浮子的浮力，逃逸狭缝保持关闭，并防止鱼逃出。海龟可以向上推动逃生缝，从而打开并允许海龟逃脱。为了确定 Soft-TRD 的最佳设计，在室外水箱中进行了海龟放生试验。试验中使用了四只红海龟 (Caretta caretta)（标准甲壳长度 (SCL)：67.1–72.8 cm）和五只绿海龟 (Chelonia mydas)（SCL：42.4–63.4 cm）。将一只海龟放入实验袋网中，并在天花板中央部分安装 Soft-TRD（共 6 个型号），观察其行为。所有海龟都成功逃离模型，逃生缝长度为 150 厘米，叠加宽度为 10 厘米，两端各有一个 4 公斤力的浮力。海龟逃走后，逃生缝立即关闭。还使用浸没袋网（30×10×10m）进行了两个月的海上试验（同一型号）。大约 90%（八只中的七只）被困的红海龟通过 Soft-TRD 成功逃脱。该装置的引入并没有中断捕鱼活动。 Soft-TRD的使用将有助于将海龟从渔网中释放出来，并为海龟保护工作做出贡献。
This study investigated a newly developed soft-type turtle releasing device (Soft-TRD) for setnets. Some setnet fish chambers (bag nets) are open at the sea surface, while others are closed (with ceiling netting) and submerged. Sea turtles that stray into submerged bag nets often drown because the ceiling netting prevents them from swimming up to the surface to breathe. The Soft-TRD has a slit that functions as an escape outlet at the center of a 2 m × 2 m netting. The escape slit remains closed, due to the buoyancy of a float attached at each end of the slit, and prevents fish from getting out. Turtles can push the escape slit upward, which opens and allows the turtles to escape. To decide the optimum design of the Soft-TRD, a turtle releasing trial was conducted in an outdoor water tank. Four loggerhead turtles (Caretta caretta) (standard carapace length (SCL): 67.1–72.8 cm) and five green turtles (Chelonia mydas) (SCL: 42.4–63.4 cm) were used for the trial. A single turtle was placed into the experimental bag net where the Soft-TRD (six models in total) was mounted at the center part of the ceiling, and its behavior was observed. All turtles successfully escaped the model with a 150 cm length escape slit, 10 cm overlaying width, and a 4 kgf buoyancy float at each end. The escape slit immediately closed after the turtles escaped. A sea trial (same model) was also performed using a submerged bag net (30 × 10 × 10 m) for two months. Approximately 90% (seven of the eight) of the entrapped loggerhead turtles successfully escaped out through the Soft-TRD. Fishing was not interrupted by the introduction of this device. The use of the Soft-TRD would be helpful in releasing sea turtles from the setnets and contribute to sea turtle conservation efforts.