Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand.
Research Center in Bioresources for Agriculture, Industry and Medicine, Chiang Mai University, Chiang Mai, Thailand.
PLoS One. 2022 May 10;17(5):e0267667. doi: 10.1371/journal.pone.0267667. eCollection 2022.
Capture-based aquaculture is now gaining much attention in Southeast Asia. This system was used to produce several fish species with social and economic implications, including the giant snakehead (Channa micropeltes). As wild harvesting of organisms for seed stock is one of main practices in capture-based aquaculture, abundance and distribution of the wild stock are essential for both environmental impact evaluation and stock management. Mark and recapture, visual observation and physical capture of target species are costly, ineffective, and labour intensive for fish surveys in several cases. Detection of target organisms using eDNA (environmental DNA) could be a good alternative as it has proved to be a non-invasive, rapid, and sensitive method for aquatic species monitoring and surveying. Here, we developed a TaqMan assay that targets the 16S region of giant snakehead DNA to amplify eDNA captured in water samples. 300 µl of water samples were collected from 15 sites located in the Chao Phraya River Basin (Ping, Wang, Yom, Nan, and Chao Phraya River) and filtered with 0.7 µm glass fibre membrane filter. Giant snakehead eDNA was detected in most tributaries (60%) with concentrations ranging from 74.0 copies/ml in Wang River sites to 7.4 copies/ml in Nan River sites. As intensification of capture-based aquaculture could lead to depleting of wild fish stocks, urgent management is needed. However, the existing conventional approaches for assessment of fish overexploitation, survey and monitoring have several limitations.
基于捕捞的水产养殖现在在东南亚得到了广泛关注。该系统被用于生产具有社会和经济意义的几种鱼类，包括巨骨舌鱼（Channa micropeltes）。由于野生生物采集作为种子库存的主要实践之一在基于捕捞的水产养殖中，野生种群的丰度和分布对于环境影响评估和种群管理都是必不可少的。在许多情况下，标记和重捕、目标物种的视觉观察和物理捕获对于鱼类调查来说都是昂贵、低效和劳动密集型的。使用 eDNA（环境 DNA）检测目标生物可能是一个很好的选择，因为它已被证明是一种非侵入性、快速和敏感的水生物种监测和调查方法。在这里，我们开发了一种 TaqMan 测定法，该方法针对巨骨舌鱼 DNA 的 16S 区域，以扩增水样中捕获的 eDNA。从位于湄公河流域（屏、汪、约、喃和湄公河）的 15 个地点采集了 300 µl 的水样，并使用 0.7 µm 玻璃纤维膜过滤器进行过滤。在大多数支流（60%）中检测到巨骨舌鱼的 eDNA，浓度范围从汪河的 74.0 个拷贝/ml 到喃河的 7.4 个拷贝/ml。由于基于捕捞的水产养殖的集约化可能导致野生鱼类资源枯竭，因此需要紧急管理。然而，现有的评估鱼类过度捕捞、调查和监测的常规方法存在一些局限性。
