Tropical river systems support some of the most productive inland fisheries around the world, but their fisheries are being placed under growing pressure from disruptions to connectivity caused by river developments. Fish passage measures and complementary monitoring techniques are needed to mitigate the barrier impacts of river developments and validate the effectiveness of such measures, respectively. Passive integrated transponder (PIT) systems have been shown to be effective for monitoring the effectiveness of fish passage measures in temperate river systems but remain largely untested in tropical systems. The aim of this study was to investigate the suitability of four wild-caught tropical species from the Mekong River (Hypsibarbus lagleri, Hemibagrus filamentus, Barbonymus schwanenfeldii, and Scaphognathops bandanensis) to PIT tagging. This was achieved by undertaking PIT tag retention experiments in outdoor tanks onsite, to assess whether PIT tags can be retained in these species without impacting their survival and body condition. We found that there was no significant impact of PIT tagging on mortality; no fish lost condition from tagging; and the overall tag rejection rate was very low (4.5%) in all four species. The study findings indicate that H. lagleri, H. filamentus, B. schwanenfeldii, and S. bandanensis are all suitable for being PIT tagged in tropical river systems, and therefore could potentially be used to assess various fish passage metrics such as approach, attraction and passage efficiency.

热带河流系统支持着世界上一些生产力最高的内陆渔业，但由于河流开发造成的连通性中断，其渔业正面临着越来越大的压力。需要鱼道措施和补充监测技术来分别减轻河流开发的障碍影响并验证这些措施的有效性。无源集成转发器（PIT）系统已被证明可以有效地监测温带河流系统中鱼类通过措施的有效性，但在热带系统中基本上尚未经过测试。本研究的目的是调查湄公河四种野生捕获的热带物种（Hypsibarbus lagleri、Hemibagrusfilamentus、Barbonymus schwanenfeldii 和 Scaphognathops bandanensis）对 PIT 标记的适用性。这是通过在现场室外水箱中进行 PIT 标签保留实验来实现的，以评估 PIT 标签是否可以保留在这些物种中而不影响其生存和身体状况。我们发现 PIT 标签对死亡率没有显着影响；没有鱼因标记而失去状态；所有四个物种的总体标签拒绝率都非常低（4.5%）。研究结果表明，H. lagleri、H.filamentus、B.schwanenfeldii 和 S.bandanensis都适合在热带河流系统中进行 PIT 标记，因此可能用于评估各种鱼类通过指标，例如接近、吸引力和通过效率。