Kim Beom-Sik, Kang Chang-Keun, Jung Hae Kun, Park Hyun Je, Park Jong Won, Kim Ju Kyoung, Lee Chung Il
Department of Marine Ecology and Environment, Gangneung-Wonju National University, Gangneung, 25457, Republic of Korea.
Department of Environment and Energy Engineering, Gwangju Institute of Science and Technology, Gwangju, 61005, Republic of Korea.
Sci Rep. 2025 Apr 16;15(1):13117. doi: 10.1038/s41598-025-97890-8.
Korea's northeastern coastal waters (NECWs) represent the southwestern range of chum salmon (Oncorhynchus keta), spanning temperate and boreal zones. However, understanding their migration to the NECWs in association with environmental changes remains challenging. Using tagging and tracking techniques, we studied salmon migration behavior and timing during spawning in ascending rivers. When sea levels rose, resulting in a decrease in sea surface temperature, salmon exhibited active vertical movement through the water column and migrated to the surface layer. The number of salmon ascending rivers between early October and early December increased when the sea surface temperature decreased below 18 °C, peaking when the water column was mixed during spring tides, and decreased when sea surface temperature dropped below 14 °C. In rivers, salmon favored gravelly riverbeds over sand/silt substrates, stayed in deep and shaded areas during the day, and advanced upstream at night. Our findings emphasize that water temperature and tidal elevation are key factors affecting salmon distribution in coastal waters and the timing of river entry. Riverbed composition, water depth, and photoperiod also influenced migration speed and timing in rivers. This research enhances our understanding of salmon behavior during spawning in the NECWs and adjacent rivers at their southern limits.
韩国东北沿海水域（NECWs）是大麻哈鱼（Oncorhynchus keta）分布范围的西南边界，跨越温带和寒带地区。然而，了解它们与环境变化相关的向NECWs的洄游情况仍然具有挑战性。我们利用标记和追踪技术，研究了大麻哈鱼在溯河产卵期间的洄游行为和时间。当海平面上升导致海面温度下降时，大麻哈鱼会在水柱中进行活跃的垂直移动并迁移到表层。当海面温度降至18°C以下时，10月初至12月初溯河的大麻哈鱼数量增加，在大潮期间水柱混合时达到峰值，而当海面温度降至14°C以下时数量减少。在河流中，大麻哈鱼更喜欢砾石河床而非沙质/粉质基质，白天停留在深水区和阴凉处，夜间向上游前进。我们的研究结果强调，水温与潮汐高度是影响大麻哈鱼在沿海水域分布及进入河流时间的关键因素。河床组成、水深和光周期也会影响大麻哈鱼在河流中的洄游速度和时间。这项研究增进了我们对NECWs及其南部边界附近河流中大麻哈鱼产卵期间行为的理解。
