Horizontal and vertical migration behavior of silver-phase Japanese eels in coastal, pelagic and spawning areas observed by pop-up satellite archival tags
Horizontal and vertical migration behavior of silver-phase Japanese eels in coastal, pelagic and spawning areas observed by pop-up satellite archival tags
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DOI：
10.1016/j.jembe.2021.151587
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发表时间：
2021-06-17
影响因子：
2
通讯作者：
Tsukamoto, Katsumi
中科院分区：
文献类型：
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作者：
Higuchi, Takatoshi;Watanabe, Shun;Tsukamoto, Katsumi
弹出式卫星档案标签(PSAT)被用来研究包括日本鳗鱼在内的几种鳗鱼在公海上神秘的产卵迁徙。为了比较日本鳗鱼在产卵迁徙的各个地理区域的迁徙行为，用PSATS对7条银鳗(852-992 cm，1095-1809g)在日本东部、小川群岛以南及其产卵区的游泳行为进行了跟踪。从日本沿海释放的三条鳗鱼向东或东南迁徙，可能包括黑潮在产卵迁徙的初始阶段进行的一些运输。从日本海岸放生的一条鳗鱼在穿过黑潮延伸部向东流动的不同侧的弯道和不同水团时，改变了游泳深度。在小川群岛以西放生的一条鳗鱼大部分向南移动，从放生地点向产卵区移动，在产卵区放生的一条鳗鱼表现出非常稳定的食饵垂直迁徙(DVM)。在跟踪周期的9-47天(14-69天)中，5条鳗鱼表现出稳定的DVM(60.0-72.1%)，另外2条鳗鱼表现出异常行为。昼夜浅/温水(12.0~535.2 m/12.5~24.5℃)和白天较深/较冷水(593.0~941.0 m/4.5~9.5℃)之间的昼夜节律变化。5条鳗鱼的游泳深度与月龄、月亮高度、太阳高度呈正相关。无论深度如何，鳗鱼在这三个地区的白天最低水温几乎相同(5.7+/-0.98摄氏度)，这表明它们在达到大约5摄氏度的温度时停止下降。上升和下降分别发生在日落和黄昏前后以及黎明和日出之间。三条鳗鱼在黎明时分(5：05-6：35)在119.5米、59米和423.5米深处被捕食者摄食，此时鳗鱼开始进入DVM的体面阶段。根据记录的气温迅速上升，估计潜在的捕食者是具有保温能力的鱼类，如金枪鱼和旗鱼。这项研究表明，日本鳗鱼在产卵迁徙过程中可能会使用类似的DVM行为，无论它们在哪里或环境条件下，游泳深度都是由光和热环境决定的。这些行为可能是避免捕食的关键。
Pop-up satellite archival tags (PSAT) have been used to study the mysterious open ocean spawning migrations of several anguillid eel species including the Japanese eel, Anguilla japonica. To compare migration behaviors of Japanese eels in each general geographic region of their spawning migration, 7 silver eels (852-992 cm, 1095-1809 g) were tracked with PSATs and their swimming behaviors in regions of east of Japan, south of the Ogasawara Islands, and in their spawning area was analyzed. Three eels released from coastal Japan migrated east or southeastward, likely including some transport by the Kuroshio in the initial phase of the spawning migration. An eel released from the coast of Japan changed swimming depths as it crossed meanders and different water masses on different sides of the eastward flow of the Kuroshio Extension. An eel released west of the Ogasawara Islands moved mostly southward from the release site toward the spawning area where an eel released in the spawning area showed very stable diel vertical migrations (DVM). Five eels showed stable DVM for 9-47 days (60.0-72.1%) of the tracking periods (14-69 days), and 2 other eels showed abnormal behaviors. The daily rhythms of DVM behavior transitioned between shallower/warmer water at night (12.0-535.2 m/12.5-24.5 degrees C) and deeper/colder water during daytime (593.0-941.0 m/4.5-9.5 degrees C). The swimming depths of 5 eels had positive correlations with lunar age, moon altitude and sun altitude. Eels experienced almost the same daytime minimum water temperature (5.7 +/- 0.98 degrees C) in the 3 areas regardless of depth, suggesting that they stop descending when they reach a temperature of approximately 5 degrees C. The ascending and descending occurred between around sunset and dusk, and dawn and sunrise, respectively. Three eels were ingested by predators near dawn (5:05-6:35) at depths of 119.5, 59, and 423.5 m when the eels start the decent phase of their DVM. Potential predators were estimated to be fish that have heat conservation ability such as tuna and swordfish based on rapid increases in recorded temperature. This study suggests that Japanese eels probably use similar DVM behaviors regardless of the location or environmental conditions during their spawning migration and that the swimming depths are determined by light and thermal environments. These behaviors are likely essential for predation avoidance.