Size-selective mortality occurs in smolts during a seaward migration, but not in river residents, in masu salmon (Oncorhynchus masou)
Size-selective mortality occurs in smolts during a seaward migration, but not in river residents, in masu salmon (Oncorhynchus masou)
复制标题
DOI：
10.1007/s10641-022-01213-z
复制
发表时间：
2022-01-17
影响因子：
1.4
通讯作者：
Kishida, Osamu
中科院分区：
文献类型：
--
作者：
Futamura, Ryo;Morita, Kentaro;Kishida, Osamu
鲑科鱼在顺流而下时经常经历大小选择性死亡（即，向海迁移）。然而，目前还不清楚大小选择性死亡率是否特定于这种生活史（即，移民），或由替代生活史共享（即，居民）。在这项研究中，我们调查了马苏鲑鱼（Oncorhynchus masou）移民和居民在迁移期间（即，4月至6月）在日本北方的Horonai河。通过使用PIT标签和天线进行基于个人的研究，我们发现，较大的移民更有可能生存的向海迁移比较小的移民，但在同一时期的河流居民没有检测到大小依赖的生存。这些结果表明，大小选择性死亡率是特定的河下游移民在马苏鲑鱼向海迁移期间。我们将这一发现归因于食鱼鱼类的存在（例如，褐鳟鱼（萨尔莫trutta），它们占据了洄游通道，并以洄游的马苏鲑鱼为食，而这种食鱼性鱼类不会出现在居民居住的上游河段。
Salmonid fish often experience size-selective mortality when descending the river (i.e., seaward migration). However, it is unknown whether size-selective mortality is specific to this life history (i.e., migrants), or is shared by an alternative life history (i.e., residents). In this study, we investigated the size-dependent mortality patterns of masu salmon (Oncorhynchus masou) migrants and residents during the migration period (i.e., April to June) in the Horonai River, northern Japan. By conducting an individual-based study using PIT tags and antennas, we show that larger migrants more likely survived the seaward migration than smaller migrants, but size-dependent survival was not detected in river residents during the same period. These results suggest that size-selective mortality is specific to the river-descending migrants in masu salmon in their seaward migration period. We attribute this finding to the presence of piscivorous fishes (e.g., brown trout Salmo trutta) which occupy the migration corridor and consume masu salmon migrants, whereas such piscivorous fish do not occur in the river section farther upstream inhabited by residents.