recurrent migration

• 回游

recurrent migration的用法和样例：

例句

1. Scientists have studied the migration of fish over long distances.
   科学家研究过鱼类远距离回游的现象。
2. Dams to be built across fish and crab migration routes shall be provided with appropriate fish passage facilities.
   在鱼蟹回游通道筑坝，要建造相应的过鱼设施。