1、Catadromous fish are those that spend most of their lives in freshwater but migrate to the ocean to spawn.
下降性鱼类是指大部分生活在淡水中，但迁移到海洋产卵的鱼类。
2、Eels are an example of catadromous fish, with their larvae hatching in the ocean and then migrating upstream to freshwater rivers.
鳗鱼是下降性鱼类的一个例子，它们的幼虫在海洋中孵化，然后向上游迁移到淡水河流。