fish climbing a waterfall
Refers to fish, especially salmon or trout, swimming up a waterfall during migration. Often used in seasonal or nature contexts.
秋になると、鮭の滝登りが見られる。
In autumn, you can see salmon climbing the waterfall.
Kana spelling is common in everyday writing, especially when the kanji 滝 is not needed.
Compound of 滝 (waterfall) and 登り (climbing), from the verb 登る (to climb).