鲑鱼生存所需的河流由于人类的开发而很快被阻隔和污染，过去多产的鲑鱼群回游现象如今已不多见。

Salmon need rivers which are quickly blocked and fouled by human development, and the teeming runs of old are now rare.

youdao

鲑鱼生存所需的河流由于人类的开发而很快被阻隔和污染，过去多产的鲑鱼群回游现象如今已不多见。

Salmon need rivers which are quickly blocked and fouled by human development, and the teeming runs of old are now rare.

youdao