Predators like the smallmouth bass have caused problems for the upper river's environment.

像小嘴鲈鱼这样的掠食者已经给科罗拉多河上游的环境造成了问题。

Their aim is to control smallmouth bass and other predatory fish below the dam.

他们的目标是控制葛兰峡谷大坝下面的小嘴鲈鱼和其他掠食性鱼类。

Biologists have been working there to protect native fish which are threatened by the appearance of the smallmouth bass.

生物学家一直在那里工作，以保护因小嘴鲈鱼出现而受到威胁的本地鱼类。