Salmon and the river ecosystem have become threatened by a host of problems originating far up river.

三文鱼和河流生态系统已经受到来自河流上游的一系列问题的威胁。

Then, officials can make changes based on how the river ecosystem is changing.

然后，官员们可以根据河流生态系统的变化情况做出改变。

Joelle has been fishing on the Nile for decades, but industrial waste dumped into the water is having a devastating effect on the river's ecosystem.

乔尔几十年来一直在尼罗河上捕鱼，但倾倒在水中的工业废物对尼罗河的生态系统造成了毁灭性影响。

John Hamill, a volunteer with the organization Trout Unlimited, says the experiments will help explain the current situation of all the different river resources. Then, officials can make changes based on how the river ecosystem is changing.

约翰·哈米尔是" 鳟鱼无限" 组织的一名志愿者，他说借助过去的经验，可以解释所有河流资源的现状。然后，官员可以根据河流生态系统的改变做出相应的调整。