What is one of the most damaging issues in freshwater systems that has caused the highest number of declines in fish?

Question

Quizplus · Accepted Answer

Dams have caused significant declines in fish populations in freshwater systems by obstructing migration routes and changing water flows, temperatures, and sediment levels. Pollution, climate change, and ozone depletion can also have detrimental effects on freshwater ecosystems and fish populations, but they may not be the primary cause of the highest number of declines.

What Is One of the Most Damaging Issues in Freshwater