Invasive species like carp and goldfish disrupt habitats by making it harder for native species to thrive. Explore the following video to see how ecologists at Cootes Paradise in Hamilton, Ontario, have helped restore a marsh.

How massive, feral goldfish are threatening the Great Lakes ecosystem

In an aquatic ecosystem where fish live, humans also influence native fish migration routes in some of the following ways:

Creating dams, weirs, and other systems for water storage or recreational activities changes the amount of water entering and exiting the ecosystem and can remove migration paths.

A thermoelectric power station with a dam structure and flowing water in a controlled channel.
A close-up of a wooden watermill with water splashing onto its spinning wheel in a rustic setting.

Installing hydroelectric power like water turbines can hurt fish and plant species if they get stuck in the turbine.

Filling, grading, removing vegetation, building construction, and changes to water levels and drainage patterns make it harder for plants and animals to thrive.

Two engineers wearing safety vests and helmets discussing plans near a river with strong water currents.