Answer:
By blocking fish migration
Explanation:
By releasing toxic chemicals in their emissions
Hydroelectrics only emissions are usually, non harmful electromagnetic signals.
By generating Significant heat that artificially warms nearby water
Possible, but they do not produce much significant heat
By producing greenhouse gases
No, just no- its magnets that are water moved, no room for greenhouse gasses..
By blocking fish migration
It is a dam, blocking a river, with fish in it.
