Tragedy of the Commons

Since the early 1900s, people have used dams to retain water and create hydro power.  While these uses undoubtedly help people who live near and around the dam, the effect on salmon is far less pleasant.  The dams disrupt and increase the amount of times they migrate.  Those who do make it past the dam, are often stunned by the electric turbines they have to pass through.  Many people have tried to solve the problem, including creating hatcheries, but all attempts have been unsuccessful.