How does over-exploitation of beneficial species affect biodiversity?Explain with the help of one example

Humans have always depended on nature for food and shelter, but when need turns to ‘greed’, it leads to over-exploitation of natural resources.Many species extinctions in the last 500 years(Steller’s sea cow,passenger pigeon) were due to over-exploitation by humans.
Presently,many marine fish populations around the world are ever harvested, endangering the continued existence of some commercially important species.