A term usually referring to marine animals, commercial extinction is the depletion of a population of species to the point where fisherman cannot catch enough of them to earn profit. It precedes the state of total extinction where the species no longer exists. The Atlantic codfish, for example, was once a staple food item in Boston but is now considered by experts to be commercially extinct. The species of fish can still be found, but already in limited numbers due to years of overfishing.