The bluegill can be identified by its blue or black "ear" markings. |
Japan's Emperor Akihito said that he was responsible for bringing the nonnative bluegill fish (Lepomis macrochirus) to Japan in the 1960s. The bluegill fish has since infested lakes and rivers across Japan, damaging the ecosystem and drastically reducing the number of some native fish.
Several bluegill were given to Akihito as a present from the then Mayor of Chicago. The bluegill is the state fish of Illinois.
Akihito said he had hoped the bluegill could be raised for food during a time of protein shortages in Japan.
Bluegill were released in Lake Biwa, Japan's largest lake, in the hope that they could be used for food and fishing. Akihito said he was distressed that the attempt to provide food had resulted in a threat to native species.
Japanese officials have done several things to combat the population explosion of the bluegill fish, including trying to increase the country's consumption of bluegill.
The number of bluegill fish peaked in 2002 at 50 million, and an extermination campaign has since halved that number, officials said.
Akihito has asked marine biology experts to help protect Japan's native species, so no more are threatened by the bluegill fish.