About a month ago in Korea, there was news in the media that three Piranhas and one Red Pacu were found in one of the lakes in Korea. Those fishes are known to be living in Amazon River in South America and the news was a definitely shock to almost everyone in Korea. The local government eventually decided to dry up the lake to find out any remaining alien species in order to avoid any potential ecosystem disturbance. Luckily there was no more Piranhas or Pacus discovered in the lake after three days' pumping all the water out of the lake. Local government guessed someone in the local area just carelessly abandoned such Amazonian fish into the late. Although such Amazonian fishes are not designated as invasive alien species by Korea Environmental Ministry because they are simply categorized as aquarium fishes, the news was shocking enough to make people very concerned about the current and potential alien species in our ecosystem.

One of the famous alien species animals in Korea are Bull Frog which originally came from America and Bass which is also easily found in North America. Most of such alien species are designated as invasive alien species when there is no higher level predator or natural enemy in the related ecosystem. Bull Frog was brought into Korea in mid-1970s for edible purposes as well as income source for farm family business. After a few years, however, due to dramatic increase of the number of Bull Frogs, breeders' carelessness and severe flood, etc. such alien frogs were put to the local ecosystem and sat at the top of the food chain. After being designated as an invasive alien species by Korea Environmental Ministry, many environmental groups and people tried to revive the original shape of our nature and although it is not completely cleared, the number of Bull Frog gradually decreases up until now.

On the other hand, Bass that was brought into Korea in 1970s for edible purpose, has still made problems in the ecosystem because Bass has very strong viability and eats native species in Korea such as minnow, carp, salmon and sweetfish. Many local governments now conduct campaigns and host certain activities to decrease the number of Bass or prevent Bass breeding. For example, city of Ulsan is planning to host a nation-wide fishing competition for Bass and certain NGO group does research about removal of Bass eggs and prevention of hatching. Despite all the efforts, complete removal of such invasive alien species is very challenging and still remains a long-term job to get done.

Of course it is very hard to predict the impact and risks for more than 30 years of the future, but we should recognize the importance of the disturbance of the ecosystem in any local nature and be extremely careful in brining alien species into other regions.

Reference: http://www.nie.re.kr/main/, http://www.eco-c.or.kr/default/index.php