Invasive Species in Korea

The following presentation materials were put together by Kyeong-jin, Mi-yeon, Hyeon-geun and Dae-han for their final exam in PowerPoint format on the topic of environment. The presentation is not published here in its entirety but it is published with their permission. Thank, guys, for doing such a phenomenal job and for allowing me to post this!

Invasive Species in Korea

What is an invasive species? It is a non-native specie of flora or fauna that has been introduced willfully or accidentally by human, bird or animal, or blown in by storm or other natural phenomena. Often invasive species, when transported unwittingly, are brought in via seeds by birds or in the fur of migrating animals. The invasive species might just survive, but when they thrive in the non-native environment, usually they do so without major competitors ... and that is when they become a problem.

two common non-native species in Korea:
American bull frog and the largemouth bass

Shipping activities are likely the biggest form of introduction of non-native species to new areas. Barnacles or algae can attach itself to bottoms of vessels, but most likely the vessels transport new species via the ballast waters the vessels take on in "location A" and dump in "location B".

Fish stocking, the raising of fish in a confined area and releasing them in lakes, rivers and streams, is a willful, yet perhaps unwitting, way of introducing invasive species. The introduced fish are supposed to repopulate diminished bodies of water; however, they often have no natural enemies, therefore changing the fauna, thriving and often placing the native species at risk.

The presentation team looked at 6 of the most frequently talked about animal species that are non-native to Korea but causing a radical shift in the natural environment, almost always because the species thrive in the new environment (agreeable temperature, suitable habitat, etc).

(1) American Bull Frog (in Korea since 1958)

(2) Largemouth Bass (in Korea since 1973)

(3) Red-eared Strider Turtle (in Korea since the 1970s)

(4) Asian Predatory Wasp (in Korea since 2003)

The wasp was introduced to Pusan via ship and have found city-living to be ideal circumstances for a new home. Because of Korea becoming sub-tropical, the wasps have a found a "perfect" new habitat. According to the presenters, every day in Pusan the 119 rescue team removes 50 wasp hives!

(5) Nutria (in Korea since 1985)

The Nutria were originally introduced to Korea for a cheap fur and for providing meat protein. Early on they were farmed, however, either they escaped or were illegally released as now they pose a serious threat to the environment where they have no natural predators. They thrive most happily in swamp lands and dark, humid places. The Nakdong River area and Cheju Island see the largest thriving masses, and since they have become such pests, the government has placed a W20,000 bounty on each Nutria killed and exterminated.

(6) Jellyfish (appearing in Korea waters most noticeably since 2000)

With global warming and the increase in the water temperatures particularly along the southern coasts, jellyfish have appeared in ever-increasing numbers. Jellyfish have natural enemies, but since humans have done extensive over-fishing and are depleting the oceans of these natural aggressors, jellyfish are thriving, especially as they love the expanding warming ocean.

Basically, these six non-native species are thriving in their new environments. In most cases they are destroying the natural habitat and therefore threatening native species. In regard to the American Bull Frog, the Nutria and the Largemouth Bass specifically, they are demolishing the food chain. The Nutria particularly copiously eat insects and small vertebras from ponds, swamps and marshlands, sweeping the area of the diverse kinds of insect and smaller animals on the food chain. In short, they are destroying the balance of the ecosystem.

Humans, therefore, need to be educated on the fragile environment in which they live, and in the event of trying to rehabilitate a failing ecosystem, do more research on the reception and long-term effect of the introduction of a non-native specie.