본 연구는 우리나라에서 외래종인 왕우렁이의 분포와 확산에 있어 영향을 미친 환경 및 인위적 요소를 분석하기 위해, 국내 왕우렁이 분포지역 및 관련 사회정책적 자료를 수집하여 분석하였다. 조사된 국내 왕우렁이 서식지 중 대부분은 고도 및 경사가 낮고, 농경지 인근에 위치하고 있었다. 이러한 왕우렁이 서식지의 특성은 친환경 농업이라는 인위적 활동에 의한 왕우렁이 확산 및 분포와 관련이 있는 것으로 판단된다. 우리나라에서는 왕우렁이와 관련하여 왕우렁이 농법의 국가적 장려, 왕우렁이 농법에 대한 국가 보조금 폐지, 생물다양성법 제정 등과 같은 정책적 변화와 친환경 농산물을 중시하는 웰빙 열풍 등 다양한 정책적, 사회적 사건이 발생하였다. 본 연구에서 확인한 왕우렁이의 확산 양상은 사회적 요소 중 유기농 농산물의 재배면적과 비율, 내수면 왕우렁이 생산량과 매우 유의한 상관관계를 보여, 왕우렁이 확산에 대한 인간 활동의 영향을 보여주었다. 이미 뉴트리아, 미국선녀벌레 등 많은 외래생 물종이 우리나라로 유입되고 있는 가운데, 왕우렁이와 같이 인위적 생물 확산이 반복되지 않도록 충분한 제도적 대책 보완과 함께 외래생물에 대한 범국민적 인식 제고가 필요하다.

본 실험은 왕우렁이를 대상으로 대발생한 식물플랑크톤을 제어할 수 있는 가를 파악하기 위해 섭식율 (grazing rate, GR) 및 유기물 생산 (pseudofaeces production)을 조사하였다. 섭식 효율을 조사하기 위해 시간 (12시간), 개체크기, 개체밀도, 먹이농도 조건 등의 조건을 달리하여 실험하였다. 왕우렁이는 투입 후 2시간 후에 2.5 L. gAFDW-1h-1의 최고 GR를 보이다가 12시간까지 일정한 섭식 경향을 나타내었다. 유기물 생산량은 4시간 후에 15.3 mg AFDW-1로 가장 많은 양을 나타냈다. 서로 다른 크기조건에서 각고가 1.5 cm 미만의 섭식율 변화가 크고 6시간 후에 비슷하였으며, 중간 크기(2.5 cm)가 3.0 cm 이상인 것보다 섭식율이 높았다. 밀도가 5 indiv. L-1 에서 엽록소 α 농도감소율이 가장 높았으며, 그 외의 밀도에서는 비슷한 변화를 나타내었다. 유기물 생산 역시 밀도가 높은 실험군에서 4시간에 최대로 증가하였다. 먹이농도가 600μg L-1일 때 0.54 L. gAFDW-1h-1의 가장높은 섭식율과 유기물 생산을 나타내었다. 본 연구에서 왕우렁이뿐만 아니라 논우렁이를 이용하여 식물플랑크톤 대발생을 제어 가능함을 본 연구를 통해 확인하였지만, 이들이 배설한 유기물의 제거 및 배설물의 분해에 다른 2차 문제에 대한 철저한 연구가 필요하다.

Pomacea canaliculata (golden apple snail) as an invasive species in Asia has become a serious agricultural pest, especially in young rice, and makes significant environmental changes resulting from the depletion of macrophytes in natural wetlands. Even though various environmental factors influence to growth rate, reproduction, survival and behavior in apple snail, water temperature is one of the overwhelming effect on freshwater snails in general. In this sense, the objective of this study was to examine the changes of individual behavior in the apple snail according to the temperature changes. The snails were acclimated at 25℃, and 9 behavior categories were examined in each temperature regime (25℃ to 30℃, 2 5℃ to 20℃, and 25℃ to 15℃) for three days. Autocorrelation function (ACF) was applied to characterize the presence or absence of periodic behaviors in apple snails. The snails’ behavior in the treatment of elevated temperature were irregularly fluctuated or decayed in most behavior categories. On the other hands, in decreasing temperature from 25℃ to 15℃, the snails were nonstationary, especially in clinging behavior. The snails showed periodicity and some of them were decayed in clinging behavior in temperature changing from 25℃ to 20℃.

The golden apple snail, Pomacea canaliculata, is a freshwater snail native to tropical and subtropical South America. The species was introduced into Korea as a human food source in 1983 and was first applied as a weed control agent for the paddy fields in 1992. As the snail is well known as an environmentally friendly biological control agent for weeds, the area of cultivation in which the golden apple snail is used for biological control has been enlarged substantially each year. Currently, the species is observed in open water courses. It is possible that the snail may overwinter in these open water courses and may become a serious pest, as is already the case in many Asian countries. In this study, we determined the status of the overwintering golden apple snail based on a literature survey and investigated the potential distribution area of the snail, as a result from global warming in Korea. The potential distribution area of the overwintering golden apple snail would be enlarged under the influence of global warming; ranging from 45.5% of South Korea’s land area in the 2020s to 88.4% in the 2080s.

왕우렁이(Pomacea canaliculata)는 1983년에 식용으로 일본에서 한국으로 도입된 외래종으로서, 농업에서 벼의 직파 논의 잠재적인 해충이다. 본 연구에서는 해충화되고 있는 왕우렁이의 생육특성과 충남 및 전북지역에서의 월동생태를 구명하였고, 또한 농수로에서 수생식물과 수질에 미치는 영향을 조사하였다. 자연수로에서 조사결과를 보면 왕우렁이가 높은 밀도로 서식하는 수로에서는 왕우렁이가 서식하지 않을 경우에 많았던 검정말, 붕어마름, 개구리밥, 좀개구리밥 등의 수생식물들이 발견되지 않았다. 폐쇄형 인공수조실험에서는 왕우렁이가 수생식물들을 먹이로 섭식하면서 이들 식물들을 제거하고, 수질 지표인 EC, COD, T-N 및 T-P을 높이는 것으로 나타났다.

The golden apple snail was introduced to the Korea from Japan as a potential food for people in 1983. It is one of the pests of direct-seeded rice in korea. This study was conducted to investigate rice(Oriza sativa) consumption and the extent of damage by the golden apple snail(Pomacea canaliculata) in direct-sown paddy fields. Food consumption of the golden apple snail was highest at 30℃. When the emergence of the 1st, 3rd, and 5th leave of rice supplied food, the consumption of young(shell height 15㎜) and adult golden apple snail(over shell height 30㎜) at 30℃ were 19.0/79.8, 11.0/54.5, 5.5/18.5, and 0.0/2.0 individuals, respectively. Young rice seedings(before 5th leaves of rice) are very susceptible to golden apple snail damage because the young, tender leaves and stems favor the snail"s feeding habits. The field experiment with four treatments (0, 2, 5 and 10 individuals respectively per 10 ㎡) was carried out. The most serious yield loss was 16% from the plot with 10 adults released at emergency stage of rice.

The effect of environmental factors on the over-wintering success of the apple snail, Pomacea canaliculata, which is considered as unable to hibernate during winter climate in Korea. This study was examined to determine the location of over-wintering habitats in the agricultural water system related with weed control using the apple snail in rice paddy field in the Yeongnam district from 2003 to 2006. Over-wintering success of the apple snail was observed at Hadong, Hapchen, Sanchung, Kimhae, Milyang, Changwon, Ulsan, Busan, Gyengju, Pohang, Chilgok, Seongju, Gumi, Sangju and Youngju in Yeongnam area. And the over-wintering locations of apple snail going north year by year. Accordingly, the successful over-wintering sites observed were deep wells, water running canals and brooks not dried conditions. A special feature of this sites was that the water of this sites was not frozen during winter season.

This study was investigated the potential of ducks and fish trap for the control of golden apple snail, Pomacea canaliculata, in paddy field and water canals. The smaller size of duck (700 g) preyed snails than the bigger one (1,300 g). The consumption of two ducks was bigger under plastic house. They preyed over 90% on the second days of release. The release time of ducks was more effective at seven days after inoculation of snails than simultaneous. Duck could suppress the density of snails at any time from month after inoculation. Four ducks per 30 ㎡ could control snails in an irrigation canals. The number of attracted golden apple snail per week was 216 in big fish trap (Φ 15 ㎝) with menthol paste which for a carp.

This study was carried out to determine occurrence and damage of golden apple snail, Pomacea canaliculata on water seeding area in Jeonnam province. The density of golden apple snail maintained high until October 2003, but quickly decreased from November. They overwintered only in a portion of the water canals but could not find in dried paddy field. They reproduced from May and June in the canal water and paddy field, respectively. Feeding time of golden apple snail on rice seedlings was 235.2 seconds, feeding length of that was 8.4 ㎝. When golden apple snail fed rice seedlings, the stem remain only 2.5 ㎝ from areal part which could not recover. The more density of golden apple snail, the faster feeding rate. Density and number of eggs laid of golden apple snail after overwintering was higher on bank around of paddy field than on middle of that. The percent of shell size after over wintering was higher in small (below 25 ㎜) than big (over 36 ㎜). But in case of Boseong area, the size was reverse because the soil has soft mud. The survival rate of overwintering golden apple snail was lower than that of breeding. They did not move when the temperature changed rapidly, but the temperature increased they start to move. They dead almost below -3℃. The damage of rice by golden apple snail in the direct water seeding was 20%. In machine transplanting, rice damaged only fore-end of leaf and recovered subsequently. When golden apple snail release in direct water seeding field, the percent of damage was 5.6% in immediately release plot. The later release, the lower damage.

본 연구는 왕우렁이의 생리․생태적 특성 및 논 잡초방제를 위하여 투입된 왕우렁이들의 집단패사 원인을 구명하기 위하여 수행하였다. 1983년 국내에 도입되어 양식과 논 잡초방제를 위하여 활용되고 있는 왕우렁이의 종(species)은 연체동물문(Mollusca), 복족강(Gastropoda), 중복족목(Mesogastropoda), Ampulariidae과, Pomacea속에 속하는 Pomacea canaliculata Lamarck이다. 왕우렁이의 생리․생태적 특성조사 결과 왕우렁이 성체들이 국내에서 월동되고 있으나 왕우렁이 알로는 월동되지 못하고 있다. 수컷과 암컷의 비율은 1:1.99~2.33배로 암컷의 구성비가 높았다. 생장량은 1일에 87.7 mg이었으며, 껍질은 각고가 0.31 mm, 각경이 0.33 mm씩 자랐다. 왕우렁이의 생장은 먹이의 조건 등에 따라서 차이가 있을 수 있으며, 매우 빠른 생장량을 나타내었다. 한편, 건조에 대한 저항성은 매우 강하여 3개월까지 생존율이 약 80%에 달하였다. 왕우렁이 서식에 따른 수질에 미치는 영향을 평가한 결과 다량의 서식 밀도에서는 약간의 영향을 줄 수는 있겠으나, 잡초방제를 위하여 투입되는 밀도에서는 전혀 영향이 없었다. 논 잡초방제를 위하여 벼 이앙초기에 투입되는 왕우렁이가 2~3일이내에 일시에 집단 패사되는 직접적인 원인은 미소생물인 패충류(참씨벌레)에 의하여 발생되지 않는 것으로 판명되었다. 다만 패충류 (참씨벌레)에 의하여 패사되는 비율은 밀도에 따라 2.86%와 5.71%로 매우 미미하였고, 통계적인 유의적인 차이가 없었다. 논 잡초방제를 위하여 투입된 왕우렁이들은 벼 이앙시기가 빨라지고, 일교차가 커지면서 추운 저온의 날씨로 인하여 논의 흙속으로 들어가서 죽거나 일부는 새의 먹이가 되어 사라지기 때문에 다량이 죽은 것으로 오해되었다.

After identifying species by collecting the suspended and attached algae mat inhabiting in the slow sand-filter, Spirogyra sp., Mougeotia sp. and Closterium sp. were main green algae and Synedra sp. was diatom algae. Among them green algae Spirogyra sp. was dominant species. A result of observing the life mode of apple snail for a month after introducing into the slow sand-filter, apple snail eggs were discovered on the filter walls 2 weeks after introducing, 4 weeks later lots of eggs were observed all of the slow sand-filter walls, it means there is no problem for apple snail to live in the slow sand-filter. The observation result for algae removal potential by introduced apple snail after 2 months later, slow sand-filter where apple snail were introduced, a few algal mat were observed. On the other hand, no introduced apple snail into the slow sand-filter, lots of suspended algal mats were formed in the water and attached algal mats on the sand surface as well, these algal mat induced much of operating problems.