Present condition and conservation of snails and their parasitic cercariae on tidal flats in west Pacific region

在日本约60个地点检查了生活在潮滩上的蜗牛及其寄生的幼虫吸虫。各滩涂的钉螺分布情况不同，但在名护市（奄美大岛）的嘉贝滩涂和大浦河口、北九州市的曾根滩涂和佐贺县的多取河口，钉螺的分布非常高。在滨松市汤户町发现的卡明巴氏杆菌、陆津市上泽发现的多形B、西表岛浦内川发现的带纹蟹实蝇和香川县多木川发现的裂冠蟹实蝇的感染率较高，在汤户町、和歌山市若川和浦内川发现的尾蚴多样性最高（5种）。计算了代表钉螺和尾蚴多样性和稀有性的指数，特别是在嘉贝潮滩、浦内川和大浦川获得了较高的值。因此，人们认为这些地方是最有价值的h 关于我们 他们认为，淡水吸虫是最重要的保护对象。在泰国，在大约100个地点检查了螺和尾蚴，在东部海岸的Ban Klong Klaeng的Cingulata中记录了最高的感染率100%。两种虫态的总感染率基本相同，但在两种虫态共存的生境中，两种虫态的感染率往往较高。在普吉镇的红树林研究和发展站，尾蚴多样性最高。此外，我们在印度洋海啸前后的三个地点进行了调查，但没有发现感染率和尾蚴区系的显着变化。在韩国，在7个地点检查了蜗牛和尾蚴。新万金潮滩三角帆蚌B.cumingii的感染率很高，是咸性吸虫的重要栖息地。然而，潮滩被堤岸和蜗牛封闭，它们的寄生虫死亡。在妙多群岛，Yeosu-shi，螺类多样性高，但吸虫感染率很低。少

Snails living on tidal flats and their parasitic larval trematodes were examined at about 60 sites in Japan. Snail diversities varied from tidal flats, but very high at Gabei tidal flat and estuary of Oura River in Nago city (Amami-Oshima Island), Sone tidal flat in Kitakyushu city and estuary of Takori River in Saga Pref. Seventeen kinds of cercariae were found from all snails examined. Infection rates of cercariae were very high in Batillaria cumingii at Yuuto-cho in Hamamatsu city, in B.multiformis at Jougasawa in Mutsu city, in Cerithidea cingulata at Urauchi River of Iriomote Island and C.rizophorarum at Doki River in Kagawa Pref. Highest diversity (5 species) of cercariae were recorded in Yuuto-cho, Waka River in Wakayama city and Urauchi River. Indices representing diversity and rarity of snails and cercariae were calculated and especially high values were obtained at Gabei tidal flat, Urauchi River and Oura River. Consequently it is thought that those places are most valuable h … More abitats for brackish water trematodes and that they are the most important candidates for conservation. In Thailand, snails and cercariae were examined at about 100 sites and the highest infection rate 100% was recorded in C.cingulata at Ban Klong Klaeng in eastern coast. Total infection rates of C.cingulata were almost the same as those of C.djadjariensis, but in coexisting sites infection rate of one species was often higher than the other. Cercaria diversity was highest at Mangrove Research and Development Station in Phuket town. Moreover we conducted the survey at three sites before and after the Indian Ocean tsunami, but the significant changes in infection rates and cercarial fauna were not detected. In Korea snails and cercariae were examined at seven sites. Infection rates in B.cumingii in Saemangeum tidal flat was very high and thought to be a valuable place for brackish trematodes. However, the tidal flat was closed by banks and snails and their parasites died out. In Myodo Is., Yeosu-shi, diversity of snails was high, but their infection rate to trematodes was very low. Less