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

对生活在潮滩上的蜗牛及其寄生的吸虫幼虫在日本约60个地点进行了检查。钉螺多样性因滩涂不同而不同，但名护市嘎北滩涂、大岛岛欧拉河河口、北九州岛Sone滩涂和佐贺县高科里河河口钉螺多样性较高。从所有受检钉螺中检出17种尾蚴。日本滨松市鱼藤町的小球虫、木津市朱加泽的多形巴第鞭毛虫、伊里奥莫特岛浦口河的环沟棘尾线虫和香川县多基河的里佐波罗线虫的尾蚴感染率都很高。后藤町、和歌山市和卡河、浦内河的尾蚴多样性最高(5种)。计算了反映钉螺和尾蚴多样性和稀有度的指数，其中以嘎北滩涂、乌拉河和乌拉河的多样性和稀有度指数最高。因此，那些地方被认为是最有价值的h…更多的咸水吸虫，它们是保护的最重要的候选者。在泰国，对大约100个地点的钉螺和尾虫进行了检查，东海岸班克朗的带状线虫感染率最高，为100%。两种线虫的总感染率基本相同，但在共存地点，一种线虫的感染率往往高于另一种。普吉岛红树林研究开发站尾虫多样性最高。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动物的显著变化。在韩国，对七个地点的蜗牛和尾蚴进行了检查。Saemangeum潮滩的枯枝杆菌感染率很高，被认为是微咸水吸虫的宝贵栖息地。然而，潮滩被河岸和蜗牛关闭，它们的寄生虫灭绝了。丽水市Myodo is.钉螺多样性较高，但对吸虫的感染率很低。较少

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