Molluscs in the Ubolratana Reservoir, Khon Kaen

บทคัดย่อ

The study was conducted six times between 1999 and 2000. Five stations were chosen covering all areas of the Ubolratana Reservoir. There were 15 families and 69 species of molluscs with Melanoides tuberculata as the dominant species. The highest density was the Family Thiaridae at 47 – 76 % annually, and the rarest was Family Hydrobiidae. Maximum numbers of mollusc were found in front of the reservoir station. At the depth of 0.5 to 2.0 meters molluscs were widely distributed. The population varies gradually throughout the year but decreased noticeably in December. The fishing operation and animal migration were the main cause of mollusc quantity dropping.