On the 16th, Otsu City’s certified NPO “Biwako Trust” has a planarian “Bdellocephala”, which is endangered on the Red List of the Ministry of the Environment, off the lake Imazu (Takashima City, Shiga Prefecture). ) Announced that about 80 animals were found in July this year. It may have decreased due to an increase in water temperature and a decrease in oxygen concentration at the bottom of the lake.
According to Michio Kumagai, a professor at Ritsumeikan University, the secretary general of the corporation, Bdellocephala inhabits the bottom of a lake with a depth of more than 40 meters and a low water temperature. Larger ones are about 5 cm long. When surveyed at a nearby location in 2008, the average per square meter was 3.0, but this time it was 0.46.