Lake Ikeda - Ikedako

Located in the southeastern part of the Satsuma Peninsula in Kagoshima Prefecture, this is the largest lake in Kyushu. It has an area of ​​10.91 square kilometers, a circumference of 15 kilometers, a water surface elevation of 66 meters, and a maximum depth of 233 meters. It is a caldera lake, and its transparency was once measured at 26.8 meters (1929), one of the world's best, but in recent years it has fluctuated between 4 and 15 meters. In the southeastern part of the lake, there is a dome indicating a water depth of 42 meters below the surface, which is said to be a sub-lake volcanic cone that formed after the formation of the main lake and is very rare. There are no rivers flowing into the lake. The water temperature is around 10°C all year round, even at the depths, and it is classified as a tropical lake. Originally classified as an oligotrophic lake with low production, the lake was released and farmed with carp, eels, smelt, and sweetfish from around 1930, and many plants and animals have begun to grow there. The giant eel is particularly famous, with some reaching a body length of 2 meters. It is part of Kirishima-Kinkowan National Park and is popular with tourists. It is a 30-minute bus ride from Ibusuki Station. It is also close to the starting point of the Ibusuki Skyline.

[Kimihiko Tsukada]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

鹿児島県薩摩半島(さつまはんとう)南東部に位置する九州最大の湖。面積10.91平方キロメートル、周囲15キロメートル、水面標高66メートル、最大深度233メートル。カルデラ湖で透明度はかつて26.8メートル（1929）と測定され世界有数の値を示していたが、近年は4～15メートルで推移。湖の南東部分には、水面下42メートルの水深を示す円頂丘が存在し、本湖形成後に生じた湖底火山丘といわれ、たいへん珍しい。流入河川はない。水温は深層でも1年中10℃前後で、湖沼分類上熱帯湖に属している。本来は貧栄養湖に分類され生産量の少ない湖であったが、1930年（昭和5）ごろから、コイ、ウナギ、ワカサギ、アユなどの放流、養殖が行われ、多くの動植物が生育するようになった。なかでもオオウナギは体長2メートルに達するものもあり有名。霧島錦江湾(きりしまきんこうわん)国立公園の一部をなし観光客も多い。指宿(いぶすき)駅からバス30分。指宿スカイラインの基点にも近い。

［塚田公彦］

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