Lake Akan

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Lake Akan
The view from Mount Oakan (July 2008)
LocationKushiro, Hokkaidō, Japan
Coordinates43°27′6″N 144°5′55″E / 43.45167°N 144.09861°E / 43.45167; 144.09861Coordinates: 43°27′6″N 144°5′55″E / 43.45167°N 144.09861°E / 43.45167; 144.09861
Lake typeDimictic
Native name阿寒湖
Primary outflowsAkan River
Catchment area148 km2 (57 sq mi)
Basin countriesJapan
Surface area13 km2 (3,200 acres)
Average depth17.8 m (58 ft)
Max. depth44.8 m (147 ft)
Water volume0.23 km3 (0.055 cu mi)
Shore length125.9 km (16.1 mi)
Surface elevation420 m (1,380 ft)
FrozenDecember to April
Islands4: Ōjima, Kojima, Yaitai Island, Chūrui Island
Official nameAkan-ko
Designated8 November 2005
Reference no.1540[1]
1 Shore length is not a well-defined measure.
Akan Caldera
Lake Akan (center)
Mount Meakan (bottom left)
Mount Oakan (center right)
Lake Akan and Mount Oakan

Lake Akan (阿寒湖, Akan-ko) is a lake in Kushiro, Hokkaidō, Japan. It is located in Akan National Park and is a Ramsar Site.[2][3]


Volcanic activity formed the lake some 6,000 years ago, when a dam was formed. The lake used to have a clarity of 8–9 meters in the 1930s. Pollution from local hotspring resorts has decreased the transparency to 3–4 meters.[4]

Flora and fauna[edit]

The lake is famous for the marimo (Aegagropila linnaei), aggregations of algae that form into spherical shapes 2–30 cm in diameter. Other flora of the lake include the following:[4]

Kokanee salmon (Oncorhynchus nerka) are native to Lake Akan. Other fauna of the lake include the following:[4]

See also[edit]


  1. ^ "Akan-ko". Ramsar Sites Information Service. Retrieved 25 April 2018.
  2. ^ "Data Summary: Akan-ko (Lake Akan)". World Lakes Database. International Lake Environment Committee. Archived from the original on 2012-04-20. Retrieved 2009-05-18.
  3. ^ "Ramsar Sites in Japan - Akan-ko" (PDF). Ministry of the Environment. Retrieved 24 March 2011.
  4. ^ a b c "AKAN-KO (LAKE AKAN)". World Lakes Database. International Lake Environment Committee. Archived from the original on 2012-03-05. Retrieved 2009-05-18.