Japan Atlas: Nature 
Marimo and Lake Akan

Location: Akan Town, Hokkaido 
Area: 13 sq km (5 sq mi) 
Circumference: 25.9 km (16.1 miles) 
Elevation: 420 m (1378 ft) 
Maximum depth: 45 m (148 ft) 

Designated on December 4, 1934 
Area: 905 sq km (349 sq mi) 
Annual Visitors: 6,590,000 (1995) 

a.k.a. Cladophora sauteri or Cladophora aegagropila 
First discovered in 1823 by Dr. Anton E. Sauter, an Austrian botanist, in Lake Zeller, Austria. 



The Rolling Green Jewels Under the Water 

The bottom of Lake Akan is inhabited by miraculously spherical algae called "marimo." Although marimo and its related species are observed in the lakes of several European countries and in some other lakes in Japan, only in Lake Akan marimo grow 20 to 30 centimeters (8 to 12 inches) in diameter and have a spherical surface that is beautifully soft and smooth like velvet.  

Marimo have not always had an easy life in the lake which serves the local community as a tourist attraction and a valuable water resource. Ironically, after the first governmental designation of marimo as a Natural Treasure in 1921, people came from all over the country to obtain these unique plants. Some were taken away as souvenirs by tourists and many others were stolen and sold for high prices in urban areas. Other damages were caused after a hydroelectric power plant was built along Akan River which flows out of the lake in 1920. A number of marimo, which can survive only in the shallow water, were exposed and withered as a result of the lowered water level due to the use of lake water for generating electricity.  

In the 1940s, recognizing that marimo was severely endangered, the local people launched a campaign to protect the plant, one of which continues to this day, the Marimo Festival which originated in 1950. Held every October, when the autumn leaves on the lakeshores are at their best, the three-day festival is led by the local Ainu people, and culminates on the third day with a ritual in which a senior Ainu on board a small wooden boat returns the marimo one by one, carefully and thankfully, into the lake.  

The local government of Akan Town re-opened the Marimo Exhibition and Observation Center in 1996 after extensive renovation. The new center is equipped with various facilities to promote the environmental and scientific importance of marimo as well as research on the protection and propagation of the species.  

Photos: Lake Akan in summer and winter (above); velvety marimo in the water (below). (Hokkaido Tourist Association). 

Unauthorized reproduction of the photos in this page is prohibited. 

Related Links:


Web Japan