Lakes and Marshes of the National Park
History
The Akan area is a caldera (large volcanic crater) volcano that formed as a result of volcanic activity from Mt. Fuppushi, Mt. Furebetsu, Mt. Meakan, and Mt. Oakan. Many lakes, ponds, and marshes dot the area and support an array of flora and fauna.
There are approximately ten lakes of varying size around Mt. Oakan. Originally, these lakes were joined as one enormous lake referred to as Old Lake Akan. Eruptions from Mt. Oakan between 10,000 and 6,000 years ago caused the old lake to be partially filled in, giving rise to the separate lakes that remain today.
Features of Lakes and Marshes in the Akan Region
Lake Akan is the region’s most well-known body of water. The lake is the natural habitat of Marimo, a rare spherical algae, and kokanee salmon, a saltwater fish that is also adapted to fresh water. The nutrients that seep into the lake from the surrounding forests are one reason these unusual forms of life thrive here. The lake’s water level remains stable year-round due to the forest’s natural ability to regulate seasonal water flow. Lake Panketo and Lake Penketo, the next two largest lakes, are located deep in the forests of Mt. Oakan’s northeastern foothills. Aside from these three large lakes, there are also the smaller water bodies of Lake Taro, Lake Jiro, and the Hyotan Swamp. Despite originating from the same source, all of these lakes have varying levels of water quality.
In contrast to the lakes around Mt. Oakan, Lake Onneto was formed after an eruption from Mt. Meakan created a dam. The cobalt-blue waters of the lake changes to different shades of green and blue depending on the weather, time of day, and the watcher’s viewpoint, which is why it is one of Hokkaido’s “Three Mysterious Lakes.”
