Fujikoto and Kasuge Rivers
The Fujikoto and Kasuge Rivers descend through the pristine mountain forests of Shirakami Sanchi—an area known for the softness and purity of its waters—before meeting in the town of Fujisato. South of Fujisato, the rivers’ combined flow enters the Yoneshiro River, which empties into the Sea of Japan.
The 56.5-kilometer Fujikoto River originates on Mt. Fujisato-Komagatake (1,158 m), a peak just outside the Shirakami Sanchi World Natural Heritage area. Numerous small tributaries flow into the Fujikoto as it makes its way through Daira Gorge and down to the flatlands of Fujisato. The Fujikoto was once used by foresters to float logs downstream, until train tracks were built to bring timber down from the mountains.
The 36-kilometer Kasuge River flows down from the slopes of Mt. Futatsumori (1,086 m), a peak that lies within the buffer zone of the Shirakami Sanchi World Natural Heritage Site. The Kasuge is the only river in Akita with a drainage basin that lies entirely within the Heritage Site’s protected core zone. The river once flowed unobstructed into town, but the construction of Subari Dam in 1970 flooded the narrow valley through which it ran and created Lake Subari. A campground, picnic area, and restaurant now line the lake’s southeastern shore.
Because of their excellent water quality and unrestricted access to the ocean, the Fujikoto and Kasuge are famous for their sweetfish (Plecoglossus altivelis), known as ayu. Ayu are migratory, and in autumn travel downriver to lay their eggs close to the sea. When ayu fry hatch, they swim to the ocean to live for several months before swimming back upstream in spring. However, damns prevent this migration, and rivers that can support ayu are becoming scarcer. Although the Subari Dam restricts ayu to the lower reaches of the Kasuge, both rivers support ayu populations.
In addition to ayu, the Fujikoto and Kasuge are famous for char (iwana) and cherry trout (yamame). On the Kasuge, fishing is limited to areas downriver of Subari Dam. Fishing permits are required for both rivers, and can be obtained at fishing supply outlets and other shops around Fujisato.
The rivers are also locations for “river trekking,” a warm-weather activity in which hikers traverse a gorge by walking along the bed of a river. River trekkers follow in the footsteps of local residents who once used rivers and streams to traverse Shirakami Sanchi forests due to the lack of footpaths.