Photo/IllutrationSome of the trout artificially bred in Yamanashi Prefecture (Hiroshi Kawai)

FUJI-KAWAGUCHIKO, Yamanashi Prefecture--A freshwater trout species thought to be extinct for about 70 years is finally returning to its original habitat in northern Japan after being discovered in a lake almost 1,000 kilometers away.

The kunimasu (Oncorhynchus kawamurae) was found in Lake Saiko here in 2010 and has been referred to as a "miracle fish."

Ten fish are now going back to where the species is thought to have originated--Lake Tazawako in Akita Prefecture. They will be displayed in a museum aquarium from July 1.

“This is a long-awaited homecoming,” said Toshihiro Oyama, 56, a senior official of the Senboku city government that will receive the rare species, which has been listed as extinct in the wild by the Environment Ministry.

“Nowadays, people who know that kunimasu used to inhabit Lake Tazawako are limited to those aged 85 or older. I want as many residents as possible to see kunimasu,” said Oyama.

The 10 kunimasu were reared at the Yamanashi Fisheries Technology Center Oshino Branch, and left for Akita Prefecture on May 9.

The deep-water trout will be on display at Tazawako Kunimasu Miraikan, a museum adjacent to Lake Tazawako. Yamanashi Prefecture loaned the fish to Akita Prefecture without setting a deadline for their return.

“I am grateful that we can respond to the expectations of residents of Akita Prefecture who are eagerly waiting for the kunimasu's return,” said Takumi Okazaki, 49, head of the Oshino branch.

The kunimasu, an indigenous species of Lake Tazawako, died out in the lake due to strongly acidic river water drawn into the lake as part of hydropower generation and agricultural water projects in the prewar period.

However, kunimasu eggs were sent from Lake Tazawako to other lakes, including Lake Saiko near Mount Fuji, from the 1920s to the 1930s.