'Extinct' trout species rediscovered

The Yomiuri Shimbun

Kunimasu trout

Kunimasu trout--long believed to have become extinct more than 60 years ago--have been found in Saiko lake in Yamanashi Prefecture, according to research conducted by Kyoto University Prof. Tetsuji Nakabo and TV personality Masayuki Miyazawa, who is widely known by the professional moniker Sakana-kun (Mr. Fish).

The trout, scientifically named oncorhynchus nerka kawamurae and originally known to inhabit only Lake Tazawa, the nation's deepest lake, in Akita Prefecture, has been designated as extinct by the Environment Ministry. The freshwater fish were last seen in Lake Tazawa in 1948.

The trout's environment in the lake was severely damaged by the introduction of highly acidic waters from a nearby river in 1948 to increase the volume of water for hydroelectric power generation.

The discovery of the "extinct" fish came when Sakana-kun, also a guest associate professor at Tokyo University of Marine Science and Technology, found nine blackish trout among rainbow trout caught in Saiko lake. Sakana-kun, who sports a fish-shaped cap when appearing on TV programs, asked his acquaintance Nakabo to examine the unusual fish. Nakabo and his Kyoto University team confirmed the fish as kunimasu trout by analyzing their DNA.

Nakabo said the nine kunimasu trout were descendants of those hatched in Saiko lake from about 100,000 eggs brought from Lake Tazawa in 1935.

The Environment Ministry plans to remove kunimasu trout from the list of extinct species when it reviews the list in fiscal 2012.

It will be the first time for the ministry to remove a vertebrate species from the list. Shellfish and fungi have been removed in the past.

"We should take this opportunity to think about the value of nature and living creatures, so as not to send any species to extinction," Sakana-kun said.

According to a fisheries cooperative association at Saiko lake, kunimasu trout have sometimes been caught there during net fishing for lake smelts. Fishermen in Saiko call the trout "black trout" because the color of their skin is blackish when compared with rainbow trout.

Yamanashi Prefectural Gov. Shomei Yokouchi said: "I am very surprised to hear that [kunimasu trout] were found in Saiko lake. I'll take steps to conserve them in consultation with the Environment Ministry."