Kunimasu, An 'Extinct' Fish, Rediscovered !

Breaking News:

Kunimasu, "extinct" fish that existed only in Lake Tazawa  have been rediscovered in Lake Saiko of Yamanashi Prefecture. This really caught us by surprise: it overturned the previous belief that the fish had long died out!

The news first arrived yesterday evening. TBS Japanese TV station has reported and it soon spread nationwide! Asahi Shinbun （朝日新聞）has reported it this morning as the front page news as follows:

The Asahi Shinbun: Kunimasu, endemic species to Japan that has been listed on Red List (Red Data Book) of Japanese Ministry of the Environment (MOE), has been found in a lake in Yamanashi Prefecture. A scientific research group of Kyoto University has just announced as verified. 70 years have passed since the species have last seen alive. This is the first time “extinct species” on the national Red List have been rediscovered. Ministry of the Environment has announced that it will review the list.

Kunimasu (Onchorhynchus nerka kawamurae) is originally was endemic species to Lake Tazawa which is said to become as large as 30 cm and had been fished by the locals as a food source. After the channel construction in 1940s that caused influx of acid water to the lake, the fish are said to have been extinguished. It was believed to have been wiped out of the world.

Kunimasu Found in Lake Saiko

Kunimasu have been found alive in Lake Saiko, one of the fuji-goko (five lakes near Mt. Fuji) in Yamanashi Prefecture. Nine samples of so-called “kuromasu,” caught by the local fishery industry union workers in March to April earlier this year, were examined by the University research group.

Professor Nakabou of Kyoto University

Not only the dark body color but also the branchial structure and forms of digestive organs have been identified as kunimasu. Its breeding season in January to March has been matched with that of kunimasu. Genetic analogy has shown that the kunimasu is different from himemasu found in the same lake; thus the rediscovered have never intercrossed with the latter. The study is expected to be published in a peer-reviewed scientific journal.

 

Back in February, Professor Nakabou has requested his friend Sakanakun, a popular TV talent who pursue his professional knowledge as a marine biologist and a visiting guest professor at Tokyo University of Marine Science and Technology, to make a lively illustration of the extinct species. To get an inspiration, Sakanakun has ordered a sample of himemasu, related species, from Lake Saiko; instead, he was sent a darker fish – which turned out to be a kunimasu.

The record shows five years before the species have died out in Lake Tazawa, 100,000 eggs have been transported to Lake Saiko. That is how the fish is said to have survived.

Sakanakun

In Lake Saiko, fish with darker bodies that resemble himemasu existed and called “kuromasu”. The locals had believed that was darker variation of himemasu.

According to Red List of Ministry of the Environment, there are four species designated as Japanese endemic species: Kunimasu, Minamitomiyo, Suwamoroko, and Chozame. Professor Nakabou says, “Lake Saiko has a relatively low water temperature, which was probably a suitable condition for himemasu.” Ministry of the Environment states such cases, in which species designated as ‘extinct’ have rediscovered, have happened in fields of plants and fungi but this is the first case in fish.

There are only 20 kunimasu samples in the world. Kunimasu has become popular as “maboroshi-no-sakana” (nonexistent fish). In 1990s, Tazawako-machi Tourism Association had posted cash reward of 5,000,000 yen but it was never found.