Some newspapers report that the difference of spawning seasons between himemasu and kunimasu was the decisive factor which led to the miraculous discovery of the "extinct" fish, kunimasu.
In recent years, fishermen at Lake Saiko had been seeing fish with "black body, " so they called the fish “kuromasu," or a black trout. The fishemen had believed that it was the same as himemasu (a relative species to kunimasu) discolored after the spawning season.
In spring, the same fish were brought to the university research group and studied. What they have found was astonishing evidence: the tails were damaged. This brought out a question if it was really a himemasu, because its spawning season is in autumn -- not in spring. In April, Professor Nakabou of Kyoto University visited Lake Saiko and finally confirmed his doubt.
A Kunimasu Specimen Recovered at Lake Saiko
(Courtesy of Kyoto University)
Kyoto University preserves 9 of the 17 kunimasu specimens that exist in the world. In March, Sakanakun, a popular TV talent and a professor at a marine science university, had brought two fish specimens, which astonished Professor Nakabou. The features – black body, shapes of gills, and digestive organs – matched with those of kunimasu.
Although himemasu, relative fish abundantly found in Lake Saiko, are said to darken its color after the spawning season, Professor Nakabou was skeptical about this. His research group had obtained some "kuromasu" specimens from the local fishermen.
The "black" himemasu had some odd elements for himemasu: First, some female fish were holding eggs --there was no way himemasu would spawn in March and April; secondly, they were caught in a depth of 30-40 meters, which was too deep for himemasu to lay eggs; Lastly, the fish were washed up on the shore after spawning, which is a known as a unique behavior of kunimasu.
Professor Nakabou was assured after a genetic analogy. He submitted a thesis to the Ichthyology Society of Japan in late October. After a thorough screening by the experts, the report was permitted to be published in the society’s English paper.
Specimen registered as a new-found species in 1925.
(Courtesy of The Field Museum in Chicago, USA)
Despite all the validation, Professor Nakabou was still concerned about one thing: light spots on around the dorsal fin.
In the 1925 report by Dr.Jordan, an American Ichthyologist, which registedred kunimasu as a new-found species, it is stated as “no dark spots on body or fins.” This report has been considered as the most valuable ground to certify a kunimasu on.
Professor Hideki Sugiyama of Akita Prefectural University, author of the acclaimed book Kunimasu Hyakka, stresses that the presence of dark spots does not agree with the report, so that it is questionable whether or not it is kunimasu indeed.
In another report, however, made in 1941 by Dr. Oshima, who studied under Jordan, reported that “light dark spots are seen near the dorsal fins," which is why Professor Nakabou concludes that “individual differences could cause dark spots on some, so that we cannot we cannot jump to a conclusion that it is not kunimasu. If all the other traits match, it must be it. “
Kunimasu and himemasu both belong to a family of land-locked red salmon. They are hard to distinguish from each other because both can be traced back to the same origin. Not much is known about kunimasu because it was driven to the verge of extinction before it was studied and documented. Ministry of the Environment is revewing the registration status in its Red List, and the involved community seem to continue a heated discussion.