Yury Dyldin, a scientist at the Biological Institute of TSU, is studying the species composition of fish in the waters of Sakhalin Island. According to the latest observations, tetraodontiform fishes, including the thermophilic fugu species, which traditionally have inhabited the more southerly seas of Korea and Japan, have begun to appear more and more often in the temperate waters washing the largest island of Russia. In the process of his studying them, a new species was described by Keiichi Matsuura and named the fine patterned puffer.
– In a sense, these discoveries turned out to be random, - says Yury Dyldin. - It all began with the contact from the head of the Anivsky department of ichthyology of the Sakhalinrybvod enterprise, Sergey Makeev. Knowing that I was studying the fish fauna of Sakhalin, he gave me a fugu caught in the summertime in Aniva Bay to identify the fish. None of the local fishermen had seen such specimens.
For more information, the biologist asked his colleagues from the Zoological Museum of the Russian Academy of Sciences to take measurements and photos of fugu that had been caught at different times in the waters off Sakhalin and stored at the Institute. After studying the photographs and archival materials on Sakhalin and the entire Far Eastern region, including adjacent Japan, for the last hundred years, the scientist sought professional advice from Keiichi Matsuura, one of the most well known and respected specialists in the world to study this group of fish and the curator of the ichthyological collection of the National Museum of Nature and Science in Tokyo.
In the joint study of the individual caught in the Aniva Bay near the mouth of the Lyutoga River, scientists concluded that it belonged to the species yellowfin puffer. There is no evidence of the presence of this species in the waters of Sakhalin earlier.
- But the most unexpected result of the research was not even this, - says Yury Dyldin. - A careful analysis of photographs of two fugu specimens collected off Sakhalin in the middle of the twentieth century showed that these specimens were mistakenly attributed to another species under the general name Takifugu niphobles. In fact, the fugu caught on Sakhalin, as it turned out, belonged to T. poecilonotus, and after an additional revision by Keiichi Matsuura, it turned out that that this was a new species, which was called a painted, or patterned, fish - Takifugu favipterus Matsuura, 2017.
The bizarre name was given because of the bright color - the body of the fish is light brown, covered with a lot of white spots, the largest of them with a diameter slightly larger than the eye. The results of joint research by Yury Dyldin and Keiichi Matsuura were published in a prestigious scientific journal, Bulletin of the National Museum of Nature and Science, Tokyo.
According to the Yury Dyldin, thermophilic migrants from the tetraodont group have been regularly observed in recent years in the waters of Sakhalin and adjacent territories. Thus, in the southern and northwestern parts of the island, a Purple puffer and a Japanese puffer were recorded, in the southern part of the Sea of Okhotsk there was a Mola mola, and in 2005 and 2011 a modest filefish was observed.
According to the researchers, this could be for two reasons: either the warm branches of the Curacao current are changing their direction and leading the tropical guests to Sakhalin, or this is facilitated by climate changes that have caused a reset of the species composition in the surface waters in the summer. For example, in the last decade, some species of cartilaginous fishes (sharks and rays), uncharacteristic for Sakhalin and traditionally inhabiting much warmer waters, began to appear off the coast of the island. A similar phenomenon, recorded in literary sources, was observed in the waters near the island in the 1940-50s.