Fish discovered in a remote 4-mile stretch of stream in Russia is a new species
Researchers have discovered a new fish species found nowhere else in the world except a 3- to 4-mile stretch of stream in a remote region of southern Russia.
Phoxinus ayukensis is a “super narrow-ranged” species of minnow discovered in the Ayuk stream in the karstic region of the Northwestern Caucasus, according to a study published June 25 in the journal Zoosystematics and Evolution.
Waterfalls further up Ayuk stream act as natural barriers, limiting the new species’ range, according to researchers.
In addition to precipitation, the Ayuk stream is also fed, in part, by subterranean streams. During the summer, when precipitation is low, surface flow stops, and the stream nearly dries completely, water pools in the deepest parts of the riverbed where the new species rides out the drought conditions.
Researchers said the Ayuk minnow may not exist elsewhere because it is “too adapted to cold waters.” The Ayuk stream maintains “stable low temperatures,” and the new species may be not be able to survive in warmer waters, the study said.
The species, about 2 inches long, on average, is described as being “olive-yellow-green in color with very little contrast” between horizontal and vertical patterning, according to the study.
Researchers said the name of the Ayuk Stream comes from the Adyghe word “ayuko”, which means “unfriendly valley.”
According to the study, “low genetic diversity coupled with extremely limited range within the seasonally half-drying stream” calls for a high level of protection for the Ayuk minnow.
The research team included Oleg N. Artaev, Ilya S. Turbanov, Aleksey A. Bolotovskiy, Alexander A. Gandlin and Boris A. Levin.
This story was originally published June 26, 2025 at 5:57 PM with the headline "Fish discovered in a remote 4-mile stretch of stream in Russia is a new species."
