Complete mitochondrial genome of <I>Clupeonella abrau</I> (Maliatsky, 1930) (Clupeiformes), an endemic species of freshwater fish from lake Abrau (Russia)

The Abrau sprat (Tyulka or Sardelka) Clupeonella abrau (Maliatsky, 1930) is an endemic fish of Lake Abrau (Krasnodar Territory). The full mitogenome of C. abrau (16650 bp in length, with a conservative gene arrangement for Clupeidae) demonstrates 98.8% similarity with the mitogenome of a related species, the Black Sea-Caspian tulka (C. cultriventris) from the Black Sea. The sequence of the COX1 gene was also studied in a museum specimen collected in Lake Abrau in 1938. Variability in modern Abrau sprat COX1 locus in about 0.15%, the difference between C. abrau and C. cultriventris is 1.2%, and the difference between the Museum and modern samples of tulka from Lake Abrau is 0.92%. It has been confirmed that the Abrau sprat is present in the fish community and capable of reproducing in the lake. Various alternative scenarios for the settlement of Lake Abrau have been proposed.