Overview of the fish fauna of the Chaunskaya basin – the area of the natural reserve "Chaunskaya Guba" and the port of Pevek (East Siberian Arctic)

The fishes of the Chaunskaya Bay and its Basin have been little studied. Part of the coast of this vast Arctic estuary (about 9 thousand km2) is included in the state nature reserve “Chaunskaya Guba”; at the entrance to the bay there is the seaport of Pevek, a transit hub of the Northern Sea Route. The area has been identified as one of the priorities for the protection of biodiversity in the seas of the Russian Arctic. Solving the problem of biota conservation begins with an inventory of the fauna. The paper presents the results of summarizing data on the species composition of marine, anadromous and freshwater fishes in the Chaunskaya Bay and its basin. The updated list includes 36 species of 28 genera, 16 families and 10 orders. In marine waters there are 31 species (18 marine, 13 anadromous and semi-anadromous fish), in rivers and lakes there are 5 freshwater (and 13 anadromous and semi-anadromous) species. The Muksun Coregonus muksun (Pallas, 1814) and the pike Esox lucius Linnaeus, 1758, which were absent in the fauna lists, are added. The lamprey Lethenteron kessleri (Anikin, 1905), the Pacific herring Clupea pallasii Valenciennes, 1847, and the Arctic charr Salvelinus alpinus (Linnaeus, 1758), which were previously recorded, are not confirmed by reliable findings. The marine fish community of the Chaunskaya Bay is an impoverished shelf fauna of the East Siberian Sea and includes species adapted to desalination. The freshwater ichthyofauna of the basin differs from the fauna of the neighboring Kolyma River region in the loss of a number of freshwater species, which are believed to have been extinct because of the Holocene cooling. A significant part of the fish complex consists of elements of the North Pacific fauna that spread to the East Siberian Sea in the postglacial period.