Notes on the fishes of the Severnaya Zemlya archipelago and the spawning area of polar cod Boreogadus saida (Gadidae)

Abstract

Data on the fishes of the high-latitude Severnaya Zemlya archipelago (the North Land) is presented. The archipelago is located in the Arctic on the border between the Kara Sea and the Laptev Sea. The ichthyofauna of the archipelago has not been studied; therefore, even small collections are of interest. Fish samples were obtained during the expedition “Open Ocean: Arctic Archipelagos – 2019: Severnaya Zemlya”. In addition, the samples from this area in the collections of the Zoological Institute (ZIN) were studied, which have been received from polar expeditions to the Kara and Laptev seas during the entire era of polar research. The most significant fact is the discovery of mass accumulation of polar cod Boreogadus saida (Lepechin, 1774) larvae in Mikoyan Bay (Bolshevik Island), which gives evidence of important spawning grounds near Severnaya Zemlya. Indirect evidence of this can be found in the publications of polar explorers who overwintered on Severnaya Zemlya in the 1930s–1950s and have reported that the polar cod approaches the shores for spawning in August, in huge schools. The waters of Severnaya Zemlya represent the spawning area of polar cod in the central part of the Eurasian shelf, which is not mentioned in current literature. In addition to polar cod, a few more species are registered in samples from the coastal waters of the archipelago (depths to 38 m), rough hookear sculpin Artediellus scaber Knipowitsch, 1907, twohorn sculpin Icelus bicornis (Reinhardt, 1840) (family Cottidae), Liparis tunicatus Reinhardt, 1836, black-bellied snailfish L. cf. fabricii (Liparidae), Knipowich eelpout Gymnelus knipowitschi Chernova, 1999 (Zoarcidae) and three-spined stickleback Gasterosteus aculeatus (Linnaeus, 1758) (Gasterosteidae). In the deepwater straits, snailfish Careproctus sp. (174–234 m) and pale eelpout Lycodes pallidus Collett, 1879 (105–348 m) were found. The Arctic charr Salvelinus alpinus (Linnaeus, 1758) (Salmonidae) inhabits some lakes of the archipelago. This is the first finding of a three-spined stickleback in the east of the Kara Sea.

Species Composition, Abundance, Distribution Features and Size Characteristics of Fish of the Genus Liparis (Cottiformes: Liparidae) in the East-Siberian and Laptev Seas

“…In Greenland waters, gelatinous snailfish was recorded at depths of 5-1460 m (Møller et al, 2010). It was caught in coastal waters of the Severnaya Zemlya archipelago by divers at depths of 7-20 m (Chernova et al, 2021). Reports on the finding of gelatinous snailfish at a depth of 1880 m (Kirillov et al, 2016) are doubtful, since it is suggested that it was caught in the pelagic zone above the indicated depth (Able, 1990;Mecklenburg et al, 2018).…”

“…Liparis tunicatus is the most shallow-water species of the genus in the Arctic seas. It is found almost from the surface, 0 m (Møller et al, 2010) and shallow waters, 7-13 m (Chernova et al, 2021) to a depth of 620 m (Coad and Reist, 2004), but it rarely occurs deeper than 150 m (Parin et al, 2014). In the Laptev Sea and the East Siberian Sea, it was recorded in the depth ranges of 10-94 and 12-54 m, respectively.…”

Population divergence manifested by genomic rearrangements in a keystone Arctic species with high gene flow

“…These results corroborate previous studies conducted on smaller sets of nuclear as well as mitochondrial markers, showing low levels of spatial population structure among polar cod sampled at a relatively large spatial scale 28,36 as well as in the Barents Sea and Arctic Ocean region 26,29 . Based on two hypothesized spawning grounds in the Barents Sea, i.e., in the northwestern Barents Sea and southeastern Barents Sea area [23][24][25] , our findings suggest that natal homing behavior is unlikely to be prominent, and rather indicates that there is high connectivity between different locations and/or sub-populations within the Barents Sea area.…”

“…Despite its central role in the ecosystem, linking higher and lower trophic levels [21][22][23] , in-depth knowledge of its biology, migratory behavior, population structuring, and genomic composition in general is limited. For the Barents Sea area, previous studies have suggested that there are likely two spawning grounds, one in the Northwest of the Barents Sea and one in the southeast Barents Sea, adjacent to Novaya Zemlya [23][24][25] , Russia, suggesting that there could be at least two or more sub-populations within this region. Several studies have been carried out to characterize the population structure of polar cod throughout their circumpolar occurrence, most of which have utilized only a handful to hundreds of genetic markers, and the results have been inconsistent [26][27][28][29] .…”