Current State and Development factors of Northern Gannet (<i>Morus Bassanus</i>, Sulidae, Aves) colonies in the Russian Sector of the Barents Sea

Abstract

Based on the results of long-term observations, the colonization of the islands of the Murmansk coast, Barents Sea by northern gannets (Morus bassanus (L. 1758)) is described. The formation of colonies on the Murman Islands is shown to be associated with the restoration of the stocks of juvenile Atlantic herring in the Barents Sea in the 1990’s to the 2000’s along with an intense influx of birds from the Norwegian part of the species’ range. The population dynamics of the species in two Russian colonies are also analyzed. The end of the previous and the beginning of this decade were marked by an abrupt increase in population numbers in both Russian colonies. To date, the general distribution area of this species includes the southern part of the Barents Sea and the entire water area of the White Sea; the eastern border of its nesting distribution area being restricted to Kharlov Island, eastern Murman in the Barents Sea. Starting with 2022, the population dynamics in the westernmost Russian colony have been determined by mortality caused by the HPAIV avian influenza epidemic, this threatening further development of both Russian colonies. In the summer of 2023, using the phenotypic indicator of the previous infection, the number of sick birds in the colony was determined as amounting to 13–15% of the total number of individuals nesting there.