Benthic harpacticoid copepods of the Yenisei Gulf and the adjacent shallow waters of the Kara Sea

Abstract

ABSTRACTThe harpacticoid fauna was studied at 16 stations in the Yenisei Gulf (the Kara Sea) and the adjacent shallow-water open-sea area. The total harpacticoid abundance was relatively low (an average of 64.4 individuals/10 cm2). Thirty-three species (including putative species) from 13 families were recorded; the Ameiridae, Miraciidae and Pseudotachidiidae were the most diverse families. Most of the species identified were new for the Kara Sea, several were found for the first time after their original description, and seven forms were presumably new to science. The updated list of the Kara Sea harpacticoids has twice as many species in common with the White and Barents Seas than with the eastern Arctic/northern Pacific seas, presumably indicating the asymmetry in the Trans-Arctic fauna exchange. Species diversity increased significantly with increasing distance from the freshwater section seawards. Four assemblages were distinguished based on their taxonomic composition, one in the riverine part and three seaward. Canonical correspondence analysis indicated the salinity, depth, type of sediments and chlorophyll a content in the water column as the main factors affecting the community structure. By contrast with macrofauna, harpacticoid distribution in the Yenisei Gulf did not show a wide transition area with predominance of brackish-water forms. The harpacticoid fauna of the Kara Sea is most likely not impoverished compared with other Arctic seas, but it is greatly under-explored and remains a ‘blank spot’ in this respect.