Dataset originated from field surveys carried out from May to October 2001, to assess the seasonal variations in the population structure of four species of intertidal harpacticoids (Paraleptastacus kliei, Huntemannia jadensis, Heterolaophonte minuta, and Stenhelia palustris) at three sites in the middle intertidal zone of Chernorechenskaya Bay (White Sea) with different sediment compositions.