Deep-benthic rajid skates represent an important component of bottom ichthyofauna of the western North Pacific. In some areas they comprise up to 10% of fish biomass. Skates play significant role in food webs, consuming variety of fish and invertebrates including commercially important species. Russian fishery for skates in the northwestern Pacific is poorly developed due to lack of domestic demand. Though skates are very promising target of inshore fisheries with export to Asian fish markets. Their fishery should be based on intimate knowledge of their ecology and biology, which are still poorly understood even for most common species inhabited the northwestern Pacific. The data on some ecological parameters and biological features of seven most abundant and common species (Aleutian skate Bathyraja aleutica, whiteblotched skate B. maculata, Matsubara skate B. matsubarai, whitebrow skate B. minispinosa, Alaska skate B. parmifera, Okhotsk skate B. violacea, and mud skate Rhinoraja taranetzi) were sampled in the Pacific waters off the northern Kuril Islands and southeastern Kamchatka (47°50’N-52°10’N, depth range 85-850 m) during 1992-2002 bottom trawl surveys and commercial fishing operations. The spatial and vertical distributions are presented, bottom temperature preferences are shown, and dynamics of relative abundance are considered. Data on length frequencies, length-weight relationships, and sex ratios in different size classes are presented. Data on sexual dimorphism in skate sizes are given as well. The study of vertical ontogenetic shifts of skate species considered was attempted.