Spatial distribution and thermal regime of habitation of two representatives of the genus Lycodes (Perciformes: Zoarcidae) in Russian waters of the Sea of Japan.

Main features of spatial distribution and thermal regime of habitation of Lycodes nakamurae and L. yamatoi in Russian waters of the Sea of Japan are discussed. Comparative analysis of specific features of distribution of eelpouts of the mesobenthal group ( L. nakamurae, L. yamatoi, L. tanakae) in some areas of the Sea of Japan with different hydrological conditions is provided. No horizontal migrations directed along isobaths were revealed in these species. In Russian waters of the Sea of Japan, L. nakamurae inhabits depths 130-760 m, preferring the range of depths 200-700 m (it was found in catches of 95.7% of trawlings); L. yamatai inhabits depths 140-800 m, but most frequently is found in the range of depths 200-500 m (86.1% of trawlings). L. nakamurae occurs at a temperature of 0.4-1.2°C and L. yamatoi is found at 0.3-1.9°C. Seasonal migrational activity in the former species is more pronounced than in the latter. Spring-summer migration towards the shelf for feeding and reproduction and autumn-winter wintering migration towards the continental slope taking place with the cooling of the shelf are noticeable. Maximum range of vertical migrations is typical of medium-size fish and minimal is typical of juveniles of the studied species that inhabit the upper section of the bathyal (200-400 m). It is suggested that the lower limit of distribution of eelpouts of the mesobenthal group in the southern and northern sectors of the Sea of Japan coincide. The upper boundary of habitation of the species in different seasons of the year is totally determined by the thermal regime of water masses in different areas of the sea. [ABSTRACT FROM AUTHOR]