The spring ichthyoplankton of pacific water off northern Kuril Islands

The aim of the work is assesment of the species composition and spatial distribution of spring ichthyoplankton in area off northern Kuril Islands.Material and methods. It is based on the data of ichthyoplankton sampling in 2011, 2015 and 2016 yrs, trawl surveys in 2011 and 2015, and hydrological surveys in 2015 and 2016 yrs. Maps of the fish distribution at various stages of ontogenesis were made. Cluster analysis was used to identify the structure of ichthyoplankton  in the 2015 collections.Novelty. For the first time, data on ichthyoplankton collected by the SakhNIRO in the 2010s near the northern Kuril Islands are presented. The ichthyoplankton complexes of the spring 2015 are identified and their spatial location is shown.Results. Eggs and larvae of 26 fish species were identified in ichthyoplankton collection, 86 species of teleosts were noted in trawl catches. The dominant components of ichthyoplankton were the walleye pollock eggs Gadus chalcogrammus, the larvae of the Pacific sand lance Ammodytes hexapterus and the larvae of sculpins gen. Gymnocanthus. Most species abundant in ichthyoplankton were among the most significant in trawl catches. The maximum abundance of ichthyoplankton, more than 600 ind./m2, in the area of the Northern Kuril occurred at the beginning of May. The structure of ichthyoplankton in April-May of 2015–2016 was quite similar, at the level of 60–70%.Practical significance. Knowledge of the main spawning areas of commercial fish and the places of development of their early stages is an important component for making decisions on the rational use of biological resources.