The results of the bottom trawl survey off the southern Kuril Islands and southeastern Sakhalin in the fall of 2025

Abstract

The aim: assessment of stocks and prospects of fishing for aquatic biological resources off the southern Kuril Islands and southeastern Sakhalin.

Methods: data collection was carried out in accordance with generally accepted methods in ichthyological practice. The bottom trawl DT/TV 27.1/24.4 was used as a fishing gear.

Innovations: up-to-date data on the composition, ratio, abundance, and biomass of nekton in the southern Kuril Islands and southeastern Sakhalin in the autumn of 2026 have been obtained.

Results: a bottom trawl survey was conducted to assess the stocks of aquatic organisms off the southern Kuril Islands and southeastern Sakhalin, which totaled 24,3 billion specimens and 899,9 thousand tons, of which cod accounted for about 70% of the abundance and 65% of the biomass. 106 species of fish from 27 families were recorded in bottom trawl catches in the southern Kuril Islands, while 108 species of fish from 23 families were recorded in southeastern Sakhalin. An analysis of the spatial distribution of cod showed that during the research period, its densest clusters were located on the traverse of the bay Kasatka, south of Cape Aniva and in the southwestern part of the bay Aniva. While the juveniles of the saffron were mainly located in the South Kuril Strait, and large individuals — in the bay Terpenia. In the Southern Kuril family, one of the dominants was the southern rock sole, the main aggregations of which were located in the South Kuril Strait and at the southern tip of the island Iturup. In turn, Sakhalin’s flounder catches were dominated by yellowfin flounder, its dense accumulations were noted in the northern part of the bay Terpenia.

The practical significance: the results of the study will serve as the basis for developing materials for forecasting the total number of species of aquatic biological resources in the southern Kuril Islands and southeastern Sakhalin.