Prospects for the pink salmon fishery in the Russian waters of the Bering and Okhotsk Seas in 2024 based on the analysis of the juveniles trawl surveys aboard RV TINRO and RV Professor Kaganovsky in the fall of 2023

Abstract

Trawl surveys on juvenile pink salmon in fall season provide crucial information for forecasting their returns because of lower mortality of the juveniles in this season compared to their mortality during downstream migration in rivers or in the early marine period. Surveys by two research vessels give an opportunity to cover vast are- as in a short time and to exclude repeated counts of actively migrating fish on adjacent transects. The surveys in the Bering and Okhotsk Seas in the fall of 2023 were well planned and done, so the main aggregations of pink salmon in the offshore areas were assessed, ensuring good reliability of the data on this species abundance used for forecasting pink salmon adults returns and catch. Two regional groupings of juvenile pink salmon in the Okhotsk Sea were differentiated in mixed catches using the EM clustering method; the ratio of the «northern» and «southern» groupings was 40:60%. The total counted abundance of juvenile pink salmon was 0.33.109 ind. in the Bering Sea and 1.40.109 ind. in the Okhotsk Sea that allowed to expect preliminary the returns of approximately 100.106 ind. to the Bering Sea rivers and 208.106 ind. to the Okhotsk Sea rivers in 2024.

Keywords

• fishery forecasting
• clustering
• catch of fish
• salmon returns
• salmon fishery
• pink salmon
• trawl survey
• differentiation
• juvenile
• fish abundance
• water temperature