The Characteristics of Feeding Migrations of Hatchery-Reared Pacific Salmon Juveniles in the Sea of Okhotsk Basin and Adjacent Pacific Waters in the Autumn–Winter Period (Regional Identification, Abundance, Distribution of Catches, Biological Characteristics, and Mortality Rate Estimates)

Abstract

Long-term data (2011–2021) on feeding migrations of hatchery-reared Pacific (pink and chum) salmon in the Sea of Okhotsk and adjacent Pacific waters in the autumn–winter period are summarized. The study is based on materials (otolith samples and biological indices) collected during the TINRO trawl surveys and also on international statistics for releases and marking of Pacific salmon at Russian and Japanese salmon hatcheries. The major long-term patterns of intraspecific structure, migration routes, spatial distribution and sizes of catches, and the size–weight characteristics of fish from different regions have been determined for these species. Natural mortality rates of salmon juveniles at the stage of migration from the coastal zone to open sea waters have been estimated at a systemic level for the first time.