Distribution and migration, growth, and biological parameters for Japanese sardine Sardinops melanostictus from Japan

The stock of Japanese sardine (Sardinops melanostictus) in the northwestern Pacific Ocean has increased substantially since the 2010s, accompanied by changes in its biological characteristics. This document summarizes recent knowledge on the distribution, growth, natural mortality, and maturation of Japanese sardine based on Japanese domestic stock assessments and recent scientific studies.

Recent year-classes have exhibited considerable growth reductions, which have been suggested to result from density-dependent effect and changes in feeding conditions. Mean length and body weight-at-age have shown declining trends, and maturation characteristics are also known to vary with stock abundance. These findings indicate that the biological characteristics of Japanese sardine are dynamic and respond to changes in stock size and environmental conditions. Such characteristics play important factors for future stock assessments and fisheries management.