Biological structure and abundance dynamics of Pacific rainbow smelt Osmerus dentex (Osmeridae) of the Amur river

Abstract

Data on spawning migrations, biology and abundance of the spawning group of the pacific rainbow smelt Osmerus dentex of the Amur River in the period from 2014 to 2021 are presented. According to the data of mass labeling of producers, the smelt extracted in the Amur estuary and the Amur riverbed belongs to one unit of stock, the migration routes of producers and the spawning rate have been clarified, and a decrease in the number of spawning herds has been recorded. Analysis of the main biological indicators revealed a significantly significant (p<0.001) decrease in size and mass characteristics, a change in age structure, and a tendency to increase the proportion of females in the spawning herd. The analysis of fertility dynamics revealed a decrease in the indicators of individual and relative fertility of fish of the spawning herd in 2017 (p<0,001), however, in general, the observed changes fit into the range of average long-term fluctuations.