Fishing under climate change: Dynamics of composition and structure of catches in the Russian Black Sea in the XXI century

Abstract

Currently, the Black Sea ecosystem is undergoing significant changes, and that affects the dynamics of the species composition of catches. The main reasons for the change in the Black Sea ichthyofauna are considered to be: fishing, anthropogenic water pollution, invasion of new species, and the effect of large-scale climatic and related oceanological and hydrological processes on the productivity characteristics of commercial Black Sea fish. With no understanding the patterns of the effect of these factors on ichthyofauna, it is impossible to rationally use bioresources and protect nature. The aim of the work was to study the effect of climate warming on the species composition and structure of catches in the Russian Black Sea in the XXI century. The authors had used: the results of own ichthyological observations; data published on the composition of the Black Sea catches; and the information available on the official websites of the Ministry of Agriculture of the Russian Federation, the Federal Agency for Fishery, and its Sea of Azov – Black Sea Territorial Administration. The analysis of the possible effect of global warming on the results of fishing in the Russian Black Sea was carried out. It is shown that in the XXI century, the ratio of thermophilic fish, which spawn in the summer, increased; those species are European anchovy Engraulis encrasicolus (Linnaeus, 1758), red mullet Mullus barbatus Linnaeus, 1758, and horse mackerel Trachurus mediterraneus (Steindachner, 1868). As established, the dynamics of the ichthyofauna in the area is determined by at least four processes related to water warming: improvement of reproduction conditions and increased survival of eggs and juveniles of thermophilic species; change in the intraspecific structure; invasion and naturalization of Mediterranean species with the subsequent change in the food relationships within the ecosystem; and concentration of psychrophilic species at greater depths. The need for a thorough study of this issue is concluded, aimed at long-term forecasting of the raw material base state of the fishing industry in the Russian Black Sea.