The proto-Baltic Sea emerged from the melting of the Scandinavian Ice Sheet and was populated by fish of the Arctic and Arctic-boreal complexes, migrating from adjacent rivers southwards. The resulting body of water underwent several evolutionary stages over 16 000 years under the influence of climatic and geological-morphological factors, periodically forming and losing its connection with the ocean. Environmental conditions, primarily salinity, determined the composition of the Baltic Sea’s ichthyofauna. The evolution of the fish populations can be indirectly traced through archaeological finds of fish remains. Before the Common Era, the ichthyofauna developed under the influence of natural climatic and geological-morphological factors; human influence through artisanal fishing was insignificant. With the onset of the Common Era, due to an increasing population, human impact on the ichthyofauna through fishing became significant. In the 19th century, the list of ichthyofauna of the Baltic Sea included 73 fish species. The technological revolution of 21st century led to the emergence of industrial fisheries, alongside artisanal ones, which became dominant in the 20th century. The introduction of invasive species into the sea and a more thorough study of the ichthyofauna’s composition increased the number of species to 82 in the 21st century. Selective fishing of commercial fish species, anthropogenic impacts, and climate factors have become limiting factors for the modern ichthyofauna of the Baltic Sea basin, affecting the abundance of the main commercial species and the development trends of the ichthyofauna.
Гущин et al. (Wed,) studied this question.