Современное состояние макробентофауны Восточной Балтики в 1986 - 1988 гг.

In 1986 - 1988 three summer research cruises were made in ICES Subdivisions 26, 28, and 29 of the Baltic Sea. It has been established that considerable changes that have been taking place in the quantitative structure and composition of the bottom fauna communities since the 1960-ties may be attributed to the fluctuations in hydrological regime and increasing antropogenic load on the sea ecosystem. The disappearance of species, decrease in the number of communities and in the species diversity have been noted, as well as the increase in the average biomass of macrobenthic fauna. The upper boundary of the lifeless zone has risen. The abundances of species tolerant to pollution have been increased. In 1987 - 1988, the decreased water heat budget and salinity caused the increase in the abundance of relict crustaceans within the reduced area of their habitat. At present favorable conditions are observed for food items of fishes-benthophages.