Аннотация:On the basis of own long-term observations of zooplankton species diversity in the Curonian and Vistula lagoons of the Baltic Sea and literature sources of the late 19th – early 20th centuries, the analysis of variability in zooplankton species composition has been carried out. The conclusion is made, that in general the species diversity in the Curonian and Vistula lagoons has not been changed. The replacement of o-mesosaprobic species by ?-mesosaprobic ones due to the higher trophic status of the basins is noted.
