Study of zooplankton in the waters of the southern Caspian Sea region (Mazandaran-Goharbaran)

Zooplankton sampling was sampling was performed by a sampling net with a spring size of 100 microns. Since 2001, there have been changes in the population composition of zooplankton species, while in 1994 and earlier Eurytemora spp. Zooplankton predominated at depths of more than 20m. Currently, in the years after 2001, more than 95% of the zooplankton population in the southern Caspian basin is Acartia tonsa. Although in this study the dynamics of the zooplankton population was different, in all seasons Copepoda was the predominant group of zooplankton. A total of 24 species of zooplankton from the groups of Copepoda, Rotifera, Protozoa, Cladocera and two species of Meroplankton from Cypris balanus and Lamellibranchiate larvae from bivalve larvae have been observed. Among the factors of entry of non-native animals, including the comb M. Leidyi, nutrient entry through the Nekarood river, different amounts of solar energy intake and consequently temperature and water currents can cause differences in zooplankton population in Goharbaran region.