The aim of this study is to investigate the communities and diversity of phytoplankton in some warm-water fish farming ponds in Mazandaran province. To conduct this study, three ponds were selected from the farm, and then 500 cc of the pond water was collected from three points of the pond using a rotner, and the sample was poured into a bottle and fixed in the same area with 4% formalin.The samples were transferred to the Planktonology Laboratory of the Caspian Sea Ecology Research Institute and the Inland Waters Aquaculture Research Institute for analysis, and then the samples were identified and their abundance determined in the laboratory. In this study, a total of 61 species from 5 phytoplankton phyla were observed that of which 15 species belonged to the Bacillariophyta phylum, 21 species to the Chlorophyta phylum, 14 species to the Cyanophyta phylum, 7 species to the Euglenophyta phylum, and 4 species to the Pyrophyta phylum. The highest density belonged to the Cyanophyta phylum with 67% of the total phytoplankton population, and the Chlorophyta phylum was in second place with 20% of the population.In this study, the phylum Bacillariophyta was ranked third with 12% of the total density. The group Euglenophyta had a very small share (1%) in these ponds, and the phylum Pyrophyta was very insignificant. In terms of density, the Cyanophyta phylum had the largest contribution to the phytoplankton composition of the ponds with 44%, and species such as Spirulina sp., Merismopedia sp., and Chroococcus sp. were dominant in it. After that, Bacillariophyta and Chlorophyta played an important role in the population structure of the ponds.Euglenophyta were also present with species such as Trachelomonas sp. and Euglena sp., indicating relatively organic-rich conditions in the water. These results indicate the importance of Cyanophyta as the dominant group and the complementary role of other phyla in the ecological stability of thermal pools.
tahami F, Mirbakhsh M, Ahmad Nejad Chehreh A, Ghaffari H. Study of phytoplankton communities in warm-water fish farming ponds in Mazandaran province. JAIR 2026; 14 (1) :11-20 URL: http://jair.gonbad.ac.ir/article-1-932-en.html