According to the petition by the deputy director of security of the Mazandaran Governorate to investigate the causes of bird deaths, sampling of biological parameters (phytoplankton, zooplankton and macrobenthos), water physicochemical parameters (salinity, oxygen and nutrients), microbial contamination of water and sediments in the Ghaleh Payan Village of Behshahr City (Miankaleh), where it seems to have had the highest number of bird deaths, wasperformed by experts of the Caspian Sea Ecology Research Center.