The Khazar or the Caspian Sea is a water area bound to Iran from the south and to Russia from the north. The sea, which is classified sometimes as the largest lake in the world, and sometimes as the smallest self-sufficient sea in the Earth, is the largest water area enclosed with the land. The closed nature of the Caspian Sea has made it home to unique animals and plants, thus it is a rich source of aquatics, which is why many people are fishing in the margin of the sea. Beach seine fishing is one of the oldest methods for catching bony fish, including whitefish, in the southern margin of the Caspian Sea, dating back several hundred years. According to some evidence, this type of fishing began in Bandar Anzali, and gradually spread to other parts of the southern margin of the Caspian Sea. Currently, about 10,000 people are fishing, under the form of 120 cooperatives, in the southern margin of the Caspian Sea. However, pollution is a serious and dangerous problem for this vast sea and its enclosed environment, so that annually about 122 thousand tons of pollutants from Caspian littoral states, including oil pollutions, household (domestic) and industrial sewage, different types of wastes and plastics, and pollutants of commercial fleets pollute the sea environment and endanger different biological species. Environmental degradation has affected not only life of biological species but also life of the local fishermen, with a 40% reduction in fishing rate last year, and as a result, the income of the fishermen, who this job is the only source of their income had a sharp decrease, making it hard for them to afford costs.
Continuation of this process will result in the extinction of marine species. It can also lead to unemployment of 10,000 Iranians, which itself has many security, social and political consequences.