Anzali Lagoon (Gilaki: اٚنزٚلي سٚل ) (also Anzali Mordab, Anzali Bay, Pahlavi Mordab, Pahlavi Bay or Anzali Liman) is a coastal liman, or lagoon, in the Caspian Sea near Bandar-e Anzali, in the northern Iranian province of Gilan. The lagoon divides Bandar-e Anzali into two parts, and is home to both the Selke Wildlife Refuge and the Siahkesheem Marsh.

History

Although the lagoon suffers from pollution, it is known as a good place for bird watching. The lagoon's water ranges from fresh near the tributary streams to brackish near the mouth into the harbor and the sea. Studies indicate that in the 19th and early 20th centuries that the lagoon had a much higher salinity. The lagoon has decreased in size since the 1930s to less than a quarter of its former extent. However, in the last ten years water salinity has increased both by the rise of the level of the Caspian Sea which has caused greater interchange of waters, and due to greater salt transport in incoming "fresh" water due to increased upstream irrigation. The lagoon has been listed in Ramsar Convention since 21 December 1975.

Fishery

Prior to 1950 the Anzali Lagoon provided about 70% of the commercial fish taken in Gilan Province, with catches of over 5,000 tons annually. Commercial fishing was done during the spring and autumn spawning cycles when the kutum, pike-perch and bream, would enter the lagoon from the Caspian. However, a number of factors acted against the continuation of the fishery and by the time commercial fishing ceased in 1960 annual catches were less than 100 tons. Heavy siltation from increased upstream irrigation had resulted in the shrinkage and shallowing of the lagoon, increased pollution of the source waters and eutrophication due to an increased nutrient load contributed to the destruction of the fishery. More recently the surface of the lagoon has become gradually overgrown with aquatic macrophytes, primarily the non-native water-fern, Azolla filiculoides, and this has caused increased eutrophication, creating large areas of the lagoon where there is insufficient dissolved oxygen for fish to survive.

Geography

Located in an area of 15,000 hectares near the northern port city of Bandar Anzali in Gilan Province. Its geographical coordinates are located at 28 to 37 north latitude and 25 to 49 east longitude. Due to its geographical location, Anzali wetland is distinguished among other wetlands in Iran in terms of excessive humidity and rainfall. Although this subject fluctuates depending on the amount of rainfall and the duration of the drought. Anzali is one of the few Iranian wetlands which have been registered as an international wetland in the 1975 Ramsar Convention. Wetlands are considered the most biologically diverse of all ecosystems; however, the Anzali Wetland has also been the victim of the authorities neglect, putting it in danger of grave ecological changes. The use of Anzali Wetland's bank as the city dump and the release of human and industrial waste into the wetland have already put in danger the lives of animal species and at least 78 species of birds living in the area. Besides, some local authorities plan to build a sports field in a peninsula connected to the wetland. This will be the final blow to the wetland, which has so far been prevented only by the serious opposition of environmentalists to the construction of the sports field.

Islands

Among the islands located in the lagoon are Bozorg, Kouchak, and Mianposhteh.

Climatic conditions

Anzali lagoon generally has hot and humid summers and mild winters. The atmospheric characteristics of Anzali lagoon are similar to Anzali and Ghazian, but the amount of humidity in the lagoon is higher than the neighboring areas. The minimum temperature in winter is close to or equal to zero degrees Celsius and rarely falls below zero. The maximum temperature in the middle of summer is between 33 and 36 degrees Celsius.

Ecology

This wetland has a special environment due to the presence of animals and plants, the morphology, shape of the stream bed, the connection with the rivers and the sea.

Biodiversity

Anzali Wetland is a spawning place for aquatic animals and a habitat for native and migratory birds. This wetland has a unique ecosystem with hundreds of plant species, 50 fish species, and more than 100 bird species. Anzali lagoon is also one of the most important sources of reproduction and production of sturgeon and bony fish in the Caspian Sea.

Plants

The plants of this wetland are divided into three categories: submerged plants, floating plants and marginal plants.

marginal plants

In this type of plants, all or most of the vegetative and reproductive organs of the plant are located outside the water. Most of the plants forming this layer grow on the edge of the marsh and nearby rivers. The following plants can be seen in this layer: Phragmites australis ,Sparganium ,Typha latifolia, Sirpus Polygonum ,Blue oregano Blue slingshot ,Blue heron Bottoms ,Nelombo ,horse tail

catchment area

The lagoon has an area of about 374 thousand hectares. Anzali Wetland has 11 main rivers and 30 sub-rivers which, after irrigating the fields and paddy fields upstream, enter it along with the surface flows of the watershed of the Wetland. The maximum water depth of the lagoon in spring and in the western areas of the lagoon reaches 2.5 meters, which varies due to the fluctuations of the water level of the Caspian Sea. The catchment area of Anzali lagoon is as follows: • 9.53%: forest and pasture • 2.33%: Agricultural lands • 7.8%: wetlands, dams and pools • 7.3%: areas used privately by people.

Tributaries

The following rivers and streams flow into the Anzali Lagoon.