The Caspian Sea (Darya-ye Khazar, Darya-ye Mazandaran) basin is here taken to include both the rivers draining to that sea and the sea itself within Iranian territorial waters. This basin, in its land part, is elongate, extending from the Turkish border almost to the Afghan border and only acquires some width where the Safid River and its tributaries penetrate the Alborz Mountains in the west. According to Pirnia (1951) the Caspian basin in Iran (excluding the sea) encompasses 182,100 sq km while according to Zakeri (1997) this figure is 256,000 sq km, 15.5% of the whole country. Zakeri (1997) records 864 small and large rivers, including the Safid River with a catchment of 67,000 sq km. Much of the information on the Caspian Sea itself is restricted to waters of the former U.S.S.R. and there is relatively little on Iranian territorial waters. Rozengurt and Hedgpeth (1989), Kosarev and Yablonskaya (1994), Mandych (1995) and Golubev (1996) summarise much of the recent Soviet literature and a general review is given by Mamaev (2002).

An ongoing and developing source of information on this sea, the surrounding land, its history, its management, biodiversity strategy and action plan, and a wide sweep of environmental problems is the Caspian Environment Programme (CEP), Baku, Azerbaijan at www.caspianenvironment.org. This site has numerous documents and reports on-line, some with authors, e.g. Katunin (2000), Ivanov and Katunin (2001), ERM-Lahmeyer International GmbH, DHI Water & Environment and GOPA Consultants (2001a), others appearing under CEP or TACIS (Technical Assistance to the Commonwealth of Independent States, European Union), e.g. TACIS and UNDP (2000), TACIS (2002), CEP (1998, 2000b, 2002). These reports include information on the fishes and fisheries but are best referred to for the interactions between people and the environment. Kiabi et al. (1999) describe the wetlands and rivers of Golestan Province at the southeast corner of the Caspian Sea. Razavi (1999) gives an introduction to the ecology of the sea in Farsi. Nezami et al. (2000) and CEP (2001) give recent general descriptions of the Iranian Caspian coastal zone, the important rivers, wetlands, water quality, climate, pollutants, and fisheries. www.bibliothecapersica.com/articlenavigation/index.html, under Caspian Sea, downloaded 24 December 2004 also gives an overview of this basin. Nadim et al. (2006) review the management of coastal areas in the Caspian Sea.

The Caspian Sea is the largest "lake" or inland water body in the world at 436,284 sq km, a surface area encompassing 18% of the total area of all lakes in the world, about the same area as Great Britain (other surface area figures are 378,400 sq km, 384,400 sq km and 390,000 sq km - data of this nature varies quite markedly between apparently authoritative sources). The volume is 78,100 cu km, 44% of the total volume of inland lakes of the world. Its north-south extent is 1204 km and width is 204 to 566 km. The shoreline, including islands, extends for 7000 km, 1000 km of which is Iranian. The catchment area is 3.6 million sq km. Dumont (1998) presents arguments for this water body being a true lake and not a sea.

North, Middle and South Caspian basins are recognised, divided by shoals. Iranian waters fall within the South Caspian Basin which occupies 148,700 sq km and is separated from the Middle Caspian by the Apsheron Bank. The South Caspian holds over 65% of the sea's water and is the deepest basin, to -1000 m in depressions, average - 325 m. The northern basin holds only 1% of the water.

The sea receives 291 cu km from river run-off and 87 cu km from precipitation but loses 374 cu km from evaporation and 11 cu km to overflow into the Kara Bogaz Gol (Gerasimov, 1978b). The Volga River accounts for 76.3% (82% according to Dumont (1995)) of the inflow of rivers, the Kura River 4.9%, the Ural River 3.7%, the Terek River 3.2% and the remaining rivers including all those of the Iranian shore 11.9%. Iranian rivers account for only 5% of the Caspian inflow, Iran has 7% of the catchment area, 14% of the coast, contributes 3% of the settling solids, and 2% of the fishery (Badakhshan and Shayegan in Glantz and Zonn, 1997). The Volga has its headwaters near Moscow and is 3688 km long with a catchment area of 1,360,000 sq km and a mean annual flow at Volgograd of 8380 cu m/sec. The Volga is of prime importance in the Caspian Sea basin to migratory fishes as a spawning site and the biology of these species has been studied extensively. Often these studies provide the basis for much of the knowledge of Iranian fishes to the south.

Zenkevi(t)ch (1957; 1963) and Barimani (1977) have reviewed the geography, hydrology and biology of the Caspian Sea, Moiseev (1971) summarises the living resources of the whole sea, Karpinsky (1992) aspects of the benthic ecosystem, and Knipovich (1921), Il'in (1927a), and Nevraev (1929) give accounts of Iranian coastal waters and regional fisheries in the early twentieth century. Zahmatkesh (1993) describes the gammarids and bottom sediments, Fallahi (1993) the plankton and Soleimani (1994) the benthic fauna in Iranian waters. Mamaev (2002) is a recent general overview.

Water balance for this sea depends on a delicate balance of inflow, evaporation, precipitation, climate, and abstraction for human needs. Water 10 m deep or shallower has a bottom of sand and gravel while at greater depths of 50-100 m clay and softer sediments increase. There is more sand in these greater depths off Gilan compared with off Mazandaran.

Maximum depth is 1025 m, mean depth is 184 m, and depth below sea level is -28 m (-27.66 m averaged over the past 2,500 years according to Dumont (1998)). There are natural water level fluctuations - the figure cited is from 1983; in 1978 it was -29.02 m, the lowest recorded since observations began (Voropaev and Velikanov, 1985). Petr (1987) has pointed out that a decline below -28.5 m would result in a change in salinity distribution and in water currents mixing riverine and sea water. A decline in productivity would follow. A fall of only 1 m would cause a 60% reduction in fish food supply and, since this fall poses barriers to migration to better feeding grounds, a further 20% loss in food supply. Recently however, since 1978, the sea has begun to rise, by 2.1 m from 1978 to 1993 to -26.95 m, with a possible rise of 3 m in the next 25 years. Vaziri and Borghei (1995) give an average rise of 1.2 cm a month for the period 1986-1993. The sea rose 26 cm in 1994. However, over the past 2500 years the sea level has not exceeded -25 m and is not anticipated to do so in the near future; the level is cyclical (Rychagov, 1997; Gorji-Bandpy and Hooman, 2004). The reason for the rise is probably a climatic shift (Mandych, 1995; Shayegan and Badakshan, 1996; Kobori and Glantz, 1998) but a sheen of oil from pollution may be helping in the reduced evaporation of 7-10% observed over two decades. Tectonic shifts of the sea floor may also be a contributing factor. Predictions of water level changes have proved unreliable so schemes to ameliorate rises or falls are unwarranted and could be catastrophic (Abuzyarov, 1999). Georgievskiy (2001) however, predicts a lowering of the sea level to -27.6-28.9 m by the year 2030 from -27.0 m in 2000. Klige and Myagkov (1992) examined the water balance of the Caspian Sea and predicted a rise in sea level to 1995-1997 and then future declines of the order of several metres in the next century.

The rise in water level is engulfing buildings including industrial sites which will pollute the waters of the Caspian further. Iranian towns and cities damaged include Babolsar, Tonekabon, Ramsar, Ashuradeh, Bandar-e Torkoman, Anzali, Astara and Kolachai (Zonn in Glantz and Zonn (1997)). Fish caught near Nowshahr in 1999 were contaminated with oil pollutants (Tehran Times, 1 November 1999). The complex of chemical, petrochemical and metallurgical plants at Sumgait near Baku in Azerbaijan produces 335,000 tonnes of mostly toxic waste including dioxins. Hundreds of waste lakes of oil near Baku are being slowly engulfed by the rising Caspian. Nasrolazadeh Saravi (2001) and Khatoonabadai and Dehcheshmeh (2006) describe oil pollution in Iranian coastal waters although it is much less than near Baku, particularly in Mazandaran and Golestan. Heavy metals enter down the major rivers from mining and industry and the effects from the Kura River may have rendered the coast of Azerbaijan almost untenable for life (Bickham, 1996; Pohlman and Naismith, 1996; Rowe, 1996). Radioactive waste, both liquid and solid, is found in low lying depressions around nuclear power plants and is liable to enter the Caspian (Rodionov, 1994; Dumont, 1995).

On the plus side, sturgeons may benefit from easier access to spawning grounds (Ottawa Citizen, 9 July 1994; 3 July 1995) but this is probably offset by the pollution load of the major spawning rivers.

In contrast to the recent rise in sea level, a series of reports have appeared in past scientific and popular literature on the falling level of the Caspian Sea and diversionary schemes to combat this (e.g. Kovda, 1961; Lamb, 1977; Hollis, 1978; Gribbin, 1979; Micklin, 1979; 1986; Golden, 1982; Rich, 1982; 1983; Voropaev and Kosarev, 1982; Voropaev and Velikanov, 1985; Pearce, 1984; Ryan, 1986; Perera, 1989; Rozengurt and Hedgpeth, 1989; among others). The Caspian dropped 2.3 m between 1930 and 1962 and area has decreased by 10% or 40,000 sq km. Recent historical levels appear to be between -25 and -26 m, average -25.8 m. Changes in level of the Caspian due to natural or other causes in historical and pre-historical times have been reviewed above. Fall in the sea level increases salinity, destroys habitat and blocks spawning migrations, although some effects are less in the southern, Iranian Caspian because of the larger water mass. The Volga accounts for 76% (some reports say more than 80%) of the river input to the Caspian Sea. The Volga is now extensively dammed, as are other rivers in this basin, and its waters used for industry and agriculture. There are 8 large dams on the Volga, the largest being the Kuibyshevskaya with a reservoir area of 6450 sq km and a total volume of 58 cu km. Dams in the Caspian basin provide almost one third of the hydropower of the former U.S.S.R. (Rozengurt and Hedgpeth, 1989). Flow into the Caspian has been cut by at least 25% and in spring, the time of spawning migrations, by as much as 37% for the Volga-Kama systems. Berka (1990) reviewed the effects of water level changes on the northern Caspian fisheries. The North Caspian was designated as an "ecological disaster area" in 1992 because of water pollution input from the Volga. The delta is eutrophic with cyanobacterial blooms being common, affecting fish survival (Saiko in Glantz and Zonn, 1997).

The decline in sea level has been reversed in recent years and a rise of nearly 2 m was reported and, in Turkmenistan, a shoreline advance of 2-3 km in places (Rich, 1991; Anonymous, 1992a; Golub, 1992; Ottawa Citizen, 9 July 1994; Priroda, 5:3-25, 1994). This will have positive effects for some fisheries and wetland conservation but negative effects on recent, low-lying construction including oil refineries and wells in Azerbaijan and a nuclear waste dump in Turkmenistan which would cause massive pollution from oil and radioactive compounds (Pearce, 1995). Environmental hazards to the fisheries caused by sea level rise include eutrophication from farmland covered by the sea, pesticides and herbicides from inundated farmland, salt water penetration into wetlands, input of solid municipal and industrial wastes and vegetation, destruction of fish habitat, and input of soil altering the ecosystem (Shayegan and Badakhshan in Glantz and Zonn, 1997).

It has been suggested that the rise in sea level is due, in part, to seepage from the Aral Sea basin and that this could be halted by setting off underground explosions. This smacks of the large-scale alteration to the environment favoured by Soviet planners to combat the fall in sea level - both are grandiose and have unknown consequences for the environment. Climate change is probably a major factor abetted by the closing off of the Kara Bogaz Gol (responsible for an estimated 40-45 cm rise alone) and diversion of Siberian rivers into the Ural River in the northeastern Caspian (Khan et al., 1992).

Much of the former southern U.S.S.R. is water poor and a solution to this and the falling Caspian level has been advocated. This would involve diversion of north flowing Siberian rivers at a cost $40 billion. The potential for environmental damage on a local and even global scale caused this scheme to be shelved in 1986. The project involved excavations using nuclear explosives, drowning of forests and construction of canals thousands of kilometres long. Reduced flow into the Arctic Ocean could affect ice cover which influences atmospheric pressure and circulation patterns over the whole northern hemisphere. This Soviet plan has recently been revived (Pearce, 2004).

There is an abundance of historical and other evidence for variations in Caspian Sea level and its connections with other water bodies in both recent times and over several million years (Huntington, 1907; Ehlers, 1971; Lamb, 1977; Gerasimov, 1978b; Hsü, 1978; Coad, 1980c; Rögl and Steininger, 1984; Wossugh-Zamani (1991c); Oosterbroek and Arntzen, 1992; Sal'nikov, 1995; Mamedov, 1997; Rychagov, 1997; Caspian Environmental Programme, 2000; Grigorovich et al., 2003; Kotlík et al., 2008). Brooks (1949) maintains that the Oxus (= Amu Darya) flowed into the Caspian in the 14th century instead of the Aral Sea. Shnitnikov (1969) and Gerasimov (1978a) report flow along the Uzboi channel north of the Iranian border into the Caspian from the Aral Sea basin at several periods from the third millennium B.C. to the 16th century. Sal'nikov (1998) illustrates connections between the Amu Darya and the Caspian Sea from the Pleistocene to the 20th century. The connection between the Caspian and Amu Darya and Aral Sea was interrupted about 20,000 years ago when the Amu Darya turned north, was reconnected about 10,000 years ago, and essentially interrupted about 4000 years ago. These regular contacts have resulted in an Aral Sea ichthyofauna with "weakly pronounced endemics", although the Amu Darya ichthyofauna has a number of clearly defined endemics which are not yet found in the Caspian Sea basin (but see below under Tedzhen River basin). Dunin-Barkovsky (1977) records level fluctuations of up to 50 m during the Holocene due to variations in the general moistening of Eurasia and intermittent warming and cooling variously associated with changes in precipitation and evaporation. Ice melt from the Fennoscandian ice cap, as late as 4000 B.C., added large volumes of water to the Caspian and an overflow to the Black Sea was then possible. Berg (1948-1949) maintains that Atherina presbyter and Syngnathus abaster entered the Caspian at about this time. Some fishes, such as Salmo trutta, are probably immigrants from Arctic regions and certain cyprinoids and percids are freshwater immigrants. Bianco (1990; 1995b) points out that, at every glacial- interglacial ice melting phase, a network of connected rivers and lakes allowed primary freshwater fishes to disperse in the northern Palaearctic. Other fishes are relicts of earlier transgressions. Such species as herrings (Clupeidae), gobies (Gobiidae) and possibly sturgeons are believed to have evolved from the marine fauna of the Tethys Sea which ran from the modern Atlantic to the Indian Ocean before the Sarmatian basin formed. The uplift of eastern Anatolia and the Alborz in the Early Miocene between 20 and 17 million years ago (MYBP) closed a seaway from the Indo-Pacific which had extended into the Eastern Paratethys (= Black-Caspian-Aral sea in modern terms). The connection reopened in the Middle Miocene 16.8-16 MYBP) but by the Late Miocene a Sarmatian basin was cut off from the open seas and developed a unique marine fauna (Ekman, 1953). This was mostly lost as salinity decreased from freshwater input and a new fauna developed. A series of connections and breaks with the Black Sea, Mediterranean Sea and the Atlantic Ocean in various combinations with brackish and freshwater episodes gave varying opportunities for faunal interchanges and evolution. The Caspian fauna differs from the Mediterranean one because its only communication was via the Black Sea which acted as a "filter". When the Black and Caspian seas were well connected, the link to the Mediterranean was broken, and when the Black and Mediterranean seas were connected, the Caspian connection was not well developed. Mamedov (1997) and Rychagov (1997) review late Pleistocene and Holocene changes in Caspian Sea level, Chepalyga (1984) and Gerasimov (1978b) review water level changes and connections with the Black Sea over the last 80,000 years, Kosarev and Yablonskaya (1994) and Mandych (1995) for the last 500,000 years and Grigorovich et al. (2003) for the last 12.5 million years. Bianco (1990) gives an overview of the palaeohistory of the Paratethys Basin. Fluctuations in water level are correlated with climate changes Kotlík et al. (2008) using multiple gene phylogeography found the Black and Caspian seas supported separate populations of Rutilus frisii during the last glaciation, although this separation was not complete and gene exchange occurred, with the majority of migrations in the Pleistocene.

The total Caspian Sea drainage area is said to be 3,700,000 sq km, about 25% of the continental land mass of the U.S.A. (Rozengurt and Hedgpeth, 1989). The basin includes about one fifth of the crops and one third of total industrial output of the former U.S.S.R. (Rozengurt and Hedgpeth, 1989). Its northernmost waters are north of St. Petersburg (= Leningrad) in Russia while its southernmost waters rise on the flanks of the Zagros Mountains in Iran. This ranges from the subarctic to the subtropical region and is very diverse in climate and geology. Natural runoff in the South Caspian Basin ranges from 8 to 18 cu km while in the North Caspian it is 207-375 cu km. However the North Caspian is very shallow (mean 4-5 m, maximum 20-25 m) compared to the south Caspian (mean 325-334 m, maximum 980-1025 m). This is also reflected in the volume, 400-700 cu km compared to 49,000-77,500 cu km. Salinity is about 12-13‰, increasing in isolated bays and decreasing near river mouths. Summer temperatures in the south reach 27°C and in winter 9°C but the northern parts ice over. The Gorgan River area reached 30.9°C (Laloei, 2006). Surface water temperatures for the South Caspian are reported as 7.0-10.3°C in winter, 7.9-14.0°C in spring, 25.0-29.0°C in summer and 12.0-19.0°C in autumn (Rozengurt and Hedgpeth, 1989). These authors also report salinity ranges of 12.5-13.0, 12.3-13.2, 12.6-13.6 and 12.3-13.5‰ for the same seasons, oxygen levels of 7.0-7.8, 7.0-8.2, 5.0-6.0 and 6.0-8.0 ml/l, and pH values of 8.48, 8.44, 8.44 and 8.50. Vertical mixing occurs down to 50-150 m in the South Caspian (Mellat-Parast, 1992). There is little oxygen below 200-300 m and no fish life although changes to the hydrological regime of the Volga have increased aeration and oxygen content of deeper layers in the south Caspian, down to 600-800 m. The Caspian has no tides but sustained winds can cause seiches, local and temporary rises in sea level. There is a current along the Iranian shore from west to east. The shelf along the Iranian coast is narrow (6-10 km) and steep (Kosarev and Yablonskaya, 1994). Beaches are usually sand with shell gravel on the bottom further out. The extreme western coast has some shingle beaches and west of Alamdeh in the central part is some rocky shore but there are no major cliffs or headlands. The shore has coastal dunes, spits and bars with lagoons inland, either brackish or fresh, grading into the higher and dryer foothills.

Much of the coast was once forested, but it has been actively cleared and marshes reclaimed as rice paddy. Rice paddies are now being investigated for fish cultivation. About 300-500 kg of carp "seed" and a 10% increase in paddy production per hectare was recorded during the rice cultivation season. Extending this into the fall gave a production of 750-1000 kg of fish and duck and in winter 5.5-8.0 t of rainbow trout (Tehran Times, 1 October 2000). Gilan is attempting a production of 2 kg of trout per sq m of paddy field, with the aim of harvesting 46,000 t of fish (IRNA, 14 November 2001). Mazandaran has the highest farm fish production in Iran at 28,000 tonnes (2006-2007) and is expected to reach 50,000 t by 2010 (www.mehrnews.ir, downloaded 8 February 2007). The area of forests in northern Iran has been reduced from 3.4 million hectares in 1962 to 1.8 million hectares in 1977 and about 1 million hectares or less in 1995. In Gilan, 975,000 cu m of wood from the forests are burnt annually by cattle breeders for heating or cooking purposes or for production of dairy products. Additionally 450,000 cu m of wood are used for industrial purposes. Reforestation cannot keep up with the losses and forests have been reduced by half over the past 50 years (Barzegar, The Agricultural and Cattle Breeding Publication, No. 761, 22 December 1997, from www.netiran.com/Htdocs/Clippings/Deconomy/971222XXDE01.html). As a result floods now occur with destruction of fish habitat after 30-40 hours of rain where previously no flooding occurred after even 4 days of rain (Hamshahri, Tehran, 628, 20 February 1995). Abstraction of water for irrigation (60% of water use) has severely reduced water levels and runoff rates necessary for reproduction of fishes. Estuarine habitats have been degraded inhibiting the survival of eggs, larvae and juveniles of anadromous and semi-anadromous fishes (the latter are species which spawn in the lower stretches and deltas of rivers where salinity is optimal at 8 g/l for many commercial species, e.g. Sander lucioperca, Cyprinus carpio, Rutilus rutilus). Over 90% of coastal streams along the Caspian shore are dry in July in Iran because of irrigation demands. As a result larvae of spring spawners are flushed into fields where they die, migration and late summer spawning of Aspius aspius and Barbus brachycephalus are obstructed, and Salmo trutta caspius and Rutilus frisii kutum populations are depleted because they cannot spawn in the shallow, warm, weed-choked water. Nursery and reproductive areas for Abramis brama, A. sapa, Blicca bjoerkna, Aspius aspius, and Sander lucioperca among others are confined because of their low tolerance to salinities above 7-8‰. Without an adequate runoff, the sea encroaches on the estuary. Nasri-Chaari (1994) cites physical obstacles, sand removal from river banks, overfishing and water pollution for declines in fish migration in recent years.

An earlier, general work including fishes of the Iranian Caspian Sea and coast is Berg (1948-1049). A more recent work is the atlas of the fish species in the Iranian Caspian Sea in English and Farsi by Jolodar and Abdoli (2004).

The commercially important species of fish were summarised in Abzeeyan, Tehran, 5(7):VII-IX (1995) and are divided into sturgeons (Acipenseridae, 4 species) and bony fishes (3 species of kilkas in the genus Clupeonella of the family Clupeidae; herrings or Alosa spp. also in Clupeidae; 5 species of the family Cyprinidae namely Rutilus frisii, Cyprinus carpio, Abramis brama, Rutilus rutilus and Aspius aspius; 2 species of mullets, family Mugilidae, Liza auratus and L. saliens; a member of the perch family, Percidae, namely Sander lucioperca; and a member of the salmon family, Salmonidae, namely Salmo trutta caspius). About 70% of Rutilus frisii is caught in Gilan Province, while 60% of mullets and 75% of sturgeons are caught in Mazandaran Province. More than 50% of the sturgeon catch is Acipenser stellatus and 10% is Huso huso, the remainder being A. gueldenstaedtii and A. persicus, with a yearly catch for all sturgeons of about 2500 tonnes. Sturgeon fishing is carried out by the government and no private sector fishing is allowed because of the value of this fishery and the need for careful management. Accidentally caught sturgeon must be released or turned over to the government operation. Ivanov (2000) summarises the biological resources of the Caspian Sea from a Russian perspective with some comparative figures from Iran. Generally, catches in Iranian waters are always less than those in former Soviet Union countries combined. A particular exception is Rutilus frisii (safid mahi), an esteemed fish in Iran.

About 25% of the Iranian total fish catch is from the Caspian coastal area (CEP) and figures for the Iranian Caspian Sea in tonnes are:-

Year	All fish species	Kilka	Sturgeon flesh	Caviar
1976/77	8,428	1131	2368	221
1981/82	10,466	1341	1914	234
1986/87	11,084	2384	2500	303
1991/92	34,596	13,817	2208	283
1992/93	40,598	21,527	2198	262
1993/94	52,768	28,730	1170	217
1994/95	69,700	51,000	1700	218
1995/96	58,300	41,000	1500	182
1996/97	74,100	57,000	1600	195
1997/98	76,200	60,400	1300	151
1998/99	101,500	85,000	1200	157

The fish harvest from the southern Caspian coast of Iran for the 7 month period October 1999-April 2000 dropped by 11% over the same period from the year before, from 8630 t to 7710 t (IRNA, 10 May 2000). The decline was attributed to a rise in fish prices which encouraged illegal fishing and to habitat loss. The value for the whole Caspian fisheries is given as $6 billion by Nezami et al. (2000). A proposal for a Caspian Fisheries Commission is given by TACIS (1999; 2000b) and ERM-Lahmeyer International GmbH et al. (2001b). It would aim to conserve and utilise the living aquatic resources, including the management of fish stocks such as kilka, herrings and mullets, as well as the famous sturgeons. These species all have transboundary stocks requiring cooperative management between countries. Articles aim to protect traditional fishing for sturgeon along the Iranian coast, establish state monopolies for the export of caviar, set up cooperative research programmes to conserve sturgeon species, establish annual total allowable catches and fishing regulations, and so on.

About 50,000 tonnes of kilkas are caught each year by the Industrial Fishing Company and fishing cooperatives using deep conical nets and air lifting with artificial lights as attractants. About 20,000 t of other species are caught by licensed cooperatives using beach seines and gill nets although a report in IRNA (27 March 2000) cites more than 16,000 t including whitefish (Rutilus), Mugilidae, Cyprinidae, "anchovy" (sic), bream (Abramis) and zander (Sander). An account of site selection for beach seining is given by Zanoosi (1993). Beach seining has been restricted to the period from sunrise to 8 p.m., and to 10 p.m. in Miankaleh (www.iranfisheries.net, downloaded 14 November 2006). The 1994-1995 finfish catch (excluding sturgeon and kilka) using gill nets, coastal purse seines and beach seines, was 17,000 t, perhaps over 22,000 t with the illegal catch included. About 87% of this catch is Rutilus frisii kutum, Liza auratus and Liza saliens (Annual Report, 1994-1995, Iranian Fisheries Research and Training Organization, Tehran, p. 37, 1996). Gill nets showed a 39% decline compared to the previous year and beach seines were 16% less. Rutilus frisii kutum comprised 53%, mullet 39% and others 8% of the total catch (Abzeeyan, Tehran, 6(5, 6):IV, 1995). The harvest from the southern Caspian Sea coast dropped 11% in the year 2000 from the same seven month period in the preceding year, to 7710 t, as a consequence of poaching, neglect of river maintenance, and substandard capture methods (IRNA, 10 May 2000). The catch in Golestan Province rose from 470 t in 2000 to 3278 t in 2005, attributed to artificial propagation, restrictions on beach seining, training about closed seasons and beach seine standards, increased fishing effort, and a favourable climate (www.iranfisheries.net, downloaded 14 November 2006).

There are 5 regional fishing centres namely Bandar Anzali with 14 fishing stations, Keyashahr with 12 stations, Babolsar with 13, Ashuradeh with 9 and Nowshahr with 9 (Iranian Fisheries Research and Training Organization Newsletter, 7:7, 1995). The Caspian Environment Programme (2001c) gives 15 stations for Bandar Anzali, 9 for Keyashahr, Babolsar, Ashuradeh and Nowshahr for sturgeon fisheries. Fixed gill nets are used with a standardised mesh. The Ashuradeh Peninsula, where more than half of Iran's caviar is processed, was threatened by the rising Caspian Sea in a 1991 radio report. A 1995 agreement between Iran, Azerbaijan, Turkmenistan, Kazakhstan and Russia gives each nation an exclusive fishing zone of 20 nautical miles from shore (Iranian Fisheries Research and Training Organization Newsletter, 7:7, 1995).

Inland freshwaters of Gilan are divided into three categories by Bakhshizod-Mahmoodi (1996): natural and impounded ponds, the Safid River reservoir, and wetlands. The ponds are used primarily for cyprinid and acipenserid culture, the reservoir is fished by seining, by spreading wheat grains in littoral areas to attract fish and by using the shemshad or shaghoul net (a giant dip-net), and the wetlands are fished by seining, by the salik or mashak (cast-nets), by the la'kesh (drifting gill net using one and two boats), by fixed gill nets, by the shemshad and by angling (for ordak mahi).

Pollution is an important factor in the ecology of the sea, from offshore oil drilling, ship discharges of oil wastes and contaminated water as well as garbage and even discharges from ship collisions, radiation from underground, non-military explosions and nuclear waste dumped in inflowing rivers (radiation levels are 100 times above normal (Time, 1 November 1993)), manure and pesticides from farming on the surrounding land mass, city waste water, sewage and garbage, industrial wastes including mercury and other heavy metals, discharges from water desalinating plants, extraction of minerals such as sodium sulphate, mirabelite and espomite, and untreated sewage (see Sardar (1979), Nuhi and Khorasani (1981), Coad (1980c), Khalili (1994), Raiss-Tousi (1999), Namazi (2000), Abaee (2001), Charamlambous (2001) and Laloei (2006) for Iranian problems; Anonymous (1988c), Edwards (1994), Specter (1994) and Kasymov and Rogers (1996) for former Soviet waters; Stone (2000b) is a recent, short general overview).

Data collected in 1991 showed the Caspian Sea received effluents comprised of 3000 tonnes of oil products, 28,000 t of sulphites, 315,000 t of chlorides, 200,000 t of tar and 25,000 t of phenols (Namazi, 2000). In Daghestani rivers, the same author records heavy metals, pesticides, phenol, arsenic, boron and selenium, among others, at 60-100 times the maximum permissible for fisheries. The oil industry is considered to be the main source of ecological problems in the Caspian Sea (Karpyuk, M. and Shavandin, V. 1996. Astrakhaners on the Caspian Sea. International Affairs, 42(1) from http://home.eastview.com/ia/42_01_15.htm). Prospecting uses blasting operations which have caused sturgeon deaths on more than one occasion. A single offshore well during its life releases into the water 30-120 tonnes of oil, 200-1000 t of sand, clay and other waste and 150-400 t of drilling mud paraffin fractions, baryta, lime, detergents, emulsifiers and lubricants. The ecology is affected 5-12 km from each well. The oil industry in the Caspian has reserves estimated at $4 trillion and a new oil rush will further contaminate the sea.

Charamlambous (2001) concludes that municipal wastewater from 11 million people is the primary pollutant in Iranian coastal waters. Industrial discharge accounts for 31%. of organic loading, the rest being municipal discharge. The most industrialised area is around Rasht with waste going into the Anzali Mordab. TACIS (2000c) reports that in Gilan, 32 of 36 major cities discharge wastewater untreated into a river and 89 of 90 industries discharge treated wastewater to a river. Ayati (2003) also reviews pollution in the mordab. Mirkou (2001) details agro-chemical usage along the Caspian shore comprising various fertilisers and pesticides.

Chlorinated pesticides have been used in anti-malarial campaigns throughout Iran and to eliminate pests on cotton, rice and other products in Mazandaran. Herbicides and pesticides are widely used in rice paddies. DDE, DDT, DDD, Lindane, Dieldrin, Eindrin and Kelthane have been identified in such rivers as the Babol and Chalus (Annual Report, 1995-1996, Iranian Fisheries Research and Training Organization, Tehran, p. 11-13, 1997). Ebadi and Shokrzadeh (2006) examined Rutilus frisii, Vimba vimba, Clupeonella delicatula and Liza aurata for lindane at Chalus, Babolsar, Khazarabad and Miankaleh but levels detected were less than the FAO/WHO recommended permissible intake and were no cause for public concern. Similar studies on DDT and DDE and on chlorobenzilate from the same sites and fish and levels were also less than the permissible intake (Shokrzadeh and Ebadi, 2005; 2006). The Chalus River also contains various heavy metals, such as lead, zinc, copper, iron, cadmium and chromium from mining activities (Annual Report, 1995-1996, Iranian Fisheries Research and Training Organization, Tehran, p. 18, 1997). Hashemy-Tonkabony and Asadi Langaroodi (1976) have shown the presence of DDE, DDT, TDE, Dieldrin, Lindane, Aldrin and Heptachlor in a wide variety of Caspian fishes in Iran. However, Ebadi and Shokrzadeh (2006) examined Rutilus frisii, Alburnus, Clupeonella and Liza species in Mazandaran for the organochlorine pesticide lindane and found levels in muscle tissues to be less than FAO and WHO recommended permissible intake and so were not a public concern. Rutilus frisii, Cyprinus carpio, Liza species and Acipenser stellatus were tested for DDT, aldrin and heptachlor with only the latter slightly elevated above standard levels at Hashtpar (Iran Daily, 11 January 2006). Phytoplankton diversity in the western Caspian Sea fell from 74 to 40 species, biomass from 8.7 to 2.1 g/ sq m and biomass of benthic organisms in coastal areas fell from 1724 g/ sq m in 1961 to 21 g/sq m in 1969 (Clark, 1986). These declines were noted particularly in the nursery grounds for sturgeon, Abramis brama, Esox lucius and Cyprinus carpio among other fish species. In the 1980s, catches of Abramis brama, Cyprinus carpio, Rutilus rutilus and Sander lucioperca fell by as much as 80% and Salmo trutta caspius and "shad" had almost disappeared. It was estimated that for 1985, 10,200 tonnes of oil products and 104,200 t of sewage were dumped in the sea. One-fourth (or 40 billion cubic metres) of all the wastewater in Russia enters the Caspian Sea and petrochemical factories alone release 67,000 t of waste annually (Anonymous, 1988c; Platt, 1995; Hamshahri, Tehran, 3 (639), 7 March 1995). Salinity increased as more water was taken for irrigation - two-thirds of the Terek and Kura flows did not reach the sea (Markham, 1989). In Iran, sewage is discharged into the Caspian Sea from coastal towns, and via rivers, from towns inland. Industrial solid wastes enter the sea through the larger rivers such as the Safid, Gohar and Siah as well as the Anzali Mordab complex. The use of agricultural chemicals such as fertilisers and pesticides has led to pollution, e.g. in Gilan Province 88,851 t of fertilisers were used in the year 1992-1993, an 18.7% increase over the previous year. A survey of 30 towns in Gilan shows that 80% of rubbish dumps are located by rivers, marshes or the coast (Hamshahri, Tehran, 3 (639), 7 March 1995). An estimated 200,000 fish were killed in the Kacha River, a branch of the Siyarud in Rasht, poisoned from a dump in the Saravan region which receives 390 t of rubbish daily. Heavy rains had washed poison into the river (Tehran Times, 7 October 1998). As many as 1000 trout (presumably mahi azad, Salmo trutta) died in the Kileh River in Mazandaran from release of wastes from a dairy manufacturer; sand extraction was also blamed for affecting fish populations (Iran Daily, 21 July 2005).

The biology of the Volga River and its effects on the Caspian ecology has been reviewed by Rozengurt and Hedgpeth (1989) and Pavlov and Vilenkin (1989). This river is of critical importance for marine fisheries. Fish production is less in the central and southern parts of the sea as nutrient supply comes from upwelling and circulation rather than a riverine input. However the Volga has effects even here, changing the Caspian Sea from its regime in the 1950s. Abstraction of water for irrigation, industry and household use caused salinity increases of about 0.2-0.3‰, increased aeration of deep layers and in their oxygen content down to 600-800 m by as much as 2-3 ml/l due to convection and thermal winter mixing, an increase in the euphotic zone to 50 m and depths open to total photosynthesis to 100 m, a decrease in organic matter and its vertical gradient, and an increase in wind-driven circulation and its effects on temperature and salinity layers. In the period 1956-1972, the Caspian Sea was transformed from a fishery based on valuable species (listed above) to one dependent on kilka which now occupies 80% of the catch (or 107 times the catch in 1930). Even including the kilka, catches in the 1970s were 245 x 10³ tonnes or only 37% of the 1913 catch. The catch of Caspian herrings (a complex of species in the family Clupeidae) ceased to exist commercially by the 1970s and in fact was banned. In 1967-1972 it was 0.6-2.1 x 10³ compared to 56-62 x 10³ in 1945-1953 or 82-307 x 10³ in 1900-1917 (Rozengurt and Hedgpeth, 1989). Moghim et al. (1994) report that, in the southern areas of the Caspian Sea, nearly 90% of the catch is composed of Rutilus frisii, Liza saliens and Liza aurata (with biomasses of 24,000, 7000 and 2400 t respectively and maximum sustainable yields of 7000, 2900 and 960 t  respectively). The Volga is a major pollutant of the Caspian Sea, carrying sewage, agricultural waste, PCBs, petrochemical wastes, tannery waste, etc. from a population base of 60 million people (Golub, 1992). In 1989, 40 million t of polluted wastewater entered the Caspian via the Volga River, more than a quarter of all the wastewater of Russia (http://www.oneworld.org/patp/pap_overview.html). A report in 1995 gives the volume of pollutants and industrial wastes entering the Caspian Sea each year as 11 billion cu m. Russia accounts for 50%, Azerbaijan 16% and Iran 11% (http://netiran.com/news/IRNA/html/950731IRGG17.html).

The Volga-Don canal in the former U.S.S.R. connected the Caspian Sea with the Black Sea in 1952 and formed an invasion route for various benthic organisms while others came in attached to boats transported by rail or were deliberately introduced (Kasymov, 1982). The molluscs Abra ovata and Mytilaster lineatus, two invaders, accounted for over 90% of the total benthic biomass. Invaders provided 95.1-99.3% of the total benthic biomass in the western part of the south Caspian Sea in 1976. East of the mouth of the Safid River, the Azov-Black Sea molluscs Abra ovata and Cerastoderma lamarcki accounted for 80% of total benthic biomass. In Gorgan Bay, 99.9% of the benthos fauna is comprised of invaders. The Volga is also connected to the Baltic and White seas via the White Sea-Baltic Canal opened in 1933 (Pavlov and Vilenkin, 1989).

The fisheries may well collapse if the 10 cm long ctenophore or comb jelly Mnemiopsis leidyi from the northwestern Atlantic Ocean enters the Caspian Sea via the Volga-Don canal in ballast water. It reached the Black Sea in the early 1980s and destroyed the local pelagic food chain (Travis, 1993; Dumont, 1995; Pearce, 1995; GESAMP, Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection, 1997; Negarestan et al., 2002; Kideys, 2002a; 2002b; 2003). The ctenophore eats fish eggs and larvae directly as well as zooplankton and crustaceans which are foods for fish (Bagheri et al., 2005). The Black Sea fish catches fell 90% in 6 years and the biomass of the ctenophore reached an estimated 900 million tonnes, ten times the world annual fish catch (or 1 billion t, about equal to the world fish catch - sources differ). The wet weight biomass of the whole Black Sea at times was 95% ctenophore. This suggestion of the mid-1990s was borne out, as detailed below. A continuing series of reports, magazine articles and studies on this invader are not all cited here.

The earliest report for the Caspian appears to be in 1995 by the Iranian Fisheries Research Organization (Bilio and Niermann, 2004; www.caspianenvironment.org/mnemiopsis/mnem_attach13.htm). The Islamic Republic News Agency (IRNA) on 12 May 1998 reported that a number of jellyfish had been observed in the Caspian Sea recently, presumably brought in the ballast of oil tankers, and its occurrence is documented by Esmaili Sari et al. (1999) and in numerous other studies by this author and co-authors. Various studies on the biology of the comb jelly have been carried in the Iranian Caspian Sea including, e.g. Movahedinia et al. (2002) and Yussefian (2002).

The kilka fisheries are now threatened by the comb jelly which spread through the entire sea by the year 2000. J. Muir (http://news.bbc.co.uk/hi/english/world/middle_east/newsid_1453000/1453117.stm, downloaded 30 August 2001), Kideys (2002b) and Kideys and Moghim (2003) report a 50% drop in kilka numbers with catches down from 3-6 t per night to half a tonne for one boat. A 50% decrease in kilka catches meant a minimum U.S.$15 million loss to the fishermen (Kideys and Moghim, 2003). Iran's kilka fishery fell from 85,000 t in 1999 to 15,000 t in 2004 and losses exceed $125 million (Stone, 2005a). Ghafar Zadeh and Honar Bakhsh (2008) summarise the economic consequences for Iran. This comb jelly can double in size in one day, reaches maturity in 2 weeks and then produces 8,000 young every day. Maximum abundance reached 5122 individuals per square metre in October 2001 and biomass 1024.5 g/sq metre in august-October 2002 (Roohi et al., 2003; Bagheri, 2004; 2006). The fisheries may recover somewhat after the comb jelly population collapses (Tidwell, 2001b). The website www.caspianenvironment.org/mnemiopsis/index. htm, downloaded 9 April 2003 and Dumont (2002) have extensive information on this problem and Stone (2002b) and IFRO Newsletter (29:4, 2001) confirm a severe depression in kilka and herring stocks. Beroe ovata, a comb jelly that preys on Mnemiopsis, is being cultured in Iran (Kideys, 2002b; Kideys et al., 2004; Rezvani Gilkolaei et al., 2005; Mirzajani, 2006; Mirzajani et al., 2007) and does not appear to feed on other organisms in the Iranian Caspian (Iranian Fisheries Research Organization Newsletter, 38:3, 2004). Reproduction and growth are slower, and mortality higher, than in the Black Sea, due either to the lower salinity in the Caspian Sea water or damage to individuals during transportation for the experiments. If this comb jelly fails to control Mnemiopsis, the introduction of the exotic American species, the butterfish (Peprilus triacanthus), known to feed on ctenophores has been advocated but this fish could also feed on other fishes (Harbison, 2002; Bilio and Niermann, 2004). The complex politics of the nations surrounding the Caspian have prevented the introduction of Beroe (Stone, 2005a).

The Kara Bogaz Gol ("Black Throat Bay"), an eastern arm of the Caspian Sea in Turkmenistan, is 160 km long by 140 km broad (18,389 sq km) but only 2-3 m deep. It acts as a salt precipitator. This water body was blocked off by a dam to conserve the water lost in it by evaporation in 1980. The Caspian Sea has a net annual water deficit of 15 cu km with 5 cu km being lost through the Kara Bogaz Gol alone (Rich, 1982; 1983). However this resulted in salts being spread by the winds, ruining fish spawning grounds and fish farms in the Caspian basin, and ultimately would lead to the salinisation of the Caspian Sea. A dike has now been constructed to allow some flow into the Kara Bogaz Gol and allow the flushing effect to operate. The refilling process over 3 years prevented a 35 cm rise in the Caspian Sea level (Dumont, 1995). Use of this water body to reduce level rises in the Caspian Sea and prevent flooding has been proposed (Wardlaw, 2001). Fish which enter the salty Kara Bogaz Gol lose their swimming capacity, become blind and thrashing about often come to lie on the shore. Birds eat them but those that are missed become salted and dried and may be preserved for a year or so. The Turkmenistan government re-established natural flow into the Kara Bogaz Gol in 1992 because of the Caspian Sea level rise (Zonn in Glantz and Zonn (1997)).

The Caspian coastal plain in Iran runs for almost 650 km from Astara (38°26'N, 48°52'E) in the west to Bandar-e Torkeman (= Bandar-e Shah) (36°56'N, 54°06'E) in the east. This plain has a width of about 25-32 km, but is as narrow as 2 km in places, although it opens out in the east. The Alborz Mountains are almost 1000 km long, on average less than 100 km wide but very high. Damavand reaches 5766 m - an estimate - at 35°56'N, 52° 08'E and is the highest of any mountain to the west of it in Europe and Asia. It has a continuous snow cover. There are persistent snow fields and Alam Kuh at 4849 m has small icefields. The north or Caspian slope is very steep and streams tend to be short and torrential, fed by snow melt and year-round rain. However there are some longer rivers and the principal ones are detailed below. There are about 128 small to large rivers along the Caspian shore. Nümann (1966) gives some limited biological, chemical and physical data on these streams based on spot recordings. Surber (1969) gives values of total alkalinity and calcium-magnesium hardness for a number of streams and reservoirs along the Caspian shore. Most were moderately to relatively hard and therefore productive for aquatic organisms such as insect larvae on which fish feed. The Caspian Environmental Programme (2001b) gives an overview of habitats and biodiversity along this Iranian shore. Environmentally managed areas are listed along with factors affecting their status under the headings of development, drainage, land use alteration, pollution, destruction of vegetation, over-grazing, mining, hunting and fishing, exotics, dams, and roads. Of 123 fish species only 10 or just over 8% are protected with one protected species on the verge of extinction.

Most rivers along the Caspian shore have less than 30% of their discharge in the two wettest months and 40% in the six driest months so discharge is well distributed through the year. In contrast, the Gorgan River at the eastern end of the Caspian basin has 70% of its discharge in the two wettest months, figures comparable with drier areas such as Azarbayjan at 50-60% and the Zayandeh and Kor rivers at 40-60%. Annual discharges can vary markedly, e.g. the Lar River had 545 mm on its basin area in 1949-1950 and 1560 mm in 1950-1951 (Ghahraman, 1958).

The Aras (= Araxes or Araks) is a tributary of the Kura River of Azerbaijan. The Kura rises in Turkey and is 1510 km long. The Aras forms the border between Iran and the former U.S.S.R. (now Azerbaijan and Armenia) for 430 km and has its source near Erzurum (39°55'N, 41°17'E) in Anatolia and the headwaters of the Euphrates River. Its total length is 1072 km. The Aras can be wide and meandering with braided channels and backwaters. Depth range of the Aras is 0.5-4.0 m, average 2.5 m (Zakeri, 1997). The Araxes or Aras Dam was a joint Iranian-Soviet project on this river. Iranian authorities stocked the dam with 1.8 million fingerlings (species not specified) weighing over 10 g each in 1997 to enhance fish farming (Islamic Republic News Agency, 29 December 1997). Akh Gol occupies 600 ha at 820 m in the Aras River valley in northeastern Iran (Scott, 1995). It comprises a small brackish lake with associated marshes and springs and rains to the Aras 5 km away. The area is being converted to agriculture and the lake is being drained. Principal tributaries of the Aras in Iran are the Qareh Su (= black water, draining easily eroded, volcanic soil) draining from the Kuhha-ye Sabalan at 4810 m (38°15'N, 47°49'E) near Ardabil (38°15'N, 48°18'E) and the Qotur River draining past Kuh-e Zaki at 3079 m on the Turkish border through Khvoy (38°33'N, 44°58'E) to the Azerbaijan border near Jolfa (38°57'N, 45°38'E). The Aras and the Safid are two of the three largest rivers in Iran (with the Karun River of Khuzestan). The Kura-Araks basin encompasses 225,000 sq km of which 28,000 sq km or 12.4% is found in Iran (Gleick, 1993). Azerbaijan discharges 303 million cu m of waste into the Caspian Sea annually according to Golub (1992), presumably through the Kura and other major rivers.

Derzhavin (1929a) gave an interesting account of the formation of a new channel of the Aras north of the Iranian border in 1896 which led to the freshening of the Kyzylagach Bay. This favoured migrations of fishes into the Kura River. However, irrigation schemes on the Mugan steppe severely reduced catches as well as causing salinisation of soil. Water abstraction prevented entry of adequate numbers of sturgeons onto the Kura spawning grounds. This type of water usage is paralleled along the Caspian shore in Iran with deleterious effects on a variety of sedentary and migratory fish species.

The Safid (= Sefid or White from its sediment load, up to 60 g/l) River is the only one to completely pierce the Alborz Mountains and has a considerable basin (54,100 sq km) on the plateau. Various sources give differing accounts of its length, up to 800 km. The Safid has the greatest mean discharge of Iranian Caspian rivers, over three times that of the Heraz, the next most important. In flood the Safid discharge is twice that of the Karun, but its minimum is less than a tenth, because the Karun drains a greater area with higher elevations and a more extensive snow pack. The Safid discharge is 4000 cu m per second at maximum, falling to only 15 cu m per second. An average discharge is 182.17 cu m per second. There used to be two freshets before the dam was constructed at Manjil, one fed by spring snow melt in March-May and one by rainfall in the autumn. The rise in water levels and increased sediment load attracted sturgeons, in particular Acipenser persicus. The catch of this species and A. gueldenstaedtii in the Safid River area reached 733,127 kg in 1927/1928 representing 46,500 fish and a caviar yield of 120,958 kg (Vladykov, 1964).

The width of the Safid River varies from 100 to 250 m and depth from 2 to 8 m. The average instant yield is 128.79 m/sec, range 76.5-288.5 m/sec. The average annual yield is 3,998.4 million cu m (Zakeri, 1997).

The Safid is formed from the Qezel Owzan from the west and the Shah River from the east which meet on the plateau and flow through a narrow gorge. This gorge is dammed by what was named the Shahbanou Farah Dam at Manjil (now the Safid or Manjil Dam) (dam height 106 m, length 425 m; reservoir 1860 million cu m, surface area 56 sq km maximum, 14 sq km minimum, maximum depth 80 m, minimum 30 m, summer temperature 24°C, winter 7°C, pH 7.8, 31 g/l turbid materials, Cl^- 229 mg/l, SO₄ 178 mg/l). Strong water level fluctuations prevent the development of a belt of vegetation and the heavy sedimentation inhibit a bottom fauna. Khodjeini and Mohamed (1975) detailed the rate of sediment accumulation in this dam, 757 cu m/sq km/year, evidence of severe erosion of a devegetated drainage basin. The reservoir was half filled with sediment after only 20 years despite an expected life span of 100 years. The reservoir is apparently drained at intervals to remove some of the accumulated sediment. This would severely affect littoral spawning and feeding habitats for fishes. Nümann (1966, 1969) gives details on the limnology of this reservoir. The dam decreased turbidity in the river, raised water temperatures at the river bed in summer and caused marked diurnal temperature changes. This prevented ascent of Salmo trutta to the upper reaches and the dam itself prevented ascent of Rutilus rutilus. Nümann (1966) recommended introducing Sander lucioperca, Acanthobrama terraesanctae (a Levantine species) and cichlids to the reservoir.

Sarpanah et al. (2004) found 45 species and subspecies in the Safid River basin with 29 of these economically important. Thirteen species were migratory, 11 species estuarine and the rest resident. Thirty-six species were recorded as endemics (presumably native) with rest exotics and migrants. The Boojagh National Park near the estuary of the Safid River in Gilan has 25 species and subspecies of fish (Khara et al., 2004).

Lower dams on the Safid, such as the Tarik (10 m high) and the Sangar (3 m high), divert water for irrigation purposes on the Gilan plain, the former through a 16.7 km long tunnel.

The Safid breaks up into distributaries near its mouth and its flow is carried off into a complex of canals and irrigation ditches. The Safid has changed its delta several times, (Vladykov, 1964). In 1911 it shifted 2-3 km east from the fishing post of 12 Bahman to Hasan Kiadeh. An account in Farsi on the Safid River is given by Wossugh-Zamani (1991b).

The headwaters of the Qezel Owzan lie in Kordestan, near the Iraqi border, and so drain part of the northern Zagros Mountains as well as areas near Lake Orumiyeh such as the Kuh-e Sahand (37°44'N, 46°27'E), mountains near Hamadan (34°48'N, 48°30'E) and the southern slopes of the Alborz Mountains. The Qezel Owzan is about 550 km long. The Taham Dam project 12 km northwest of Zanjan lies in the Qezel Owzan basin on the Taham Chay. This dam is to be 120 m high with a crest length of 450 m and a capacity of 82.7 million cu m. The fish fauna behind the earth dam at "Maljiq", 50 km southwest of Hashtrud in the upper Qezel Owzan basin, suffered severely in the drought of the year 2000. Twenty-five tonnes of fish died after the reservoir dried up (www.irna.com/newshtm/eng/09151847.htm, IRNA, 30 July 2000).

The Shah River is much shorter (ca. 175 km) than the Qezel Owzan and drains the southern Alborz as far east as Takht-e Soleyman at 4819 m (36°22'N, 50°58'E).

The 500 ha Bandar Kiashahr Lagoon (= Bandar-e Farahnaz) Ramsar Site (World Conservation Monitoring Centre, 1990) at 37°25'N, 49°19'E east of the mouth of the Safid Rud was a freshwater coastal lagoon and swamp fed by two streams from the Safid Rud to the west and draining to the Caspian Sea via a channel to the north. The recent rise in Caspian Sea level has converted this area into a bay of the sea as it was in the 1950s before the fall in sea level (Khan et al., 1992). The lagoon bed is sand and mud and the water was oligotrophic except near the marshes to the west. There were reedbeds of Phragmites communis, Typha and Juncus, now restricted to the extreme west end. There were several factors affecting this habitat including a fishery with a fish-processing warehouse, grazing, reed cutting, irrigation abstraction and recreational activities. It was an important spawning and nursery ground for fishes (effects of recent changes unknown) and is still an important centre for commercial fishing.

The Heraz River drains the Alborz east of Tehran and has a number of longitudinal tributaries in the mountains. These depend on snow melt and are cold even in summer. Fishes are reported to be present in these high streams, but were not easily caught. The Heraz debouches onto a plain and splits up into distributaries. It is polluted from rainbow trout farms (Kazemzadeh Khajuie et al., 2002) and heavy metals (lead and cadmium) are present in fish (Riahi Bakhtiyari, 2001; 2002). The Tajan or Tadjan River was studied by Ro(o)shan Tabari (1995; 1996) who reported on its hydrology and biology. Its mouth lies at 36°49'N, 53°05'E. The maximum flow is in April, decreasing from May onward. In April 1989 flow was 45 cu m/sec falling rapidly to 0.11 cu m/sec in June. Over 70% of the fishes are anadromous with sturgeons being the most important species (Acipenser persicus, A. gueldenstaedtii and Huso huso). Salmo trutta is the most important species in the upper reaches. Other species found in this river are Cyprinus carpio, Alburnus sp. (presumably Alburnus alburnus), Capoeta capoeta, Barbus capito, Vimba vimba, Alburnus chalcoides, Rutilus frisii, Rutilus rutilus, Liza sp., Gobiidae, and Esox lucius. Rural, agricultural and industrial pollutants are found in the Tajan and affect the fishes along with dams and other physical obstacles, sand removal and overfishing. The Shahid Rajaee Reservoir Dam, inaugurated in 1997, is found on this river 41 km south of Sari (http://netiran.com/news/IRNA/html/951016IRGG15.html and http://netiran.com/news/IRNA/current.html#HLNO4). The Independent (London) reported on 13 July 1994 that tens of thousands of fish died in this river after poachers poured poison into it about 9 miles (14.4 km) above the estuary. Dead fish covered the river bed for 6 miles (9.6 km).

The south-eastern corner of the Caspian Sea receives two major rivers, the Gorgan and the Atrak or Atrek (ancient Sarnois). Their courses are roughly east-west and parallel each other with the Atrak forming part of the border with Turkmenistan. The Atrak is 495 km long (with 145 km of this in Turkmenistan; Nezami et al. (2000) state 715 km for the Atrak) and the Gorgan 240 km. The Gorgan drains 10,200 sq km and has an average discharge of 9.39 cu m per second (cf. Safid River with 182.17 cu m per second; the Chalus River, directly north of Tehran, has a discharge of 12.65 cu m per second). The Voshmgir or Sangarsavar Dam at 37°12'N, 54°45'E on the Gorgan stores 60 million cu m of water. The water level fluctuates markedly, banks are steep and there is little emergent vegetation. The Golestan Dam (same as preceding?) is 20 km north of Gonbad-e Qabus on the Gorgan River and has a capacity of 86 million cu m. Keivany et al. (1990; http://gause.biology.ualberta.ca/Keivany/bsc/html - 1996) report an irregular pH range for the Gorgan River from 6.3 to 7.9 with an average of 7.1. Temperature range was 8 to 33°C. Conductivity varied greatly from 667 to 10,000 µM/cm, with an average of 875 µM/cm. Chlorides, especially sodium chloride, were the most abundant soluble salts. Total dissolved solids varied from 21 mg/l to 4300 mg/l in an inverse relationship with water volume. Water volume at the dam inlet varied from 2 to 75 m³/second and almost 52% of the sediments entered the dam during a high flood. Water quality was assessed as polluted. The major fish species were Cyprinus carpio, Barbus barbus (sic - possibly B. capito), Alburnus spp., Cobitis taenia, Gambusia affinis, and Carassius carassius (sic - presumably C. auratus). A fish kill noted by Coad (1980c) in 1978 was attributed by local informants to careless insecticide spraying on fields neighbouring the Gorgan. Newspaper and radio reports variously stated that 200 barrels of a highly toxic chemical spilled into the river when a truck overturned and that the chemical, identified as Turbidan from the Trintext chemical plant, was dumped by a technician commissioned to get rid of the waste product (Kayhan International, 7 May 1978).

The Atrak headwaters are close to those of the Tedzhen basin. The Atrak basin comprises about 40,000 sq km. The Atrak is only about 10-15 m wide and about 0.5 m deep over much of its lower course. It only reaches the Caspian Sea during floods. A tributary of the Atrak from Turkmenistan is the saline Sambar River, about 203 km long. Petr (1987) reports that efforts were being made to divert this river so as to increase the water quality in the Atrak. The fresh section of the Atrak has a conductivity of 2362 µS and the saline section 23,500 µS. The Caspian Sea off the Atrak River is an important fishery economic zone. Gasan-kuli or Hasan Kuli is a town in Turkmenistan near the Iranian border referred to in fishery reports from this area. The catch of Rutilus rutilus, Cyprinus carpio and Sander marinum was nearly 1.44 x 10⁴ tonnes with only 1.9% being accounted for by Clupeonella cultriventris. However by 1972 the catch of the commercially important species had declined to 1.5% and the less desirable Clupeonella had increased to 5.73 x 10⁴ t or 98.3% of the catch. The causes were reduction in the Atrak runoff through irrigation withdrawals, pollution from agriculture, overfishing in the sea and the drop in sea level. Flows of the Atrak did not reach the sea in 1984, 1986, 1990 and 1991and spawning of species using the lower reaches did not occur (Caspian Environmental Programme, 2000).

There are 5 lakes along the Atrak, fed by the river, which have been recently dyked to improve water retention. Their fauna is dominated by native cyprinids. The lowest lake is saline and they range in size from 400 to 2500 ha.

The lakes Alagol or Ala-Gol at 37°21-22'N, 54°35'E, Ulmogol, Alma-Gol or Ulmagol 37°24-25'N, 54°38-39'E and Ajigol or Adji-Gol at 37°24-25'N, 54°40'E comprise a Ramsar Site (World Conservation Monitoring Centre, 1990; Scott, 1995) near the frontier with Turkmenistan just east of the Caspian Sea. Alagol occupies 1400 ha (Scott (1995) states 900 ha) and both Ulmogol and Ajigol 200 ha (Scott (1995) states 280 ha and 360 ha respectively). The Alagol Lake is slightly saline with a mud and sand bottom. It is fed by springs, seepage and precipitation and may dry out completely in summer. It overflows westwards when full. Vegetation is sparse with Juncus, Carex and grasses mainly in the northeast and small patches of Phragmites communis. It is oligotrophic and vegetation poor. The other two lakes have seasonal fresh water fed by precipitation and have a mud and clay bottom. They are eutrophic and water levels vary greatly so that they may dry up completely. Ulmogol has little vegetation such as Juncus, the duckweed Lemna, Phragmites communis, Alhagi and algae while Ajigol has extensive Phragmites reedbeds at its eastern end and abundant submerged vegetation. Fishing occurs in the lakes and the habitats are affected by cattle grazing and reed cutting. Water is abstracted for irrigation and for a fish hatchery. In Alma-Gol and Ala-Gol, 90.91% and 82.18% of the total frequency of fishes was comprised of exotic species. Hemiculter leucisculus was the most frequent in Alma-Gol (58%) and Adji-Gol (16.82%) and Carassius auratus in Ala-Gol (77.6%). Other exotics were Gambusia holbrooki, Pseudorasbora parva and Cyprinus carpio (Patimar and Kiabi, 2005). Patimar (2008) details the environment of these lakes and lists six native species (Alburnus alburnus, Barbus capito, Capoeta capoeta, Cyprinus carpio, Rutilus rutilus and Atherina boyeri) and 4 introduced species (Carassius auratus, Hemiculter leucisculus, Pseudorasbora parva and Gambusia holbrooki), variously distributed among the lakes.

The Qareh Su (= Gharesoo) is another river entering the Gorgan Mordab. In its upper reaches it has a rocky bed and a fauna of Nemacheilus malapterurus, Capoeta capoeta and Alburnoides bipunctatus, resembling the grayling zone of Europe. The central part of the river dries up (the barbel zone) while the lower river (bream zone) is brackish from gulf input, has high temperatures and pollution. This lower zone has Carassius auratus, Alburnus alburnus, Cyprinus carpio, Pseudorasbora parva, Gambusia holbrooki and Gasterosteus aculeatus with Atherina boyeri, Neogobius kessleri, Neogobius melanostomus, Neogobius fluviatilis, Knipowitschia caucasica, and Liza saliens feeding in the estuary, and Acipenser stellatus, Alburnus chalcoides, Cyprinus carpio, Rutilius rutilus and Vimba vimba migrating into the river for reproduction.

Incheh Borun Lake at 37°13'N, 54°30'E is a small and isolated freshwater body of 50 ha about 40 km north of Gorgan. Lake Bibishervan at 37°09'N, 54°52'E and Lake Eymar at 37°08'N, 54°52'E are two more small isolated freshwater lakes occupying 300 ha and 250 ha respectively. All three lakes lie on a cultivated plain. The fish faunas of these lakes are unknown.

The Golestan National Park lies between Bojnurd and Gonbad-e Qabus and is divided by the Tehran-Mashhad highway. The Iran Nature and Wildlife Magazine (volume 3, 1999; downloaded from its English website) states that fish in the Doogh River include rainbow trout and Umbra krameri (sic), both exotics. The latter species is an error of translation from Farsi to English of common names (B. Kiabi, pers. comm., 23 February 2000). A description of the park is given by Kiabi et al. (1994).

The Anzali (= Enzeli or Pahlavi) Mordab (37°26'N, 49°25'E) is a freshwater to brackish lagoon (Firouz, 1968b) separated from the Caspian Sea by a sandy barrier about 1 km wide. The more modern term is "talab" (= pool or marsh, which lacks the association with death) but the older literature refers to mordab and the term is still in common use. It is surrounded by ab-bandans such as the Selke Ab-bandan of 360 ha at 37°24'N, 49°29'E which is protected as a Wildlife Refuge. Ab-bandans are a feature of the Caspian coastal plain, being a shallow and artificial freshwater impoundment managed in winter for duck hunting and in summer as an irrigation reservoir. The Anzali Mordab complex of 15,000 ha is a Ramsar Site and this includes the whole mordab, the Siah-Kesheem marshes, Selke Ab-bandan and several other ab-bandans. The main mordab comprising open water is 26 km long and 2.0-3.5 km wide encompassing about 11,000 ha. Reed beds extend the eastern limit by a further 7 km. The Siah-Kesheem (or Siah-Keshim) Protected Region has a lagoonal surface area of 4500 ha (Khara, 1994; 6700 ha in Scott, 1995) and is about 12 km long by 4.5 km wide. It lies to the southwest of the main mordab, of which is was probably once part, and is fed by the Esfand River. Note that Khan et al. (1992) state that the Anzali Mordab is unprotected except for the Siah-Kesheem Protected Region and the Selke Ab-bandan of 360 ha. A description of the Siah-Keshim Protected Area is given by Riazi (1996) and of the wetland generally by Monawari (1990). Important fishes are listed as Sander lucioperca, Cyprinus carpio, Silurus glanis and Esox lucius (Iran Nature and Wildlife Magazine, 5, www.neda.net/inwm/no.5/english/pre_sites/pre_sites01.html, downloaded 8 March 2000).

The main mordab is drained by the Sowsar Roga, Pir Bazar Roga, "Raste-Khaleh" (? Rasteh Kenar) Roga, Nahang Roga and Pahlavi or "Koulivar" (? Kolver) Roga over a distance of about 4 km to the Caspian Sea. Warm, dense and saline sea water is able to penetrate up these effluent rivers for as much as 10 km, which generally have low flow because of water abstraction and seasonally low precipitation, because of the rise in sea level since 1977. Fresh water flows across the surface of the saline water mixing at depths of 0.5-2.0 m. Salt water contamination is always a danger as more water is abstracted in this heavily populated and farmed area (Kimball, 1973; Kimball and Shayegan, 1973; Sharifi, 2006). Abdolmaleki (1994) gives some data on the benthic macrofauna of this lagoon. Hosseinpour (1995) surveys the zoobenthic resources of the Siahdarvishan and Pasikhan, two principal rivers which enter the lagoon. Other entering rivers are the "Bohambar, Chakoor and Esfand".

Forest clearance around the mordab, rice production and other agriculture, dams and weirs on inflowing rivers, river bed erosion through decline in Caspian Sea level, influx of pesticides such as Diazinon (Talebi, 1998), Paraquat, Glyphosite, and chemical fertilisers, domestic and agricultural sewage, excessive aquatic plant growth and natural decay of vegetation (Nezami and Khodaparast, 1996; Filizadeh and Khodaparast, 2005), phytoplankton blooms, some toxic (Nejatkhah et al., 2003) anionic surfactants (Dadaye Ghandi et al., 2005), siltation from deforestation of feeder streams, introduction of exotic species of fish and plants such as Azolla (Iran Daily, 2 November 2006), grazing for livestock, reed cutting for mats, fences and building materials, and a high urban population growth of 4.6% per year, all affect the habitat and the marsh is highly eutrophic. These factors also contribute to the fall in commercial fishing success. In the 1930s the catch was dominated by the valuable Rutilus frisii kutum but in the 1990s the catch was 50-75 times lower and the mordab now has a low value to fisheries. The situation is compounded by the absence of effective fishery management. The introduced Carassius auratus dominates catches. The mordab was a principal breeding ground for Rutilus frisii kutum, Abramis brama and Cyprinus carpio, and to a lesser extent Sander lucioperca, and was an important habitat for Esox lucius. Fish kills occur, more than 100,000 dying in August 1997 due to a lack of oxygen after "torrential rain and the growth of aquatic herbs had created an unsuitable environment" (a Reuters report) and more fish died in 2005 (Iran Daily, 21 August 2005).

The bottom of the shallow west basin was completely covered by perennial submerged vegetation in the early 1970s (Chara, Nitella, Ceratophyllum, Myriophyllum, Hydrilla, and Vallisneria). Water chestnut (Trapa natans) was the predominant floating plant and covered the central basin in 1966. The Caspian lotus, Nelumbium caspium is found all across the lagoon and is a significant part of the standing stock. Phragmites, Sparganium and Typha are emergent plants which engulfed open water. Reeds were formerly cut extensively for building purposes but are now replaced by sheet metal and cement blocks. Falling Caspian Sea water level and eutrophication from domestic sewage and fertilizers aided plant growth. The fern, Azolla filiculoides, was introduced as an additive to cattle feed and rice cultivation from the Philippines in 1986. It soon entered the mordab from the rice fields and mats up to 20 cm thick covered much of the open water in 1991 (Holčík and Oláh, 1992). Dense growths of macrophytes have contributed to declines in commercial fish catches as spawning grounds have decreased, eutrophication is enhanced, and light penetration is decreased and so oxygen declines. There are about 200 sq km of marshes and 30 sq km of shallow open water fed by rivers from the Alborz Mountains. The area of open water in 1989 was only 22.5% of that in the late 1930s (Holčík and Oláh, 1992). However the rise in Caspian Sea level since 1978 has led to a salt water intrusion during the summer months when the Caspian level is at its highest and freshwater input from rivers is at its lowest. Deeper and more saline water may well inhibit plant growth in the future (Khan et al., 1992).

The marsh is only a few metres higher than the Caspian Sea and had a maximum depth of 2.5 m in the early 1970s. Caspian Sea level fluctuations have serious effects on the level of the mordab and hence its utility as a habitat for fishes. The optimum level for the fish industry in general in the Caspian basin is given as -27±1 m (Mandych, 1995). The rise in Caspian Sea level since 1977 is gradually returning the mordab to its supposed, natural brackish state and may improve the fisheries situation which had declined over the last 50 years. Emergent and submergent aquatic macrophytes were decreasing and such fish as Atherina boyeri, Alosa caspia, Liza aurata, Syngnathus abaster and Clupeonella cultriventris were increasing in numbers since 1989. However the fishery will require extensive engineering and management innovations to recover.

Hydrorybproject (1965), Kimball (1973), Kimball and Shayegan (1973), Kimball and Kimball (1974), Hagh-Panah (1992), Holčík and Oláh (1992) and Caspian Environmental Programme (2001c) give details of the limnology of the marsh. Water temperatures vary seasonally from 0° to 28.8°C (average about 16ºC) and dissolved oxygen from 0 to 17.5 mg/l for example. Phytoplankton blooms have killed fish in the mordab, e.g. on 5 June 1997 when dissolved oxygen in the western part was at 0-0.2 mg/l and hydrogen sulphide was at 2.0-2.5 mg/l (Iranian Fisheries Research and Training Organization Newsletter, 17:7, 1997).. Conversely, low phytoplankton populations have probably resulted in lowered fish catches. High water temperatures and chlorophyll inactivation through high light levels reduce the numbers of phytoplankton and hence zooplankton, on which fish feed, also decline. Higgins (1973) found that DDT levels in sturgeon, sturgeon caviar, Cyprinus carpio and Rutilus frisii taken near Anzali were not hazardous to humans in flesh (0.2-1.8 p.p.m.) or in caviar (0.05 to 2.5 p.p.m.), both less than the limit for edible fishes set by the U.S. Food and Drug Administration at 5 p.p.m., but that the level in the caviar was a serious threat to sturgeon reproduction. DDT was more concentrated in the eggs because of their fats and oils in which DDT is more soluble. Certain heavy metals, lead and silver, were potentially harmful to the fishes also. Pourang (1995, 1996), Amini Ranjbar (1998), CEP (2001a) and Sartaj et al. (2005) describe heavy metal concentrations (lead, chromium, copper, cadmium, zinc, manganese and nickel) in fish, surficial sediments and various macroinvertebrates of the Anzali wetland. Levels in Carassius auratus and Esox lucius were below recommended levels for human consumption. Carassius auratus, Cyprinus carpio, Esox lucius and Hypophthalmichthys molitrix in the Anzali Mordab have zinc (5.39-27.98, mean 17.28 p.p.m.), cadmium (0-0.08, mean 0.0251 p.p.m.), cobalt (0-1.67, mean 0.6935 p.p.m.), lead (0.11-2.95, mean 1.04 p.p.m.) and mercury (0.113-0.63, mean 0.3 p.p.m.) in their muscle tissues (Annual Report, 1995-1996, Iranian Fisheries Research and Training Organization, Tehran, p. 46-47, 1997). Nadim (1977) found the highest mercury levels in Caspian Sea fish were 0.51 and 0.36 mg/kg in Rutilus frisii and Esox lucius respectively with the lowest in Liza aurata at 0.07 mg/kg. As the acceptable limit was 0.5 mg/kg, mercury contamination in fish was not considered a problem. The lowest zinc concentration was in H. molitrix, the highest lead concentration was in C. carpio and the highest cobalt concentration in C. auratus but concentrations were less than those set by WHO as significant. Södergren et al. (1978) reported on pollution with organochlorines in Esox lucius from the mordab and found this predatory fish to have accumulated the DDT metabolite p,p^'-DDE, suggesting that this occurred over considerable time and was not a recent event. DDT did not appear to be incorporated in the pelagic food chain, although it has been used for agriculture and vector control problems. Most DDT probably attaches to clay and soil particles and settles out on the mordab bottom. These authors also recorded DDT from sturgeon species and their eggs in Iranian waters. Pollution continues to be a problem in this heavily populated, industrial and farming region. Heavy rains in October 1995 swept industrial wastes including heavy metals such as lead and zinc, agricultural waste and domestic sewage into the mordab. A fish kill resulted as evidenced by the mordab being covered with floating dead fish. The kill was attributed to the heavy metals and to oxygen depletion (http://netiran.com:80/news/IRNA/html/941029IRGG01.html).

Mercury concentrations in fish and fishermen's hair were studied from the Caspian shore by Zolfaghari et al. (2008). The mean hair mercury concentration was below the WHO threshold level and there was a weak correlation between number of fish meals per month and mercury levels. Levels in Vimba vimba, Rutilus rutilus, R. frisii, Liza spp., Carassius auratus and Esox lucius exceeded US EPA guidelines.

Amini Rad (2001) assesses the socio-economic importance of fisheries in Bandar Anzali. Fishes are very popular food items there with an average consumption of 11.3 kg, 70% more than in the rest of Iran. White fish (safid mahi, Rutilus frisii) was 1.5 times more expensive than mullets (Mugilidae), 2.6 more than other species and almost 28 times kilka.

Gorgan (= Asterabad or Astrabad) Bay (36°40'N, 53°50'E) is 56 km long by 16 km long and is brackish (8.7-10.0‰) because of input from rivers although Bayrami et al. (20030 give 16 p.p.t. The bay encompasses about 400 sq km. A general description is given by Zanusi (1995) who considers it to be the second richest resource for caviar in the Caspian Sea after the Volga River. The Caspian Environmental Programme (2001c) gives an average surface water temperature of 19.1ºC, oxygen from 2.4 to 11.1 mg/l, pH 8.0-8.5 and total dissolved solids 11.23 mg/l in February to 15,052 mg/l in March. The bay's ecology has been changed by the recent rise in sea level which resulted in storm surges over the sand bar between it and the Caspian Sea. The construction of the Voshmgir Dam on the Gorgan River in 1970 also had an effect, reducing the amount of fresh water to the river mouth which provided spawning areas for Cyprinus carpio and Rutilus rutilus. Over 40% of the total sturgeon fishing in the Caspian Sea is centred on Bandar-e Torkeman. There is also a black market in sturgeon products. Authorised fishing resources shrunk by 33% from 1993-1994 to 1994-1995 through unauthorised fishing, lack of controls and decrease in controlled sturgeon reproduction. The authorised catch in 1994 for the region from the Neka River to the Turkmenistan border was 1500 tonnes and the unauthorised catch was probably of similar size. The caviar production was 57,000 kg.

The bay once had a valuable Rutilus rutilus fishery with an annual catch of 4000 t per year about 20-30 years ago but this has disappeared (Petr, 1987). The bay is now dominated by Mugilidae (CEP, 1998). The catch in the Voshmgir reservoir was 60 t in 1986 although it may improve with stocking programmes. Lalouie (1993) surveyed the hydrobiology of the bay and found an average pH of 8.3, similar to the sea proper as were alkalinity and total hardness. Water temperatures ranged from 5°C to 30°C annually. Pollution from urban and industrial sewage and pesticides is present.

Gorgan Bay is believed to be an important nursery ground for Liza aurata, a major food fish, although an exotic. Cage and pen culture operations in the bay may result in escapes of exotics that could affect native species. On three separate occasions, cages capsized in storms releasing millions of Oncorhynchus mykiss fingerlings (www.ramsar.org/ram_rpt_37e/htm, downloaded 4 May 2001).

The area of the Miankaleh Peninsula, Gorgan Bay and the nearby freshwater Lapoo-Zaghmarz Ab-bandans is designated as a Ramsar Site (World Conservation Monitoring Centre, 1990). The Miankaleh Wildlife Refuge encompasses 81,180 ha and is part of the Miankaleh Protected Region (97,200 ha). Jones (www.ramsar.org/lib_dir_2_3.htm downloaded 14 April 2000) gives 68,800 ha for the Wildlife Refuge. The Miankaleh wetland may encompass 40,000 ha, not the larger figures as originally designated (Khan et al., 1992). The bay has a sand and mud bottom and is oligotrophic. There are extensive marshes along the southern and eastern shores which flood in fall and winter. These marshes are eutrophic from agricultural runoff and stream and irrigation channel inputs. The bay vegetation comprises principally glasswort (Salicornia), sedges (Carex) and rushes (Juncus) with some small reedbeds of Phragmites communis. The ab-bandans have extensive reedbeds of Phragmites communis with stands of reedmace (Typha) and abundant submerged vegetation. Several factors will affect the ichthyofauna including irrigation requirements limiting freshwater flow into the bay and ab-bandans, a fish processing plant at Ashuradeh with associated wastes, a new road along the peninsula which facilitates access and potentially increased pollution and poaching, reed cutting, heavy livestock grazing, agricultural wastes, aquaculture ponds using exotics, fishing by local people and a proposed nuclear power plant. The whole area is an important nursery and breeding ground for fishes. The ab-bandans are not protected although they are within the Ramsar Site. The two shallow ab-bandans occupy 950 ha at 36°50'N, 53°17'E northwest of Behshahr. They are fed by irrigation ditches and drain east into Gorgan Bay.

The Gomishan Marshes at 37°15'N, 53°55'E extends along the eastern shore of the Caspian Sea from Gomishan north and northwest to the Turkmenistan border. There are about 4850 ha of brackish lagoons and marshes, their brackish nature occasioned by the rise in Caspian Sea level. There is agriculture, livestock grazing and waterfowl hunting. The fish fauna is mostly unknown but the area is probably and important breeding ground for the commercially important mullet Liza aurata (www.ramsar.org/ram_rpt_37e.htm, downloaded 4 May 2001), for Rutilus rutilus and for Sander lucioperca, and the latter two are open to hydrocarbon pollution (Ghasempouri and Esmaili Sari, 2002).

The Astara lagoon at the western end of the Caspian coast of Iran is separated from the Caspian Sea by a sand bar, and is flooded across this bar during winter storms. The lagoon encompasses about 950 ha and is fed by a river during August to March, reducing its salinity to about 7 p.p.m. There is a rich growth of aquatic plants and the area has potential for fishing and aquaculture (Petr, 1987). Lavandavil Marsh at 38°20'N, 48°50'E is found about 10 km south of Astara and lies within a Protected Area of 949 ha. It is a small swampy woodland and freshwater marsh with extensive stands of Juncus. Abbasabad Dam at 38°23'N, 48°50'E south of Astara is a 45 ha water storage reservoir. Nur or Neur Gol at 38°00'N, 48°33'E in the northwest Alborz Mountains is a 200 ha freshwater lake at 2300 m about 50 km south of Astara. It lies within the Lisar Protected Area which includes the whole watershed of the Lisar River. The lake drains north to an Aras River tributary but freezes over for about 6 months each year. The submergent vegetation is rich. Rainbow trout (Oncorhynchus mykiss - see account of this species) were introduced to the lake in the early 1970s in an attempt to start a sport fishery. There is also a number of permanent and seasonal lakes along the Sabalan Mountain range which lies partly in this basin and partly in the Lake Orumiyeh basin and these are known to have fishes (www.netiran.com, downloaded 17 June 2004).

The "Lapu" Lake, about 20 km northeast of Sari in Mazandaran, is an example of a smaller water body along the Caspian shore, covering about 100 ha with a maximum depth of about 2.5 m, perhaps 3.5 m in winter (Petr, 1987). There is a rich assortment of aquatic plants. In 1985, 90,000 fingerlings of common carp or kopur (Cyprinus carpio), grass carp (Ctenopharyngodon idella) and silver carp (Hypophthalmichthys molitrix) were stocked and 120,000 fingerlings were added in 1986. A good harvest was reported in 1986. There is a wide variety of reservoirs on the Caspian shore, varying in size from about 10 to 400 ha. Some completely dry out in summer when water demands are high but others are stocked with common carp, silver carp and, to a lesser degree, grass carp. There are also populations of native fishes such as kopur Cyprinus carpio and ordak mahi (Esox lucius) but not in commercial quantities.

The "Amirkelayeh" Lake or Lagoon is located between the cities of Lahijan, Langarud and Kiashahr at 37°17'N, 50°12'E. It is an example of a larger, freshwater lagoon as it encompasses 1230 ha, being 4.5 km long and up to 1.7 km wide. The lake is in the Amirkelayeh Wildlife Refuge and is a Ramsar Site (World Conservation Monitoring Centre, 1990). Average depth is only 1.6 m although some areas reach 4 m (Scott (1995) states 3-4 m on average but up to 6 m). The lake is fed by springs and precipitation and is eutrophic. It lies above the 1980s rise in water level of the Caspian Sea (Khan et al., 1992). It may flood into marshes or the Caspian Sea via a small stream into a channel of the Safid River but is above the recent (1990s) rise in Caspian Sea level. Vegetation is Phragmites communis and Typha with abundant submerged and floating plants such as Nelumbium, Lemna, Potamogeton, Hydrilla, Myriophyllum and Ceratophyllum. The fishes comprise Esox lucius, Sander lucioperca, Carassius sp. (listed as Crucian carp, probably C. auratus), Blicca bjoerkna, Syngnathus abaster, Pungitius platygaster, Silurus glanis, Rutilus rutilus, Cyprinus carpio, and Tinca tinca. Ctenopharyngodon idella has been introduced (Nejatsanatee, 1994).

The Fereidookenar or Fereydun Kenar Marshes at 36°35'N, 52°31'E lie 13 km southwest of Babolsar and occupy 1000 ha. These marshes are artificial, being a damgah or shallow impoundment for duck hunting and water storage. They are one of the best protected wetlands along the Caspian shore as the local duck hunters aggressively restrict access (Khan et al., 1992). There are fringing reed beds of Phragmites australis and Typha with abundant floating and submerged vegetation.

"Seyed Mohalli, Zarin Kola (both at 36°44'N, 53°00'E) and Larim Sara (36°45'N, 53°03'E)" are ab-bandans and associated marshy areas found north of Sari and east of the Tajan River mouth. The first two occupy 600 ha and the last one 1000 ha. Aquatic vegetation is rich, both submerged and floating, and there are extensive stands of Typha and Phragmites. Construction of a large dam on the Tajan will result in an associated network of irrigation canals which may cause ab-bandans to be neglected. The ab-bandans, although artificial, have more of the character of a natural marsh than irrigation channels. Much of this area of the coastal plain has been converted to agriculture which destroys natural wetlands so ab-bandans take on a disproportionate importance as a refuge for wildlife including fishes.

Various dams have been built or are under construction in this basin including the Gourchye Embankment Dam 15 km southeast of Ardebil with a capacity of 20 million cu m, the Yamchi Dam 20 km southwest of Ardebil and the Gaybeglou Dam 40 km south of Meshgin Shahr in East Azarbayjan Province, the Maku Dam with a 150 million cu m capacity in West Azarbayjan and the Agh Chay or Ziaeddin Dam near Khvoy (http://netiran.com/news/IRNA/html/950914IRGG06.html; http://netiran.com/news/IRNA/html/950914IRGG10.html; http://netiran.com/news/IranNews/html/96102201INEC.html). The Neka Power Plant in the eastern Caspian basin entrains a large amount of debris and algae that prevent effective physical systems of fish protection from entrainment. An electrical fish protection system is used instead. Inflatable rubber dams are now being constructed in the lower reaches of rivers, e.g. the Babol, to block the rise in Caspian Sea level such that agricultural water intakes will not be contaminated with saline water. The effects of these dams on fish migrations and biology is unknown (www.satujo.com/english/barrage/dams4.htm, downloaded 20 December 2002).

Qanats and springs are not a feature of this basin as in so many other parts of Iran, except for the drier areas drained by the Qezel Owzan and other streams of the plateau and in the drier valleys of the east away from the rainfall of the Alborz-backed Caspian lowlands. One particular artificial habitat for fishes in the lowlands are the ab-bandans, shallow freshwater marshes maintained as habitat and overwintering areas for waterfowl and for conserving water for rice fields (Beaumont and Neville, 1968). Some ab-bandans around the Anzali Mordab were set aside as refuges for waterfowl and incidentally would protect some fish species threatened by the draining of marshes. Construction of irrigation dams will also lead to abandonment of ab-bandans. Ab-bandans and damgah (ponds made specifically for duck trapping) have declined in number but still encompass 10,000 ha (Scott, 1995).

Extensive stocking of commercially important species in the sturgeon (Acipenseridae) and carp (Cyprindiae) families takes place annually in the Caspian waters of Iran. These are detailed under the species accounts. Varedi and Fazli (2005) examined the rivers Shirud, Tonekabon, Larim, Tajan and Goharbara of Mazandaran for the physico-chemical properties of estuarine water in 2000-2001. Only the Shirud and Tonekabon met U.S. Environmental Protection Agency standards for release of fingerlings, the other rivers failing because of water abstraction and improper land use development.

Introduced species based on a summary by Mamaev (2002) include Liza aurata and L. saliens (Mugilidae), Platichthys flesus (Pleuronectidae, apparently not surviving), Psetta maxima maeotica (Scophthalmidae, as Rhombus maeoticus in TACIS (2002) and probably not surviving), Scomber scombrus (Scombridae, not often recorded elsewhere in the literature (an example is TACIS (2002), probably not surviving), Engraulis encrasicholus (Engraulidae, probably not surviving), Anguilla anguilla (Anguillidae), Gambusia affinis (Poeciliidae), Oncorhynchus keta , O. kisutch, O. gorbuscha and Salmo salar (Salmonidae), and Ctenopharyngodon idella, Hypophthalmichthys molitrix, H. nobilis (Cyprinidae). The Indian carps Cirrhinus mrigala, Labeo rohita and Catla catla are being reared in aquaculture stations and are potential escapees into the natural environment (Gilkolaei, 2007).

Zoogeographically, Berg (1940) considers this part of Iran to belong to the Kura-Iranian sector of the Caspian District of the Ponto-Caspian-Aral Province. This fauna is very similar to that of the Kura River although certain genera are absent, even in the Safid - a major river, such as Chondrostoma, Gobio and Leucalburnus.

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© Brian W. Coad (www.briancoad.com)