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APPENDICES

Appendix 1
ANZALI LAGOON AND ITS WATERSHED

The Talesh Mountains form the western portion of the Elborz. They rise steeply from the Caspian Sea coastal plain and form the upper regions of the Anzali Lagoon watershed. They are moderately folded sediments of the Cretaceous and Jurassic periods. Water has cut the deep valleys of the eleven most important rivers feeding the Lagoon. The resulting sediment deposits form the narrow coastal plain which has been further enlarged by the shrinkage of the Caspian Sea (Kimball and Kimball, 1974). The broad-leaved deciduous forests on the Talesh slopes are a relict of the warm temperate forests that covered a large part of Europe and North Asia in the late Tertiary and which were decimated during the Pleistocene glaciation. Severe cutting and grazing pressure during the last 50 years has degraded much of the forest. Its present area is 161 920 ha, 43.2 percent of the 374 000 ha of total watershed. The marsh- and forest- covered coastal lowland, once the favourite habitat of the Caspian tiger, has been replaced by agriculture, mainly ricefields. The watershed receives 1 500–2 000 mm of precipitation annually; in the mountains heavy precipitation without a dry season occurs, while in the foothills and lowland, autumn is the wettest period. The density of the natural river network on this humid watershed is rather high, around 1.7 km\km-2. In addition, there is an extensive tunnel and canal system for ricefield irrigation; this diverts water from the Sefid River into the Anzali watershed. The Manjil Dam was built on the upper course of the Sefid River in 1961; the Sangar Dam was completed in 1965 and the Tarik Dam three years later. The channelized water is diverted into the eastern and central parts of the Anzali watershed. The present land use pattern in the watershed is stable and well-balanced (Table 1), 94.8 percent of the total watershed being covered with forest, waterbodies and agriculture.

Anzali Lagoon is located west of the Sefid River delta and embraces Bandar Anzali, the biggest Iranian port on the Caspian Sea, in the southwestern region of the Caspian coast, at 37°28'N, 49°25'W (Fig.1). The lagoon forms a wetland complex consisting of the open waters of the Abkanar Region or western basin, the Phragmites-, Typha- and Scirpus- dominated Shiakishim region (southern basin) and the Seyjan region (eastern basin) which has more submerged and floating vegetation. There is a significant standing stock of the Caspian lotus Nelumbium caspium scattered all over the Lagoon. The feeder rivers of these lagoons have been deepened by erosion caused by the lowering of the Caspian Sea from 1929 to 1977. They flow through Shiakishim and Seyjan and drain the watershed runoff directly into the single outlet of the harbour (the five outlets that drain the lagoon are locally known as rogas). During the past three to four decades the lagoon was a freshwater ecosystem due to the significant Caspian Sea level decline and the considerable river discharge collected in the humid watershed. Rising sea level since 1977 increased the salinity in the isolated Abkanar Region which receives only 65×106m3 of freshwater from one small river and the deepened rogas. The highest salinity (3.49 g/l) was measured in the Anzali roga.

Annual precipitation, based on the average for the period 1964–84, is 1 279 mm (Table 2). The annual evaporation rate is 976 mm. However, the runoff, as calculated from measured discharge values, is greater than the difference between precipitation and evaporation. This could be explained by some water being diverted from the Sefid River for irrigation purposes.

The Lagoon has long-served as an important spawning and nursery ground for economically important anadromous fishes. The lagoon also represents an internationally important wildlife reserve and sanctuary with recreational potential that includes angling and hunting.

Appendix 2
SEDIMENT LOAD AND SILTATION

A Soviet report (Hydrorybproject, 1965) mentions a high silt load reaching the lagoon annually to be at around 5.6106 t. This calculation was based on the total suspended solids (TSS) content of the Caucasian rivers as well as on a short-term observation of the very turbid Sefid River of a nearby forestless watershed which, however, does not discharge to the Lagoon. The first measurement of the TSS concentration in the rivers flowing into Anzali Lagoon was conducted only in 1967–68 (Kimball and Kimball, 1974). The Kimballs measured and presented only the annual average values for Pirbazar, Pasikhan and Shakraz Rivers as 208, 299 and 244 mg dm-3. These values are rather low and indicate the healthy condition of the vegetated Anzali watershed despite the fact that two irrigation canals were put into operation in 1965 and 1968, diverting part of the turbid Sefid river with an average annual TSS content of 4 541 mg.dm-3 into the ricefields on the Anzali watershed. However, most of the suspended particles have been sedimented on ricefields and the TSS content of Pirbazar, Pasikhan and Shakraz rivers remained low, as Kimball's own results clearly demonstrated. Surprisingly, they emphasized the high siltation rate and rapid delta formation, and explained this by the sediment load transported by the diverted Sefid River. The TSS concentration was measured once more during 1983–84 in the Pirbazar River. The annual average was again as low as 284 mg dm-3. So there is a conflict between the visible high siltation rate accounted for the rapid delta formation and the measured low values of the TSS load.

According to the authors' regular bi-weekly survey of the TSS concentration in the most significant eleven rivers discharging into the Lagoon in 1990–91, the monthly average values of the rivers entering clearly demonstrate that the suspended sediment load is low and cannot be accountable for the visible siltation and delta formation (Table 3). The highest values were detected during water discharge peaks in spring and autumn. During winter the TSS values were extremely and unexpectedly low, which may necessitate a long-term survey on the TSS concentration. Nevertheless, that year-long survey leads to the conclusion that the rivers draining the green Anzali watershed and entering the Lagoon have moderate to low suspended silt concentration, and the rapid siltation and delta formation rate cannot be explained by this load even after the turbid Sefid River water was introduced into the watershed for ricefield irrigation. However, the influence of the diverted Sefid water is clearly visible in the somewhat elevated TSS content in the eastern and central rivers such as Pirbazar, Pasikhan and Shakraz, draining most of the ricefields. The authors calculated the annual suspended sediment loads discharging into the Lagoon for each of the eleven rivers (Table 4). Pasikhan, Pirbazar and Shakraz Rivers are by far the most important silt loading sources, discharging 68.7 percent of the total river load. However, the total suspended load of 386 602 t is much less than the available local rough estimates for the annual load which ranges from 838 175 to 2.5 million t, apart from the first Russian estimate of 5.6 million t. Only the suspended sediment load was measured. The total river load consists of suspended and bed load. The latter however, was not measured in either of the above-mentioned load estimates. Generally, the bed load in lowland rivers is smaller than the suspended load, especially in such alluvia where the fine silt particles predominate. Nevertheless, the bed load under certain condition may make a significant contribution to the total load. This may explain why one would expect a high siltation rate. Those who estimated the sediment load did not take into consideration the significant erosion power of the inflowing rivers. The Caspian Sea level decreased more than 3 m which has contributed to the erosion of river channels and resulted in an increase in bed load.

Local records of the previous 8–11 m deep lagoon water column (Vladykov, 1964; Kimball and Kimball, 1974) showed a drop to 2 m due to the decrease in sea water level. Another 1 m water depth decrease in the Lagoon may be accountable to siltation and to macrophyte invasion which produced an accumulation of organic debris. The suspended load was not enough to cover this siltation rate, especially considering the long term annual average value of the TSS concentration of 169 mg dm-3 in the rogas and in the harbour which discharges into the Caspian Sea. According to Kimball and Kimball (1974), half of this TSS is organic. The remaining half, multiplied by the total river discharge and minus evaporation over the lagoon, gives a total suspended sediment discharge into the sea of some 358 000 t which is very near to the suspended load brought in by the rivers. This means that the bed load with the lowering erosional base might make a significant contribution to the estimated 1 m siltation in the Lagoon. The former peripheral alluvial fan region was heavily eroded with increasing bed load when the lowering lagoon water left large littoral areas dry, decreasing the lagoon surface areas by more than half. This also explains the rapid delta formation or, rather, the permanent delta reformation. With the shallowing water depth the spreading river water has lost the silt load while percolating through dense macrophyte cover. By entering small channels and larger rogas the water devoid of sediments started eroding them. Part of the load from eroding rogas has been discharging into the sea.

Today, with rising seawater level, the Lagoon water level is again rising. The maximum depth in the western basin is approaching 2 m. The rising sea level, and hence also the lagoon level offers a real possibility to restore or improve environmental conditions in the Lagoon at least regarding the siltation problem which was a result of the 3 m drop in water level in Anzali Lagoon.

Appendix 3
CHEMICAL ENVIRONMENT

The water chemistry of the Anzali Lagoon was determined by the 3 m drop in level of the Caspian Sea, as well as the result of nutrient impacts through inflowing rivers, especially the Pirbazar River. The dissolved oxygen in the water column was measured biweekly on 29 stations including rivers, rogas, swamps and open waters in 1990–91. The annual average, minimum and maximum values show a well-oxygenated water in the Abkanar Region and in the inflowing rivers (Table 5). However, the wetlands of Sheyjan and Shiakishim are oxygen-deficient except the upper layers which contain oxygen concentrations as high as 23 mg.dm-3 on sunny summer days. Among the rivers, Pirbazar River is defficient of oxygen especially during summer months when river discharge is low. The surveyed oxygen status explains also the redox status measured during August of 1990 at the sediment-water interface of different ecosystems inside the lagoon (Table 6). The upper 2–3 cm of sediment is oxydized in connecting and collecting canals, in the extensive open water areas and also below emergent macrophytes. Under dense submerged and especially floating macrophyte cover the surface sediment layer is reduced. The pH determines the toxicity of ammonia and nitrite nitrogen for fish. A high alkalinity is regularly present both in open-water areas of Abkanar and among the macrophyte communities in Sheyjan and Shiakishim (Table 7). However, higher ammonia values are restricted to rivers and rogas where there are no macrophytes and algae. High pH and high ammonia concentrations which are so toxic for fish were never found together. However, unusually high concentrations of nitrite (still sub-lethal for fish) accumulated during the cooler winter months in the Shiakishim and Abkanar regions of the Lagoon (Table 8). In Pirbazar and Pasikhan Rivers and in rogas which transport most of the river water directly to the sea, the nitrite build-up started earlier in August. These high concentrations of nitrite, never reported in literature, need further study to be explained.

Appendix 4
INDUSTRIAL LOAD

There is little industrial activity in the Lagoon's watershed. Only 10.5% of the total population of the watershed (Table 9) works in industry. No data on the character of discharged industrial effluents are available. Therefore an indirect approach was used to estimate the industrial pollution load entering the lagoon. This was based on the number of factories, investment (Table 10), size of factories (Table 11) and heavy metal concentrations (Table 12). The number of workers employed by industry in the Anzali Lagoon watershed is rather low, as most of the industrial units are small. There are only 15 factories with more than 1 000 employees and the total number of workers in industry is only 28 765. The total number of factories was 119 in 1983, 221 in 1985 and 375 in 1989. The increasing rate of industrialization will necessitate stricter pollution controls. The overwhelming majority of industrial activities are concentrated in the Pirbazar River, with a sizable solid waste disposal area being located on the upper part of the Siah River, which is the largest tributary of the Pirbazar.

The heavy metal concentrations in domestic, agricultural and industrial effluents were found to be relatively low, even in the heavily polluted Pirbazar River (Table 13). Concentrations of Fe, Zn, Pb, Cr, Cu, Ni and Mn measured in the water of Siah river immediately downstream of industrial, slaughter house and domestic sewage discharge sites were also low. The latter survey covered the whole year except the summer, and although values were well below maximum permissible levels, occasional summer heavy metal stress could not be ruled out on the downstream section of the Pirbazar River.

Appendix 5
PESTICIDE LOAD

Of the 124 450 ha of total farmland, 92 550 ha is covered with ricefields. Most of the land is owned and cultivated by small farmers. Pesticide application is increasing and at present results in an average yield of 2–2.5 t ha-1. The application rate is 2.5 kg ha-1 of which 1.6 kg ha-1y-1 herbicide (Table 14). Around 90 percent of the insecticide applied is the moderately poorly water soluble Diazinon, which, however, has a relatively rapid decomposition rate. Half of the applied herbicide is Paraquat and half is Glyphosite. Due to the low solubility and the rapid decomposition rate as well as the water saving irrigation method, this pesticide load has not in the past represented a direct danger to the Lagoon. However, the pesticide residues were never measured, either in the inflowing rivers or in the Lagoon itself. If rice culture were to result in the production of 4–5 t ha-1y-1. the neccesary pesticide application rate would be 8–10 kg ha-1y-1. It would then become advisable to monitor the residue concentrations in the inflowing river water. At present, the establishment of a pesticide laboratory at the SHILAT Fisheries Research Centre (FRC) does not seem necessary as such measurements can be done elsewhere in Iran, e.g., in one of the university laboratories. The SHILAT FRC in Bandar Anzali was instructed to initiate short-term static bio-assay testing of pesticide toxicity in the inflowing rivers.

Appendix 6
GROUNDWATER NITROGEN LOAD

Among the plant nutrients, nitrate nitrogen moves most easily in water because almost all molecules present are in dissolved form. In coastal regions sands usually favour the rapid movement of groundwater and so may transport significant amounts of nitrate nitrogen to coastal lagoons. In developed countries, where fossile energy consumption is high and intensive agricultural practice dominates, the groundwater nitrate nitrogen flux to coastal lagoon ecosystems is the most significant pathway for nitrogen. On Rhode Island groundwater nitrogen loads ranged from 72 to 95 percent of total inorganic nitrogen load in four coastal lagoons with values of 43 to 94 kg ha-1y-1 (Olsen, 1984).

In the watershed of Anzali Lagoon a Quaternary sediment of sandy texture dominates up to 10 m asl. In the Lagoon itself, silt has been sedimented, the dominating fraction of particle size being around 5 μm. Groundwater level in the alluvia is between 1 and 3 m with a clear seasonal cycle of deeper summer and shallower winter water-table. A definite rise of the groundwater-table has been detected during the last 15 years in parallel with the increasing Caspian Sea level. This change is clearly visible in wells located nearby along the southern littoral zone of the Lagoon. The groundwater level increased from 3.0 m in 1977 to 2.4 m in 1987 in well 18 Z1S, from 3.9 m to 0.8 m in well 14 W1S and from 5.2 m to 0.5 m in well 15 W2S. In order to quantify the groundwater nitrogen flux to the lagoon a survey was carried out monthly from June to October, 1991. This assessed the NH4-N and NO3-N content in eleven monitoring wells installed near to the eleven rivers in the hyporheic zone at 100–500 m from the river banks. Low NH4-N concentrations were present in the hyporheic groundwater of the Pasikhan, Ghazrudbar, Palanghvar, Abatar, Morghak, Bahambar and Shafrud Rivers, reflecting a well-oxygenized, rapidly-flowing and flushing environment (Table 15). Along these rivers the groundwater has good communication with the river water. The groundwater along Shakhraz River has an ammonia content 4–50 times higher than the river water itself which flows in the open channel. This indicates less water movement and poor communication with the running river water. The highly polluted Pirbazar River has high levels of organic nitrogen and ammonia both in the open river water and in the groundwater.

Rivers with low NH4-N content (Table 16) have significant amounts of nitrate, as fully oxydized nitrogen. In the hyporheic groundwater nitrifying bacterial biofilm coatings on the sand and pebble particles oxydize the remaining ammonia to nitrate. The groundwater with high ammonia concentration near to Shakhraz River contained the least nitrate of all the surveyed rivers.

The five months' monitoring of eleven well, gives an average inorganic nitrogen value of 1 529 μg dm-3 for the southern groundwater region that infiltrates into the Lagoon ecosystem through the 50 km of littoral zone. Given the average slope gradient of 90 cm km-1 and the sandy sediment texture, an assumption of the velocity of groundwater movement of 10 m.day-1 was used to estimate the groundwater load. The value of 279 t N.y-1 for the whole Lagoon corresponds to a value of 12.8 kg ha-1y-1. This is about 20% of the total river load, but whilst this is a major portion, 62% of the river load leaves the lagoon directly through rogas and to the sea as groundwater penetrating slowly along the long littoral zone, which is then utilized by the extensive emergent shoreline vegetation.

Appendix 7
ATMOSPHERIC NITROGEN LOAD

The relatively high annual precipitation value of 1 279 mm (average for the period 1964–84) may significantly influence the nutrient status of Anzali Lagoon. In order to quantify this possible nitrogen load, NH4-N and NO3-N concentrations were measured in rainwater collected at the SHILAT Meteorological Station in Bandar Anzali (Table 17). From April to September 1991 the NH4-N content ranged between 310 and 900 μg dm-3 except for the extremely high value of 5 550 μg dm-3 on 10 September. The NO3-N content was highest in April (1 120 μg dm-3) and gradually decreased to 273 μg dm-3 in September. The average total inorganic-N content of the rain was 1 230 μg dm-3 except for the unusually high NH4-N content on 10 September. The average NO3-N, NH4-N content and the total inorganic-N content of rainwater collected in the humid Central Congo Basin in the years 1958–59 were 476, 215 and 691 μg dm-3 respectively (Meyer and Pampfer, 1959). The humid Amazon rainforest region was investigated in the years of 1966–68 and the ranges for NH4-N and NO3-N were characterized by even lower values: 20–300 and 5–300 μg dm-3 (Ungemach, 1971). Around the New Delhi region, with significant air pollution and less total rainfall, the average NH4-N contents were 300 and 2 048 μg dm-3 (Kapoor et al., 1972). Similarly, high total inorganic-N values characterize rainwater over almost all of Europe and over a significant part of North America. It may be concluded that the rainwater supplying Anzali Lagoon contains nitrogen at about the middle of the values measured for virgin rainforest and industrialized regions. Calculating with the average inorganic-N and the average precipitation values, the rainwater nitrogen load annualy brings 15.73 kg nitrogen to each hectare of the Lagoon surface. However, besides this rainwater nitrogen input there is another significant atmospheric source of nitrogen, the so-called dry deposition. In Hungary the dry deposition is almost equal to the wet deposition of rain (Oláh et al., 1991). Unfortunately, the magnitude of dry nitrogen deposition is very seldomly estimated in nitrogen budgets. The high ammonia value measured in the rainwater collector on 10 September occurred after a long dry period. This indicates the significance of this factor on the Lagoon. Its contribution may bring the annual value of the total atmospheric deposition to around 20 kg ha-1. What are the primary sources of the atmospheric nitrogen deposition on the watershed of Anzali Lagoon? The nitrogen emission, that is the atmospheric nitrogen pollution which is deposited with wet and dry deposition, is composed of natural and antropogenic sources. The natural emission is the result of denitrification along with the faeces and urine of livestock and human population. Although denitrification was not measured in either of the watershed ecosystems, the Lagoon itself is actually a denitrifying landscape mosaic and can be considered the main source of natural nitrogen emission. The contribution of human population and of livestock densities of 2.5 and 1.5 ha-1 has less significance. Among the anthropogenic sources of nitrogen emission local boat and car traffic as well as the oil, gas and coal burning industries have to be considered. Moreover, the dominating northerly winds may import a significant amount of nitrogen oxides released by the huge oil industry of Baku.

Appendix 8
RIVER LOAD OF ORGANIC CARBON

The quantity of organic carbon which is drained from the watershed by the river depends upon terrestrial primary production and the rate of runoff (Schlesinger and Melack, 1981; Meybeck, 1982). This natural relation may, however, be significantly altered by human activities, especially by concentrated organic carbon releases from the human population, livestock and food processing industries. The fluvial export of organic carbon in such a semi-arid country as Iran is around 0.3 g m-2yr-1 (Meybeck, 1982). The rich river network on the humid Anzali watershed is expected to export a much greater amount of carbon to the coastal lagoon while influencing its productivity and its chemical environment. The organic carbon loading of the lagoon has never been measured or even estimated. The authors therefore carried out a year round biweekly survey of the organic carbon content of the eleven rivers draining the watershed into the Lagoon and of the outlet which discharges the Lagoon's surplus water into the Caspian Sea. These measurements started in May 1990 and finished in April 1991.

All the eleven rivers were sampled simultaneously, 2–3 km upstream of their deltas along the southern road crossings of the rivers. River water was collected in 5 litre plastic containers and chemical analysis was completed on the day of collection. The organic carbon concentration was measured with permanganate oxidation procedure and the amount of oxygen consumed by permanganate was multiplied by 0.38 to express the result in carbon, then by 2 to compensate the partial oxidation of organic carbon. This gave a better estimate of the actual river load. In addition to the river survey, local statistics were collected to quantify possible organic sources and determine their location on the Lagoon watershed.

One important organic source is that of the leaves shed in autumn in the upper watershed area. Forest covers 43.2 percent of the whole watershed. The sparse foliage produces an annual litter fall of not more than 180 g C m-2 or 291 456 t on the whole forested watershed. If this amount were distributed on 1 m2 of the whole watershed, the value of 78 g y-1 would be reached. However, rivers collecting part of this litter then reaching the lowlands flow mostly through barren or agricultural lands without any significant gallery forest. As a result the organic load of the forested watershed is almost completely decomposed before reaching the Lagoon. Only the finely fragmented, skeletal fraction of leaves reaches the lagoon. Most of the agricultural primary production including crop residues is consumed by the human population or livestock, or is exported from the watershed as processed food. The undigested and unassimilated portion of the primary plant production is released in the form of excrement or manure and appears to be the second most important source of organic carbon load. The bulk of water buffalo and cattle stocks live near to the lagoon or along the river valleys and, as a result, a higher percentage of their carbon release drains to rivers by runoff or to the groundwater. The number of registered livestock made it possible to estimate the total carbon release on the whole watershed after applying the following annual rates of manure production in kilogrammes per animal: cattle - 912, buffalo - 859, sheep - 132, goat - 120 kg C y-1. The total annual carbon release by the animal livestock is estimated at 295 981 t (Table 18). This is very similar to the value of litter fall calculated for the forested watershed, and corresponds to an average manuring rate of 79 g C m-2y-1 for the watershed. There is, however, a significant difference with regard to its influence compared to that of the litter fall. This organic carbon source is located near the Lagoon and along the rivers; it represents more significant and easily available digestable carbon load and makes the contribution of the human population to the river carbon load a crucial influence on the river's and, further on, downstream the lagoon's organic budget. The present population of the catchment is about 1 million (Table 19). Almost 500 000 people live in the regional capital of Rasht and about the same number are scattered in five other rural centres, mainly in Bandar Anzali located in the heart of the lagoon. The rural population will continue to increase at about 2.6% y-1, but the urban population will increase at the relatively high rate of 4.6% y-1, due to immigration into the rapidly developing industries. This trend is in accordance with government policy for expanding the resources of, and redistributing wealth to, rural areas according to the Five-Year Economic Social and Cultural Plan 1990, and so will be a permanent feature of the ecology of the watershed area and will determine the environmental restoration strategy for the Anzali Lagoon. The total organic carbon relase of the human population is 55 237 t y-1 for the whole watershed or, an average value of 14.7 g m-2y-1. Half of this load is concentrated on the subcatchment of the Pirbazar River which drains the Rasht area. Industries on the watershed are agriculturally based at present and the effluent pollutants are essentially organic. Most of the fibre, wood and food processing industries are also concentrated on the subcatchment of Pirbazar River. Their sewage effluent records are either not available or exact data do not exist and so the rough estimate of the local unit of the Environmental Protection Organization has had to be relied upon. They calculate around 35 000 t of organic C y-1 or 9.3 g C m-2. This then represents the third important source of organic carbon load on the watershed. The sum of litter fall, human or livestock release and the effluents of food processing industries is 181 g C m2yr-1. This is the annual organic carbon load of the watershed, but with a pronounced concentration on the subcatchment of the Pirbazar River. Most of this organic material undergoes a rapid decomposition in aerobic terrestrial ecosystems but the focus of interest was on that portion of the material collected by the dense river network then discharged into the lagoon.

In order to quantify the annual fluvial export from the watershed to the lagoon the monthly average concentrations of the organic C were computed for the available integrated discharge of all of the eleven rivers (Table 20). The average values did not show the carbon concentrations of the individual rivers. However, the differences were not significant except at Pirbazar River where, in comparison to the watershed average, the organic carbon content was double during high discharge and triple during the summer low discharge. The overall seasonal pattern of all the eleven rivers was characterized by much higher carbon concentrations during low summer discharge. The organic carbon content at the outlet had less seasonal fluctuation and its absolute values were higher, especially during increasing water discharges. This clearly demonstrated that floods increase the Lagoon's carbon output. Rivers flush out a significant amount of autochtonously produced organic carbon from the lagoon including the coarse detritus of macrophyte origin that originates in the extensive wetlands of the Sheyjan and Shiakishim regions. Contrary to the flood situation during low river discharge in June, July and August, the river carbon concentration and hence the river carbon load was much higher than the concentration at the outlet and than the amount of organic carbon released to the sea. This may also contribute to the severe oxygen deficit that develops among macrophyte communities during these summer months.

Multiplying the monthly average concentrations of organic carbon by the total monthly water discharges gave the total annual load of organic material transported by rivers into the lagoon. During the one year investigation period input was 26 054 t. When divided by the surface area of the total watershed an annual fluvial export of 6.96 g m-2 is obtained that is only 3.84% of the total organic carbon load produced on the watershed and discharged into the lagoon. The bulk (174 g m-2) is either decomposed or processed on the land. A small part also is mineralized in the river network itself before reaching the Lagoon. However, the magnitude of decomposition was measured and estimated only in the Pirbazar River. The fluvial export rate on this humid and steep watershed is in fair agreement with the model developed for transport of organic carbon in the world's rivers (Schlesinger and Melack, 1981).

With the values for organic carbon measured in the outflowing water it was possible to estimate the amount of organic carbon released to the sea. The exact volume of water flowing annually throught the outlet is not known. The river discharge minus evaporation gives an approximate estimate assuming that the groundwater discharge to the Lagoon and the water loss through evapotranspiration is equal. The annual groundwater discharge was calculated at around 182 million m-3. With this uncertainity regarding the magnitude of evapotranspiration, the amount of organic carbon leaving the Lagoon was quantified annually at around 30 494 t (Table 20). This meant that the Lagoon released more than it received; a difference of 4 440 t. The total primary production of organic carbon inside the Lagoon measured by the diurnal oxygen method was also estimated and verified by Landsat imagery as 202 800 t y-1. According to the measurements of community respiration most of this autochtonously produced organic material is consumed in the Lagoon or sedimented and so it is understandable how only 2.2% reaches the sea.

Annex 9
NITROGEN FIXATION BY ANABAENA AND AZOLLA BLOOMS

Anabaena and Azolla are two aquatic plants which trap atmospheric nitrogen. The heavy summer-late summer Anabaena bloom that developed on the open-water areas of the Abkanar basin of the Lagoon fixed an estimated 45 kg N ha-1y-1 of atmospheric nitrogen. With 60.3 km2 of Anabaena bloom water surface, annual nitrogen load of 271 t was calculated for the Lagoon. The aquatic fern Azolla filiculoides was accidentally introduced into the lagoon in 1990 and has rapidly spread over the whole lagoon with the exception of the Abkanar region where the extensive open water and significant wind action has prevented its growth. The 1991 Azolla invasion covered almost all the sheltered open-water as well as the thin Phragmites stands in the Sheyjan and Shiakishim basins. Sufficient knowledge is available on the production, dry matter and carbon and nitrogen content as well as on nitrogen fixation of Azolla (Van Hove, 1989). The following values were used to estimate the increase in nitrogen load that the nitrogen-fixing Azolla invasion brought to the Lagoon. Average Azolla production is: 100 g m-2d-1 biomass, dry weight 7%, carbon content 43% of the dry weight, nitrogen content 3.5% of the dry weight (65% of this nitrogen content was assimilated from NH4-N or NO3-N from the water and the remaining 35% by nitrogen fixation). This latter amount of nitrogen constitutes the Azolla load to the Lagoon. Calculating with these values and a 300-day growing season, this load is significant: 110 kg N ha-1y-1. Part of it, however, leaves the Lagoon especially with floods. The small flowing collecting and connecting canals among the macrophyte communities remove part of the Azolla carpet and the rogas transfer the plants to the sea outlet. The bulk of the Azolla production, however, remains trapped among emergent Phragmites and Typha stands as well as in sheltered open waters. Its decomposition contributes nitrogen to the Lagoon.

Appendix 10
A BRIEF HISTORY OF ICHTHYOLOGICAL INVESTIGATIONS IN ANZALI LAGOON

From 1872 until 1952 the fisheries along the Iranian coast of the Caspian Sea were almost continuously organized and exploited by Russians, who also founded the present research facilities in Bandar Anzali at the end of the 19th century. Bandar Anzali became one of the most important fishery bases along the southern coast of the Caspian Sea. The first information on fish of the Lagoon was published by Russian travellers Gmelin (1785) and Mel'gunov (1863) who mentioned 12 species of fish, including Caspiomyzon wagneri, Abramis brama orientalis, Aspius aspius taeniatus, Cyprinus carpio, Leuciscus cephalus orientalis, Rutilus frisii kutum, Scardinius erythrophthalmus, Silurus glanis, Salmo trutta caspius, Syngnathus nigrolineatus caspius and Stizostedion lucioperca+). The most comprehensive list of fish inhabiting the Anzali Lagoon and some of its tributaries is that by Derzhavin (1934), and later on by Kozhin (1957) and Vladykov (1964). In addition to species listed by Derzhavin, Kozhin introduced Barbus capito (under its Azerbaidjan vernacular name usach-chanary), Gambusia holbrooki, Platichthys flesus luscus and Liza auratus, the last three species the result of introduction into the Caspian Sea watershed. Kozhin indirectly mentioned also Acipenser stellatus (p. 13: “… sevryuga tagged in the Pahlavi Bay has been taken in the Kurinskaya kosa region…”). However, this statement seems dubious, as according to Iranian fishermen neither sevryuga nor other species of sturgeons were ever caught in the Anzali Lagoon. On the other hand, Aspius aspius taeniatus and Barbus brachycephalus caspius need to be included, as they are listed by Hydrorybproject (1962) and RaLonde and Walczak (1970, 1971). At present, 26 species of fish are known for the Lagoon and its watershed (Table 21).

Catch statistics from Anzali Lagoon (Table 24) show the importance of this waterbody for fishing. Vladykov (1964) provided catch records for both the Lagoon and the sea (Table 25). Both sets of statistics show the rapid decline of fish catch since about 1941. It is believed that this was caused by the concurrent decline of the Caspian Sea level (Fig. 10).

+ The full scientific name, valid until now, is introduced only when first mentioned in this text, and in some tables. With exception of Salmo trutta caspius and Rutilus frisii kutum the subspecific status is omitted further.

Appendix 11
VANISHING FISH SPECIES

Five fish species listed by previous investigators from Anzali Lagoon were not found during the IRA/88/001 project. These are: Salmo trutta caspius, Aspius aspius taeniatus, Abramis sapa bergi, Pungitius platygaster and Sabanejewia caspia.

Salmo trutta caspius (Kessler, 1877) - Caspian salmon: According to statistics by Vladykov (1964) the catch of this valuable fish in the Anzali region in 1937–42 varied from 1 319 to 3 037 kg. By 1962 only 18 kg were captured. Then the catch increased to 400 kg in 1967 (Walczak 1972). Since then there are no data on its catch in Iran; however, specimens 1–4 kg in weight were occasionally seen on markets in Astara (December 1989) and also in Bandar Anzali (December 1991). The latter were caught in the sea by sturgeon gillnets. According to local fishermen, Caspian salmon up to 7 kg in weight still entered the Lagoon in the 1950s and continue to migrate upstream to spawning sites in the Pasikhan and Siahdarvishan Rivers. The ripe salmon appeared first in late-September and were caught until end-December. The second migration, much smaller in number, appeared in April–May. The same period of migration in the Sefid River is given by Derzhavin (1934). Although the fishery for the Caspian salmon has been prohibited since 1956, and it is artificially reproduced and stocked since 1972, their number does not appear to have increased. Reasons for the decline, already commented by Vladykov and Walczak, are environmental degradation and alteration, including siltation, damming of streams, extraction of water for irrigation, and unscreened irrigation canals, and extensive poaching, even of the freshly released juveniles produced in hatcheries. Lowering of the Caspian Sea level probably also contributed to its decline, making spawning migrations difficult. Consequently the Caspian salmon stock is heavily reduced not only in Iran but everywhere in the Caspian Sea (Abdurakhmanov 1962).

Barbus brachycephalus caspius (Berg, 1914). Derzhavin (1934) writes that this species of barbel is found in small numbers along the Iranian coast. Vladykov (1964) did not mention it in the catch statistics. However, the Hydrorybproject (1965) included the Caspian barbel by name in the category of “other species” together with Aspius aspius, Vimba vimba and Chalcalburnus chalcoides. This category is mentioned only in the period 1935–51 when its catch in the region of the Anzali (Pahlavi) Bay varied from 7.2 to 72 t. According to RaLonde and Walczak (1970, 1971) the total catch of the Caspian barbel in Iranian waters in 1969–70 and 1970–71 was 54.6 and 32.9 t respectively. Most productive in this respect was the Anzali region where in the respective years 28.7 and 14.4 t of barbels were taken by fishermen on their route to inflowing streams. RaLonde and Walczak (1970, 1971) made a stock assessment of the Caspian barbel for the Anzali region: 3–7 + year old barbels were caught, dominated by 3–5 year old fish, ranging from 380 to 710 mm of FI in size. They mentioned (1970, p.30; 1970, p.30) the “…extremely fast growth” of this species which attained as much as 2 kg during its fifth year of life. At present, however, B.brachycephalus should be considered a vanished species in the Lagoon and its watershed. All barbels found in the fishermens' catches during the project investigations were Barbus capito, not B.brachycephalus. On the Bandar Anzali fish market the latter species is seen very seldom, supposedly being caught in Anzali Lagoon, but the authors cannot confirm this. Electrofishing in tributaries also failed to capture B. brachycephalus. The reasons for the decline of this species are the same as those for Caspian salmon, i.e., alterations of the environment, and the extremely low reproductive rate. B.brachycephalus lays semipelagic eggs which are shed over the pebbly or sandy bottom in the main channel of streams (Abdurakhmanov (1962).

Aspius aspius taeniatus (Eichwald, 1831). Derzhavin (1934), Kozhin (1957) and Vladykov (1964) did not list the asp among the commercially important fish species. RaLonde and Walczak (1970, 1971) mention that the catch of asp in the Bandar Anzali region in 1969–70 and 1970–71 was 45.2 and 36.1 t, which is 84 and 69% of its total Iranian catch respectively. Three to six-year old fish of 330–630 mm TL and 3–6 year old were taken, the growth of which was assessed as very rapid (1 kg in weight during the fourth year). Both authors (1970, p.37) mention that “Again a large amount of immature fish are caught, in this case 48%. There is a drastic drop in the number of fish caught after the first spawning occurs, 5 and 6-year old fish make up less then 20% of the catch”. Local fishermen said that asp started to appear in their catch mostly in March– May. Its spawning grounds there were not properly known. According to Shikhshabekov (1979) the spawning grounds of the subspecies taeniatus in Dagestan “…usually occur in open parts of lakes and stream channels with running water, rarely in places weakly overgrown by the reed Phragmites and Typha.” The present survey of fishermens' catches from the Anzali Lagoon did not show any, and the few specimens seen in the market in Bandar Anzali were captured in the sea. The decline of this species seems to result from indiscriminate catching of sexually immature fish (RaLonde and Walczak, 1970). However, environmental changes also significantly contributed to the extinction of this species from the Anzali Lagoon.

From the commercially non-important species Abramis sapa bergi, Pungitius platygaster and Sabanejewia caspia were not recorded during the present survey. The first species was always very rare in this region+). Derzhavin (1934) found it in the stomach content of Silurus glanis from Anzali Lagoon. Its current absence in this waterbody could be the result of the loss of its spawning grounds which are located in streams with gravelly bottoms (Abdurakhmanov 1962). The nine-spined stickleback has probably been rather abundant at the beginning of this century, as Derzhavin (1934) sampled “Dozens of typical specimens in the Khalkai (Anzali Bay)…”. The present absence of this species in the Anzali Lagoon could be the result of the change of the brackishwater character of the Lagoon into freshwater, the siltation, oxygen depletion and the loss of spawning grounds. The reasons for the absence of Sabanejewia caspia are not clear. Derzhavin (1934) found more S. Caspias than S. aurata. The former was collected in the Khalkai river (Anzali Bay), the second has not. The biology of both species is poorly known. In Azerbaijan S. aurata seems to be more widespread than S. caspia. While the latter is limited to the lower course of the Kura River where it inhabits some waterbodies, the former is present throughout the Kura and Aras rivers and most of their tributaries (Abdurakhmanov, 1962).

Platichthys flesus luscus (Pallas, 1811) is a fish exotic to the Caspian Sea. The fish was introduced there probably for the first time in 1902 (Kozhin, 1957). Fish released at the Dagestan coast migrated also southward and some entered Anzali Lagoon where they were recorded in 1931–34 and later (Shukolyukov, 1937). Although Kozhin (1957) suggested that the plaice reproduces in the Caspian Sea, Karpevich (1975) doubted that and Kazancheev (1981) did not include it in the list of Caspian Sea fish.

Caspiomyzon wagneri (Kessler, 1870). The Caspian lamprey never belonged among the commercially important animals in Iran for religious reasons, (but in the former USSR it is considered to be a valuable and delicious fish (Abdurakhmanov 1962, Holčík 1966). Two specimens, both females 320 and 370 mm in TL were caught during the spawning migration in February and April 1991, one in the Pirbazar roga and the second in Siahdarvishan River. This species seems to be rare. Derzhavin (1934) recorded the presence of this species in most of larger streams such as Astara and Sefid Rivers. According to fishermen from Bandar Anzali in the 1940s the Caspian lamprey regularly entered Anzali Lagoon in spring and 40–60 specimens were found in one haul of the small mesh beach seine while fishing for Chalcalburnus chalcoides. Weirs and dams built on most of the incoming rivers prevent the upstream spawning migration of this species. This results in a very limited opportunity for the fish to spawn, leading to its, decline. Its presence in Anzali Lagoon, and in the Sefid River from which one male was taken in September 1991, suggests that that water quality in these water bodies is reasonably good since ammocoetes of lampreys in general are known to disappear from polluted streams (Sterba, 1962; Hardisty, 1986).

+ According to Abdurakhmanov (1962) this species is distributed mostly in the Kyzylagach Bay and along the Lenkoran coast, and almost all catch amounting to 5–17 t in 1950–58 was taken in the Kura River

Appendix 12
FISH SPECIES NOT RECORDED BEFORE

Eleven species of fish had not been recorded by the previous investigators in Anzali Lagoon, or some had been misidentified. Most are exotic species, and were accidentally or intentionally introduced into Iran. A brief account of their biology and ecology follows, as based on the present study.

Clupeonella cultriventris caspia Svetovidov, 1941: This euryhaline species was sampled in the confluence of the Pasikhan and Pirbazar Rivers in May 1991. This is a new record for the freshwaters of Iran, although in streams entering the northern Caspian, such as the Volga and Ural, and also in the Terek River it is common (Chugunova, 1949; Svetovidov, 1952). As all specimens caught were mature and ripe it is possible that the fish spawns in the Pasikhan and other rivers entering the Anzali Lagoon.

Alosa caspia persica Il'in, 1927: All previous records report the presence of A.c.knipowitschi Il'in, 1927 in Anzali Lagoon which is a typical environment for this species. Our samples showed the number of gill rakers in 29 specimens ranging from 97.7 to 162.6 mm in TL (range from (39) 55–101 (× = 78.6). Thus, our fish is A. c. persica, as the number of gill rakers coincides with that given by Berg (1948) and Svetovidov (1952) for this subspecies.

This migratory fish appears in the catch from the Lagoon between the end of April until the beginning of June. Of 29 specimens studied, all but two were sexually mature and ripe fish and two of them, taken on 22 May 1991, were spent, suggesting that the fish spawns in the Lagoon. Males predominated over females by a factor of 1.7. The females are bigger than the males, the average total length being 146.1 mm (ranges 109.6–190.1) and 139.5 mm (121.4–151.2) respectively. Total length may be converted into fork length by the formula FL = 6.054 + 0.833 TL. The proportion of this shad in the catch from the Lagoon in 1990–91 was very low, amounting to only 5 kg (= below 0.1% of the total fish catch), but this certainly does not correspond with its actual, although seasonal, density in the Lagoon. Due to its high fat content, this fish, together with the other species of the genus Alosa in Iran, is considered to be of inferior quality. It is only rarely used for food and, when caught, is usually discarded.

It is not clear why A.c. knipowitschi, recorded by previous researchers, has been replaced by A.c. persica. At the beginning of this century it was the only shad in the Lagoon constituting a substantial part of the Silurus glanis diet (Derzhavin, 1934). Berg (1948–49) quoted Shikolyukov that in 1933–34 about 420 t of this shad was caught in the Lagoon. This could be a mistake, as in the statistics published by Vladykov (1964) the same amount (420.6 t) of “Caspialosa spp.” was caught in that year, i.e., various species of shad. In these statistics Caspialosa caspia is listed separately and not distinguished by subspecies. Their catch records started only in 1941 but already cease in 1951. From data introduced, it may be concluded that migration to Anzali Lagoon has not been very regular, as the catch strongly fluctuated in certain years with ranges from 0.1 to 219 t. It is possible that both forms occurred in the Lagoon as Svetovidov (1957) quoted Meisner that (p.241): “… specimens from Pahlavi Bay having 50–100 gill rakers (yearlings) considered to be A.caspia knipowitschi by Il'in, is necessary to regard as A.caspia persica, because after the first year the number of gillrakers in A.caspia no longer increases.” Svetovidov (1957) writes that the geographical distribution of both forms which occur along the southern coast of the Caspian Sea is narrow but different. A.c. knipowitschi predominantly inhabits the western portion of the region, Anzali Bay, Astara River and the Bakinskii archipelago, while A.c. persica is mainly in the eastern part, Astrabad (Gorgan) Bay and also northwards into the Bay of Krasnovodsk.

The present study suggests that stocks of Alosa caspia will increase in Anzali Lagoon due to increasing salinity and restitution of environmental conditions prevailing there before the lowering of the Caspian Sea. It may be utilized fresh, salted, marinated or canned as are other forms of A.caspia (Svetovidov, 1949).

Anguilla anguilla (Linnaeus, 1758). Fishermen reported the occurrence of single specimens of eel both in the Lagoon and in the rogas. The present study also found the fish near Bandar Anzali.

The main fishing ground for eel is the southern coast of the Caspian Sea between Bandar Anzali and the mouth of the Sefid River, where 10–40 specimens are caught annually weighing up to 3 kg. Some of them may occasionally be seen in tanks of the SHILAT Experimental Hatchery in Bandar Anzali. According to fishermen's observations, catches of eels seem to be increasing, but exact statistics are not known as this species is not used for food. However, their observations are in agreement with the situation on the northern and western coasts of the Caspian Sea (Abdurakhmanov and Kuliev, 1968; Kazancheev, 1981) where the number of eels in the catch of the Soviet fishermen is also increasing. As stated by Kazancheev (1981) this is due to the regular introduction of elvers imported from France and the UK which are stocked in the Volga River. Abdurakhmanov and Kuliev (1968) recorded eels in the Kura River in Azerbaijan up to 50–60 km from its mouth. The authors are convinced that the eel also enters other rivers flowing from the northern slopes of the Talesh Mountains. Although the condition of these eels is better than those in the Baltic Sea drainage the introduction of this species into the Caspian Sea would appear to be of little value. It cannot be expected that the eel would adapt to the conditions of the Caspian Sea as Abdurakhmanov and Kuliev (1968) suggested.

Aristichthys nobilis (Richardson, 1844)
Ctenopharyngodon idella (Valenciennes, 1844)
Hypophthalmichthys molitrix (Valenciennes, 1844)

The three Chinese carps were introduced probably in the mid-1960s. Some of them were imported from Romania, while others from the former USSR. The silver carp is mostly a hybrid between Hypophthalmichthys molitrix and Aristichthys nobilis. All specimens caught and examined displayed the long scaleless keel between the anal opening and throat, characteristic of the silver carp, and also the well separated gillrakers, typical of the bighead carp. The colouration resembles that of the silver carp. According to SHILAT statistics, Anzali Lagoon is regularly stocked with grass carp juveniles and also with silver carp and bighead carp. Chinese carps occur mostly in the western region of the Lagoon but sometimes also in outlets. Both are appreciated as good pan-fishes and are also kept in ponds by the local fish farmers. Chinese carps have established self-reproducing populations in the Volga and Terek Rivers (Kazancheev and Karpevich, 1975; Kazancheev, 1981; Abdusamadov, 1986). The conditions in the Anzali Lagoon and its watershed are probably not suitable for natural reproduction of these fish.

Carassius auratus (Linnaeus, 1758)

This fish, exotic to Iran, is present throughout most of the waterbodies in Gilan and Mazandaran Provinces (Razavi, pers.comm.). It was accidentally introduced with the Chinese carps in about 1964. Since the end of the 1960s Carassius auratus(German carp) has been increasing in number and has become the dominant species in the Lagoon catches. It is interesting to note that the expansion of this species in lran has coincided with the population explosion and expansion of this species in the Danube River system in Europe (Holčík, 1980). The dominance of the German carp is important from two aspects: (i) it indicates the previous deterioration of environmental conditions in Anzali Lagoon, especially the poor oxygen content; (ii) it adds another cyprinid to the two existing native cyprinids (e.g., Cyprinus carpio and Abramis brama). As far as is known, Carassius auratus populations west of the Amur River (eastern Siberia) are predominantly composed of females while west of the Ural mountains almost all populations are monosexual, comprised exclusively of females. They mate with males of other species of cyprinids, and also cobitids. The sperm of these males only activates the development of the German carp eggs, and the offsprings are 100% females of the species C.auratus (gynogenetic type of reproduction). It has been found (e.g., in the Danube River) that, due to the presence of this species, the density and subsequently also the catches of some cyprinids, especially common carp and bream, have significantly decreased. Mathematical modelling confirms that the C.auratus specific style of reproduction has a similar effect as predation (Kme & Holčik, 1992a, b). It seems, however, that gynogenesis takes place only in an ecologically disturbed ecosystem. Abdurakhmanov (1962) did not mention C. auratus in the waterbodies of Azerbaijan, and Kazancheev (1981) stated that it inhabits the Terek River delta and is very rare in the Volga delta. With the increasing salinity of the Lagoon population, density of C. auratus will decline and then be forced out into incoming rivers.

Gambusia holbrooki (Girard, 1859): Earlier reports (Kozhin, 1957; Armantrout, 1969) mentioned only Gambusia affinis for the southern coast of the Caspian Sea or hybrids of the two (Abdurakhmanov, 1962). Numerous samples of this species collected in various parts of the Lagoon revealed only the presence of G.holbrooki, the specific characters of which are in accord with data for this species given by Wooten et al., (1988) and Lydeard et al., (1991): ten rays in A, mostly seven rays in D and the presence of denticulations on the third anal ray of gonopodium. Although the mosquitofish is frequently blamed for eating the eggs and juveniles of fishes (Myers, 1965: Abdurakhmanov, 1962) its predatory role in Anzali Lagoon is certainly negligible as it occurs almost exclusively in the eastern and southern regions of the Lagoon which are almost devoid of other fish species.

Hemiculter leucisculus (Basilewski, 1855). Among fish species occurring in the Anzali Lagoon the common sawbelly deserves special attention. This species, identified from the Lagoon in 1990, is a new record for Iran. Its original distribution includes rivers of China, Koreas and Viet Nam, and the basin of the Amur River. In the 1950s and 1960s the common sawbelly and other coarse fish were accidentally transferred with juveniles of the Chinese carps from China to Central Asia. As the latter were imported into Iran from the former USSR in 1967 it is almost certain that the consignment of Chinese carps contained also the common sawbelly. It can be expected to be widespread in Iran, but is probably considered to be the native Caspian shemaya, Chalcalburnus chalcoides which is very similar. The share of Hemiculter leucisculus both in the total catch and in the fish market in Bandar Anzali continues to rise. Although not a predator, in Iran, it may compete for food with the native fish and might also feed on their eggs and hatchlings, as was reported from the USSR fish farms and open waterbodies. Therefore, its presence in Iran must be considered undesirable and it should be controlled. Ponds and lakes in Iran where Chinese carps have been introduced, should be checked for the presence of this fish. Also, new transfers of Chinese carps and other fish both within and from outside the country should be properly checked for the presence of this and other undersirable fish species, and specimens found removed and destroyed. For further details see Holčík and Razavi (1992).

Liza auratus (Risso, 1810) has been introduced into the Caspian Sea together with two other mugilids in 1930–34 (Berg, 1949; Kozhin, 1957; Karpevich, 1975) and since the 1940s it started to appear in fish catches in almost all of the Caspian Sea (Belyaeva et al., 1989). According to Shukolyukov (1957) this species appeared in the vicinity of the Lagoon (Anzali region) in 1933. Vladykov's (1964) statistics also show the increasing catch of mullets+) in the Anzali region (Table 25). However, there are no reports that this species has been found in the Anzali Lagoon. Present catches in the Lagoon are rather low and in 1990–91 they did not exceed 3 kg, mostly juvenile fish 150–200 mm in SL, occasionally also up to 260 mm in SL. They entered the Lagoon from January until March to feed (Khoroshko, 1980). The authors suggest that with increasing salinity and area of the Lagoon, the abundance of this mullet will also increase.

Atherina mochon pontica Berg, 1916: This is a marine fish, the occurrence of which in Anzali Lagoon may be explained by the intrusion of seawater in recent years. However, it may also have been there in the 1930s and have been overlooked by previous investigators. It is known to dwell also in entirely freshwater and spawning takes place in marine, fresh or brackishwater (Berg, 1949; Abdurakhmanov, 1962; Kazancheev, 1981). It occurs seasonally in Anzali Lagoon. It was found in the Lagoon and in its outlets (Sowsar roga) in Spring (April).

+ The catch statistics in both USSR and Iran do not consider the three species separately; L. auratus forms 80–90% of the total catch on average (Belyaeva et al., 1989)


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