During last decades, as a result of intensification of anthropogenic effects, biological diversity in Caspian Sea and river flowing in it has been notably reduced, what is observed in form of decline of number of species (subspecies and populations) of aquatic organisms, depletion of genetic fund of valuable commercial species of fishes (sturgeons) and cut down of areas for spawning and fattening. The role of biodiversity and maintenance of sustainable fisheries development in Caspian Sea is reduced.
Russia signed International Convention on Preservation of Biological Diversity (Rio de Janeiro, 1992) among first member-states (1992) and in 1995 ratified it. State Scientific-Technical Program on Preservation of Biodiversity was worked out in 1993 and became effective from January 1994, the objective of which was consolidation of efforts of Russian scientists for evaluation and composing of the inventory of biological resources, development of set of measures on conservation, rational utilization and rehabilitation of biodiversity in separate regions.
Within the framework of this Program, Caspian Scientific-Research Fisheries Institute (CSRFI) accomplishes task: “Status and direction of sustainable utilization of fish resources of nether Volga and northern part of Caspian Sea”.
The present status of knowledge about ecosystem and biodiversity of Caspian Sea are reflected in monographs “Caspian Sea: Fauna and biological rpoductivity” (1985), “Caspian Sea: Ichthyofauna and commercial resources”, (1989); thesis of reports of First International Conference “Biological Resources of Caspian Sea”, (1992, the city of Astrakhan); thesis of reports First Congress of Ichthyologists of Russia (1997, Astrakhan); monograph “Scientific basis for sustainable fishery and regional distribution of commercial objects of the Caspian Sea” (1998); in numerous articles published in Russian and foreign magazines and bulletins, among latter it is worth to mention “Sturgeon Biodiversity and Conservation” (1997), and “Studies on the present status of marine biological resources of the Caspian Sea, Bioresources network meeting, Bordeaux, November 1997”.

Published works contain a detailed analysis of all complex of phenomenon and processes determining natural conditions of Caspian Sea and their change trends.

Unique features of flora and fauna of the Caspian Sea closely related with physical and geographical peculiarities of this reservoir – its insularity, level fluctuations, low salinity and ion-salt content of its waters, distinct from ocean’s.
Hydrology- hydrochemical regime, biological productivity and trophic structure of ecosystem of Caspian Sea to a significant extent depend on natural-climatic factors forming at the basin’s water collection liquid and biogenic drainage. Main role of water supply for the Caspian Sea is played by Volga river, the share of which is 80% of total drainage of rivers flowing into the Caspian Sea.

Status of sea level is very essential for formation of sea bioresources, and its amplitude of fluctuations for the current century is 3,13 m., reaching minimal level -28.92 m in 1977 and maximum –25.79 in 1900. Such sea level fluctuation crucially change environmental conditions for biocenosis evolvement in the mouths of the rivers and productivity properties of the sea itself, especially its shallow northern part. The analysis of date for many years (30s-90s), characterizing ecosystems and bioresources of Volga-Caspian basin under changing water regimes of rivers and sea showed that most considerably, the biological activity of the northern part of the Caspian Sea was reduced in 60s, as an outcome of inception of regulation of Volga river and during (30s-70s) periods of keen fall of sea level accompanied by decrease of water volume of Volga. Critical sea level for ecosystems and biodiversity of northern part of Caspian Sea is –28.5m, decline of level till -29.0 is considered as disastrous.

One of the property determining biological productivity of Caspian Sea is salinity. Caspian Sea has average salinity 12.80-12.85 o0/4oo0, and comparing with ocean water is relatively poor with sodium and chlorine and rich with calcium and sulfates what makes it closer to river water with regard to ion correlation. Desalting effect of Volga river affects not only on northern part of Caspian Sea. Transformed Volga waters, having mixed with sea waters, penetrate far to the south till middle and south parts of Caspian Sea.
Because of meridian extension of the sea, its distinct parts are located in different climate zones. Thermal regime of the northern part of Caspian Sea is of continental character: in winter its water area is covered with ice and in summer its water warms until 24-26.5 degree and higher. Thermal regimes middle and southern part of the sea is more stable, even in winter the surface is not covered with ice and the water temperature in February does not decrease below 5 degree.

Peculiarities of hydrological and hydrochemical regimes of the sea, along with fodder productivity determine migration character of migratory and sea fishes and the importance of some districts in terms of fishes and seals fattening and breeding.

Shallow northern part of Caspian Sea with its low salinity waters, well warmed in summer and rich fodder base, is a vast fattening habitat for growing fingerlings and adult fishes – sturgeons, herrings and carps and others. In autumn, as coastal waters get colder, the reverse migration of sturgeons and herrings begins to the wintering places in middle and south parts of Caspian Sea. Fodder and fish productivity of the northern part of the sea to depends to great extent on volume of Volga drainage and sea level. In winter, propagation of seals on the ice of the northern part of Caspian Sea occurs.

Deeper middle part of the sea has free water exchange with northern. Main flow pf Volga water goes along western shore and together with outlet of such rivers like Terek, Sulak, Samur determines high productivity properties of western shelf of the middle part of Caspian Sea.
Stream of fresh, relevantly cool Volga water flowing in spring along the western coast is an attractive factor for sturgeons and black-back herrings, herrings and also sprats migrating for spawning to Volga river for reproduction purposes.
Spring-summer migration of herrings and sprats after spawning in northern part of Caspian Sea is directed to the south, also mainly along western coast of the middle part of Caspian Sea, where, later on, sprats are fattening.
In winter time, western part of Northern Caspian Sea is wintering place for northern caspian population of Russian sturgeon, stellate and great sturgeons and also sprats.
Eastern part of middle Caspian Sea, located in internal-drainage area of Mangishlag semi-island, has more lengthy shelf zone, than western. Their productivity capacity, together with effect of Volga drainage, is determined by the impact of upwelling and in winter - by compensatory streams of warmer waters from Southern Caspian Sea.
Migratory paths of sea herrings, gray mullet going to Northern Caspian Sea for propagation lay through eastern part. In winter, sturgeons, predominantly stellate sturgeon, can be found here.
Eastern part of Middle Caspian Sea plays an important role in reproduction and fattening of anchovy-type sprats. Anchovy-type sprat inhabits enormous area of Middle and Southern Caspian Sea, except gulfs and vast coastal shallow waters. Most of schools of these fishes is concentrated in the circle current zone, in the depth of 50-200 m., but also high concentrations are observed in central, deepest areas of the sea. Migrating along the eastern and western coasts schools get mixed with one another, particularly in the area of Absheron threshold. The southern part of the sea is the deepest part and with most complicated bed relief. Distribution of depths is characterized with narrowing of shelf zone along western (Azerbaijan) and southern (Iran) coasts, near the Turkmen coast, shelf is wide and relatively shallow with depths reaching 100 m. This part of the sea is full with elevations of sea bed (shoals, islands), which are natural original reefs and hearths of intensive biological productivity. Here, due to bed’s irregularity and presence of deep cavities, main wintering place of sprats and herrings are located. Southeastern part of Caspian Sea is the area of permanent inhabitation of sea herrings and sturgeons wintering and fattening places.
Thus, although role of different regions of Caspian Sea for separate commercial objects changes during the year, in long-term prospective, some certain persistency is existent and namely:

1. Northern Caspian Sea in spring-summer period is the major fattening place for fingerlings and adult individuals of sturgeon and half-migratory fishes, and also natural habitat for spawning of sprats and migrating sea herrings. In winter, sea seal propagates here.
2. Middle Caspian Sea, especially its western shelf is the main migratory paths of fishes (sturgeons and herrings) moving to Volga river and Northern Caspian Sea for spawning, and plays leading role as district for wintering of northern caspian sturgeon populations.
3. Middle and Southern Caspian Sea in circle current zone – is the main district of concentrations of anchovy and big-eye sprats.
4. Turkmen shelf is the wintering and fattening place for sturgeons.

As far as assessment of transboundary biodiversity priorities concerned, it is necessary to stress out broad migrations of sturgeons along the coast of entire sea, what stipulates application of unified agreed measures on preservation of stocks of these species of fishes.

Studies carried out by CSRFI in 1991-98 confirmed again well-known position on tremendous impacts of Volga drainage on biological productivity of the sea in general and showed that division of the sea into Northern, Middle and Southern Caspian Sea is rather conditional from the point of view of bioresources formation, especially for migrating species of fishes and seals. Biological resources of Caspian Sea are part of single ecosystem and formed under effect of single set of factors: volume and qualitative content of fresh water drainage ingested in the sea, sea level, natural fish reproduction conditions, scale and efficiency of artificial fish breeding, fodder productivity, intensity of commercial extraction and toxicological status of the reservoir.

Intensification of rivers and sea contamination with hydrocarbons, phenols, chlorine-organic pesticides, heavy metals and also broadening of the scale of illegal catch led to a critical situation, in which fishery importance of the basin can be absolutely lost. Reserves of major commercial object – sturgeon have considerably decreased. Each year, the efficiency of their natural productivity in all rivers of the basin, scale of fingerlings releases at hatcheries is also decreased, because of insufficient numbers of reserved reproducers.

At the present time, the only way to save unique Caspian ichthyofauna is consolidation of efforts of all literal states – Azerbaijan Republic, Republic of Kazakhstan, Russian Federation, Turkmenistan and Islamic Republic of Iran – on the basis of harmonized actions on protection, reproduction and rational utilization of marine bioresources. It is necessary to develop and implement measures for reduction of hydrocarbons and herbicides contamination in Caspian basin, untreated wastes discharges from industries; to ensure fisheries water discharges for effective natural fishes reproduction and amelioration of spawning places; to continue to release fingerlings grown at hatcheries in the reservoir, implement fishery science recommendations on increasing of efficiency of artificial reproduction; to implement effective measures for eliminating illegal catch.

Major principles of operation of commercial objects in the reservoir should be identified in international “Agreement” on preservation and utilization of bioresources of Caspian Sea, ratified by all riparian states, and commercial catch of fishes and marine animals should be implemented in accordance with common basin Fish Catching Rules, in rigorous compliance of limits and projections, developed on the basis of scientific researches. The main principle for distribution of catch limits should be based on contribution of each state in reproduction of certain specie.

At present, CSRFI is the only institute in Caspian region, which possesses not only data on ecosystem status and biodiversity of the sea for many years, but also annually, carries out expeditionary works for studying hydrologic and hydrochemical regimes, toxicological conditions, fodder basis and fish nutrition, fish populations estimates and fishes distribution.

In light of ongoing changes of environment and commercial objects stocks tied with sea level rise, it is necessary to conduct transcaspian hydro-biological video shooting using facilities of all riparian states. Last years, due to lack of funding and scientific-research vessels number and coverage area of sea cruises have decreased, regular monitoring of natural reproduction of sturgeons in all rivers of the basin, except Volga and Ural rivers, has been terminated. In the period of keen deterioration of conditions and reproductively efficiency of valuable migratory fish species (sturgeon, salmon, herring), strengthened control of commercial bioresources extraction is vital. That is why, it is particularly important to continue many-year integrated researches in the reservoir, on the basis of which, fishery institutes develop catch forecasts and proposals for recovery of high biopotential of Caspian Sea.

Supporting main directions of activities and working plan of Caspian Regional Thematic Center on Biodiversity Preservation, it should be mentioned that prospective aspects of cooperation with other CEP Centers are omitted in the plan, namely with Russian Centers: Center for Legal and Juridical Issues and Center for Sustainable Management of Commercial Bioresources.

Caspian Sea, together with nether parts of rivers flowing in it is the most important fishery reservoir. It is particularly valuable, in terms of sturgeons, whose catch makes about 80% of their world catch. Representatives of the most valuable salmons – unique black sea roach and caspian salmon, inhabit in Caspian Sea, whose stock is maintained only due to efforts of hatcheries. Commercial catch of seal is also essential.

With the purpose to preserve and increase population of unique school of sturgeons and creation of conditions for their sustainable commercial catch, it is necessary:

• To streamline signature of “Agreement on preservation and utilization of bioresources of Caspian Sea” by all literal states.
• To Adopt and implement in all riparian countries governmental decrees on measures for strengthening combat with poachers, contemplating introduction of state monopoly on catch, processing and sale of products made from sturgeons, involvement enforcement bodies for protection of fish resources.
• To undertake measures on prevention of rivers and sea contamination with hydrocarbons, waste water discharged by industries and agricultural lands.
• To implement measures ensuring scale needed for natural reproduction (passage of reproducers to spawning places, amelioration of spawning places and so on);
• Increase releases of fingerlings up till 150 millions pieces per year, plan to transport significant number in the sea and its dispersal in the most nutritious areas.
• Set up (or reestablish) protection areas at the mass fattening and reproduction spots, prohibiting (or limiting) there all types of economic activity affecting on fish resources.

With the view to preserve and reproduce fish stocks of Volga-Caspian basin, Cabinet of Ministers of Russian Federation issued decree N78, dated on 31.01.75 declaring northern part of Caspian Sea including Volga river delta within territory of Russia to be protected territory of Russia.

However, present changes of the status of Russian protected area allows economic activity connected with exploration and production of crude hydrocarbon on the water area of this zone, although they must observe special ecological and fishery requirements.

Astrakhan biosphere state protected area plays an exclusively important role for preservation of biodiversity of Caspian Sea. The status of this protected area is nature protection, scientific-research establishment. The protected area is included in international system of biosphere reservations, implementing global environmental monitoring. Astrakhan protected area is assigned tasks related to preservation of biological diversity: maintenance of protected nature complexes of Volga delta in natural status, execution of environmental monitoring, dissemination of environmental knowledge and conduction of scientific researches.

With the purpose to conserve nature complexes of Kizlar Gulf of Caspian Sea and Sarikum Dune in natural status, including animals and plants recorded in Red Books of Russia and Dagestan, there was established State Nature Protection Area “Dagestanian” in 1987.

Wetlands of low parts of Volga’s delta are related to the most vulnerable and valuable areas of Russian coast.

Russian Federation, as member-state of Ramsar Convention on Wetlands mainly internationally important as water-fowls ecotopes, announced in 1975, 650 thousands of hectares of wetlands surrounding Volga mouth, as lands having international importance. At the present time, the square of wetlands of Volga’s delta is equal to 1.1 millions hectares.

The decree N1050 issued by Russian Federation government on 14.04.94 defined 35 wetland plots of international importance, some of them, in particular “Volga’s delta”, have important geopolitical value.