The Central Asia Region is comprised of the countries in the Aral Sea Basin, or more specifically: Turkmenistan, Uzbekistan, Kazakhstan, Tadjikistan, and Krygyzstan. The freshwater fish of Central Asia face numerous threats, many of which are directly linked to those facing the Aral Sea and its tributaries. The drying of the Aral Sea has vast implications on freshwater fish and ecosystem health. Over the past few decades, man-made developments such as irrigation networks have drastically altered the Aral Sea and the entire Central Asia Region. Large-scale irrigation projects during the Soviet era were constructed around both the Syrdarya and Amudarya rivers (two largest in the Aral Sea Basin), which has led to the virtual disappearance of the Aral Sea Some of the effects on freshwater fishes are well-documented; however, there is a dire need for more population assessments, studies, and Red List coverage in the area.
Central Asia’s ichthyofauna face a variety of threats, the most notable being: shifts in water distribution due to irrigation, water salinization, industrial pollution of water areas, and introduced species of fishes (Kreuzberg-Mukhina et al., 2004). While some populations have been minimally affected by these threats, others in the Aral Sea Basin have gone extinct in part due to many of these threats. Major rivers have had a change in fish stocks, with sturgeon, shovelnose and Aral trout virtually disappearing from them. Countries in the region must collaborate on these issues, as “only implementation of a water resource rehabilitation programme could lead to the rehabilitation of fish stocks and fisheries,” (Pavlovskaya, 1995).
The Central Asia region of the FFSG is home to such countries as Kyrgyzstan, Tadjikistan, Turkmenistan, Uzbekistan and the south of Kazakhstan. The region is closed in by high mountains from the south and east and fully open from the north and west. It is situated on the southern part of a temporal climate zon. About 70% of Central Asia territory is comprised of plains with single rivers, which lose water because of evaporation and disappear. Even such big rivers as the Zarafshon and Kashkadarya face this plight. Only the biggest rivers can run through many hundreds kilometers of deserts and reach large closed lakes. The Amudarya and Syrdarya reach the Aral Sea. The Ili reaches Lake Balkhash. Central Asian mountains (30% of regional area) are full of branching river systems. There are more then ten thousands rivers in the mountains of the region.
Climate is extremely continental and dry. Summer is hot and arid, with average monthly temperatures from 25-31oC, though often temperature is about 40oC at day time. Winter is relatively wet, sometimes with strong frosts. Cold Siberian and Arctic airs easily enter Central Asia from the north. Average monthly temperatures vary. For example in Uzbekistan temperatures range from -6oC to +2oC. The region is overall very arid. For 20% of the region, precipitation amounts to less than 100 mm/year, and less then 300 mm/year on 80% of the region. Almost all (approximately 95%) of the rain entering the area comes from outside of the region, which is a significant source of water income.
Central Asia is divided to several independent closed basins that have no flow connection between each other. These include: basins of Lake Issikkul, Lake Balkhash, and the Aral Sea, as well as the rivers of Turkmenista. The Aral Sea basin is the biggest and is situated in the centre of the region. It includes basins of such rivers as Amudarya and Syrdarya.
The biological diversity of this region is relatively high for its geographic zone, or at least was before the Aral Sea, Syr Darya, and Amu Darya rivers began to dry up. Central Asia is home to approximately 120 fish species (Kreuzberg-Mukhina et al., 2004). As of 2004 the Red Books of the Central Asian countries of the region list 30 species of fishes.
Central Asia is very specific region from a zoogeographical point of view. The “mountainous area” refers to the High Mountain Asia sub-region of the Holarctic region. Very specific and extremely inclement environments of the high mountains have led to the creation of original fauna. The High Mountain Sub-region is characterized by poorness of species, high endemism and originality of fish genera.
The Plains area of the region lies in the Ponto-Caspian-Aral province of Mediterranean sub-region within Holarctic region (Berg, 1949; Turakov, 1963; Nilolsky, 1971). Fishes from different zoogeographical regions are mixed along regional borders. Several fish species naturally entered the Plains region from north (Siberia) and west (Western Asia). As a result ichthyologists marked representatives of several faunistic complexes in the fauna of Central Asia. In the Aral Sea Basin, for example, fish complexes include the following: plain boreal (pike, roach, Syrdarya and Zarafshon daces, gudgeon, Aral spined loach, minnow), sub-mountain boreal (Turkestan sculpin), ancient tertiary (Aral sturgeon, shovelnoses, common carp, wels, pike-asp), freshwater pontain (rudd, asp, common bream, white-eye bream, razorfish, Aral and Turkestan barbels), high-mountain Asian (marinkas, osmans, beardies, sharpray, tashkent riffle bleak, Striped bystranka ), and sub-mountain Indian (Turkestan catfish) (Nikolsky, 1971).
Though some data exist regarding the number and distribution of freshwater fishes in Central Asia, the region is in need of a thorough assessment to better understand the current state of its ichthyofauna.
The threats to Central Asia’s freshwater fish are identified as:
• Irrigation construction. Agricultural development in the arid conditions of Central Asia could be done only through the extensive use of irrigation. During 1950-1980s, about 40 reservoirs (total water volume more than 57 km3), more than 150,000 irrigation canals, more than 100,000 drainage canals and 10 lakes for residual water storage (with area about 7000 km2) were created. As a result, rivers were completely stocked for irrigation purposes and flow of water to the Aral Sea dramatically decreased. Since the 1960s the Aral Sea began to dry and to increase in water salinity. The Aral Sea collapsed as fisheries water body in the early 1980s. It once supported 60,000 workers.
Such huge irrigation construction impacted local ichthyofauna. Dams on the rivers blocked up passes to spawning areas for migratory fishes. The irrigation regime conflicts with spawning and larvae development of many fishes. As a result, fringebarbel sturgeon and Aral barbell vanished from local ichthyofauna. All fish populations in the Plains part of the region (common carp, asp, sabrefish, bream, roach, pike-perch, etc.) have created new stocks in all newly constructed reservoirs and lakes for residual waters storage. The quantity of such species as shovelnoses (3 species), pike-asp, zarafshon dace, minnow dramatically decreased as a result of river-channel water bodies. The water in rivers became more clear because of settling in reservoirs; however, those fishes are usually inhabitants of turbid rivers of Central Asia (Nikolsky, 1938; Berg, 1949; Turdakov, 1963; Kamilov, 1973).
• Water salinization. In the three decades from 1961 to 1991 the Aral Sea changed from 10.2 ppt to 35 ppt (Pavlovskaya, 1995). Freshwater fishes cannot handle these levels of salinity and many therefore went extinct. The rivers in the region have also undergone drastic salinization, though for different reasons which include industrial and agricultural pollution of drainages.
• Industrial and agricultural pollution of water areas. The discharge of drainage waters from irrigated fields and industries led to salinization and chemical pollution of rivers. Parts of many rivers have been contaminated by phenols, oil products, heavy metals, pesticides and nitrogen compounds (Pavlovskaya, 1995).
• Introduction of alien fish species. Humans are singly responsible for the introduction of alien fish species in this landlocked region. A one-time introduction was carried out for health care purposes. In 1930s the mosquitofish was introduced for malarial mosquito control from the Caucasus. All other fish introductions were done for fisheries purposes and can be divided to three groups of activity (described below):
– to Aral Sea for improving of commercial ichthyofauna;
– to newly created irrigation water bodies for improving of commercial ichthyofauna;
– to aquaculture (to fish culture ponds).
Fish introductions to the Aral Sea. Several species were introduced to the Aral Sea due to increasing of water salinity. After the 1980s, as water salinity increased local species vanished in the Aral Sea and were replaced by alien species. All 20 endemic fish species of the Aral Sea disappeared except for Pungitius platygaster (Pavlovskaya, 1995). Small amounts of fishes left the Aral Sea for the Amudarya and Syrdarya deltas and are found in catches from time to time.
Introductions to newly created irrigation water bodies. In reservoirs, channels and lakes for residual water storage, ichthyofauna formed from locally available river fauna which was poor with commercial marketable fish. In order to improve commercial ichthyofauna, valuable fish were introduced to the waters (European perch, balkhash perch, plain thicklip loach, spotted loach, etc.). Many coldwater fishes were also introduced to mountain water bodies (sevan trout, peled, sardine cisco, valaam whitefish, rainbow trout).
Introductions to aquaculture. Introductions to aquaculture have had the biggest impact to ichthyofauna of the Aral sea basin. Three periods of introductions can be identified.
Several introduced fishes were identified erroneously. For example the corean sharpbelly, Hemiculter eigenmanni (instead of H. leucisculus), amur bitterling, Rhodeus sericeus ( instead of rosy bitterling), and Hypseleotris swinhonis (instead of Micropercus sinctus) (Aliev et al., 1963; Makeeva, 1976; Vasilieva, Kozlova,1988; Vasilieva, Makeeva, 1988). At first local ichthyologists believed that the mosquitofish Gambusia affinis holbrooki was introduced; now they are divided into two species – Gambusia affinis and Gambusia holbrooki. Both introduced species merit further study.
No introductions of fish species to the water bodies of Uzbekistan have taken place since 1991. Uzbekistan has signed the Convention of Biodiversity and enacted legislation which regulates introduction of new fishes to the country. Now the main tendency is not to introduce new species to wild conditions in order to protect biodiversity of fishes.
The list of fish species in Uzbekistan water bodies includes 44-49 species (Nikolsky, 1940: Berg, 1949; Turdakov, 1963; etc). In the second part of 20th century, local ichtyofauna became strongly affected by two forms of human activity. These were: construction of large-scale irrigation (which changed hydrographic and stock regime of the basin) and the introduction of new alien species.
It should be noted again that ichthyofauna of the Central Asia is very specific. Famous ichthyologists of the ex-USSR considered that many abundant Eurasia fish species have formed sub-species in the Central Asia (especially in the Aral Sea basin) (Berg, 1949; Nikolsky, 1971, Turdakov, 1963). We can mention following sub-species for example: Amudarya trout, Aral roach, Aral asp, Samarkand khramulya, Aral bream, etc. Recently status of some those sub-species was revoked, but we are nor sure that it was done on the basis of research of fishes in the region. Unfortunately ichthyological investigations of full value in the region were dramatically decreased from early 1990s. From the same point of view, there are many questions regarding introduced species. What species of gambusia, goldfish, and sharpbelly were introduced? What is the status and biology of introduced species at present after changing of more then 10-15 generations in new conditions (note, that many of those species are ecologically very adaptable)? Lastly, are modern species as channel catfish, buffalo and some others still inhabiting the region? Ichthyofauna of the region presently need more investigations to fully understand the populations and their complexities.
Prof., Dr. Bakhtiyor Karimov is Head of the Laboratory of “Hydrobiology and Ichthyology” of the Institute of Gene Pool of Plants and Animals of Uzbekistan Academy of Sciences, Tashkent, Uzbekistan. He has a Candidate of Sciences (Ph.D.) degree in biology from the State Scientific Research Institute for River and Lake Fisheries of the Fisheries Ministry of the Russian Federation, Saint Petersburg (1985) and holds a Doctor of Sciences degree in biology from Tashkent State University (1995).
He has been working in the field of ichthyology, ecotoxicology, aquatic ecology, aquaculture and fisheries development on arid and desert areas of the Aral Sea Basin for the past 30 years. In particular, he has studied ecosystems and biodiversity of artificial desert lakes of irrigational origin, such as the Aydar-Arnasay Lake System, Lakes Sarikamysh, Kamishlibash and Shorkol, and the deltaic lakes of the Amudarya River.
His scientific publications (more than 100) have been published in well-recognized journals of the former Soviet Union and of the Commonwealth of Independent States (CIS), as well as in peer-reviewed journals. He has edited international conference proceedings, an FAO aquaculture and fisheries review and a special issue of the scientific popular journal Ecological bulletin devoted to aquaculture and fisheries issues. He has research experience from Europe and Central Asia through a series of short- and longer-term joint research projects. In the period 1995–97, he worked at the Zoological Institute of the University of Hamburg as a fellow of the Alexander von Humboldt Foundation (Germany) on the project “The impact of water pollution on fisheries”. He has coordinated three FAO technical cooperation projects on aquaculture and fisheries (in 2007–2008, 2009–2010 and in 2011) and a German-Uzbek project on sustainable aquaculture development in the Aral Sea Basin (2006–2007). He was a team leader of the EU–INTAS-funded Aral Sea project (2002–2004), and has participated in several other UNESCO and national projects on aquaculture, fisheries and sustainable use of water resources. He has been a member of the Committee on Coordination of Science and Technologies Development under the Cabinet of Ministers of the Republic of Uzbekistan since 2002, Public expert of the Committee on agriculture and water management issues of the Parliament of the Republic of Uzbekistan, and he is also Vice-President of the Zoological Society of Uzbekistan and SETAC (Society of Environmental Toxicology and Chemistry). At present, he is Coordinator and principal investigator of the state-funded project “Development of high productive intensive aquaculture technologies of raising of fish and other hydrobionts based on use of water in irrigation systems” (2012-2014).
His key scientific interests: Fisheries, Hydrobiology, Ichthyology, Aquaculture, Aquatic Ecology, Ecotoxicology.
Institute of Gene Pool of Plants and Animals of UzAS
232 Bagishamal street, Tashkent 100153 Uzbekistan.
Dr. Bakhtiyar Kamilov is a senior researcher in the laboratory of hydrobiology and ichthyology of the Institute of the Gene Pool of Plants and Animals at Uzbekistan Academy of Sciences, Tashkent, Uzbekistan. He obtained his MSc from Tashkent State University (Department of Hydrobiology and Ichthyology) and his PhD from Moscow State University (Department of Ichthyology). He worked as a researcher at the Institute of Zoology and the Institute of Fisheries (later – Institute of Aquaculture). For a long time he was a lecturer in the Department of Hydrobiology and Ichthyology in Tashkent State University.
His research focuses on fish biology in the basin of the Aral Sea as well as aquaculture in Uzbekistan. He has authored and co-authored about 10 manuals and books and more then 80 articles in scientific journals and books. He was a principle investigator and national consultant in several grants through FAO, UNESCO, SGP GEF.
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