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Freshwater Organisms in Pixels  Fish of the Amur River                                                                                                                                     Introduction


            Great Khentii Mountain Range, and flows   Chono, Mukhar, Guun, Azarga, and Khana                                     of species and many ecosystem types. This   compared to many other Asian countries.
            1,090 km within Mongolia. This river drains   rivers. The Shud and Gal rivers both flow into                         vast area is famous for rare waterfowl, big   The wetland resources of eastern
            into Lake Hulun (Dalai Nuur in Mongolian)   a large inland depression to create Yakhi Lake,                          cats, large ungulates, and endemic fishes.   Mongolia have been subjected to only very
            in China. The Kherlen River flows mostly in   an endorheic basin. The water volume in Yakhi                          The biological richness is explained by the   low levels of exploitation, and so remained
            the steppe region where there are very few   Lake increased in the early 1960s to 97 km2,                            great diversity of landscapes such as dry   relatively undisturbed. This is due not only to
            tributaries, and the river has runoff loss only in   but in recent years the water level and volume                  steppe, grassland, mixed broadleaf-coniferous   the low population density, especially around
            its downstream reach.                    have both declined. The most prominent                                      forest, taiga etc., and high level of landscape   lakes in the semi-arid region, but also to the
                  Within Mongolian territory, another   closed basin is formed by the Ulz River, which                           diversity in this basin are largely the result   fact that traditionally fish and waterfowl have
            large river is Onon, which originates on the   drains into Torey Lake in Russia. The total basin                     of historic and spatial variability in conditions   not been a source of food for the Mongolians.
            northeastern slope of the Khentii Mountain   area is about 35,000 km2 and total length is                            across the region. Altitudinal variation and   This is probably because there is already an
            Range with a total river basin area of 96,200   420 km. Annual mean discharge is 7.7 m3/sec                          horizontal zonation also help form numerous   abundant supply of protein in the form of stock
            km2, of which 30,000 km2 are located within   at Ereentsav station in Mongolia, and in some                          biogeographic sub-regions. Situated on the   such as sheep, cow or horses.
            Mongolia. The total length of the Onon River is   high flow years the river discharge may reach                      eastern rim of Eurasia and abutting the Pacific   However, during the last three
            808 km, and it flows 298 km through Mongolia   up to 575 m3/sec.                                                     Ocean, the basin is subject to the combined   decades the agricultural production and
            in a northeastern direction before entering    Lakes in the eastern Mongolian steppe                                 effects of  monsoon climate conditions,   industrial development are simultaneously
            Russia.                                  and throughout the western part of the Amur                                 oceanic currents, and mountains that direct air   intensified, which influenced on the nature and
                  A small section of the Khalkh River   river basin are characterized by dramatic                                circulation patterns. The geology and terrain,   environment, including wetlands in eastern
            (Khalkhyn gol or Halh) in the far east of the   fluctuations in volume and area. Often they                          with numerous mountain chains separated by   Mongolia. Most important and influential form
            country, briefly flows from China through   are dry depressions, sometimes with salt                                 lush valleys, present a variety of microclimate,   of land use is the raising of domestic livestock
            Mongolia before re-entering China. This river   marshes. The total area and volume of lakes                          soil, and vegetation conditions. These have   (cattle, horses, sheep, goats and camels)
            originates from the western slopes of the   and  wetlands  in  Mongolia also  changes                                yielded a broad range of landscapes and   based on wild pasture. Eutrophication caused
            Great Khyangan Mountains in China and is   according to climatic cycles.                                             unusually high levels of species diversity for   by the inflow of nutrients from domestic and
            shared with Mongolia. The Nömrög (218 km)      Buir Lake (Buyr Nuur or Bei’erhu) is the                              temperate latitudes.                     industrial wastes, and indeed from intensive
            and Degee Rivers (56 km) are the largest   largest lake in the Mongolia part of the Amur                                                                      agriculture, would eliminate the fish and other
            tributaries of the Khalkh River. Basin area of   basin and the fifth largest lake in Mongolia. The                   Cultural characteristics of Mongolia     aquatic animal communities replacing with
            the Khalkh River is about 25,000 km2 and the   lake is located in the transboundary area of                                Mongolia is a country with well-   only few pollution resistant species.
            Mongolian part of the basin covers 14,000 km2.   Mongolia and China, and is fed by the Khalkh                        developed animal husbandry, mainly pastoral   Also, the settled agriculture, especially
            Total length of the river is 399 km, of which   River. Water surface area of the lake is 615                         livestock breeding. From ancient times, the   cultivation of dwarf varieties of wheat is
            264 km flow through Mongolia. The Sharilj   km2, and maximum depth is 10.4 m. The lake                               livestock were mainly used for food, goods,   recently gaining importance in eastern
            River separates from the Khalkh River just   basin area is 25,000 km2 and mean volume of                             consuming materials, traveling etc., hence   Mongolia. Industrial development and related
            before entering Buir Lake (about 32 km from   the lake is 3.8 km3. In low flow years, mean                           there are many legends, true histories about   activities such as coal-mining, useful mineral
            river delta), and drains into Dalai Lake via the   depth is about 5.7 m with a volume of 3.5 km3.                    the relation of man and livestock, especially   extraction, building of different types of roads
            Orshun (Orxon) River. Annual mean discharge   In high flow years the mean depth increases                            that with horses. However, there is almost   and power plants are confined mainly to the
            of the Khalkh River at Sumber station is just   to nearly 7 m with a corresponding increase                          no antediluvian information about the relation   regions with fragile ecosystems and great
            over 18 m3/sec. Average annual discharge of   of volume to 4.3 km3. In China, the Orshun                             among man and fishes or other aquatic    conservation values, such as river or lake
            Orshun River into Dalai Lake is 0.69 km3 (21.9   River originates from the lake delta and drains                     organisms in this country. As part of this   basins, forests, wetlands etc.
            m3/sec).                                 into Dalai Lake, and thus the northeastern part                             culture, conservation and the appropriate use   The hunting pressure on fish and
                  All these larger rivers typically flow   of lake water is fresher. Lake mineralization                         of natural resources are strongly encouraged.   waterfowl was insignificant in the previous
            through Mongolian steppe grasslands in their   varies from 180 mg/l in a high flow year to                                 In relation to the size of the land area,   time due to ancient tradition of the protection
            lower reaches and mountainous taiga forests   375 mg/l in a low flow year. Buir Lake is very                         the human population in Mongolia is very low,   of animals and other natural resources.
            at their sources, which include the Khentii   rich in plankton, benthic invertebrates, and                           and as more than one third of the population   However, since three decades following the
            Mountains (Onon and Kherlen rivers), and the   other aquatic biota, and is one of the most                           lives in the capital city, the population density   free-market economic change in Mongolia, the
            Great Khyangan Mountains (Khalkh River) (Kaus   biologically rich lakes in Mongolia, where 29                        over most of the country is considerably   influence of traditional approach is declined,
            et al. 2023).                            species of fishes inhabit (Simonov & Dahmer                                 less than one person per square kilometer.   and wildlife was increasingly hunted, and the
                  The Mongolia basin has a number    2008).                                                                      Therefore, until the recent few years there   pressure becoming extremely high. The recent
            of small, short rivers, many of which are      The  Amur River basin is rich in                                      was very little disturbance in terms of human   development of the fishery resources may
            frequently dry. These include the Shud, Gal,   biological diversity and supports thousands                           population pressure on natural ecosystems   reduce the important fish species, such as


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