Lake Zaysan is undoubtedly one of the oldest bodies of water on the planet. Its exact age is so difficult to determine. According to some indirect signs, scientists suggest that the reservoir was formed at the end of the Cretaceous period, more than 65 million years ago, and therefore dinosaurs graced its waters. If this hypothesis is correct, then the Zaysan may be even older than Lake Baikal, whose age, according to the common opinion, is about 25 million years.
But even if the lake is younger, it will hardly change the attitude of the Kazakh people. For the people of the country, the Zaysan-Nor is a sacred place. Its icy waters witnessed all the historical events that took place in the eastern part of modern Kazakhstan, at the foot of the Altai, Kalba, and Tarbagatai ridges.
There are many theories how the name Zaysan originated. Some researchers, emphasizing the noble status of the reservoir, believe that the source is the similary-named title of Oirot khans. Some scientists lean towards the translation “rich fish lake” from the Mongol-Oyrotish language. However, it became “Zaysan” only three centuries ago, when these places began to be developed by Russians. Previously, the local people called it Kyzyl-Pu, Corcan, and Hostu-Nor (“lake of the bells” in connection with the melodious sound of its surf). By the way, the surf, which never disappears from the surface of the lake, leaves traces in the vicinity of the reservoir, allowing it to state that the ancient Zaisan was much bigger than the one seen today!
And even now, after reducing the surface area, the lake is the largest natural reservoir of fresh water in Kazakhstan. The oval basin of the Zaysan stretches from the South-East to the North-West for more than a hundred kilometers. The width of the reservoir varies from 22 kilometers in the North to 48 kilometers in the South. Despite the shallow depth of 15 meters, the lake is a habitat for huge populations of animals and plants. It is famous for excellent fishing all over the country. Carp, ide, pike-perch, pike, and burbot dwell here yet is not a complete list of species that live in this ancient reservoir, there are in total over 23 fish species.
The banks of the Zaysan densely overgrown with reeds, shelters a variety of birds. Some species do not stay here, using the Zaysan as a place to stop for long flights. Representatives of the rye and chibis families can often be seen on the lake.
In 1960, Lake Zaysan became part of the Bukhtarma reservoir, which is now one of the five largest reservoirs of artificial origin in the world. The creation of the reservoir was done by flooding the Irtysh River valley at the place of its appearance from the Zaysan.
Modern man has shamelessly intervened in the biosphere of the lake. A hundred years ago, you could meet a herd of Przewalski horses or two-humped camels on the banks of the Zaysan. Even tigers were found here. But now, due to the active development of the surrounding areas, the construction of the Bukhtarma hydroelectric power station, which changed the water level and the boundaries of the lake, the life of the inhabitants of the reservoir has changed. Tigers and horses, valuable commercial fish: sturgeon, taimen, and nelma all disappeared. The population of the great bustard and the saiga, carp, and zander fish has significantly decreased.
One of the main feeders of the lake, the river Black Irtysh (Artsisyhe) flowing from China, is a great danger to the waters of the Zaysan. Collecting untreated sewage in China, it bears salts of heavy metals, and waste from the processing of petroleum products to the East-Kazakhstan region.
Poaching is also flourishing on its shores. According to some reports, about 25% of the fish in the lake are caught illegally. This is due to the high level of unemployment in the region. Local residents are forced to apply to the breadwinner – the Zaysan beyond measure, as other sectors of the economy are not well developed in addition to fishing. In addition, the Russian-Chinese border, which creates a high demand for fish resources, is just a few dozen kilometers from the lake.
Perhaps the only safe way to improve the economic situation in the region is the development of ecotourism. Beautiful mountain scenery, blue lake surface, and beautiful fish species are able to attract lovers of outdoor activities to these places. In the vicinity of the Zaysan, there are three hundred sunny days per year; the water temperature is on average +22°C in summer.
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Lake Zaysan (Kazakh: Зайсан көлі, Zaısan kóli, زايسان كؤلئ, Kazakh pronunciation: [zɑjˈsɑn kɵˈlɪ]; Mongolian: Зайсан нуур, Zaisan nuur, en: Noble lake; Russian: Озеро Зайсан, Ozero Zajsan; simplified Chinese: 斋桑泊; traditional Chinese: 齋桑泊; pinyin: Zhāisāng Pō, Xiao’erjing: جَىْصْا پْ; Dungan: Җэсонпә) is a freshwater lake, ca. 1,810 km² (700 mi²), in eastern Kazakhstan, in a hollow between the Altai and the Tarbagatai Mountains. It is the largest lake in the East Kazakhstan Region.
The lake lies at an altitude of 420 m, is 105 km long and 22–48 km wide, with a maximum depth of 15 m. Its major tributaries are the Kara Irtysh (Black Irtysh) and Kendyrlyk from the east; its only outlet is the Irtysh River (or White Irtysh). The lake is generally frozen from the beginning of November to the end of April, but still has an abundance of fish. Since the construction of the Bukhtarma dam on the Irtysh downstream from the Zaysan, the lake has risen 6 m (20 ft) above its natural level. As the result, the area of lake essentially increased (nearly doubled: from about 1,800 km² to 3,500 km², or even to 5,000 km²), thus, in some sources the lake is indicated as part of an artificial reservoir.
Lake Baikal is often considered the most ancient lake in the world, as clear evidence shows that it is 25–30 million years old. Lake Zaysan, however, may be even older, dating possibly from the Cretaceous period with a likely age in excess of 66 million years old (most probably around 70 million years), although its exact age is controversial and labelled with some uncertainty. A direct indication of the Lake Zaysan’s age is hard to find, although some geological studies of the Zaysan Basin have been reviewed. Artificial reservoirs cover large surrounding areas. Modern geological analysis of the entire field, apparently, supports an exceptionally old age for Lake Zaysan.
History
The first Russian to reach the area was Ivan Bukholts who ascended the Irtysh to build a fort and search for gold. In 1715 he was driven back downriver by the Oirats, who had established the Zunghar Khanate in the region.
The Chinese Qing Empire conquered the Zunghar state in the 1750s. This prompted an increase in the Russian authorities’ attention to their borderland; in 1756, the Orenburg Governor Ivan Neplyuyev even proposed the annexation of the Lake Zaysan region, but this project was forestalled by Chinese successes. Concerns were raised in Russia (1759) about the (theoretical) possibility of a Chinese fleet sailing from Lake Zaysan down the Irtysh and into Western Siberia. A Russian expedition visited Lake Zaysan in 1764, and concluded that such a riverine invasion would not be likely. Nonetheless, a chain of Russian pickets was established on the Bukhtarma River, north of Lake Zaysan. Thus the border between the two empires in the Irtysh basin became roughly delineated, with a (sparse) chain of guard posts on both sides.
The situation on the Zaysan in the mid-19th century is described in a report by A.Abramof (1865). Even though the Zaysan region was recognized by both parties as part of the Qing Empire, it had been annually used by fishing expeditions sent by the Siberian Cossack Host. These summer expeditions started in 1803, and in 1822-25 their range was expanded through the entire Lake Zaysan and to the mouth of the Black Irtysh. Through the mid-19th century, the Qing presence on the upper Irtysh was mostly limited to the annual visit of the Qing amban from Chuguchak to one of the Cossacks’ fishing stations (Batavski Piket).
The border between the Russian and the Qing empires in the Irtysh basin was established along the line fairly similar to China’s modern border with Russia and Kazakhstan by the Convention of Peking of 1860. The actual border line pursuant to the convention was drawn by the Protocol of Chuguchak (1864), leaving Lake Zaysan on the Russian side. The Qing Empire’s military presence in the Irtysh basin crumbled during the Dungan revolt (1862–77). After the fall of the rebellion and the reconquest of Xinjiang by Zuo Zongtang, the border between the Russian and the Qing empires in the Irtysh basin was further slightly readjusted, in Russia’s favor, by the Treaty of Saint Petersburg (1881).
Michael Ruark 
My education continues……I ( like I suppose many others) have no knowledge of lake zaysan – but what I have read about it suggests it is a unique habitat with a long history of sustaining wildlife and humans.
Kasakhstan is a mineral / oil rich state which has the capacity to easily protect this very important lake , not only for eco tourism but as a world nature heritage site.
Thank you once again for a well researched , unusual post