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The results of ichthyological and parasitological studies of the Kureiskoye reservoir are presented. The features of the formation of ichthyofauna during the formation of a reservoir and its industrial use are shown. The ichthyofauna of the Kureiskoye reservoir was formed on the basis of the indigenous fauna of the river. Kureyki. The modern composition of fish includes 22 species. Grayling fish are represented only by the Siberian grayling — Thymallus arcticus (Pallas, 1776). This species has a relatively small number of scales in the lateral line (no more than 95). Grayling is found in Lake Munduyskoye, which on average has about 100 scales. Since Munduyskoye Lake belongs to the river basin Kureyka, we believe that the second species, the black Baikal grayling Th. baicalensis (Dybowski, 1874) is also present. The main processes of its formation took place as in the Khantaskoye reservoir. Currently, the number of salmon and whitefish is decreasing. These groups of fish previously formed the basis of the composition of the original ichthyofauna. Today salmon and whitefish are found in the zone of backwater and flooded tributaries of river channels. The composition and number of whitefishes has changed especially. Tugun practically disappeared, others (peled, wild boil, vendace, and whitefish) began to be found singularly. The dominant role is played by pike, which uses peat islands for its spawning, as well as perch and roach. The transformation of the reservoir led to radical changes in the composition and structure of communities of all groups of organisms in the aquatic biota. This influenced the composition and abundance of fish parasites. The parasite fauna of the fish of the Kureyskoye reservoir is represented by widespread species of helminths. Infection with helminths mainly occurs when fish feed on planktonic crustaceans.

Fisheries research was carried out on the Khantayskoye reservoir in 1977–2020. This article presents the results of these works. In the first years after the flooding of the Khantayskoye reservoir, pike and common species of whitefishes (Siberian vendace, peled and whitefishpyzhyan) constituted the basis of the fishery. The share of other fish (carp, burbot, perch) was insignificant. The sharp increase in the food supply for planktophages and benthophages was short-term. Trophic depression began to appear in the early 80s (3–5 years from the moment the reservoir was filled). From this moment to the present time, whitefish species have a slowdown in linear and weight growth, an increase in the timing of puberty, a decrease in fertility. Of the whitefish fish, only Siberian vendace and whitefish are present in the fishery, the numbers of which have significantly decreased. Since the mid-2000s, the number of peled has decreased significantly and this species of fish has become rare in the reservoir. . Currently, there is a relatively high number of pike. Roach, ide, pike and perch actively mastered the channel of Kontiki, where before was practically absent. The increased number of these species affects the number of whitefish in their spawning areas, and their reproduction, including the safety of eggs.The parasite fauna of the main commercial fish species of the Khantayskoye reservoir was investigated. The most pathogenic were myxosporidia Henneguya zschokkei (Gurley, 1894), the causative agent of peptic ulcer disease in whitefishes.

At the end of April 2020, the largest man — made disaster in the Russian Arctic occurred-a diesel fuel spill in Norilsk. Oil products on the Ambarnaya river got to the lake. Pyasino (source of the river of the same name). To determine the extent of damage to the aquatic ecosystem of the Pyasina basin, it is necessary to know the nature and direction of previous research in the fisheries field. The aim of the work is to analyze the available open source publications in the field of fisheries research in the Pyasina basin. The history of ichthyological and hydrobiological studies of the Pyasina river basin (a large watercourse on the Taimyr Peninsula) is considered. Information is provided that the basin of this river is poorly studied in terms of fisheries due to its location beyond the Arctic circle. The chronology of fisheries research from the Foundation of the Yenisei ichthyological laboratory (Krasnoyarsk) in 1908 to 2020 is given. It is noted that the greatest interest in studying the basin of this river is shown in connection with the development of the Norilsk mining and metallurgical combine and the organization of the Federal state budgetary institution «United Directorate of Taimyr reserves». The role of individual scientific organizations in the study of water ecosystems of the Pyasina river basin is shown. The most significant contribution to the fisheries survey of the river basin was made by the Siberian scientific fisheries station (now the Krasnoyarsk branch of the all-Russian research Institute of fisheries and Oceanography), MSU, TSU. The publications of employees of these organizations contain materials on the study of phytoplankton and zooplankton, zoobenthos, their production characteristics, the biology of a number of species, the Stingray of larvae, features of the development of semi-passable ichthyofauna, materials on the genetic features of individual populations of whitefish, biological and morphological features of whitefish and char fauna, fish Parasitology, the content of polyunsaturated fatty acids, and others. Information is provided on the number of zooplankton species and forms, including 28 forms. It is shown that the composition of the ichthyofauna of the river basin to date, 38 species of fish are known.

Species composition and abundance of zooplankton and zoobenthos of large Norilsk Lakes (Lama, Sobach’e) and Kutaramakan Lake in the western part of the Putorana plateau were studied in August-September of 2013–2014 after a long gap. Senecella calanoides Juday (Copepoda: Calanoida) in zooplankton and 5 species of water mites (Acalyptonotus violaceus Walter, Hygrobates (Hygrobates) foreli (Lebert), Lebertia (Mixolebertia) densa Koenike, Lebertia (Pilolebertia) porosa Thor, Oxus (Gnaphiscus) setosus (Koenike) (Hydrachnidia)) in zoobenthos were recorded for the first time in the investigated lakes. A total of 64 taxa of benthic invertebrates were found, of which 42 taxa were Chironomidae. Zooplankton species composition of Lama and Cobach’e lakes was similar and differed from that of Kutaramakan lake by presence of Senecella calanoides and Limnocalanus macrurus Sars (Copepoda: Calanoida). In zoobenthos of Kutaramakan lake amphipods were not found. Lama and Kutaramakan lakes can be classified as ultraoligotrophic water bodies based on biomass of zooplankton and zoobenthos. Among the studied lakes, Cobach’e lake has the greatest biomass, and based on the biomass of zooplankton in some zones of > 0.5 g/m3, it is an oligotrophic water body, and based on an average biomass of zoobenthos 3.85 g/m2 an α-mesotrophic one

The sterlet (Acipenser ruthenus Linnaeus, 1758) is a relatively small sturgeon widely distributed in Eurasian rivers from the Danube to the Yenisei. During the twentieth century, all wild sterlet populations have declined due to anthropogenic factors including: overfishing, poaching, construction of dams, and pollution. Despite the necessity of characterization both wild and captive stocks, few studies of population genetics have been performed thus far. Here we studied the genetic diversity and geographic structure of sterlet populations across the eastern range – Ob-Irtysh and Yenisei basins – by sequencing a 628-bp fragment of mitochondrial DNA control region. We identified 98 new haplotypes, delineated 12 haplogroups and estimated the time of basal haplogroup divergence within the species as over 8 million years ago. Our data suggest that Ob-Irtysh and Yenisei populations are isolated from each other and much lower genetic diversity is present in the Yenisei population than in the Ob-Irtysh population. Our data imply that sterlet populations in Siberian rivers underwent bottleneck or fragmentation, followed by subsequent population expansion. The data obtained here are important for sterlet population monitoring and restocking management.

We compared the composition and content of fatty acids (FAs) in fish with different feeding habits (sardine (least) cisco Coregonus sardinella, goggle-eyed charr (pucheglazka) form of Salvelinus alpinus complex, humpback whitefish Coregonus pidschian, broad whitefish Coregonus nasus, boganid charr Salvelinus boganidae, and northern pike Esox lucius from an Arctic Lake. Feeding habits of the studied fish (planktivore, benthivore, or piscivore) significantly affected the composition of biomarker fatty acids and the ratio of stable isotopes of carbon and nitrogen in their biomass. The hypothesis on a higher content of eicosapentaenoic and docosahexaenoic acids in the fish of higher trophic level (piscivores) when compared within the same taxonomic group (order Salmoniformes) was confirmed.