No abstract

Aim. The aim of the study is to analyze the current state of artificial reproduction of the Caspian sturgeon and to identify the problems of reducing efficiency and ways to solve them.Discussion. The current critical state of the Caspian sturgeon, which accounts for up to 90% of the world's related resources, is of concern to the entire community, due to the threat of extinction of these relic individuals  on  the  planet.  This  can  be  prevented  by  increasing  the efficiency of reproduction. However, natural reproduction is practically reduced to zero, so the real and only possible solution is artificial reproduction. This analytical review presents five tasks, the successful solution of which will improve the current state of artificial reproduction in the Volga‐Caspian basin. The main task is the provision of fish breeding processes with producers, which, in the absence of fish of natural generation, are derived from brood stocks. Of particular concern is the threatened  state  of  the  Caspian  beluga  and  stellate  sturgeon.  It  is necessary to increase the release of their juveniles, for which financial stimulation of this activity is necessary. It is necessary to move more actively to the release of juveniles of an enlarged (7‐10 g) size and their export to feeding places in the waters of the Northern Caspian, which will contribute to an increase in fishing return.Conclusion. It is necessary to increase funding for research into the reproductive function of females and for artificial generation, as well as for the maintenance of production herds – a golden fund for restoring natural reserves. The attention of all the Caspian states should be drawn to the intensification of activities for the artificial reproduction of these unique fish species in the Caspian basin.

Aim. This study was an attempt by the authors to identify the impact of oil production in the Caspian Sea on the quality of waters surrounding oil and gas-production platforms.Material and Methods. In 2018, by order of the Committee for Forestry and Wildlife of the Ministry of Agriculture of the Republic of Kazakhstan, Kazekoproekt carried out comprehensive marine research to assess the state of biological resources in the eastern part of the Caspian Sea. All studies were carried out according to standard methods accepted in international practice. Samples were collected in summer (July-August) 2018 and autumn (September) 2018.Results. An analysis of the materials of environmental studies carried out in the water area of the eastern part of the Caspian Sea in 2018 established the absence of biogenic concentrations in sea water in excess of the standard indicators. It was found that in the waters surrounding several stations in summer and autumn, concentrations of oil products were exceeded. The concentrations of pesticides in the waters of the northern Caspian Sea recorded in 2018 were not detected.Conclusion. It was found that in the eastern part of the Caspian Sea in 2018 there was no concentration of biogenic elements in sea water above the standard indicators. Of the heavy metals, an excess of maximum permissible concentrations was found only at one station - of copper in the summer over 159 sq. m and in the autumn over 121 sq. m. Of particular concern is the fact that at several stations in summer and autumn excessive concentrations of petroleum products were recorded. The concentrations of pesticides in the waters of the northern Caspian Sea recorded in 2018 were not detected.

Aim. In the present work we investigated the circulation of AIV in wild bird populations and studied the sorption of the influenza virus in the feathers of wild waterfowl nesting on reservoirs during the autumn mass migration. Material and methods. Sampling was carried out on the territory of the Novosibirsk region on Lake Chany during the period from August to September 2014-2016. Biological samples were collected from 188 wild waterfowl of various species. AIV isolation from cloacal swabs and swabs collected from feathers was carried out in the developing chick embryo system (RCC) as previously recommended. The isolated viruses were tested by HA/HI with specific sera, PCR analysis was carried out with subtyping primers. The genomes of the isolated viruses were sequenced for phylogenetic analysis. Results and discussion. As a result of monitoring, cloacal and feather swabs were collected from 188 individuals belonging to 13 species of the Anseriformes and Charadriiformes, whose representatives are the main natural reservoir of AIV. Fifteen new AI viruses were isolated from the collected samples. Four of them were isolated from plumage samples and the rate was more than 2 times lower, compared with virus isolation from cloacal swabs. Main conclusions. Thus, it can be assumed that avian influenza virus transmission by plumage during migration is not sufficiently taken into account. The key role in AIV ecology may play the virus spreading by its adsorption on bird feathers.