Conducting comprehensive studies of water bodies in the Astrakhan region in the locations of operating fish farms

 

For example, these are different hydrological conditions on large (Volga River, Bakhtemir River, Bolda River, etc.) and small watercourses (eriks, channels) of the lower reaches of the Volga. In the first case, the organization of fish farming on a water body with good flow, depth and hydrochemical regime is limited by the presence of shipping, as well as the movement of ice when it melts in the spring and the high speed of the current during the flood period, leading to the demolition of cages. The formation of fish breeding sites (FBS) on small watercourses is limited by low depths, weak flow and intense hydrochemical regime, and the sanitary condition of such water bodies.

 

Due to this feature, the depth and speed of water masses are subject to significant seasonal changes with a decrease in values ​​during the low-water period on certain small watercourses, which is critical for fish farming.

 

The Astrakhan Region is located in the south of the country. In the summer period, there are an average of 56 days when dry weather and sweltering heat are observed with an air temperature of 30º C or more. The tendency for temperatures to rise and arid conditions contribute to the shallowing of rivers, and a relatively long period of elevated temperatures can affect the condition of aquaculture objects grown in natural watercourses.

 

The water quality of natural watercourses in the region also does not always meet the requirements of the aquaculture objects grown.

 

In order to assess critical aspects of the hydrological and hydrochemical regime and sanitary conditions, which allow reducing possible risks of fish farming at the planning stage of cage farming, specialists of the commercial aquaculture sector of the Volga-Caspian branch of the Russian State Research Center "All-Russian Research Institute of Fisheries and Oceanography" (VNIRO) continue to study water bodies of the Astrakhan region in the locations of operating fish farms.

 

During the studies, scientists determined the depth, flow rate, water temperature, dissolved oxygen content, the amount of suspended, organic, biogenic substances, a number of sanitary and microbiological parameters, including the presence/absence of pathogens of aeromonosis, pseudomonosis of fish. The quality of the environment was assessed based on the biotic index.

 

The conditions in the studied areas for certain environmental parameters were not optimal for the effective functioning of fish farms. The facts of the presence of zones with shallow depth, low flow rate and dissolved oxygen content, increased amount of organic matter, unsatisfactory sanitary conditions, low intensity of self-purification processes and faecal pollution were noted.

 

In the presence of suitable areas of watercourses for the placement of cage farms, there are also those where the conditions are far from normal. Careful studies at the stage of pre-project studies will allow a more rational approach to the selection of water bodies when forming the RWS, adjust their boundaries taking into account the characteristics of specific sections of watercourses and, ultimately, reduce the risks of fish farming activities of new cage farms.

 

Press service of VNIRO