Keel survey in the waters of the Northern Caspian

 

These studies are of great importance and have been conducted annually since the late 1950s, allowing us to establish the indices of the anchovy, common and big-eyed sprat stock. The goal is to assess the qualitative structure, spatial distribution and abundance of sprat to calculate the forecast of the recommended catch.

 

The work carried out in the Caspian Sea was comprehensive, including an assessment of the yield, monitoring the state of sprat populations using biological, physiological-biochemical, parasitological and microbiological indicators, studying the conditions of feeding and the level of accumulation of toxicants. An analysis of abiotic factors influencing the formation of the population of individual generations of sprat was performed.

 

During the sprat cone survey, areas of the western and eastern parts of the Middle Caspian were studied at depths from 50 to 400 m. A total of 33 light cone stations were completed. At all stations, depth, air temperature, wind speed, water temperature, salinity, etc. were measured. The studied aquatic biological resources were subjected to biological analysis, some samples were delivered to the shore for subsequent office processing, samples of zooplankton, phytoplankton and mnemiopsis were collected. In addition to the cone survey, hydroacoustic observations were carried out, the purpose of which was to quantitatively assess fish concentrations and their biomass density with spatial distribution within the surveyed water area. Also, along the route of the vessel, a count of the Caspian seal was carried out.

 

The collected material is being processed and will be used to determine the total and commercial stock of Caspian sprats for this year and for the near future.

 

Press service of VNIRO