scholarly journals DISTRIBUTION OF CASPIAN SPRATS IN THE NORTH-WESTERN PART OF THE CASPIAN SEA (BASED ON RESULTS OF HYDROACOUSTIC RESEARCH IN NOVEMBER 2018)

2019 ◽  
pp. 41-50
Author(s):  
Tatiana Vasilievna Pomogaeva
Keyword(s):  
Caspian Sea ◽  
Water Surface ◽  
Bottom Layer ◽  
Water Area ◽  
Middle Part ◽  
Average Density ◽  
Layer By Layer ◽  
The Caspian Sea ◽  
The North ◽  
Study Results

Since Caspian sprat today is a reserve fishery object, hydroacoustic studies are the main purpose of solving the problem of estimating concentrations, areas and terms of the organization of the Russian marine fishery. A promising fishing area is the region of the middle part of the Caspian Sea, off the Dagestan coast, which has been studied since 2011. As it was found during previous studies, the densest sprat schools form in the autumn period in the bottom layer. The present research focuses on Caspian sprat distribution in the western part of the Middle Caspian in November 2018. Hydroacoustic tacks covered a water area of 630 NM. The echo recordings of hydroacoustic surveys covering the water area at the depths 20-60 m were analyzed. The recordings were studied considering the response of sprat to the day and night light. Processing of hydroacoustic data was carried out in several stages: analytical viewing of echograms purposed to identify specific features of sprat; recording minimum and maximum values of echo intensity depending on the depth; data post-processing in SIMRAD BI-60 program. The distribution of Caspian sprats is represented totally from the water surface to the ground, and layer by layer, in layers of 10 meters from the water surface. It has been stated that in the surface layer there are practically no sprat schools. The maximum value of the average density (8.7 t / mile2) was registered in the bottom layer (40-50 m). The study results can be used in organization of Russian sprats fishing in the Caspian Sea.

scholarly journals FEATURES OF BEHAVIOR OF ORDINARY SPRAT (BY RESULTS OF HYDROACOUSTIC RESEARCHES)

2018 ◽  
pp. 65-73
Author(s):  
Igor Borisovich Balchenkov ◽  
Tatiana Vasilievna Pomogaeva
Keyword(s):  
Caspian Sea ◽  
Water Area ◽  
Early Spring ◽  
Middle Part ◽  
Summer Period ◽  
The Caspian Sea ◽  
Research Ship ◽  
Study Results ◽  
Seasonal Aspect ◽  
Made In

Caspian sprats are reserve target species. The study of species identification of Caspian sprats was carried out on board a research ship “Researcher of the Caspian Sea” using EK-60 hydroacoustic complex having stationary antennas with a split beam of 38 and 120 kHz. The behavior and distribution of ordinary sprats in the western part of the Caspian Sea (Middle part of the Caspian Sea off the coast of Dagestan) was investigated. Echo recordings of hydroacoustic surveys made in 2011-2017 covering the water area with depths from 20 to 300 meters were considered. A database with hydroacoustic research files was created, containing the parameters of the surveys and the graphic display of the echograms. Taking into account the negative reaction of ordinary sprat to light, both day and night recordings were considered. Characteristic echoes of ordinary sprat are described in the seasonal aspect. These studies, describing the nature of the behavior of ordinary sprats, are important for the organization of fishing in the western part of the Caspian Sea. It has been stated that density of sprat shoals during spring-summer period is not high, fishing by bottom trawl is efficient only at the end of August. The most promising sprat accumulations can be found in early spring (March) and in October and November, when sprat is caught in the industrial scale. The study results describing special behavior of ordinary sprats can be used in organizing sprat fishing in the Western part of the Caspian Sea.

scholarly journals Temporal variability of catches, distribution and dynamics of length of Russian sturgeon in waters of the Caspian Sea in 2015 –2020

2021 ◽  
Vol 0 (4) ◽  
pp. 80-90
Author(s):  
Irina Victorovna Konopleva
Keyword(s):  
Caspian Sea ◽  
Adult Population ◽  
Water Layer ◽  
Middle Part ◽  
Russian Sturgeon ◽  
The Caspian Sea ◽  
Bottom Water Layer ◽  
The North ◽  
Shallow Zone ◽  
Heating Up

The paper presents long-term data on catches, distribution and length dynamics of Russian sturgeon in the waters of the Caspian Sea for the summer-autumn periods in 2015-2020. When considering the catches in the different parts of the sea there is found their annual variability, which is especially noticeable in the shallow zone in the North Caspian (0.31-2.0 specimens/trawl) and in the Middle Caspian (0-1.31 specimens/trawl). In the course of determining the reasons for the interannual dynamics of catches there were revealed several decadal rises. The dependence of decadal catches on the temperature of the bottom water layer was analyzed. The highest rise in catches was observed in the first decade of September when the temperature of water lowered up to 20.0-15.0 °C. The increase was observed due to migrating individuals to the shallow zone of the Northern Caspian Sea from shallow waters. Despite the variability of catches, the localization of Russian sturgeon schooling in the northern and middle part of the sea during the summer-autumn periods of 2015-2020 has certain similar features and trends. Sturgeon species fed mainly on shallow banks and deep dumps, where the largest catches of sturgeon were recorded from 5.0 to 12.0 specimens/trawl. The absence of sturgeon at depths of up to 3.0 m isobath in the last five years is due to the water heating up to 27.6-28.8 °C. The decrease in the length of the Russian sturgeon observed in recent years is due to an increase in the proportion of youngsters (19.2-70.0%) against the background of a decrease in the adult population. It should be noted that from 2017 to 2019 there were not found the adult species in the catches by fishing nets, which indicates their continued re-moval from the population.

State of populations and fishing of semi-anadromous fish in the North-Eastern Caspian sea

2021 ◽  
pp. 22 (87)-30 (94)
Author(s):  
Askarbay Kadralievich Kamelov
Keyword(s):  
Caspian Sea ◽  
Water Area ◽  
The State ◽  
Anthropogenic Factors ◽  
Anadromous Fish ◽  
The Caspian Sea ◽  
The North ◽  
Natural Reproduction ◽  
Pike Perch ◽  
North Eastern

Semi-anadromous fish (roach, bream, pike-perch, asp) are the main objects of fishing in the coastal zone of the North-Eastern part of the Caspian Sea. The state of the populations of these fish changes significantly under the influence of natural and, especially, anthropogenic factors, which have increased in recent years. The aim of this work was to study the current state of populations of semi-anadromous fish in the NorthEastern Caspian Sea. Based on the materials of three years of research (2016, 2018, 2020), with the involvement of literary sources, long-term changes in the size-weight and, age indicators, nutritional status of fish and the sex ratio in populations are considered. It has been established that the state of the semi-anadromous fish populations in the North-Eastern Caspian remains tense at the present time. All populations are characterized by general negative patterns of state change. There are tendencies of decrease in size, weight and age indicators, the number of populations and fish catches are decreasing. These changes were least of all manifested in bream (whose state is relatively stable) and were most pronounced in pike perch. The depressive state of the populations is explained by a decrease in the scale of natural reproduction in recent years, due to a decrease in the water content of the Ural River and the number of spawners allowed to spawn on the river. Marine fisheries in the North-Eastern Caspian are concentrated in shallow waters, which increases the fishing load on semi-anadromous fish and prevents their passage to spawning. It is necessary to reduce the pressure of fishing by reducing the number of nets used in the shallow water area of the North-Eastern Caspian and strict observance of the rule of the forbidden pre-estuary space of the river Ural. English version of the article on pp. 87-94 is available at URL: https://panor.ru/articles/state-of-populations-and-fishing-of-semi-anadromous-fish-in-the-north-eastern-caspian-sea/64076.html

scholarly journals TSUNAMI HAZARD ASSESSMENT IN THE CASPIAN SEA

2019 ◽  
Vol 47 (5) ◽  
pp. 74-88
Author(s):  
E. A. Kulikov ◽  
A. Yu. Medvedeva ◽  
I. V. Fine
Keyword(s):  
Hazard Assessment ◽  
Caspian Sea ◽  
Water Area ◽  
Tsunami Hazard ◽  
Estimation Of Parameters ◽  
The Caspian Sea ◽  
Tsunami Waves ◽  
The North ◽  
Tsunami Hazard Assessment ◽  
Run Up

The article describes the tsunami hazard assessment for the coast of the Caspian Sea, in particular for the Absheron Peninsula. Due to the high socio-economic load on the coast of this region by electric power and oil production industries requirements, it is necessary to take into account risks even for such extremely rare natural phenomena like tsunamis. An earthquake with M = 8 ± 0.2 can occur throughout the Caspian Sea region, including land, once every 216 years, while for the water area the frequency of occurrence of such an event is 1620 years. The article presents the results of a tsunami hazard assessment based on a deterministic approach for the Absheron Peninsula. This approach of the tsunami hazard assessing of an arbitrary part of the coast consists of selecting of the strongest observed (or hypothetical) tsunami event from a neighborhood and from a distant zone, of the subsequent estimation of parameters for model sources and, finally, of the numerical modeling of tsunami generation and propagation from these sources. It was obtained that with the propagation of tsunami waves from the north to the coast of the Absheron Peninsula, its height can reach 3‒4 m for some parts of the coast with run-up 500‒1500 m.

scholarly journals INTERSPECIFIC NUTRITIONAL RELATIONSHIP BETWEEN CLUPEONELLA ENGRAULIFORMIS AND CLUPEONELLA CASPIA IN THE CASPIAN SEA

2019 ◽  
pp. 13-19
Author(s):  
Anna Viktorovna Mikhajlova
Keyword(s):  
Fish Species ◽  
Caspian Sea ◽  
Food Preferences ◽  
Pelagic Fish ◽  
Middle Part ◽  
Aqueous Environment ◽  
The Caspian Sea ◽  
Commercial Fish ◽  
The North ◽  
Close Relationship

Vital activity of the Caspian ichthyofauna is mainly determined by aqueous environment with its multiple factors influencing the hydrobionts’ life cycle. It is well known that in the process of evaluating the stocks of commercial fish species it is necessary to take into account supplying them with food. Trophologic studies of mature species of Clupeonella Caspia and Clupeonella Engrauliformis in the Caspian Sea make a basis for a large number of works; however, the research of food preferences of these fish species is scarce. Clupeonella Caspia inhabits the north, middle and south parts of the Caspian Sea above the 60 m isobath. Clupeonella Engrauliformis is widespread in the middle and southern parts of the Caspian Sea above the depths more than 200 m. In the course of evaluating kilka fattening in the Caspian Sea that was continued in 2011 there were estimated nutrition relations of kilka species over the many years, traced the degree of nutritional similarity and registered interspecific relationship between these pelagic fish. The results obtained have been summarized and the whole range of trophic studies has been shown. The monitoring nature of the studies allows to infer the intensive feeding of Clupeonella Caspia and Clupeonella Engrauliformis in the summer of 2011-2014 and in 2016 in the middle part of the Caspian Sea (the study of pelagic fish fatting was not conducted in 2015). The multi-year comparative analysis of Clupeonella Caspia and Clupeonella Engrauliformis nutrition demonstrated the differences of using the dominant foodstuff among planktonic invertebrates. It has been stated that the index of similarity of the food spectrum does not always have a greater degree of coincidence in close relationship of fish in a systematic respect.

scholarly journals DYNAMICS OF ZOOBENTHOS DEVELOPMENT WITHIN THE WATER AREA OF THE YURI KORCHAGIN FIELD IN THE NORT PART OF THE CASPIAN SEA

2018 ◽  
pp. 89-97
Author(s):  
Semen Nikolaevich Studnikov ◽  
Lyubov Vasilievna Malinovskaya ◽  
Alexey Vladimirovich Kuzin
Keyword(s):  
Population Density ◽  
Benthic Invertebrates ◽  
Caspian Sea ◽  
Water Area ◽  
The Caspian Sea ◽  
Survey Period ◽  
Gas Field ◽  
Field Development ◽  
The North ◽  
North Part

One of the main purposes of the monitoring studies is a long-term research of benthic communities of the north part of the Caspian Sea. Analysis of quantitative and qualitative characteristics is the only means to formulate main laws of the development of benthic biocenosis in terms of enhanced oil and gas field development, as well as to provide a forecast of the state of the fields and of the human impact on them. In the survey period, from 2014 to 2016, 43 species of benthic invertebrates, namely 2 species of Annelida, 32 species of Crustacea and 9 species of Mollusca, were identified as the result of zoobenthos development study. In that period, total average population density of the benthic fauna within the Yuri Korchagin field water area made 6 716 organisms per square meter, while the general average biomass constituted 77.324 grams per square meter. During the whole period of the research such zoobenthos species as Crustaceans and mainly Gammarids, including Ch. Ischnus and St. similis , dominated in terms of population density. As to biomass, the most abundant zoobenthos species were molluscs - Mediterranean species M. lineatus and A. ovata with D. protracta - a marine species - dominating in different years. Zoobenthos diversity, quantity fluctuations and dominance of given species in biomass and population density at certain stations of the studied water area were linked principally to the water salinity, type of soil and food resources availability. The study of benthic invertebrates showed that Yuri Korchagin field area in the north part of the Caspian Sea is characterized by a high development of euryhaline and marine benthic invertebrates.

scholarly journals QUANTITY AND DISTRIBUTION OF CASPIAN ROACH, BREAM AND PIKE PERCH UNDERYEARLINGS IN THE NORTH-WEST OF THE CASPIAN SEA IN CONDITIONS OF THE VOLGA HIGH WATER AND LOW WATER RUN OFF

2018 ◽  
pp. 74-82
Author(s):  
Ljubov’ Aleksandrovna Belogolova ◽  
Tatyana Anatolievna Solokhina
Keyword(s):  
Caspian Sea ◽  
High Water ◽  
Water Area ◽  
The Caspian Sea ◽  
Volga River ◽  
North West ◽  
The North ◽  
Run Off ◽  
Pike Perch ◽  
Caspian Roach

The article presents the comparative analysis of quantity and the distribution of Caspian roach, bream and pike perch underyearlings in western part of the northern Caspian in the current context of the Volga river high water and low-water run-off in 2013-2016. It has been shown that, depending on conditions of each year, the quantity of the three species underyearlings varies too much. The biggest number of Caspian roach and bream in the period under review was observed in 2013 and 2016, and the biggest pike perch quantity - in 2016. In spite of certain variability, the quantity of Caspian roach and pike perch underyearlings stays low today. Bream quantity in some years increased up to the level of middle yielding generations. In spite of low quantity, Caspian roach underyearlings almost completely developed feeding territories of western part of the north Caspian in both high water and in low-water years. The foraging area of bream and especially of pike perch underyearlings is smaller than Caspian roach one. They spread to the maximum upon the water area of the Caspian Sea in 2016, that year was the most favorable in salinity for generative freshwater fish for the last few years. Caspian roach underyearlings generally gained weight in waters with salinity over 8‰, bream - in desalinated areas with salinity up to 5‰. Pike perch underyearlings stayed in desalinated areas during the high water years; they were found across the studied spectrum with low (0-5‰), high (>10‰) and moderate water salinity (5-8‰) during the low-water years.

scholarly journals BIODIVERSITY OF OBJECTS OF AQUATIC BIORESOURCES OF THE VOLGA-CASPIAN FISHERY AREA

2017 ◽  
pp. 49-60
Author(s):  
Arsen Vyacheslavovich Mirzoyan ◽  
Raisa Pavlovna Khodorevskaya
Keyword(s):  
Caspian Sea ◽  
Sea Water ◽  
Natural Populations ◽  
Water Area ◽  
Commercial Fishing ◽  
Ecological Groups ◽  
The Caspian Sea ◽  
Sea Level Fluctuations ◽  
The North ◽  
Caspian Seal

In the course of the study there has been carried out the analysis of the data (both first-hand research and literature data), which characterize different species of fish, Caspian seal, river and crayfish and lobsters of the Volga-Caspian fishery basin. There have been listed families and species composition of the water biological resources on the water area of the Volga-Caspian fishery basin - 125 species and subspecies of fish (only 35 species are used in commercial fishing), belonging to 21 families. They have been divided into ecological groups according to spawning zones, preferred habitats and types of nutrition. Main features of ecological changes happened in the Caspian Sea for the last 65-70 years and resulted in drastic drop of fish catch volumes including sturgeons have been considered. In the populations of all sturgeon species there is a marked trend to dominating the young fishes - up to 80%. Increase in the number and improved biological characteristics was registered only in anadromous herring ( Alosa kessleri kessleri ) sires. Caspian seal retains the number of population on the level of the average annual figures, which is related to the favorable conditions for fattening and absence of critical epizootic situations. Materials on the long-term changes in the level of the Caspian Sea have been analyzed. The correspondence of sea level fluctuations and the size of commercial catches has been studied. The recommended measures for maintaining and development of the fishery complex in the Russian area of the Caspian basin (the Russian region) have been listed. The preservation of natural populations of all fish species, especially sea fish, anadromous fish of the Caspian Sea seems to be possible only if there are coordinated actions of all littoral states for preventing sea water pollution in the process of exploration and extraction of raw hydrocarbons, providing international inspections over preventive measures and creating the preserve zone in the North of the Caspian Sea (Russia, Kazakhstan).

ICE CONDITIONS IN THE NORTH-WESTERN PART OF THE CASPIAN SEA IN THE MODERN PERIOD

2020 ◽  
Vol 19 (6) ◽  
pp. 4-17
Author(s):  
Nepomenko Leonid ◽  
◽  
Popova Natalia ◽  
Zubanov Stepan ◽  
Ostrovskaya Elena ◽  
...  
Keyword(s):  
Caspian Sea ◽  
The Caspian Sea ◽  
The North ◽  
Modern Period ◽  
Ice Conditions ◽  
North Western
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