scholarly journals THE CURRENT STATE OF THE KEFAL FAMILY (MUGILIDAE) IN THE COASTAL ZONE OF THE DAGHESTAN COAST OF THE CASPIAN SEA

2020 ◽  
pp. 12-15
Author(s):  
Evgeny Nikolaevich LOBACHEV ◽  
Nukhkadi Ibragimovich RABAZANOV ◽  
Ruslan Magomedovich BARKHALOV ◽  
Umshanat Dzhamaldinovna ZURKHAEVA ◽  
Diana Pavlovna KLUSOVA
Keyword(s):  
Coastal Zone ◽  
Marine Fish ◽  
Caspian Sea ◽  
Environmental Changes ◽  
Anthropogenic Factors ◽  
Main Role ◽  
The Caspian Sea ◽  
Freshwater Bodies ◽  
Fish Catch ◽  
Quantitative Changes

For more than a century of active commercial exploitation and environmental changes in the Caspian Sea, the structure of the population of marine fish species has undergone significant qualitative and quantitative changes. In this group of fish until 1960, the main role in the fishery was played by sea herring, which provided up to 50–70% of the total fish catch in the region. Interest in the study of marine fish of the Caspian Sea, using the example of mullets, Black Sea acclimatizers, is due to the fact that under new conditions, as well as a result of deep negative changes in the ecology of this reservoir under the influence of natural and anthropogenic factors, especially recently. At present, among marine fish, one of the main and promising fishing objects is mullet, which, since the period of acclimatization, has formed a high abundance in the coastal zone of the Daghestan coast of the Caspian Sea. Mullet are euryhaline fish that can live both in sea, salty water, and freshwater bodies. In this regard, the objects of this study were mullet (singil), the study of their commercial catches and stocks in the Caspian Sea.

Spatio-temporal variability of internal waves in the Caspian Sea

2020 ◽  
Author(s):  
Olga Lavrova ◽  
Andrey Kostianoy
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Internal Waves ◽  
Satellite Data ◽  
Caspian Sea ◽  
Bottom Topography ◽  
Sea Surface ◽  
Anthropogenic Factors ◽  
Landsat 8 ◽  
The Caspian Sea

<p>Internal waves (IWs) are an intrinsic feature of all density stratified water bodies: oceans, seas, lakes and reservoirs. IWs occur due to various causes. Among them are tides and inertial motions, variations in atmospheric pressure and wind, underwater earthquakes, water flows over bottom topography, anthropogenic factors, etc. In coastal areas of oceans and tidal seas,  IWs induced by tidal currents over shelf edge predominate. Such IWs are well-studied in multiple field, laboratory and numerical experiments. However, the data on IWs in non-tidal seas, such as the Black, Baltic and Caspian Seas, are scarce. Meanwhile, our multi-year satellite observations prove IWs to be quite a characteristic hydrophysical phenomenon of the Caspian Sea. The sea is considered non-tidal because tide height does not exceed 12 cm at the coastline. And yet surface manifestations of IWs are regularly observed in satellite data, both radar and visible. The goal of our study was to reveal spatial, seasonal and interannual variability of IW surface manifestations in the Caspian Sea in the periods of 1999-2012 and 2018-2019 from the analysis of satellite data. All available satellite radar and visible data were used, that is data from ERS1/2 SAR; Envisat ASAR; Sentinel-1A,1B SAR-C; Landsat-4,5 TM; Landsat-7 ETM+; Landsat-8 OLI; Sentinel-2A,2B MSI sensors. During the year, IWs were observed from the beginning of May to mid-September. In certain years, depending on hydrometeorological conditions, such as water heating, wind field, etc., no IWs could be seen in May or September. IWs regularly occur in the east of Middle Caspian and in the northeast of South Caspian. In North Caspian, due to its shallowness and absence of pronounced stratification, IWs are not generated, at least their surface signatures cannot be found in satellite data. In the west of the sea, IWs are scarcely observed, primarily at the beginning of the summer season. IW trains propagate toward the coast, their generation sites are mainly over the depths of 50-200 m.</p><p>According to the available data for the studied periods, the time of the first appearance of IW signatures differs significantly from year to year. For example, in 1999 and 2000 it happened only in July.</p><p>Since no in situ measurements were conducted in the sites of regular IW manifestations, an attempt  was made to establish the dependence of IW occurrence frequency  on seasonal and interannual variations of sea surface temperature, an indirect indicator of the depth of the diurnal or seasonal thermocline, that is where IW were generated. Sea surface temperature was also estimated from satellite data.</p><p>Another issue addressed in the work was the differentiation between the sea surface signatures of IWs in the atmosphere and the sea. The Caspian Sea is known for their close similarity in spatial characteristics.</p><p>The work was carried out with financial support of the Russian Science Foundation grant #19-77-20060.  Processing of satellite data was carried out by Center for Collective Use “IKI-Monitoring” with the use of “See The Sea” system, that was implemented in frame of Theme “Monitoring”, State register No. 01.20.0.2.00164.</p>

scholarly journals Fluctuation in the Level of the Caspian Sea and its Consequences

2021 ◽  
Vol 288 ◽  
pp. 01064
Author(s):  
Akimgali Kenzhegaliev ◽  
Assylbek Kanbetov ◽  
Dauren Kulbatyrov ◽  
Aiauzhan Shakhmanova ◽  
Ainagul Abilgaziyeva
Keyword(s):  
Sea Level ◽  
Caspian Sea ◽  
Climatic Factors ◽  
Anthropogenic Factors ◽  
Present Stage ◽  
The Caspian Sea ◽  
Industrial Facilities ◽  
Sea Levels ◽  
Early Neogene ◽  
Rising Sea Levels

While in the early neogene, tectonic and to a lesser extent climatic factors impacted on the sea level, at the present stage climatic, man-made and anthropogenic factors are at the forefront. As a result of an increase in the level of the Caspian Sea by more than 2.4 m, 35-40 thousand square meters km of territory was flooded, during the flooding and flooding of the coastal territory for the period 1978-1995 led to a change in natural, socio-economic and medico-ecological conditions. The consequences of rising sea levels led to the resettlement of about 100 thousand people living in the coastal flooded zone of the Northern Caspian Sea and many industrial facilities.

scholarly journals ASSESSMENT OF INFLUENCE OF THE AUTOACCLIMATIZERS ON AUTOCHTHONOUS BIVALVE MOLLUSKS

2020 ◽  
pp. 6-11
Author(s):  
Marina Vladimirovna KHLOPKOVA ◽  
Ruslan Magomedovich BARKHALOV ◽  
Kais Magomedovich GUSEYNOV ◽  
Aysha Sharapatinovna GASANOVA
Keyword(s):  
Caspian Sea ◽  
Main Role ◽  
Bivalve Mollusks ◽  
The Caspian Sea ◽  
Anthropogenic Transformation ◽  
European Part Of Russia ◽  
Russian Sector ◽  
Mytilaster Lineatus ◽  
A New Species ◽  
Benthivorous Fishes

Anthropogenic transformation of the Caspian Sea biocenoses results in the loss of their uniqueness and decrease of their biodiversity. In recent years the main role in the formation of biomass has played the autoacclimatizant mollusks Abra ovata , Mytilaster lineatus and Cerastoderma glaucum which dominate the biocenoses of the Caspian sea and are the main food components of valuable commercial benthivorous fishes. In 2018 live specimens of Corbicula fluminalis (O. F. Muller, 1774), a new species of bivalve mollusks for the Russian sector of the Caspian sea and the entire European part of Russia, were first discovered on the Daghestan coast.

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 Diversity, morphology and karyotypes of species from genus Neogobius (Perciformes; Gobiidae) at coastal zone of the Caspian Sea (Aktau city)

2017 ◽  
Vol 10 (1) ◽  
pp. 4-8
Author(s):  
A.B. Bigaliev ◽  
◽  
S.S. Kobegenova ◽  
K.B. Adyrbekova ◽  
S.A. Gutsulyak ◽  
...  
Keyword(s):  
Coastal Zone ◽  
Caspian Sea ◽  
The Caspian Sea

scholarly journals Population dynamics and the risk of stock extinction of Persian sturgeon (Acipenser persicus Borodin) in the Caspian Sea

2020 ◽  
Vol 28 (2) ◽  
pp. 62-72
Author(s):  
Hasan Fazli ◽  
Mahmoud Tavakoli ◽  
Mohammad Reza Khoshghalb ◽  
Mehdi Moghim ◽  
Tooraj Valinasab
Keyword(s):  
Caspian Sea ◽  
Population Biology ◽  
Significant Proportion ◽  
Anthropogenic Factors ◽  
Total Biomass ◽  
South Caspian Basin ◽  
The Caspian Sea ◽  
Persian Sturgeon ◽  
Acipenser Persicus ◽  
The Impact

AbstractPersian sturgeon, Acipenser persicus Borodin, has been the most significant proportion of Iranian commercial sturgeon catches in the Caspian Sea over in the last three decades. This endemic species has suffered continuous population declines from the impact of anthropogenic factors. The present study filled in information gaps on underlying population biology parameters, evaluated the population status, and determined the vulnerability risk of the stock extinction of Persian sturgeon in the south Caspian basin of Iran. Growth parameters were L∞ = 224.7 cm, K = 0.058 years−1, t0 = -3.4 years. Sexual maturity of 50% for males and females was FL = 127.2 cm and 137.5 cm, respectively. The long-term age composition data showed 35 age groups, and the ages of 14–18 years comprised 80% of the total catch. Natural mortality was 0.123 years−1, and fishing mortality ranged between 0.104 and 0.331 years −1. The total biomass trend decreased and collapsed from 6,071.3 tons in 1990–91 to 144.1 tons in 2014–15. Although >93% of the catch included maturing specimens, the Persian sturgeon stock is now critically endangered because of several anthropogenic factors.

scholarly journals Free-living ciliates in different coastal zone biotopes at the Azerbaijan sector of the Caspian Sea

Protistology ◽  
2019 ◽  
Vol 12 (3) ◽  
Author(s):  
Ilham Kh. Alekperov ◽  
◽  
Elyana N. Tahirova ◽  
Keyword(s):  
Coastal Zone ◽  
Caspian Sea ◽  
The Caspian Sea ◽  
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