scholarly journals History and status of sturgeon stock (Acipenseridae) in the Caspian pool

Vestnik MGTU ◽  
2020 ◽  
Vol 23 (2) ◽  
pp. 105-114
Author(s):  
A. D. Vlasenko ◽  
T. I. Bulgakova ◽  
I. N. Lepilina ◽  
I. V. Konopleva ◽  
I. A. Safaraliev
Keyword(s):  
River Flow ◽  
Agricultural Runoff ◽  
Anthropogenic Factors ◽  
Volga River ◽  
Rational Use ◽  
Ecological Adaptability ◽  
The North ◽  
Current State ◽  
Natural Reproduction

Analysis of materials from long-term studies characterizing the current state of sturgeon stocks in the Volga-Caspian fisheries basin, and the dynamics of commercial catches of beluga, sturgeon and stellate sturgeon in the XX - XXI centuries indicates that the Northern Caspian occupies the leading value in catch volumes, where more than 70 % of sturgeon fish are annually harvested. In the first half of the twentieth century sturgeon stocks were determined by the scale of natural reproduction in rivers and fishing volumes; in the second half, natural and anthropogenic factors began to intensively influence the formation of sturgeon stocks. The development of hydraulic construction on rivers, an increase in the withdrawal of freshwater runoff, a decrease in sea level to -29.0 mBS, pollution by industrial and agricultural runoff have necessitated the development of a set of measures for the reproduction, conservation and rational use of the Caspian’s aquatic biological resources. As a result of the studies, the response of the sturgeons to the changed conditions of reproduction has been determined in order to restore and increase their commercial stocks; high ecological adaptability of sturgeons to various living conditions within their range, their exceptional plasticity and pronounced intraspecific differentiation have been established. These indicators point to the possibility of creating conditions that meet the requirements for water quality for the life of sturgeons during migration and reproduction. In the course of the analysis of the obtained data, the influence of regulation of the Volga River flow on the efficiency of natural reproduction of sturgeons has been evaluated; the role of industrial sturgeon breeding in sturgeon stock formation has been shown; the abundance of juveniles in the North Caspian and adult individuals on feeding pastures of the sea has been estimated; trends in the number of sturgeon producers migrating in the Volga to spawning sites have been identified; the prospects for the restoration and rational use of sturgeons in the Volga-Caspian basin have been determined.

CURRENT STATE AND DEVELOPMENT PERSPECTIVES OF THE CASPIAN SPRAT FISHERIES

2018 ◽  
pp. 69-75
Author(s):  
Tatiana Vasilievna Pomogaeva ◽  
Aliya Ahmetovna Aseinova ◽  
Yuriy Aleksandrovich Paritskiy ◽  
Vjacheslav Petrovich Razinkov
Keyword(s):  
Food Item ◽  
Growth Potential ◽  
North West ◽  
Marine Fishery ◽  
The North ◽  
Current State ◽  
West Part ◽  
Eggs And Larvae ◽  
Intensive Growth

The article presents annual statistical data of the Caspian Research Institute of Fishery. There has been kept track of the long term dynamics of the stocks of three species of Caspian sprat (anchovy, big-eyed kilka, sprat) and investigated a process of substituting a food item of sprats Eurytemora grimmi to a small-celled copepod species Acartia tonsa Dana. According to the research results, there has been determined growth potential of stocks of each species. Ctenophoran-Mnemiopsis has an adverse effect on sprat population by eating fish eggs and larvae. Ctenophoram - Mnemiopsis is a nutritional competitor to the full-grown fishes. The article gives recommendations on reclamation of stocks of the most perspective species - common sprat, whose biological characteristics helped not to suffer during Ctenophoram outburst and to increase its population during change of the main food item. Hydroacoustic survey data prove the intensive growth of common sprat biomass in the north-west part of the Middle Caspian. According to the results of the research it may be concluded that to realize the volumes of recommended sprat catch it is necessary to organize the marine fishery of common sprat at the Russian Middle Caspian shelf.

scholarly journals Current state of bacterioplankton in Northern Caspian

2021 ◽  
Vol 0 (4) ◽  
pp. 31-38
Author(s):  
Svetlana Aleksandrovna Dyakova ◽  
Olga Borisovna Soprunova ◽  
Ecatherina Rafaelevna Galyautdinova ◽  
Anna Vitalievna Menkova ◽  
Dinara Gaidarovna Baubekova ◽  
...  
Keyword(s):  
Annual Runoff ◽  
Total Abundance ◽  
The North ◽  
Current State ◽  
Maximum Value ◽  
Simultaneous Decrease ◽  
Positive Correlations ◽  
Research Period ◽  
Number Of Bacteria

Microbiological monitoring of the Northern Caspian proved that for the research period in 2013-2018 the average annual value of the total number of bacteria (TBN) was 1.35 million cells/ml. The TBN maximum value (1.46 million cells/ml) was recorded in 2013, the minimum (1.19 million cells/ml) - in 2014. Concentration of saprotrophic bacteria in the waters of the Northern Caspian during the research period varied from 50.94 thousand CFU/ml in 2013 to 1.66 thousand CFU/ml in 2014. The concentration of saprotrophic bacteria remained practically unchanged within 2014-2018. The values of the ratio of the total abundance of microorganisms and saprotrophic bacteria show the eutrophication of the waters of the North Caspian in 2013 and in 2016, in other periods the water quality corresponded to the readings of an oligotrophic reservoir. The maximum number of oil-oxidizing bacteria (OOB) (8.28 thousand CFU/ml) in the waters of the Northern Caspian was recorded in 2013, the minimum (0.21 thousand CFU/ml) - in 2014. Starting from 2015 there was recorded an increasing number of OOBs and its stabilization until the end of the research period. The ratio of NOB and saprotrophs in water varied from 16.47 to 52.47%. Analysis of microbiological and hydrological-hydrochemical indicators revealed positive correlations of TBN and annual runoff (r = + 0.77), TBN and the content of mineral forms of nitrogen (r = + 0.60), the number of saprotrophic bacteria and nitrogen (r = + 0.83), the amount of NOB and mineral nitrogen and silicon (r = + 0.81). In the long-term aspect, an improvement in the microbiological situation was recorded against the background of a growing total number of bacterioplankton under a simultaneous decrease in the number of saprotrophic and oil-oxidizing bacteria.

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 STATE OF FISHERIES IN SOUTH REGION OF VOLGO-CASPIAN FISHERIES BASIN

2021 ◽  
Vol 2021 (3) ◽  
pp. 7-17
Author(s):  
Pavel Aleksandrovich Balykin ◽  
Raisa Pavlovna Khodorevskaya
Keyword(s):  
Annual Runoff ◽  
Southern Region ◽  
The Caspian Sea ◽  
Volga River ◽  
Total Allowable Catch ◽  
Fish Resources ◽  
The North ◽  
Current State ◽  
Pike Perch ◽  
North Western

The paper presents the generalized materials on the current state of fisheries in the Northern part of the Caspian Sea (southern region of the Volga-Caspian fisheries basin). It is shown that catches in the North-Western and Tersk-Caspian subdistricts varied in the opposite way: an increase in production in one subdistrict was accompanied by a decrease in the other. The decreasing or increasing catches is due to semi-anadromous (roach, brim, zander, carp) and freshwaterfish species (cat-fish, pike-perch, small size ordinary fish). There have been found the significant relationships between the size of catches in the North-Western and Tersk-Caspian subdistricts with the annual runoff and the volume of spring flooding of the Volga river, which allows to conclude that fish resources are redistributed between these regions depending on the natural conditions of a particular year. In order to more fully develop the fish resources of the southern region of the Volga-Caspian fisheries basin, it is recommended to abandon the division of quotas into parts for the North-Western and Tersk-Caspian subdistricts and to allow the fishing organizations to work at the expense of the total allowable catch

scholarly journals Children's Perception of Wolverine in the North Slave Region of the Northwest Territories, Canada

ARCTIC ◽  
2019 ◽  
Vol 72 (3) ◽  
pp. 229-244
Author(s):  
Morgane Bonamy ◽  
Andrew B. Harbicht ◽  
Thora Martina Herrmann
Keyword(s):  
Rural Communities ◽  
Northwest Territories ◽  
Capital City ◽  
Public Outreach ◽  
Outreach Programs ◽  
The North ◽  
Current State ◽  
Level Of Knowledge ◽  
Areas Of Concern

The public’s level of knowledge and opinions towards certain species can greatly impact their willingness to support present or future conservation or management programs. When public opinion is mixed, as is often the case with wild carnivores, an accurate assessment of perceptions and knowledge can identify areas of concern and help guide public outreach efforts. When such outreach programs focus on children they can be particularly effective for two reasons: 1) the opinions of children towards wild animals are often more flexible than the ingrained beliefs of adults, and 2) it is the younger generation that will be called upon to support long-term conservation efforts in the future. To assess the degree of knowledge and the current state of opinion among children towards a little known and often negatively perceived Arctic species, the wolverine (Gulo gulo), we conducted surveys with school children between the ages of 8 – 12 years old in seven schools within the North Slave Region of the Northwest Territories. Results from 151 completed surveys confirm that the majority of children lack general knowledge about this species, though the overall level of knowledge was higher in small, rural communities than the larger capital city of Yellowknife. Negative values were among the most commonly expressed values we observed, but so too was an appreciation for the ecological role that wolverines play in nature. The results of this study can be used to implement new educational programs aimed at increasing the overall level of acceptance of the wolverine and similar carnivores, and to encourage the public’s willingness to support conservation efforts for this often negatively perceived species.

Role and policies of presidents in the union of the two Korean states

2020 ◽  
Vol 72 (4) ◽  
pp. 117-124
Author(s):  
A.M. Zhandossova ◽  
◽  
Sh.M. Zhandossova ◽  
М.М. Nurov ◽  
◽  
...  
Keyword(s):  
The South ◽  
Short Term ◽  
National Community ◽  
The North ◽  
Current State ◽  
History Of ◽  
Relationship Of ◽  
The Relationship

This article examines the relationship of the two Korean states to unification, as well as the policies and various programs of the presidents who ruled the country after the separation. The authors characterized inter-Korean relations as «a history of long-term conflicts and short-term cooperation». The history of post-party relations between the North and the South is also studied, the need for a national community, the current state of the integration environment and how the peaceful reunification of the two countries will take place.

scholarly journals Geochemistry of suspended matter in the Volga river marginal filter

2019 ◽  
Vol 59 (3) ◽  
pp. 421-432
Author(s):  
V. N. Lukashin ◽  
M. D. Kravchishina ◽  
A. A. Klyuvitkin ◽  
A. N. Novigatsky ◽  
N. V. Politova
Keyword(s):  
Particulate Matter ◽  
River Flow ◽  
Chemical Elements ◽  
Marginal Filter ◽  
Term Study ◽  
Volga River ◽  
Long Term Study ◽  
Suspended Particulate ◽  
Flow Changes

The first data on the long-term study of marginal filter (MF) of the Volga River is presented. The concentrations of suspended particulate matter, suspendforming chemical elements and microelements are considered. Ratios of enrichment suspension by chemical elements relative to the upper lithosphere are calculated. as well as their interrelations at different stages of the MF. It is shown that the sedimentary substance supplied by the sea with river flow, changes radically, both quantitatively and qualitatively.

scholarly journals Long-term dynamics and current state of yellowfin sole Limanda aspera stocks in the waters of Sakhalin Island

2014 ◽  
Vol 178 (3) ◽  
pp. 25-57
Author(s):  
Alexander O. Zolotov ◽  
Alexander V. Smirnov ◽  
Lev N. Baranchuk-Chervonny ◽  
Anna Yu. Dubinina
Keyword(s):  
Bering Sea ◽  
Sakhalin Island ◽  
Secondary Importance ◽  
The North ◽  
Current State ◽  
Large Populations ◽  
Yellowfin Sole ◽  
Limanda Aspera ◽  
The North Pacific

Commercial stocks of two yellowfin sole populations on the western and eastern shelves of Sakhalin Island are assessed by VPA method using the data on their size-age structure and fishery statistics for 1950-2013. Results of the assessment are compared with the data of bottom trawl surveys conducted in 2000-2013. The yellowfin sole at Sakhalin Island had two periods of high abundance: in the 1950-1960s and in the 1985-1995, but its stocks decreased in the 1970-1980 and after the middle 1990s. This dynamics is similar to the dynamics of other large populations of yellowfin sole in the North Pacific - in the southeastern and western Bering Sea and on the shelf of West Kamchatka. All these changes are caused by natural reasons; fishery has secondary importance and affects on the populations in times of low stock only.

scholarly journals Climatic and Anthropogenic Factors in Long-term Alterations of the Volga River Runoff

2013 ◽  
pp. 4-19
Author(s):  
Keyword(s):  
River Runoff ◽  
Statistical Data ◽  
Annual Runoff ◽  
Anthropogenic Factors ◽  
Volga River ◽  
Instrumental Observations ◽  
Runoff Changes ◽  
Seasonal Runoff ◽  
Natural Climate

The contribution of natural climate and anthropogenic factors in the Volga river runoff changes at Volgograd during the period of instrumental observations (1882–2007). has been revealed. The estimates are based on two independent approaches. One of them is based on the restoration of the annual and seasonal runoff against the riversindicators’ regression dependencies, and the other one is based on the water use statistical data and methods of water balance. The calculations give the total Volga river annual runoff anthropogenic decrease values that are fairly close to each other.

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