Migratory history of the Russian sturgeon Acipenser guldenstadti in the Caspian Sea, as revealed by pectoral fin spine Sr:Ca ratios

2002 ◽  
Vol 141 (2) ◽  
pp. 315-319 ◽  
Author(s):  
Arai T. ◽  
Levin A. ◽  
Boltunov A. ◽  
Miyazaki N.
Author(s):  
Takaomi Arai ◽  
Nobuyuki Miyazaki

Ontogenic change patterns in otolith Sr:Ca ratios were examined in the Russian sturgeon, Acipenser guldenstadti in the Caspian Sea. Otolith Sr:Ca ratios fluctuated widely during the life history in accordance with the migration pattern from freshwater to brackish water habitats, i.e. all specimens exhibited a typical anadromous pattern in the ratio. Several specimens had two transition points in otolith Sr:Ca ratios from the low ratios to the high indicating that those specimens had a flexible migration strategy in the ambient water and had the possibility of migrating downstream to the Caspian Sea multiple times after spawning in a freshwater habitat.


Author(s):  
Ardak Kapyshev

At  the  present  stage  one  of  the  unsolved   problems in  interstate relations of  Caspian bordering countries is defining international­legal status of the Caspian Sea. It is noted in the article that this problem is not a new one at all. The history of “division” of the Caspian Sea begins in the ancient age, namely in VIII century. It is underlined that the basic stumbling block  is the position of Iran on the right to use the Caspian Sea, and also occurrence of extra regional players, such as  the USA, China, etc. First of  all, it is connected with rich oil fields and other minerals, and also with convenient geopolitical and geostrategic position. The only way to worry out the international­legal delimitation of the Caspian Sea problem is a negotiating process. By now, despite of  certain disagreements on  legal status of  the Caspian Sea, five Caspian bordering countries managed to achieve certain progress, admitting the possibility of applying the principle of sectorial sectioning on the Caspian Sea.  Clear proof  of  it is the agreements on  division of ground on the northern part of Caspian Sea signed between Kazakhstan, Russia and Azerbaijan. It is important that Kazakhstan, Russia, Azerbaijan and Turkmenistan clearly stated their positions and agreed to make a compromise in their official statements. More than likely, in the near future Iran will soften its position, considering its present  situation and   strained relations with the USA. It has been alleged that the constructive  dialog  already  started; everything depends on  the mobility,  concurrency and rationality of actions of all Caspian bordering countries.


2020 ◽  
Vol 35 (2) ◽  
pp. 232-263
Author(s):  
Elena Karataeva

Abstract This article analyses new developments in the question of the Caspian Sea legal status, namely the signing of the Convention on the Legal Status of the Caspian Sea on 12 August 2018 in Kazakhstan, after twenty-six years in the making. First, the article provides an overview of the history of the Caspian Sea ownership and examines the legal status question from the collapse of the USSR to the present day. Then, the text of the newly signed Convention is examined to determine whether it provides the final answers to the issues of the legal status and delimitation of the sea. It is contended that despite this seminal breakthrough, the convention does not provide a complete solution. Specifically, while it establishes Caspian Sea zones and their limits, it fails to clarify some key contentious aspects, including delimitation principles between the opposite and adjacent Caspian States, which remain to be determined bilaterally.


2019 ◽  
Vol 10 (7) ◽  
pp. 2133
Author(s):  
Akmaral U. TYULYUBAYEVA ◽  
Madina M. ABISHEVA ◽  
Aikerim A. TURUNTAYEVA ◽  
Saltanat T. JAKUBAYEVA

Kazakhstan and the Islamic Republic of Iran are two states that have common sea borders through the Caspian Sea, two friendly neighbors, successfully developing both bilateral cooperation and cooperation at the regional and international level. The relevance of this study is that today it is advisable to study the foreign policy of not only world powers, but also ‘non-knowing’ countries in order to determine the scenario for the development of relations between the two countries. The purpose of the article is to analyze and evaluate the geostrategic features of the interaction of Kazakhstan and Iran in the regional and global aspects. The leading approach to the study of this problem is the analysis method, which allowed to study the history of relations between Kazakhstan and Iran at different stages. This article attempts to determine the geostrategic features of the interaction between Kazakhstan and Iran in the regional and world aspect analyze and evaluate their bilateral relations.  


2019 ◽  
Vol 20 (3) ◽  
pp. 326-338
Author(s):  
S.V. Shipulin ◽  
◽  
S.V. Kanat’ev ◽  
I.N. Lepilina ◽  
E’.Ju. Tikhonova ◽  
...  

Author(s):  
Irina Victorovna Konopleva

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.


F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 2807
Author(s):  
Alexey A. Sergeev

Russian (Acipenser gueldenstaedtii), Persian (A. persicus) and Siberian (A. baerii) sturgeons are closely related ‘Ponto-Caspian’ species. Investigation of their population structure is an important problem, the solution of which determines measures for conservation of these species. According to previous studies, ‘baerii-like’ mitotypes were found in the Caspian Sea among 35% of Russian sturgeon specimens, but were not found in Persian sturgeons. This confirms genetic isolation of the Persian sturgeon from the Russian sturgeon in the Caspian Sea. However, in order to clarify the relationships of these species it is necessary to analyze nuclear DNA markers. The amplified fragment length polymorphism (method) allows estimating interpopulation and interspecific genetic distances using nuclear DNA markers. In the present study, four samples were compared: Persian sturgeons from the South Caspian Sea, Russian sturgeons from the Caspian Sea and the Sea of Azov, and Siberian sturgeons from the Ob’ River, which are close to these two species, but are also clearly morphologically and genetically distinct from them. For the AFLP method, eight pairs of selective primers were used. The analysis revealed that the Siberian sturgeon has formed a separate branch from the overall Persian-Russian sturgeons cluster, which was an expected result. In addition, the results showed that the Caspian Russian sturgeon is closer to the Persian sturgeon from the Caspian Sea than to the Russian Sturgeon from the Sea of Azov. The present DNA marker data confirm that despite the genetic isolation of the Persian sturgeon from the Russian sturgeon in the Caspian Sea, the Persian sturgeon is a young species.


F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 2807
Author(s):  
Alexey A. Sergeev

Russian ( Acipenser gueldenstaedtii), Persian ( A. persicus) and Siberian ( A. baerii) sturgeons are closely related ‘Ponto-Caspian’ species. Investigation of their population structure is an important problem, the solution of which determines measures for conservation of these species. According to previous studies, ‘baerii-like’ mitochondrial genotypes were found in the Caspian Sea among 35% of Russian sturgeon specimens, but were not found in Persian sturgeons. This confirms genetic isolation of the Persian sturgeon from the Russian sturgeon in the Caspian Sea. However, in order to clarify the relationships of these species it is necessary to analyze nuclear DNA markers. The amplified fragment length polymorphism (method) allows estimating interpopulation and interspecific genetic distances using nuclear DNA markers. In the present study, four samples were compared: Persian sturgeons from the South Caspian Sea, Russian sturgeons from the Caspian Sea and the Sea of Azov, and Siberian sturgeons from the Ob’ River, which are close to the latter two species, but are also clearly morphologically and genetically distinct from them. For the amplified fragment length polymorphism (AFLP) method, eight pairs of selective primers were used. The analysis revealed that the Siberian sturgeon has formed a separate branch from the overall Persian-Russian sturgeons cluster, which was an expected result. In addition, the results showed that the Caspian Russian sturgeon is closer to the Persian sturgeon from the Caspian Sea than to the Russian Sturgeon from the Sea of Azov. The present DNA marker data confirm that despite the genetic isolation of the Persian sturgeon from the Russian sturgeon in the Caspian Sea, the Persian sturgeon is a young species.


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