Lack of the Caspian Ecosystem Monitoring
‘The lack of the Caspian ecosystems monitoring does not allow us objectively to assess its state,‘ says Yuriy Y, Dgebuadze, Academician, Deputy Academician-Secretary of the Biological Sciences Department, a member of the Presidium, the Russian Academy of Sciences.
The Caspian Sea is a unique natural site with outstanding biodiversity. It is inhabited by over 100 endemic (found nowhere else) fish species (62% of the Caspian ichthyofauna), and is the richest body of water on Earth in terms of sturgeon species abundance. Such a high level of endemism is also observed in other groups of aquatic organisms. However, scientists have been concerned about the status of the Caspian Sea and the Volga basin for several years. Moreover, many problems are global and transboundary in nature, and their solution requires the efforts of diplomats, officials and even law enforcement officers.
On May 11, 2022, Moscow once again hosts the Caspian Dialogue International Assembly, a forum of representatives from the five Caspian and other interested states, in the preparation of which the Russian Academy of Sciences traditionally takes part. On the eve of the forum, Yuriy Y. Dgebuadze, Academician, Deputy Academician-Secretary of the Biological Sciences Division of the Russian Academy of Sciences, co-chairman of the Presidium of the Council “Science and Innovations of the Caspian”, talked about some issues that would be raised in the forum.
‘Now it is not always possible to judge what is happening with the biota of the Caspian on the basis of specific data. Previously, hydrobiological samples were constantly taken at the same points in the sea. Specialists assessed hydrochemical parameters, abundance and biomass of benthic (i.e., living at the bottom) organisms, plankton living in the water column and, finally, fish feeding on them. And only then it was possible to talk about the state of the Caspian ecosystem, assess how organisms grew and what their reproduction was, the level of pollution at certain points in the water area. Now the main problem is how to objectively assess the situation.’
Until the beginning of the 2000s, there was an extensive network of hydrobiological stations in the Caspian Sea and in the regions of the Volga basin, the monitoring data of which allowed scientists from the institutes of the Academy of Sciences of the USSR and later the Russian Academy of Sciences to form an objective picture of what was happening in the waters and on the shores of the largest land-locked salty reservoir on the planet. After 2013, systematic sampling in the Russian part of the Caspian Sea has not been practically carried out. Scientists in their forecasts, as well as government officials, when planning economic activities, have had to rely almost exclusively on expert assessments. ‘Now there is no such network, and the only institute in the region under the methodological guidance of the Academy – it is the Caspian Institute of Biological Resources of the Far Eastern Federal Research Center of the Russian Academy of Sciences in Makhachkala – does not have any research vessel. And the Caspian Sea and its basin are gigantic,’ says Yuriy Y. Dgebuadze.
Figure 1. The network of hydrobiological stations, which were previously observed by the Caspian Institute of Biological Resources of the Far Eastern Federal Research Center, the Russian Academy of Sciences:
The Caspian Sea and the Volga delta are habitats for species of national, regional and global value. For example, out of 26 species of sturgeon known to science, six ‘officially’ live in the Caspian: beluga, Russian and Persian sturgeons, stellate sturgeon, sterlet and ship sturgeon. But scientists say that it is more honest to talk about five – the last of them, Acipenser nudiventris, was extinct by the 21st century. In addition, the Volga Delta is a place of migration and nesting for a large number of birds, many of which are also rare and endangered. And of course, the Caspian seal is the only marine living in the Caspian Sea, inscribing into the Red Data Book of Russia.
At the same time, there are many threats to the biodiversity of the Caspian Sea. Still flourishing poaching, overfishing of bioresources (except for sturgeon, one of the species of the whitefish subfamily, the white salmon, turned out to be on the verge of extinction). Pollution by waste waters of cities standing on the Volga, extraction of mineral raw materials from long-developed oil fields in neighboring Caspian states. Chemicals used in oil production and untreated urban sewage severely harm both juveniles and the reproduction process of numerous species of birds and fish. Measures of artificial restoration have some effect: back in the 1950s and 60s, domestic ichthyologists developed the technology of artificial reproduction; this resource is now mainly used by herds of sturgeons.
Yuri Y. Dgebuadze, being Head of Laboratory of Ecology of Aquatic Communities and Invasions at A.N. Severtsov Institute of Ecology and Evolution, the Russian Academy of Sciences, focuses on another side effect of the active trade in raw materials – introduction of invasive species into the sea.
‘Due to the increase in transportation, including oil export, the Caspian Sea and the Volga basin have become objects of introduction of non-native species. For example, more than 30% of fish in the Volga basin are not native species, but introduced as a result of human activities: in the process of deliberate introduction or transportation with ballast water. There is a practice when, after unloading the liquid cargo, for the stability of the vessel, part of the empty tanks is filled with outboard water and, upon arrival at a new port, it is simply poured out – along with a mass of living organisms. The International Convention for the Control and Management of Ships’ Ballast Water and Sediments (Ballast Water Management Convention or BWM Convention) prohibits this, but the rules are not always followed.’
According to biologists, up to 7 thousand species of living organisms are transported daily with ballast water to a new ‘place of residence’ in the world. In the Volga-Caspian basin, 9 of the 100 most dangerous invasive species of Russia have now naturalized. The most striking example is the comb jelly mnemiopsis (Mnemiopsis leidyi), which lives in the western part of the Atlantic Ocean. It caused colossal damage to the ecosystems of not only the Caspian, but also the Black and Azov Seas. The biological invasion of this species into the Caspian took place in the late 1990s. Gradually, the comb jelly destroyed the food and larvae of local fish species, provoking catastrophic changes in the structure of the ecosystem. Commercial fish catches have also significantly decreased. So, for example, the fishery of common and anchovy kilka in some cases decreased by an order of magnitude or more. It should be noted that these species were part of the sturgeon food base.
In addition to anthropogenic factors, there are other more global ones affecting the well-being of the Caspian. ‘Firstly, these are fluctuations in water level due to changes in the flow rates of rivers flowing into the sea, the main of which is the Volga, the longest river in Europe. In 1978–95 there was a significant increase in the level of the Caspian Sea, and from 1996 to the present it has been decreasing. Secondly, a lot of processes takes place at the bottom of the Caspian Sea: underwater tectonic changes, gas generation, changes in the hydrochemical regime – that also has a significant impact on hydrobionts and often leads to their death,’ Yuriy notes.
All five Caspian states, representatives from which take part in the Caspian Dialogue International Assembly and the Save the Caspian Conference (Russia, Azerbaijan, Iran, Kazakhstan and Turkmenistan) are parties to the Convention on Biological Diversity (1992) and participants in the Framework Convention for the Protection of the Marine Environment of the Caspian Sea (2003). But the lack of a coordinated monitoring system for biodiversity and the state of the Caspian ecosystems remains an acute problem.
The Biological Sciences Department of the Russian Academy of Sciences annually comes up with initiatives to restore the network for monitoring biodiversity and the state of ecosystems not only in the Caspian Sea, but throughout Russia. In the Caspian Sea, in addition to the already mentioned Caspian Institute of Biological Resources of the Far Eastern Federal Research Center of the Russian Academy of Sciences, a relatively small amount of joint research is also carried out with institutes subordinate to the Federal Agency for Fishery. Samples for their own research are taken by the Southern Scientific Center of the Russian Academy of Sciences based in Rostov-on-Don. P.P. Shirshov Institute of Oceanology of RAS has its own branch and conducts observations mainly in the northwestern part of the Caspian Sea. A certain amount of data is collected by state reserves (there are two of them in the Russian part of the Caspian Sea – Astrakhanskiy and Dagestanskiy State Nature Reserves) and the remaining biological stations of universities and institutes. But all this is not enough to understand the objective picture of natural phenomena occurring in the unique sea.
‘Actually, only two institutes operate in the Volga basin, subordinate to the scientific and methodological leadership of the Russian Academy of Sciences. These are I.D. Papanin Institute of Biology of Inland Waters. in the upper reaches, in the village of Borok, near the Rybinsk reservoir. Its ships used to sail all over the Volga, but now there are no such opportunities. And the Institute of Ecology of the Volga Basin of the Russian Academy of Sciences in Tolyatti, which makes small assessments in the middle reaches of the river.’
Now Science and Innovations of the Caspian Council, an organizer of the Caspian Dialogue International Assembly, is engaged in drawing attention to the problems of the Caspian basin. The Scientific Council for Hydrobiology and Ichthyology at the Biological Sciences Department of the Russian Academy of Sciences is also directly involved in solving the problems of the Caspian Sea – information on the situation is regularly sent to the ministries and departments of the Russian Federation. Scientists, in particular, call for the restoration of the scientific fleet and the resumption of annual all-Caspian hydrobiological surveys (the last one was in 2006). This is also important for studying the stocks of commercial aquatic organisms, their migration and distribution over the sea.
An idea to create a nature protected area in the northern part of the Caspian on the border with Kazakhstan, and possibly together with this country, was put forward. Attention is drawn to the negative consequences of possible projects for the cultivation of cotton in the Astrakhan Region. And of course, an international inspection is needed to control work in the extraction of hydrocarbon raw materials, strengthen the protection of populations of valuable commercial fish species and control over invasive species.
The following organisms inhabit the Caspian Sea (number of species): phytoplankton – 449; diatoms – 163; macrophytes – 82, of which: green algae – 33, red algae – 24, brown algae – 13; microphytobenthos – 318; zooplankton – 315; ciliates – 135; zoobenthos – 248, of which: endemics species – 151 (61%), in the Ponto-Caspian – 214 (86%); fish (total with river fish) – 162, of which: endemic species – 100 (62%), marine species – 119, of which endemic species – 79 (66%), commercial species – 35.
Source: The Russian Academy of Sciences.
In the photograph: Yuriy Y. Dgebuadze.