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Volume 7. Number 2

20-06-2024

Год / Year
2024

 




CONTENT

Volume 7 Number 2 2024


Environmental Concerns and the State of Aquatic Environment


Seasonal dynamics of the water chemical composition for the Irtysh River within the Omsk Region
Zharkova N.N., Bazhenova O.P., Gavrilchenko O.L., Boltovskaya A.S. 

Abstract

Background. The Irtysh is a large transboundary river flowing through the territory of three countries: China, Kazakhstan, and Russia. This river is crucial for the economic activity of  the  population  of  all these countries and is subjected to heavy anthropogenic pressure, including pollution by industrial wastewater and runoff from watersheds. Relevance. Monitoring of the Irtysh River water quality is an essential task, which importance is  driven  by  the  need  for  the  assessment of  its  environmental  status in the context of increased anthropogenic impact and global warming, as well as by the necessity for identification of common patterns in the changes of the water chemical composition of transboundary  rivers. The aim of this research is to study the seasonal dynamics of the chemical composition of the Irtysh River water within the territory of the Omsk Region. Methods. This work is based on the data obtained through hydrochemical analysis using the conventional methods; the samples were collected along the  entire stretch of the Irtysh River within the Omsk Region from May to October 2023. Results. Exceedance  of the average monthly values of maximum permissible concentrations (hereinafter referred  to as MPCs)  for the water bodies used for fisheries has been identified for several parameters: up to 1.5 times for suspended solids, up to 1.4 times for BOD ,  and up to 5.0 times for PO 3- (based on P). The average monthly concentrations of ammonium nitrogen, petroleum products and phenols did not exceed the prescribed values. Conclusion. The content of easily oxidizable organic matter (based on BOD5) and biogenic elements in the water of the Irtysh River within the Omsk Region has a pronounced seasonal variation; the highest values have been observed in spring and autumn, and the lowest values have been recorded during the summer low water period.

Keywords: hydrochemical parameters, seasonal dynamics, Irtysh River, Omsk Region


Biology and Ecology of Aquatic Organisms



Distribution and ecological features of the mollusс Hydrobia acuta (Draparnaud, 1805) off the coast of Crimea
Makarov M.V., Kopiy V.G. 

Abstract

Background. The distribution of the gastropod mollusc Hydrobia acuta in relation to seasons, temperature, depth, salinity and biotopes along the Crimean coast from Karkinit Bay to the  Cape  Kazantyp for the  period from 2001 to 2023 has been considered. This species is abundant and wide-spread in the Black and Azov Seas; however, there have been no papers dedicated to it specifically since 1976. Some biotopes, in particular the epiphyton of some Chlorophyta, have not been previously investigated. It contributes to the relevance of this work, which is aimed at providing the summary of the data on the ecology of H. acuta. Sampling was carried out according to the generally accepted benthic methods with special consideration  for the biotopes. According to the results, this mollusc was the most abundant (39,625 ind./m2) in the Crimean coastal area at  the mouth of  the Chernaya (Black) River on  loose substrates in August 2011,     and  its highest biomass (28.48 g/m2) was recorded in  the same area and  substrate in  September 2022.    On macrophytes, the highest abundance and biomass were recorded in the associations  of  algae  Cladophora sp.+Chaetomorpha sp. in the Kazantyp area in July 2009—23,333 ind./kg and 23.33 g/kg, respectively. The conclusion is that the mollusc H. acuta is distributed along the Crimean coast non-uniformly; it has been found to  prefer silty bottoms and thickets of green algae, shallow-water sites    at the heads of bays and in Karkinit Bay  itself  (sometimes with  increased  salinity), as  well  as  in  the river estuary (mostly with reduced salinity).

Keywords: species, abundance, biomass, biotope, distribution



On the matter of the assessment of the Antarctic krill Euphausia superba exploitable stocks in the Antarctic Peninsula area based on the trawl catch data from the commercial fishing vessels
Korzun Yu.V., Kukharev N.N., Zhuk N.N., Kriskevich L.V.

Abstract

Background.  The  assessment  of  the  density  and  total  biomass  of the  Antarctic  krill  aggregations has been conducted based on the commercial catches by the fishing and krill harvesting trawlers (supertrawlers) “Konstruktor  Koshkin”  (“Design  Engineer  Koshkin”)  in  2006  and  “More Sodruzhestva” (“Commonwealth Sea”) in 2017 in the Bransfield Strait (FAO Subarea 48.1). Relevance. Recommencement of the Russian krill  harvesting  necessitates timely strategical characterization of the krill aggregations with regard to their prospective exploitation. This work is  aimed  at  the  identification of the density and biomass of  the Antarctic krill  aggregations in  2006  and  2017,  which have been calculated by  the  volumetric (net)  method  based  on  the  catches by  the  commercial  vessels in the Bransfield Strait. Methods. A midwater rope trawl of the 74/600 m design with the mesh size 20 mm in the krill-targeting insertion was used as a fishing gear. Estimation of the biomass was done using the isoline method. The catchability coefficient was considered to be 1.  Mapping of  the  biomass  density values was conducted with Golden Software Surfer 9 and QGIS 2.18.16. Confidence intervals for the average variation were calculated with  95  %  probability.  Results. The  decrease in  the  average  density of  the krill biomass at the harvesting sites in  the Bransfield Strait in 2017 (18.0±0.23 g/m3) as compared    to 2006 (32.5±0.40 g/m3) has been identified; it resulted from the krill aggregations scattering over the increased area. The total krill biomass in the aggregations in 2006 and 2017 was 2678.3±65.07 thousand t and  2743.1±68.70  thousand  t,  respectively.  Conclusion.  Based  on  the   commercial  trawl  catches,   the volumetric method allows for the expedient estimation of the density and biomass of the krill aggregations with the size composition  optimal  for  their  exploitation.  Taking  into  consideration  that the commercial trawls capture the relatively large-sized krill preferred by  the krill-dependent predators,  the volumetric method makes it possible to estimate the volume of their food reserves. Exploitable krill stock in the aggregations in the Bransfield Strait in  2017  remained virtually unchanged as  compared to  that of 2006 and amounted to 2.7 million t.

Keywords: Antarctic krill, biomass, distribution, midwater rope trawl, aggregation density


Ichthyoplankton of coastal waters of the Southeastern Crimea during the summer spawning season of 2023
Petrova T.N. 

Abstract

Background. The last systematic studies of ichthyoplankton in the coastal waters of Southeastern Crimea were carried out  30  years ago.  However,  despite the  high importance of  this  aquatic area for  fish reproduction, the current data on it remain extremely scarce. Relevance. Monitoring surveys of ichthyoplankton carried out by the Karadag Biological Station make it possible  to  analyze  the  current state of ichthyoplankton complexes and predict the success of recruitment to the natural fish populations. The aim of this  article  is  to  analyze  the  data  obtained  during  monitoring  studies  of  ichthyoplankton in the coastal waters of Southeastern Crimea during the summer spawning season of 2023. Methods. Ichthyoplankton samples were collected in May–September 2023 in the coastal waters along the south- eastern part of  the Crimean Peninsula over a  depth of  3  to 20  m.  Fifteen expeditions were carried out      in the aquatic area of the Karadag Nature Reserve, in Tikhaya (Quiet) Bay and Lisya (Fox) Bay. Results. Eggs and larvae of 30  fish  species belonging to  20  families have  been  identified. The  average  number of eggs was 145.9 pcs./100 m3, and for larvae it was 15.1 ind./100 m3. Species similarity index for the summer ichthyoplankton in 2020 and 2023  was  0.79. Diversity indices in  2023 decreased by  an  average of 1.2 times compared to 2020 due to the pronounced dominance of anchovy, which had not been  previously observed. Conclusion. The highest number of species (28) was recorded in  the  coastal waters  of the Karadag Nature Reserve: the abundance of eggs was 153.2 pcs./100  m3,  and  the  abundance  of larvae was 12.0 ind./100 m3. The lowest number of species (14) was observed in Tikhaya (Quiet) Bay: the abundance of eggs was 113.0 pcs./100 m3, and the abundance of larvae was 7.7 ind./100 m3. In the samples, the eggs of Engraulis encrasicolus (52.0 %) and Mullus barbatus (20.6 %) prevailed. Among larvae, the most prevalent were those of  anchovy (46.4 %)  and  hatched from  demersal eggs of  Chromis chromis,     as well as the fish species belonging to the families Gobiidae, Blenniidae, and Labridae (40.2 %).

Keywords: ichthyoplankton, summer spawning season, species diversity, abundance, coastal waters, Karadag, Crimea, Black Sea


Ichthyofauna of Marine and Inland Water Bodies



Fluctuating asymmetry of the head seismosensory canals in belica Leucaspius delineatus (Heckel, 1943) from small ponds with different content of total dissolved solids and hardness cations
Kotegov B.G. 

Abstract

Background. The change in external conditions is accompanied by various  responses  of  organisms existing in an unstable and heterogeneous environment. Relevance. Under the influence of physico- chemical factors of the aquatic environment, the frequency and extent of asymmetric manifestations of bilateral morphological features in fish individuals may increase, which is a consequence of an  imbalance  in their development and reflects the level of environmental stress. The aim of  this work was to examine  the fluctuating asymmetry (FA) in the number of pores in the head seismosensory canals of belica Leucaspius delineatus (sunbleak) from the water bodies that differ in the content of total dissolved solids (water mineralization) and hardness cations. Methods. Ichthyological material  was  collected  in  nine  small ponds belonging to the Kama River basin in the Udmurt Republic in 2018–2019. In the captured individuals of belica, the number of pores in the seismosensory canals in four  paired head  dermal bones  has been identified, on the basis of which two FA indices have been calculated. Results. In several water bodies, a considerable proportion of belica mature individuals with incompletely ossified sections of the head seismosensory canals, often on one side only, or on the both sides but to different extents, has been recorded. This proportion determined the FA indices of the studied seismosensory features and had a  positive correlation with the content of magnesium ions in the water bodies. In the belica individuals with fully ossified  head seismosensory canals, the FA  variance of the total number of pores in these canals had  a positive correlation with the total dissolved solids in the water of  the investigated small ponds; however,  it  had  not  depended on  the content of hardness cations in them. Conclusion. The  possible mechanisms   of the influence of the investigated hydrochemical factors on the morphogenetic processes sequentially occurring in the belica early development—anlage of the raws of primary head neuromasts in its larvae and the subsequent formation of the ossified sections of the head seismosensory canals in its fry—are discussed. Keywords: Leucaspius delineatus, belica, fluctuating asymmetry, seismosensory canals, ponds, water mineralization, hardness cations


Fisheries and Processing of Aquatic Bioresources


On the possibility of using the industrial fishing gears and techniques for jellyfish harvesting in the Azov and Black Sea Basin 
Stafikopulo A.M., Andronov V.A., Vtyurina N.V., Gorbatyuk Ya.I. 

Abstract

Background. In the recent years, considerable development and formation of large aggregations of scyphozoans, namely barrel jellyfish Rhizostoma pulmo and moon jellyfish Aurelia aurita, has been observed in the Azov and Black Sea Basin. Relevance. Due to the  drastic  increase  in  the  biomass of  these gelatinous aquatic animals and their negative impact on various economic activities, currently the most prospective approach to reducing jellyfish abundance is  their harvesting for the further processing  (for various purposes) or amelioration of the environment (including their extermination). This article is aimed at consideration of  the main jellyfish harvesting techniques and gears used in the  world fisheries and  by  the Russian Federation, as  well as experimental designs developed in  the USSR; it  is also aimed  at the assessment of the possibility of applying the fishing gears and  techniques used in  the Azov and  Black Sea Fishery Basin for exploitation of other species of aquatic living resources to the jellyfish harvesting. Methods. The article references publications, informational materials,  scientific reports,  as well as the statistical data collected by the FAO and Federal Agency for Fishery (Rosrybolovstvo) on the global catches of jellyfish, including the data collected during applied research undertaken in 2023. Based on these materials and the data on the fishing operations in the Azov and Black Sea Basin amassed by the authors, the prospects of using industrial methods and commercial fishing gear for jellyfish harvesting (extraction) in the Azov and Black Sea Basin have been considered. Results. The fishing gears that  are  most promising for jellyfish harvesting have been identified, both coastal ones (pound nets) and  used off the board of a fishing vessel (trawl, elongated purse seine, and lampara net). Conclusion. The provided  data make it possible to outline the prospective approaches to jellyfish extraction in  the Azov and Black  Sea Basin.

Keywords: jellyfish, moon jellyfish, barrel jellyfish, Azov Sea, Black Sea, industrial fishing, coastal fishing, fishing gear, pound nets, trawl, vessel types


Informational Messages


More than half a century of service to science (on the anniversary of Doctor of Biological Sciences, Professor T.M. Bragina)
Zharlygasov Zh.B., Baubekova G.K., Rulyova M.M., Zeinelova M.A. 

Abstract

On February 26, 2024, Tatyana M. Bragina, Doctor of Biological Sciences, Professor of the Akhmet Baitursynuly  Kostanay  Regional  University,  Chief  Researcher  of   the   Azov-Black   Sea   Branch   of the Russian Federal Research Institute of Fisheries and Oceanography, Editor-in-Chief of the peer-reviewed scientific journal “Aquatic Bioresources and Environment” celebrated her anniversary. Tatyana  M.  Bragina  started her career at  the  Naurzum  State Nature  Reserve,  where she  was working  as a Deputy Director for Science for more than 17 years. T.M. Bragina has made an invaluable contribution to the study and preservation of the biological diversity of Kazakhstan. She initiated numerous environmental concervation and research projects  and  was in  charge  of  many  multidisciplinary scientific expeditions. Based on  the results of  these studies, the certification of  the primary lake systems  of a major part of Northern Kazakhstan has been carried out,  several  specially protected  natural  areas have been created, and five out of ten Ramsar sites of  the  Republic  of  Kazakhstan  have  been  recognized as wetlands of international importance. A special role in  the professor’s work  was played     by educational activities and by the development of a network of  specially  protected  natural  areas. Tatyana M. Bragina and her colleagues have also made a  crucial contribution to  creation and development of the scientific journal “Aquatic Bioresources & Environment”.

Keywords: anniversary, Tatyana M. Bragina, science, biological diversity, specially protected  natural areas, biological resources