Acipenser Stellatus Research Articles

Biological responses of stellate sturgeon fingerlings (Acipenser stellatus) immersed in HSP inducer to salinity changes

Changes in salinity is a stressful and energy-consuming process in fish which give rise to mortalities, especially in fish fingerlings that are more sensitive during the early stages of their life. In the present study, the effects of three salinities, 3‰ (downstream of river), 8‰ (estuarine), and 13‰ (the maximum salinity in the Caspian Sea), on HSP70 gene expression, cortisol level, immune response (lysozyme, complement C3, IgM), and antioxidant enzyme activities (SOD, CAT, T-AOC) of the stellate sturgeon fingerlings in the presence of HSP inducer compound (TEX-OE®) were evaluated. Our results showed that levels of plasma cortisol and heat shock protein (HSP70) in Acipenser stellatus fingerlings increased due to salinity changes. In the presence of the HSP inducer, HSP70 expression in both gill and liver was significantly increased, whereas cortisol level was notably decreased. Exposure to salinity changes resulted in an increase in antioxidant defense activities (SOD, CAT, and T-AOC) and immune response (lysozyme, IgM, and C3) in the presence of an HSP inducer. In conclusion, an HSP-inducing compounds can have a positive effect in strengthening the immunity and antioxidant system of sturgeon fingerlings by increasing the expression of the HSP70 gene against salinity fluctuations and generally increase the body's physiological tolerance.

Multivariate analysis of trace elements in starry sturgeon (Acipenser stellatus) spine in different areas of the Caspian Sea

Sturgeons are one of the most valuable species in the Caspian Sea. There, habitation of the seabed and feeding on benthic organisms makes this species a good indicator of trace element status. Thus, we aimed to determine the concentrations of 31 trace elements in the pectoral fin spine of starry sturgeons, and to evaluate the relationships between the different chemical elements. For this, a total of 40 starry sturgeons were obtained in a repopulation programme from the coastal waters north and south of the Caspian Sea. First, we used a multivariate analysis of variance to establish the differences between zones. Later, to assess relationships between trace elements, we used principal component analysis and cluster analysis. In general, the concentration of many trace elements did not vary between zones. However, some elements, including mercury or arsenic, were found in the north areas at higher concentrations.

Determination of the hybridization rate of Acipenser stellatus and Huso huso based on microsatellite analysis

On the basis of the in situ analysis of the sturgeon condition within the Lower Danube River, the aim was to carry out a research that would complement the results obtained from the monitoring and ultrasonic tagging methods. Thus, DNA samples were taken selectively from each ultrasonically tagged specimen in order to determine whether or not there is a possibility of hybridization between the species Acipenser stellatus and Huso huso. Thus, the microsatellite loci were investigated and certain parameters like diagnostic alleles, repeated sequences and specific molecular markers which were used to determine the degree of hybridism.

Studies of fish breeding biological and genetic parameters of stellate sturgeon (Acipenser stellatus Pallas, 1771) offspring obtained using native and cryopreserved sperm

Comparative results of experimental work on the study of stellate sturgeon offspring obtained using cryopreserved (experimental) and native (control) sperm, carried out at the scientific and experimental complex of aquaculture “BIOS” of the Volga-Caspian branch of VNIRO (CaspNIRKH) in this article were presented. Molecular genetic studies of cryopreserved sperm, females and males from the brood stock of the complex were carried out. In order to select the optimal parental pairs, calculations of genetic relationship of fish spawners were made. The scheme of the experiment was developed. The technological process of working with stellate sturgeon spawners was described: obtaining mature reproductive cells, insemination, incubation of caviar. Holding and breeding of the studied groups of stellate sturgeon juveniles up to standard weight was carried out. Each stage of the research work was subjected to comparative analysis. The genetic diversity of juveniles was studied. As a result of the work carried out, it was found that the group of fish obtained using of cryopreserved sperm had higher weight indicators, compared with the juveniles of the control group obtained from males from the brood stock of “BIOS”, by an average of 16%. In addition, the experimental group had a higher homogeneity compared to the control group, as evidenced by the values of the coefficients of variation. The survival rate of juveniles of the experimental group of fish was higher than the control group by an average of 10%. The stellate sturgeon obtained using cryopreserved sperm was characterized by higher values of the total number of alleles and the absence of a deficit of heterozygotes compared to the control group of juveniles, which is especially important for preserving the diversity of this valuable sturgeon species. The results of the research work carried out will help develop proposals for the formation of artificially created sturgeon brood stocks by replenishing them with juveniles obtained using cryopreserved sperm and having higher fish breeding biological and genetic indicators. This will allow the herd to have a stock of working material from different generations of sturgeon species, which is a promising factor for the conservation of aquatic biological resources and selection in commercial aquaculture.

Mid-infrared spectroscopy enabled rapid differentiation between fresh and frozen–thawed Sevruga (Acipenser stellatus) samples presenting different raw quality

Mid-infrared spectroscopy enabled rapid differentiation between fresh and frozen–thawed Sevruga (Acipenser stellatus) samples presenting different raw quality

Genetic monitoring of sterlet juveniles (Acipenser ruthenus) in the Volga river

The aim of the work was to carry out genetic monitoring of the natural reproduction of juveniles (larvae and underyearlings) of sterlet (Acipenser ruthenus Linnaeus, 1958), caught in the middle and lower spawning zones of the Volga River for the period 2021–2022, which is necessary and relevant in the context of a decrease in the number of sturgeon species of fish. The study of fish was carried out according to five nuclear markers and a fragment of the control region of mitochondrial DNA.According to the results of microsatellite analysis, sterlet individuals were characterized by species-specific dominant alleles and high values of the main indicators of genetic diversity: the number of alleles, allelic diversity and heterozygosity, and a slight deficit of heterozygotes was noted. By analyzing of the nucleotide sequences of the mtDNA D-loop region a high level of diversity of maternally inherited haplotypes was revealed, reflecting the number of females involved in natural reproduction. According to the monitoring data, no differences in the distribution and number of identified variants of the D-loop region were registered in the interannual aspect. During the study period, 48 sterlet mitochondrial haplotypes were recorded, of which 18 mtDNA variations were unique, occurring in the Volga-Caspian fishery basin. In the study of sterlet larvae by molecular genetic methods in the Volga River was revealed the process of hybridization between stellate sturgeon and sterlet (Acipenser stellatus × Acipenser ruthenus).

Physicochemical and Biochemical Properties of Trypsin-like Enzyme from Two Sturgeon Species.

This work aimed to determine the physicochemical and biochemical properties of trypsin from beluga Huso huso and sevruga Acipenser stellatus, two highly valuable sturgeon species. According to the results obtained from the methods of casein-zymogram and inhibitory activity staining, the molecular weight of trypsin for sevruga and beluga was 27.5 and 29.5 kDa, respectively. Optimum pH and temperature values for both trypsins were recorded at 8.5 and 55 °C by BAPNA (a specific substrate), respectively. The stability of both trypsins was well-preserved at pH values from 6.0 to 11.0 and temperatures up to 50 °C. TLCK and SBTI, two specific trypsin inhibitors, showed a significant inhibitory effect on the enzymatic activity of both trypsins (p < 0.05). The enzyme activity was significantly increased in the presence of Ca+2 and surfactants and decreased by oxidizing agents, Cu+2, Zn+2, and Co+2 (p < 0.05). However, univalent ions Na+ and K+ did not show any significant effect on the activity of both trypsins (p > 0.05). The results of our study show that the properties of trypsin from beluga and sevruga are in agreement with data reported in bony fish and can contribute to the clear understanding of trypsin activity in these primitive species.

РЕЗУЛЬТАТЫ ИССЛЕДОВАНИЙ АЗОВСКИХ ПОПУЛЯЦИЙ ОСЕТРОВЫХ РЫБ ПРИ ОСУЩЕСТВЛЕНИИ МОНИТОРИНГА ПРОМЫСЛА СТАВНЫМИ ОРУДИЯМИ ЛОВА У КУБАНСКОГО ПОБЕРЕЖЬЯ

Introduction. After depletion of the Russian sturgeon Acipenser gueldenstaedtii Brandt &amp; Ratzeburg, 1833 and stellate sturgeon Acipenser stellatus Pallas, 1771 stocks at the end of the 20th century, their abundance in the Azov and Black Sea Basin has been maintained through the release of the juveniles obtained by the means of artificial reproduction. Resulting from the strengthening protection of the aquatic living resources and gradually increasing number of the released juveniles, since 2014, as evidenced by the research studies, an increase in the population abundance of these fish species and their biomass is observed in the Azov Sea (from 42 t in 2015 to 998 t in 2022). Unstable state of the sturgeon populations in the coastal waters of the Azov Sea predicated the relevance of this work. Its aim was to investigate the distribution and age–length composition of the populations of the sturgeon fish species in the coastal waters of the Azov Sea. Methods. This study was based on the data on age–length composition collected over the course of the investigation of sturgeon by-catches in stationary pound nets in the coastal waters of the Azov Sea within an administrative unit Primorsko-Akhtarsky District (Yasensk and Achuevo Spits). According to its results, out of all sturgeon species, in the autumn season, the stellate sturgeon prevailed—53 %; the share of Russian sturgeon was 43 %, and for beluga sturgeon, it was 4 %. In summer, the Russian sturgeon share in the catches was 79 %, and for stellate sturgeon, it was 21 %. There have also been recorded some differences of the Russian sturgeon and stellate sturgeon length composition between the early spring and middle autumn, which can result from the fact that the sturgeon individual of greater length leave their wintering sites in the Azov Sea open waters earlier and sooner enter the coastal waters in spring. Conclusions. This study makes it possible to improve the assessment of the stock status and distribution for the sturgeon fish species in the Azov Sea.

ВЫПУСК МОЛОДИ ОСЕТРОВЫХ В АЗОВО-КУБАНСКОМ РАЙОНЕ С РЫБОВОДНЫХ ЗАВОДОВ ФЕДЕРАЛЬНОГО АГЕНТСТВА ПО РЫБОЛОВСТВУ В ПЕРИОД С 2016 ПО 2022 Г.

Background. By the end of the 20th and the beginning of the 21st century, artificial reproduction had taken up a key role in the sturgeon stock recruitment in the natural water bodies of the Azov–Kuban region. Relevance. The major part of artificial reproduction of sturgeon species is conducted in the fish hatcheries of the Azov–Kuban region under the authority of the Federal Agency for Fishery (Rosrybolovstvo). The aim of this study was to analyze the volumes of rearing and release of juvenile sturgeons into water bodies of fisheries importance in the Azov–Kuban region by fish hatcheries subordinate to the Federal Agency for Fishery. Methods. This article is based on the data recordings of the Azov-Black Sea Branch of the FSBSI “VNIRO” (“AzNIIRKH”) for the time range from 2016 through 2022. The data on 4 sturgeon hatcheries— Adygea, Achuevo, Grivensk, and Temryuk—are presented and analyzed. Results. An increase in the total number of juveniles of sturgeon species released into the natural habitat has been revealed. The highest values were recorded in 2021–2022. There has also been a disproportion in the number of released juveniles belonging to different species. Each year, sterlet Acipenser ruthenus accounted for a large share of released juveniles, for which the percentage ranged from 47.6 % in 2018 to 64.4 % in 2022. In recent years, the volumes of rearing and releasing the juveniles of this species have been increasing both quantitatively and in percentage terms. This fact can be explained by the earlier maturation of sterlet breeders, shorter intervals between repeated spawning, and the resultant larger number of “active” breeders of this species in the hatcheries. From 2019 through 2022, the share of the juveniles of sturgeon species released by the hatcheries of the Federal Agency for Fishery into the Protoka River, as compared to the Kuban River, increased from 55.0±0.10 % in 2016–2018 to 68.9±0.44 % (2019–2022). It resulted from the increase in the number of the sturgeon juveniles released into this water body, and not from a redistribution of release volumes between the Kuban and Protoka Rivers. Conclusion. In general, the artificial reproduction of sturgeon species by the fish hatcheries of the Federal Agency for Fishery in the Azov–Kuban Basin has shown a positive dynamics. However, it has also been found necessary to increase the scale of artificial reproduction of the most commercially valuable anadromous species: Russian sturgeon Acipenser gueldenstaedtii and stellate sturgeon Acipenser stellatus.

Genetic population structure of the critically endangered stellate sturgeon (Acipenser stellatus) in the Black Sea basin: Implications for conservation

Abstract Stellate sturgeon (Acipenser stellatus) is a species of great conservation concern throughout its range. Over the past century, it has experienced a dramatic decline in abundance and distribution in the Black Sea basin. Information regarding the genetic structure of the species is very limited in the region, despite its crucial importance for developing adequate management plans for the species’ conservation and recovery. Samples from 163 A. stellatus were analysed using mitochondrial and microsatellite DNA markers to investigate the species’ genetic characteristics in the north‐western and southern Black Sea. Both genetic markers revealed high genetic diversity (153 haplotypes and 264 alleles) and low genetic differentiation of marine and freshwater catches. The north‐western Black Sea population is undergoing a slight demographic expansion after a bottleneck event induced by overfishing and dam constructions. The genetic population structure indicates a single genetic cluster in the north‐western Black Sea region and signs of admixture of two genetic clusters in the southern region. It also provides the first evidence for a remnant reproductive stellate sturgeon micro‐population in rivers of Turkey and Georgia. A sturgeon fishing ban and stocking activities carried out during the last decades, largely without any prior genetic assessment of the sturgeon populations, added little conservation value. Outreach initiatives and urgent actions are required to foster the recovery of this Critically Endangered species in the region. Reconstruction of the connectivity of the rivers and the enhancement of habitats and spawning grounds are beneficial to all sturgeon species. An ex‐situ conservation programme for Turkish rivers which flow into the Black Sea would be beneficial to help conserve the genetic resources until the habitats and migration routes become functional. Moreover, genetic screening and recruitment programmes must be functional for all rivers flowing into the Black Sea.

Modern problems of artificial reproduction of sturgeon in the Volga‐Caspian basin

Aim. The aim of the study is to analyze the current state of artificial reproduction of the Caspian sturgeon and to identify the problems of reducing efficiency and ways to solve them.Discussion. The current critical state of the Caspian sturgeon, which accounts for up to 90% of the world's related resources, is of concern to the entire community, due to the threat of extinction of these relic individuals on the planet. This can be prevented by increasing the efficiency of reproduction. However, natural reproduction is practically reduced to zero, so the real and only possible solution is artificial reproduction. This analytical review presents five tasks, the successful solution of which will improve the current state of artificial reproduction in the Volga‐Caspian basin. The main task is the provision of fish breeding processes with producers, which, in the absence of fish of natural generation, are derived from brood stocks. Of particular concern is the threatened state of the Caspian beluga and stellate sturgeon. It is necessary to increase the release of their juveniles, for which financial stimulation of this activity is necessary. It is necessary to move more actively to the release of juveniles of an enlarged (7‐10 g) size and their export to feeding places in the waters of the Northern Caspian, which will contribute to an increase in fishing return.Conclusion. It is necessary to increase funding for research into the reproductive function of females and for artificial generation, as well as for the maintenance of production herds – a golden fund for restoring natural reserves. The attention of all the Caspian states should be drawn to the intensification of activities for the artificial reproduction of these unique fish species in the Caspian basin.

Dynamics of the Stellate Sturgeon (Acipenser stellatus Pallas, 1771) Ecological Niche in the Northern Part of the Caspian Sea Modeled on the Basis of Long-Term (1992–2006) Summer Monitoring Data

Dynamics of the Stellate Sturgeon (Acipenser stellatus Pallas, 1771) Ecological Niche in the Northern Part of the Caspian Sea Modeled on the Basis of Long-Term (1992–2006) Summer Monitoring Data

Sturgeons in large rivers: detecting the near-extinct needles in a haystack via eDNA metabarcoding from water samples

Sturgeon populations are declining worldwide and are the target of extensive conservation efforts. Addressed in several pieces of legislation, sturgeons have received considerable attention as flagship or umbrella species. Despite the need for a better understanding of the distribution and population status, the use of traditional sampling methods failed in the past, thereby hampering reliable assessments, a prerequisite for conservation. Here, we describe the development and application of an environmental DNA (eDNA) metabarcoding approach for detecting rare sturgeons in large rivers. Exemplarily, we developed a reference database for five native Danube sturgeons (Acipenser stellatus, Acipenser gueldenstaedtii, Acipenser ruthenus, Acipenser nudiventris, and Huso huso) and two non-native species (Acipenser baerii and Acipenser transmontanus), assessed these ex situ, and used eDNA as a detection tool along the entire length of the Danube (Europe, ~ 2850 km) and major tributaries. In ex situ analyses, all assays yielded positive amplifications for the assessed sturgeon species. In the Danube, the presence of A. ruthenus was confirmed at 14 of 29 sites (48.3%), and in 2 of 18 tributary sites (11.1%), providing the first comprehensive large-scale biogeographical snapshot of this species. Relative number of reads assigned to A. ruthenus varied between 0 and 2.5%, with sites registering positive detections being clustered in 3 sections of the Danube. Our findings enabled us to confirm the advantages of eDNA monitoring over traditional sampling methods for comprehensive whole-river snapshot studies of sturgeons conducted on a large geographical scale, and therefore we consider it to be a promising approach for application in conservation measures, fisheries management, scientific studies, and adaptive management plans for sturgeons on a global scale.

MODELING THE DYNAMICS OF THE ECOLOGICAL NICHE OF STARRED STURGEON (&lt;i&gt;ACIPENSER STELLATUS&lt;/i&gt; PALLAS, 1771) IN THE NORTHERN PART OF THE CASPIAN SEA BASED ON SUMMER LONG-TERM MONITORING DATA (1992-2006)

Models of ecological niches of stellate sturgeon ( Acipenser stellatus Pallas, 1771) in the northern part of the Caspian Sea based on long-term monitoring data (1992-2006) are presented. The analysis of the results of the study of the long-term patterns of the spatial distribution of alien species of polychaete Hediste diversicolor , mollusc Abra ovata and crustaceans are reported. Estimates of the effect of abiotic and biotic factors on the formation of ecological niches of the stellate sturgeon in the eastern and western regions of the northern part of the Caspian Sea are presented. Graphical schemes of the spatial distribution of stellate sturgeon in different years of monitoring in the plane of two main components (PCA) are given. It is shown that the salinity of water and the density of crustaceans are the leading factors for constructing models of ecological niches.

Некоторые виды рыб, имеющие рыбохозяйственное значение в Нахичеванской части Аракского водохранилища

The study is dedicated to the identification of fish species that have fishery importance and distributed over the Nakhichevan part of Aras water reservoir. The study was conducted between 2018 and 2021. Samples were collected by means of nets, strainers and fishing rods. Materials (samples) captured by Nakhchivan Fish Farm were also used during the study. 14 fish species with fishery importance were identified in the study area: Acipenser stellatus stellatus n. cyrensis, Rutilus rutilus subsp. caspicus, Ctenopharyngodon idella, Aspius aspius subsp. taeniatus, Luciobarbus capito, Barbus lacerta subsp. cyri, Blicca bjoerkna subsp. transcaucasica, Abramis brama subsp. orientalis, Cyprinus carpio, Hypophthalmichthys molitrix, Carassius auratus subsp. gibelio, Capoeta sevangi, Silurus glanis and Sander lucioperca. The article provides detailed information on 6 species with fishery importance (Aspius aspius subsp. taeniatus, Blicca bjoerkna subsp. transcaucasica, Abramis brama subsp. orientalis, Carassius auratus subsp. gibelio, Cyprinus carpio, Silurus glanis) that bear essential significance for Nakhchivan territory.

A Multistep DNA-Based Methodology for Accurate Authentication of Sturgeon Species.

The sturgeons (order Acipenseriformes) are caviar producers and some of the most valuable fish species worldwide. Due to different reasons, wild populations are now at the brink of extinction. The high demand for caviar has led to the development of aquaculture for restocking and caviar production. Since the caviar from different species has different prices depending on the quality and attempts of commercial fraud based on species substitution have been found, correct species identification is more than necessary. We report a new multistep methodology for an accurate species identification based on both nuclear and mitochondrial markers. Our test integrates data from the analysis of microsatellites (Afu19, Afu34, Afu39, Afu54, Aox27, AoxD234, AnacC11 and AnacE4), nuclear gene markers (RPS7, vimentin and rhodopsin) and mtDNA barcoding to give a reliable molecular diagnostic for five sturgeon species (Huso huso, Acipenser stellatus, Acipenser ruthenus, Acipenser gueldenstaedtii and Acipenser baerii). In addition to species identification, our methodology allows the identification of bester, sterbe and best beluga hybrids, but also the identification of hybrids of unknown origin. This methodology has a good potential to contribute to the conservation of highly threatened sturgeon populations and also to the traceability of their products.

The full-length transcriptome sequencing of three sturgeons reveals the occurrence of whole genome duplication event.

Sturgeon is one of the ancient fish species with the fossil records over 200 million years ago. However, the sturgeon genomes are rather complicated, owing to several rounds of genome polyploidizations, which makes it difficult to assemble a high quality genome so that only a few studies analyze their whole genome evolutions (WGDs). This study applied the PacBio sequencing technology to sequence the full-length transcriptomes of blood samples of octoploid Huso dauricus, octoploid Acipenser schrenckii and tetraploid Acipenser stellatus. A total of non-redundant 33,407 transcript assemblies of the three sturgeons were finally generated and fully annotated with different gene function databases, as well as the predictions of simple sequence repeats, transcription factors and long non-coding RNAs. Data valuation exhibited that annotations of the three transcriptomes had the higher quality than those of the previously sequenced sturgeon genomes. A phylogeny of eight typical sturgeons was constructed using the low copy genes, which illustrated that Acipenser and Huso might share a single origin. The sturgeon WGDs were parallelly timed by calculating the divergence times of 2-member gene clusters and heterozygous-SNP-carried genes, which both suggested the occurrence of the WGDs later than 150 mya. The full-length transcriptome sequences were supposed to be the reliable reference data for the study of sturgeon.

ISOLATION OF STRAINS ANTAGONISTIC TO PATHOGENIC AEROMONADS FROM NATURAL POPULATIONS OF FISH AND BOTTOM SEDIMENTS

Increasing production efficiency and ensuring the environmental safety of commercial fish farming facilities through the creation of modern preparations for the treatment and prevention of diseases is a topical area of aquaculture. The study of the current situation shows that the factors limiting the possibilities of sustainable entry to the market, providing fish farms with high-quality highly productive breeding material and increasing the volume of commercial fish farming products are diseases of the breeding facilities. The development of new highly effective probiotic preparations for the prevention and treatment of aquaculture facilities will not only reduce the economic costs associated with the death of breeded fish, but will also help to increase the viability of fish, the accumulation of nutrients in tissues, and the correction of the microbiocenosis of the aquatic environment. The aim of the study is to search for natural Bacillus antagonistic strains promising for creating probiotics. The strains were isolated from bottom sediments and cyprinids of natural populations. In the course of the work, the antimicrobial spectrum of action of bacilli against the causative agents of aeromonosis, furunculosis and bacterial hemorrhagic septicemia (BHS) was studied. Aeromonas test-strains were isolated from sterlet, sturgeon, stellate sturgeon, trout, carp, grass carp, silver carp, grown in conditions of pond farms.

Acipensor Stellatus, Rutilus (Rutilus) Caspicus, Leuciscus Cephalus Orientalis of the Fauna of the Nakhchivan Autonomous Republic Faunistic Analysis of Fishes

Summarizing the obtained literature materials and the results of our research, it was determined that 33 fish species or subspecies consisting of 6 groups, 9 chapters and 28 genera are distributed in the waters of Nakhchivan AR. Acipenser stellatus - A fairly large fish, its adult individuals in the ichthyofauna of Azerbaijan vary in body length from 105 to 225 cm and weight from 9 to 73 kg. The body stretches. Rutilus rutilus caspicus - A number of esophageal teeth, gingival teeth are sparse and rough. It is the only widespread species in Azerbaijan. The body, slightly flattened on the sides, is covered with fairly large scales. The eyes are large, the iris is red. Leuciscus cephalus orientalis - Fish is distinguished by broad and rigid forehead, cylindrical and large scales. The eyes are big and bright.

Changes in HSP70 Gene Expression, Immune Response, and Enzyme Indices in the Stellate Sturgeon (Acipenser Stellatus) Fry Exposed to an Organophosphate Pesticide in the Presence of HSP Inducer

Changes in HSP70 Gene Expression, Immune Response, and Enzyme Indices in the Stellate Sturgeon (Acipenser Stellatus) Fry Exposed to an Organophosphate Pesticide in the Presence of HSP Inducer