Russian Sturgeon Research Articles

Analysis of the fluctuating asymmetry of bilateral traits in the Russian sturgeon grown in fish farms of various types

The aim of our work was to determine the influence of the Russian sturgeon breeding conditions on its phenotypic variability in the process of ontogenesis. The phenotypic variability identification work was carried out on the Russian sturgeon fingerlings and juveniles grown in three different fish farms: Sturgeon fish hatchery Bertyulskiy with an intensive pond type of breeding, Fish hatchery of Elektrogorsk SDPS named after R.E. Klasson with an intensive cage type of breeding and Mozhaisk production and experimental fish hatchery with an industrial use of RAS. In the first two farms, the fishes were studied postmortally, and in the third farm, the fishes were examined in vivo, by studying the fluctuating asymmetry of traits recorded on previously taken photographs. In the course of our study, it was found that the smallest impact on the organism development stability, estimated by the value of the average frequency of the asymmetric manifestations for trait (0.6), was found in the fish farms with an intensive method of reproduction in small ponds, as in the BSFH enterprise. The highest impact (0.8) was found in the farms using an industrial reproduction in RAS as organized in MPEFH. In the Elektrogorsk SDPS fish hatchery, an average value between the three compared farms, 0.7, was recorded, which is explained by the minimal temperature fluctuations of water due to the discharge of warm water into the cooling pond where the fishes are bred. Also, during the determination of the developmental stability level, estimated by the magnitude of the variance of the fluctuating asymmetry of bilateral traits, it was found that it depends on the temperature regime stability in the fish farms. It has also been established that the temperature changes in the spring-summer period lead to the formation of the physiological deviations in fishes, expressed by the fluctuating asymmetry of bilateral traits, mainly by the number of lateral and ventral scutes, as well as the number of rays of pectoral and ventral fins. The obtained data has high reliability at the level of Pі0.01 when comparing the above results.

Comparison of Fish Breeding Characteristics and Survival Rate of Offspring of Domesticated and Grown “from Eggs” Russian Sturgeon Acipenser gueldenstaedtii (Acipenseridae) Females, at Artificial Reproduction

Comparison of Fish Breeding Characteristics and Survival Rate of Offspring of Domesticated and Grown “from Eggs” Russian Sturgeon Acipenser gueldenstaedtii (Acipenseridae) Females, at Artificial Reproduction

Results of the first year of sturgeon hybrid breeding in an industrial fishery

The paper presents the results of rearing hybrid breeding (Siberian sturgeon × beluga sturgeon (SS×BS), Russian sturgeon × beluga sturgeon (RS×BS), and Russian sturgeon × kaluga sturgeon (RS×KS)) in a recirculating aquaculture system (RAS) and flow-through tanks at the Konakovo Division of the Branch for Freshwater Fisheries of the Federal State Budget Scientific Institution “Russian Federal Research Institute of Fisheries and Oceanography” (VNIIPRKH). The productive and biological characteristics of the arental sturgeon species used to obtain hybrids are discussed. The Siberian sturgeon × beluga sturgeon hybrids produced the most viable. The first stage of breeding in a RAS revealed that juvenile RS×BS and SS×KS hybrids had the best weight gain coefficient, with an average water temperature in rearing tanks of 16.9 °С. During the second stage of rearing in flow-through tanks, hydrological and hydrochemical conditions were generally similar for all intergeneric hybrids. This allowed us to compare the productive and biological characteristics. During the rearing period of 206 days in flow-through tanks, at an average water temperature of 19.5 °С and thermal constant of 3,519.2 degree days, SS×BS hybrid had the best weight gain coefficient and, consequently, the best average body weight (329 g). However, its survival rate was the lowest (48.8%). RS×BS hybrid showed intermediate results for the average body weight (249 g) and survival (72.3%). RS×KS hybrid showed the lowest growth and average body weight (190 g), but the highest survival rate (81.0%). It was discovered that the temperature conditions in flow-through tanks are quite favorable for sturgeon breeding during the summer. Thus, seeding for sturgeon hybrids can be carried out not only in a RAS, but also in flow-through tanks.

Vitrification of the ovarian tissue in sturgeons

The aim of this study was to test whether vitrification of sterlet Acipenser ruthenus and Russian sturgeon Acipenser gueldenstaedtii ovarian tissue through needle-immersed vitrification (NIV) is an efficient strategy for the preservation of oogonia (OOG) in order to supplement the current conservation efforts for these endangered fish species. Histological analyses of the gonads displayed that the ovaries of both species were immature and contained predominantly OOG and primary oocytes. The germline origin of these cells was verified by localization of the vasa protein through immunocytochemistry. NIV protocol was optimized by testing different equilibration (ES) and vitrification solutions (VS) containing various concentrations of dimethyl sulfoxide (Me2SO), propylene glycol (PG) or methanol (MeOH). In sterlet, the highest average viability (55.7 ± 11.5%) was obtained by using a combination of 1.5 M PG and 1.5 M Me2SO in the ES, and 1.5 M MeOH and 5.5 M Me2SO in the VS. In Russian sturgeon, the highest average viability (49.4 ± 17.1%) was obtained by using a combination of 1.5 M MeOH and 1.5 M Me2SO in the ES, and 3 M PG and 3 M Me2SO in the VS. To test whether vitrified/warmed OOG are functional, we have conducted an intra-specific transplantation assay to verify whether transplanted sterlet OOG will colonize the gonads of recipient fish. Fluorescently labelled cells were detected within recipient gonads at 2 and 3 months post-fertilization (mpf). Colonization rates of vitrified/warmed OOG (70% at 2 mpf and 61% at 3 mpf) were similar to those of fresh OOG (80% at 2 mpf and 70% at 3 mpf). This study has demonstrated that vitrification of ovarian tissue is an effective method for the preservation of OOG, and that the vitrified/warmed cells are functional and are able to colonize recipient gonads after transplantation similarly to the fresh cells. Since the vitrification procedure displayed in this study is simple and does not require complex and expensive laboratory equipment, it can be readily applied in field conditions, and therefore it can be invaluable for the conservation efforts of the critically endangered sturgeon species. However, care needs to be taken that despite the research conducted so far, donor-derived progeny was not yet obtained in sturgeons.

Anesthetic efficacy of clove oil and 2‐phenoxyethanol as hematological, histopathological and echocardiographic on broodstock Danube sturgeon ( Acipenser gueldenstaedtii )

Anesthetic efficacy of clove oil and <scp>2‐phenoxyethanol</scp> as hematological, histopathological and echocardiographic on broodstock Danube sturgeon ( <i>Acipenser gueldenstaedtii</i> )

Comparation of the structural characteristics and biological activities of chondroitin sulfates extracted from notochord and backbone of Chinese sturgeon (Acipenser sinensis)

To compare the structural properties and biological activities of chondroitin sulfate (CS) in two different tissues of Chinese sturgeon (Acipenser sinensis) and Russian sturgeon (Acipenser gueldenstaedti), we extracted their backbone cartilage CS (Cart-CS) and notochord CS (Noto-CS), and analyzed the CS structural properties using chromatographic and spectroscopic methods. The molecular weights of Chinese sturgeon Cart-CS and Noto-CS were 54.7 and 25.4 kDa, respectively, and the molecular weights of Russian sturgeon were 50.0 and 38.4 kDa, respectively. The disaccharide composition results showed that Cart-CS was mainly composed of CS-C, while Noto-CS was almost composed of pure CS-A. The antioxidant activity of sturgeon CS and its effect on collagen fibril formation were discussed. Sturgeon CS exhibited higher antioxidant activity than shark and bovine CSs. Sturgeon CS inhibited the self-assemble of type I collagen into fibrils. The inhibition effect of Cart-CS was higher than that of Noto-CS. The high value-added utilization of Cart-CS and Noto-CS will increase the value of sturgeon by-products. Furthermore, the disaccharide composition of CS in sturgeon depends on tissues of origin, but not on species. It means that the CS of Chinese sturgeon can be substituted by the CS of other commercial sturgeon. That will contribute to the protection of endangered species of Chinese sturgeon from illegal fishing and increase the value of commercial sturgeon by-products.

Assessment of morphophysiological indicators of sturgeon breeders

Studies were conducted to assess the morphophysiological indicators of sturgeon breeders in the conditions of the cage complex. It was found that a common feature for first–time mature beluga females raised in artificial conditions are relatively low values of eggs’ fertilization — 65,3±1,3%, with the number of eggs in 1 g — 46,0 pieces, in contrast to domesticated females where the indicators of eggs’ fertilization were higher by 27,1%. The yield of eggs from the body weight of domesticated beluga females was 2 times higher, unlike females raised on the principle of “from eggs to eggs”. It was noted that for beluga females raised in artificial conditions, the hemoglobin concentration values were 15,7% higher, in contrast to the indicators obtained from domesticated females. It was found that for beluga females raised in artificial conditions, the total protein indicators were 1,4 times higher. For domesticated Russian sturgeon females, there is a tendency for higher indicators of working fertility, for which significant differences were obtained (p &lt; 0.05). In Russian sturgeon females raised in industrial conditions, hemoglobin concentration indicators were higher by 14,5%, unlike adapted females, as a result, a similar trend is observed as with beluga females, it was found that for more productive fish, hemoglobin is lower, but within the reference values. The cholesterol level in the blood of domesticated and industrially raised Russian sturgeon females was slightly higher than the physiological norm. According to the statistical processing of the data obtained, the best indicators of total protein and glucose were noted for females raised in artificial conditions, however, these indicators of domesticated females were not critically low and were within the reference values.

The first outbreak of citrobacteriosis caused by Citrobacter gillenii in reared Russian sturgeon (Acipenser gueldenstaedtii) in Turkiye.

Russian sturgeon (Acipenser gueldenstaedtii) is an endangered fish species and also an important resource for the sturgeon aquaculture industry in Turkiye. Recently, a fatal and persistent bacterial disease occurred in the reared sturgeon kept in a trout farm in Turkiye. The disease outbreak has been with notable external signs including petechial hemorrhages and systemic anemia. This outbreak lasted for six weeks, and cumulative mortality reached around 35.00 - 40.00%. In this study, no parasitic and viral agents were observed in the sturgeons. Citrobacter gillenii was isolated from the diseased fish and identified by biochemical and molecular methods including API 20E and 20NE and 16S rRNA gene region sequencing, respectively. As a result, C. gillenii was identified for the first time in Russian sturgeon in Turkiye. The sequence was also deposited under the Genbank with MW057770 accession number. According to the result of disc diffusion method, bacteria were sensitive to enrofloxacin, streptomycin, amoxicillin and oxytetracycline and resistant to penicillin, trimethoprim/sulfamethoxazole, florfenicol and erythromycin. Also, ampC, sul1 and floR resistance genes were detected in the isolated bacteria. The results of this study provide important information for the diagnosis and treatment of this newly emerged disease of Russian sturgeon.

CRYOPRESERVATION OF REPRODUCTIVE CELLS OF MALE RUSSIAN STURGEON

Currently, cryopreservation of sperm is recognized as one of the promising ways to preserve the genetic diversity of fish, not only rare and endangered species, but also aquaculture objects. Scientific research was carried out in the scientific research center "Fisheries" of the S. Seifullin Kazakh Agro Technical University and the JSC "Republican Center for livestock breeding "Asyl Tulik" in 2022. The purpose of the research was to study methods of cryopreservation of Russian sturgeon sperm using cryoprotectors using dimethyl sulfide oxide with a concentration of 5% and 10% and methanol with a concentration of 3% and 8%. In the course of the research, generally accepted methods for assessing and freezing the sperm of the studied object were used. During the experimental work, the method of freezing the reproductive cells of the Russian sturgeon with a 15-minute exposure to -21°C in a box with subsequent immersion in a Dewar vessel was studied. The survival and lifetime of spermatozoa after defrosting were also studied. According to the results of the assessment of the quality of defrosted sperm of the Russian sturgeon, it was found that the most effective cryoprotective medium for cryopreservation is based on methanol with a concentration of 8%. The number of spermatozoa with translational movements in the three groups ranged from 23.8% to 31.2%. At the same time, the lifetime of spermatozoa in this cryoprotective medium was 118s. Methanol with a concentration of 8% provides the best resistance to oxidative stress experienced by cells during freezing. The results of the research make it possible to create a cryobank of the Russian sturgeon gene pool at fish hatcheries to preserve genetic diversity.

Whole-Genome Inter-Sex Variation in Russian Sturgeon (Acipenser gueldenstaedtii).

The Russian sturgeon (Acipenser gueldenstaedtii, AG) is an endangered fish species increasingly raised on fish farms for black caviar. Understanding the process of sex determination in AG is, therefore, of scientific and commercial importance. AG lacks sexual dimorphism until sexual maturation and has a predominantly octoploid genome without a definite sex chromosome. A conserved short female-specific genomic sequence was recently described, leading to the development of a genetic sex marker. However, no biological function has been reported for this sequence. Thus, the mechanism of sex determination and the overall inter-sex genomic variation in AG are still unknown. To comprehensively analyze the inter-sex genomic variation and assess the overall inter-species variation between AG and A. ruthenus (AR, sterlet), a related tetraploid sturgeon species, we performed whole-genome sequencing on DNA from 10 fish-farm-raised adult AG (5 males and 5 females). We produced a partially assembled, ~2390 MBp draft genome for AG. We validated in AG the female-specific region previously described in AR. We identified ~2.8 million loci (SNP/indels) varying between the species, but only ~7400 sex-associated loci in AG. We mapped the sex-associated AG loci to the AR genome and identified 15 peaks of sex-associated variation (10 kb segments with 30 or more sex-associated variants), 1 of which matched the previously reported sex-variable region. Finally, we identified 14 known and predicted genes in proximity to these peaks. Our analysis suggests that one or more of these genes may have functional roles in sex determination and/or sexual differentiation in sturgeons. Further functional studies are required to elucidate these roles.

Evaluation of Russian sturgeon (Acipenser gueldenstaedtii) Semen Quality and Semen Cryopreservation.

Simple SummaryThe decline in sturgeon populations, including Russian sturgeons, has reached alarming levels, threatening these species with extinction. The requirements for the meat of these fish, caviar and other products used in the textile, medical and food industries are constant or even on the rise. Reproductive biotechnologies seem to be the main solution to these problems, but the many unknowns related to the particularities of the species still place them far from the efficiency reached in some species of domestic animals. The development of fish farms for sturgeons and the intensification of reproductive biotechnologies is the main way in which the natural habitats affected by depopulation can be repopulated and to respond to the consumption and industrial requirements of the population. Our purpose is to contribute with additional novel information on the cryopreservation of sturgeon spermatozoa, as well as the evaluation of semen quality with the aim of developing a cryopreservation technique suitable for commercial breeding facilities.The alarming decline in sturgeon populations doubled by growing demands for sturgeon products, urge us to prevent the loss of these species. Fish stocking in natural habitats and developing fish farms are viable solutions, which can be successfully implemented with the help of reproductive biotechnologies. Despite the fact that semen cryopreservation is admittedly an important step for saving the Russian sturgeon, a reproducible standard method with good results has yet to be identified. Sperm quality assessment is essential for quantifying the impact of cryopreservation on spermatozoa. The purpose of our study was to provide additional information regarding semen cryopreservation and semen quality evaluation for the Russian sturgeon. Our study method is based on the use of two yolk-free extenders (with different cryoprotectants: DMSO and methanol) for freezing semen, using a simple freezing protocol. Parameters such as volume, concentration, motility, morphology and membrane integrity were evaluated. In conclusion, cryopreservation of Russian sturgeon spermatozoa using an extender containing methanol as cryoprotectant led to high egg fertilization percentages (72.67 ± 5.4%) even if the total motility values recorded for thawed semen were quite low (18–25%). Additionally, we identified two optimal stains for morphological studies and morphometry (Spermac stain kit and Trypan Blue Solution).

A different transcriptional landscape sheds light on Russian sturgeon (Acipenser gueldenstaedtii) mechanisms to cope with bacterial infection and chronic heat stress

Sturgeons are chondrostean fish of high economic value and critically endangered due to anthropogenic activities, which has led to sturgeon aquaculture development. Russian sturgeon (Acipenser gueldenstaedtii), the second most important species reared for caviar, is successfully farmed in subtropical countries, including Uruguay. However, during the Uruguayan summer, sturgeons face intolerable warmer temperatures that weaken their defences and favour infections by opportunistic pathogens, increasing fish mortality and farm economic losses. Since innate immunity is paramount in fish, for which the liver plays a key role, we used deep RNA sequencing to analyse differentially expressed genes in the liver of Russian sturgeons exposed to chronic heat stress and challenged with Aeromonas hydrophila. We assembled 149.615 unigenes in the Russian sturgeon liver transcriptome and found that metabolism and immune defence pathways are among the top five biological processes taking place in the liver. Chronic heat stress provoked profound effects on liver biological functions, up-regulating genes related to protein folding, heat shock response and lipid and protein metabolism to meet energy demands for coping with heat stress. Besides, long-term exposure to heat stress led to cell damage triggering liver inflammation and diminishing liver ability to mount an innate response to A. hydrophila challenge. Accordingly, the reprogramming of liver metabolism over an extended period had detrimental effects on fish health, resulting in weight loss and mortality, with the latter increasing after A. hydrophila challenge. To our knowledge, this is the first transcriptomic study describing how chronic heat-stressed sturgeons respond to a bacterial challenge, suggesting that liver metabolism alterations have a negative impact on the innate anti-bacterial response.

Эффективность применения некоторых БАВ в составе продукционных кормов для осетровых рыб

Bioflavonoids, also known as flavonoids, are substances with low molecular weight that are found in vascular plants. They are found in all parts of plants, but especially in photosynthetic cells and have a wide spectrum of action as antioxidants, enzymatic inhibitors, precursors of toxic substances, protection against ultraviolet radiation, and also participate in energy conversion. The article discusses the experience of using a new generation antioxidant – dihydroquercetin and an immunostimulator – arabinogalactan in feeding sturgeon fish. The objects of research in the work were: two-year-olds of Russian sturgeon, as well as dihydroquercetin, arabinogalactan and feed formulations for sturgeon fish species. In the process of work, the formulation of a full-fledged compound feed for sturgeon fish species was adjusted using the bioflavonoid dihydroquercin, an arabinogalactant immunostimulator, and the productive effect of feed on fish was evaluated according to fish-biological and physiological indicators. The obtained results complement the existing ideas about the fields of application of antioxidants, and also prove the prospects of using herbal remedies as antioxidant feed additives. The results obtained in the course of research can serve as a basis for improving technologies for the production of compound feeds when growing fish on an intensive basis.

First single-step genomic prediction and genome-wide association for body weight in Russian sturgeon (Acipenser gueldenstaedtii)

Russian sturgeon (Acipenser gueldenstaedtii)—a species of sturgeon—has a high economic value as a source of caviar and high-quality meat products. Genomic selection (GS) has the potential to shorten generation intervals and improve genetic gain for the key target traits of a breeding program. However, it has not been applied on sturgeon. We evaluated the performance of GS in breeding value estimation and carried out genome-wide association studies (GWAS) to dissect the genetic architecture of economically vital growth trait (body weight) in Russian sturgeon. Of a total of 3430 Russian sturgeons with phenotype records, 236 were sequenced. Through 10 replicates of fivefold cross-validation, we compared the accuracy of prediction obtained from a pedigree-based best linear unbiased prediction (BLUP), a single-step genomic BLUP (ssGBLUP), and a weighted ssGBLUP (WssGBLUP). We used single-step GWAS (ssGWAS) method to perform GWAS. The results showed that predictions made using ssGBLUP and WssGBLUP were 6.9% and 12.4% more accurate, respectively, compared with pedigree-based BLUP. Among the single-step methods, the performance of WssGBLUP was the best with the smallest mean squared (absolute) error. In addition, ssGWAS identified 3 potential SNPs with suggestive significance that were associated with body weight. Moreover, NOS1AP, CHMP4A, and RBMS1 genes were highlighted as functionally plausible candidate genes underlying the genetic architecture of body weight. These findings illustrate that the using GS in Russian sturgeon breeding could help in better selection of breeding candidates to facilitate complex economic growth trait.

The conservation paradox of critically endangered fish species: Trading alien sturgeons versus native sturgeon reintroduction in the Rhine-Meuse river delta

Sturgeons rank among the most endangered vertebrates in the world. Yet, the dwindling of wild sturgeon populations stands in stark contrast to their thriving status in aquaculture. Moreover, through the exotic pet trade, sturgeons are introduced outside their natural ranges where they may compete and hybridize with native species and transmit parasites and diseases. Here, we present an in-depth inventory of alien sturgeons in the delta of the rivers Rhine and Meuse, because several countries consider reintroduction of the native, critically endangered European sturgeon (Acipenser sturio). Our study is based on (a) an inventory of the industry of sturgeon cultivation; (b) reports on spread of alien sturgeons; (c) an analysis of pathways for introduction and spread; and (d) a risk assessment using the Harmonia+ protocol. In total, 11 alien Acipenseriformes (sturgeons and paddlefishes) were traded across an intricate network of >1000 distribution points in the Netherlands, Belgium, and Germany. Circa 2500 alien sturgeons were reported from 53 angling ponds and 64 other lakes and ponds, whereas circa 500 alien sturgeons were reported widespread across hydrologically connected waters. Species that posed the highest risk of introduction, establishment and spread are Siberian sturgeon (A. baerii), Russian sturgeon (A. gueldenstaedtii) and Sterlet (A. ruthenus). We recommend to implement stringent trade regulations and practical solutions to prevent spread of alien sturgeons. Measures must preferably be taken at the spatial scale of river basins.

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.

CHEMICAL COMPOSITION AND NUTRITIONAL VALUE OF MEAT OF DIFFERENT GENOTYPES OF STURGEON IN INDUSTRIAL PRODUCTION

The paper presents results of studies of nutritional and biological value of sturgeon of different genotypes. Experimental studies were carried out at OOO "Mulinskiy fish farm" of Nizhny Novgorod region in 2021. The object of the study was sturgeon of various genotypes (Russian sturgeon, Siberian sturgeon, hybrids of Russian sturgeon with Siberian and hybrids of Siberian sturgeon with Russian species). Chemical composition of fish meat in industrial production (percentage of moisture, protein, fat and ash) was determined. It was established that the hybrids of Russian sturgeon with Siberian species have the highest parametres of commercial (61.1 cm) and total length (76.2 cm), according to the size and mass characteristics of sturgeon at the age of two years, and the hybrids of Siberian sturgeon with Russian exceeded all other groups in terms of total body weight (2173 g), therefore, heterotic effect appeared, i.e. the ability of hybrids of the first generation to surpass parental forms in viability, fertility and other characteristics. It was shown that under the same conditions of keeping and feeding of sturgeons of different genotypes, pure species of Russian sturgeon occupy a predominant position in terms of protein and fat content - 26.43% and 8.18%, respectively. As for moisture and ash content, hybrids of Russian with Siberian - 73.77 and 0.61% and Siberian with Russian - 72.6 and 0.66% are ahead of their peers. Conclusions are drawn about the quality of meat and its value in nutritional aspect. Statistical processing of data from scientific and economic studies was carried out according to generally accepted formulae of variation statistics using Microsoft Excel programs.

Quality assessment of young of the hybrids “Lensky sturgeon × Russian sturgeon” and “bester” grown in a circulated water supply unit

The actual direction of modern aquaculture is the optimization of fish breeding processes by monitoring and managing environmental parameters and feeding regimes, reducing the influence of seasonality on technological processes in order to increase the yield of marketable products per unit area. The most optimal option for such industrial aquaculture is the use of recirculating water supply systems, which have proven themselves especially well in the cultivation of sturgeon fish. In commercial aquaculture, aimed at year-round production of high-value delicacy products in the form of meat and caviar, hybrid forms of sturgeon are becoming more common. The article describes the experience of growing juvenile hybrids Lensky sturgeon × Russian sturgeon and Bester in the pools installed in the recirculating water installation of Caspian Bekiresy Limited (Atyrau, Kazakhstan) is described. The article presents the results of monitoring the hydrochemical parameters of water, as well as the characteristics of the types of feed used in the cultivation of sturgeon hybrids at different stages of ontogenesis. The indicators of the initial and final weight, as well as the values of the absolute, average daily and relative growth of the yearlings of sturgeon hybrids were determined. A comparative assessment of the survival of sturgeon hybrid fry when grown in a recirculating water installation pools using water from an artesian well was carried out. The experience of growing sturgeon interspecific hybrids, based on the obtained fish-biological indicators, allows us to recommend them as a full-fledged replacement for parental species, the cultivation of which under artificial conditions has a low efficiency. Moreover, bester, which had high rates of growth and survival, is a more promising object for large-scale commercial cultivation in conditions of recirculating water supply installations.

Erratum to: Modeling for Scenarios for Stock Recovery of Russian Sturgeon Acipenser gueldenstaedtii in the Sea of Azov in the Absence of Natural Reproduction

Erratum to: Modeling for Scenarios for Stock Recovery of Russian Sturgeon Acipenser gueldenstaedtii in the Sea of Azov in the Absence of Natural Reproduction

Results of experimental studies on suppressing the growth of micromycetes (fam. Saprolegniaceae) on egg membranes of embryos of russian sturgeon and beluga in the incubation period

For successful development of aquaculture, fish farms have to be provided by effective means and methods to prevent and treat diseases of fish. Many drugs are limited for using in aquaculture, so the influence of each particular drug or chemical substance on the fish development should be investigated carefully. Effectiveness of chemical solutions for suppressing the growth of saprolegnium micromycetes on egg membranes and other tissues of sturgeon embryos during their incubation is evaluated. The experiment was conducted at the research and experimental base BIOS belonged to the Russian Res. Inst. of Fisheries and Oceanography, Volga-Caspian branch (CaspNIRKh) located in Astrakhan and included a series of observations on incubation of sturgeon eggs processed with solutions of some chemicals (Purple-K, sodium chloride, hydrogen peroxide) or drug (Iodinol). Two sturgeon species (russian sturgeon and beluga) were tested with measuring biological parameters of their embryos, as survival rate, contamination by saprolegnia micromycetes, number of abnormally developing embryos, and number of obtained prelarvae. The processing with 0.05 % solution of hydrogen peroxide (10 min. exposure) and with 0.90 % solution of sodium chloride (3 min. exposure) showed the best results: these solutions made the lowest negative effect on the embryos survival but reduced significantly infection of incubated eggs.