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Location of gonad in the body cavity of sterlet at maturity stage IV complete (F4c). Fish: age-30 months; total length/fork length-74.0/61.0 cm; weight-2.1 kg. Ovaries: weight-383 g; length-31.5/30.0 cm. A-location of ovaries in the body cavity; B-view of ovaries.
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... Our findings confirmed previous research that showed juvenile and young sturgeon migrated from shallow coastal areas (less than about 20 meters) to deeper areas as temperatures cooled (Chebanov & Galich, 2011). Our findings also confirmed the previously reported distribution of all five sturgeon species and the concentration of A. persicus in the Iranian coastal waters of the Caspian Sea. ...
... It should be noted that the non-invasive express method of early sex determination and gonad maturity stages with help of ultrasound diagnostics developed by M. Chebanov and E. Galich [3] is used in the practice of forming mature stocks of sturgeon fish. At the same time, it should be said that the ultrasound scanning method has been used relatively recently in the wide practice of sturgeon breeding [4][5][6][7][8]. ...
... It is known that the most optimal period for determining sex and maturity stages of sturgeon gonads is after artificial wintering with a gradual increase in water temperature from 2-3 ºС to 8-12 ºС [3]. For Siberian sturgeons of the Lena, Yenisei, Ob, Baikal populations and Siberian sterlet the wintering period, starting from the second stage of gonad maturity should be at least 4-5 months [2]. ...
The results of research work for the period from 2018 to 2023 on the use of early non-invasive functional ultrasound screening for the purpose of targeted formation of highly productive mature-brood stocks of Siberian sturgeon of the Ob, Yenisei, Baikal, Lena populations, European sterlet of the Kama population, Siberian sterlet of the Ob, Yenisei, Irtysh populations on main full-cycle industrial fish-breeding farms of Eastern and Western Siberia using water recirculation systems are presented in the article. Biotechnological methods for the formation of highly productive mature stocks using ultrasound monitoring are described. The number of individuals with pathologies and anomalies in the development of the reproductive system, liver, gallbladder and other internal organs were estimated; treatment methods were proposed. For the first time studies on the use of ultrasound for visualizing the gonads, determining the stages of maturity, detecting diseases of the heart, liver, gallbladder in salmon fish (trout, Atlantic salmon) grown in aquaculture have been carried out. For the first time ultrasound and histological studies were carried out to study the nature of “ink spots” on the skin of Siberian sturgeon Lena population from natural habitat. It was found that in the skin of sturgeon during pathology there was a growth of epidermal cells. Melanin melanocytes increased in both epidermis and dermis. At the same time there were no elastic fibers of the epidermis after painted according to Van-Gison. All these changes may indicate melanoma.
... Our findings confirmed previous research that showed juvenile and young sturgeon migrated from shallow coastal areas (less than about 20 meters) to deeper areas as temperatures cooled (Chebanov & Galich, 2011). Our findings also confirmed the previously reported distribution of all five sturgeon species and the concentration of A. persicus in the Iranian coastal waters of the Caspian Sea. ...
We used the bycatch of Caspian sturgeon to quantify the species composition, length structure, spatial and temporal distribution, temporal dynamics of relative abundance (indexed as catch‐per‐unit‐effort, CPUE), effects of fingerlings released, and to forecast future sturgeon stock status. Dynamic factor analysis of temporal changes in species CPUE was used to quantify relationships to environmental variables (sea surface temperature, chlorophyll‐a, sea surface level, and river discharge) during 2006–2022. We found that the Guilan subarea had the lowest relative abundance and differed from all other subareas. Fish abundance was highest in October and November, particularly in Mazandaran and Golestan coastal waters. Relative fish abundance declined significantly over time. Acipenser persicus was the most abundant species, followed by Aciperser gueldenstaedtii , Aciperser stellatus , Aciperser nudiventris , and Huso huso . The annual number of fingerlings released decreased during 2000–2021. Over the years, environmental variables such as sea surface level, sea surface temperature, and chlorophyll‐a showed different trends, with sea surface temperature generally increasing, chlorophyll‐a generally decreasing, sea surface level decreasing nearly linearly, and river discharge varying erratically without a trend in the southern Caspian Sea during 2006–2022. The relative abundance of all species decreased and was significantly related to sea surface level. Fish abundance was forecasted to decline by 2025, as sea surface temperature increases and sea surface level decreases. Illegal, unreported, and unregulated (IUU) harvest of sturgeon must be effectively regulated to ensure the survival and recovery of sturgeon populations in the Caspian Sea.
... Two thirds of the sampled sterlet population were females showing a clear deviation from an expected sex ratio of 1:1 (Holčík, 1989). Since sex determination based on external morphological traits was only partially successful in sturgeons (Chebanov & Galich, 2011), sex ratios in this study must be treated with caution. However, sex determination in the field was validated for 29 of 38 sterlets either through a non-lethal biopsy, successful reproduction or post-mortem examination for three individuals who died in the net. ...
... Eggs with dark color and with an absence of decomposition were visually selected from three different females, pooled, and used for fertilisation assay within 1 h of collection. All the manipulations with females and egg quality evaluation are done according to Chebanov and Galich (2011). ...
This study studied the possibility of sperm reactivation employing second motility activation, adenosine triphosphate (ATP) reloading, and regaining the fertilizing ability and the possibility of improvement in the fertilisation rate of reactivated sperm by supplementation with metabolites. The most crucial bioenergetic pathways during quiescent, motile, and reactivated states of sterlet (Acipenser ruthenus) spermatozoa were determined. Results showed that out of the studied pathways (glycolysis, mitochondrial respiration, and phosphocreatine-creatine – PCr-Cr shuttle system), PCr-Cr shuttle system was the most requested during the quiescent state. While after motility activation, no studied pathway had a significant energy supply contribution. Thus, the bioenergetic strategy to sustain sperm motility in sturgeon is similar to that in teleostean fishes. After termination of the first round of motility, the spermatozoa of sterlet were able to become motile and fertilise the egg cells after 1-h incubation in a reactivation medium. Mitochondrial respiration and the PCr-Cr shuttle system were shown to be active during the reactivation state. However, unlike spermatozoa of teleostean fishes, the sterlet reactivated spermatozoa did not demonstrate ATP reloading. This may indicate for the first time that the bioenergetic strategy during second motility activation in sturgeon sperm is divergent from cyprinids and salmonids. The fact that only part of spermatozoa can be reactivated is probably related to the existence of sperm subpopulations of specific intrinsic physiological properties. Further study of these properties will enhance our fundamental knowledge in fish spermatology and help increase the effectiveness of artificial fish reproduction.
... In A. ruthenus, the optimal temperature for the incubation of embryos is 13-16 C (Chebanov & Galich, 2011), although commercial hatcheries insist on 15-16 C for incubating embryos and rearing prelarvae and larvae (Gela et al., 2012). The exact limits of thermal tolerance in these developmental stages have not been reported for this species. ...
Sturgeons are ancient fish exhibiting unique genome plasticity and a high tendency to produce spontaneously autopolyploid genome states. The temperature profiles of the rivers in which sturgeon live and reproduce have been severely altered by human intervention, and the effect of global warming is expected to cause further temperature shifts, which may be detrimental for early developmental stages with narrow windows of thermal tolerance. The comparison of the performance of diploid and autopolyploid sturgeon kept at unfavourable temperatures contributes to scientific knowledge of the effects of polyploid genome states on organisms and can shed light on the ability of polyploids to cope with human‐induced alterations to natural conditions. Using the sterlet Acipenser ruthenus as a model species, we carried out conventional artificial fertilization, as well as the induction of the second polar body retention (SPBR), of the first mitotic division suppression (FMDS) and of the second polar body retention followed by the first mitotic division suppression (SPBR+FMDS). Two experiments were conducted to evaluate the effect of polyploidy on two basic performance parameters, survival and growth. In Experiment 1, fish belonging to untreated, SPBR‐, FMDS‐ and SPBR+FMDS‐induced groups were kept at 10, 16 and 20°C from the neurula stage until the end of endogenous feeding. In Experiment 2, larvae from the untreated and SPBR‐induced groups were reared at 10, 16 and 20°C after their endogenous feeding transition for 3 weeks. Based on our findings, we report that the embryos, prelarvae and larvae of triploid A. ruthenus do not differ from diploids in their ability to survive, grow and develop under suboptimal temperature conditions, while the survival of tetraploids was significantly reduced even at the optimal temperature and even more so at temperatures far from the optimum. This was also the case in the 2n/4n mosaics observed in FMDS‐induced group. Thus, we assume that in tetraploid and 2n/4n individuals, the limits of thermal tolerance are closer to the optimum than in diploids. We also conclude that the hexaploid genome state is probably lethal in A. ruthenus since none of the hexaploids or 3n/6n mosaics arising from the SPBR+FMDS induction survived the prelarval period.
... Temperature. The preferable water temperature for sturgeon farming is between 14 and 20°C, depending on species (Chebanov and Galich, 2013). Therefore, temperature range from 14 to 20°C is scored 255 which includes all sturgeon species (Fig. 3 a). ...
This study assessed and predicted the environmental impacts of sturgeon farming in three pre-determined spatial sites on the southeastern coasts of the Caspian Sea. In Fact, the present study developed a GIS-based mathematical matrices method to evaluate the environmental impacts of the development project. Initially, effective project activities and important environmental factors were identified. Next, a framework is created for interaction between project activities and their environmental impacts. Then, maps related to project activities and their environmental impacts were prepared. After that, the weighting of interaction effects was determined based on these maps. Finally, the results showed that spatial site number 1 (near the Gomishan Shrimp Farming Center) is the best place to establish a sturgeon farm and will have the least negative impact on the environment. The approach used in this study made the matrix method more complicated and led to more accurate results. The present study also emphasized that GIS is a powerful and effective tool for managing the environment and the decision-making process. This study also predicted that the expansion of aquaculture on the southeastern part of the Caspian Sea will create jobs and reduce poverty in this deprived region.
... Although initially sturgeon aquaculture was dedicated mainly to caviar production, in recent decades, demand for sturgeon meat has shown a positive trend with consumer acceptance [10], and this trend will be accentuated as the level of awareness of its undeniable nutritional values increases [11]. In caviar farms, females can be identified after 2-5 years when, depending on the species, they begin to differentiate sexually [12]. Therefore, for some larger species with late maturity, the males are commercialized long after they reach market size, which causes a decrease in profit of 30-40% [13]. ...
... For the second trial, the mean temperature was 20.71 ± 0.45 ˚C, pH was 7.39 ± 0.20, total ammonia nitrogen was 0.19 ± 0.23 mg/L, un-ionized ammonia was 0.02 ± 0.01 mg/L, and dissolved oxygen was 7.36 ± 1.13 mg/L. All parameters were considered adequate for sturgeon aquaculture [12]. The photoperiod was 10:14 h light:dark. ...
The study aimed to compare the growth performance and physiological responses of bester (B) and backcrossed bester ♀ × beluga ♂ (BB) in response to crowding stress under different stocking densities, as well as to establish a threshold stocking density for rearing BB in a recirculating aquaculture system (RAS) without welfare impairment. For this purpose, in the first trial (T1), B (181.15 ± 21.21 g) and BB fingerlings (181.98 ± 28.65 g) were reared in two stocking densities of 2 kg/m2 and 4 kg/m2 in fiberglass tanks (1 m3) for 6 weeks. In a parallel trial (T2), the BB hybrids (335.24 ± 39.30 g) were kept in four initial stocking densities, ranging from 5 kg/m2 to 12 kg/m2. The results of T1 revealed better growth indices (i.e., final mean weight, weight gain, specific growth rate) at lower stocking densities for both hybrids; however, in terms of growth performance, the BB hybrid showed better results when compared with the B hybrid. BB hybrids registered significantly (p < 0.05) lower serum cortisol and MDA and higher lysozyme than B hybrids, showing higher tolerance to crowding stress. Nevertheless, at higher densities, selected serum parameters (i.e., hematological indices, cortisol, glucose, protein, malondialdehyde, lysozyme) and growth performance indices used to evaluate the hybrids indicate that high stocking density could affect the growth and welfare of BB hybrids, and that the selected serum parameters could be used as good indicators for chronic stress caused by overcrowding conditions.
... As a result of mixing with the urine, the spermatozoa become able to initiate motility after dilution with water and to fertilize (Dzyuba et al., 2014), and at the same time, the large variability of spermatozoa concentration in sturgeon sperm samples exists intraspecifically between males and even in the ejaculates of the same male from sequential strippings . For sterlet, the sperm concentration tends to be 0.5-2.5 × 10 9 spz mL − 1 (Chebanov and Galich, 2013;Shaliutina et al., 2012;Linhart et al., 2020). The presence of such variability of sperm concentration in native sperm samples suggests the necessity of standardization of sperm concentration before cryopreservation. ...
... The high variability of the sterlet sperm concentration between different males obtained in our study supports the earlier findings Chebanov and Galich, 2013). Nowadays, it is clear that this variability is associated with a specific feature of the sturgeon urogenital structurethe connection of the urine and genital ducts, leading to the natural mixing of sperm with urine (Dzyuba et al., 2017). ...
One of the critical points in low temperature storage is the expense of storage capacities. Moreover, sperm concentration in a sample is not only a parameter for effective use of a cryobanks but also a parameter affecting cryopreservation outcomes. Sturgeon sperm in comparison to other species is significantly less concentrated due to the specificity of sperm maturation process, during which sperm is mixed with urine. In this study, we evaluated whether the artificial modification of the sterlet spermatozoa concentration before freezing can be useful during the routine application of sturgeon sperm cryopreservation.
The sperm was first concentrated by centrifugation of native sperm samples. Then, the excess of seminal fluid was collected. The concentrated sperm samples were further diluted with the same seminal fluid to obtain different sperm concentrations in suspension, and they were subjected to freeze-thawing. The percentage of post-thaw sperm motility depended on the sperm concentration in the samples. The highest post-thaw sperm motility was found in sperm samples with concentration of 0.2 and 1 × 10⁹ spz mL⁻¹. The sperm concentration of 3 × 10⁹ spz mL⁻¹, which is higher than the native sperm concentration in sterlet, was found to be appropriate for use in cryopreservation procedures since the sperm fertilizing ability remained at a high level even though a significant decline in percentage of sperm motility was observed. These findings supported the conclusion that the procedure of artificially increasing the sperm concentration before freezing could be useful for the reduction of the volume kept in cryostorage and to decrease the sample volume required for artificial fertilization.
... µS.cm -1 ) shows relatively low levels in the cage farm. The recommended water hardness values for sturgeon farms are 6-8 mg/l (Chebanov and Galich, 2013). In large reservoirs, hardness can change significantly throughout the year. ...
... When keeping thermophilic fish species, pH values in the range of 6.5-8.5 are considered optimal (Grigorjev and Sedova, 2008). For sturgeon species, water with a pH of 7-8 (Chebanov and Galich, 2013) is considered appropriate, and higher values of 7.5-8.5 (Vasilieva et al., 2006) are allowed when grown in cage farms. In our study, for most of the spring-summer period, the pH of the water was within technological limits. ...
... In our study, ammonium nitrogen varied from 0.14 (August) to 0.27 mg.dm -3 (July) during the spring-summer period, and in the autumnwinter one from 0.17 (December) to 0.96 mg.dm -3 (September). In September, the amount of ammonium nitrogen exceeded 0.5 mg.l -1 , cited by Chebanov and Galich (2013) as optimal for sturgeon farming, but below the 1 mg.l -1 specified by Kozlov (1998) as the norm for fish farming ponds. An important indicator in monitoring is nitrates, which are an end product of nitrification in reservoirs and can have a negative effect on fish at concentrations higher than 100 mg/l (Bregnballe, 2015). ...
A complex characterization of the physicochemical parameters of the water was performed in a sturgeon cage farm located in a dam in Southeastern Bulgaria during the different stages of the vegetation period. Water monitoring included key indicators for fish farming: temperature, dissolved oxygen, oxygen saturation, electrical conductivity, total hardness, pH, permanganate oxidability, biochemical oxygen demand over five days; ammonium nitrogen; nitrate nitrogen, orthophosphate content. There were significant negative correlation relationships: water temperature with dissolved oxygen levels (Rp =-0.702; P <0.05) and nitrate nitrogen (Rp =-0.867; P<0.01). Positive significant correlations were found between the electrical conductivity of the water with the water hardness (Rp = 0.636; P <0.05); water hardness with dissolved oxygen level (Rp = 0.855; P<0.01) and water saturation with oxygen (Rp = 0.958; P <0.001); dissolved oxygen and nitrate nitrogen in water (Rp = 0.647; P<0.05); phosphates with ammonium nitrogen levels (Rp = 0.598; P<0.05).
