Sturgeon Hatcheries Research Articles

О расчете приемной емкости северо-западной части Каспийского моря в интересах искусственного воспроизводства водных биоресурсов в Волжско-Каспийском рыбохозяйственном бассейне

After release into the natural habitat, juveniles of semi-passable and passable fish, raised in sturgeon hatcheries and spawning farms of the Astrakhan region, do not stay in the river and roll into the sea. The main food objects for it are organisms of the “soft” benthos – crustaceans, worms and insect larvae. According to the results of research in 2020-2023, data from the analysis of the feed base during the period of the most intense food competition showed that the biomass of benthic invertebrates in the western part of the Caspian Sea is 121.1 thousand tons, production is 484.5 thousand tons. Taking into account the diets, age composition and abundance of each species of fish living in the water area of the settlement of factory juveniles, the volume of withdrawal of forage organisms is determined. livestock. The main consumers of “soft” benthos are representatives of cyprinid, atherine and goby fish species, which makes them the main food competitors of the produced juveniles. The reserve of “soft” benthos products is distributed among the factory juveniles according to the weight and daily diet of each species during the feeding period at sea. When calculating the permissible volume of release of each of the artificially reproducible water bodies, the coefficients of the maximum possible use of the feed base by juvenile fish and an increase in its number, taking into account death during adaptation to the natural environment, are used. Based on the calculations carried out, it is shown that the potential of the forage base of the western part of the Northern Caspian Sea is not a limiting factor in the stocking of the marine area with objects of artificial reproduction. The above method of calculating the receiving capacity is used in the preparation of an annual plan of measures for the artificial reproduction of aquatic biological resources.

The possibilities of using of captive and domestic broodstocks for saving of natural populations: 1. Acipenseriformes (part 1)

In last years the stocks of Russian species of sturgeons decreased to critical level which can be followed by their complete extinction in nature. As a result, the number of sturgeons beginning spawning migration into rivers are extremely small, but Astrakhan sturgeon hatcheries continue release annually about 35 mln fry using own broodstocks of two types — captive and domestic ones. However the releases of offspring of domestic broodstock are extremely discussible. On one hand, creation of such broodstocks could avoid the complete extinction of natural populations of Adriatic sturgeon Acipenser naccari in Po River and European sturgeon A. sturio in Gironde estuary. On other hand, long-term practice of commercial fish farming had shown that even the accidental refugees from sea cages or fresh-water ponds caused great harm to natural populations of same species. Hatchery individuals were undergoing different selection than fish in wild nature and had poorly formed reflexes (searching for food and avoiding predators). Besides a progressive decrease in genetic diversity with each generation could be seen in such fry due to limited number of parents (the Ryman-Laikre effect). However the creation of captive and domestic broodstocks of endangerous species and subspecies (Azov beluga Huso huso maeotica, fringebarbel sturgeon Acipenser nudiventris, Sakhalin sturgeon Acipenser mikadoi) and extinct populations (Baltic sturgeon Acipenser oxyrinchus) remains the only way to release hatchery juveniles. The first part of presented review is devoted to creation and using of captive and domestic broodstocks for conservation-type sturgeon fry releases in Russia and other countries.

The possibilities of using of captive and domestic broodstocks for saving of natural populations: 1. Acipenseriformes (part 2)

In last years the stocks of Russian species of sturgeons decreased to critical level which can be followed by their complete extinction in nature. As a result, the number of sturgeons beginning spawning migration into rivers are extremely small, but Astrakhan sturgeon hatcheries continue release annually about 35 mln fry using own broodstocks of two types — captive and domestic ones. However the releases of offspring of domestic broodstock are extremely discussible. On one hand, creation of such broodstocks could avoid the complete extinction of natural populations of Adriatic sturgeon Acipenser naccari in Po River and European sturgeon A.sturio in Gironde estuary. On other hand, long-term practice of commercial fish farming had shown that even the accidental refugees from sea cages or fresh-water ponds caused great harm to natural populations of same species. Hatchery individuals were undergoing different selection than fish in wild nature and had poorly formed reflexes (searching for food and avoiding predators). Besides a progressive decrease in genetic diversity with each generation could be seen in such fry due to limited number of parents (the Ryman-Laikre effect). However the creation of captive and domestic broodstocks of endangerous species and subspecies (Azov beluga Huso huso maeotica, fringebarbel sturgeon Acipenser nudiventris, Sakhalin sturgeon Acipenser mikadoi) and extinct populations (Baltic sturgeon Acipenser oxyrinchus) remains the only way to release hatchery juveniles. The first part of presented review is devoted to creation and using of captive and domestic broodstocks for conservation-type sturgeon fry releases in Russia and other countries.

Biological indicators and traceability of the origin of Russian sturgeon juveniles in the lower reaches of the Volga River and the north- western part of the Caspian Sea

The aim of the work: characterization of juveniles released from sturgeon hatcheries into the natural habitat with individual identification of individuals. Methods: Ichthyological researches in the Volga River and its watercourses were surveyed using a 4.5 m fry trawl; in the western part of the Northern Caspian, a trawl survey was carried out using a 9 m trawl and the developed grid of stations, adjusted to take into account the sea level decrease. The trophological material was processed by the quantitative-weight method, followed by the calculation of private and general indices of the filling of the digestive tracts. Molecular genetic methods for the analysis of microsatellite loci and sequencing of a fragment of the control region of mitochondrial DNA were used. Novelty: the origin of the Russian sturgeon and the contribution of artificial reproduction from Russian sturgeon hatcheries to the Volga- Caspian fishery basin were determined by molecular genetic methods. Results: The composition of food organisms and the degree of fattening of Russian sturgeon juveniles after their migration to the sea were determined. The contribution of artificial reproduction from Russian sturgeon hatcheries to the replenishment of the Russian sturgeon population of the Volga- Caspian basin in the period 2016–2021 for fingerlings was averaged 80 %. Practical significance: The intensity of downstream migration in the Volga River and its watercourses of juveniles released from sturgeon hatcheries was studied. The presented data was made it possible to determine the main localization sites of Russian sturgeon juveniles depending on the species composition and abundance of food organisms in the northwestern part of the Caspian Sea. Based on the results of genotyping of spawners at sturgeon hatcheries and juveniles caught in the Northern Caspian, an assessment was made of the effectiveness of the work of the sturgeon hatcheries in 2016–2021.

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.

ОСОБЕННОСТИ РЫБОВОДНОГО ОСВОЕНИЯ БЕЛУГИ ИЗ РЕМОНТНО-МАТОЧНОГО СТАДА ДОНСКОГО ОСЕТРОВОГО ЗАВОДА

The study conducted in 2022 has identified a lack of consistency in the results of the beluga artificial reproduction at the Don Sturgeon Hatchery (DSH). To obtain eggs, mostly the females born in 2001–2004 were used, out of which 31 females at age 18 reached their first maturity and one female at age 21 was a repeat spawner. The majority of first-spawning females produced eggs of low quality. During incubation, there was a substantial loss of fertilized eggs, and various anomalies of embryonic development were observed, which necessitated termination of the incubation of such eggs. The yield of one-day larvae from the eggs obtained from the first-spawning females and set for incubation was low, around 12 %. One of the reasons for the increased mortality rates and development anomalies in the larvae was low quality of the oocytes in the first-spawning individuals. A second-spawning female has shown satisfactory results; the fertilization rate was in line with the standard values, and no more than 17 % of the eggs manifested embryonic anomalies during their incubation. The yield of one-day larvae was 53.3 %. In total, 799 thousand one-day beluga larvae were obtained. The analysis of the cultivation practices at the Don Sturgeon Hatchery made it possible to identify the bottleneck points and critical junctures at some stages of the biotechnological process, as well as to give recommendations on improvement of the hatchery operation. An important prerequisite for obtaining good results is the physiological adequacy of beluga females, which is based, for the most part, on the living environment and feeding quality of the breeders and their replacement in the broodstock.

Size and age structure and population of the kaluga Huso dauricus and the Amur sturgeon Acipenser schrenckii (Acipenseridae) in the Amur river

Based on research findings from 1963–2021 the analysis of size-age indicators, qualitative structure of populations and changes in the number of kaluga Huso dauricus and Amur sturgeon Acipenser schrenckii in the river was carried out. Amur. It is established that in the period from the 60s. last century to 2008–2011 in the kaluga and the Amur sturgeon in the Amur River, there was a reduction in the size range and number of age groups, the proportion of mature individuals, the level of replenishment of populations with juveniles and abundance. The main reason for these changes is INN fishing (illegal, unreported and unregulated). According to the results of research in 2021, it was revealed that the modern number of kaluga exceeded the figures of the 60s. last century. In the Amur sturgeon, the process of population growth has not yet reached the historical values noted in the 1960s–1970s, but exceeded the indicators of the 1980s and subsequent years. Despite the noted positive points, at present, the population of kaluga in the river. Amur is characterized by the smallest average size and age over 60 years of study. The situation is better for the Amur sturgeon, which is due to the lower interest of fishermen in this species and the large volume of release of its juveniles from sturgeon hatcheries (ORZ). The reason for the positive dynamics is the artificial reproduction that has been developing on the Amur over the past decade, as well as the introduced set of restrictions on the Pacific salmon fishery. To further increase the number of Kaluga and Amur sturgeon in the river. Amur, it is proposed to maintain the current volumes of artificial reproduction of sturgeons and extend the restrictive measures in the salmon fishery for at least the next 10 years.

Experience, Principles and Parameters in the Sturgeon Quality Assessment by Anomalies in Early Ontogenesis (A Review)

Simple SummaryThe artificial reproduction of endangered Sturgeon in the transboundary Caspian basin has been performed by five states (Russia, Iran, Kazakhstan, Azerbaijan, Turkmenistan). The Russian Federation is the Sturgeon breeding leader with the largest number of Sturgeon Hatcheries—eight, which produce and release up to 61 million Sturgeon juveniles into the natural habitat. This technology was systematized and published in the Caspian states national and international scientific press and FAO. However, this guide does not sufficiently reflect the presence of Sturgeon anomalies in early ontogenesis, identified in the second half of the 20th century. The change in Sturgeon breeding paradigm from wild producers to brood stock spawners provides the incentive and basis for detailed study of Sturgeon anomalies. All previously known Sturgeon anomalies are divided into nine classes. Assessment of Sturgeon anomalies as predictors of their survival in the natural habitat will allow the evaluation of the Sturgeon stock status in the Caspian Sea.Purpose: Review the experience, principles and parameters of the sturgeon assessment quality by anomalies in early ontogeny. Results: Maintaining the number of sturgeon fish in the transboundary Caspian Sea is provided by five states (Russia, Iran, Azerbaijan, Turkmenistan, Kazakhstan) at 16 Sturgeon hatcheries, where their artificial reproduction is carried out. FAO recognizes Russia’s leadership in creating the basic technology for the sturgeon artificial reproduction, but the other four Caspian states also make a significant contribution to its modern optimizations. There is almost a century of tradition behind the technological development of artificial reproduction in sturgeons. During the artificial reproduction of sturgeons, anomalies in the structure and functions may occur, such as deformities, defects in organs and tissues, edema, hematomas, etc. The sturgeon anomalies classification is based on structural and functional principles. Identification of anomalies is carried out on the basis of a previously created classification, divided into nine large classes. Identification of sturgeon anomalies during the period of their artificial reproduction makes it possible to clarify the real value of replenishment of their stock. Methods: Analysis of professional scientific literature and practical guides. Conclusions: The presence and number of Sturgeon anomalies make it possible to determine their death percentage to calculate the real number of replenishment of the Caspian Sturgeon stock.

Features of kaluga sturgeon Acipenser dauricus and amur stergeon Acipenser schrenckii juvenile feeding in the Lower Amur

The aim of the work is to study the specifics and nutritional spectrum of juvenile kaluga and Amur sturgeon in the Amur on the halfway from the sturgeon hatcheries to the main feeding place — the Amur Estuary. There was Mysidacea in the food spectrum of juvenile kaluga from the Lower Amur, in 350–390 km from the mouth, in the first decade of July 2021. Mysids were found in 70% of the studied gastrointestinal tracts and their mass fraction was almost 44%. Fish played a secondary role in the diet of kaluga. The diet of the Amur sturgeon consisted mainly of Trichoptera (83.33%) and Chironomidae (42%) larvae. Mollusks were not found in the gastrointestinal tract of juveniles of both species feeding in the Amur riverbed. Both in diversity and the index of filling the gastrointestinal tracts, the diet of sturgeons in the Amur at the beginning of July 2021 was significantly inferior to the diet described by previous studies. The average number of identified objects in the gastrointestinal tracts of kaluga and sturgeon was 1.2 and 1.4, respectively; average gastric filling index — 41.1 and 28.8; the average value of the fatness coefficient for kaluga was 0.62, for sturgeon — 0.51. The different type of feeding and the range of food objects show that kaluga and Amur sturgeon juveniles are not food competitors in this section of the Amur. The high content of sand in the stomachs of sturgeons, 2.5 times higher by weight than the mass of the food in bolus, indicates the poverty of the sturgeon feed base on this section of the river in the conditions of abnormal flooding of the spring-summer season of 2021. In such hydrological conditions, food organisms — small fish, insect larvae — dispersed over large areas of the river floodplain, that made them hard-to-get for sturgeons living in the main channel and permanent channels.

The North American strategy of sturgeon breeding and possiibility of its realization in Russia

The main principles of sturgeon breeding in the USSR were developed in the works of A.N. Derzhavin, N.L. Gerbilsky, N.I. Kozhin, B.N. Kazansky, I.A. Barannikova, T.A. Detlaff and other ichthyologists. The so called “Soviet model of sturgeon breeding” relied on using of wild prespawning breeders selected from commercial catches in lower parts of rivers. After transportation to sturgeon hatchery sturgeons were injected by pituitary preparation. The ovulated eggs were inseminated, subjected to de-adhesion and incubated. One-day larvae were kept until the transition to exogenous nutrition and, after preliminary growing on live food in pools (combined method) or immediately (pond method) transferred to ponds. The average weight of fingerlings was 3 g. The modern “Russian model of sturgeon breeding” uses the formation of domestic broodstock because the hatchery releases cannot provide sufficient recruitment. The North American model of sturgeon breeding uses only “wild” breeders in prespawning or spawning state. The fingerlings are raised at sturgeon hatcheries to high weight, marked and released at age of 1 year, while the number of offspring of each female is limited. The survival rate of juveniles in nature depends on environmental condition and ecological capacity, so the optimal volume of releases is strictly calculated. The North American model of sturgeon breeding is used not only in the United States, but in the Danube basin, in the rivers of Turkey and in conservation programs for Chinese sturgeon of Yangtze River.

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

—A new model describing the dynamics of sturgeon (Acipenseridae) population unable to recover or ranked as depleted is proposed as a depleted artificially-stocking population (DAP) model. The model composed of two submodels is implemented in the R language. One of the submodels provides the opportunity to adjust the appropriate parameters used in a global model (the rate of natural mortality of a mature fish stock in a population and the artificial reproduction efficiency) with the optimization-based methods, while the second submodel deals with various scenarios for fish stock recovery over the forecast period. Scenarios are characterized by two parameters: the quantity of juvenils released by sturgeon hatcheries and the commercial fish catch decline caused by the illegal fishing practices and the fish catch for science-based targets. The estimates for the pattern of the Russian sturgeon Acipenser gueldenstaedtii in the Sea of Azov indicate that its stock may be recovered to the target level of 10 thousand tons with the baseline and optimistic scenarios by 2037—2048 relative to the artificial reproduction efficiency and the extent of illegal, unreported, and unregulated fishing. With respect to pessimistic scenarios, the stocks are not expected to recover.

Preservation of the genetic diversity of the sevryuga (Acipenser stellatus Pall) in conditions of artificial reproduction

According to the lactadehydrogenase locus, the genetic diversity of 9 samples of the Volga sevryuga of different origin was studied. In total, 733 pieces of young sevryuga, 99 pieces of producers and 107 pieces were studied. four-year-olds of sevryuga with MPERZ. To assess the genetic variability of lactate dehyrogenase allozymes, the method of polyacrylamide gel electrophoresis was used, as the most appropriate for assessing the influence of the environment in natural and domesticated populations. It is shown that the young sevryuga, grown in the conditions of 6 Astrakhan sturgeon hatcheries, differs significantly from the control group of natural producers. The LDH-3 lactate dehydrogenase locus is represented by 6 genotypes. 5 genotypes were found in producers, in the absence of only genotype 100/112. Genotypes 70/112 and 112/122 are missing in the samples from all plants and MPERZ, while genotype 70/70, which was found in excess at MPERZ, is also missing in three plants. However, in general, only 2 genotypes out of 6 are missing for all ARI. A study of the dynamics of the frequency of alleles in this set of samples showed that in 4 samples with ARI and on MPRZ there is no allele 112. However, in general, the ARI allele persists. Thus, it is shown that due to the different genetic variability of LDH-3 in juveniles from different acute respiratory infections, the genetic diversity in the samples as a whole approaches the indicators of producers. Therefore, the preservation of a variety of growing conditions for young sevryuga will contribute to the preservation of its genetic diversity.

Specific features of rearing of the Russian sturgeon juveniles in the Don Sturgeon hatchery in 2021

Specific features of rearing of the Russian sturgeon juveniles in the Don Sturgeon hatchery in 2021

Genetic characterization of Flavobacterium columnare isolates from the Pacific Northwest, USA.

Flavobacterium columnare is the causative agent of columnaris disease. Previous work has demonstrated a high degree of genetic variability among F. columnare isolates, identifying 4 genetic groups (GGs) with some host associations. Herein, a total of 49 F. columnare isolates were characterized, the majority of which were collected from 15 different locations throughout the US Pacific Northwest. Most isolates were collected from 2015-2018 and originated from disease outbreaks in salmonid hatcheries and rearing ponds, sturgeon hatcheries and ornamental fish. Other isolates were part of collections recovered from 1980-2018. Initial identification was confirmed by F. columnare species-specific qPCR. Study isolates were further characterized using a multiplex PCR that differentiates between the 4 currently recognized F. columnare GGs. Multiplex PCR results were supported by repetitive sequence-mediated PCR fingerprinting and gyrB sequence analysis. F. columnare GG1 was the most prevalent (83.7%, n = 41/49), represented by isolates from salmonids (n = 32), white sturgeon (n = 2), channel catfish (n = 1), ornamental goldfish (n = 1), koi (n = 3), wild sunfish (n = 1) and 1 unknown host. Six isolates (12.2%, n = 6/49) were identified as GG3, which were cultured from rainbow trout (n = 3) and steelhead trout (n = 3). Two isolates were identified as GG2 (4.1%, n = 2/49) and were from ornamental fish. No GG4 isolates were cultured in this study. The biological significance of this genetic variability remains unclear, but this variation could have significant implications for fish health management. The results from this study provide baseline data for future work developing strategies to ameliorate columnaris-related losses in the US Pacific Northwest.

Effect of water temperature on frog virus 3 disease in hatchery-reared pallid sturgeon Scaphirhynchus albus.

Ranaviruses are large double-stranded DNA viruses within the genus Ranavirus (family Iridoviridae) that are being detected with increasing frequency among aquacultured and wild fishes. In the USA, multiple sturgeon hatcheries have experienced ranavirus epizootics resulting in significant morbidity and mortality in young-of-year (YOY). Significant economic losses have resulted from repeated outbreaks of frog virus 3 (FV3), the type species for the genus Ranavirus, in YOY pallid sturgeon Scaphirhynchus albus reared at a hatchery within the Missouri River Basin. Water temperature and stocking density are known to influence the severity of ranavirus disease in ectothermic vertebrates. To determine the effect of water temperature on ranavirus disease in hatchery-raised S. albus, we conducted FV3 challenges at 2 temperatures (17 and 23°C) and compared cumulative survival over a 28 d study period. A mean (±SE) survival rate of 57.5 ± 13.2% was observed in replicate tanks of sturgeon maintained at 23°C, whereas no mortality was observed among sturgeon maintained at 17°C. In a second challenge study, we compared the effect of water temperature on disease progression by regularly sampling fish over the study period and evaluating lesions by histopathology and in situ hybridization, and by assessing viral titer and load in external and internal tissues using virus isolation and qPCR, respectively. Results suggest that temperature manipulation may be an effective mitigation strategy that sturgeon hatcheries can employ to minimize ranavirus-associated disease.

Investigation of starry sturgeon Acipencer stellatus in the Black Sea and Sea of Azov for AcIV-E infection

Specific sturgeon nucleocytoplasmic large DNA viruses (sNCLDV) infect several species of the Acipenseridae family. sNCLDV have previously been referred to as unclassified members of the family Iridoviridae. They have recently been moved from Iridoviridae to Mimiviridae family. One of these viruses, Acipenser iridovirus-European (AcIV-E), is present in farms across Europe where it has occasionally caused mild to severe losses in sturgeons. In this study, we provide data on AcIV-E search in a susceptible species such as starry sturgeon (Acipencer stellatus) from the Black sea and Sea of Azov. In 2020, starry sturgeons were sampled in Odessa region of the Black Sea and Zaporizhzhia region of the Sea of Azov. None of the sampled fish demonstrated pathological signs of disease and were healthy upon visual observation all individuals. Total DNA was extracted and submitted to a generic PCR targeting different fragments of major capsid protein (MCP) gene of AcIV-E. No virus-specific products were obtained in any starry sturgeon sample from both seas, while the expected products of MCP gene fragments as well as the fragments of beta-actin gene in control reactions were successfully amplified using fish and viral DNA of AcIV-E isolated from Siberian sturgeon in 2018–2019. Although AcIV-E is difficult to identify in asymptomatic wild fish, but it probably can play a role in starry sturgeon pathology across the Black Sea basin. A high risk of virus spread to wild populations is possible since this virus was identified in sturgeon farms upstream the Dnipro river. Therefore, AcIV-E, even in the presence of other pathogens, should be studied in sturgeon hatcheries as well as in possible vectors of disease, but the huge area of inspection could be a challenge.

Influence of growth on the biological and commercial productivity of Caspian great sturgeon Huso huso

Fisheries management has expanded from a traditional focus to a more holistic model based on a model describing the change in the number of generations of fish under the influence of age-dependent natural mortality and harvesting. We calculated the abundance, biomass, production, natural, total loss and catches from the conditional population of great sturgeon resulting from the replenishment of 1.0 million instances of fingerlings with different rates of linear and weight growth in the period 1931–1975. It was found that the size of fingerlings has the greatest influence on the abundance and biomass of conditional great sturgeon populations formed from juveniles. We found an increase in the length of annuals of 19.3%, with the biomass of the conditional population, its production and catch size increasing by 2.9 times. Thus, cultivation of sturgeon in sturgeon hatcheries (SH) and the release of large sized great sturgeon juveniles into the sea will significantly increase the efficiency of work of the artificial reproduction of stocks.

Influence of cultivation conditions on morphotype and phenotype of different-aged juveniles of Russian sturgeon (Acipenser gueldenstaedti Brandt, 1833)

Investigated the genetic variability of domesticated herds of the Russian sturgeon. This was selected three samples of fingerlings: the offspring of wild spawners and offspring domestizierung producers grown on Bertuliskan sturgeon hatcheries and the offspring domestizierung manufacturers grown at the hatchery Elektrogorsk TPP. Was investigated three polymorphic enzyme systems, the malate dehydrogenase (MDH), lactate dehydrogenase (LDH) and esterase (Ect). Genetic and biochemical studies carried out by electrophoresis. Review such factors as frequency of occurrence and level of heterozygosity. Investigated the relative abundance of Homo — and heterozygous genotypes in each enzyme system. To study morphological variability, we studied data on young Russian sturgeon caught from the Volga, Don and Kuban rivers, fingerling raised in a fish farm outside the range from the larval stage, fingerling raised in the conditions of the pilot fish-breeding workshop of the Novolipetsk metallurgical combine and fingerling raised in a fish farm using warm waste water of the Elektrogorskaya GRES-3 named after R. E. Klasson. We used both literary sources and our own data. The following features were selected for analysis: the number of beetles in the dorsal (Sd), lateral (Sl) and abdominal (Sv) rows. It is shown that the number of beetles in fingerlings grown in warm waters is significantly less than in fish from the natural environment.

Influence of the photoperiod and light intensity on growth performance, Melatonin and Insulin-like growth factors gene expression on Acipenser persicus during the embryonic stage

The effects of different light regimes (24L: 0D, 150 lux, 12L: 12D, 300lux, 0L: 24D, 0 lux, and control treatment) on growth, melatonin concentration, and Insulin-like growth factors gene expression of Persian sturgeon (Acipenser persicus) embryos were evaluated. Four groups of Persian sturgeon eggs (450 g) were incubated in Youshchenkov[X1] incubators with three replications for each treatment. The experiment was conducted during an 8- day period of incubation. Growth rate, plasma melatonin levels, and IGF-growth factors were investigated at 1, 4, and 8 days post fertilization. Results showed that higher mean weights growth were observed in fertilized eggs exposed to a 24L: 0D photoperiod with 150lux light intensity (p<0.05). The larval body length and hatching rate of fertilized eggs were significantly higher in embryos incubated at 12L: 12D with 300lux. The melatonin hormone level between sampling days and treatments were significantly different and it would be concluded that it may be related to the species. During the first-day post fertilization, the IGF-I and IGF-IR gene expression were significantly higher than other days. However, IGF-I and IGF-IR gene expression at different treatments showed no significant difference at day 4 and 8 post fertilization. According to the results, the stimulating role of IGF-I and IGF-IR gene expression in growth at the one-day post fertilization under different light regimes can be concluded. These findings suggest that the 12L:12D photoperiod with 300lux light intensity is the appropriate light regime for Persian sturgeon eggs incubation. The results of the present study would provide fundamental information for further use of light regimes during the early development of sturgeon larvae to optimize rearing protocols in sturgeon hatcheries.

Shaken, rattled and rolled: The effects of hatchery-rearing techniques on endogenous cortisol production, stress-related gene expression, growth and survival in larval Lake Sturgeon, Acipenser fulvescens

Sturgeon, one of the most endangered families of vertebrates, are of high conservation concern with population restoration efforts worldwide. Sturgeon species are often raised in conservation hatcheries to supplement wild populations with little understanding of effects of hatchery-related stressors on early development. Lake Sturgeon hatcheries deviate from natural conditions by coating adhesive embryos in clay to prevent clumping, embryos are then added to tumbling jars, colloquially referred to as McDonald Jars; a cone or cylinder-shaped container with constant flow, causing the embryos to roll and move throughout the water column. In the wild, Lake Sturgeon embryos adhere to substrate in fast-flowing rivers, where orientation is maintained throughout embryogenesis. In this study, we examined the effects of hatchery early-rearing environment, i.e. the use of tumbling jars, on gene expression, endogenous cortisol production, growth, and survival in larval Lake Sturgeon. We compared pre- and post-hatch tumbled larvae to non-tumbled larvae that were allowed to adhere to substrate throughout embryogenesis. We hypothesized that deviating from natural rearing conditions, with the use of tumbling jars, would result in changes to cortisol production, growth and mortality in post-hatch, tumbled larvae. Endogenous cortisol production was delayed one week for fish in the tumbled treatment (two-factor ANOVA; P < .05) when compared to non-tumbled fish. Tumbled fish were also smaller throughout development, with lasting effects on growth 62 days after hatching (P < .05). The tumbled fish had 23% mortality post-hatch compared to 6% in the non-tumbled group (Cox Proportional-Hazards Model; P < .0001). There were differences in gene expression in early development at specific time points, between the two treatment groups, in StAR and hsp70 (P < .05). The observed developmental effects on endogenous cortisol production and growth in the tumbled embryos could be counterproductive to the goal of producing a hatchery-reared fish that can survive in the wild. As conservation hatcheries aim to release individuals that will supplement and reproduce with wild populations, changes to developmental timing, growth and survival should be avoided. The findings of this study suggest that tumbling jars may not be appropriate in conservation hatcheries for Lake Sturgeon as they may have long-term negative consequences on individual fitness.