Comparison of Chick Quality, Health, and Inflammation from Two Hatchery Environments

Hatchery contamination can result in ingested or inhaled microbes that may modify colonization of the intestinal and respiratory tract, with potential to influence early growth, inflammation, and overall health. Six experiments were completed to compare chick quality, inflammation, and health between two hatcheries (H1 and H2). On embryonic d0, 45 eggs from the same breeder flock were set at each hatchery. On d0, length, abdominal height, navel and leg abnormalities, and self-righting were measured for 36 chicks/hatchery, yolk sacs were weighed, and crop/cloaca swabs were cultured from 12 chicks/hatchery. On d7, mid-ileum and ceca were cultured from 12 chicks/hatchery. On d0 and d7, body weight (BW) and intestinal weight were measured, lung/air sac swabs and liver were cultured, and liver and air sacs were scored for health. Blood was collected on d0 and d7 for serum alpha-1-acid glycoprotein concentrations in Exp 1 and 2. Data was analyzed using Student’s t-test or χ2, significance p < 0.05. On d0, BW, length, yolk free BW, and intestinal weight were greater for H2 chicks (p < 0.05). Liver bacterial recovery was decreased in H2 on d0 (p < 0.05) and there were fewer average leg and righting abnormalities in H2 (p < 0.05). Decreased lactase positive Enterobacteriaceae were noted in H2 in crop/cloaca and lung/air sac swabs (p < 0.05), and of alpha and beta hemolysis in crop/cloaca swabs, and alpha and gamma hemolysis in lung/air sac swabs (p < 0.05) on d0. By d7, only alpha hemolytic bacteria were increased in lung/air sac swabs of H2. Based on factors measured, chicks from H2 showed favorable microbial colonization, starting quality, and improved health on d0. While not sustained through d7, differences in d0 microbial recovery may have shifted microbial development and potentially influenced immune response development. These experiments elucidated the importance of hatchery environment on early chick quality, microbial colonization, overall inflammation, and chick health.

Genetic Variation of Wild and Hatchery Populations of the Pacific Oyster Crassostrea gigas Assessed by Microsatellite Markers

Microsatellite DNA technique was used to detect the genetic variation between five hatchery populations of the Pacific oyster from China and two wild populations from Japan. Seven microsatellite loci screened in this study showed high polymorphism in both hatchery and wild populations, as observed in an average number of allele per locus （19.1-29.9） and average expected heterozygosity （0.916-0.958）. No significant difference in average allelic richness or expected heterozygosity was observed between Chinese hatchery populations and Japanese wild populations. Pairwise Fsr values and heterogeneity tests of allele frequencies showed significant genetic differentiation between all populations. According to the neighbor-joining tree constructed on the basis of the Dc distance, the seven populations fell into three groups showing a clear division between hatchery and wild populations, and between the northern and southern hatchery populations. Assignment tests correctry assigned high percentages （97%-100%） of individuals to their original populations and demonstrated the feasibility of microsatellite analysis for discrimination between populations. The information obtained in this study is useful for designing suitable management guidelines and selective breeding programs for the Pacific oyster in China.

Bioconversion of Fish Hatchery Waste as Feed in the Production of Live Feed

Purple Non-Sulfur Bacteria (PNSB), also known as phototrophic bacteria are widely distributed in both freshwater and marine environment and capable to grow in wide range of substrates. In this study, Bacterium Rhodobacter sphaeroides strain UMS2, a freshwater isolate was used in this study in utilization of fish hatchery waste. This study was conducted to determine the nutritional values of bioprocess product that was grown in fish hatchery waste. Finally, the waste bio-converted product was used as feed supplement to monitor the growth performance of live feed Tubifex spp. Inoculum of Rhodobacter sphaeroides strain UMS2 was developed in 112 synthetic media and 48-h culture of 30% (v/v) inoculum was used in fish hatchery waste during the bioprocess. The nutritional values of bio-converted product, except total ash (%), were not significantly improved with 30% (v/v) inoculum of Rhodobacter sphaeroides, strain UMS2. Feeding trial in bloodworm (Tubifex spp.) with bioconversion product conducted for 15 days to monitor growth (w/v) of live feed. Initial growth 1.42 ± 0.001 g/L of Tubifex spp. was stocked in 15 × 75 × 15 cm plastic tray connected with recirculated system. Tubifex spp. was observed to be comparatively higher (1.55 ± 0.12 g/L) while fed in the product that contained bacterium than the growth (1.44 ± 0.15 g/L) of Tubifex spp. fed in the bioconversion product of without bacterium. The inoculums size (30%) of bacterium not enough to support the growth of Rhodobacter sphaeroides, strain UMS2 in the bioconversion process to improve the nutritional values. However, while used as feed supplement it improved the growth performance of the Tubifex spp. So, bacterium Rhodobacter sphaeroides, strain UMS2 has potentiality to be used as feed supplement in the production of live feed.

Multiple Antibiotic Resistance and Heavy Metal Resistance Profile of Bacteria Isolated from Giant Freshwater Prawn (Macrobrachium rosenbergii) Hatchery

In this article, antibiogram and heavy metal resistance profile of bacteria isolated from giant freshwater prawn （Macrobrachium rosenbergii） hatchery in Malaysia are described. Although giant freshwater prawn was introduced into Malaysia since the 1980s, there was no database information on antibiogram and heavy metal resistance profile of bacteria from giant freshwater prawn （34. rosenbergii） hatchery in Malaysia. Therefore, this study was carried out to determine the effectiveness of antibiotic and heavy metal resistance profile to control bacterial diseases in M. rosenbergii hatchery. The results can provide valuable information for local M. rosenbergii post-larval producer. Antibiotic sensitivity test was carried out by disk-diffusion method against 15 types of antibiotics as follows： oxolinic acid （2 μg）, ampicillin （10μg）, erythromycin （15μg）, furazolidone （15 μg）, lincomycin （15μg）, amoxicillin （25 μg）, colistin sulphate （25 μg）, doxycycline （30μg）, florfenicol （30 μg）, flumequine （30 lag）, nalidixic acid （30μg）, tetracycline （30μg）, oleandomycin （15μg）, fosfomycin （50μg）, and spiramycin （100 μg）, whereas heavy metal resistance profile of the present bacterial isolates was determined by 2-fold agar dilution technique. In this study, 5 types of bacteria were successfully isolated; they were Aeromonas spp. （n = 77）, Escherichia coli （n = 73）, Edwardsiella spp. （n = 62）, Salmonella spp. （n = 75）, and Vibrio spp. （n = 43）. The result showed that furazolidone was the most effective antibiotic to control the bacteria isolated in this study, approximately 89.7% of the bacterial isolates were sensitive to this antibiotic. Multiple antibiotic resistance （MAR） index indicated that the hatchery water source and M. rosenbergii post-larval and sediment tanks were at high-risk exposure to the tested antibiotic. Furthermore, all the tested heavy metals （Cd2＋, Cr6＋, Hg2＋, and Cu2＋） failed to inhibit the growth of the bacterial isolates. Therefore, it indicated that the water source of the hatchery is contaminated with both antibiotic residues and heavy metal.

Research in migration route of hatchery released Chinese shrimp(Fenneropenaeus chinensis) in the Bohai Bay using method of SSR marker

This study provides new insights for the hatchery released Chinese shrimp(Fenneropenaeus chinensis),including proportion,dynamic migration route,after they were released into nature for stock enhancement using a new strategy quite different than ever.Chinese shrimp were sampled at 22 survey stations during two investigation voyages acrossing 74 survey stations in the Bohai Sea from July 16 to August 9 in 2015.Among 289 sampled individuals during the second voyage,totally 155 shrimps were identified as hatchery shrimp released into the Laizhou Bay at mid-May in 2015 based on finger-print of eight SSR(simple sequence repeats)markers,and the proportion of hatchery released shrimp in recapture samples were from 41.30%–85.71%in each station with an average value 53.63%,which verified a previous view point that up to 90%of autumn season Chinese shrimp landing in the Bohai Sea were composed of hatchery released.Meanwhile,the dynamic migration route of hatchery released shrimp revealed that part of released shrimp migrated heading northwest along the west coast of the Bohai Sea up to the Bohai Bay but just remained at the Laizhou Bay until over-wintering migration at midOctober when they initiate over-wintering migration.Present unnatural spring season shrimp fishing model cut the throat of spawner shrimp chance to swim back to their respective spawning plants at each spring,it still no chance to clarify whether the hatchery released shrimp could replenish to the reproduce population and complete a whole life cycle as same as their natural relatives.

Inbreeding and genetic diversity analysis in a hatchery release population and clones of Rhopilema esculentum based on microsatellite markers

Ten microsatellite markers were used to analyze the levels of genetic diversity and inbreeding in a hatchery release population of Rhopilema esculentum Kishinouye （Scypbozoa： Rhizostomatidae）. A total of 85 alleles were detected in 600 individuals. Within-population levels of observed （Ho） and expected （He） heterozygosity ranged from 0.152 to 0.839 （mean=0.464） and from 0.235 to 0.821 （mean=0.618）, respectively. The polymorphism information content （PIC） of each marker ranged from 0.207 to 0.795 with an average of 0.580, indicating that the hatchery population maintained a high level of genetic diversity. Inbreeding levels were estimated in the hatchery population and the inbreeding coefficient was 0.203. This result revealed that a certain level of inbreeding occurred within the population. Meanwhile, we also determined genetic diversity at the clone level. Several polyps from the same scyphistomae were genotyped at the ten microsatellite loci and there was virtually no difference in their genotypes. Furthermore, we calculated the probabilities of exclusion. When both parents were known, the average exclusion probability often loci was 99.99%. Our data suggest that the ten microsatellite markers can not only be used to analyze the identity of individuals but they can also be applied to parentage identification. Our research provides a theoretical basis and technical support for genetic diversity detection and reasonable selection of R. esculentum hatchery populations. These findings support the use of releasing studies and conservation of R. esculentum germplasm resources.

A Survey of Hatchery Waste Management Practices

A survey of major chicken meat hatcheries in Australia was undertaken in 2008 to identify how hatchery waste is currently managed. A weekly average of 10.4 tonnes of waste is produced by chicken meat hatcheries. The cost of disposal （average $127/tonne） and availability of disposal sites is an emerging issue. The majority of hatchery waste is sent to land fill or for composting, with some rendered for use as pet food. Hatchery wastewater is mostly used for irrigation or disposed directly into the sewer. Most of the hatcheries have no environmental issues with hatchery waste on site but some report odour problems. Some hatcheries would like to treat the waste on site so that it could be sold as a commodity or to use methods to separate liquid from solid waste and recycle water.

Characterization of Finfish Hatchery Waste for Value Added Product

Commercial fish hatchery generates waste both organic and inorganic;the sources are primarily from uneaten food and fish feces. Conventional methods of treating hatchery wastes will increase the operating cost and become extra burden in production. It is necessary to develop a new research application of this nonconventional resource and reduce the negative impacts of hatchery waste on the environment. The whole project is to utilize hatchery waste through bioprocess for probiotic fortified live feed production. In this study, the chemical composition of hatchery waste was determined to understand the suitability waste to get value-added derived products through bioprocess. Composite samples were collected everyday and dried in an oven at a temperature of 65°C until complete dryness. Dried samples were mixed well and grinded into fine powder. The analytical parameters like total solids, ammonium nitrogen, nitrite, nitrate and phosphate were determined from the freshly collected samples. Total nitrogen, total phosphorus and total potassium were determined from the dry samples. Total solids, ammonium nitrogen, nitrite, nitrate and phosphate-phosphorus were observed in the ranged from 75 - 82 mg/L, 0.25 - 8.5 mg/L, 0.05 - 1.9 mg/L, 0.04 - 6.7 mg/L and 4.1 - 16.7 mg/L respectively. On the other hand, the mean content of 3.75% total nitrogen, 1.80% total phosphorus and 0.15% potassium were determined in dry hatchery wastes. The analytical parameters are useful and demonstrate that the nutrients in both fresh and dry waste will be supportive for the growth of microbes in the bioprocess system.

The Novel Hatchery Facilities Based on Main Effect Factors of Seedling Rearing of Mud Crab （Scylla spp.） in China

Mud crab is an important economic crab cultured in Pacific and Indian Ocean Rim. Based on the knowledge about the characteristic requirements in seedling cultivation of mud crab under high-temperature conditions, this article reviews and discusses major factors affecting seedling rearing of mud crabs, and presents novel hatchery facilities for improvement of seedling rearing. The results of our study showed that major factors affecting seedling cultivation of mud crabs included： （1） the micro-ecological environment and characteristics of water quality in seedling rearing ponds, and a double-bottom cultivation facilities and cultivation techniques that meet the requirement; （2） salinity, temperature, light, NOE-N, NH4-N and other physical and chemical environmental factors that affect survival probability ofzoaea; （3） the total number of bacteria in the zoaea-culturing pond and the number of vibrio in seedling rearing; and （4） nutritional intensification with bait organisms in zoaea-culturing. To meet and improve these conditions, a novel hatchery facility was designed to modify the pond roof in accordance with the characteristics of the zoaea stage, and improve natural light thermostat control in seedling cultivation of mud crabs.

The identification of individuals with hatchery and natural origin in a mixed sample of Amur River chum salmon by Otolith microchemistry

We estimated the proportion of hatchery and natural fall spawning chum salmon returning to the Amur River using chemical markers specific to hatchery-origin fry.We used otolith microchemistry technique to identify fish with artificial origin among returning spawners.First,we found that juveniles of artificial origin had higher values of the Sr:Ca molar ratio of the otoliths’edge zone compared with juveniles of natural origin,what can be related to the use of rearing feed produced from raw materials of marine origin rich in strontium.Then we observed that most of the spawners from Anyuisky Hatchery and from the Amur River mouth at the start of the spawning migration has also the higher value of Sr:Ca molar ratio of the juvenile zone of otoliths.Also,adults with higher values of the Sr:Ca molar ratio are characterized by a skewed right in the peak of the age distribution.Both,the age structure and phenological shift in the time of spawning migration of individuals with higher value of the used chemical marker corresponds to results of studies on hatchery-produced chum salmon completed at different parts on Northern Pacific.The results of this study will be used in the management of Amur fall chum salmon fisheries,and also demonstrates the necessity of the development of specific measures for increasing the survival of juvenile anadromous salmonids released at large rivers and exposed to prolonged freshwater migration to the ocean.As a further application of the methodology,we plan to identify the markers specific to each of the hatcheries and main spawning tributaries belonging to Amur River catchments.This will be an important step in the evaluation of the contribution of different stocks in mixed fisheries and also in the estimation of the effect of hatchery releases on naturally spawning stocks of Amur fall chum.Following to,our results may indicate the applicability of this approach for the determination of artificial-origin fish in a mixed sample of the Amur fall chum salmon.

Low-cost mobile hatchery produced silver barb(Barbodes gonionotus)fingerling:it's growth and economic performance in intensive culture system

Objective:To explore the growth performance of low-cost mobile hatchery produced silver barb(Barbodes gonionotus)fingerling comparing with typical one,field laboratory complex hatchery.Methods:Assigning Treatment I and Treatment II stoked with low-cost mobile hatchery and field laboratory complex hatchery originated fingerling of silver barb in plastic circular tank.Results:The average weight gain(g/day)of fish was 0.18 and 0.16 g,length gain(cm/d)0.03 and 0.02,gross yield 0.09 and 0.08 kg/tank per month,net yield 0.03 and 0.01 kg/tank per month respectively in Treatment I and Treatment II.The growth of low-cost mobile hatchery produced silver barb was higher(P<0.05)although SGR(%/d)was 1.63 and 1.89 and FCR was 2.57 and 2.55 for Treatment I and Treatment II,correspondingly and survival was 100%in both cases.In case of economic efficiency,total operating cost were BDT 68.91 and 67.41,revenue BDT 107.35 and 89.30,net profit BDT 38.44 and 21.89 and BCR 1.55 and 1.32 respectively in low-cost mobile hatchery and field laboratory complex hatchery produced fishes.Conclusions:The fry from both origins showed more or less similar growth performance and none of them was superior.Considering the economic feasibility in both cases,it is assumed that the intensive culture of silver barb is possible at field level.

Viral Diseases of Olive Flounder in Korean Hatcheries

In order to elucidate the state of diseases, especially viral diseases, and to prevent viral diseases from occurring in olive flounder hatcheries, a range of studies, including epidemiological study, were performed from 1997 to 2003. The location of the hatcheries investigated includes several representative sites in the east （Kangnung, Uljin, Pohang, Yangsan, Ulsan, Pusan）, south （Wando, Changheung, Goheung, Yeosu, Namhae, Tongyeong, Geoje, Jeju） and west （Seosan, Kunsan, Gochang, Yeongkwang, Mokpo, Chindo） costal areas of the Korea Peninsula. A total of 2000 cases have been examined in 7 years, in which mortality caused by viral agents accounts for 22%, or 446 cases. Mortalities associated with viral infection considerably increased from 14% in 1997 to 27% in 2003. A variety of viral diseases were observed, and the occurrences of viral epidermal hyperplasia, viral ascites and viral deformity, viral nervous necrosis, and hirame rhabdoviral disease are 14%, 51%, 25%, and 8% respectively. By investigating the viral infection of broodstock flounder, the infection rate of marine birnavirus （MABV） in hatcheries was identified to be approximately 30%, therefore, it is highly necessary to acquire and keep non-infected broodstock fishes.

Parentage determination of black sea bream(Acanthopagrus schlegelii)for stock enhancement:effectiveness and loss of genetic variation

The stock enhancement programs for black sea bream Acanthopagrus schlegelii have been conducted in China for a fewyears.However,little information has been reported concerning the effectiveness and genetic effect of black sea bream stock enhancement.In order to detect the contribution of released individuals in Zhujiang River Estuary(ZRE)and Daya Bay(DB),six microsatellite markers were used to identify the hatchery-released individuals.In addition,this pedigree of hatchery populations(broodfish and hatchery-released offspring)was traced to detect the number of effective parents(N_(e)),the inbreeding coefficient and the decrease of genetic variability in the reproduction.The pedigree reconstruction showed that at least 69(out of 93)broodfish had offspring.The estimated N_(e) was 54.8,consequently the inbreeding coefficient was 0.91%.The genetic diversity of hatchery-released offspring was lower than that in that of broodfish(heterozygosity alleles,0.727-0.774),some alleles(number of alleles,61-69)and genetic variance were lost during reproduction.It was observed that wild samples had higher levels of genetic diversity compared with hatchery populations as well as recaptured samples in releasing area.A total of 128 hatchery-released black sea bream were identified among 487 recaptured samples in ZRE,while a total of 15 samples were identified among 96 samples in DB.In summary,there was a high survival of released fish.N_(e)vertheless,the results provided evidence to consider a loss of genetic variation in hatcheryreleased stock and a negative genetic effect of the stock enhancement.

Mesocosm Hatcheries Using Semi-intensive Methodologies and Species Diversification in Aquaculture

Mesocosm hatcheries using semi-intensive culture methodologies are characterized by large tanks （40 m3） for fish larvae production at low densities （2-8 larvae/L）, with live prey production within the tank supplemented by exogenous sources of feed. Due to the high biological quality of larvae produced and low level of technological input, these methodologies are regarded as an interesting option to meet the increasing fry demand from the aquaculture industry. This study aimed to describe the experience at Centro de Maricultura da Calheta, Madeira Island, Portugal, with the establishment of a mesocosm hatchery for the production of marine fish larvae. Production trials were initiated with gilthead seabream Sparus aurata. This larval species presented faster growth in total body length （TL） per day （TL = 3.7516e~ ~293day, R2 = 0.9404）, higher survival rate （SR = 31.9%） and comparable swimbladder inflation rates （SB = 90%） to those of larvae reared with intensive methodologies. High larval performance was obtained with two candidate species for aquaculture： the red porgy Pagruspagrus （TL = 3.212e~~39day, R2 = 0.995; SR = 15.3%; SB = 95.7%） and the white seabream Diplodus sargus （TL = 3.6355e~~413day, R2= 0.9824; SR = 25%; SB --- 100%）. Testing ofa 110 m3 mesocosm rearing tank with white seabream larvae revealed limitations associated to larger tanks namely, the amount and quality of live feed required daily. First trials with striped jack （Pseudocararoc dentex） larvae resulted in low larval survival （0.04%）, but the use of a white tank avoided culture management constraints related to positive phototropism. The present results suggest that a mesocosm using semi-intensive methodologies may contribute to species diversification and consequently, to the sustainable development of aquaculture.

A Degassing Inlet Structure for Aquaculture Ponds

Structures separating fish hatchery ponds from open spring water sources must restrict fish movement from the pond to the spring, allow for constant water flow, and potentially reduce incoming spring water gas supersaturation. This article describes a novel inlet structure that fulfills those requirements. In addition, it requires minimal maintenance, and allows for the quick and easy removal of debris in the event of partial plugging. This simple aluminum structure consists of a mount for attachment to the inflow pipe and a terminal splash plate with aeration holes. The splash plate is perpendicular to the water flow during normal operations to both prevent fish from jumping into the pipe and aerate the incoming water. However, it can be easily swiveled upward for the efficient removal of debris. Use of the inlet structure consistently decreased gas supersaturation in the spring water as it entered the fish production pond. By decreasing gas levels and maintaining water flows, potentially hazardous fish health issues can be avoided by using this structure. In addition, this relatively inexpensive and simple device will greatly reduce the labor required for removing debris compared to traditional screens.

Occupational Noise Levels in Two Fish Rearing Buildings at an Aquaculture Facility

Occupational noise is commonly encountered during aquaculture. This study documented noise levels in two buildings at a production fish hatchery, a tank room with 32, 1.8-m diameter tanks, and a rearing pavilion with 32, 6.1-m diameter tanks. With water flowing to all of the tanks in the tank room, mean noise levels were 68.4 dB, and significantly increased to 73.0 dB during tank cleaning and 73.2 dB when intermittent automatic feeders were running. The highest tank room values of 77.1 dB were recorded directly next to individual tanks during cleaning. With water flowing to all of the tanks in the rearing pavilion, mean noise levels were 70.2 dB. A significant increase to 76.1 dB was observed when the pavilion tanks were being power washed, with the highest value of 83.2 dB recorded immediately adjacent to the power washer. Although none of the noise levels exceeded regulatory limits, the use of techniques to reduce occupational noise in aquaculture environments is recommended.

Interbreeding of mouth malformed and crooked-back Clarias gariepinus （Burchell, 1822）

Interspecific crossing was carried out among and between two strains of Clarias gariepinus with mouth malformation and crooked-back traits to determine the source（s） of their deformities and the effects of these morphological deformities on their growth and survival. Synthetic ovaprim hormone was used for their inducement at 0.5 mL/kg of the brood stock body weight at FEDAK integrated farm, Ado-Ekiti, Nigeria. Under indoor management, highest mean survival rate was 73% recorded in the hybrid of female mouth malformed C. gariepinus x male crooked back C. gariepinus and the least mean survival rate was 70% recorded in the mouth malformed C. gariepinus parental. Under outdoor rearing crooked back C. gariepinus parental had the highest mean growth rate （11.20 grammes） while the hybrid of the cross between female crooked back C. gariepinus and male with mouth malformed C. gariepinus had the least mean growth rate （8.63 grammes）. High frequency of occurrence of various morphological aberrations （0.92%） was recorded in the mouth malformed C. gariepinus parental and low frequency of occurrence （0.57%） of morphological aberrations recorded in hybrid of female crooked back C. gariepinus x male mouth malformed C. gariepinus. The reoccurrence of some of these morphological deformities in Clarias is a mystery based on their consistent occurrence even under a very good hatchery management. More research works still need to be done in this area of study of Clarias to unravel the mystery behind this morphological imbalance, because the deformities play special roles in discouraging both the farmers and the consumers of this fish.

Artificial enhancement of sturgeon stock in freshwater reservoirs:A case study on sterlet Acipenser ruthenus of the Kama reservoir

The paper presents the results of the sterlet sturgeon Acipenser ruthenus reintroduction into the Kama Reservoir(Perm Krai,Russia)by sterlet fry from hatcheries into the reservoir since 2001.The effectiveness of hatchery releases was evaluated by monitoring gillnet sampling 2014-2020.The results showed that the species was reported throughout entire Kama Reservoir,which contrasts with 1988-1994 data,when the species was registered only at the upper part of the reservoir near the Kama River mouth.The highest number and biomass values of catch per unit effort(CPUE)of the sterlet were found in submerged river channels-the deepest habitats with flow conditions which are close to the ecological requirements of the species.The distribution of the sterlet within the channel biotopes of the reservoir is defined by reduced variability.The biggest individuals and the widest size range of the sterlet were typical for the upper area of the reservoir and Chusovskoy Bay,which have the greatest flow.The smallest sizes were typical for fish from catches near the dam of the reservoir,which is consistent with the published data on the distribution of sterlet in reservoir conditions.The presented results may indicate the artificial formation of the sterlet stock in the Kama Reservoir maintained by hatchery releases.The revealed distribution of the sterlet in the reservoir determines the direction of further research on natural reproduction and thus formation of an artificially formed population.Also,future studies are required to assess the possibility of hybridization of the sterlet of artificial origin with natural populations of the species,since the low genetic diversity of the sterlet released into the Kama Reservoir which can lead to irreversible loss of genetic individuality of the natural stocks of the species in the catchment of upper course of the Kama River.