Fish Farming Research Articles

Bacillus Sp. as Potential Probiotics for Use in Tilapia Fish Farming Aquaculture – A Review

Abstract Aquaculture is a crucial and rapidly expanding industry in global food production. Fisheries are also an essential socio-economic activity, providing abundant resources and remarkable prospects. However, due to the deteriorating ecological environment, aquatic animals are often exposed to traumatic conditions and are susceptible to bacterial infections that pose significant challenges for aquaculture production. The indiscriminate use of antibiotics in the past has led to the emergence of multidrug-resistant pathogens and sudden outbreaks of infectious diseases, resulting in serious economic losses. Moreover, the use of expensive chemotherapeutic drugs and antibiotics has negative impacts on aquatic environments. Therefore, it is increasingly important to adopt alternative natural agents, such as probiotics and their metabolites, to enhance healthy fish production. Probiotics are microorganisms that have numerous beneficial effects on their hosts. They are environmentally friendly, non-toxic, and cost-effective. This review specifically focuses on the use of Bacillus sp. as probiotics to promote healthy tilapia production in the aquatic sector, while also examining their interactions with the immune system and gut micro-biota. The information presented in this review can guide future research and promote effective and healthy tilapia culture production.

Taxonomic and functional traits of macroinvertebrate community along fish farming pollution gradient: Taxonomic sufficiency for reliable bioassessment

Taxonomic and functional traits of macroinvertebrate community along fish farming pollution gradient: Taxonomic sufficiency for reliable bioassessment

Bioremediation and microbiome-generating electricity in butter catfish (Ompok bimaculatus) aquaculture wastewater treatment via water fern (Azolla microphylla)

The increasing volume of wastewater from fish farming poses a serious environmental threat. This study investigated a novel treatment method for butter catfish (Ompok bimaculatus) wastewater using a constructed wetland-microbial fuel cell (CW-MFC) integrated with the water fern Azolla microphylla. The system was effectiveness in removing pollutants like electrical conductivity (EC), total dissolved solids (TDS), ammonium, nitrate, nitrite, and phosphate was evaluated. Additionally, the electricity generation capabilities were measured. The CW-MFC system achieved significant removal rates: 67.65% for EC, 61.67% for TDS, 100% for ammonium, 75.00% for nitrate, 81.25% for nitrite, and 70.00% for phosphate. Furthermore, the system generated a maximum open-circuit voltage (OCV) of 690±90 mV, a current density (CD) of 7.29±0.43 mA/m³and a power density (PD) of 0.37±0.04 mW/m³. Analysis of the microbial community revealed a diverse root consortium dominated by bacterial genera including Phreatobacter, Emticicia and Rhodobacter, along with fungal genera such as Strelitziana, Ramularia, Cladosporium,Trichomerium, Cercospora, Erythrobasidium and Fusarium. These findings suggest that CW-MFC systems integrated with A. microphylla offer a promising approach for sustainable and efficient treatment of wastewater from catfish farming while simultaneously generating bioelectricity.

Influence of Biofloc Technology and Continuous Flow Systems on Aquatic Microbiota and Water Quality in Japanese Eel Aquaculture

Biofloc technology (BFT) systems heavily rely on microbiota to mitigate ammonia toxicity and manage essential nutrient cycling. Understanding the diversity and functional role of microbiota within BFT-applied aquaculture systems is crucial for ensuring sustainable operations. Though some studies exist on BFT microbiota, research on microbial differences in Japanese eel aquaculture is still limited, hindering the wider application of BFT systems. In this study, we analyzed the characteristics of water quality factors and microbiota in Japanese eel (Anguilla japonica) breeding water, applying the BFT system. Using a metabarcoding approach, the diversity and community structure of aquatic microbiota were compared between BFT and continuous flow (CF) systems. The pH was significantly higher in CF water, while total ammonia nitrogen (TAN) and nitrite (NO2−-N) was higher in BFT water. Alpha diversity was significantly higher in BFT compared to CF systems, and it was correlated significantly with pH and TAN. In both BFT and CF water, the phyla Proteobacteria and Bacteroidota were found to be the most abundant. In the BFT water, a diverse array of bacterial taxa, including BFT-specific clades, were consistently present, while the microbiota in CF water was more variable and contained fewer specific taxa. In addition, bacterial functions related to nitrate reduction, sulfur compound oxidation, and chitinolysis were significantly more abundant in BFT than in CF systems. These findings highlight differences in water quality and microbiota between aquaculture systems, which can inform future research on the use of BFT for sustainable fish farming.

Evaluating the Presence of Interspecific Hybrids Among Piaractus mesopotamicus, Piaractus brachypomus and Colossoma macropomum in the Upper Paraná River Using Genetic Markers

ABSTRACTFish hybridization is common in aquaculture worldwide, including in Brazil, with cross‐breeding between species of the genera Piaractus and Colossoma taking the lead. However, little is known about the genetic damage caused by hybrids that escape into natural environments. In the upper Paraná River region, hybrid fishes are overproduced; therefore, the use of molecular techniques for their monitoring and identification is necessary. This study aimed to detect the presence of possible hybridization between Piaractus and Colossoma in the upper Paraná River using the molecular markers cytochrome c oxidase subunit 1 (COI) and α‐tropomyosin (TROP). Fragments from 53 fish samples were analysed, and 41 samples were considered hybrids, with 12 confirmed pure, six as Piaractus mesopotamicus (pacu) and six as Piaractus brachypomus (pirapitinga). This is the first record of P. brachypomus, which is an invasive species in this basin, while Colossoma macropomum has not been observed. Molecular markers efficiently detected hybrids in the Ivinhema and Paraná rivers. The results showed a predominance of hybrid specimens from P. mesopotamicus × P. brachypomus. Our study suggests that more restrictions on hybridization and better supervision of fish farms are needed to prevent the escape of hybrids and the consequent ecological and genetic damage to native populations. We warn of the risk of a decline in the population of P. mesopotamicus, as this species is of great importance for fishing and maintaining the ecosystem.

Biomarker responses in fish caged in a rice field during a bifenthrin application

The use of pesticides in integrated rice-fish farming could have an impact on fish health. The present study aimed to evaluate, for the first time, the biological effects of the insecticide bifenthrin on fish (Piaractus mesopotamicus and Hoplosternum littorale) using a caging experiment. Fish were divided into two sites: control (C) and bifenthrin exposure (BF). Two cages (n = 8 fish/cage) per species were placed separately at each site. The BF application (Seizer ®) was carried out with a coastal sprayer according to the BF recommended dose for rice cultivation (0.1 L/ha). After 72 hours, fish were collected, and gills, liver, brain, and muscle were dissected for the analysis of biomarkers of accumulation, oxidative stress, and neurotoxicity. In P. mesopotamicus, the main changes were observed in the muscle, where BF accumulated and induced neurotoxicity (inhibition of cholinesterase activity) and oxidative stress (activation of antioxidant enzymes, decreased glutathione levels, increased lipid peroxidation). The gills and liver also showed changes in some markers of the antioxidant system. In H. littorale, BF exposure induced changes in oxidative stress biomarkers in liver (activation of antioxidant enzymes and lipid peroxidation) and gill tissues (alteration in antioxidant markers). These results show that the use of bifenthrin in rice fields poses a risk to fish farming under current pesticide management practices. Furthermore, its use could affect other species in these agroecosystems, highlighting the need for further studies to assess the ecological and productive consequences in a context of increasing pyrethroid use worldwide.

Single-cell transcriptome profiles and E−64 inhibitor data reveal the essential role of cysteine proteases in the ontogeny of Ichthyophthirius multifiliis

Ichthyophthiriasis (Ich), also known as white spot disease, causes significant economic losses to fish farmers once an outbreak occurs. For fish survival, it is therefore crucial to understand the pathogenic mechanism and find effective prevention methods. In this study, we obtained data for four stages (theront, trophont, protomont and tomont) of Ichthyophthirius multifiliis by single-cell RNA sequencing (scRNA-seq). We found that the invasion-related proteins encoded by highly expressed genes in the theront stage mainly belong to the leishmanolysin family proteins, heat shock proteins, transmembrane proteins and cysteine proteases (CPs). Additionally, the exosome pathway appears to play a significant role in the invasion process of the theront. Since cysteine proteases are expressed at all stages of the I. multifiliis, and five CP-related genes were significantly upregulated at the theront stage of its life cycle — two of which are enriched in the exosome pathway — we incubated I. multifiliis theronts and protomonts with cysteine protease inhibitor (E−64). Our findings revealed that E−64 could kill both stages of the parasite in vitro and affected tomont division and subsequent release. Furthermore, infection experiment showed that E−64 could significantly inhibit the invasion of theronts. Based on our preliminary analysis from the transcriptomic and E−64 experiments, we have confirmed that CPs play a crucial role in I. multifiliis. This research establishes a foundation for future strategies in the prevention and control of Ich.

Smartphone apps pertaining to aquaculture sector in Bangladesh: Current status and future potentials

In recent years, the aquaculture sector in Bangladesh has experienced significant technological advancements, notably the adoption of smartphone applications. This empirical study evaluates the current status of smartphone apps available in the aquaculture industry of the country using data obtained from the internet and field surveys. The study identified 41 smartphone apps currently used in the sector, where 58.53 % are related to pond-based aquaculture, 14.63 % are designed for biofloc system, 4.87 % pertain to cage aquaculture and 4.87 % marketing-aided corporate-related apps, 9.75 % focus on disease and treatment-related, and 7.31 % fall into miscellaneous categories. The “Poultry Animals and Aqua Index (PAAI)" app, which addresses aquaculture pharmaceutical inputs and fish disease treatment guidelines, emerged as the most downloaded app in this domain. Pearson correlation analysis indicated that app size or user ratings did not influence app downloads. The study also found that approximately 57.66 % of fish farmers are aware of these smartphone apps. Private fisheries professionals were the main driving forces behind the use of these apps, accounting for 52 % of the information spread. Despite mixed levels of satisfaction among farmers, about 25 % expressed a positive experience. Most of the farmers (57.66 %) acknowledged the awareness and beneficial impacts of using these apps in aquaculture. This study enhances the understanding of smartphone apps usage in Bangladesh to promote the aquaculture industry, highlighting its potential to promote industry growth, alleviate poverty, and contribute to economic development.

Smart City Aquaculture: AI-Driven Fry Sorting and Identification Model

The development of smart agriculture has become a critical issue for the future of smart cities, with large-scale management of aquaculture posing numerous challenges. Particularly in the fish farming industry, producing single-sex fingerlings (especially male fingerlings) is crucial for enhancing rearing efficiency and could even provide key support in addressing future global food demands. However, traditional methods of manually selecting the gender of broodfish rely heavily on experienced technicians, are labor-intensive and time-consuming, and present significant bottlenecks in improving production efficiency, thus limiting the capacity and sustainable development potential of fish farms. In response to this situation, this study has developed an intelligent identification system based on the You Only Look Once (YOLO) artificial intelligence (AI) model, specifically designed for analyzing secondary sexual characteristics and gender screening in farmed fish. Through this system, farmers can quickly photograph the fish’s cloaca using a mobile phone, and AI technology is then used to perform real-time gender identification. The study involved two phases of training with different sample sets: in the first phase, the AI model was trained on a single batch of images with varying parameter conditions. In the second phase, additional sample data were introduced to improve generalization. The results of the study show that the system achieved an identification accuracy of over 95% even in complex farming environments, significantly reducing the labor costs and physical strain associated with traditional screening operations and greatly improving the production efficiency of breeding facilities. This research not only has the potential to overcome existing technological bottlenecks but also may become an essential tool for smart aquaculture. As the system continues to be refined, it is expected to be applicable across the entire life cycle management of fish, including gender screening during the growth phase, thereby enabling a more efficient production and management model. This not only provides an opportunity for technological upgrades in the aquaculture industry but also promotes the sustainable development of aquaculture. The smart aquaculture solution proposed in this study demonstrates the immense potential of applying AI technology to the aquaculture industry and offers strong support for global food security and the construction of smart cities.

Behavioral, electrocardiographic, and opercular beat recording characterization of tilapia (Oreochromis niloticus) in immersion bath with different concentrations of tricaine (MS-222)

In the world scenario of farmed fish production, tilapia stands out as one of the most cultivated species. In view of animal welfare in fish farming, stressful practices such as biometrics and transportation are minimized by the use of anesthetic agents, with tricaine (MS-222) being among the most commonly used. Despite its extensive use, its anesthetic responses remain a focus of investigation for animal safety. Therefore, the present study aims to evaluate the electrocardiographic and respiratory activity of juvenile Nile tilapia exposed to different concentrations of tricaine. In this study, juvenile Nile tilapia (30.9 ± 5.5 g, n = 99) were subjected to tricaine anesthetic baths at concentrations of 150–250 ppm for behavioral analysis and electrophysiological recordings (electrocardiogram and opercular beating). Our results show that induction and recovery of anesthesia with tricaine in juvenile Nile tilapia was effective for a short-term anesthesia with dose-dependence characteristics. Furthermore, the electrophysiological data reveal a marked decrease in heart rate (28.10–44.08 %) and opercular beating (35.72–59.19 %), depending on the concentration of tricaine used, with reversibility during the recovery period. Therefore, we can infer that the safe utilization window for tricaine varies between 150–250 ppm in juvenile tilapia, emphasizing that its administration should consider the anesthetic plan with monitoring of physiological parameters, especially respiratory ones, which are more easily evidenced.

АРАЛ ҚАЯЗЫНЫҢ (LUCIOBARBUS BRACHYCEPHALUS) ШАБАҚТАРЫН ҚОЛДАН ӨСІРУ ТӘЖІРИБЕСІ

This article presents the results of research to assess the growth of fingerlings of the rare and endangered Aral barbel (Luciobarbus brachycephalus) in fish farms in the Kyzylorda region. The research cover in detail the work on the cultivation of larvae in pond conditions obtained from individuals of barbel caught in the Syrdarya River in the territory of the Kyzylorda region. For research purposes, the characteristics of the pond and the water source in it are given, as well as a description of the tools for conducting control catches. The results of control catches of barbel larvae from the moment they were planted in the pond were analyzed to determine the growth rates of their main biological indicators. The deadlines and intervals of control work are also described in detail. In the conditions of the pond, the obtained results of analyses of indicators of the Fulton fatness index of barbel fry in comparison with representatives of barbel in their natural habitat are presented. During the results of growing barbel fingerlings, it was shown that the average weight of fry in the 2nd decade of September reached 15.1 g, and this indicator gives full opportunity to harvest fish planting material in the conditions of fish farms in the region.

Growth performance and proximate composition of Clarias gariepinus (Burchell, 1822) fingerlings fed varying inclusion levels of ripe banana (Musa Sapientum) peel

The cost of fish feed is of great concern in fish farming. The growth performance and proximate composition of Clarias gariepinus fingerlings fed varying inclusion levels of ripe banana peels as a possibility of replacing soybean as a component of the fish feed were evaluated for a period of 12 weeks. 250 C. gariepinus fingerlings were acclimated for 2 weeks and fed to satiation morning and evening. Five isocaloric and nitrogenous diets were prepared from ripe banana peel thus: 0% (Control), 25% (T25), 50% (T50), 75% (T75) and 100% (T100) inclusion levels to replace equal weights of soybean, respectively. Some growth parameters such as standard length (SL), total length (TL) and weight were determined on weekly basis. The proximate compositions of the fish in each treatment and control were determined at the end of the experiment. The data generated were subjected to one way analysis of variance and considered significant at P≤0.05. From the results; the weight, SL and TL mean values measured in the control were significantly higher than other treatments in most of the weeks of the experiment. The highest weight in the control was 52.43±10.80g while the highest amongst other treatments was 30.67±6.69g obtained in T75 at the end of the 12 weeks. The ash content, crude fibre and fat contents were mostly significantly in T75 and T100. The highest moisture content (12.88±0.74%) was also obtained in T100. The crude protein content was significantly higher in the control than other treatments with 68.69±0.35% at the end of the 12th week. The results of this research has shown that banana peel can be included up to 75% level of inclusion as possible replacement for soybean in fish meal production and therefore, capable of reducing the cost of fish production incurred by farmer. For optimal performance, the crude protein content should be improved upon by inclusion of other cheap protein sources.

Genomic selection for individual feed efficiency in the European seabass: Response to selection on efficiency, commercial traits and sex

Feed efficiency is a key factor in the sustainability of fish farming. Improving feed efficiency not only results in cost savings, but also helps to reduce the environmental footprint associated with feed production and to mitigate competition for feed resources. However, improving feed efficiency through genetic selection poses challenges, mainly due to the difficulty of accurately estimating it in a large population, especially under conventional rearing conditions. In a previous study, a methodology was developed to estimate the individual feed efficiency of sea bass in separate tanks under controlled feeding regimes during the juvenile phase. This approach allowed precise measurement of growth, feed intake and individual feed conversion ratio (iFCR) of each fish. Daily growth rate (iDGC) was found to be highly heritable (h2 = 0.75), and a reliable predictor of iFCR under restricted feeding conditions. In the present study, we aim to demonstrate the response to selection on feed efficiency, commercial traits and sex.From a cohort of 399 sea bass with known iDGC and genotyped for 1110 SNP markers, we selected 27 future efficient parents (Eff+), 35 intermediate parents (Eff0) and 29 inefficient parents (Eff-) by genomic selection (GBLUP). Three years later, 3 groups of offspring were produced from 9 Eff + parents, 13 Eff0 parents and 19 Eff- parents. Performances in individual aquaria (iDGC, iFCR) were assessed for 259 of them, as well as group feed efficiency (gFCR) from 142 g. At 240 g, the fish were slaughtered to assess processing traits.The results showed that the Eff + group had superior efficiency (iFCR and iDGC) and better adaptability to tank conditions compared to the other groups. In the group evaluation phase, significant differences in feed efficiency were observed between Eff- (gFCR = 1.83) and Eff + (gFCR = 1.61) (p < 0.001), with Eff0 being intermediate. In addition, Eff + fish were larger (266 g, 27.4 cm) and leaner with lower Fulton K values compared to Eff0 (234 g, 26.1 cm) and Eff- (223 g, 25.5 cm). Although there were no differences in fillet yield, Eff + had a slightly higher viscerosomatic index. There was also a higher proportion of females in the Eff- (57.1 %) and Eff0 (51.6 %) groups compared to Eff + (43.9 %).In conclusion, selection for feed efficiency in individual tanks is an effective strategy for improving the performance of sea bass, resulting in significant improvements with a marked effect on growth rates. Despite a slight increase in the viscerosomatic index, fillet yield was not significantly affected.

Correlation and regression analysis of unionised ammonia ions, NH3and pH in ornamental fish aquatic environment

Assessing ammonia in water is very important for fish farmers as it is one of the pollutants that may affect the water quality. In water, ammonia can be found either in the form of unionised ammonia NH3 or ionised ammonia NH+4, which contribute to a total ammonia nitrogen (TAN). In assessing the ammonia toxicity, NH3 provides a more accurate measure of toxicity and needs to be monitored consistently, rather than relying solely on TAN. However, the method of measuring NH3 in water can be complex and challenging. Therefore, the ability to determine the correlation between NH3 and other parameter which is easier to be measured (such as pH) is crucial to enable the estimation of NH3. This study was conducted to determine the correlation between NH3 and pH based on the data collected from Redgold Aquatics ornamental fishponds located in Sik, Kedah. The pH was assessed by a commercial measuring device, while the NH3 was calculated using an appropriate mathematical equation that requires the data of pH, TAN, and temperature. The correlation and regression analysis were conducted via the IBM SPSS tool and Microsoft Excel. The result shows that NH3 and pH are highly correlated with regression equation of NH3 = 0.01pH – 0.07. In addition, factors that may affect the total ammonia value have been discussed thoroughly in this work. The analysis of these water quality parameters may assist farmers in estimating the toxic ammonia, NH3 from the known water pH.

Effect of Rice–Carp Coculture on Phytoplankton and Microzooplankton Community Composition in Paddy Water during Different Rice Growth Stages

Integrated rice–fish farming, an agricultural practice that combines cultivating rice and breeding fish in the same field, has attracted widespread attention. However, there is limited research on how the rice–carp coculture impacts the community structure of phytoplankton and microzooplankton in paddy water. This study employed eDNA metabarcoding sequencing to analyze the composition of phytoplankton and microzooplankton in a rice monoculture system (RM) and a rice–carp coculture system (RF). Following annotation, we identified 9 phyla, 89 families, 275 genera, and 249 species of phytoplankton, along with 20 phyla (or subphyla and classes), 85 families, 222 genera, and 179 species of microzooplankton. The alpha diversity indices revealed significantly higher richness, diversity, and evenness in the RF group compared to the RM group during grain-filling stage. Principal coordinates analysis (PCoA) demonstrated notable differences in the phytoplankton and microzooplankton compositions between the two groups across various rice growth stages. Composition analysis showed that rice–carp coculture increased the relative abundance of dominant phytoplankton phyla such as Bacillariophyta, Chrysophyta, and Euglenophyta while decreasing that of Cryptophyta. In microzooplankton, the coculture resulted in an increased abundance of Intramacronucleata (subphylum) and a decrease in Conoidasida (class). In conclusion, the rice–carp coculture enhances the diversity of plankton, particularly during the grain-filling stage, and simultaneously alters the composition and abundance of dominant plankton species in the paddy water. These findings enhance understanding of the broader impacts of integrated rice–carp farming on agricultural ecosystems, emphasizing alterations in the diversity and composition of aquatic microorganisms

EVALUATION OF THE CLINICAL SAFETY OF ORAL CURCUMIN TREATMENT IN NILE TILAPIA (Oreochromis niloticus)

Curcumin is considered a multifunctional feed additive, with immunostimulant properties. Given this potential, it is crucial to deepen studies on the safety of substances like curcumin in fish, ensuring its safe and effective use for sustainable aquaculture. In this context, the present study aimed to evaluate the clinical safety of curcumin in tilapia, administered orally via feed, through hematological and biochemical analyses. A total of 63 fish (±100g) from a commercial fish farm, Sales de Oliveira/SP, were randomly distributed in 9 tanks of 100 L each, supplied with chlorine-free water. The treatments were: T0 (control, without curcumin), T1 and T2 (treated with 100 and 400 mg/kg of curcumin, respectively). Seven fish were sampled per treatment at four time points: 4, 8, and 12 days post-treatment (DPT), along with an additional recovery period up to day 16. Blood samples were collected for hematological and biochemical analysis, along with somatic evaluation of the organs. The results showed a significant increase in the number of erythrocytes and hematocrit in tilapia treated with curcumin, particularly at doses of 400 mg/kg at 12DPT and 100 mg/kg at 16DPT. There were no significant differences in the leukogram, total protein levels, or somatic index of the organs between the groups. Serum creatinine levels temporarily decreased, returning to baseline levels, and a significant peak in glucose levels was observed at 16DPT, especially at the 400 mg/kg dose. Further studies are needed to elucidate the mechanisms involved and confirm the clinical safety of curcumin over longer periods.

Analysis of the dynamics of production and foreign trade of fish products in Russia. Prospects for the development of the industry in the context of economic sanctions

Purpose: based on long-term data on the dynamics of fish catches and foreign trade in fish products, as well as international comparisons of world fishing powers, analyze the prospects for the development of the domestic fishing industry in the new economic conditions of sanctions confrontation with the countries of the collective West.Method: used such methods of general scientific knowledge as analysis and synthesis, as well as comparisons, tabular and graphical methods.Novelty: a detailed assessment of the factors affecting the growth of domestic fishing and fish farming, including the development of the domestic fishing fleet, was made. The prospects for expanding the sale of fish products on world markets, including on the basis of data on current and prospective consumption in different regions of the world, were considered.Results: the study analyzed a number of sources, including FAOSTAT and Rosstat commodity resource balances, in terms of production, consumption and cross-border trade in fish products. It has been established that after 2014 own consumption and imports are declining, while exports, on the contrary, are gradually increasing. Thus, the main driver of production growth in the industry is expansion to foreign markets. In the context of strengthening anti-Russian sanctions policy, it is necessary to diversify the sales markets for Russian fish products, however, an outdated production base is a significant limitation for the development of the industry.

Technology of the fish abundance accounting in fish farming cages using hydroacoustic and software tools

The purpose of the work: improvement of methods of fish number accounting in growing cages and reservoirs of fish farms using hydroacoustic tools and information technologies.Methods used: solving the problem of non-contact (non-invasive) measurement of the number of fish in cages using the hydroacoustic echo integration method. Investigation of the reflective properties of fish using a calibrated scientific echo sounder with a split beam. Carrying out measurements with different numbers of fish in cage. Identification and analysis of factors affecting the accuracy of the echo integration estimation of the number of fishes in cage.Novelty: the elements of novelty are the use of a scientific echo sounder with vertically oriented antenna and split beam to estimate the number of fishes in cages, the algorithm for calculating the number of fishes in cages by the echo integration method, the results of the study of reflective properties of Amur carp and identified optimal measurement conditions that allow hydroacoustic estimates of number with maximum accuracy.Results: the dependences of target strength on the linear size of Amur carp are obtained. An algorithmic scheme for calculating the number of fishes in cages by the hydroacoustic echo integration method has been developed. Experiments were carried out with different numbers of fish in the cage. It is established that the main factors affecting the accuracy of the population estimate are the number of individuals in the cage and the daily distribution of fish. Measurements at night and at concentrations above the threshold (50 pcs./m2) can significantly bring the estimated and true numbers of fish in the cage closer and reduce the variability of density estimates.Practical significance: solving the problem of remote measurement of the fish number in growing cages will allow farmers to optimize feed needs, which, in turn, will ensure rapid growth of fish without overfilling it and not polluting the reservoir.

Integrated assessment of the economic efficiency of commercial fish farming

The purpose of the work: Conduct an integrated assessment of the economic efficiency of commercial fish farming.Materials and methods: The information base of the study was made up of statistical and operational materials on commercial fish farming of the Central Federal District of Russia (CFD) for 2015–2021. The main research methods were the monographic method, the method of analyzing the production and economic activities of the Central Federal District through scientific approaches, as well as the method of interpreting the results of the study.The result based on the developed methodology, an analysis of the economic efficiency of commercial fish farming in the Central Federal District of Russia (CFD) was carried out on the basis of the use of a complex (integral) indicator, which allowed identifying the main factors affecting the level and dynamics of the economic efficiency of commercial fish farming in the CFD. The degree of influence of particular indicators on the economic efficiency of production is shown — labor productivity, material output, capital.The practical significance it is possible to use a complex indicator in the analysis of production and economic activity, which allows determining reserves for improving the efficiency of using production resources — living and past labor. The complex indicator can also be used in the development of current options and long-term production plans, followed by the selection of the most effective option.

Effectiveness of Anchor Borrowers’ Program on Fish Farming in Osun State, Nigeria

Effectiveness of Anchor Borrowers’ Program on Fish Farming in Osun State, Nigeria