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This article provides a brief analysis of the water resources of Kalmykia in relation to the history of the fishing industry in the region in the lower reaches of the Volga and mainly in the Caspian region. Aquatic biological resources, especially fish, play a significant social and economic role among all the natural resources of our country. In the modern period, the fishing industry still plays a huge role in the development of the national economy of the Russian Federation. The GDP of Russia and the GRP of the subjects of the Federation, food security of the country, social well-being of our citizens depend on how the Russian fishing industry will develop as a whole and in its regions, since fish products are an important and necessary component of healthy nutrition and human life. The purpose of the article is to show the complex process of the emergence and development of the fishing industry of the Kalmyk Autonomous Region using the example of Kalmykrybtrest in the 1920s. In the modern period of development of the country’s market economy, the study of the historical experience of the emergence and development of the fishing industry of Kalmykia in the context of the new economic policy is very relevant from the point of view of the organization of the fishing business and management methods. The use of historical and problemchronological methods in the work allowed us to highlight the history of the formation of the fishing industry of Kalmykia in the first decade of Soviet power, to show the features of its development. The article is based on various sources, mainly on archival materials and published works on the history of the fishing industry of the Kalmyk Autonomous Region. The focus of the study is the study and analysis of party and state decisions of the center, the Kalmyk Autonomous Region and the Astrakhan province in the 1920s, aimed at the territorial definition of fisheries and the search for optimal ways of developing the fishing industry of the steppe region. One of the timely and correct decisions of the federal and regional authorities was the organization in 1923 of the Kalmrybaktrest, whose activities are thoroughly discussed in this article.

The environmental regulation of continental fish farming in Brazil is closely linked to land occupation and use. Areas used for this activity are mostly located in permanent preservation areas (PPA), close to rivers and springs, demonstrating the necessity of regulating this activity for its compliance with public policy. Santa Catarina is a leading state in fish farming and one of the first to regulate the use of PPAs. The feasibility of a proposal for environmental compensation to regularize the use of PPAs in Santa Catarina for fish farming; was therefore, assessed. The results showed that 74% of the fish farms analyzed need to regularize the occupation of production structures in PPAs. Regarding the proposed index of compensation for use in PPAs, the environmental compensation factor (ECF), through evaluation of the individual maps and subsequent integrated evaluation, all the fish farms identified with environmental liabilities in occupation had ratios of 1:2 and 1:3, and this index is a viable alternative for environmental regularization of the activity. It was further proposed that ECF be applied to small fish farms of up to four fiscal modules and that they have a standard minimum occupancy profile in relation to the total area of the property, as assessed in the present study. [ABSTRACT FROM AUTHOR]

Introduction: Hypoxia is defined as a critically low-oxygen condition of water, which, if prolonged, can be harmful to fish and many other aquatic species. In the context of ocean salmon fish farming, early detection of hypoxia events is critical for farm managers to mitigate these events to reduce fish stress, however in complex natural systems accurate forecasting tools are limited. The goal of this research is to use a machine learning approach to forecast oxygen concentration and predict hypoxia events in marine net-pen salmon farms. Methods: The developed model is based on gradient boosting and works in two stages. First, we apply auto-regression to build a forecasting model that predicts oxygen concentration levels within a cage. We take a global forecasting approach by building a model using the historical data provided by sensors at several marine fish farms located in eastern Canada. Then, the forecasts are transformed into binary probabilities that indicate the likelihood of a low-oxygen event. We leverage the cumulative distribution function to compute these probabilities. Results and discussion: We tested our model in a case study that included several cages across 14 fish farms. The experiments suggest that the model can detect future hypoxic events with a commercially acceptable false alarm rate. The resulting probabilistic predictions and oxygen concentration forecasts can help salmon farmers to prioritize resources, and reduce harm to crops. [ABSTRACT FROM AUTHOR]

This research evaluated the importance of establishing an integrated sprinkler irrigation design connected to fish farm ponds in order to achieve environmental and financial benefits. To achieve the aim of the study, two field experiments were conducted at a private farm in the Nubaria area of Beheira Governorate during the 2022 and 2023 seasons to quantify all the benefits from using fish water effluent (FWE) in irrigation. The obtained results indicated that the effluent could represent a good source of irrigation and bio-fertilization. The yield of tomato was higher when using FWE for irrigation compared with using groundwater for irrigation (IW). This was due to the additional amounts of dissolved bio-nitrogen along with other nutrients present in the FWE. The proportion of dissolved nitrogen added by using FWE was 22.3 kg nitrogen per hectare in 2022 and 24.6 kg nitrogen per hectare in 2023, in addition to some other major elements such as phosphorus and potassium, which are also among the main nutrients needed by crops. It has also been noticed that the fertility of the sandy soil increased with the use of FWE for irrigation. One of the most important results was the possibility of reducing the addition of nitrogen mineral fertilizers by 25%, thus saving on N fertilizers when growing tomato. In addition to the vitality of the FWE and its macro- and microelements, algae, microorganisms, and other organic materials, the use of this type of water as an alternative source for irrigation, along with the reduction in the amount of added mineral fertilizers, will reduce the degree of groundwater contamination with mineral fertilizers and increase the income of farmers. It was also observed that the air temperature decreased during the growing season when compared with the temperature of uncultivated surrounding areas. [ABSTRACT FROM AUTHOR]

ABSTRACT: The environmental regulation of continental fish farming in Brazil is closely linked to land occupation and use. Areas used for this activity are mostly located in permanent preservation areas (PPA), close to rivers and springs, demonstrating the necessity of regulating this activity for its compliance with public policy. Santa Catarina is a leading state in fish farming and one of the first to regulate the use of PPAs. The feasibility of a proposal for environmental compensation to regularize the use of PPAs in Santa Catarina for fish farming; was therefore, assessed. The results showed that 74% of the fish farms analyzed need to regularize the occupation of production structures in PPAs. Regarding the proposed index of compensation for use in PPAs, the environmental compensation factor (ECF), through evaluation of the individual maps and subsequent integrated evaluation, all the fish farms identified with environmental liabilities in occupation had ratios of 1:2 and 1:3, and this index is a viable alternative for environmental regularization of the activity. It was further proposed that ECF be applied to small fish farms of up to four fiscal modules and that they have a standard minimum occupancy profile in relation to the total area of the property, as assessed in the present study.

Abstract This study was divided into two parts. The first part involved the isolation, and detection of the prevalence and antimicrobial resistance profile of Aeromonas hydrophila, Pseudomonas aeruginosa, and Vibrio species from Nile tilapia fish and marine aquatic water. One hundred freshly dead Nile tilapia fish were collected from freshwater aquaculture fish farms located in Al-Abbassah district, Sharkia Governorate, and 100 samples of marine aquatic water were collected from fish farms in Port Said. The second part of the study focused on determining the in vitro inhibitory effect of dual-combination of AgNPs-H2O2 on bacterial growth and its down regulatory effect on crucial virulence factors using RT-PCR. The highest levels of A. hydrophila and P. aeruginosa were detected in 43%, and 34% of Nile tilapia fish samples, respectively. Meanwhile, the highest level of Vibrio species was found in 37% of marine water samples. Additionally, most of the isolated A. hydrophila, P. aeruginosa and Vibrio species exhibited a multi-drug resistance profile. The MIC and MBC results indicated a bactericidal effect of AgNPs-H2O2. Furthermore, a transcriptional modulation effect of AgNPs-H2O2 on the virulence-associated genes resulted in a significant down-regulation of aerA, exoU, and trh genes in A. hydrophila, P. aeruginosa, and Vibrio spp., respectively. The findings of this study suggest the effectiveness of AgNPs-H2O2 against drug resistant pathogens related to aquaculture.

The consumption of fisheries and aquaculture products has been increasing in recent decades, and it is necessary to strike a balance between production and sustainability in aquaculture; this is essential homework to support the demand for human food. This study aimed to investigate the sensory and nutritional characteristics of a sausage made from the fillet of the native fish Old Blue (Andinoacara rivulatus) to stimulate the local economy. A multifactorial A*B*C design was used, with Factor A being rearing systems (wild and farmed), Factor B being types of protein (quinoa meal and soybean meal), and Factor C being lipids of animal (pork fat) and vegetable (sunflower oil) origin. Highly significant differences were observed in all formulas, according to Tukey (p < 0.05). The highest protein percentage was with soybean flour at 11.24%, while quinoa flour had 10.80% of the product. In sensory characteristics, the best attributes were for texture in the mouth with a hedonic scale from 0 to 5, with 4.2 firmness being mostly acceptable, odor at 4.5, the aromatic attribute with the highest and best value, and color was the clearest at 4.3 acceptability. The flavor was 4.3, mostly more pleasant according to the tasters. The yield of farmed fillets was 23.16% compared to wild 13.89%, and the balance of sausage yield was 393 g with a yield of 76.33% of the total weight. Microbiological analysis of the sausage with the native species showed the absence of pathogenic microorganisms. A commercial shelf life of 30 days was also established for the sausage, demonstrating an added value through this processing, allowing its exploitation in areas further away from the fishing sites and, thus, a greater possibility of social development in the area. [ABSTRACT FROM AUTHOR]

This study was divided into two parts. The first part involved the isolation, and detection of the prevalence and antimicrobial resistance profile of Aeromonas hydrophila, Pseudomonas aeruginosa, and Vibrio species from Nile tilapia fish and marine aquatic water. One hundred freshly dead Nile tilapia fish were collected from freshwater aquaculture fish farms located in Al-Abbassah district, Sharkia Governorate, and 100 samples of marine aquatic water were collected from fish farms in Port Said. The second part of the study focused on determining the in vitro inhibitory effect of dual-combination of AgNPs-H2O2 on bacterial growth and its down regulatory effect on crucial virulence factors using RT-PCR. The highest levels of A. hydrophila and P. aeruginosa were detected in 43%, and 34% of Nile tilapia fish samples, respectively. Meanwhile, the highest level of Vibrio species was found in 37% of marine water samples. Additionally, most of the isolated A. hydrophila, P. aeruginosa and Vibrio species exhibited a multi-drug resistance profile. The MIC and MBC results indicated a bactericidal effect of AgNPs-H2O2. Furthermore, a transcriptional modulation effect of AgNPs-H2O2 on the virulence-associated genes resulted in a significant down-regulation of aerA, exoU, and trh genes in A. hydrophila, P. aeruginosa, and Vibrio spp., respectively. The findings of this study suggest the effectiveness of AgNPs-H2O2 against drug resistant pathogens related to aquaculture. [ABSTRACT FROM AUTHOR]

The innovative study "Fuzzy Logic Empowered NetWatch: Revolutionizing Aquaculture with IoT-based Intelligent Monitoring and Management in Bangladesh" is a step towards the dawn of a new era in fish farming techniques that emphasize accuracy and efficiency. Using fuzzy logic controllers in the NetWatch system, stakeholders involved in aquaculture can access a degree of intelligence and adaptability that is not possible with standard management techniques. Fuzzy logic techniques are included in NetWatch, allowing it to make intelligent judgments based on the intricate and frequently unpredictable nature of aquaculture systems, in addition to monitoring and controlling environmental parameters and water quality. Because of its dynamic adaptability, the system can mitigate risks and optimize results in real time while successfully responding to changing situations. Furthermore, NetWatch offers a comprehensive picture of the aquaculture ecosystem by combining pond-specific data with more general environmental insights, facilitating better-informed macro and micro decision-making. With this thorough knowledge, fish farmers can allocate resources more efficiently, reduce waste, and sustainably increase productivity. Moreover, Fuzzy Logic Empowered NetWatch's revolutionary potential offers opportunities for the aquaculture industry, transcending the boundaries of individual fish ponds. Bangladesh can establish itself as a global leader in sustainable aquaculture methods and set new benchmarks for production, efficiency, and environmental stewardship using IoT-based intelligent monitoring and management. Fuzzy Logic Empowered NetWatch catalyzes a systemic shift in how we approach aquaculture management rather than merely technology. Bangladesh may achieve previously unattainable levels of sustainability and productivity by utilizing fuzzy logic and the Internet of Things. This would guarantee a better future for the country's aquaculture sector and the communities it serves. [ABSTRACT FROM AUTHOR]

IntroductionHypoxia is defined as a critically low-oxygen condition of water, which, if prolonged, can be harmful to fish and many other aquatic species. In the context of ocean salmon fish farming, early detection of hypoxia events is critical for farm managers to mitigate these events to reduce fish stress, however in complex natural systems accurate forecasting tools are limited. The goal of this research is to use a machine learning approach to forecast oxygen concentration and predict hypoxia events in marine net-pen salmon farms.MethodsThe developed model is based on gradient boosting and works in two stages. First, we apply auto-regression to build a forecasting model that predicts oxygen concentration levels within a cage. We take a global forecasting approach by building a model using the historical data provided by sensors at several marine fish farms located in eastern Canada. Then, the forecasts are transformed into binary probabilities that indicate the likelihood of a low-oxygen event. We leverage the cumulative distribution function to compute these probabilities.Results and discussionWe tested our model in a case study that included several cages across 14 fish farms. The experiments suggest that the model can detect future hypoxic events with a commercially acceptable false alarm rate. The resulting probabilistic predictions and oxygen concentration forecasts can help salmon farmers to prioritize resources, and reduce harm to crops.

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In Brazil, studies evaluating the concentration of trace metals in fish farms are scarce. Therefore, studies investigating the presence and levels of these metals in aquatic biota, particularly in fish tissues, are crucial for developing appropriate strategies to mitigate the impact of possible toxic metals. Herein, we investigated the levels of trace metals (Cr, Mn, Co, Ni, Cu, Zn, Al, Ag, Cd, Pb, Fe, Na, Mg, Ca, K, and Ba) in water, feed, and sediment, as well as the bioconcentration and bioaccumulation factors in tambaqui muscles (Colossoma macropomum). For this purpose, eight commercial fish farms, which are also engaged in other agricultural activities, were selected. Fe, Zn, Mg, and Cr concentration in tambaqui muscles exceeded the limits set by the Brazilian regulations for daily consumption by adults. Mn, Zn, Al, Pb, Fe, Na, Cu, Co, Ag, Cd, and Ba levels were substantially higher in the liver tissue of tambaquis than those in the muscle tissue. The most prevalent metals found in the feed were Ca, K, Na, Mg, and Fe. However, the levels of Cr and Cd in the sediment, as well as Pb, Mn, Cu, and Fe in the water, exceeded the maximum limits allowed by the Brazilian legislation. The highest bioconcentration factors were observed for the metals, Na, Zn, and K, with concentrations up to 4.74, 12.61, and 72.08 times, respectively, higher in tambaqui muscle compared to those in water. The bioaccumulation factors for Ca, Zn, Mg, Na, and K were 2.90, 6.96, 21.21, 212.33, and 492.02 times, respectively, higher in the muscle tissue than those in the sediment values in fishponds across all fish farms. Therefore, our findings suggest that tambaquis have a remarkable ability to bioaccumulate trace metals, particularly the essential ones, and can be categorized as a bioindicator species for environmental quality. Furthermore, we observed that, although water exhibits the highest prevalence and diversity of elements above the values recommended by the Brazilian legislation, sediment is the primary source of trace metal contamination for tambaquis. [ABSTRACT FROM AUTHOR]

In this work, we extracted chitosan from marine amphipods associated with aquaculture facilities and tested its use in crop protection. The obtained chitosan was 2.5 ± 0.3% of initial ground amphipod dry weight. The chemical nature of chitosan from amphipod extracts was confirmed via Raman scattering spectroscopy and Fourier transform infrared spectroscopy (FTIR). This chitosan showed an 85.7–84.3% deacetylation degree. Chitosan from biofouling amphipods at 1 mg·mL−1 virtually arrested conidia germination (ca. sixfold reduction from controls) of the banana wilt pathogenic fungus Fusarium oxysporum f. sp cubense Tropical Race 4 (FocTR4). This concentration reduced (ca. twofold) the conidia germination of the biocontrol fungus Pochonia chlamydosporia (Pc123). Chitosan from amphipods at low concentrations (0.01 mg·mL−1) still reduced FocTR4 germination but did not affect Pc123. This is the first time that chitosan is obtained from biofouling amphipods. This new chitosan valorizes aquaculture residues and has potential for biomanaging the diseases of food security crops such as bananas. [ABSTRACT FROM AUTHOR]

The main aim of the Egyptian government is not only to increase tilapia fish production, but also to improve the quality of the fish produced. Contaminated water causes damage to farmed fish and is also considered an important factor affecting the fish quality. To avoid losses in fish farms, it is critical to obtain information on the microbial load. This research aimed to study the microbial load in four fish farms in the governorates of Kafr El-Sheikh and El-Faiyum (two farms in each governorate), in Egypt. Water and fish samples were collected at various locations within each farm pond for two seasons (autumn and spring) to assess the microbiological characteristics. Total coliform count of aquaculture water samples was the highest mean count of 3.93x103±1.81x10³ CFU/ml in farm (3) of El-Faiyum. However, Clostridium counts were highest in farm (2) of Kafr El-Sheikh at 1.85x10² ±1.76x10² in autumn of 2021. Total coliform count (1.196x10³±8.38x10²) was the highest in farm (1) of Kafr El-Sheikh in spring 2022. Also, Salmonella spp. was only detected in farm (2) of Kafr El-Sheikh in autumn 2021, but in spring 2022 it was positive in farm (3) of El-Faiyum. Nevertheless, Listeria spp. was not detected in the aquaculture water samples examined. In addition, Salmonella spp. was detected in farm (1) of Kafr El-Sheikh and in farms (3 and 4) of El-Faiyum in spring 2022. It was concluded that the presence of pathogenic bacteria such as Staphylococcus aureus, Salmonella and Clostridium in fish samples in some farms in Kafr El-Sheikh and El-Faiyum may contribute to foodborne illness. So that, the microbiological criteria are recommended to be applied as guidelines to develop additional control programs in fish farms. This can help in the pollution control of the agricultural drainage water that is used in aquaculture; consequently, prevent the growth and toxin production by pathogens [ABSTRACT FROM AUTHOR]

This research evaluated the importance of establishing an integrated sprinkler irrigation design connected to fish farm ponds in order to achieve environmental and financial benefits. To achieve the aim of the study, two field experiments were conducted at a private farm in the Nubaria area of Beheira Governorate during the 2022 and 2023 seasons to quantify all the benefits from using fish water effluent (FWE) in irrigation. The obtained results indicated that the effluent could represent a good source of irrigation and bio-fertilization. The yield of tomato was higher when using FWE for irrigation compared with using groundwater for irrigation (IW). This was due to the additional amounts of dissolved bio-nitrogen along with other nutrients present in the FWE. The proportion of dissolved nitrogen added by using FWE was 22.3 kg nitrogen per hectare in 2022 and 24.6 kg nitrogen per hectare in 2023, in addition to some other major elements such as phosphorus and potassium, which are also among the main nutrients needed by crops. It has also been noticed that the fertility of the sandy soil increased with the use of FWE for irrigation. One of the most important results was the possibility of reducing the addition of nitrogen mineral fertilizers by 25%, thus saving on N fertilizers when growing tomato. In addition to the vitality of the FWE and its macro- and microelements, algae, microorganisms, and other organic materials, the use of this type of water as an alternative source for irrigation, along with the reduction in the amount of added mineral fertilizers, will reduce the degree of groundwater contamination with mineral fertilizers and increase the income of farmers. It was also observed that the air temperature decreased during the growing season when compared with the temperature of uncultivated surrounding areas.

The goal of this study is to discover the genetic diversity of twelve Escherichia coli isolates harbor virulence genes (Stx1 and Stx2) isolated from farm fish and local market fish in different locations of Nineveh Governorate using Enterobacterial Repetitive Intergenic Consensus (ERIC-PCR) technique in the time span November, 2021 - January, 2022. The source of contamination was found depending on the fingerprint analysis of the repetitive polymerase chain reaction among the genes of the intestinal micro-organism ERIC-PCR for every isolate. The results show that there are similarities among the isolates and it ranged about 51%-100%. The isolates are divided into 7 genotypes, based primarily on a 90% similarity threshold 1 to 7, with the most offspring being inside genotype 1, since genotype 1 used to be the biggest team containing four isolates. Then, two isolates are grouped under genotypes 3 and 5. In contrast, genotype 2, 4, 6 and 7 have only one isolate. By virtue of genetic variations in the location, there was once an excessive clonal dispersion of most E. coli strains. In addition, the study shows genetic differences in E. coli in 83.3%, (10/12) of the isolates, in the different geographical locations of Mosul city. The E. coli isolates were classified into some groups: first, different genetic grouping, different geographical locations, same genotype; second, different genetic grouping, same geographical locations, different genotypes.

The current study aims to detect the presence of some virulence genes of Escherichia (E.) coli in fish. 46 strains of E. coli were previously isolated from 153 fish samples, including 28 and 18 isolates of E. coli from local markets and fish farms, respectively, in Nineveh Governorate from November 2021 to January 2022. The study results show that all isolates of E. coli possessed the uidA gene with a molecular weight of 623 bp. In addition, they show that 88.9% (16/18) isolates from farmed fish samples possessed the Stx1 gene with a molecular weight of 347 bp, while 72.2% (13/18) of them carried the Stx2 gene with a molecular weight of 589 bp. Also, the study unveils that 89.3 % (25/28) isolated from the market fish samples possessed the Stx1 gene with a molecular weight of 347 bp, and 85.7% (24/28) isolates carried the Stx2 gene with a molecular weight of 589 bp. The rfb gene is detected in this study, neither in farm fish nor in the samples from the local fish markets using the PCR technique. Likewise, it shows that E. coli isolated from fish possessed the Stx1 and Stx2 genes, major causative agents of food poisoning for consumers. Finally, the study gives important information about the application of health conditions on fish farms and fish markets to prevent contamination and reduce infections by foodborne pathogens that cause food poisoning in humans.

The consumption of fisheries and aquaculture products has been increasing in recent decades, and it is necessary to strike a balance between production and sustainability in aquaculture; this is essential homework to support the demand for human food. This study aimed to investigate the sensory and nutritional characteristics of a sausage made from the fillet of the native fish Old Blue (Andinoacara rivulatus) to stimulate the local economy. A multifactorial A*B*C design was used, with Factor A being rearing systems (wild and farmed), Factor B being types of protein (quinoa meal and soybean meal), and Factor C being lipids of animal (pork fat) and vegetable (sunflower oil) origin. Highly significant differences were observed in all formulas, according to Tukey (p < 0.05). The highest protein percentage was with soybean flour at 11.24%, while quinoa flour had 10.80% of the product. In sensory characteristics, the best attributes were for texture in the mouth with a hedonic scale from 0 to 5, with 4.2 firmness being mostly acceptable, odor at 4.5, the aromatic attribute with the highest and best value, and color was the clearest at 4.3 acceptability. The flavor was 4.3, mostly more pleasant according to the tasters. The yield of farmed fillets was 23.16% compared to wild 13.89%, and the balance of sausage yield was 393 g with a yield of 76.33% of the total weight. Microbiological analysis of the sausage with the native species showed the absence of pathogenic microorganisms. A commercial shelf life of 30 days was also established for the sausage, demonstrating an added value through this processing, allowing its exploitation in areas further away from the fishing sites and, thus, a greater possibility of social development in the area.

Within the genus Carassius Jarocki, 1822, the crucian carp (C. carassius L., 1758) occurs naturally in the northern part of Middle Danube Basin (Austria, Morava, Slovakia). This species has the least concern status in this region, but observations in the last decades suggest that it is very close to extinction here. The distribution of crucian carp is limited to a small number of vanishing lentic habitats (oxbow lakes, marshlands). These biotopes are in the last stage of succession due to the drying up of the landscape and a reduction in the creation of new natural alluvial habitats. The non-native cyprinid, C. gibelio (Bloch, 1782), known as gibel carp and Prussian carp, has gradually become eudominant in a wide spectrum of habitats/biotopes since the 1960s Several biological adaptations of non-native species are generally considered the strong basis for the mass spreading in the invaded area. The other side of the expansion of non-native C. gibelio is affected by anthropic activities associated with fish farming, translocation and stocking the fish in open water ecosystems. In this study, we analysed historical scientific data on the distribution of Carassius spp. published from the 19th century to the present from the mentioned areas. The results suggest that the number of records of invasive C. gibelio has gradually increase in rivers, regulated channels and creeks, which could be considered as natural pathways of spreading. However, the presence of invasive C. gibelio in artificial biotopes (fishponds, reservoirs) is continuous from the 1960s. In the area mentioned, the artificial biotopes are managed by national fisheries associations and relate to the historical way of farming in Central and Eastern European countries. To show the current state of the fishing grounds of the Slovak Angling Association, we a created the distribution map based on the Carassius spp. catches recorded in last two decades. [ABSTRACT FROM AUTHOR]

In this study, a shoal of bull rays, Aetomylaeus bovinus (E. Geoffroy Saint-Hilaire, 1817), around a sea-cage fish farm in Iskenderun Bay, Turkey is reported. Such an aggregation is probably due to ontogenetic shift but may also be a factor of reproductive process as some pregnant females were observed. The number of individuals recorded, in all more than 25, shows that the species is still present in the area but needs a conservation plan due to its k-selected life-histories and potential for extinction.

Farming seabass (Dicentrarchus labrax) is an essential activity in the Mediterranean basin including the Aegean Sea. The main seabass producer is Turkey accounting for 155,151 tons of production in 2021. In this study, skin swabs of seabass farmed in the Aegean Sea were analysed with regard to the isolation and identification of Pseudomonas. Bacterial microbiota of skin samples (n = 96) from 12 fish farms were investigated using next-generation sequencing (NGS) and metabarcoding analysis. The results demonstrated that Proteobacteria was the dominant bacterial phylum in all samples. At the species level, Pseudomonas lundensis was identified in all samples. Pseudomonas, Shewanella, and Flavobacterium were identified using conventional methods and a total of 46 viable (48% of all NGS+) Pseudomonas were isolated in seabass swab samples. Additionally, antibiotic susceptibility was determined according to standards of the European Committee on Antimicrobial Susceptibility Testing (EUCAST) and Clinical and Laboratory Standards Institute (CLSI) in psychrotrophic Pseudomonas. Pseudomonas strains were tested for susceptibility to 11 antibiotics (piperacillin-tazobactam, gentamicin, tobramycin, amikacin, doripenem, meropenem, imipenem, levofloxacin, ciprofloxacin, norfloxacin, and tetracycline) from five different groups of antibiotics (penicillins, aminoglycosides, carbapenems, fluoroquinolones, and tetracyclines). The antibiotics chosen were not specifically linked to usage by the aquaculture industry. According to the EUCAST and CLSI, three and two Pseudomonas strains were found to be resistant to doripenem and imipenem (E-test), respectively. All strains were susceptible to piperacillin-tazobactam, amikacin, levofloxacin, and tetracycline. Our data provide insight into different bacteria that are prevalent in the skin microbiota of seabass sampled from the Aegean Sea in Turkey, and into the antibiotic resistance of psychrotrophic Pseudomonas spp. [ABSTRACT FROM AUTHOR]

Wild fish attracted to salmon farms feed on waste feed that presently contain high levels of fatty acids of terrestrial origin. This study examines whether mature Atlantic cod (Gadus morhua) caught at spawning grounds has eaten salmon waste feed. Cod were caught at four spawning grounds around Smøla (Norway), an area with multiple salmon farms, during the spawning season in 2018 (n = 327) and 2019 (n = 488). The fatty acid (FA) profile of their livers, gonads (ovary and testis), and muscles (2019) were determined. Multivariate k-mean cluster analysis of liver FA profiles revealed three main clusters, which could be allocated to trophic niches using known fatty acid trophic markers (FATMs). Of the sampled cod in 2018 and 2019, 13 % and 20 % respectively had high liver concentrations of terrestrial FATMs (18:1n-9, 18:2n-6, and 18:3n-3), indicating waste feed feeding. The remaining cod could be assigned to either the pelagic or benthic food chain. The cod identified as feeding on waste feed had large, fatty livers. The terrestrial FAs were also transferred to the muscle and gonad lipids. It is postulated that the latter may result in gametes with sub-optimal lipid composition, potentially impacting fitness, which warrants further investigation. [ABSTRACT FROM AUTHOR]

The role of weed fish species as vectors of diseases of the marketable fish farmed is studied in fisheries in various regions of the republic in the period of 2013-2021. Parasitic infections of weed fish in cyprinid fish farming ponds are revealed. More than 20 species of parasites have been recorded in these two studied fish species. Most of the parasites have a broad specificity and have been found in other fish species. The emergence and re-emergence of fish diseases is often associated with the invasion of disseminators of parasitic diseases in aquaculture. Usually, weed fish play role as propagators of these diseases. Pathogenic infusorians species (Ichthyophthirius multifiliis, Chilodonella piscicola), helminthes (Gyrodactylus elegans, Botriocephalus acheilognathi), and parasitic crustacean (Lernaea cyprinacea) are considered a major cause of high level of morbidity and mortality of the farmed fish in Azerbaijan. [ABSTRACT FROM AUTHOR]

The paper proposes an analysis of the fishing sector in Romania, from the perspective of the exploitation of natural resources. Romania's hydrographic network represents over 3.5% of the country's total area. Fishing and aquaculture are activities carried out in all regions of the country. In the areas along the rivers and the Black Sea, fishing is the primary source of income for the population of the region. In the last decades, fish production from aquaculture has regularly exceeded the catch. Romania's foreign trade with fish and aquatic products has an unbalanced balance, with a significant dependence of the domestic market on imports. The average annual fish consumption per capita in Romania is below the European average, although a positive evolution has been recorded in the recent period. The implementation of European projects by the companies operating in the Romanian fishing sector is difficult, the degree of access to the funds available to the domestic sector being characterized by a relatively low level of absorption. The lack of effective measures from the public authorities to support the national fishing sector will accentuate its decline, and the domestic market's dependence on imports from abroad will continue to grow. The research results can be useful to companies in the fishing sector, for accessing European funds, and to public authorities, in developing appropriate public policies and strategies. [ABSTRACT FROM AUTHOR]

Aquaculture provides more than 50% of all seafood for human consumption. This important industrial sector is already under pressure from climate-change-induced shifts in water column temperature, nutrient loads, precipitation patterns, microbial community composition, and ocean acidification, all affecting fish welfare. Disease-related risks are also shifting with important implications for risk from vibriosis, a disease that can lead to massive economic losses. Adaptation to these pressures pose numerous challenges for aquaculture producers, policy makers, and researchers. The dataset AqADAPT aims to help the development of management and adaptation tools by providing (i) measurements of physicochemical (temperature, salinity, total dissolved solids, pH, dissolved oxygen, conductivity, transparency, total nitrogen, ammonia, nitrate, nitrite, total phosphorus, total particulate matter, particulate organic matter, and particulate inorganic matter) and microbiological (heterotrophic (total) bacteria, fecal indicators, and Vibrio abundance) parameters of seawater and (ii) biochemical determination of culturable bacteria in two locations near floating cage fish farms in the Adriatic Sea. Water sampling was conducted seasonally in two fish farms (Cres and Vrgada) and corresponding reference (control) sites between 2019 and 2021 of four vertical layers for a total of 108 observations: the surface, 6 m, 12 m, and the bottom. Data Set:  https://doi.pangaea.de/10.1594/PANGAEA.950280. Data Set License: Creative Commons Attribution 4.0 International (CC-BY-4.0). [ABSTRACT FROM AUTHOR]

The objective of this work was to evaluate the predation rates of two genera of Odonata Miathyria Kirby, 1889 and Erythemis Hagen, 1861 in post-larviculture of tilapia with and without availability of Chironomidae. For that, 3 experiments were carried out, the first to analyze which size scale of these two genera would be more efficient in the predation of tilapia and the other 2 experiments with the selected size scales, to analyze the predation rates on tilapia with different Odonata densities, with and without availability of the aquatic insect Chironomidae. For statistical analysis of the data, an analysis of variance (ANOVA) was applied with the Duncan test searching for the means in all experiments. In experiments 2 and 3 a linear regression model was also applied. In experiment 1, there were significant differences between treatments, and in the phase with Miathyria the predation of tilapia post-larvae was higher among odonates that corresponded to the size scale from 7.1 to 9.9 mm and therefore the scale was also selected for the next experiments. For Erythemis, the consumption of tilapia was higher in the size scale between 12.1 to 14,2 mm. In the following experiments, there were significant differences between treatments. With the increase in Odonata densities the predation of the fish was greater. With the availability of Chironomidae, the consumption of tilapia post-larvae decreased. The consumption of Chironomidae was higher than the consumption of fish in experiment 3. Miathyria proved to be more efficient than Erythemis in predation and the use of Chironomidae can be a sustainable alternative for post-larvae predation control on fish farms.

The objective of this work was to evaluate the predation rates of two genera of Odonata Miathyria Kirby, 1889 and Erythemis Hagen, 1861 in post-larviculture of tilapia with and without availability of Chironomidae. For that, 3 experiments were carried out, the first to analyze which size scale of these two genera would be more efficient in the predation of tilapia and the other 2 experiments with the selected size scales, to analyze the predation rates on tilapia with different Odonata densities, with and without availability of the aquatic insect Chironomidae. For statistical analysis of the data, an analysis of variance (ANOVA) was applied with the Duncan test searching for the means in all experiments. In experiments 2 and 3 a linear regression model was also applied. In experiment 1, there were significant differences between treatments, and in the phase with Miathyria the predation of tilapia post-larvae was higher among odonates that corresponded to the size scale from 7.1 to 9.9 mm and therefore the scale was also selected for the next experiments. For Erythemis, the consumption of tilapia was higher in the size scale between 12.1 to 14,2 mm. In the following experiments, there were significant differences between treatments. With the increase in Odonata densities the predation of the fish was greater. With the availability of Chironomidae, the consumption of tilapia post-larvae decreased. The consumption of Chironomidae was higher than the consumption of fish in experiment 3. Miathyria proved to be more efficient than Erythemis in predation and the use of Chironomidae can be a sustainable alternative for post-larvae predation control on fish farms. [ABSTRACT FROM AUTHOR]

Since the 1980s, fish farming (aquaculture) has been an important contributor to Scotland's economy, but there are concerns that nutrient-rich food waste and excreta from these farms are causing eutrophication. Water quality monitoring preceding the arrival and subsequent expansion of the industry is limited. Therefore, to better understand the impacts of in-lake fish farms on the quality of freshwater ecosystems, we examined the diatom records in sediment cores from seven freshwater lochs in Scotland over a timescale of c.100–200 years, spanning the period before and after installation of the fish cages at these sites. At three lochs (A, C, E) we observed marked diatom assemblage shifts indicative of eutrophication, coincident with arrival of the fish farms, at two lochs (B, G) there was evidence of enrichment over a longer timescale although with some further enrichment occurring with the advent of the fish farms, and at the other two lochs (D, F), diatom shifts were subtle and showed no sign of eutrophication. Thus, while marked ecological shifts are shown to occur with the arrival of fish farms in some sites, this is not always the case. The natural background conditions, the scale of operations, the siting of the fish cages in relation to location of inflows and outflows, the role of flushing rate and additional sources of nutrients are discussed as potential factors for the variable impacts observed across the seven lochs. Such factors should be considered when planning future installation and expansion of fish farms to ensure sustainable development of these resources. Our study provides an understanding of baseline conditions and long-term water quality trajectories in freshwater lakes with fish farms and demonstrates the value of paleolimnology in supporting management decisions with respect to fisheries. [Display omitted] • Diatom changes coincide with the arrival of fish farms at five lochs. • At two lochs, freshwater fish farms have not led to eutrophication. • The degree of impact is dependent on local conditions. • Paleolimnology is valuable for assessing ecological change caused by fish farms. • A long-term perspective can help to support management decisions. [ABSTRACT FROM AUTHOR]

In this work, we extracted chitosan from marine amphipods associated with aquaculture facilities and tested its use in crop protection. The obtained chitosan was 2.5 ± 0.3% of initial ground amphipod dry weight. The chemical nature of chitosan from amphipod extracts was confirmed via Raman scattering spectroscopy and Fourier transform infrared spectroscopy (FTIR). This chitosan showed an 85.7–84.3% deacetylation degree. Chitosan from biofouling amphipods at 1 mg·mL−1 virtually arrested conidia germination (ca. sixfold reduction from controls) of the banana wilt pathogenic fungus Fusarium oxysporum f. sp cubense Tropical Race 4 (FocTR4). This concentration reduced (ca. twofold) the conidia germination of the biocontrol fungus Pochonia chlamydosporia (Pc123). Chitosan from amphipods at low concentrations (0.01 mg·mL−1) still reduced FocTR4 germination but did not affect Pc123. This is the first time that chitosan is obtained from biofouling amphipods. This new chitosan valorizes aquaculture residues and has potential for biomanaging the diseases of food security crops such as bananas.

While aquaculture is quickly expanding throughout the Volta Basin and creating several economic benefits, environmental reservations about the cage fish farming industry's externalities have risen. The pollution, potential sources, ecological risk, and concentrations of heavy metals (Cd, Pb, Ni, Cr, Mn, Fe, Zn, Cr, and As) in sediments were investigated in four cage aquaculture farms (fish farms A, B, C, and D) and control using an atomic absorption spectrometer. The metal concentrations of Zn (0.01 ± 0.001 mg/kg (dw)) and Mn (25.22 ± 1.509 mg/kg (dw)) were the lowest and highest in control and fish farm A, respectively. Heavy metal loads in the farms were in the order: fish farm C (50.14 mg/kg dw) > fish farm D (47.20 mg/kg dw) > fish farm A (40.98 mg/kg dw) > fish farm B (38.61 mg/kg dw) > control (8.44 mg/kg dw). Except for Pb in fish farms C and D, all other heavy metals found in the sediment were below the US EPA and WHO maximum residue levels. Pollution assessment using various indices suggested negligible anthropogenic disturbances except for Mn (moderate enrichment in farms A, B and the control) and Pb (severe enrichment in farms C and D). Ecological risk analysis suggested no potential risk to the benthos in the sediment. PCA revealed that metals were primarily from lithogenic and anthropogenic sources. Other physical, biological, and chemical aspects will need to be investigated in the future to obtain a greater understanding of the environmental impact of cage fish farming in the Basin. [ABSTRACT FROM AUTHOR]

Antimicrobial resistance is a global health challenge caused by the ability of microorganisms including bacteria, fungi, protozoans and viruses to survive the effects of drugs that hitherto were effective against them. This study sought to investigate the presence of antibiotic-resistant bacteria and their corresponding molecular determinants in fish farms of the Central and Western Regions of Ghana. Management practices and antibiotic use at the fish farms were obtained through the administration of a questionnaire. Coliform and Gram-positive bacterial loads of catfish (Clarias gariepinus), tilapia (Oreochromis niloticus) intestinal microbiota, and pond water samples recovered on MacConkey Agar and Mannitol Salt Agar were determined. Bacterial isolates were identified using various biochemical assays. Antibiotic resistance profiles and possible responsible genes of bacterial isolates were determined using the disc diffusion and Polymerase Chain Reaction (PCR) methods respectively. The study revealed that none of the fish farm managers admitted using antibiotics for prevention and treatment of diseases and no major disease outbreak had ever been recorded. Bacterial loads of pond water exceeded the acceptable level of ≤100 E. coli and

As a result of the freshwater sacristy and growing demands for fish production, the usage of fresh Nile water (Ri-W) for fish cultivation has been banned and replaced by the usage of agricultural drainage water (ADW). The agricultural drains collect wastewater from various sources that pose a potential for metal pollution. Subsequently, affect the quality of water and sediments of the receiving fish farm and poses health hazards to cultured fish and man. Farms' sediments act as a reservoir for metals and an internal source of metal. Thus, the evaluation of its metal contents and their indications are preferred for tilapia culture management. The present study investigates the levels of 7 metals (essential, and non-essential) in the surficial sediments of three fish farms irrigated with two different water sources (RiW, and ADW). Followed by an evaluation of sediment pollution and potential ecological risks using pollution indices (PI) and sediment quality guidelines (SQGs). The results indicated that the mean levels of the metals at the three fish farms follow the decreasing order of Fe (> 50,000 ppm) > Mn (700 ppm) > Zn (110 ppm) > Cr (75 ppm) > Cu (55 ppm) > Cd = Pb (not detected). According to PI, all metals were depleted to mineral levels (enrichment factor (EF) < 2 and showed unpo uted status and a most at ase ine eve s 1) relative to geoaccumulation index (I geo), contamination factor (CF), and pollution loading index (PLI). According to ecological risks, the adverse effects due to Zn and Mn were unlikely to be noticed, in contrast, a slight risk may occur due to Cu, and Cr. There were no restrictions on using ADW for fish cultivation, where sediments were not considered a source of secondary metal pollution. Continuous monitoring and evaluation of the pollution status of farm sediments are recommended. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine molecular typing and comparison analysis of 24 Aeromonas hydrophila isolated from the diseased fish with hemorrhagic septicemia in freshwater ponds and cage in Mosul and Duhok cities, Iraq. A total of 24 A. hydrophila isolates that were collected from various fish ponds and cage, were used in this study. Identification of isolates was made by the standard microbiological and molecular methods. ERIC-PCR was done with different primers to establish the genetic relationship between strains. ERIC-PCR typing showed that 24 strains of A. hydrophila were classified into 11 ERIC types (genotypes). Genotypes 9 and 7 represented the most prevalent clone. All A. hydrophila strains that were isolated from the same fish were genetically diverse. There was minimal genetic similarity between some strains which were retrieved from the same geographical source area. Also, some isolates from different geographic source area were showed a 100% genetically similar. Aeromonas hydrophila was genotypically heterogeneous and clonally dispersed among different fish ponds and cage in Mosul and Duhok cities, Iraq. Besides, one fish can be infected with more than one strains of A. hydrophila.

Farming seabass (Dicentrarchus labrax) is an essential activity in the Mediterranean basin including the Aegean Sea. The main seabass producer is Turkey accounting for 155,151 tons of production in 2021. In this study, skin swabs of seabass farmed in the Aegean Sea were analysed with regard to the isolation and identification of Pseudomonas. Bacterial microbiota of skin samples (n = 96) from 12 fish farms were investigated using next-generation sequencing (NGS) and metabarcoding analysis. The results demonstrated that Proteobacteria was the dominant bacterial phylum in all samples. At the species level, Pseudomonas lundensis was identified in all samples. Pseudomonas, Shewanella, and Flavobacterium were identified using conventional methods and a total of 46 viable (48% of all NGS+) Pseudomonas were isolated in seabass swab samples. Additionally, antibiotic susceptibility was determined according to standards of the European Committee on Antimicrobial Susceptibility Testing (EUCAST) and Clinical and Laboratory Standards Institute (CLSI) in psychrotrophic Pseudomonas. Pseudomonas strains were tested for susceptibility to 11 antibiotics (piperacillin-tazobactam, gentamicin, tobramycin, amikacin, doripenem, meropenem, imipenem, levofloxacin, ciprofloxacin, norfloxacin, and tetracycline) from five different groups of antibiotics (penicillins, aminoglycosides, carbapenems, fluoroquinolones, and tetracyclines). The antibiotics chosen were not specifically linked to usage by the aquaculture industry. According to the EUCAST and CLSI, three and two Pseudomonas strains were found to be resistant to doripenem and imipenem (E-test), respectively. All strains were susceptible to piperacillin-tazobactam, amikacin, levofloxacin, and tetracycline. Our data provide insight into different bacteria that are prevalent in the skin microbiota of seabass sampled from the Aegean Sea in Turkey, and into the antibiotic resistance of psychrotrophic Pseudomonas spp.

Monogenean trematodes, particularly those belonging to the Diplectanidae family, are significant metazoan parasites with substantial implications for aquaculture expansion. This study, investigatied the occurrence, prevalence, and pathological impact of Diplectanum spp. in European seabass (Dicentrarchus labrax) across three distinct Egyptian fish farms. During 2021–2022, we sampled 1800 European seabass (Dicentrarchus labrax) from three Egyptian fish farms (600 fish per farm). Farms 1 and 2 used semi-intensive earthen pond systems, while Farm 3 utilized an intensive floating cage system. Employing Clinical, post-mortem, parasitological, and molecular examination technique. Pathological lesions were identified, including skin and gill discoloration, emaciation, and internal organ abnormalities. Seasonal prevalence exhibited significant variations between farms, with highest rates observed in spring and Farm 3 reached an overall peak prevalence of 84.67 %. Parasitological examination distinguished two Diplectanum species morphologically, while molecular techniques exhibited limited specificity. Histopathology unveiled damage to gill, liver, spleen, kidney, and intestine, attributed to Diplectanum haptors including inflammation and internal bleeding, potentially leading to secondary infections. Molecular identification via PCR targeting ITS and 28SrDNA genes, revealing similar band sizes for the two Diplectanum species, indicating limited intraspecific genetic diversity. The study emphasizes investigating parasitic infections' prevalence and impact in aquaculture, necessitating robust molecular techniques for species differentiation. This study underscores the importance of investigating the prevalence and impact of parasitic infections in aquaculture. It highlights the need for robust molecular techniques to differentiate species. By focusing on Diplectanum spp. infections in D. labrax, the study offers valuable insights into managing parasites in aquaculture effectively. • Peak prevalence of Diplectanum spp. was 84.67 % in Farm 3's floating cage system. • Lesions included skin/gill discoloration, emaciation, and organ abnormalities. • Spring had highest prevalence, with significant variations across different farms. • Molecular techniques showed limited specificity for Diplectanum species. • Histopathology revealed damage to gill, liver, spleen, kidney, and intestine. [ABSTRACT FROM AUTHOR]

Aquaculture provides more than 50% of all seafood for human consumption. This important industrial sector is already under pressure from climate-change-induced shifts in water column temperature, nutrient loads, precipitation patterns, microbial community composition, and ocean acidification, all affecting fish welfare. Disease-related risks are also shifting with important implications for risk from vibriosis, a disease that can lead to massive economic losses. Adaptation to these pressures pose numerous challenges for aquaculture producers, policy makers, and researchers. The dataset AqADAPT aims to help the development of management and adaptation tools by providing (i) measurements of physicochemical (temperature, salinity, total dissolved solids, pH, dissolved oxygen, conductivity, transparency, total nitrogen, ammonia, nitrate, nitrite, total phosphorus, total particulate matter, particulate organic matter, and particulate inorganic matter) and microbiological (heterotrophic (total) bacteria, fecal indicators, and Vibrio abundance) parameters of seawater and (ii) biochemical determination of culturable bacteria in two locations near floating cage fish farms in the Adriatic Sea. Water sampling was conducted seasonally in two fish farms (Cres and Vrgada) and corresponding reference (control) sites between 2019 and 2021 of four vertical layers for a total of 108 observations: the surface, 6 m, 12 m, and the bottom.

Fish farming is the fastest growing sector in fish production, so it is seen as a major source of fish production in large quantities. Therefore, Iraq has moved towards developing fish farming, as it has a major role in investment expansion and a pillar of economic development. Environmental diversity has led to the availability of the vast water bodies in Iraq, which allow the breeding of different types of fish, lead to the success of fish farming projects in Iraq. The results of the research showed that the cost of fingerlings, pesticides and rented labor is the highest, as it constitutes 20% of the total variable costs, followed by the cost of fodder, then the costs of medicines, and finally the costs of transportation. As for the total fixed costs, the cost of renting land constitutes the highest percentage, followed by the construction of ponds and family work. The results of the research also showed that there is a big difference between the area and the optimum size of fish production, which is equal to 74 dunums of area and 693 tons of production with the actual level of area and production, which equals 46 dunams of area and 166 tons of production. So farmers must be helped to increase production that achieves economic efficiency by increasing areas through participation and union between farmers. [ABSTRACT FROM AUTHOR]

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Studies of acanthocephalans have increased due to outbreaks in Brazilian fish farms. This review aimed to compile results of studies carried out in Brazil, which have reported occurrences of acanthocephalans in fish from fish farms, discuss histopathological and haematological implications, and describe the different treatments in use to combat these parasites. Scientific articles, short communications, monographs, dissertations and theses are included. Eight species of acanthocephalans have been recorded: Neoechinorhynchus buttnerae, Neoechinorhynchus sp. and Echinorhynchus jucundus, Echinorhynchus gomesi, Polyacanthorhynchus macrorhynchus, Polyacanthorhynchus sp., Pomphorhynchus sp., and Quadrigyrus sp. Studies of histopathology and haematology have reported perforations, inflammation and changes in host intestines and immune cells, due to infection with acanthocephalans. Early-stage testing, both in vitro and in vivo, has shown essential oils, oleoresins and plant extracts to be highly efficacious in combating acanthocephalans. However, there are no national records regulating the use of these anthelmintics in commercial fish farms. In view of this, we are recommending good management practices, including (a) cleaning tanks after fish removal (drying the soil and adding hydrated lime); (b) crop cycles with time intervals, (c) acquisition of healthy fry followed by quarantine; and (d) controlled feeding. [ABSTRACT FROM AUTHOR]

The necessity of balancing conservation issues with the protection of aquaculture activities drives research to quantify the impact of the Great Cormorant Phalacrocorax carbo and to identify the best mitigation strategies. This study aims to characterise the diet in relation to the possible impact of the Great Cormorant on the extensive aquaculture farms in Friuli Venezia Giulia region in the upper Adriatic Sea. The diet of the species was investigated by analysing 459 pellets, collected monthly during the winter 2006/2007 in the three most important roosts of the Friuli Venezia Giulia coastline. Cormorants proved to feed mainly on typical fish species of lagoon and coastal waters. By frequency, Sand Smelts Atherina boyeri (54%) and Flounders Platichthys flesus (26%) were the main prey. Flounders played an important role also in terms of biomass (35%), together with mullets (Mugilidae, 28%). Commercially-important aquaculture species (European Seabass Dicentrarchus labrax and Gilthead Bream Sparus aurata) represented only 2% and 14% by frequency and biomass. The diet analysis supports our previous studies, carried out by behavioural observations on Cormorants foraging at different depths, on interactions with the main prey and strategies of exploitation of the fish farms. Our data imply that the Great Cormorant does not have a large effect on aquaculture yield in the north Adriatic Sea. [ABSTRACT FROM AUTHOR]

Background. The climate changes observed in the world over the past several decades strongly affect global aquaculture and fisheries. Ukraine is among the 24 countries, whose aquaculture and inland fisheries are currently facing medium stress, and will be potentially under higher stress in the future. The purpose of our work was to find a relation between air temperature and its impact on the spreading of infectious in freshwater aquaculture of Ukraine in the context of global climate change. Materials and methods. During 2011–2017, an epizootiological survey on experimental fishery farms of different patterns of ownership was conducted. The objects of research were the clinically healthy and diseased freshwater fish of different age groups, as well as parasites and bacteria of different etiological groups that affect aquatic organisms. A review of the clinical and parasitological study of different age groups and hybrids of silver carp, Hypophthalmichthys molitrix (Valenciennes, 1844) and bighead carp, Hypophthalmichthys nobilis (Richardson, 1845), common carp, Cyprinus carpio Linnaeus, 1758, and some cultured rainbow trout, Oncorhynchus mykiss (Walbaum, 1792), and brown trout, Salmo trutta were conducted. Research methods common for ichthyopathology, microbiology, and fisheries were used. Results. The study on fish diseases was conducted both in aquaculture and natural waters, in particular in the reservoirs of the Dnieper Cascade. Not only the growth and development of fish but also the signs and the course of various diseases appeared to depend on water temperature. The resistance of the fish and other hydrobionts to the influence of threshold temperatures depends on their adaptation to particular factors. In the years with a relatively warm vegetation period, the infection rates significantly increased to 25% and above. A significant broadening of the spectrum of parasitic infections over the last decade has been noted. An ecological misbalance in the ecosystems, an increase in the level of organic pollution of water, and, as a result, in the number of pathogenic microorganisms that may be harmful to fish and human health were registered. Conclusion. Taking into account the results of the analytical studies regarding climate change in Ukraine, we can predict outbreaks of bacterial and parasitic diseases in fish in the years to come, which may cause significant economic damage to aquaculture farms.

Prochilodus magdalenae is an endemic fish species of Colombia known as an important resource of commercial interest for many communities related to fishing activities as a livelihood activity. However, population deterioration has been observed in natural environments due to factors such as overfishing, fragmentation of ecosystems, among others. This makes it necessary to characterize the genetic diversity of P. magdalenae in the productive systems of some fish farms, which are used to restocking in other basins of Colombia and, thus, to propose technical and scientific criteria that allow the development of management strategies for the conservation of this species. Therefore, in 2013, caudal fin tissue was collected from 1044 individuals in seven fish farms, which were processed in the laboratory. Through the use of seven microsatellites, genetic metrics such as: observed and expected heterozygosity, number of alleles, fixation indexes, F statistics, Bayesian grouping and AMOVA were evaluated. We observed low heterozygosity, correlated with inbreeding processes, which contrast with the high values obtained in the expected heterozygosity index and the number of alleles detected in P. magdalenae productive systems. A moderate genetic differentiation between fish centers was detected and the existence of three genetic groups was observed through the Bayesian analysis. Despite the low diversity reported regarding the others species of the same genus, populations held in Bocachico captivity have the potential to restore the diversity of wild populations. Therefore, it is suggested that each fish station should establish batches of breeders separately, based on their genetic information so that there is congruence between the released individuals and those that inhabit the natural environment.

The objective of study was to isolate and determine the identity of denitrifying bacteria from limnetic areas of Lake Tota (Colombian Andes) with and without rainbow trout production activities. We examined the relationships between the lake’s physicochemical factors (oxygen, nitrogen, and phosphorus content) and two bacterial communities (denitrifying bacteria and coliforms). Water samples were taken 20 m below the surface from July to September at five limnetic zones; two of which were close to rainbow trout farming areas. In each zone, the concentrations of oxygen, nitrogen, and phosphorus were measured. To identify and quantify the abundance of bacteria, the most probable number (MPN) technique was used, employing minimal medium for denitrifying bacteria and medium for nitrate reducing bacteria (NRB). A greater number of denitrifying bacteria were found in the fish farming zones, identifying bacteria of the genera Bacillus, Pseudomonas, Nocardia, and Streptomyces. The number of nitrate-reducing bacteria revealed statistically significant differences throughout the sampling period, increasing from July to September and was related to a decrease in precipitation. The density of NRB and total phosphorus were directly correlated. High bacterial densities of denitrifying bacteria and coliforms are indicative of changes from oligotrophic to eutrophic states in the studied limnetic areas.

The article presents the analysis and prospects of commercial aquaculture in the southern regions of Russia. Rostov and Astrakhan region and Krasnodar Krai are the leaders in commercial fish production. Rostov region annually grows 23-24 thousand tons. In Krasnodar region in the period from 2018 to 2022 there was a 15% growth of avcaculture production and in 2022 it was 23,3 thousand tons. In the Astrakhan region from 2018 to 2021 there was a decrease in this indicator by 13%, but in 2022 the volume of production in the region increased to 20.5 thousand tons. Absolute parameters in Stavropol Krai (11.8-12.3 thousand tons) Kabardino-Balkarian Republic (2.5-3.3 thousand tons) and Volgograd Oblast (2.3-2.5 thousand tons) remained almost unchanged. Significant growth of relative production parameters was noted in the Republic of Dagestan, the Republic of North Ossetia-Alania and the Republic of Crimea. The main objects of cultivation in the South of Russia are carp fish. A substantiation of creating a state-owned structure ensuring practical interaction between economic entities, executive bodies of state power, scientific and educational institutions is offered.