Warm Water Aquaculture Research Articles

Comparison of fish biological indicators of Clarias gariepinus hybrids grown in ras and pond farming conditions

To improve technologies in the field of commercial cultivation of aquaculture objects and further development of the warm-water aquaculture sector in Russia, we previously undertook breeding methods and approaches to obtain high-quality planting material for a promising commercial object — the African catfish Clarias gariepinus. This article presents, in a comparative aspect, the experience of growing hybrid offspring of African catfish, obtained from crossing two breeds — Mikhailovskaya and Tamanskaya, in a closed water supply system and in a pond farm in the Astrakhan region in the summer. It was shown that hybrid individuals of clariid catfish bred in a pond farm during the feeding period under consideration (from July to September) were characterized by a high specific growth rate and low feed ratio compared to hybrids grown in a recirculation system, respectively, 11.4% versus 9.87% and 0.96 versus 1. Also, based on the results of fishing, over two months of cultivation in a pond farm, hybrids of clariid catfish increased the total biomass by 13 times, while in a recirculating system it increased by 15 times, but the final biomass of fish turned out to be greater when reared in open reservoir (46.875 versus 10.87 kg). It was shown that the final individual mass of hybrid fish cultured in pond conditions was 11.0% higher than the final mass of individuals in the recirculation system. The conducted studies showed that in the climatic conditions of the Astrakhan region (VI fish-breeding zone), a promising direction for aquaculture of African catfish is the feeding cultivation of hybrid juveniles in pond farms. It should be taken into account that in order to obtain marketable fish products (i.e. individuals weighing over 1000 g), it is necessary to use fish seeding material with an average weight of at least 100 g.

Aeromonas dhakensis: A Zoonotic Bacterium of Increasing Importance in Aquaculture.

Aeromonas dhakensis is increasingly recognised to be an important pathogen responsible for disease losses in warm-water aquaculture and, similar to several other Aeromonas species, it can infect humans. Knowledge of A. dhakensis is accumulating, but this species remains relatively under-investigated compared to its close relative, Aeromonas hydrophila. The significance of A. dhakensis may have been overlooked in disease events of aquatic animals due to issues with reliable identification. Critical to appreciating the importance of this pathogen is the application of dependable molecular tools that enable accurate identification and discrimination from A. hydrophila and other motile aeromonads. This review aims to synthesise the key literature on A. dhakensis, particularly with relevance to aquaculture, including knowledge of the bacterium derived from disease case studies in aquatic hosts. Identification methods and strain phylogeny are discussed, with accurate detection important for prompt diagnosis and for distinguishing strains with heightened virulence. Increasing evidence suggests that A. dhakensis may be more virulent than A. hydrophila and correct identification is required to determine the zoonotic risks posed, which includes concerns for antibiotic-resistant strains. This review provides an impetus to improve species identification in the future and screen strain collections of presumptive Aeromonas spp. retrospectively to reveal the true prevalence and impact of A. dhakensis in aquaculture, the environment, and healthcare settings.

Artificial Intelligence Techniques based on aquaculture solar thermal water heating system control

The One of the most promising applications of hot water is aquaculture. Temperature is one of the most principle parameters affects aquaculture life. It can cause stress and mortality or superior environment for growth and reproduction. Shrimp is warm water aquaculture type need hot water supply. To increase pond production it is necessary to keep water temperature at 34oC. Artificial intelligence (AI) techniques are becoming useful as alternate approaches to conventional techniques or as components of integrated systems. They have been used to solve complicated practical problems in various areas and are becoming more and more popular nowadays. In this paper a control system using artificial neural network control (NNC) either adaptive fuzzy logic control (AFLC) are design to control the hot water temperature. A comparison study is applied between the performance of FLC and NNC. The performance of NNC is the best because the control design takes into consideration different variables which give an accurate output than FLC. Also this paper introduces a complete mathematical modeling and MATLAB SIMULINK model for the proposed aquaculture heating system.

Amyloodiniosis in aquaculture: A review

AbstractFish ectoparasites are one of the pathogens groups that pose great concern to the aquaculture industry. The dinoflagellate Amyloodinium ocellatum is responsible for amyloodiniosis, a parasitological disease with a strong economic impact in temperate and warm water aquaculture, mainly in earthen pond semi‐intensive systems. Amyloodiniosis represents one of the most important bottlenecks for aquaculture and, with the predictable expansion of the area of influence of this parasite to higher latitudes due to global warming it might also be a threat to other aquaculture species that are not yet parasitized by A. ocellatum. This review made a compilation of the existing knowledge about this parasite and the disease associated with it. It was noticed that, except from the life cycle characterisation, detection methods, histopathological analysis, and treatments, there are still a lot of areas that need a further investment in research. Areas like parasite–host interactions, epidemiological models, taxonomy, host physiological responses to parasitism, and genome sequencing, amongst others, can contribute to a better understanding of this disease. These proposed approaches and routes of investigation will enhance and contribute to a more standardised knowledge, creating the opportunity for a better understanding of amyloodiniosis impacts on fish and contributing for the development of new tools against A. ocellatum, that may reduce fish mortality in aquaculture production due to amyloodiniosis outbreaks.

Nanovaccines to Combat Aeromonas hydrophila Infections in Warm-Water Aquaculture: Opportunities and Challenges.

The application of nanotechnology in aquaculture for developing efficient vaccines has shown great potential in recent years. Nanovaccination, which involves encapsulating antigens of fish pathogens in various polymeric materials and nanoparticles, can afford protection to the antigens and a sustained release of the molecule. Oral administration of nanoparticles would be a convenient and cost-effective method for delivering vaccines in aquaculture while eliminating the need for stressful, labour-intensive injectables. The small size of nanoparticles allows them to overcome the degradative digestive enzymes and help deliver antigens to the target site of the fish more effectively. This targeted-delivery approach would help trigger cellular and humoral immune responses more efficiently, thereby enhancing the protective efficacy of vaccines. This is particularly relevant for combating diseases caused by pathogens like Aeromonas hydrophila, a major fish pathogen responsible for significant morbidity and mortality in the aquaculture sector. While the use of nanoparticle-based vaccines in aquaculture has shown promise, concerns exist about the potential toxicity associated with certain types of nanoparticles. Some nanoparticles have been found to exhibit varying degrees of toxicity, and their safety profiles need to be thoroughly assessed before widespread application. The introduction of nanovaccines has opened new vistas for improving aquaculture healthcare, but must be evaluated for potential toxicity before aquaculture applications. Details of nanovaccines and their mode of action, with a focus on protecting fish from infections and outbreaks caused by the ubiquitous opportunistic pathogen A. hydrophila, are reviewed here.

Influence of the antioxidant astaxanthin in the composition of feeds on the physiological state of heat-water objects of aquaculture

This scientific study examines the experience of using astaxanthin in tilapia feeding, and its effect on the physiological state of individuals. The work used a set of methods used in fisheries research — variation statistics and physiological and biochemical tests. The reliability and validity of the scientific provisions and conclusions contained in this work are determined by a significant amount of factual material; in total, 150 tilapia individuals were studied. The data obtained during the study indicate that the use of astaxanthin at a concentration of 20.0; 30.0; 40.0 and 50.0 mg gives the best physiological and biochemical parameters of cultivated individuals, in comparison with the control variant. However, taking into account the maximum input of astaxanthin in feed for warm-water fish species, the most effective and safe concentration of astaxanthin in the diet of warm-water aquaculture objects is 40.0 mg/kg of feed, which is also confirmed by the results of the physiological state of individuals obtained during the experiments. One of the main stages of metabolism in the body is the digestibility and assimilation of feed nutrients, the effectiveness of which to a certain extent depends on the use of biologically active substances in diets that have antioxidant properties and have a stimulating effect on the vital functions of the body. An important criterion for the choice of feed additives is environmental safety. As a result, after feeding, the indicators of total protein in the experimental variants (1, 2, 3 and 4) were higher by 27.8; 58.5; 59.5 and 52.2%, respectively, of the control group. Analyzing the data obtained after the completion of the experimental work, a significant increase in the level of hemoglobin concentration in the experimental variants was found to be 1.2–1.3 times, respectively, compared with the control variant.

Biofiltration Reactivation Kinetics of a Cyclobio Fluidized Sand Filter in a Warmwater Recirculating Aquaculture System

AbstractThe ability of a commercial‐scale Cyclobio fluidized sand filter was evaluated for ammonia and nitrite removal by dosing with ammonia chloride, NH4Cl, as part of the water treatment unit for the U.S. Department of Agriculture Agricultural Research Service Warmwater Aquaculture Research Unit's (WARU) catfish hatchery in Stoneville, Mississippi, USA. Treatment system water was recirculated through the Cyclobio filter for several months without any feed inputs; thus, our objective was to investigate how quickly a full‐scale Cyclobio fluidized sand filter could be reactivated with NH4Cl substrate dosing in preparation for the upcoming spawning season. A second objective of the study was to examine the decline of the filter's nitrification ability when the supplementary NH4Cl substrate dosings were removed or limited. The effects of daily and weekly substrate additions were evaluated over a 14‐week winter period, with the system water temperature ranging between 20° and 23°C. Total ammonia nitrogen (TAN) concentration decreased within hours of initial dosing. After approximately a 2‐h lag period, the nitrite–nitrogen concentration peaked and then decreased. The rate of TAN nitrification followed a simple first‐order reaction kinetics and increased over time during the 4 weeks of daily NH4Cl substrate dosing. The return to a weekly substrate dosage resulted in a decrease in the kinetic reaction rate, but adequate to maintain the filter during periods of system inactivity. The once‐daily substrate dosage was consumed within hours of the initial dosing and was sufficient for current system loading.

How susceptible are rainbow trout and brown trout to infection with tilapia lake virus at increased water temperature – Is there any potential for climate change driven host jump?

In poikilothermic animals like fish, outbreaks of pathogen-related diseases are closely related with the temperature of the surrounding environment. Many salmonid fish species are thermally sensitive and therefore are especially endangered by thermal stress and habitat loss caused by increasing temperatures during summer heat waves. We hypothesized that combining thermal stress and the presence of a novel viral pathogen from for example aquaculture effluents may result in a potential host jump of the pathogen. This could be one of the mechanisms leading to an increased vulnerability of salmonids to a novel disease. Tilapia lake virus (TiLV) could be considered as one of the most dangerous emerging viruses affecting warm water aquaculture of Nile tilapia. This pathogen has a global reach with a yet to be defined host range. The aim of this study was to assess the potential for TiLV to infect salmonid hosts in a range of water temperatures which can be reached during summer heatwaves in Continental Europe. For this, it was established that TiLV can replicate in vitro in salmonid cells over the wide temperature range of 15 °C to 25 °C. The susceptibility of rainbow trout and brown trout juveniles to infection with TiLV was investigated in infection trials based on cohabitation and on intraperitoneal injection of the virus in elevated water temperatures of 20 °C and 25 °C. These experiments showed that if the ability of the virus to enter the organism is considered, the susceptibility of rainbow and brown trout to the virus is low. The exposure of these salmonids to the virus by cohabitation did not lead to high virus loads in the liver and brain. However, the permissivity, i.e. the ability of the virus to replicate in the fish body, is high, because IP-injections of TiLV led to a high virus replication in internal organs. Therefore, TiLV could have some pathogenic potential in salmonids which might be exacerbated by climate change and anthropogenic activities.

Study results on the molecular genetic, morphometric and sexual characteristics of the beluga (Huso huso L., 1758) grown in the aquaculture of the Republic of Belarus

The subject of the study was the genetic and phenotypic characteristics of Beluga (Huso huso (Linnaeus, 1758)) grown in the warm-water aquaculture at the “Selets” fish farm (the Republic of Belarus). Molecular-genetic analysis was performed using STR-markers and species-specific PCR revealed the absence of hybrid individuals in the analyzed broodstock of (Huso huso L.). Affiliation of individuals to the Caspian population was established based on the sequence analysis of the 367 bp region of the mitochondrial D-loop. Using six STR loci, the population structure was analyzed. The population structure and gene pool of the only broodstock of (Huso huso L.) in Belarus were compared with domesticated (H. huso L.) from the Russian Federation. The analysis showed a lack of genetic variation and the heterozygote excess in Beluga from the Belarusian farm. Analysis of morphometric indicators revealed that the conditions in which the Beluga broodstock is kept at the fish farm “Selets” should be improved. Using ultrasound scanning, the following stages of gonad maturity were established: stages II, III, and IV in males; II, II semi-fatty, II fatty, and II-III in females. The beluga broodstock at the fish farm “Selets” is mainly represented by females (the females exceeded the males by 2.3 times in terms of their number).

Bioindicators of homeostasis’ constants of growing conditions of warm-water aquaculture objects in the context of obtaining marketable products

To create recommendations regarding the technological process of growing objects of warm-water aquaculture, the health of individuals in the created conditions of maintain is a necessary study. Taking into account the similarity of the necessary conditions for the organization of growing warm-water aquaculture objects, it is important to monitor the indicators that are bioindicators of homeostasis constants with a projection on the conditions of maintain, for subsequent adjustment of satisfactory conditions of maintain. First of all, these are hematological and biochemical bioindicators that determine the general characteristics of blood in the case of fish objects of sterlet and hemolymph in the case of crustacean objects of Australian freshwater crayfish and the concentration index of total serum protein that determines the “physiological norm”. When growing sterlet, a high level of total blood protein was established at 40.14±1.73 g/l and the hemolymph of the Australian freshwater crayfish was determined to have a protein concentration of 40.8±4.5 g/l. The presented analysis of bioindicators complements the missing information for monitoring the data of representatives of warm-water aquaculture, which will be valuable for specialists engaged in breeding these objects.

Bioindicators of the constants of homeostasis of the internal environment of crustaceans, cultured in different environmental conditions for the purpose of obtaining commodity products

The study of the composition and properties of the internal environment (hemolymph) of crustaceans grown in various conditions has an important ecological and physiological aspect, since a number of characteristics of the physiological status of objects can be used to assess the state of the environment, thus, they can be included in the number of bioindicators. However, the nature of the observed differences between objects grown under different conditions, the features of homeostatic regulatory mechanisms and the limits of the reference values of individual homeostasis constants are often not known. To formulate recommendations regarding the technological process of growing objects of warm-water aquaculture, taking into account the assessment of environmental conditions in dynamics through the analysis of indicators of the state of individuals — bioindicators — it is necessary to compare the state of individuals kept in different conditions. The object of the study was the Australian red claw crayfish Cherax quadricarinatus (Von Martens, 1868), cultivated under various conditions of intensive and semi-intensive cultivation. The studies have revealed that throughout the entire period of cultivation, individuals grown in ponds retained a high level of total protein, cholesterol and β-lipoproteins, in contrast to crayfish cultivated in pools. The values of these indicators as bioindicators indicate a high degree of compliance of the growing conditions with the needs of the studied object. Comparative assessment of fluctuations in the ratio of hemolymph shaped elements in the hemocyte composition between cancers grown under different conditions did not reveal significant differences. It was found that significantly higher growth rates are characteristic of crayfish grown in ponds, in contrast to the group of individuals cultivated in pools. The comparative analysis of bioindicators in different growing conditions presented by the authors of the article supplements information that is of significant interest for monitoring the growing conditions of this representative of warm water aquaculture, which will be valuable for specialists engaged in crustacean breeding.

Effects of stocking density on the aquaculture performance of diploid and triploid, Pacific oysterCrassostrea gigasand Portuguese oysterC. angulatain warm water aquaculture

The Pacific oyster (Crassostrea gigas) and the Portuguese oyster (C. angulata) are important oyster species for commercial aquaculture. In this study, three stocking density regimes, including 20, 30 and 40 oysters/basket, were used to study the effects of stocking density on growth performance, survival rate and lipid nutritional quality of diploid and triploid C. gigas and C. angulata. The experiment lasted 163 days, from to 22 November 2011 to 3 April 2012. The main findings of this study are as follows: (1) C. gigas has growth advantage over C. angulata in Shantou waters; (2) geographic origin of the oysters has an impact on the overall performance of diploid and triploid oysters; (3) triploids are generally no growth and survival advantage over diploids in spring and summer; (4) oysters at low stocking density were generally outperformed those at high stocking density; (5) lipid composition of oysters is not affected by ploidy and stocking density; (6) in Shantou waters, C. angulata is more nutritious than C. gigas. This study compares the performance of C. gigas and C. angulata triploidy for the first time. The findings of this study can provide useful information to be applied in oysters aquaculture.

Economic Losses of Catfish to Avian Predation: A Case Report

AbstractAvian predation in catfish aquaculture has been a persistent issue throughout the history of the industry, and as production has expanded predation from piscivorous birds has intensified. Catfish ponds in the Mississippi River delta (in the Mississippi migratory flyway) provide a constant and readily accessible supply of forage for birds. Intensive foraging by fish‐eating birds has led to a specific regulatory policy and numerous on‐farm and regional management efforts. However, in 2016, legal challenges lead to recision of some federal policies and uncertainty as to allowable management, resulting in limitations on bird depredation. Estimating the extent of fish losses to avian predators is difficult, as loss estimates from farms are often confounded with disease‐ and management‐related mortalities. This study details the reported losses to birds that were observed in commercial‐scale catfish ponds at the Thad Cochran National Warmwater Aquaculture Center, Stoneville, Mississippi, during periods of limited bird management. The observed fish losses attributed to birds ranged from 33% to 95% loss in survival and potential yield losses of 4,396 to 8,889 lb/acre, increasing production costs and decreasing net returns. Net economic losses when accounting for negative net returns and lost profits ranged from US$3,518 to $4,060/acre. Losses of this magnitude on commercial fish farms are economically detrimental, especially because catfish farms lack the compensatory economic relief programs that are available in other agriculture sectors. Roost dispersal activities that are organized by federal agencies and avoiding delays in issuing bird depredation permits are vital for mitigating this persistent and growing regulatory problem in the U.S. catfish industry.

Characterisation of myxozoan fauna of western mosquitofish, Gambusia affinis (Baird and Gerard) (Cyprinodontiformes: Poeciliidae), inhabiting experimental catfish ponds in Mississippi, USA.

Characterising myxozoan taxa parasitising fish hosts in catfish aquaculture ponds is crucial to understanding myxozoan community dynamics in these diverse and complex ecological systems. This work investigated the myxozoan fauna of the western mosquitofish, Gambusia affinis, a common, incidental species found in catfish aquaculture ponds in the southeastern United States. 598 fish were sampled in May of 2018 and 2019 from the pond facility of the Thad Cochran National Warmwater Aquaculture Center in Stoneville, Mississippi, USA. Fish were examined microscopically using wet mount preparations of fresh tissue and histology for myxozoans. 18S rRNA gene sequences were amplified from myxospores obtained at necropsy. Updated morphologic, histologic, and 18S rRNA gene sequence features are provided for Henneguya gambusi, Myxobolus pharyngeus, and Myxidium phyllium. Two potentially novel myxozoans were observed during this survey, an undocumented Myxobolus sp. associated with chondrolysis of bones throughout the body and a putative Myxobilatus sp. observed histologically in the renal tubules, ureters, and urinary bladder. However, inadequate samples were obtained for proper species descriptions. Lastly, the life cycle of M. pharyngeus, which is thought to utilize the oligochaete worm Dero digitata as their definitive host, was putatively confirmed by 18S rRNA sequence matching to actinospore stages from oligochaetes in catfish ponds in Mississippi. This work provides novel and expanded morphologic, histologic, molecular and biologic data of five myxozoan parasites of G. affinis, expanding our knowledge of myxozoan diversity in catfish aquaculture ponds.

Testing of experimental feed for young Australian red-clawed crayfish that meets its nutritional needs

One of the relatively promising types of world aquaculture is the Australian redclawed crayfish, which is one of the relatively promising objects in warm-water aquaculture. Compared to other farmed crustaceans (shrimps, crabs), Australian crayfish is characterized by a high growth rate and unpretentiousness to the conditions of aging. In the process of cultivation of red-clawed crayfish, industrial granulated feeds developed for other types of hydrobionts (shrimps, fish) are currently used. In the presence of biotechnological standards for growing juveniles and commercial products of red-clawed crayfish, the question remains open about the lack of production of balanced specialized feeds for them. The purpose of this work was to test an experimental feed developed according to its own recipe for young Australian red-clawed crayfish. The main stages of the technology of preparation of the above feed are described. The experimental feed was compared with production dry feed according to the main parameters (qualitative composition, nutritional value, consumer characteristics). Taking into account the nutritional needs of crayfish in the main nutrients (protein, fat, fiber), three types of food were selected: for loricarium catfish, for juvenile sturgeon and experimental. In accordance with them, three variants of the experiment were laid down, where the conditions of maintenance (planting density, temperature and light modes, feeding frequency) were identical, except for differences in the type of feed. During the experiment, the main differences in the size and weight parameters of groups of juvenile Australian crayfish cultured using these feeds were revealed. The necessary conditions for keeping crustaceans in the laboratory and the scheme of their control are described.

Koi herpesvirus and carp edema virus threaten common carp aquaculture in Croatia.

Common carp (Cyprinus carpio) is a very important fish species for warm-water aquaculture in Croatia. All Croatian carp farms are subjected to a surveillance programme for the presence of koi herpesvirus (KHV), causing a deadly disease called koi herpesvirus disease (KHVD). However, there is no surveillance for other viral pathogens of importance like carp edema virus (CEV), a causative agent of koi sleepy disease (KSD). During regular testing within the KHVD surveillance programme, we tested samples for CEV simultaneously. The screening indicated possible outbreaks of KHVD and KSD. During 2016, KHVD broke out in an isolated area and soon thereafter a KHV eradication programme was successfully performed. However, during 2018 and 2019, two additional mortality events occurred in lakes in the southern part of Croatia during the spring. Samples from both events tested positive for CEV. An epidemiological investigation confirmed the introduction of infected carps from an infected farm to one of the lakes. To prevent the spreading of CEV into open waters, it is of utmost importance to introduce CEV testing before fish movement or to perform regular testing of all carp farms in the country to determine CEV prevalence for the purpose of implementation of control measures.

Principles of Conservation of Biodiversity in Hydrobiocenoses Formed as a Result of Carbon and Energy Enterprises

This paper presents the principles developed by the authors for the operation of reservoirs of technogenic origin, formed as a result of the activities of coal mining and energy enterprises, which can become basic when developing models for the rational use of wastewater and land from coal mining regions: maximum environmental friendliness, reasonable technological (biotechnological) restrictions, forecasting and regulation ecological consequences of the introduction of alien objects of ichthyofauna, etc. The expediency of soft biological methods for cleaning eutrophic water bodies is substantiated. As part of the implementation of the principle of forecasting and regulating the environmental consequences of the introduction of alien fauna ichthyofauna, a new approach is proposed to create a model of variability of the hydroecosystem that will allow developing mechanisms to maintain ecological balance in water bodies and coordinate the work of hatcheries and fishing enterprises, environmental monitoring services and other institutions. The principles of a reasonable biotechnological restriction in the operation of a reservoir and the possibility of alternative use of a reservoir have found their application in the development of warm-water aquaculture using waste warm water. It is proved that the principles of operation of reservoirs of technogenic origin, formed as a result of the activities of coal mining and energy enterprises, may well be successfully implemented to preserve biological diversity in large technogenic reservoirs.

Биопродуктивность прудов VI рыбоводной зоны

Abstract. The paper highlights the prospects of cultivating heat-loving species, such as Australian crayfish and freshwater shrimps in the VI fish breeding zone. Australian crayfish and freshwater shrimps breeding is considered economically attractive for entrepreneurs, having a limited area for farming facilities. At the same time, pond ecosystems require the individual approach and close study in terms of the environmental conditions for the cultivated species upkeeping and the natural forage base that determine the pond biological productivity. Today, there are no clear recommendations on the summer keeping warmwater aquaculture species, in particular, Australian crayfish and freshwater shrimp in the Astrakhan region. To cultivate the new objects of warmwater aquaculture in 2017-2019 the small innovative enterprise Modern Sharapovskiy Fish Breeding Complex researched the production potential of ponds of various categories for receiving marketable products; there was studied the forage base, biomass of zooplankton and zoobenthos satisfying the nutritional needs of farmed objects. As a result of experimental work, it was found that in pond No.2, where freshwater shrimps were grown, there were registered 5 species of Cladocera and 1species of Rotifera, while in pond No.1 used for breeding Australian crayfish there were registered 4 species of Rotifera and only 1 species of Cladocera. Presumably, the observed species composition of the studied ponds is specified by the selectivity of the cultivated objects in zooplankton consumption. The possibility of increasing the bio-productivity of ponds by alternate growing aquaculture and agricultural products has been considered.

Control of fish parasites in aquaculture

This paper describes the results of parasitological monitoring of pond farms in the Krasnodar region. It was found that in the warm-water aquaculture of various systems, 25 species of fish parasites were invaded, and the fauna of parasites was determined. The obtained results are the basis for the analysis of the system of medical and preventive measures and actualize the development of new means and methods of treatment and prevention of diseases. It is established that the complex anthelmintic drug, according to the generally accepted classification of chemical compounds in accordance with the degree of danger, can be attributed to moderately hazardous compounds, and by cumulative properties - to the group of substances with weakly expressed cumulation. With repeated administration of the new drug to fish, there were no significant changes in the clinical status, some hematological and biochemical parameters, which is one of the necessary conditions for the possibility of using anthelmintic in clinical studies. As a result of a single therapeutic feeding with the use of a combined anthelmintic at a dose of 50 mg/kg, the 100% extensive and intensive efficiency of the deworming of carps invaded by Philometroides lusiana and Bothriocephalus acheilognathi was obtained.

Heritability and response to selection for carcass weight and growth in the Delta Select strain of channel catfish, Ictalurus punctatus

A population of channel catfish (Ictalurus punctatus), referred to as the Delta Selects, was established in 2006 and has been selected for increased growth and carcass yield as part of the USDA's Warmwater Aquaculture Unit's mission to develop improved catfish germplasm for release to U.S. catfish farmers. The base population was established from catfish collected from 10 commercial farms. Broodfish were spawned in ponds, full-sib families were reared in separate tanks until tagging at 8 to 10 months post-hatch, then fish were reared communally in earthen ponds until 16 to 18 months post-hatch. Fingerling weight, harvest weight and sex were recorded. A sample of males and females from each full-sib family was processed and carcass weight (head and viscera removed) was recorded. Pedigree was determined by assigning offspring to parents based on inheritance of microsatellite alleles. Data was collected on offspring produced in 2008, 2009, 2011, 2012, 2014 and 2015. Various statistical models were compared, and variance components and breeding values were estimated with BLUP F90 software. Selection was based on estimated breeding values for increased harvest weight and carcass yield. Fingerling weight was recorded for 27,000 fish from 945 full-sib families produced by 465 sires and 726 dams; harvest weight was recorded for 27,160 progeny from 954 full-sib families produced by 467 sires and 731 dams; and carcass weight was recorded for 6023 animals from 752 full-sib families produced by 394 sires and 588 dams. Heritabilities estimates were 0.15 for fingerling weight, 0.21 for harvest weight and 0.32 for carcass yield. Genetic correlations were 0.77 for fingerling and harvest weight and 0.20 for carcass yield and harvest weight. Genetic trends, comparison to a randomly bred control line, and correlations between mid-parent EBVs and offspring phenotypes demonstrate positive response to selection for both traits.