Letteratura scientifica selezionata sul tema "Recirculated aquaculture systems"

Modern aquaculture technologies are made with the help of recirculation systems, which require the use of innovative and highperformance solutions for the treatment of recirculated water. Aquaculture recirculation is essentially a technology for growing and developing fish or other aquatic organisms by reusing water for more intensive fish production. The technology is based on the use of mechanical and biological filters, and this ecological method can be implemented for any species cultivated in aquaculture, such as fish, shrimp, mussels, etc. The scientific paper presents a brief summary of the control and solution of the main problems faced by water recirculation systems.

A sustainable aquaculture solution can be provided by Recirculated Aquaculture Systems or RAS, nevertheless, Abiotic stress factors can negatively impact aquatic organisms' growth and well-being. This study’s purpose is to demonstrate how Random Forests machine learning method helps to develop a predicting model that can aid in forecasting and in the mitigation of abiotic stressors in Recirculating Aquaculture Systems by regulating water quality influences. The study used the historical data on water quality, such as temperature, dissolved oxygen, pH, ammonia, and TDS levels in constructing a Random Forest-based predictive model. Based from the results reveal, the developed prediction model using random forests machine learning method was 90% accurate in making prediction and improved abiotic stress in RAS. Understanding the complex relations between water quality indicators and abiotic stress variables in RAS is crucial for identifying major abiotic stress drivers and developing effective models for forecasting water quality parameters, which results in real-time insights and actionable information for making proactive decisions and employing adaptive management techniques. Furthermore, RAS improves aquaculture productivity while reducing environmental impacts, which results in increased productivity, resource utilization, and system performance. This study makes a vital contribution to the aquaculture sector by proposing a data-driven method to improve the control of water quality parameters in RAS and, eventually, raise the sustainability and effectiveness of Recirculating Aquaculture Systems

Purpose. Determining the growth dynamics of whitefish juveniles in conditions of recirculated aquaculture systems to current needs of industrial aquaculture of Ukraine. Methodology. The work was performed in accordance with generally accepted guidelines used for coregonid rearing in industrial aquaculture. The study was conducted in a specialized farm for whitefish breeding - "Lavaretus" LLC. Findings. Weight and linear growth during the period of cultivation in controlled conditions of whitefish young-of-the-year were characterized by dynamics, which were generally close to that typical for coregonids. The study included four coregonid species with different feeding types. Planktivorous (peled), bentivorous (whitefish), polyphagous species that is able to feed on various food organisms (muksun) and peled/broad whitefish hybrid. Feeding regime: during the transition to the mixed feeding was carried out 48 times a day (14 hours with an interval of 15 and 30 minutes) manually; further, according to an increase in fish weight was reduced to 4 times a day using automatic feeders. The average weight and length of young-of-the-year grown in a recirculating aquaculture system was: - peled – 5.6 ± 0.4, muksun – 10.1 ± 0.6.9, Baltic whitefish – 8.6 ± 1.2 g, peled/broad whitefish hybrid – 7.9 ± 0.2 g. The coefficient of variability of weights were: peled – 40.4%, muksun – 32.2%, Baltic whitefish – 21.1%, peled/broad whitefish hybrid – 41.9%. Originality. New data on piscicultural-biological parameters and dynamics of growth of juveniles of various coregonids or cultivation in conditions of a recirculating aquaculture system were obtained. Practical value. The development of whitefish farming technology in RAS conditions, which, in contrast to salmon cultivation, is only at the initial stage of implementation, so obtained data will be the basis for the development of whitefish culture in Ukraine. Key words: recirculating aquaculture system, young-of-the-year, coregonids, length-weight parameters, rearing.

The presence of geosmin and 2-methylisoborneol (MIB) in recirculated aquaculture systems has a significant negative impact on the fish production due to poor flavour quality of produced fish and increased risk of rejection by fish processers. Advanced Oxidation Processes has a high potential for removal of geosmin and MIB in water and in this study UV/H2O2 and UV/O3 has been tested in pilot scale in real aquaculture process water. First order degradations constants were between 0.6 (UV/O3) and 1.2 (UV/H2O2) h−1 for geosmin and 1.3 (UV/O3)–1.5 (UV/H2O2) h−1 for MIB. This corresponded to average half-lives between 34–69 minutes for geosmin and between 28–32 minutes for MIB. These values were one order of magnitude higher than previously reported for degradation of geosmin and MIB in demineralised and tap-water. The slower degradation rates were caused by competitive and inhibitive processes from the water matrix. The influence of the water matrix also caused increased energy consumption with EEO values 16 to 38 times higher than previously reported for geosmin and MIB removal in tap water. Improved feasibility of removing geosmin and MIB in recirculated aquaculture systems by AOPs requires pre-treatment to minimize the impact of the water matrix on the degradation kinetics.

A denitrification system based on the biodegradable polymer Poly-ɛ-Caprolactone (PCL) was tested in a laboratory-scale recirculated aquaculture system with eels in comparison to a reference system without denitrification. The experiments were conducted with fluidized bed reactors in two parallel systems to examine the feasibility and performance of the process and to observe the condition of fishes by measuring weight gain during the test-period. The most evident effect of the system with denitrification was the low nitrate concen-tration compared with the untreated reference system. A further advantage was the stability of the pH in the systems with denitrification whereas pH of the untreated water decreased due to nitrification. All over the test-period the eels showed a similar weight gain in both systems.

A ‘membrane-denitrification’ reactor (MDR) was developed and tested in a semi-technical recirculation aquaculture system in comparison to a double – without MDR – as reference system. The MDR consisted of a reactor with an ultrafiltration membrane unit for removal of micro-particles (e.g. sludge flocs, bacteria and parasites). Specific carrier material provided surfaces for biofilm growth in a fluidized bed reactor with ethanol as carbon source for denitrification. The continuous motion of these carriers cleaned the membrane surface. With online and laboratory measurements of water parameters and operational data the feasibility of the concept was verified. An advantage is that no chemicals are needed to clean the membranes. Examinations of the fish and water analyses proved an MDR can positively influence cortisol, as a stress marker, and the microflora of the aquatic system.

The most documented fibrates are gemfibrozil, clofibrate and bezafibrate, while for statins, the majority of the published literature focuses on atorvastatin and simvastatin. The present work reviews previously published research concerning the effects of these hypocholesterolaemic pharmaceuticals on fish, with a particular focus on commercially important species, commonly produced by the European aquaculture industry, specifically in recirculated aquaculture systems (RAS). Overall, results suggest that both acute and chronic exposures to lipid-lowering compounds may have adverse effects on fish, disrupting their capacity to excrete exogenous substances, as well as both lipid metabolism and homeostasis, causing severe ontogenetic and endocrinological abnormalities, leading to hampered reproductive success (e.g., gametogenesis, fecundity), and skeletal or muscular malformations, having serious repercussions on fish health and welfare. Nonetheless, the available literature focusing on the effects of statins or fibrates on commonly farmed fish is still limited, and further research is required to understand the implications of this matter on aquaculture production, global food security and, ultimately, human health.

The generation of organic waste associated with aquaculture fish processing has increased significantly in recent decades. The objective of this study is to evaluate the anaerobic biodegradability of several fish processing fractions, as well as water treatment sludge, for tilapia and sturgeon species cultured in recirculated aquaculture systems. After substrate characterization, the ultimate biodegradability and the hydrolytic rate were estimated by fitting a first-order kinetic model with the biogas production profiles. In general, the first-order model was able to reproduce the biogas profiles properly with a high correlation coefficient. In the case of tilapia, the skin/fin, viscera, head and flesh presented a high level of biodegradability, above 310 mLCH4 gCOD−1, whereas the head and bones showed a low hydrolytic rate. For sturgeon, the results for all fractions were quite similar in terms of both parameters, although viscera presented the lowest values. Both the substrate characterization and the kinetic analysis of the anaerobic degradation may be used as design criteria for implementing anaerobic digestion in a recirculating aquaculture system.

Aquaponics systems and technologies are growing primary industries in many countries, with high environmental and socio-economic advantages. Aquaponics is a closed-loop system that produces aquatic animals and plants in a new way using recirculated water and nutrients. With a growing world population expected to reach 9.7 billion by 2050, food production sustainability is a primary issue in today’s world agenda, and aquaponics and aquaculture systems can be potential contributors to the challenge. Observing the climate changes and global warming’s impact on the ecosystem, decreasing aqua animal stocks, and responding to increasing demand are turning points in the sustainability era. In the past 15 years, fish production has doubled, thus denoting that aquaponics transforms into commercial scales with a revolutionized production, high efficiency, and fewer resources’ utilization, thus requiring proper operation and management standards and practices. Therefore, this study aims to shape a new framework for sustainable aquaponics modeling and utilization as the all-in-one solution platform covering technical, managerial, socio-economic, institutional, and environmental measures within the suitability requirements. The proposed model in this study offers a systematic approach to the design and implementation of sustainability-efficient aquaponics and aquaculture systems. Through an exhaustive coverage of the topic, this research effort can be counted as a practical reference for researchers, scholars, experts, practitioners, and students in the context of aquaponics and aquaculture studies.

En aquaculture, la polyculture est une pratique d'élevage ancienne et encore très répandue, dans laquelle plusieurs espèces aquatiques peuvent être produites ensemble. Elle est de plus en plus considérée comme une option prometteuse pour améliorer l'efficacité et la durabilité des systèmes de production aquatiques, notamment en pisciculture. Or, la polyculture peut avoir des conséquences aussi bien bénéfiques (ex. recyclage des nutriments de la biomasse d'élevage diminuant les impacts environnementaux) que néfastes (ex. compétition interspécifique entraînant des problèmes de bien-être animal) sur l'élevage des poissons. Il est donc essentiel d'évaluer ses conséquences sur la production et sur le bien-être des poissons pour mettre en évidence les meilleures polycultures parmi des associations d'espèces possibles (polycultures candidates). Dans la présente thèse, nous proposons un outil d'aide à la décision, basé sur une procédure de classement en quatre étapes pour évaluer et classer des polycultures de poissons. Cette procédure de classement, basée sur une approche multi-traits permet de choisir des polycultures pour le développement de l'aquaculture. Lorsque la polyculture est pensée pour améliorer l'élevage d'une espèce d'intérêt, la procédure de classement vise successivement à (i) sélectionner des traits reflétant la compatibilité des espèces (survie et traits liés à la morphologie, la physiologie et le comportement), (ii) préparer des données issues de tests expérimentaux dans des systèmes de recirculation en circuit fermé, en les polarisant en fonction de l'expression recherchée du trait à des fins aquacoles sachant qu'un taux de croissance le plus élevé et une réponse qui soit la plus faible au stress sont recherchés, (iii) pondérer les résultats de l'évaluation des conséquences de chaque polyculture suite à la polarisation des traits, en tenant compte des priorités (ex. production et bien-être des poissons) des parties prenantes (ex. pisciculteurs, consommateurs et organismes de réglementation) et (iv) synthétiser les résultats potentiellement conflictuels en les intégrant, au-travers d'une approche multivariée, dans un indice pour faciliter le classement des polycultures candidates. L'outil d'aide à la décision peut également être appliqué à l'échelle de l'ensemble des espèces (c'est-à-dire en considérant toutes les espèces associées). Il est considéré comme un moyen efficace permettant de choisir des associations d'espèces piscicoles en aquaculture. En revanche, il reste à l'ajuster et à l'adapter à tous les systèmes de pisciculture, en vue de le rendre utilisable pour l'ensemble des productions aquacoles
In aquaculture, polyculture is an ancient and still widespread farming practice in which several aquatic species can be produced together. It is increasingly considered as a promising option to improve the efficiency and sustainability of aquatic production systems, especially in fish farming. However, polyculture can have both beneficial (e.g. recycling of nutrients from the reared biomass reducing environmental impacts) and detrimental (e.g. interspecific competition leading to animal welfare problems) consequences on fish farming. It is therefore essential to assess its consequences on production and fish welfare to highlight the best polycultures among possible species combinations (candidate polycultures). In this PhD, we propose a decision support tool based on a four-step ranking procedure to assess and rank fish polycultures. This ranking procedure, based on a multi-trait approach, allows the selection of polycultures for aquaculture development. When the polyculture is designed to improve the rearing of a species of interest, the ranking procedure aims successively at (i) selecting traits reflecting species compatibility (survival and traits related to morphology, physiology and behavior), (ii) preparing data from experimental tests in recirculated aquaculture system, polarizing them according to the desired expression of the trait for aquaculture purposes, knowing that the highest growth rate and the lowest stress response are sought, (iii) weighting the results of the assessment of the polyculture, and (iv) synthesizing potentially conflicting results by integrating them, through a multivariate approach, into an index to facilitate ranking of candidate polycultures. The decision support tool can also be applied at the whole species level (i.e. considering all combined species). It is considered as an efficient way to select fish species combinations in aquaculture. However, it remains to be adjusted and adapted to all fish farming systems, in order to make it usable for all aquatic rearing systems

Marine ornamental decapods are among the most popular invertebrates traded in the global marine aquarium industry. With the exception of the Dendrobranchiata, nearly all other major groups of decapods have at least one species traded as ornamental, the majority being caridean and stenopodidean shrimp, as well as hermit and brachyuran crabs. Found and collected in the wild from tropical coral reefs and coastal lagoons, the aquaculture of marine ornamental decapods is yet to achieve a scale that alleviates the fishing pressure affecting natural populations. Most cultivation efforts have targeted cleaner and boxing shrimp within the genera Lysmata and Stenopus, respectively. While these species are some of the most highly traded, research on their captive culture has been mainly driven by their market value rather than conservation purposes. This is likely the reason why the aquaculture of other species that are also heavily collected, such as hermit and brachyuran crabs, is yet to properly be addressed. This chapter provides an overview of the most emblematic marine ornamental decapod species currently traded for marine aquaria, including their distinctive features, as well as their collection, packing, and shipping techniques. The state of the art of marine ornamental decapod aquaculture is critically revised, with an emphasis on broodstock husbandry and maturation, larviculture, and grow-out to commercial size. Commonly employed systems for stocking breeding pairs, raising larvae, or growing juveniles are detailed, underscoring recirculated systems operating with synthetic seawater due to their potential use in coastal or inland facilities. The main bottlenecks impairing the successful breeding of these organisms are critically addressed, namely the lack of maturation diets customized to secure the nutritional needs of target species, which consequently impairs the production of high-quality larvae for cultivation. The main constraints for larviculture are also highlighted, with special emphasis on the lack of suitable live prey and the ability of several decapod species to delay metamorphosis under suboptimal larval diets. Issues on grow-out, such as poor growth performances and cannibalism, are discussed from a commercial perspective, as well as mitigation actions (e.g., use of live prey and complex shelters). There is a strong need for science-based conservation policies, where accurate data reporting and traceability along the supply chain must be implemented to promote a sustainable use of these resources. Though pricey and popular, marine ornamental decapods are no longer poorly studied when compared to a few years ago. Nonetheless, some key issues still need the attention of researchers, commercial breeders and hobbyists to ensure that these remarkable organisms can continue to be admired in the wild and in aquarium displays.

Abstract Aquaponic systems are a combination of hydroponics, growing plants in water, and aquaculture, growing of fish. The two subsystems are connected so that the water circulating between the two, transfers the waste from the fish tank to the plants, where the plants take in nutrients. The water is filtered by the plants and is recirculated back into the fish tank. Small-scale aquaponic systems are of particular interest, as they are appropriate for rural and developing locations to harvest both plants and fish for a local community. To improve the level of sustainability, the flow within the fish tank needs to be better understood since most of the power required to operate an aquaponic system is used by the fish-tank pump. The shape of the fish tank is of importance for the flow in the tank and the initial cost of the tank. In this work, the flow in a 2 m × 2 m square fish tank with curved corners was studied experimentally with a Vectrino Acoustic Doppler Velocimeter. Two inlet configurations were studied and compared to each other — inlets at each corner of the tank, and inlets at two of the corners of the tank. The results suggest that good recirculation can be achieved with the two inlet locations. The present work can be used for evaluating numerical simulations of the flow in the tank. The ultimate goal of the study is to develop an inlet-design configuration which minimizes initial and operational costs of the small-scale aquaponic system.

The article presents the practical experience and results of rainbow trout growing in a recirculated water system (RWS) of aquaculture research center of Petrozavodsk state university (PetrSU). The paper describes the characteristics of RWS, analysis of breeding conditions and feeding peculiarities of trout juveniles, analysis of final results of the growing process.