Search Results (41)

Small-scale fisheries and aquaculture play a crucial role in securing food, income, and nutrition for millions, especially in the Global South. Rural small-scale aquaculture (SSA) is characterized by limited investment and technical training among farmers, diversification and dispersion of farms over large areas, reduced access to competitive markets for inputs and products, and family labor. Small-scale integrated circular aquaponic (ICAq) systems, in which systems’ component outputs are transformed into component inputs, have significant potential to increase circularity and promote economic development, especially in a rural context. We offer an integrated and comprehensive approach centered on aquaponics or aquaponic farming for small-scale aquaculture units. It aims to identify and describe a series of circular processes and causal links that can be implemented based on deep study in SSA and ICAq. Circular processes to treat by-products in ICAq include components like composting, vermicomposting, aerobic and anaerobic digestion, silage, and insect production. These processes can produce ICAq inputs such as seedling substrates, plant fertilizers, bioenergy, or feed ingredients. In addition, the plant component can supply therapeutic compounds. Further research on characterization of aquaponic components outputs and its quantifications, the impact of using circular inputs generated within the ICAq, and the technical feasibility and economic viability of circular processes in the context of SSA is needed. Full article

Aquaponics, a biological production system that combines land-based aquaculture and hydroponic cultivation of plants, is a water-sharing and water-saving system that is expected to be a sustainable food production system with water and nutrient resource circulation in agricultural and fisheries fields. The balance among feeding, fish density, and plant absorption capacity was investigated to obtain fundamental data for sustainable aquaponic systems. To clarify the effects of feeding rates on biological production and nitrogen utilization efficiency, fish and plant growth performance and nitrogen flow were evaluated in an aquaponic system that combined loach aquaculture with lettuce hydroponic cultivation. Test groups with different feeding rates and different fish densities were set. As a result, the fertilizer components in loach excreta contributed to plant growth, and the growth rate of lettuce plants tended to be greater than that of control hydroponic cultivation without fish. However, there was no difference in lettuce growth at feeding rates of 0 to 2 g d⁻¹/system, but above 2 g d⁻¹/system, the growth of lettuce plants was suppressed due to an overload of excreta. The yield of loaches increased with increasing daily feeding rate per system, but a minimum feed conversion ratio was detected. The NO₂⁻ concentration increased with increasing daily feeding rate per system and amount of excreta. The nitrogen use efficiency did not change at feeding rates ranging from 0 to 1.5 g d⁻¹/system. In this feeding rate range, 80% of NUE in aquaponics was due to NUE in the plant hydroponic cultivation subsystem. However, above 2 g d⁻¹/system, nitrogen use efficiency decreased with increasing daily feeding rate per system. A feeding rate of approximately 1.5 g d⁻¹/system maximized biological production while maintaining high nitrogen utilization efficiency. In conclusion, a balance among feeding, fish density, and plant absorption capacity is essential to maintain a sustainable aquaponic system for sustainable fish and plant production as a food production system, saving water and chemical fertilizer. Full article

This study investigated the effects of dietary iron supplementation on water quality, plant growth, and fish health in an aquaponic system over 90 days. Iron supplementation significantly improved plant growth, with increased plant height, stem diameter, leaf count, and fruit yield in tomatoes (Solanum lycopersicum) and pak choi (Brassica rapa subsp. Chinensis) (p < 0.05). The water pH fluctuated with varying iron content, and higher iron levels promoted better plant growth by improving iron availability (p < 0.05). During the first 60 days, all red blood cell counts and hemoglobin levels increased, but the growth and nutritional composition of mirror carp (Cyprinus carpio var. specularis) showed no significant differences. By day 90, fish in the T3 group (800 mg/kg iron) exhibited significantly reduced growth and feed conversion rates (p < 0.05). Histological analysis of liver tissue indicated iron-induced liver damage; additionally, excessive iron intake suppressed erythropoiesis, leading to lower red blood cell counts and hemoglobin levels (p < 0.05). The results indicate that moderate iron supplementation improves plant growth, but excessive iron can negatively impact fish health, particularly liver function and blood formation. These findings provide valuable insights for optimizing iron levels in aquaponic systems. Full article

The use of Mediterranean euryhaline fish and halophytes in aquaponics presents a sustainable and alternative approach to food production. The present study investigates the effect of compensatory growth on sea bass (Dicentrarchus labrax) and Baltic prawn (Palaemon adspersus) co-cultivated with the halophytic glasswort (Salicornia europaea). Three autonomous systems were established, each containing forty-five sea bass, nine Baltic prawns, and eight glasswort plants, with different feeding regimes for each treatment: (i) daily feeding (treatment A), (ii) three days of feeding per week followed by four days of fasting (treatment B), and (iii) feeding for seven days followed by seven days of fasting (treatment C). The growth performance of the fish was significantly higher in treatment B. Conversely, the feed conversion ratio (FCR) was notably higher in treatment A. As for the prawns, their final body weight and length were similar across all treatments. The glasswort plants also demonstrated significantly improved growth in treatment B. These results indicate that the incorporation of feeding and fasting cycles can be an effective feed management strategy for polyculture aquaponic systems. Additionally, food deprivation had a positive impact on the growth performance of both glasswort and prawns. Full article

Against the backdrop of climate change, soil loss, and water scarcity, sustainable food production is a pivotal challenge for humanity. As the global population grows and urbanization intensifies, innovative agricultural methods are crucial to meet rising food demand, while mitigating environmental degradation. Hydroponic and aquaponic systems, has emerged as one of these solutions by minimizing land use, reducing water consumption, and enabling year-round crop production in urban areas. This study aimed at assessing the yield, ecophysiological performance, and nutritional content of Lactuca sativa L. and Cichorium endivia L. var. crispum grown in hydroponic and aquaponic floating raft systems, with Oreochromis niloticus L. integrated into the aquaponic system. Both species exhibited higher fresh biomass and canopy/root ratios in hydroponics compared to aquaponics. Additionally, hydroponics increased the leaf number in curly endive by 18%. Ecophysiological parameters, such as the leaf net photosynthesis rate, actual yield of PSII, and linear electron transport rate, were also higher in hydroponics for both species. However, the nutritional profiles varied between the two cultivation systems and between the two species. Given that standard fish feed often lacks sufficient potassium levels for optimal plant growth, potassium supplementation could be a viable strategy to enhance plant development in aquaponic systems. In conclusion, although aquaponic systems may demonstrate lower productivity compared to hydroponics, they offer a more sustainable and potentially healthier product with fewer harmful compounds due to the reduced use of synthetic fertilizers, pesticides, and the absence of chemical residue accumulation. However, careful system management and monitoring are crucial to minimize potential contaminants. Full article

The expansion of food production is becoming more important due to a rising world population, which is relying on food security on regional and local scales. Intensive food production systems exert a negative impact on the regional ecosystem because of agrochemical pollution and nutrient-rich water discharging into nearby rivers. Furthermore, these systems highly depend on regional water resources, causing water scarcity and soil erosion due to the overexploitation of natural resources in general. The objective of this article is to review the water usage in the two most water-intensive food production systems, agriculture and aquaculture, showing lacking areas like system management and climate change, which must be considered in the implementation of a sustainable water footprint. In addition, the review includes an analysis of the combination of both production systems in aquaponic food production and the possibilities of water saving. There are a variety of analyses related to water usage for crop and aquatic animal production, but in these analyses, there is a lack of information about system management in general, which includes cleaning processes, water substitution, pond removal, water evaporation, and, especially in aquaculture, the water usage required for industrially elaborated fish feed. Full article

AI plays a pivotal role in predicting plant growth in agricultural contexts and in creating optimized environments for cultivation. However, unlike agriculture, the application of AI in aquaculture is predominantly focused on diagnosing animal conditions and monitoring them for users. This paper introduces an Automated Fish-feeding System (AFS) based on Convolutional Neural Networks (CNNs) and Gated Recurrent Units (GRUs), aiming to establish an automated system akin to smart farming in the aquaculture sector. The AFS operates by precisely calculating feed rations through two main modules. The Fish Growth Measurement Module (FGMM) utilizes fish data to assess the current growth status of the fish and transmits this information to the Feed Ration Prediction Module (FRPM). The FRPM integrates sensor data from the fish farm, fish growth data, and current feed ration status as time-series data, calculating the increase or decrease rate of ration based on the present fish conditions. This paper automates feed distribution within fish farms through these two modules and verifies the efficiency of automated feed distribution. Simulation results indicate that the FGMM neural network model effectively identifies fish body length with a minor deviation of less than 0.1%, while the FRPM neural network model demonstrates proficiency in predicting ration using a GRU cell with a structured layout of 64 × 48. Full article

Interest in aquaponics (AP) is increasing due to its ability to minimize sewage and maximize feed efficiency in fish farming. However, owing to limitations of intensive cultures and a lack of nutrients such as NO₃ for growing crops, AP requires the use of artificial nutrients. Therefore, novel approaches are required to develop AP-intensive culturing methods. An AP system based on biofloc technology (BFT) called FLOCponics (FP) has been recommended. Here, the productivity of the weather loach (Misgurnus anguillicaudatus) in the FP system, BFT system, and flow-through systems (FTSs), as well as these systems’ effect on Caipira lettuce (Lactuca sativa) growth, was analyzed. To compare crop productivity, a hydroponic (HP) bed was installed. The growth rate of M. anguillicaudatus showed significant differences, at 51.1 ± 3.69% in the FP system, followed by 24.0 ± 4.16% in the BFT system and −14.3 ± 1.4% in the FTS. Its survival rates were better in the FP system (91.1 ± 2.64%) than in the BFT system (82.1 ± 10.98%) or the FTS (66.8 ± 2.75%) (p < 0.05). Total ammonia nitrogen and NO₂⁻-N concentrations were stabilized in every plot during the experimental period. However, the NO₃⁻-N concentration continuously increased in the BFT system but decreased in the FP system and was maintained. The shoot weight of the Caipira lettuce was 163.6 ± 8.65 g in the FP system and 149.6 ± 9.05 g in the HP system. In conclusion, FP system can provide a large amount of nutrients and improve the growth performance of both fish and crops in the FP system. Full article

Aquaponic systems offer an innovative approach to sustainable agriculture, where the interplay between fish and plant cultivation can be optimized. The choice of feeding and fasting schedules plays a crucial role in system efficiency and overall productivity. This study aims to investigate the impacts of various feeding and fasting schedules on water quality, and the growth performance of Nile tilapia, Oreochromis niloticus fingerlings, and spinach productivity in an aquaponic system based on the nutrient film technique (NFT). O. niloticus fingerlings with an initial weight of 13.47 ± 0.14 g were randomly stocked at a density of 6 kg/m³, and spinach plants (Spinacia oleracea) were included. The study employed a completely randomized block design with five replications. Various water quality parameters were monitored, and the effects of different feeding/fasting schedules on fish and spinach were assessed. The data revealed significant differences (p < 0.05) in water quality parameters, all of which remained within acceptable ranges for aquaponic systems. The one-day feeding/one-day fasting treatment resulted in reduced final body weight, weight gain percentage, and specific growth rate, compared to other treatment groups (p < 0.05). Higher levels of glucose and plasma cortisol were observed in this treatment. Economic efficiency was highest in the daily feeding treatment (40.05%), with no statistical difference (p > 0.05) observed in the group subjected to three-day feeding/one-day fasting (39.03%). Spinach yield varied significantly between treatments (p < 0.05), with the daily feeding treatment recording the highest yield (2.78 kg/m²) and the one-day feeding/one-day fasting cycle having the lowest yield (1.57 kg/m²). The findings suggest that the three-day feeding/one-day fasting regime in an NFT-based aquaponic system results in efficient nutrient utilization, higher productivity, and profitability for Nile tilapia. Additionally, this approach supports marketable biomass production for spinach. Different feeding and fasting schedules have distinct effects on water quality, fish growth, and spinach productivity in aquaponic systems. The three-day feeding/one-day fasting schedule emerges as an effective strategy for optimizing resource utilization and increasing overall productivity. Full article

This comprehensive review explores aquaponics as an environmentally friendly solution aligned with SDGs and food sovereignty, assessing various aspects from system design to automation, and weighing social, economic, and environmental benefits through literature and case studies. However, challenges persist in obtaining organic certification and legislative recognition, hindering its growth. Achieving remarkable water use efficiency, up to 90%, relies on adaptable fish species like Nile tilapia and carp. Nutrient-rich fish feeds notably benefit low-nutrient-demanding greens. Ensuring water quality and efficient nitrification are pivotal, supported by IoT systems. Despite its efficiency, integrating Industry 4.0 involves complexity and cost barriers, necessitating ongoing innovation. Economies of scale and supportive horticultural policies can bolster its viability. Aquaponics, known for its efficiency in enhancing crop yields while minimizing water use and waste, is expanding globally, especially in water-scarce regions. Aquaponics, pioneered by the University of the Virgin Islands, is expanding in Europe, notably in Spain, Denmark, Italy, and Germany. Asia and Africa also recognize its potential for sustainable food production, especially in water-limited areas. While it offers fresh produce and cost savings, challenges arise in scaling up, managing water quality, and meeting energy demands, particularly for indoor systems. Egypt’s interest in desert and coastal regions highlights aquaponics’ eco-friendly food production potential. Despite the associated high costs, there is a quest for practical and affordable designs for everyday integration. Research in arid regions and industry advancements are crucial for aquaponics’ global food production potential. Deeper exploration of intelligent systems and automation, particularly in large-scale setups, is essential, highlighting the industry’s promise. Practical application, driven by ongoing research and local adaptations, is a key to fully harnessing aquaponics for sustainable food production worldwide. Full article

The union of aquaculture and hydroponics is named aquaponics—a system where microorganisms, fish and plants coexist in a water environment. Bacteria are essential in processes which are fundamental for the functioning and equilibrium of aquaponic systems. Such processes are nitrification, extraction of various macro- and micronutrients from the feed leftovers and feces, etc. However, in aquaponics there are not only beneficial, but also potentially hazardous microorganisms of fish, human, and plant origin. It is important to establish the presence of human pathogens, their way of entering the aforementioned systems, and their control in order to assess the risk to human health when consuming plants and fish grown in aquaponics. Literature analysis shows that aquaponic bacteria and yeasts are mainly pathogenic to fish and humans but rarely to plants, while most of the molds are pathogenic to humans, plants, and fish. Since the various human pathogenic bacteria and fungi found in aquaponics enter the water when proper hygiene practices are not applied and followed, if these requirements are met, aquaponic systems are a good choice for growing healthy fish and plants safe for human consumption. However, many of the aquaponic pathogens are listed in the WHO list of drug-resistant bacteria for which new antibiotics are urgently needed, making disease control by antibiotics a real challenge. Because pathogen control by conventional physical methods, chemical methods, and antibiotic treatment is potentially harmful to humans, fish, plants, and beneficial microorganisms, a biological control with antagonistic microorganisms, phytotherapy, bacteriophage therapy, and nanomedicine are potential alternatives to these methods. Full article

Stocking density is a key factor affecting the health of aquatic organisms in industrial aquaponics. In this study, Micropterus salmoides were assigned to one of two density groups (160 and 120 fish/m³) for 40 days. The growth performance, intestinal morphology, enzyme activity, and microbial communities were compared between the two density groups. The findings revealed that the higher stocking density condition exhibited an increased weight gain rate and specific growth rate during the developmental phase of the juvenile M. salmoides. Moreover, remarkable increases in villi height, villi width, and muscular layer thickness were observed. Additionally, this elevated stocking density condition also enhanced the activity of intestinal antioxidant enzymes, consequently improving the structural integrity of the intestine and augmenting the digestive and absorptive capacities of the juvenile M. salmoides. With regard to the intestinal microbial community, the dominant phyla detected were Firmicutes and Proteobacteria. However, under the higher stocking density condition, there was a significant upsurge in the abundance of Mycoplasma. Consequently, it is advised to mitigate the abundance of such pathogenic microorganisms through the regulation of the water environment during the aquacultural process. Drawing from recent investigations on the impact of various factors on the intestinal microbiota of M. salmoides, it can be deduced that the composition of the intestinal microbiota is closely intertwined with factors including aquaculture practices, feed composition, water environment, and developmental stage. In summary, the aforementioned research findings possess noteworthy implications for the control of stocking density in the cultivation of juvenile M. salmoides. Full article

Over the years, aquaponics has become a powerful technological tool that allows the sustainable production of food, integrating conventional fish farming with vegetable production. The present study evaluated the production of late seedlings of açai Euterpe oleraceae in an aquaponic system with tambaqui Colossoma macropomum. A total of 36 tambaquis with an initial average weight and length of 1086.75 ± 16.38 g and 38.49 ± 0.90 cm were distributed in 12 independent aquaponic units, totaling 3.62 kg m⁻³. The fish were fed three times daily with commercial feed at a rate of 3%. Three flooding levels of 5, 10 and 15 cm, with constant water flow through the hydroponic bed (0.5 m²), were evaluated, and a control-hydroponic bed with flooding levels of 10 cm was established, all in triplicate. In the 5 and 10 cm treatments, 3450 açai seedlings with an initial height of 12.3 ± 1.9 cm were used (575 per aquaponic units), while the 15 cm treatment contained non-germinated açai seeds. The control group did not receive açai seeds and remained empty. Analyses to monitor total dissolved solids (TDS), electrical conductivity, dissolved oxygen, temperature, pH, alkalinity, hardness, nitrogenous compounds, and phosphate levels were performed. At the end of the 30-day trial, the growth performance of tambaqui and plants was evaluated. Water quality was significantly (p < 0.05) affected by different flooding levels. Electrical conductivity and TDS decreased with an increasing in flooding levels. The flooding levels significantly influenced (p < 0.05) the concentration of total ammonia and nitrate between the treatments. The 5 cm flooding level showed the best plant development indexes for total height, aerial portion height, root height and aerial portion fresh mass. No significant differences (p < 0.05) were observed in tambaqui growth performance. The aquaponic system proved to be effective in reusing fish waste (excreta and feed leftovers) generated in the system. The biotransformation of waste into nutrients allowed the growth of plants and nitrifying bacteria, which, through their metabolic pathways, ensured the purification and reuse of water, avoiding the discharge of this waste into the environment. Full article

Within the modern aquaculture goals, the present study aimed to couple sustainable aquafeed formulation and culturing systems. Two experimental diets characterized by 3 and 20% of fish meal replacement with full-fat spirulina-enriched black soldier fly (Hermetia illucens) prepupae meal (HPM3 and HPM20, respectively) were tested on European seabass (Dicentrarchus labrax) juveniles during a 90-day feeding trial performed in aquaponic systems. The experimental diets ensured 100% survival and proper zootechnical performance. No behavioral alterations were evidenced in fish. Histological and molecular analyses did not reveal structural alterations and signs of inflammation at the intestinal level, highlighting the beneficial role on gut health of bioactive molecules typical of HPM or derived from the enriching procedure of insects’ growth substrate with spirulina. Considering the quality traits, the tested experimental diets did not negatively alter the fillet’s fatty acid profile and did not compromise the fillet’s physical features. In addition, the results highlighted a possible role of spirulina-enriched HPM in preserving the fillet from lipid oxidation. Taken together, these results corroborate the use of sustainable ingredients (spirulina-enriched HPM) in aquaponic systems for euryhaline fish rearing. Full article

In order to further close nutrient cycles of aquaponic systems, it could be possible to integrate a third trophic level in the form of insect larvae production (i.e., black soldier fly larvae) to recycle internal waste streams into valuable nutrients. This would present opportunities to formulate sustainable circular aquafeeds that combine these internally available nutrients with complementary external raw materials. The ingredient composition of feeds for such circular multitrophic food production systems (CMFS) may affect fish performance as well as excretion of important dissolved plant nutrients such as N, P and K. Hence, fish meal from catfish processing (CM) as base ingredient was combined with variable levels of poultry by-product meal (PM) and black soldier fly larvae meal (BSFM) into three marine-ingredient-free experimental diets corresponding to hypothetical production scenarios of a CMFS that aims to integrate aquaponics with insect larvae production. These experimental diets and a commercial diet (COM) were compared using isonitrogenous and isolipidic formulations. They were fed to African catfish (Clarias gariepinus) in recirculating aquaculture systems (RAS) and evaluated concerning growth performance and nutrient excretion. All diets resulted in similar total inorganic nitrogen (TIN) excretion, whereas the increase of dietary PM inclusion from 0% (BSF diet) to 20% (MIX diet) and to 41% (PM diet) and concomitant reduction of BSFM inclusion led to increasingly higher soluble reactive phosphorus (SRP) excretion per unit of feed compared to the COM diet. While the PM diet enabled the best growth and feed conversion performance, the MIX and especially the BSF diet produced more similar performance to the COM diet, which generated the highest dissolved K excretion. The MIX and the PM diet resulted in the highest Ca and P, yet lower N content in the fish feces. Results indicate that combining CM with elevated levels of PM in the diet of African catfish could improve growth performance and reduce the need for P fertilization in aquaponics when compared to industrial diets optimized for low environmental impact. Findings are discussed regarding their implications for CMFS and aquaponic feed formulation. Full article