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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. [ABSTRACT FROM AUTHOR]

Conventional aquaponics conserve water used in aquaponics whereas the literature suggests a certain level of freshwater replenishment or freshwater exchange for good water quality, fish and plant wellbeing, and the overall productivity of the system. This paper deals with the determination of an optimal freshwater replenishment rate for a standard aquaponics system. IoT devices and sensors were used for this project data collection. This paper used linear regressions and ensemble methods to determine the optimal rate of periodic water replenishment to maintain the water quality parameters that determine the yield and productivity of aquaponics systems. Cubic spline and Lagrange interpolation were applied to raw and simulated data. Results were evaluated and compared using statistical error estimation approaches. The bestmodel amongst the investigated machine learning models was gradient boost with an optimal replenishment rate of 19L per week and a water quality of 4.86 for an aquaponic tank of 100 L capacity. The error estimations were a Mean Squared Error of 0.0224, Mean Absolute Error of 0.1137, Root Mean Squared Error of 0.1499, and R2 of 0.7208. This was within 1% of the value obtained fromraw and interpolated data using a polynomial regression. These findings suggest that the water quality of an aquaponics system can be maintained at the desired optimal level with a weekly 19% water replenishment, thereby contributing to the improvement of productivity and resource efficiency. [ABSTRACT FROM AUTHOR]

The article discusses the importance of the Lamiaceae family of plants, which includes species like thyme, mint, oregano, basil, and sage. These plants are known for their aromatic properties and are widely used in various industries such as food, cosmetics, and pharmaceuticals. The article also highlights recent research on topics such as plant cultivation methods, extraction techniques for essential oils, and the preservation of fresh produce using natural compounds. The collection of scientific papers aims to explore the potential of these plants and their extracts in various applications while optimizing growth conditions and extraction methods. [Extracted from the article]

The increasing demand on water resources, reduced land for agriculture, and concerns over food and nutrition security have prompted the evolution of innovative and complex food production systems. In this context, efficient and sustainable food production systems such as aquaponics are viewed as an important and environmentally friendly technology for adaptation under resource-limited environments. Producing food in soilless systems is a promising strategy, as this method utilizes significantly less water than traditional agriculture. However, optimizing growing conditions to enhance crop and fish yields in aquaponics is frequently ambiguous and is often not economically feasible. One of the strategies to improve plant yields and supply of nutrients in aquaponics is the application of probiotics. With this strategy, the crop yields in aquaponics are improved via a variety of mechanisms, including nitrogen fixation, solubilization of mineral nutrients, organic matter mineralization, plant hormone modulation, and biocontrol. As a result, incorporating probiotics in aquaponic systems is a strategy for mitigating environmental effects and advancing sustainable agriculture. This review paper provides the current knowledge of the use of probiotics in aquaponics. Suggestions for further studies on the effects of probiotics in aquaponic systems are proposed. Through literature review, integrating probiotics into aquaponic systems has the potential to improve nutrient supply, modulation of water quality parameters, and microbial communities, which are key processes in enhancing the productivity of aquaponic systems. [ABSTRACT FROM AUTHOR]

Environment changes, water scarcity, soil depletion, and urbanisation are making it harder to produce food using traditional methods in various regions and countries. Aquaponics is emerging as a sustainable food production system that produces fish and plants in a closed-loop system. Aquaponics is not dependent on soil or external environmental factors. It uses fish waste to fertilise plants and can save up to 90–95% water. Aquaponics is an innovative system for growing food and is expected to be very promising, but it has its challenges. It is a complex ecosystem that requires multidisciplinary knowledge, proper monitoring of all crucial parameters, and high maintenance and initial investment costs to build the system. Artificial intelligence (AI) and the Internet of Things (IoT) are key technologies that can overcome these challenges. Numerous recent studies focus on the use of AI and the IoT to automate the process, improve efficiency and reliability, provide better management, and reduce operating costs. However, these studies often focus on limited aspects of the system, each considering different domains and parameters of the aquaponics system. This paper aims to consolidate the existing work, identify the state-of-the-art use of the IoT and AI, explore the key parameters affecting growth, analyse the sensing and communication technologies employed, highlight the research gaps in this field, and suggest future research directions. Based on the reviewed research, energy efficiency and economic viability were found to be a major bottleneck of current systems. Moreover, inconsistencies in sensor selection, lack of publicly available data, and the reproducibility of existing work were common issues among the studies. [ABSTRACT FROM AUTHOR]

Meeting the demand for food through sustainable agro-industrial systems has become a concern due to the current state of the planet's natural resources, population growth, and climate change. To address this, the 2030 Agenda has laid out several strategies to enhance human well-being and protect the planet. This paper focuses on Goal 2, which aims to end hunger, achieve food security, improve nutrition, and promote sustainable agriculture. The first three targets of this goal are as follows: 2.1, ending hunger and ensuring access to nutritious food; 2.2, ending all forms of malnutrition; and 2.3, doubling the agricultural productivity of small-scale food producers. The purpose of this manuscript is to demonstrate how aquaponics can positively impact these three targets by guaranteeing food security through the production of high-quality protein. Aquaponic crops are enriched with organic nutrients from the water they grow in. This not only increases their nutrient content but also their bioactive molecule content, making them excellent for fighting hunger and malnutrition. Moreover, these practices can be adjusted to different scales, making them a viable option for small farmers, women, and rural communities to produce their own food. Consequently, aquaponics can play a crucial role in achieving Zero Hunger locally, with appropriate support. [ABSTRACT FROM AUTHOR]

The food production system 'aquaponics' has moved a long way from its inceptions in the 1970s and 1980s. This paper suggests that it is the principle of aquaponics that should define what aquaponics is and then the rest follows according to systems and technologies. This paper supports the Palm et al. (Aquac Int. 2018;26(3):813–42) position of having a nutrient supply threshold (>50%) from the feed via the aquatic organisms to the plants. We test the most recent alternative definitions (e.g. Baganz et al. Rev Aquac. 2021;14:252–64) that overcomplicate existing definitions and nomenclature. Any new definition needs to be referential to existing terms and properly tested. This paper does exactly that, concluding that several recent changes by Baganz et al. (Rev Aquac. 2021;14:252–64) are not needed. We also debate that the key principle behind aquaponics is 'all about coupling'. Whilst coupling is an important aspect, existing technologies and those that will emerge are far more complex. Finally, this paper highlights the idiosyncrasies in the term aquaponics and we suggest an alternative term 'aquaorganoponics', which in essence better describes the principles of aquaponics (s.s.) which transfers natural organic compounds combined with microbes in water from the aquaculture unit to the plants. [ABSTRACT FROM AUTHOR]

Introduction: Aquaponics provide multiple benefits due to the simultaneous yield of vegetables and fish, however they are characterized by increased greenhouse gas emissions owing to intensive production system. The most appropriate method for quantifying the environmental effects of these systems is Life Cycle Assessment with which the identification of hotspots and the suggestion of improved production plans can be achieved. The purpose of the present study was to evaluate the environmental impact of a pilot high-tech aquaponic system utilized for the simultaneous production of baby lettuce and rocket as well as rainbow trout, in indicators such as Global Warming Potential. Materials and methods: To achieve this goal, data on inputs and outputs were collected from 12 case studies that were implemented, combining different fertilizer treatments, substrate choices, plant species cultivated and water source provision. Life Cycle Assessment was performed using SimaPro v.9.4.0.2 software. Results: The results showcase that the optimal case studies include the cultivation of baby lettuce and rocket in perlite substrate using wastewater from fish and partial use of synthetic fertilizers. Indicatively, Global Warming Potential of these cases was calculated at 21.18 and 40.59 kg CO2-eq/kg of vegetable respectively. The parameter with the greatest impact on most of the environmental indicators was electricity consumption for the operation of the oxygen supply pump for the fish tanks, while greenhouse infrastructure had the greatest impact in Abiotic Depletion and Human Toxicity impact categories. In an alternative production scenario tested where renewable energy sources were used, system impacts were reduced by up to 50% for Global Warming Potential and 86% for Eutrophication impact. The results of this study aspire to constitute a significant milestone in environmental impact assessments of aquaponic production systems and the adoption of more sustainable farming practices. [ABSTRACT FROM AUTHOR]

Indoor farming technologies, such as aquaponics and hydroponics, are crucial for advancing sustainable agriculture, especially in urban areas with limited land for conventional agriculture. As studies comparing these two systems are limited, this study explored the cultivation of five leafy vegetables--white leaf beets (Beta vulgaris var. cicla), hooker chives (Allium hookeri), basil (Ocimum basilicum), lemon balm (Melissa officinalis), and spearmint (Mentha spicata)--in an indoor greenhouse facility using two different food production platforms: an aquaponic system (AS) with catfish (Silurus asotus) and a conventional hydroponic system (HS). The results showed that the plant growth in AS outperformed that in HS, while the general growth patterns in AS were significantly affected by the different light sources. In addition, the leaf yield of the herbal plants (basil and lemon balm) in AS was 60%-70% more than that in HS. The leaf growth of hooker chives in AS also showed significant improvement (200%) compared with that in HS. It appears that the nutrient sources provided by fish were remarkable, as the average concentration of NO3-N (64 mg/L) was easily achieved in AS. The proposed AS, therefore, would be a promising alternative to the production and supply of supplement organic food, ultimately contributing to promoting sustainable agriculture in a changing climate. [ABSTRACT FROM AUTHOR]

Water quality in land-based fish production can be controlled through either instantaneous water exchange or costly wastewater treatment followed by recirculation. Agricultural-aquaculture integration is an excellent alternative technique for reducing nutrient discharge levels, boosting profitability, and converting fish culture wastewater into valuable products. The current study employed a solar energy system to power two separate IMTA-aquaponics systems (Nutrient Film Technique, NFT, and Floating Raft Systems, FRS) for the cultivation of Nile tilapia, African catfish, thin-lipped grey mullet, freshwater crayfish, freshwater mussels, and a variety of vegetables. Tilapia and catfish were fed exclusively on diets under the IMTA system. All wastewater from tilapia and catfish ponds, both dissolved and solid, flows sequentially to ponds containing other cultivated species. The water then flows through the IMTA system's terminal point to the NFT and FRS systems before returning to the tilapia and catfish ponds, allowing complete control of the nutrient flow throughout this entire circular system. Two 147-day production cycles were concluded. The results from the second production cycle are reported. Total biomass gain for aquatic species in the IMTA system was 736.46 kg, compared to 145.49 kg in the tilapia and 271.01 kg in the catfish monoculture systems. The current IMTA system had a cumulative feed conversion ratio (FCR) of 0.90, while the FCRs for tilapia and catfish were 1.28 and 1.42, respectively. Nile tilapia and catfish consumed 571.90 kg of feed containing 25.70 kg of nitrogen (N) and 9.70 kg of phosphorus (P), reflecting, and gaining 11.41 and 3.93 kg of dietary N and P, representing 44.40 and 40.46% dietary N and P retention, respectively. In the IMTA system, the addition of mullet and prawn as detrivores aquatic animals improves dietary N and P utilization efficiency to 59.06 and 51.19%, respectively, while the addition of mussels as herbivore animals improves dietary N and P utilization efficiency to 65.61 and 54.67%, respectively. Finally, using FRS and NFT as hydroponic systems increased dietary N and P efficiency to 83.51% N and 96.82% P, respectively. This study shows that the IMTA-Aquaponic system, as a bio-integrated food production system, can convert the majority of fish-fed residues into valuable products suitable for desert, rural, and urban areas in impoverished and developing countries. [ABSTRACT FROM AUTHOR]

Seasonal factors such as temperature, solar UV-light intensity, and daylight length can induce changes in the water quality properties and, hence, the nutritional compositions of plants. This comparative study was carried out for the consecutive four (4) seasons (winter, spring, summer, and autumn) to determine the influence of seasonal variations on the 50% inhibitory concentration (IC50), total antioxidant capacity (TAC), total phenolics content (TPC), and total flavonoids content (TPC) of the red chili fruit (RCF), red tomato fruit (RTF), green leafy spinach (GLS), and green leafy lettuce (GLL) collected from a coupled commercial aquaponics system. The IC50, TAC, TPC, and TFC concentration levels indicated a significant (P<0.05) difference in the summer compared with the winter, spring, and autumn. The RCF extract indicated the lowest IC50, thus greater scavenging power in comparison to RTF, GLS, and GLL extracts. Similarly, the RCF showed the highest TAC and TPC, while the GLL showed the highest TFC. In this study, variations in seasons have induced changes in the IC50, TAC, TPC, and TFC concentration levels of the RCF, RTF, GLS, and GLL extracts. [ABSTRACT FROM AUTHOR]

The European Union's (EU) agricultural self-sufficiency is challenged by its reliance on imported plant proteins, particularly soy from the Americas, contributing to deforestation and greenhouse gas emissions. Addressing the EU's protein deficit, this study evaluates alternative protein sources for aquaculture, focusing on their nutritional value, elemental content, and polycyclic aromatic hydrocarbons (PAHs). Protein flours from gastropods (Helix pomatia, Arion lusitanicus, Arion vulgaris) and their hepatopancreas, along with plant-based proteins from food industry by-products (oilcakes, coffee grounds, spent brewer's yeast), were analyzed. Results revealed that snail flour contained the highest protein content at 59.09%, significantly outperforming hepatopancreas flour at 42.26%. Plant-based proteins demonstrated substantial nutritional value, with coffee grounds flour exhibiting a remarkable protein content of 71.8% and spent brewer's yeast flour at 57.9%. Elemental analysis indicated high levels of essential minerals such as magnesium in hepatopancreas flour (5719.10 mg/kg) and calcium in slug flour (48,640.11 mg/kg). However, cadmium levels in hepatopancreas flour (11.45 mg/kg) necessitate caution due to potential health risks. PAH concentrations were low across all samples, with the highest total PAH content observed in hepatopancreas flour at 0.0353 µg/kg, suggesting minimal risk of PAH-related toxicity. The analysis of plant-based protein sources, particularly oilcakes derived from sunflower, hemp, flax, and pumpkin seeds, revealed that these by-products not only exhibit high protein contents but present a promising avenue for enhancing the nutritional quality of feed. This study underscores the potential of utilizing gastropod and plant-based by-products as sustainable and nutritionally adequate alternatives to conventional feeds in aquaculture, contributing to the EU's environmental sustainability goals. [ABSTRACT FROM AUTHOR]

The effects of nutrient flows on tilapia fish (Oreochromis niloticus) and plant crops in three model aquaponic systems (deep water culture system, nutrient film technique and substrate beds) placed under identical conditions were evaluated. Quantitative analysis of ammonia, nitrite, nitrate concentrations and the factors on which they depend (air and fish water temperature, air humidity, pH and dissolved oxygen) was performed. The nutrient solutions affecting the yield and quality of the produce and the efficiency of the resources used were assessed. Monitoring and good management of aquaponics are necessary and mandatory requirements to ensure optimal conditions for the symbiosis between fish, beneficial bacteria and plants. [ABSTRACT FROM AUTHOR]

Zero-discharge and low-input aquaponics systems are a promising alternative to the intensive agricultural and aquacultural production systems currently used, ensuring high environmental sustainability. However, new approaches and management practices are needed to increase their productivity to reach the yields of classic production systems. In this context, the present study investigated for the first time the potential of two biostimulants to improve lettuce performance in aquaponics, whether coupled or decoupled, with hydroponics serving as a control. A comprehensive evaluation was conducted to assess the plant functional (focusing on the photosynthetic process evaluation) and growth responses at the whole-plant level. In addition, the nutritional state of the leaves was determined and metabolomic analysis was performed at the cellular level, the latter also for the first time in aquaponics research. The results demonstrated the limitations that coupled aquaponics poses in relation to lettuce growth, function and metabolism, which were already obvious from the 12th day of the experiment. Indicatively, the plants grown under coupled aquaponics exhibited a notable decrease in the leaf fresh weight, potassium content and nitrogen content, with reductions of 80%, 60%, and 30%, respectively, in comparison to the hydroponics control. However, the combined physiological and metabolomic data indicate that these plants down-regulate processes and metabolism to acclimate to low nutrient levels in lettuce leaves rather than experiencing damage. The application of biostimulants did not significantly optimize the plants' performance, though one of them appeared to be effective in improving some aspects of the photochemical efficiency. The decoupled and hydroponics systems resulted in similarly high yields and efficiency in terms of plant function, without any marked contribution from the biostimulants. We conclude that the decoupled aquaponics system has been successful in achieving yields comparable to those of hydroponics, with lower chemical inputs. Future studies should focus on examining other biostimulants in this system to further improve its performance while maintaining its environmental benefits within a circular economy framework. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Aquaculture activities often lead to environmental deterioration due to discharges of nutrient-rich wastewater without treatments. The present study aimed to develop a bio-green floating system (BFAS) to utilize excess nutrients, improve water quality, enhance plant and fish production, and minimize threats of aquaculture effluents. The floating raft system was constructed using water spinach integrated with a substrate (lava rock) to allow the development of biofilm communities, which together with the plants, improved the water quality by nutrient sequestration. Three treatments were employed for 105 days: (1) zero water exchange without BFAS (T1-NCT); (2) water exchange at 5-day intervals without BFAS (T2-PCT); (3) zero water exchange with BFAS (T3-BFAS). Total ammonia removal was significantly (p < 0.05) higher (92.4 ± 1.2%) in T3-BFAS compared to T2-PCT (89.2 ± 0.5%). The percent removal of other nutrients such as unionized ammonia, nitrite, and soluble reactive phosphorus was significantly (p < 0.05) higher in T3-BFAS compared to T2-PCT and the control. The T3-BFAS showed a significantly (p < 0.05) lower feed conversion ratio (FCR, 1.16 ± 0.05), higher (p < 0.05) specific growth rate (SGR, 3.58 ± 0.03), and better health indicators (hemato-biochemistry characteristics) compared to the other treatments. Heavy metals in T3-BFAS were significantly lower (p < 0.05) than the control and were significantly higher in roots than in the water. The findings suggested that the simple newly developed energy-free BFAS could enhance water quality, improve fish health, and optimize fish production in an aquaculture system without water exchange. [ABSTRACT FROM AUTHOR]

This research aimed to standardize the growth of two commonly cultivated herbs in the United Arab Emirates, basil (Ocimum basilicum L.) and coriander (Coriandrum sativum L.), within an aquaponic system. The study compared a recirculatory aquaponic system (RAS) with static aquaculture systems (for fish performance) and irrigated greenhouse cultivation systems (for herb performance). The project assessed growth, element composition, and aquaponic efficacy to determine the viability of aquaponics for these herbs. In the soilless (aquaponic) system, both herbs exhibited significantly enhanced growth parameters, including plant height, root length, leaf count, and fresh and dry weights, compared to conventional soil‐based cultivation. This growth enhancement was attributed to the additional nutrients derived from fish waste in the aquaponic system. Furthermore, plants displayed significantly higher element levels, highlighting the effectiveness of aquaponics in nutrient delivery. Notably, the aquaponic system demonstrated superior antioxidant activity in both herbs. The study also revealed remarkable water use efficiency in the aquaponic system, with water savings exceeding 90% compared to conventional methods. These findings establish the efficiency and sustainability of aquaponic systems over traditional food production approaches, particularly in arid regions such as the United Arab Emirates. Utilizing an aquaponic system for these commonly cultivated herbs resulted in improved growth and resource efficiency, affirming its viability as an environmentally sustainable and efficient method of food production in desert climates. [ABSTRACT FROM AUTHOR]

As the demand for high-quality food rises, especially amidst the COVID-19 pandemic and the continuous development of society meaning that people demand to eat well, ensuring food security has become increasingly urgent. Agricultural technology is evolving, with aquaponic systems emerging as a promising solution to urban food needs. However, these systems present challenges, such as maintaining optimal water quality and minimizing environmental control errors. In this study, we propose a comprehensive approach combining a literature review and controlled experiments. Through the literature review, the recent findings on water management and sustainability in food production were analyzed, providing crucial insights for enhancing aquaponic system performance. Building on this, a series of experiments were conducted to develop and test a water quality management system using PID control. The integration of PID control showed good performance and reduced errors in SIMULINK, and we applied three controls to manage the stability and responsiveness of the aquaponic system. The optimal values obtained from the controller of the vegetable tank system were 4,706,691,503 and −174.418; for the fish tank, they were 36,167, 0.00126, and −174.418; and for the heater system, they were 4.761, 0.0488, and −31.88. This solution is expected to be responsive and provide stable control over various variables. [ABSTRACT FROM AUTHOR]

Societal Impact Statement: Refining circular multitrophic food production methods, which integrate plant, fish, and insect outputs, is imperative for environmental sustainability. Our findings suggest that the right protein choices in fish feed, like black soldier fly meal and poultry meal, can notably enhance the nutrient profile of fish waste water. This, in turn, is conducive for hydroponic cultivation, enhancing the nutritional attributes of plants like basil and lettuce. As we reduce environmental impact and optimize resource use, it is evident that our food ecosystems are deeply intertwined. Harnessing these synergies could redefine our approach to food production, paving the way for a more sustainable global future. Summary: Optimization of nutrient use efficiencies in circular multitrophic food production systems (i.e., plant, fish, and insect production) is crucial for sustainability. This study tested how protein ingredient choice in fish feed influences the plant nutritional value of the fish waste water when used for hydroponic crop production.Waste water samples were obtained from recirculating aquaculture systems (RAS) in which Nile tilapia (Oreochromis niloticus) were fed different single protein source diets—black soldier fly meal (BSFM), poultry by‐product meal (PM), poultry blood meal (PBM), and fish meal. Water was analyzed for plant nutrients and used for lettuce and basil cultivation to evaluate their suitability for hydroponic crop production—viz. yield, mineral nutrient, and selected secondary metabolite levels.BSFM RAS water had the highest concentrations of K, Mg, and micronutrients (Cu, Mn, Mo, Zn) of the RAS waters, whereas PM RAS water contained the highest P concentration and had a mean pH of 6.5 closer to the optimum pH for hydroponic plants. These RAS waters consequently lead to the highest yields in basil and lettuce indicating the importance of the aforementioned factors.From a plant production perspective, BSFM appears promising as a protein source in fish feeds for aquaponics. Usage of RAS waters for plant production helps reduce (i) environmental impact of RAS water and (ii) resource input in plant production. Longer term RAS trials should be conducted to determine the maximum nutrient concentrations achievable during fish production with diets including BSFM as the main protein source. [ABSTRACT FROM AUTHOR]

Environment changes, water scarcity, soil depletion, and urbanisation are making it harder to produce food using traditional methods in various regions and countries. Aquaponics is emerging as a sustainable food production system that produces fish and plants in a closed-loop system. Aquaponics is not dependent on soil or external environmental factors. It uses fish waste to fertilise plants and can save up to 90–95% water. Aquaponics is an innovative system for growing food and is expected to be very promising, but it has its challenges. It is a complex ecosystem that requires multidisciplinary knowledge, proper monitoring of all crucial parameters, and high maintenance and initial investment costs to build the system. Artificial intelligence (AI) and the Internet of Things (IoT) are key technologies that can overcome these challenges. Numerous recent studies focus on the use of AI and the IoT to automate the process, improve efficiency and reliability, provide better management, and reduce operating costs. However, these studies often focus on limited aspects of the system, each considering different domains and parameters of the aquaponics system. This paper aims to consolidate the existing work, identify the state-of-the-art use of the IoT and AI, explore the key parameters affecting growth, analyse the sensing and communication technologies employed, highlight the research gaps in this field, and suggest future research directions. Based on the reviewed research, energy efficiency and economic viability were found to be a major bottleneck of current systems. Moreover, inconsistencies in sensor selection, lack of publicly available data, and the reproducibility of existing work were common issues among the studies.

Chlorophyll content reflects plants' photosynthetic capacity, growth stage, and nitrogen status and is, therefore, of significant importance in precision agriculture. This study aims to develop a spectral and color vegetation indices-based model to estimate the chlorophyll content in aquaponically grown lettuce. A completely open-source automated machine learning (AutoML) framework (EvalML) was employed to develop the prediction models. The performance of AutoML along with four other standard machine learning models (back-propagation neural network (BPNN), partial least squares regression (PLSR), random forest (RF), and support vector machine (SVM) was compared. The most sensitive spectral (SVIs) and color vegetation indices (CVIs) for chlorophyll content were extracted and evaluated as reliable estimators of chlorophyll content. Using an ASD FieldSpec 4 Hi-Res spectroradiometer and a portable red, green, and blue (RGB) camera, 3600 hyperspectral reflectance measurements and 800 RGB images were acquired from lettuce grown across a gradient of nutrient levels. Ground measurements of leaf chlorophyll were acquired using an SPAD-502 m calibrated via laboratory chemical analyses. The results revealed a strong relationship between chlorophyll content and SPAD-502 readings, with an R 2 of 0.95 and a correlation coefficient (r) of 0.975. The developed AutoML models outperformed all traditional models, yielding the highest values of the coefficient of determination in prediction ( R p 2 ) for all vegetation indices (VIs). The combination of SVIs and CVIs achieved the best prediction accuracy with the highest R p 2 values ranging from 0.89 to 0.98, respectively. This study demonstrated the feasibility of spectral and color vegetation indices as estimators of chlorophyll content. Furthermore, the developed AutoML models can be integrated into embedded devices to control nutrient cycles in aquaponics systems. [ABSTRACT FROM AUTHOR]

Aquaponics is an environment-friendly system that combines fish and plant crop farming together. The goal of the study was to ascertain the effects of Epsom salt on the growth of water spinach and tilapia in media-based and nutrient film technique (NFT) of aquaponics systems. The Epsom salt was applied to the leaves (T1) at 5% and the roots (T2) at 373 kg/ha fortnightly, while T3 was the control. Water spinach seeds were planted in media beds, and tilapia were stocked in fish tanks at a density of 3.55 ± 0.51 kg/m3. Fish were fed commercial floating pelleted feed with a 30% protein content at the rate of 3% body weight twice daily. Fish growth and water quality parameters were measured periodically. The result interpretation showed that the highest mean length and weight gain, specific growth rate, and fish production were found in T2, where the food conversion ratio (FCR) was the lowest (1.43 (± 0.02)). The control (T3), in comparison, showed a higher FCR (2.02 (± 0.12)) and lower values for all growth parameters, with the exception of fish survival. The T1 in the media bed system had the tallest plants (79.33 ± 7.02 cm), whereas the T2 had the longest and heaviest roots. However, in the NFT system, T1 had the highest water spinach output, followed by T2 and T3, indicating that Epsom salt in the NFT system functioned better in water spinach production than in the media bed system. To optimize the Epsom salt dose in both NFT and media bed aquaponics systems, more research is needed. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The Feeding Mars study was devised as a small, pilot proof of concept study to research the potential for using aquaponic effluents as an additive to regoliths which on Mars and the Moon are devoid of organic material and thus lacking microbes which assist in the delivery of water and nutrients to the plants via their roots. This research investigates aquaponics as a way to potentially produce fish and vegetal products in regoliths on Mars and the Moon as well as in extreme environments on Earth. In order to settle on Mars, settlers will have to grow their own food in systems that are self-perpetuating, with little or no inputs being brought from Earth once these systems have been established. This means that nutrients from the fish water can be used to grow plants in the hydroponic parts of the aquaponic system but also potentially in the Martian regoliths which are treated with effluents taken from aquaponic systems. Once production is established additional nutrients can be sourced from the arisings and waste, both from the fish (that are processed and eaten) and the plants, which can be used as compost to turn the regoliths into soil. In order to have fish in space, there is also the need for the systems to be self-sustaining in the production of fish feed. The key outcomes of the project were that all the species grown (potatoes, tomatoes, dwarf beans, carrots, lettuce, spring onions, chives and basil) indicate the potential to be grown in regoliths with the addition of aquaponic effluents. A significant result was that on the whole the plants that were grown with the addition of aquaponic effluents were greener than those grown in the horticultural soil, indicating that the nutrient supply was adequate. However, a key lesson learned is that germination and thus development of the plants grown in the Mars simulant and analogue was slower than those grown in the horticultural soil. Thus, developing nutrients in the soil before planting is necessary as it is with agriculture and horticulture practices on Earth, where manuring/fertilization occurs before planting. The consequence of this research, and the envisaged research to follow is not only for extra-terrestrial environments. The Earth has its own hostile environments, characterised with regoliths and other unproductive soils, and aquaponic water and aquaponic wastes can readily be envisaged as providing solutions to growing nutritious food in areas where agriculture is not currently viable. The research was undertaken in an exhibition gallery setting at the University of Greenwich in order to encourage public interest and dialogue, which it did. [ABSTRACT FROM AUTHOR]

The need to improve the methods of growing plants in hydroponic systems to ensure optimal conditions for their growth and achieve high yields is urgent. The purpose of this study was to compare the hydroponic production of Lactuca sativa Batavia Aficion using a conventional Knop nutrient solution compared to aquaponics using nutrient-rich fish water. Laboratory, potentiometric, and photometric methods were used for this purpose. The yield, biometric, and qualitative indicators of lettuce leaves were investigated. Despite the lower nutrient concentration in the aquaponic solution, the nutritional status of Lactuca sativa Batavia Aficion was within the optimal range. The nitrate content of lettuce grown in the aquaponics system was higher than in hydroponics, but there were no significant differences in the content of total N (3.24% and 2.97%), Mg (1,973 mg/kg and 1,943 mg/kg), Fe (93.91 mg/kg and 93.83 mg/kg), K (73.7 mg/kg and 73.6 mg/kg), and Ca (19.5 mg/kg and 20.1 mg/kg). The yield of Lactuca sativa Batavia Aficion on aquaponics was 2.8 kg/m² and 3.2 kg m² - on hydroponics, with a density of 36 plants per square metre. Water monitoring in the aquaponic system showed low concentrations of nitrates, phosphorus (P), potassium (K), and magnesium (Mg), but the proportion of mineral nutrients and pH were stable throughout the lettuce growing period. Lettuce leaves in the aquaponics system reached a fresh weight of 80 g in 34 days, which is on average 13% less than lettuce leaves in the hydroponics system. The EC (electrical conductivity) values recorded in this study in a hydroponic system were between 1.2 and 1.5 cm/m. In the aquaponic system, EC has higher values due to the low rate of water replacement, contributing to greater growth and accumulation of solution ions. However, due to continuous recirculation in the water, the conditions become satisfactory for growing plants. The results obtained can contribute to the creation of more efficient and sustainable agricultural systems, reducing resource consumption and improving the resistance of cultivated crops to various stressful conditions [ABSTRACT FROM AUTHOR]