Search Results (36)

Brackish aquaponics is expected to be a promising approach to sustainable food production, integrating saline water resources with simultaneous co-cultivation of fish and halophytes. The present study investigated the effects of three feeding ratios (FR1.5: 1.5%, FR3: 3%, and FR6: 6% b.w/d) on the growth performance of European sea bass (Dicentrarchus labrax) and glasswort (Salicornia europaea) co-cultured in three autonomous one-loop recirculation aquaponic systems (180 L each) at 20 ppt salinity over 78 days. Each system comprised three fish-rearing tanks connected to a two-stage sump filter and a nutrient film technique (NFT) hydroponic subsystem. Sea bass fed at FR3 achieved significantly higher weight gain, specific growth rate, and feed conversion efficiency than FR1.5. At FR6, feed consumption nearly doubled compared to FR3 (3.79 vs. 1.91 g), yet the feed conversion ratio increased from 0.79 to 1.65, and protein efficiency ratio declined from 3.80 to 1.91, indicating overfeeding effects. Regarding glasswort, FR6 produced significantly higher chlorophyll a content and plant biomass, whereas FR1.5 showed superior ammonia removal efficiency. Overall, FR3 provided the best balance between fish growth, plant yield, and water quality maintenance. These findings highlight the critical role of feeding management in brackish aquaponics in order to optimize nutrient coupling between fish and halophyte production. Full article

As the global population continues to rise, sustainable agricultural systems such as aquaponics have gained attention for their potential to maximize food production while minimizing resource use. This study evaluated the growth performance, yield, and mineral composition of okra (Abelmoschus esculentus) grown in a coupled aquaponic system with Nile tilapia (Oreochromis niloticus), comparing two production methods: floating raft and flooded media bed. Okra was cultivated at two planting densities (32 and 48 plants/m²) over a 12-week period, and multiple plant growth parameters and tissue mineral compositions were assessed at harvest. Results showed that plant production method significantly (p < 0.05) influenced okra growth and yield, while planting density had limited impact. Okra grown in media beds exhibited greater (p < 0.05) stem length, stem and root weights, number of leaves, and okra (fruit) production compared to those grown on floating rafts. Although root length was longer (p < 0.05) in raft-grown plants, root biomass was notably higher (p < 0.05) in plants grown in media beds. Mineral composition of plant tissues also varied with production method and density. Media-grown okra generally had higher (p < 0.05) concentrations of calcium, phosphorus, and copper in leaves and stems, whereas raft-grown plants showed elevated levels of sodium and zinc in several tissues. Plant density affected a few specific mineral concentrations, particularly in roots and fruit, though effects were inconsistent. While fish growth was not high, possibly due to some water quality parameters (such as alkalinity and hardness) not being optimal, plant performance in media beds without supplemental nutrient inputs highlights the viability of fired clay media in aquaponic okra production. These findings suggest that media beds offer agronomic advantages over floating rafts for okra cultivation in aquaponic systems, with implications for optimizing nutrient delivery and plant health in sustainable food production systems. Full article

This study evaluated the performance of lettuce (Lactuca sativa) cultivated in coupled aquaponic systems integrated with Nile tilapia (Oreochromis niloticus) and African catfish (Clarias gariepinus) under tropical greenhouse conditions. The experiment was conducted across two consecutive lettuce production cycles to assess fish growth, plant performance, water quality, and nutrient dynamics. African catfish exhibited significantly higher specific growth rates (1.08 ± 0.18%/day; p = 0.02) and weight gain (92.38 ± 22.29%; p = 0.03) compared with tilapia. During the first lettuce cycle, tilapia-based systems yielded significantly higher final plant weights (177.6 ± 34.4 g/plant; p = 0.0002), and greater increases in leaf number, weight gain, and absolute growth rate than catfish-based systems. However, in the second cycle, catfish systems resulted in superior lettuce leaf morphology, with significantly greater leaf length, width, and total leaf area. Nutrient profiles differed markedly between systems. In the deep-water culture (DWC) units, total phosphorus (TP) concentrations were significantly higher in the tilapia-based system during cycle 1 (12.39 ± 0.64 mg/L; p = 0.0001), while total nitrogen (TN) concentrations were significantly higher in the catfish treatment during cycle 2 (21.54 ± 2.93 mg/L; p = 0.0007). Catfish-based systems also showed higher levels of calcium and sodium. Despite these differences, temperature, pH, and dissolved oxygen remained within optimal ranges for aquaponic production across both systems. Overall, tilapia-based aquaponics promoted faster early-cycle plant growth and higher initial yield, whereas catfish-based systems enhanced nitrogen availability and improved lettuce leaf structural development over successive cycles. These findings indicate that fish species selection plays a critical role in shaping nutrient dynamics and crop performance in tropical aquaponic systems. Full article

Aquaponics consists of the combination of hydroponics and aquaculture within a closed loop, being a promising technology for food production and wastewater treatment in the context of the circular economy. This technology is less energy-intensive, environmentally friendly, and consumes less water. In addition, the wastewater produced by fish, rich in nutrients, can be used to grow a wide variety of plants, which avoids further treatments for nutrient removal. Although aquaponics presents advantages from an environmental point of view with regard to other technologies, its sustainability must be analyzed using systematic tools, such as the Life Cycle Assessment (LCA). In this work, a small-scale aquaponics system (tilapia–lettuce) coupled with a photovoltaic unit was designed and assessed from an environmental perspective using the LCA to quantify its environmental burdens. The photovoltaic unit was sized to supply renewable energy to the system, achieving a reduction of 52% in grid electricity consumption. The environmental impacts of the system were quantified by the LCA, showing that electricity and fish feed were the most important contributors to all the impacts (by 90%), obtaining significant reductions (by 40% on average for all of them) when coupling a photovoltaic unit to the system. Full article

Aquaponics is a water-reusing, circular form of controlled-environment agriculture, but its sustainability benefits depend on reliable, constraint-aware nutrient dosing under delayed inflow effects. Aquaponics involves coupling hydroponics with aquaculture but is difficult to control because the greenhouse/crop state at the current time step ($t$) must anticipate water-quality changes that arrive at the next time step ($t+1$), under hard EC–pH and dose constraints. We propose the Analysis System for Nutrient Requirements in Hydroponics (ASNRH), a two-module, constraint-aware framework that directly regresses next-step elemental supplementation (N, P, K; mg·L⁻¹). First, the Fish-farm By-product Prediction Module (FBPM) uses a lightweight GRU forecaster to predict inflow chemistry at $t+1$ (e.g., NH₄⁺/NO₂⁻/NO₃⁻, alkalinity) from standard aquaculture sensors. Second, the Nutrient Requirement Prediction Module (NRPM) encodes the current hydroponic and crop state at t in parallel with the FBPM inflow at $t+1$ via a dual-branch architecture and fuses both representations to produce non-negative dose recommendations while penalizing forecasted EC/pH violations and excessive actuation volatility. The data pipeline assumes low-cost greenhouse and aquaculture sensors with chronological, leakage-free splits. A protocol-first simulation evaluates ASNRH against time-series and rule-based baselines using accuracy metrics (MAE/RMSE/R²), EC/pH violation rates, and robustness under missingness/noise; ablations isolate the contributions of the inflow branch, constraint-aware losses, and lightweight physics priors. The framework targets deployability in decoupled or coupled aquaponics by structurally resolving $t$ vs. $t+1$ asynchrony and internalizing domain constraints during learning; procedures are specified to support reproducibility and subsequent field trials. By operationalizing anticipatory dosing from reused aquaculture byproducts under EC/pH feasibility constraints, ASNRH is designed to support sustainability goals such as reduced nutrient wastage and fewer corrective water exchanges in coupled or decoupled aquaponics. Full article

One major bottleneck for the sustainable development of the aquaculture sector is the reliance on conventional feed ingredients, such as fishmeal and soy protein. Another challenge is nutrient loss from these systems, which contributes to environmental pollution but also represents a waste of valuable resources. To make aquaculture truly sustainable, a shift toward circular, sustainable systems is necessary. This study compared a regionally available alternative feed, based on blue mussel meal and pea protein concentrate, to a conventional fish meal and soybean control diet in Nile tilapia (Oreochromis niloticus) reared in coupled aquaponic systems. Fish performance and stress levels, water quality, plant growth, and microbial quality were investigated. Growth performance and feed intake were similar between aquaponic and control recirculating aquaculture systems (RASs) during the control feed (CF) phase. Only the feed conversion ratio (FCR) was slightly lower in the aquaponic system during the mussel-pea feed (MPF) phase. Tatsoi (Brassica rapa) growth in the aquaponic systems was comparable to, or even greater than, that of the hydroponic control systems, throughout the experiment, especially during the MPF phase. In addition, the MPF had a positive impact on phenotypic parameters and contributed to enhanced shoot growth. However, the presence of pathogens with potential biohazard impacts on human and fish health remains a concern and warrants further investigation. In our study, Salmonella spp. was detected in both systems, but levels were considerably reduced with the MPF phase. In contrast, Escherichia coli was detected only in RASs and was absent from aquaponic systems. Overall, the findings support the potential of blue mussel and pea protein as sustainable, local feed components in integrated aquaponic production, contributing to nutrient circularity and reducing dependence on limited marine stocks and imported resources. Full article

Stocking density is a key driver of performance in aquaponics, affecting both fish welfare and crop yield. This study evaluated the impact of three initial stocking densities (3.1, 4.1, and 6.2 kg/m³) on survival, growth, feeding behavior, carcass and filet quality of largemouth bass (Micropterus salmoides), as well as on the yield of lettuce (Lactuca sativa), sweet basil (Ocimum basilicum), and Swiss chard (Beta vulgaris var. cicla) cultivated in vertical coupled aquaponic units. A total of 184 fish (109 ± 28 g) were reared for 176 days in nine independent recirculating systems. Fish reared at the lowest density achieved the highest final live weight and specific growth rate, with a better feed conversion ratio, whereas performance declined at higher densities despite similar survival rates. Feeding behavior was generally consistent across groups, although feed intake rate was reduced at the highest density. Carcass and filet quality traits were unaffected by stocking density. Vegetable yield was enhanced by higher fish biomass, with significant increases in lettuce production and a positive trend for basil. These findings indicate that intermediate stocking densities may represent the most sustainable compromise, ensuring fish welfare and acceptable growth while supporting efficient plant production in largemouth bass–based aquaponics. Full article

Bioponics is a promising agricultural system designed to integrate circular economy principles by recovering nutrients from organic waste. In this context we implemented a tri-trophic circular system, where insect larvae fed on crop residues and fruits were processed into insect meal for fish feed. The water used in fish rearing then irrigated tomato crops in an aquaponic setup, closing the nutritional loop. Tomato was cultivated in this system with the aim of thoroughly evaluating its applicability via assessing the dynamics of growth, yield, and functional responses of the crop across three treatments: coupled aquaponics (CAP), decoupled aquaponics (DCAP), and hydroponics (HP, as control). DCAP matched HP in all parameters assessed and even outperformed it in fertilizer use efficiency by 31%. In contrast, CAP showed reduced growth and yield (by 38%) and limitations in photochemical efficiency and photosynthetic performance, likely due to significant deficiencies in potassium and phosphorus (9-fold and 2-fold lower than in HP, respectively). DCAP demonstrated strong potential to achieve similar crop outcomes to conventional hydroponics with enhanced resource efficiency. Overall, adopting the DCAP variant of aquaponics in this circular nutrition system is a promising alternative to conventional hydroponics, supporting a transition toward more environmentally resilient farming practices. Full article

A circular tri-trophic system integrating aquaponics, i.e., combined cultivation of crops and fish, with insect rearing is presented for lettuce cultivation. The nutrition cycle among crops, insects and fish turns waste into resource, thereby increasing the sustainability of this food production system. A comprehensive evaluation of the system’s efficiency was performed, including the growth, functional and resource use efficiency traits of lettuce, the dynamics of which were followed in a pilot-scale aquaponics greenhouse, under three treatments: conventional hydroponics (HP) as the control, coupled aquaponics (CAP) with crops irrigated with fish-derived water, and decoupled aquaponics (DCAP), where fish-derived water was amended with fertilizers to reach the HP target. The main findings indicate comparable physiological performance between DCAP and HP, despite the slightly lower yield observed in the former. The CAP treatment exhibited a significant decrease in biomass accumulation and functional impairments, which were attributed to reduced nutrient levels in lettuce leaves. The DCAP treatment exhibited a 180% increase in fertilizer use efficiency compared to the HP treatment. We conclude that the tri-trophic cropping system with the implementation of DCAP variant is an effective system that enables the combined production of crops and fish, the latter being fed with sustainably derived insect protein. The tri-trophic system improves the environmental impact and sustainability of lettuce production, while making circularity feasible. Full article

The global demand for local and high-quality food sources has increased in recent decades, driven by consumer preferences and a growing population. RAS, hydroponics and a ‘hybrid’ version, aquaponics, are food production techniques that could support such growing demand. The current study evaluated coupled aquaponics (Jade perch and lettuce) with and without mineral supplementation in comparison to standard cultivation methods, i.e., RAS and hydroponics. The mineral supplementation in aquaponics was carried out using a hydroponics commercial blend fertilizer (10% of the dosage utilised in the hydroponics treatment). Fish/plant performance, nutrient dynamics and water quality were evaluated for 9 weeks using twelve experimental units (~720 L in total; fish tank/reservoir + filtration systems/sump + floating raft-based plant tank). After two crops of plants, the results showcased the positive impact of mineral supplementation in aquaponics; however, the hydroponics treatment outperformed the two aquaponics treatments, e.g., with higher total plant wet weight and total plant length (p < 0.05). Fish in aquaponics with and without mineral supplementation presented similar growth performance as compared to RAS (p > 0.05). By comparing these different farming approaches, this study sought to provide insights into optimising aquaponics systems and advancing the integration of Jade perch into aquaculture practices. Full article

Nutrient management in coupled aquaponic systems presents significant challenges due to competing requirements between fish and plant production within a single-loop framework. These challenges often result in suboptimal nutrient concentrations, compromised system efficiency, and reduced yields. This critical review examines the Decoupled recirculating aquaponics system (DRAPS) as an innovative solution that separates fish and plant nutrient cycles while maintaining water recirculation benefits. This study provides a comprehensive review of DRAPS, emphasizing how its decoupled structure enhances nutrient management and promotes sustainable production. It specifically evaluates the ability of DRAPS to optimize macronutrient and micronutrient levels, control agronomic factors independently, and improve both nutrient and water use efficiency. Additionally, this review highlights the advantages of using urea as a nitrogen source, which can enhance plant productivity without compromising fish health. The findings indicate that the loops of DRAPS facilitate customized nutrient concentrations, fostering optimal growth conditions for both plants and fish. By safely incorporating urea as a nitrogen source, DRAPS increases plant productivity while reducing the risk of ammonia toxicity for fish. Furthermore, independent control over agronomic factors enhances nutrient uptake, nutrient use efficiency, and water use efficiency. This approach minimizes the risks of cross-toxicity and enables higher levels of essential micronutrients, such as iron and nickel, which are beneficial for plant health but can be toxic in coupled systems. DRAPS signifies a significant advancement in sustainable agriculture, particularly in regions with limited water and land resources. By optimizing nutrient management and supporting the high-density production of plants and fish, DRAPS presents a scalable, resource-efficient model that aligns with sustainable development goals. Its capacity for precise nutrient control with minimal environmental impact positions it as a valuable solution for sustainable, high-yield food production in resource-constrained settings. Full article

Fertigation practices in soilless crop cultivation often rely on predetermined recipes, which may lead to suboptimal nutrient concentrations due to inherent human error or environmental fluctuations. To address this challenge, the integration of in situ real-time nutrient analyzers becomes imperative for ensuring the delivery of high-quality supply solutions. This study assesses the effectiveness of a real-time nitrate (NO₃⁻) analyzer in optimizing the mineral composition of the nutrient solution for fertigating a decoupled aquaponic cucumber crop. The analyzer was integrated into the programmable logic controller of the greenhouse’s hydroponic system. The NO₃⁻ analyzer was activated during solution preparation, dynamically adjusting the NO₃⁻ concentration based on real-time measurements from either the aquaculture or drainage solution by adding the necessary water or/and nutrients in order to prepare a solution to meet the needs of the crop. Four treatments were evaluated: hydroponics (HP), coupled aquaponics (CAP), decoupled aquaponics (DCAP) with EC adjustment, and decoupled aquaponics with NO₃⁻ adjustment (DCAP_N). Results indicated that the DCAP_N treatment, with NO₃⁻ adjustment, yielded the highest crop productivity, outperforming DCAP, HP, and CAP treatments by 7.4%, 21.2%, and 56.1%, respectively. Additionally, DCAP_N demonstrated superior water use efficiency (WUE) and fertilizer use efficiency (FUE), exhibiting a 21.5% and 52.5% increase over the HP treatment, respectively. These findings align with the European Green Deal’s objectives by enhancing nutrient management practices, which are crucial for minimizing nutrient loss and ensuring the sustainable and efficient use of fertilizers. 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 combined production of three varieties of lettuce (romaine, iceberg, and red leaf) with flathead grey mullet (Mugil cephalus) was tested in triplicate in three independent coupled aquaponic units with no thermal control. For this purpose, a total of 114 fish (2.5 kg/m³) were stocked in each fish tank (2 m³), and 92 lettuces were planted in the hydroponic unit (6 m²). As no thermal control was included in the design of the aquaponic system, water temperatures declined from maximum values of 20.4 °C to minimum values of 5.0 °C, which directly affected fish growth. However, the conditions imposed by the aquaponic system were suitable for promoting lettuce’s growth and external appearance, as no pests or leaf discoloration were noticed. Lettuce survival was similar among the three tested varieties (98.5 ± 1.7%). The yields for the romaine and iceberg varieties were 384 ± 100 g/lettuce and 316 ± 70 g/lettuce, respectively, and that for the red leaf variety was lower, at 176 ± 75 g/lettuce. Yield values ranged between 3.6 and 4.4 kg/m² depending on the replicate considered (4.0 ± 0.4 kg/m²). According to present results, each aquaponic unit required ca. 2.6–2.7 L of water per unit of lettuce produced. Full article

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. Full article