Search Results (51)

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

Aquaculture has emerged as a sustainable alternative to meet the growing demand for aquatic products while preserving natural ecosystems. This study presents the design, simulation, and experimental validation of an intelligent multivariable control system for aquaculture tanks aimed at cultivating Mugil incilis, a native species of the Colombian Caribbean. The system integrates three control strategies: a classical Proportional-Integral-Derivative (PID) controller, a fuzzy logic–based PID controller, and a neural network predictive controller. All strategies were evaluated in simulation using a third-order transfer function model identified from real pond data. The fuzzy PID controller reduced the mean squared error (MSE) by 66.5% compared to the classical PID and showed faster settling times and lower overshoot. The neural predictive controller, although anticipatory, exhibited high computational cost and instability. Only the fuzzy PID controller was implemented and validated experimentally, demonstrating robust, accurate, and stable regulation of potential hydrogen (pH), dissolved oxygen, and salinity under dynamic environmental conditions. The system operated in real time on embedded hardware powered by a solar kit, confirming its suitability for rural or off-grid aquaculture contexts. This approach provides a viable and scalable solution for advancing intelligent, sustainable aquaculture practices, particularly for sensitive native species in tropical regions. Full article

The deterioration of the water environment in small towns in China due to urbanization has posed a significant challenge to their socioeconomic sustainability. Therefore, this study aims to employ an integrated assessment method based on the principal component analysis–minimal water quality index model (PCA–WQI_min) to objectively evaluate the water quality and analyze the pollution characteristics of Wangwenzhuang in Tianjin, thereby providing a scientific basis and decision-making support for the sustainable development of small towns. This study’s findings reveal that the PCA–WQI_min method identified four key water quality parameters essential for a comprehensive assessment of water quality across seasonal and spatial variations. The analysis revealed that the water quality in the investigated region remained at a “poor” level, with relatively consistent levels across the four catchments, ranked from poorest to best as the Xingchilong catchment area (29.61) < Jianxinpaigan catchment area (31.03) < Chilong catchment area (32.94) < Machangjian catchment area (39.61). This study revealed that the average WQI_min values slightly increased in the wet season relative to those in the dry season. This research highlights the critical importance of effectively managing domestic rural sewage and aquaculture pollution to increase surface water quality in small towns. Pollution prevention policies and multiple sources of pollution evaluation will be considered the focus of future studies. Full article

This review aims to study the applications of sensors for monitoring and controlling the physicochemical parameters of water in aquaculture systems such as Biofloc Technology (BFT), Recirculating Aquaculture Systems (RASs), and aquaponic systems using IoT technology, as well as identify potential knowledge gaps. A bibliometric analysis and systematic review were conducted using the Scopus database between 2020 and 2024. A total of 217 articles were reviewed and analyzed. Our findings indicated a significant increase (74.79%) in research between 2020 and 2024. pH was the most studied physicochemical parameter in aquaculture, analyzed in 98.2% of cases (sensors: SEN0169, HI-98107, pH-4502C, Grove-pH), followed by temperature (92.9%, sensor DS18B20) and dissolved oxygen (62.5%, sensors: SEN0237, MAX30102, OxyGuard DO model 420, ZTWL-SZO2-485, Lutron DO-5509). Overall, water monitoring through the implementation of IoT sensors improved growth rates, reduced culture mortality rates, and enabled the rapid prediction and detection of atypical Total Ammonia Nitrogen (TAN) levels. IoT sensors for water quality monitoring in aquaponics also facilitate the evaluation and prediction of seed and vegetable growth and germination. In conclusion, despite recent advancements, challenges remain in automating parameter control, ensuring effective sensor maintenance, and improving operability in rural areas, which need to be addressed. Full article

Phosphorus is the primary contributor to eutrophication in water bodies, and identifying phosphorus sources in rivers is crucial for controlling phosphorus pollution and subsequent eutrophication. Although phosphate oxygen isotopes (δ¹⁸O_P) have the capacity to trace phosphorus sources and cycling in water and sediments, they have not been used in small- to medium-sized watersheds, such as the Xiaodongjiang River (XDJ), which is located in an agricultural watershed, source–complex region of southern China. This study employed phosphate oxygen isotope techniques in combination with a land-use-based mixed end-member model and the MixSIAR Bayesian mixing model to quantitatively determine potential phosphorus sources in surface water and sediments. The δ¹⁸O_P values of the surface water ranged from 5.72‰ to 15.02‰, while those of sediment ranged from 10.41‰ to 16.80‰. In the downstream section, the δ¹⁸O_P values of the surface water and sediment were similar, suggesting that phosphate in the downstream water was primarily influenced by endogenous sediment control. The results of the land-use–source mixing model and Bayesian model framework demonstrated that controlling phosphorus inputs from fertilizers is essential for reducing phosphorus emissions in the XDJ watershed. Furthermore, ongoing rural sewage treatment, manure management, and the resource utilization of aquaculture substrates contributed to reduced phosphorus pollution. This study showed that isotope techniques, combined with multi-model approaches, effectively assessed phosphorus sources in complex watersheds, offering a theoretical basis for phosphorus pollution management to prevent eutrophication. Full article

Rice–fish culture, an ancient agronomic practice, integrates aquaculture with rice farming, a sustainable solution for enhancing food security and agricultural productivity. The recent advancements and historical perspectives on rice–fish culture have increased its ecological, economic, and social impacts. The practice spans over 2000 years and has seen significant technological improvements, especially in regions like China, Thailand, and Bangladesh. Implementations of modernized rice–fish systems demonstrate increased rice yields, reduced pest and weed prevalence, improvements in soil quality, and higher profits for farmers. For example, in China, it was reported that a rice–fishing system produced 6000–7000 kg of rice and 1500–7500 kg of fish per hectare per year. Furthermore, the fish reduce herbivore insect abundance and weed abundance, effectively eliminating the need for pesticides. Despite its advantages, challenges such as water management, the availability of quality fish seed, and socio-economic barriers remain. By synthesizing findings from various studies, we will highlight the potential of rice–fish culture to contribute to sustainable agriculture and rural development, recommending strategies for optimizing its adoption and addressing existing constraints. Full article

Aquaculture is a vital contributor to global food security, yet maintaining optimal water quality remains a persistent challenge, particularly in resource-limited rural settings. This study integrates Internet of Things (IoT) technology, Machine Learning (ML) models, and the Quantum Approximate Optimization Algorithm (QAOA) to enhance water quality monitoring and prediction in aquaculture. IoT sensors continuously measured parameters such as temperature, dissolved oxygen (DO), pH, and turbidity, while ML models—including Random Forest—provided high accuracy predictions (R² = 0.999, RMSE = 0.0998 mg/L). The integration of the QAOA reduced model training time by 50%, enabling rapid, real-time responses to changing water conditions. Over 6000 corrective interventions were conducted during the study, maintaining fish survival rates above 90% in tropical aquaculture environments. This adaptable system is designed for both urban and rural settings, using low-cost sensors and local data processing for constrained environments or cloud-based systems for real-time analysis. The results demonstrate the potential of IoT–ML–QAOA integration to mitigate environmental risks, optimize fish health, and support sustainable aquaculture practices. By addressing technological and infrastructural constraints, this study advances aquaculture management and contributes to global food security. Full article

Aquaculture in rural areas, carried out in accordance with current EU requirements, aims to contribute significantly to the conservation of the biodiversity of aquatic resources, the protection of which is a prerequisite for sustainable economic and social development. The objective of this study was to present the conceptual and technical framework and to analyze the costs and profitability of producing the consumer-attractive Eurasian perch (Perca fluviatilis L.) based on the untapped potential of hatchery infrastructure and dedicated earthen ponds for common carp (Cyprinus carpio L.) production. The experiments were conducted under Polish conditions, but the results/methods can be successfully applied in other countries, mainly in Central and Eastern Europe, where production in earthen ponds is the basis of aquaculture production. The analysis of the profitability of the venture shows that the cost structure was dominated by labor and feed inputs. Despite high variable costs, this type of production can be profitable and contribute to food security and economic development in line with the EU’s Blue Growth Strategy. The article also analyzes the potential opportunities and risks of fish production based on the Recirculating Aquaculture System (RAS) and the Recirculating Aquaculture Multitrophic Pond System (RAMPS). Full article

Despite the huge potential of aquaculture in the Amazon, several producers have abandoned the activity due to a lack of assistance, technology, and innovation. Thus, the objective of this study was to identify factors that have contributed to the withdrawal of aquaculturists from the municipality of ‘Vigia de Nazaré’, state of Pará (Northern Region of Brazil). This case study took place in 2022 through a quanti-qualitative survey, applying structured questionnaires to former aquaculturists. A total of 30 fish farms were investigated, with 11 of them being abandoned. They are distributed across 10 rural communities that have developed fish farming, with ‘Vila de Itapuá’ (18.2%) being the most representative. When active, fish farming was practiced by men (100%) aged between 51 to 60 years (54.5%) with an incomplete primary education (100%), who carried out the activity for an average of 5 years (81.8%), quitting fish farming between the years 2019 and 2020 (72.7%). All former aquaculturists owned small properties, with excavated ponds in an extensive system and used family labor. The absence of technical assistance and the high cost of feed were pointed out as the main problems in the production chain. It is worth noting that the monoculture of Tambaqui (Colossoma macropomum) accounted for 63.6% of the species produced in rural communities. In conclusion, former aquaculturists express the desire to return to fish farming due to its socio-economic importance. For this, government actions supporting technical assistance and advanced studies in fish nutrition by educational, research, and extension institutions are necessary. Full article

This study aims to investigate the nexus between small-scale freshwater aquaculture and poverty-related factors like income generation and food security in rural Madagascar. Evidence of this relationship is scarce in the Global South, particularly in island states. Using linear and logistic regressions and data collected from fish farmers and consumers across six regions in Madagascar in 2021, we obtained significant findings. Extension services, integrated production systems, and higher education are positively correlated with fish-based income generation. For instance, membership in a cooperative can double an aquaculture farmer’s total annual income compared to that of other producers. Wealth is a key determinant of food security, but female decision-makers, fish consumption, and education are also positively correlated with food security. These insights emphasize the vital roles of small-scale aquaculture and women in the household in enhancing livelihoods and food security, underscoring the need for targeted support and policy interventions to foster inclusive and resilient freshwater aquaculture in island states. Full article

The industrial transformation of hot spring villages is an important means to promote the sustainable development of the rural economy and achieve common prosperity. This study aims to explore the models of hot spring industrial transformation and reveal the influencing mechanisms in hot spring villages. Based on the theory of rural industrial transformation, an evaluation index system was constructed to measure rural industrial development by using the attribute data of enterprises in hot spring villages. Taking 19 typical hot spring villages in Fujian Province of China as examples, this study explores the process, models and influencing factors of the industrial transformation of hot spring villages from a sustainable perspective. Research results show that (1) the industrial transformation of the hot spring village includes the initial development stage and the rapid development stage, with the leading industries being transformed into service industries. (2) The industrial transformation of the hot spring village presents a gradual transformation model from hot spring aquaculture to hot spring processing and hot spring services, which not only reflects the transformation process of the hot spring village from the development of its primary industry to that of its secondary and tertiary industries, but also reveals the transformation trend of specialization and the high-end productive service industry and the convenient and high-quality transformation process of the living service industry. (3) The influencing factors of the industrial transformation of the hot spring village mainly include location conditions, the demand of the rural hot spring tourism market, government funding policy support and the choices of local villagers. This study not only enriches the theory of industrial transformation in resource-based rural areas, but also provides decision-making references for the sustainable development of hot spring villages in practice. Full article

In the EU, aquaculture ponds cover an area of 360,000 ha and are a crucial part of the rural landscape. As many ecosystem services (e.g., habitats for protected wildlife, nutrient cycling, etc.) are correlated with the proportion of reed beds relative to open-water areas, it is important in environmental studies to be able to accurately estimate the extent and the temporal dynamics of reed cover. Here, we propose a method for mapping reed cover in fish ponds from freely available Sentinel-2 imagery using the normalized difference vegetation index (NDVI), which we applied to Hungary, the third largest carp producer in the EU. The dynamics of reed cover in Hungarian fish ponds mapped using satellite imagery show a high degree of agreement with the ground-truth points, and when compared with data reported in the annual aquaculture reports for Hungary, it was found that the calculation of reed cover based on the NDVI-based approach was more consistent than the estimates provided in the report. We discuss possible applications of this remote sensing technique in estimating reed-like vegetation cover in fish ponds and the possible use of the results for climate change studies and ecosystem services assessment. Full article

The rural land use preferences of multiple agents are crucial for optimizing land-use allocation. Taking Guanlin Town, Yixing City, China as an example, this study analyzed the factors by agents effecting rural land use conversion probability, identified the objectives and the constraints within the optimization of rural land-use allocation, and simulated the optimal land-use allocation for 2030 by combining MAS with an MOPSO procedure. The results showed that the preferences and decisions of main actors effected the optimal land-use allocation. The Government determined the conversion between land-use types. The preferences of the entrepreneurs resulted in the distribution of industrial land. Town residents made a high contribution to the configuration of the town residential land by considering some factors. Rural families influenced land-use allocation by considering the quality of cultivated soils, and the optimal spatial location of aquaculture systems. Four optimization objectives were identified. The most relevant constraints were the upper and lower limits of each land-use type. The land-use types in Guanlin town in 2015 had a low intensification and an unreasonable structure. The modeling results indicated a tendency for concentrated spatial distributions of rural land. The results of the present study can provide useful support for decision-making within land planning and consequent management. Full article

Tilapia farming is the predominant aquaculture activity, with 4623 aquaculture farms in Mexico alone. It is relevant to apply technological alternatives to mitigate production costs, mainly those associated with supporting energy savings for aeration and water pumping in aquaculture farms. There is limited information confirming the feasibility of implementing photovoltaic systems connected to the grid (On grid-PV) in aquaculture farms. The working hypothesis proposed for the development of the work was that On Grid PV systems in Tilapia aquaculture farms in Mexico are technically feasible, economically viable and environmentally acceptable. Therefore, the objective of this research is to design a grid-connected photovoltaic system for rural Tilapia aquaculture farms in Mexico and analyze it with a feasibility assessment through technical, economic and environmental variables, as part of the link between academia and the productive sector. Methodologically, the On Grid-PV design was carried out in an aquaculture farm in Veracruz, Mexico, as a case study. It was developed in two stages: the field phase (1), where a non-participant observation guide and a survey with open questions were applied to perform the energy diagnosis, and the cabinet phase (2) where the calculation of the economic and environmental variables was carried out with the clean energy management software Retscreen expert, the engineering design was based on the Mexican Official Standard for electrical installations, and Sunny Design 5.22.5 was used to calculate and analyze the electrical parameters of the On Grid PV. The results revealed an investment cost of USD 30,062.61, the cost per KWp was of 1.36 USD/Watt, and the economic indicators were the net present value (USD 41,517.44), internal rate of return (38.2%) and cost–benefit ratio (5.6). Thus, the capital investment is recovered in 4.7 years thanks to the savings obtained by generating 2429 kW/h per month. As for the environment, it is estimated that 11,221 kg of CO2 equivalent would be released into the atmosphere without the On Grid-PV. In conclusion, the hypothesis is accepted and it is confirmed that On Grid-PV installations for Tilapia farms are technically feasible, economically viable and environmentally acceptable; their implementation would imply the possibility for aquaculture farms to produce Tilapia at a lower production cost and minimized environmental impact in terms of energy. It is recommended that aquaculture farmers in Mexico and the world implement this eco-technology that supports the sustainable development of aquaculture. Full article

As the number of inhabitants in Sub-Saharan Africa (SSA) increases, demand for animal-source proteins outstrips the current supply. Aquaculture is promoted to sustain livelihood and for improved food security. However, the production in SSA is still low at less than 1% of the total global production. Poor water quality is cited to be one of the factors limiting the growth of the aquaculture sector and is attributed to limited familiarity with standard aquaculture practices. Thus, a knowledge, attitudes, and practices (KAPs) survey was carried out among fish farmers in five districts of the Rwenzori region. Our results showed that 81% and 80% of them had poor knowledge and practices concerning water quality in aquaculture, respectively. Seventy percent did not know that fish farming caused pollution, while 68% believed that there was no need to treat fish farm effluents. Only 45% showed good attitudes towards water quality management. Fish farmers that fed fish with only complete pellets and those that combined them with locally available products (LAP) were 8 and 5 times more likely to possess more knowledge (p < 0.01) on water quality as compared to others that used only LAP. Slight improvements in attitudes and practices for every unit increment in knowledge were observed (p < 0.05). This limited familiarity with water quality management could severely impede the growth of aquaculture, as well as the sustainable utilization of available water resources. Therefore, there is a need for more training and improvement of extension services among fish farming communities. Full article