Pond System Research Articles (Page 1)

Beaver dam–pond systems reshape the hydrology of lowland landscapes by slowing water flow and trapping sediments, thereby reducing the movement of pollutants. This study examined how such beaver-engineered wetlands can naturally filter and signal contamination risks associated with lead (Pb). We combined data from three matrices—bottom sediments, riparian vegetation, and non-invasively collected beaver fur—across three Lithuanian sites (2022–2024). Previously published datasets on plants and sediments were complemented with new information from beaver fur to explore seasonal and age-related effects as well as differences inside and outside dam zones. Lead levels were consistently higher in sediments than in plants, while beaver fur reflected variable, site-specific exposures. These results show that beaver activity contributes to the capture and redistribution of sediment-bound Pb in wetland buffers. The approach demonstrates how beaver habitats can serve as low-cost, nature-based sentinels for pollutant monitoring. Using beaver fur as a non-invasive bioindicator and managing dam stability can improve the ecological and policy relevance of buffer zones. Overall, the findings support the integration of beaver-engineered wetlands into environmental management and EU water policy, contributing to SDG 6 goals for clean water and sustainable wetland use.

ABSTRACT Predator species of fish play crucial roles in ecosystem balance through top‐down control, a mechanism frequently exploited in biomanipulation to stock predator species. Juvenile pikeperch ( Sander lucioperca ) were stocked ( n = 52,887) in spring 2023 and 2024 and autumn 2023 to compare stocking efficiency between Recirculation Aquaculture Systems (RAS) and pond culture systems. Post‐stocking mortality was high and differed among rearing methods and stocking seasons (pond‐reared: 93.3% in spring 2023, 100% in autumn 2023, and 98.9% in spring 2024; RAS‐reared: 100% in spring 2023, 99.5% in autumn 2023, and 99.1% in spring 2024). Recapture rates of pond‐reared pikeperch stocked in spring 2023 were highest, despite being smaller than corresponding RAS‐reared pikeperch when stocked. Recapture rates of autumn‐stocked pikeperch were low for both rearing methods in the single release of 2023. Pond‐reared pikeperch were smaller when stocked (91.56 mm in spring 2023; 69.26 mm in spring 2024) but grew faster and often reached a similar size as RAS‐reared fish that were larger when stocked (139.40 mm in spring 2023; 162.80 mm in spring 2024). When recaptured in spring 2023, both groups reached a similar size (~183 mm; at recapture in spring 2024 they had nearly similar sizes pond: 169 mm, RAS: 197.25 mm). Overall, survival of pond‐reared pikeperch was significantly higher than RAS‐reared fish, even after accounting for size at stocking and season. Rearing system, rather than initial size alone, strongly influenced post‐stocking success. High density of adult European perch ( Perca fluviatilis ) preyed heavily on juvenile pikeperch, thereby limiting natural recruitment. For pond‐reared pikeperch, size was crucial due to limited energy reserves for overwintering, whereas RAS‐reared pikeperch were challenged by a delayed shift to natural prey, poor shelter‐seeking behavior, and predator naïveté. Overall, we found that stocking success depended on factors beyond size at stocking, and high mortality prevented stocking alone from achieving desired ecosystem management goals.

The carbon footprint of aquaculture in the Philippines remains underexplored, and the data on species-specific emissions across various aquaculture systems are limited. This study evaluates the carbon footprint of African catfish production in recirculating tank and pond systems through a cradle-to-gate approach. Greenhouse gas emissions were quantified for each phase of fish culture, including facility establishment, production, harvesting, packaging, and distribution. This study showed that catfish farming in a recirculating system with a stocking density of 45 kg m-3 and a cropping frequency of 2 cycles per year generated 12.04 kg CO2 eq kg LW-1 or 5.01 ton CO2 eq yr-1. In contrast, the pond system with a stocking density of 10 kg m-3 and the same cropping frequency produced an average of 2.80 kg CO2 eq kg LW-1, or 17.7 tons CO2 eq yr-1. The production phase was the largest contributor to the overall carbon footprint in both systems, with electricity comprising 75% of emissions in the recirculating tank system and fish feed accounting for 93% in the pond system. Moreover, the scenario used to evaluate the impacts of energy consumption and fingerling delivery logistics on the farm’s overall carbon footprint indicated a reduction in emissions by about 76% by switching to solar energy and utilizing locally produced fingerlings. These findings provide a viable approach to mitigating the environmental impact of African catfish farming in the Philippines.

Simple SummaryAntibiotics are commonly used in aquaculture to prevent disease, but their residues can remain in pond water and affect the environment. In this study, we measured sulfonamide and fluoroquinolone antibiotics in 40 aquaculture ponds around Wuxi, China, during two key farming stages: the summer grow-out period (August) and the autumn harvest (October). Using sensitive LC–MS/MS analysis, we found that antibiotics were widespread. Enrofloxacin, a fluoroquinolone, was dominant in August, occurring in over half the ponds at concentrations up to 2.36 µg/L. By October, sulfonamides such as sulfamethoxazole and sulfadiazine became more common, with one pond showing sulfadiazine levels above 4 µg/L. Statistical analyses confirmed a clear seasonal shift in antibiotic patterns and revealed that multiple sulfonamides were often used together in autumn. These results highlight two key issues: (1) different antibiotics dominate at different farming stages, and (2) combined use of drugs increases potential risks of antimicrobial resistance and ecological harm. To address these concerns, we recommend stricter monitoring and regulation, better farm management to reduce reliance on antibiotics, and promotion of alternative disease-control strategies. This study provides valuable baseline data for improving the sustainable and safe use of antibiotics in aquaculture.Antibiotic use in aquaculture has become widespread to sustain production and control bacterial diseases, but it poses significant ecological and human health risks due to residue accumulation and resistance development. This study investigated the occurrence, dominance, and combined use of sulfonamide and fluoroquinolone antibiotics in freshwater fish aquaculture ponds around Wuxi, China. Here, the term aquaculture refers specifically to the controlled farming of freshwater fish species such as carp and crucian carp in managed pond systems. A total of 80 water samples (collected exclusively from pond waters) were obtained from 40 ponds during the high intensity rearing and harvest stage of fish. Residues of enrofloxacin and sulfonamide antibiotics were analyzed using a validated LC–MS/MS method with detection limits in the low nanogram-per-liter range. Results revealed that antibiotics were ubiquitous in pond waters, with enrofloxacin emerging as the dominant compound in August, reaching concentrations of up to 2.36 µg/L. By October, sulfonamides, particularly sulfamethoxazole and sulfadiazine, became more prevalent, with a maximum sulfadiazine concentration exceeding 4 µg/L. Multivariate analyses demonstrated a clear seasonal shift in antibiotic profiles, while correlation analyses indicated limited combined use in summer but notable co-occurrence of sulfonamides in autumn. These findings underscore that antibiotic application patterns in aquaculture are strongly linked to production stages, with potential consequences for environmental safety, resistance development, and food security. Effective monitoring, stricter regulation, and alternative disease management strategies are urgently required to mitigate risks and promote sustainable aquaculture practices.

Disease outbreaks are a significant concern for sustainable freshwater aquaculture, especially in unmanaged pond systems. In this study, we investigated a pathogen associated with mortality in Catla catla from an unmanaged village pond in Ladwa, India. The pond entirely depended on natural productivity, with no supplemental feeding. Affected fish showed signs of illness, including reduced appetite, lethargy, and severe gill hemorrhages. Water quality analysis indicated stressful conditions, with elevated pH (9.2 ± 0.2), low dissolved oxygen (4.9 ± 0.3 mg/L), and high total ammonia (0.5 ± 0.2 mg/L). A dominant Gram-negative bacterium was isolated from gill lesions and identified as Enterobacter ludwigii (strain HAUAAHM_EL1; GenBank PP989393) using both biochemical tests and 16S rRNA sequencing. Considering the need for sustainable disease management, the antibacterial potential of an aqueous extract of Curcuma longa (turmeric) was tested in vitro. Broth microdilution assays showed concentration-dependent inhibition of the pathogen, with a minimum inhibitory concentration (MIC) of 2.5 mg/mL and a minimum bactericidal concentration (MBC) of 10 mg/mL. An MBC/MIC ratio of 4 confirmed the extract's bactericidal effect. These results confirm that E. ludwigii can act as an opportunistic pathogen in unmanaged aquaculture ponds and suggest that turmeric extract, which is easily available and eco-friendly, may serve as a potential antibacterial agent. Further research is required to evaluate the in vivo effectiveness of the extract, standardize its phytochemical composition, and examine the antimicrobial resistance profile of the isolate before recommending its practical application in aquaculture systems.

This study aims to analyze flood discharge characteristics based on hydrological data and to assess the effectiveness of implementing a polder and retention pond system for flood control. The research methods include hydrological analysis using maximum annual rainfall data (2010–2023) from the Meteorology, Climatology, and Geophysics Agency (BMKG), frequency and distribution analysis (Normal, Log Normal, Gumbel, and Log Pearson Type III), distribution suitability testing, rainfall intensity calculations using the Mononobe formula, and determining the planned discharge using the rational method. The analysis results indicate that the rainfall data conforms to a normal distribution with a mean of 469.43 mm and a standard deviation of 93.44 mm. The planned discharge for a 50-year return period is 0.70 m³/s. The planned capacity of the polder and retention pond is sufficient to accommodate this discharge, thus this system is considered effective in reducing flood risk in the study areaKeywords: Polder, Retention Pond, Flood, Hydrology, Tanjung Senai

Vibrio harveyi (V. harveyi) is a major bacterial pathogen that significantly impacts shrimp cultivation. This study aimed to evaluate the potential of bioflocs, harvested from shrimp pond systems, as a fishmeal substitute to combat V. harveyi infection in shrimp Penaeus vannamei (P. vannamei). Shrimp were fed with 6 diet formulations: Four experimental diets in which fishmeal was replaced with biofloc meal at 25, 50, 75 and 100 % (designated B25, B50, B75, and B100, respectively), a fishmeal-based control diet without biofloc (B0), and a positive control diet supplemented with β-glucan (BG). Feeding trials were conducted for 30 days, followed by a challenge with V. harveyi. Growth performance, survival rates, total hemocyte count (THC), phagocytic activity, and histopathological changes were evaluated. The results demonstrated that all biofloc-fed groups had growth performance comparable to the B0 and BG groups. Shrimp fed with the B25, B50, and B75 diets exhibited significantly enhanced immune responses, with elevated THC and phagocytic activity. In the V. harveyi challenge, the B25 group showed the highest survival rate among biofloc diets, comparable to that of the BG group. Histological analysis revealed that B25 and B50 diets reduced hepatopancreatic and muscle damage associated with infection. In conclusion, this study provides evidence that substituting fishmeal with biofloc (25 - 50 %) effectively enhances immune function and confers protection against V. harveyi infection in P. vannamei, supporting its potential as a sustainable functional feed ingredient in shrimp aquaculture. HIGHLIGHTS Biofloc meal partially replaced fishmeal in shrimp feed at 25-50 % substitution levels. Growth performance and feed conversion ratios were comparable to commercial feeds. Total hemocyte count and phagocytic activity were significantly improved. Biofloc diets enhanced the survival of Penaeus vannamei challenged with Vibrio harveyi. The 25 -50 % biofloc diet offered protection comparable to β-glucan-supplemented feed GRAPHICAL ABSTRACT

Comprehensive attenuation mechanism of antibiotics in stabilization pond system receiving treated wastewater effluent: evidence from batch reactor experiments

Multi-objective spatial optimization of pond system for diffuse pollution control of paddy field watershed in the middle reaches of the Yangtze River

Gracilaria verrucosa, a red alga that is used in the manufacturing of agar, has a significant impact on coastal ecosystems and is important in several industrial uses. This study examines the effects of different densities (10, 20, and 30 individuals) of green mussels (Perna viridis) on the growth, agar yield, viscosity, gel strength, and ability to remove lead from water in brackish water pond systems. The research used a randomized complete block design with three replications. The findings indicate that the density of green mussels does not have a substantial impact on agar production, gel strength, or the effectiveness of lead removal. The density of green mussels affects the daily growth rate (DSGR) and viscosity. Lower densities (10 mussels) show better early performance, but these differences diminish over time. The presence of consistent salt levels indicates that salinity has less impact on production outcomes. This study elucidates the dynamics between algae and mussels in aquaculture systems, providing recommendations for enhancing production practices and implementing bioremediation strategies.

Microalgae are a promising feedstock for biodiesel due to their rapid growth, high lipid content and ability to use non-arable land and wastewater. This review synthesises recent advances in artificial intelligence (AI)-driven strain optimisation, engineering, nanotechnology-assisted processing, and life cycle and technoeconomic insights to evaluate pathways for industrialisation. Over the past decade (2015-2024), genetic engineering and, more recently, AI-guided strain selection have improved lipid productivity by up to 40%. Cultivation advances, including hybrid photobioreactor-open pond systems and precision pH/CO2 control, have enhanced biomass yields while reducing costs. Innovation in lipid extraction, such as supercritical CO2 and microwave-assisted methods, now achieves >90% yields with lower toxicity, while magnetic nanoparticle-assisted harvesting and electroflocculation have reduced energy inputs by 20-30%. Life cycle analyses (net energy ratio ~2.5) and integration of high-value co-products (e.g. pigments and proteins) underscore the need to align biological innovations with techno-economic feasibility. This review uniquely integrates advances in AI, CRISPR and nanotechnology with life cycle and techno-economic perspectives, providing a comprehensive framework that links laboratory-scale innovation to industrial feasibility and positions microalgal biodiesel as a viable contributor to global decarbonisation strategies.

Abalone is among the most highly prized seafoods, valued for its delicate flavor and texture. As abalone aquaculture continues to expand, addressing its environmental impacts has become increasingly important. Although aquaculture is recognized as a contributor to greenhouse gas (GHG) emissions, the specific mechanisms and pathways of GHG emissions—particularly in abalone farming—remain poorly understood. To clarify the patterns and drivers of GHG emissions in abalone (Haliotis discus) culture systems, this study was conducted in three aquaculture ponds located in Gongliao District, New Taipei City, Taiwan. We measured CO2, CH4, and N2O fluxes along with key environmental parameters to assess variation across sampling locations, times, and seasons. The results showed that sampling time had no significant effect on GHG flux variations, whereas seasonal changes influenced all three gases, and sampling location significantly affected N2O flux only. During the culture period, average fluxes were 2.19 ± 10.83 mmol m−2 day−1 for CO2, 2.11 ± 2.81 µmol m−2 day−1 for CH4, and 1.65 ± 2.73 µmol m−2 day−1 for N2O, indicating that the abalone ponds served as net sources of these GHGs. When converted to CO2-equivalents (CO2-eq), the total average CO2-eq flux from the ponds was 0.02 ± 0.09 mg CO2-eq m−2 day−1, calculated using global warming potential (GWP20 and GWP100) metrics. This study provides the first comprehensive assessment of GHG emissions in abalone pond systems and offers valuable insights into their emission dynamics. The findings contribute to the scientific basis needed to improve aquaculture GHG inventories.

Abstract Coastal pond fisheries are widely used by the community to raise fish or shrimp. Changes in environmental conditions greatly affect the fish raised in ponds. Unstable water quality can cause stress to pond biota, reduce productivity, and even cause mass fish deaths, resulting in economic losses for pond farmers. A monitoring system is needed that can provide real-time information and inform farmers about dangerous changes in water quality. As a solution to this problem, an Internet of Things (IoT)-based pond water quality detection system has been developed that can monitor water quality parameters in real-time. This system uses an Arduino Uno R3 microcontroller with ESP8266 as a control center, which is connected to pH, temperature, and TDS sensors to detect water conditions directly. The measured data is displayed on the LCD screen and sent to a mobile application via a WiFi connection, so that farmers can monitor pond conditions remotely. Test results showed that the system was highly accurate: pH accurate with an accuracy of 1.22 percent, temperature was accurate with an accuracy of 1.73 percent, and TDS was accurate with an accuracy of 3.10 percent. The system’s portable design, which uses a rechargeable lithium-ion battery, also means it does not rely on a constant power supply to maintain optimal operating conditions. In addition, the system is designed to operate in a pond environment, ensuring reliability under a wide range of operating conditions. IoT-based monitoring systems enable farmers to manage their ponds remotely, saving time and effort.

Integrated field-scale natural composite oxidation pond system for livestock wastewater treatment: Microbial insights and nutrient removal dynamics.

ABSTRACT Pond systems represent the simplest and most widely used technology for treating high-strength wastewater containing biodegradable suspended solids. When covered, they offer advantages such as odour control, intensified organics degradation, and biomethane capture. However, their efficiency is often limited by unmixed zones and the formation of floating or sinking layers, which reduce residence times and treatment performance. Here, we developed a novel mixing concept for anaerobic pond systems and systematically tested its mixing efficiency. The novel mixing concept avoids permanently installed mechanical components and instead relies on a planar, kite-like mixing tool that is moved horizontally through the pond by an external rope-guided system. This design enables flexible, low-maintenance operation with minimal energy input and is particularly suitable for shallow, large-scale ponds where conventional submerged mixers are impractical. Three different mixing tool designs were evaluated using dye and conductivity tracer experiments with model substates in a 330 L pilot-scale pond. All tools were based on perforated planar plates with identical open area ratio (44 %), but differed in hole geometry. The effect of substrate viscosity was assessed at two distinct velocities. Results showed that increasing viscosity significantly prolonged the mixing time, while doubling the mixing velocity reduced it by a factor of four. The mixing tool design strongly impacted flow patterns and therewith the mixing efficiency. Findings were integrated into an operation scheme for full-scale anaerobic pond systems equipped with planar mixing tools that accounts both for the mixing performance and the economic efficiency.

The lotus-fish co-culture (LFC) system leverages plant-fish symbiosis to optimize aqua-culture environments, enhancing both economic and ecological yields. However, the eco-logical mechanisms of microbial communities in LFC systems remain poorly understood, particularly regarding the functional roles of fungi, archaea, and viruses. This study compared microbiota (viruses, archaea, fungi) in water, sediment, and fish (crucian carp) gut of LFC and intensive pond culture (IPC) systems using integrated metagenomic and environmental analyses. Results demonstrated that LFC significantly reduced concentrations of total nitrogen, total phosphorus, and nitrite nitrogen and chemical oxygen demand in water, and organic matter and total nitrogen in sediment compared to IPC. Community diversity analysis, LefSe, and KEGG annotation revealed suppressed viral diversity in LFC, yet increased complexity and stability of intestinal virus communities compared to IPC. Archaeal and functional analyses revealed significantly enhanced ammonia oxidation and OM decomposition in LFC versus IPC, promoting methane metabolism equilibrium and sediment organic matter decomposition. Moreover, crucian carp intestines in LFC harbored abundant Methanobacteria, which contributed to maintaining a low hydrogen partial pressure, suppressing facultative anaerobes and reducing intestinal infection risk. The abundance of fungi in sediment and crucian carp intestine in LFC was significantly higher than that in IPC, showing higher ecological self-purification ability and sustainability potential in LFC. Collectively, LFC's optimized archaeal-fungal networks strengthened host immunity and environmental resilience, while viral community suppression reduced pathogen risks. These findings elucidate microbiome-driven mechanisms underlying LFC's ecological advantages, providing a framework for designing sustainable aquaculture systems through microbial community modulation.

Spatio-temporal distribution of environmental DNA from amphibian and turtle species in a pond ecosystem.

Digital PCR-based assessment of pathogens in wastewater and antibiotic resistance genes in drinking water of the Kathmandu Valley, Nepal.

The Upaya Mina Group in Banyuasih, Sumedang, cultivates common carp using a running water pond system but faces challenges due to rising feed costs that are not matched by the selling price of fish. This community service activity aims to provide a solution through the implementation of a polyculture system combining common carp and Nile tilapia to improve feed efficiency. The method used involved educational outreach through demonstrations and pilot trials at the group’s aquaculture site. The trial results showed that the polyculture system produced 810 kg of fish with a feed efficiency of 76%. In comparison, the group’s previous monoculture system yielded only 640 kg with a feed efficiency of 59%, despite using the same amount of feed, which was 1 ton. The implementation of the polyculture system increased production by 170 kg and feed efficiency by 17%. Thus, the polyculture system not only boosts production but also offers a practical solution to the problem of high feed costs.

The in-pond raceway system (IPRS) is a modern aquaculture innovation that enables high-density fish culture while maintaining optimal water quality. It presents a promising solution for enhancing fish production efficiency in land- and resource-constrained regions like Bangladesh. This study aimed to evaluate and compare the economic performance of culturing multiple freshwater fish species in IPRS cell and pond systems over a 120-day period, from October 1, 2022, to January 31, 2023, in Sharsha, Jashore, Bangladesh. A total of 2,46,862 individuals of Labeo rohita, Ctenopharyngodon idella, Channa striata, and Clarias batrachus were stocked in an IPRS cell (0.132 ha) and fed a commercial feed three times daily. Simultaneously, 16,000 individuals of L. rohita, Catla catla, Hypophthalmichthys molitrix, and Oreochromis mossambicus were stocked in the adjacent IPRS pond (2.26 ha), which received no feed but relied on natural plankton and waste feed from the cell. Water temperature, dissolved oxygen, pH, and transparency were monitored every 15 days throughout the study. At the end of the culture cycle, fish production reached 68,621 kg in the IPRS cell and 22,332 kg in the IPRS pond. The total costs and net benefits were BDT 50,53,517 and BDT 99,78,388 for the cell, and BDT 4,75,163 and BDT 29,60,265 for the pond, respectively. The cost-benefit ratio (CBR) was 1.97 for the IPRS cell and 6.23 for the IPRS pond. When combined, the IPRS cell with pond system yielded a net benefit of BDT 1,29,38,653 with a CBR of 2.34. The study concludes that integrated culture in IPRS cell and pond maximizes both resource efficiency and economic return. These findings highlight the potential of climate-smart IPRS technology, especially the integrated model, as a scalable and profitable aquaculture solution for developing regions. It offers a sustainable strategy for increasing fish production, reducing input costs, and improving rural livelihoods through employment generation and food security.