Spatio-Temporal Patterns of Nitrogen and Phosphorus Stoichiometry in Cascade Ponds in an Agricultural Small Watershed and Their Influencing Factors

Ecological stoichiometry of nitrogen and phosphorus is an important indicator to characterize the nitrogen and phosphorus trophic status in aquatic ecosystems. The study of the spatio-temporal patterns of nitrogen and phosphorus stoichiometry is beneficial to the nitrogen and phosphorus pollution management in pond ecosystems. In this study, 18 groups (36 in total) of typical cascade ponds were selected as long-term observations to investigate the spatial distribution patterns of nitrogen and phosphorus component ratios (ratio of total nitrogen to phosphorus: TN:TP, ratio of dissolved nitrogen to phosphorus: TDN:TDP, ratio of particulate nitrogen to phosphorus: PN:PP) in water bodies in the tropical agricultural watershed of Jinjing. The results showed that the average values of TN:TP and TDN:TDP in the upstream ponds were 26.4 and 53.4, respectively, and were more than those in the downstream (22.95 and 48.1, respectively). In contrast, the PN:PP (13.78) in the upstream was significantly lower than that of the downstream (30.39). Furthermore, the factors of rainfall, agricultural land use and fish farming influenced the spatio-temporal variability of the N:P ratios. The ratios of TN:TP and TDN:TDP were higher in the wet season and lower in the dry season. Agricultural land use and fish farming reduced the ratios of the above three nitrogen and phosphorus components in cascade ponds in the study area. Our results show that strengthening agricultural land pollution control and aquaculture management could help to improve water quality of pond ecosystems in the study area.

The Influence of Land Use and Fish Farming on the Contents of Ca²⁺, Mg²⁺, K⁺and Na⁺in Pond and Reservoir Ecosystems in an Agricultural Small Watershed, China

It is not understood well that how the effects of land use and fish farming on the contents of alkali metals (Ca2+, Mg2+, K+ and Na+) in small water bodies of pond and reservoir ecosystems at the watershed scale. In this study, the concentrations of Ca2+, Mg2+, K+ and Na+ in water bodies were measured for 103 ponds and reservoirs used as fish farming or surrounded by different agricultural land use types in the subtropical hilly watershed of Jinjing (105 km2), China. The two important environmental factors of fishing farming and agricultural land use influenced the spatial variation the contents of alkali metals. The ponds and reservoirs in residential area had significantly higher concentrations of Ca2+ and Na+ than those with other land use types, reflecting the influence of domestic wastewater. Compared with those of natural ponds with non-fish farming, no significant increase of alkali metal contents occurred in fish farming ponds, due to the regular cleaning of ponds by farmers. However, the effect of fish culture on alkali metal contents was still supported indirectly by the fact that the alkali metal contents significantly correlated with nitrate contents in fish farming ponds and but high related with that of DIP in natural ponds. The suitability assessment for irrigation on the pond water indicated that almost all of ponds were suitable for irrigation except some ponds surrounded by residential area and tea plantation. Generally, our results demonstrated that fish farming and agricultural land use affected the contents of alkali metals in ponds and reservoirs. The agricultural water irrigation would be with caution from the ponds with tea plantation and residential area in the subtropical hilly watershed.

Eco-drainage Pond in Non Irrigated Land for the Conservation of Land and Water Based on Community Participation

There are some bad impacts from a critical land such as flood in rainy season and dryness in dry season. Long dryness could cause shortage of water for human consumption, industry and agriculture. Prevention has been made to avoid the both bad impacts by building hydraulic structures like reservoirs and ponds in order to reduce the peak flow during the rainy season and to store the water for use during the dry season. However, they gradually become full of sediment. This will make them work insufficiently and will cause high maintenance cost. Moreover, wells in agriculture field used as retention also suffer dryness to make crop failure. This study aims to develop a model of pond for conservation of land and water in non irrigated land. Community participation is crucial in order to solve the flood and dryness problems. The community, especially the farmers will participate actively in the implementation and maintenance of the model. There are benefits in using the pond model such as： （1） to control sediment transport to the rivers, reservoir or other hydraulic structures; （2） to reduce flood rate; （3） to increase ground water recharge; （4） to contain water for agriculture and （5） to control the fertility of land. The cost of making a unit of model （sedrainpond） of 1.5 m diameter and 1.5 meter depth is relatively cheap between $10 to $20 （US）, and the maintenance is done by the farmers. When the pond model becomes functional, besides containing water in the rainy season, the water can be used to sustain water for agriculture in the dry season to avoid any crop failure. When the pond becomes dry, the farmers can harvest the suspended load sediment such as clay or silt to spread onto their land to keep its fertility.

The Relationship between the Area of Aquaculture Pond and Purification Pond in Water Circulation Aquaculture System

The establishment of water circulation aquaculture system realized the hi- erarchical use of nitrogen, phosphorus and other eutrophic substances in aquaculture wastewater and the recirculation use of water resource. However, no research has been reported on the detailed calculation of the relationship between the area of aquaculture pond and purification pond. In this study, referring to the absorption ability of aquatic plants to pollutants in aquaculture wastewater and pollutant generation and discharge coefficient in aquaculture pond, based on the general rules of water quality management in freshwater aquaculture system, a calculation mode was es- tablished to investigate the relationship between the area of aquaculture pond and purification pond in freshwater recirculation aquaculture system, which was feasible to explain related cases and would provide theoretical basis to reduce the economic costs in the construction of water circulation aquaculture system and realize the bal- ance between the ecological benefits and the economic benefits.

Perceptions of the Role Played by Aquaculture and the Services It Provides for Territories: Complementarity of Survey Types

This article discusses the perception of ecosystem services for French and Brazilian pond fish farming. Its aim is to study the extent to which the industry and its stakeholders are aware of the existence of such services in order to be able to prioritize them with respect to social well-being. This identification phase is seldom discussed. It requires that survey questionnaires be designed so as to improve understanding of these perceptions. The surveys undertaken combined both open questions where the interviewees expressed their perceptions spontaneously and closed questions where they were invited to rank a pre-established list of the relevant services. These surveys involved 133 fish farmers and 93 stakeholders. The results show that perceptions differ by question type, and confirm the significance of the questionnaire design and the importance of combining several kinds of approach.

Approximate Compositional Values and Tissue Fatty Acid Profiles of Nile Tilapia (<i>Oreochromis niloticus</i>L.) Fed <i>Azolla</i>-Diets in Earthen Ponds

The approximate general composition and the fatty acid profile of Nile tilapia fed Azolla-diets in ponds were studied for 90 days. Six isonitrogenous (29.2% CP) and isoenergetic (16.9 kJ·g>sup>-1) diets were formulated to contain 0% (A0), 10% (A10), 20% (A>sub>20), 30% (A30), 40% (A40) and 50% (A50) of Azolla meal (AM), as partial fish meal (FM) substitutes. Diet A0 without AM served as a control. Fish growth decreased as AM level exceeded 20% in diets (P 0.05). Crude lipid was significantly lower in fish fed A50 and significant differences were also found in crude ash (P 20, A30 and A50. High level of the fern reduces growth without negatively affecting fatty acid in fish. Fish PUFA, especially the (n - 3) fatty acids, are affected positively, even when fed 50% AM, which is good for the quality of the fish produced in regard to the benefits for the health of consumers.

Influence of Management on the Water Quality and Sediment in Tropical Fish Farm

A seven-month research evaluated the management effect on the water quality and sediment of seven fish ponds. Water and sediment were collected at nine sample sites: seven in the fish ponds;one in inlet water and another in the fish farm’s effluent. The soil samples were analyzed for macro- and micro-nutrients and the water samples were analyzed for physical and chemical parameters. Management and local climate conditions affected nutrient seasonality in the sediment and featured high concentrations of Al, Ca, Cu, K, Mg, C, Na, Zn and OM at the effluent with low pH, ranging between 4.4 and 6.5. Sudden decrease of DO (less than 3 mg/L) during the rainy season, with a 180 mmrainfall, and a TSS increase (approximately 10 mg/L) were reported. Use of organic manure in fish pond V6 caused higher rates of ammonia (over 1 mg/L). Due to the sediment’s acid pH (less than 4.8) and Al at 0.92 mg/L at the effluent, great care was required in the fish farm. Maintenance and procedures management in the fish farm under analysis should be given more attention since high levels of Al, Fe and acid pH and low levels of potassium and phosphorus in the sediment may produce unfavorable conditions in the water column, and may ultimately have an impact on fish.

The Development of a Renewable-Energy-Driven Reverse Osmosis System for Water Desalination and Aquaculture Production

Water and energy are closely linked natural resources - the transportation, treatment, and distribution of water depends on low-cost energy; while power generation requires large volumes of water. Seawater desalination is a mature technology for increasing freshwater supply, but it is essentially a trade of energy for freshwater and is not a viable solution for regions where both water and energy are in short supply. This paper discusses the development and application of a renewable-energy-driven reverse osmosis （RO） system for water desalination and the treatment and reuse of aquaculture wastewater. The system consists of （1） a wind-driven pumping subsystem, （2） a pressure-driven RO membrane desalination subsystem, and （3） a solar-driven feedback control module. The results of the pilot experiments indicated that the system, operated under wind speeds of 3 m s-~ or higher, can be used for brackish water desalination by reducing the salinity of feedwater with total dissolved solids （TDS） of over 3 000 mg L-1 to product water or permeate with a TDS of 200 mg L-~ or less. Results of the pilot experiments also indicated that the system can remove up to 97% of the nitrogenous wastes from the fish pond effluent and can recover and reuse up to 56% of the freshwater supply for fish pond operation.

Effects of Rice-Fish Co-culture on Oxygen Consumption in Intensive Aquaculture Pond

Rice-fish co-culture has gained increasing attention to remediate the negative environmental impacts induced by intensive aquaculture. However, the effect of rice-fish co-culture on oxygen depletion has rarely been investigated. We constructed a rice-fish co-culture system in yellow catfish(Pelteobagrus fulvidraco) and freshwater shrimp(Macrobrachium nipponense) ponds using a new high-stalk rice variety, and conducted a field experiment to investigate the effect of rice-fish co-culture on water parameters and oxygen consumption. The results showed that rice-fish co-culture reduced the nutrients(total nitrogen, ammonia-N, total phosphorous and potassium) and the dissolved oxygen content in fish and shrimp ponds. However, they showed similar seasonal change of dissolved oxygen in the water of fish and shrimp ponds. Rice-fish co-culture reduced the total amount of oxygen consumption and optimized the oxygen consumption structure in pond. The respiration rates in water and sediment were significantly reduced by 66.1% and 31.7% in the catfish pond, and 64.4% and 38.7% in the shrimp pond, respectively, by additional rice cultivation. Rice-fish co-culture decreased the proportions of respiration in sediment and water, and increased the proportion of fish respiration. These results suggest that rice-fish co-culture is an efficient way to reduce hypoxia in intensive culture pond.

Model of Wetland Carbon Sequestration in the Venetian Lagoon, Italy

This research deals with an evaluation of the sink of greenhouse gas CO2 in a eutrophic area of the Venetian lagoon where fish is farmed （＂Valle da pesca＂）. Following CDM UNFCCC （Clean Development Mechanism United Nations Framework Convention on Climate Change） criteria, this can be considered relevant to the international standard for the voluntary evaluation of carbon credits on the basis of Annex a of Kyoto Protocol. To identify the ＂Valle da pesca＂ brackish lagoon properties regulating the carbon dioxide （CO2）, a survey has been performed during three seasons in one year and in four different locations. These places are located in the Italian Venetian Lagoon and in the Grado Lagoon in North Italy, Europe. To identify the CO2 sink capacity, a special index is calculated. The CO2 concentrations and sink are regulated by the balance of autotrophic and heterotrophic activities, and the sediment anoxic denitrification and macro algae are crucial tank of CO2 in the valley shallow waters. The ponds potential-CO2 yield of 80-124 kg/m2 per year and the value are related and proportional to the correct human environmental control （water flux control）.

Mathematical Equations for Reducing Water Pollution Problems among Poultry Production Clusters in Nong Khai Province, Thailand

Poultry production clusters (PPC) in Nong Khai raise layer chickens in the poultry houses constructed over fish ponds. Layer farmers use chicken manure to feed their fish. However, unbalance between chicken raising and the size of fish pond or number of fish results in low water quality, which affects fish production and the community’s public water resource. In this field study, data was collected from layer farms in three poultry production clusters in Nong Khai province in the northeast of Thailand (a total of 90 farms) between April and August 2013. Data collected consisted of observations of dissolved oxygen (DO) values of water in the fish ponds, the number of egg-laying chickens raised above the fish ponds, the number of fish and size of the fish ponds. When all of these four observations were analyzed, mathematical equations for calculating the number of chickens raised, the number of fish per one rai (1600 m2), and the size of pond suitable for the number of chickens and fish were obtained as follows: 1) number of fish/rai = 5796 + 1097(size of pond) (R2 = 0.71), 2) number of chicken/rai = 513 + 223(size of pond) (R2 = 0.48) and 3) size of pond =-0.328474 + 0.000262(Fish) + 0.00117(Chicken) (R2 = 0.40). When pond = desired pond size, fish = number of fish to be raised and chicken = number of chickens to be raised.

Metal Concentration in Muscle Tissue of Carp and Pike from Different Fish Ponds in Belgrade Area

This study was conducted to determine the contamination data of some heavy metals in 10 fish tissue samples of two different fish species---common carp and Northern pike from four different fish ponds and to compare the level of contamination and the differences in the concentration of these elements between these two fish species and between compared fish ponds. In various fish ponds, metal concentrations in the carp muscle tissue varied depending on the metal type. Between compared fish ponds, there were significant differences （P 〈 0.01） in the concentration in muscle carp tissue, except for cadmium. Metal concentrations in the pike muscle tissue also varied among fish ponds, depending on the type of metal. In all compared cases, there were significant differences between metal concentration in pike muscle tissue （P 〈 0.01）. Lead and cadmium concentration in pike muscle tissue were significantly higher （P 〈 0.01, P 〈 0.05, respectively）, and mercury and arsenic concentration were significantly lower （P 〈 0.01） than concentration of this heavy metals in carp muscle tissue in all comapered fish ponds. The results obtained in this study indicate variation in a range of examined metal concentration in muscle tissue, which seems to be typical for the Serbian fish ponds, but is lower than those in rivers with considerable anthropogenic impact.

Treatise by Olbrycht Strumieński (1573)--The First Polish Book on Hydraulic Engineering

The treatise by Olbrycht Strumieński is chronologically the first book in Poland, and the second in Europe, describinglevelling instruments. A few years after Strumieński’s death, the text was published by Stanisław Stroynowski. Until the 19th century,only three Polish-language treatises addressed the problems of levelling. Strumieński described the technique of building andmanaging fish ponds in Moravia, Bohemia and Poland. The presented surveying instruments and measuring methods are sufficientfor the design and construction of a pond that can survive for over 300 years. Strumieński also presented the principles of freshwateraquaculture. Poland, along with Bohemia, Moravia and Hungary, was an exporter of freshwater fish to Western Europe from the 16thto the mid-18th century.

A Degassing Inlet Structure for Aquaculture Ponds

Structures separating fish hatchery ponds from open spring water sources must restrict fish movement from the pond to the spring, allow for constant water flow, and potentially reduce incoming spring water gas supersaturation. This article describes a novel inlet structure that fulfills those requirements. In addition, it requires minimal maintenance, and allows for the quick and easy removal of debris in the event of partial plugging. This simple aluminum structure consists of a mount for attachment to the inflow pipe and a terminal splash plate with aeration holes. The splash plate is perpendicular to the water flow during normal operations to both prevent fish from jumping into the pipe and aerate the incoming water. However, it can be easily swiveled upward for the efficient removal of debris. Use of the inlet structure consistently decreased gas supersaturation in the spring water as it entered the fish production pond. By decreasing gas levels and maintaining water flows, potentially hazardous fish health issues can be avoided by using this structure. In addition, this relatively inexpensive and simple device will greatly reduce the labor required for removing debris compared to traditional screens.

Microbial Assessment and Antibiotic Susceptibility Profile of Bacterial Fish Isolates in an Aquaculture Production Site in Mefou Afamba Division of Cameroon

The practice of integrated fish farming and the use of local fish meal and manure for fish feeding in Cameroon constitute potential sources of resistant pathogenic bacteria in the fish pond environment.Therefore,a periodical and constant monitoring of the microbiological quality of fish pond is imperative.This study was to assess the microbial contamination of Mfou aquaculture production site and evaluate the antibiotic resistance profile of bacterial fish isolates.Samples of pond water(n=36),sediment(n=36),fishmeal(n=12)and African catfish(Clarias gariepinus),kanga(Heterotis niloticus)and Nile Tilapia(Oreochromis niloticus)(n=36,each)were collected to determine TVAC(Total Viable Aerobic Bacterial Count),FC(Fungal Count),SAC(Staphylococcus aureus count),TCC(Total Coliform Count)and FCC(Feacal Coliform Count).The fish skin isolates of S.aureus,Enterobacter sakazakii,Citrobacter freundii,Serratia fonticola,Klebsiella oxytoca,Proteus spp.,Aeromonas hydrophila,Kluyvera spp.,Moraxella spp.,Pasteurella multocida and Pseudomonas fluorescens were tested against penicillin G(10μg),chloramphenicol(30μg),sulfamethoxazole/trimethoprim(25μg),erythromycin(15μg),tetracycline(30μg),using the disk diffusion method.Results reveal a heavy contamination of fish farms with microbial load above the recommended limits.Our study indicates that fish ponds are sources of zoonotic pathogens underlining their epidemiological and clinical relevance.All bacterial isolates were multiresistant with a multiple antibiotic resistance index above 0.2.These data raise concern about the microbial contamination of aquaculture and associated public health risks in Cameroon.

Determination of five endosulfan pesticides in the fish pond water by dispersive liquid–liquid microextraction combined with GC–MS

A simple and rapid dispersive liquid-liquid microextraction(DLLME)technique coupled with gas chromatography-ion trap mass spectrometry(GC-MS)was developed for the extraction and analysis of five endosulfan pesticides from the fish pond water.In this work,different parameters affecting the extraction process such as the type and volume of extraction solvent,type and volume of disperser solvent,and extraction time were studied and optimized.Under optimized conditions,the enrichment factor ranged from 189 to 269 and the relative recovery ranged from 88.5%to 94.9%.The linear range was 2.0-80.0 mg/L;the limits of detection and quantitation were in the range 0.04-1.06 mg/L and 0.12-3.53 mg/L,respectively.The relative standard deviations were in the range 0.94%-2.08%(n D 5).The obtained results show that DLLME combined with GC-MS is a fast and simple method for the determination of endosulfan pesticides in fish pond water.

基于改进YOLOv8n的渔光互补池塘作业船导航中线提取方法

在复杂渔光互补池塘环境中,传统机器视觉算法易受光影变化、池中水草分布和水面障碍物遮挡等因素干扰,导致视觉导航线检测效果不佳。针对上述问题,该研究提出了一种基于改进YOLOv8n的渔光互补池塘作业船导航中线提取方法。首先从提高检测实时性角度出发,将HGNetV2网络作为主干网络,采用组归一化方式(group normalization,GN)与共享卷积结构,设计轻量化检测头网络,减小模型体积;然后使用SPPF_LSKA模块作为特征融合层,提高模型多尺度特征融合能力;最后采用Wise-IoU(weighted interpolation of sequential evidence for intersection over union)损失函数,提升边界框回归性能和对中远处小目标的检测精度。利用改进YOLOv8n检测框坐标提取两侧水泥立柱定位参照点,通过最小二乘法拟合两侧水泥立柱行线,进而使用角平分线提取导航中线。消融试验结果表明,相对于原始YOLOv8n模型,改进YOLOv8n模型的计算量、参数量和模型体积分别下降36.0%、36.8%和32.8%,平均精度均值(mean average precision,mAP)为97.9%,查准率为93.1%,单张图像检测时间为6.8 ms,检测速度提升42.9%。不同模型对比试验表明,改进YOLOv8n模型在较低计算成本的基础上,体现出了良好的实时性与精准度检测性能,具有明显优势。在导航中线定位分析试验中,提取水泥立柱定位参照点与人工观测标记点平均直线误差在0~5和5~10 m距离范围内分别为3.69 cm和4.57 cm,提取导航中线与实际导航中线平均直线误差为3.26 cm,准确率为92%。在导航中线实时性试验中,导航中线平均提取速度为22.34帧/s,满足渔光互补池塘无人作业船导航要求,为后续作业船视觉导航系统研究提供参考。

长江流域2种水产养殖模式的生命周期环境影响评价

本研究以长江流域内的池塘养殖和稻渔综合种养2种水产养殖模式为对象,应用生命周期评价方法,分析2种养殖模式对能源消耗(EU)、全球变暖潜势(GWP)、酸化潜势(AP)、富营养化潜势(EP)以及水资源消耗(WU)5种环境指标的影响,并探究2种主要输入因子(饲料和电力供应)和养殖过程对各环境指标的影响,从而评价2种养殖模式对环境影响的差异。生命周期评价结果标准化处理和加权评估显示,稻渔综合种养模式的WU、EP、GWP、AP和EU值分别为11.650、0.770、0.141、0.096和0.003,总环境影响指数(TEII)为12.660;池塘养殖模式的WU、EP、GWP、AP和EU值分别为31.453、1.187、0.210、0.174和0.007,TEII为33.031。与稻渔综合种养模式相比,池塘养殖模式的各项环境指标均较高。对环境影响的贡献率分析表明,饲料供应对EU、GWP和AP的贡献率最高,EP主要受饲料供应和养殖过程的共同影响,而WU主要集中在养殖过程中,电力供应主要影响EU、GWP和AP。生命周期评价的结果表明,与池塘养殖模式相比,稻渔综合种养模式显示出更友好的环境效益,在我国长江流域具有较大的发展空间。2种养殖模式的贡献率分析表明,改进饲料生产工艺、建立精准投喂技术、应用先进的尾水处理技术和适当提高养殖密度是我国长江流域水产养殖环境友好生产的关键。

基于物联网的智能鱼塘水质环境监测系统设计

文章设计并实现了一种基于STM32的智能鱼塘水质环境监测系统。该系统旨在通过实时监测鱼塘水质参数,如温度、溶解氧、pH值、氨氮和亚硝酸盐,提供科学的养殖环境管理支持。系统硬件包括STM32微控制器、各类传感器、LCD显示屏和PC端软件,软件架构则涵盖数据采集、处理、传输及用户界面模块,最后的实验结果验证了系统的有效性。