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.

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.

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.

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.

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.

Nitrogen and Phosphorus Removal from Lake Kinneret Inputs

The Hula Valley was drained in 1957. The land use was modified from natural wetland and old shallow lake ecosystems to agricultural development. About half of the drained land area was utilized for aquaculture. Population size was enhanced and the diary was developed intensively resulting in the enhancement of domestic and husbandry sewage production that increased as well. The natural intact Hula Valley-Lake Kinneret ecosystem was heavily anthropogenically interrupted: The Hula was drained and Kinneret became a national source for domestic water supply. Some aspects of the environmental and water quality protection policy of the system are presented. The causation and operational management implications for the reduction of Nitrogen and Phosphorus migration from the Hula Valley are discussed. Drastic (81%) restriction of aquaculture accompanied by sewage totally removed achieved a reasonable improvement in pollution control which was also supported by the Hula Project. The implications of anthropogenic intervention in the process of environmental management design are presented.

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。

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。

气象条件对夏季鱼塘溶氧垂直变化影响及对策研究

鱼塘溶氧垂直差异大小是健康生态养殖的重要指标之一。基于湖北洪湖2022年6月21日—7月14日鱼塘溶氧、水温、光强等上下垂直分层观测资料,以及同步地面气象观测资料,分析了鱼塘水体溶氧日变化特征,在排除了人为因素干扰相关资料后,采用统计回归方法,诊断分析了上下层溶氧差异与气象环境因子关系。结果表明:夏季晴好天气下,随进入水体的光照增强,上层溶氧常处于饱和或过饱和,下层处于低溶氧状态;120 cm层溶氧增量与光强呈不显著的负相关,鱼塘下层难以通过光合产氧满足底层鱼类溶氧需求。鱼塘水体温度上高下低的垂直梯度会阻碍氧向下迁移,在30 cm与60 cm两层水温相差1℃的情况下,其溶氧量差可达6.6 mg/L。在风的作用下,风力越大,上下层水温差异越小,迁移阻力小、迁移快,溶氧差异小;地面极大风速达9 m/s以上时,鱼塘上下层的溶氧差异小,无需人工干预增氧。打破水温垂直梯度变化是确保夏季鱼塘良好生态环境重要手段,人为干预强度由风力的大小决定,风力越小,所需干预力度越大。研究结果以期为鱼塘健康养殖,降低生产成本、减少灾害损失,以及促进水产养殖智能机械化发展提供科学依据。

晋祠鱼沼飞梁结构整体稳定性分析研究

【目的】晋祠鱼沼飞梁作为“世界上最古老的立交桥”,凸显着山西古建筑的文化特色。【方法】通过回弹仪对晋祠鱼沼飞梁石柱抗压强度进行测试;依据测绘图纸利用AutoCAD软件进行三维建模,并利用ABAQUS有限元分析软件对其静力荷载及地震作用下的整体稳定性进行数值模拟分析。【结果】结果表明:鱼沼飞梁在静力作用下,构件所受应力远小于允许值,地基沉降量较小,趋于稳定;在地震作用下,结构受力均匀对称,顶面位移最大,石柱第三主应力主要集中于柱脚与柱顶,且沿地震波加载方向,斜截面发展,所受应力也小于允许值,具备较好的抗震稳定性。本研究可为鱼沼飞梁日后的保护和修缮工作提供参考依据。

全球重要农业文化遗产桑基鱼塘时空格局演变和驱动因素

浙江省湖州市南浔区是目前桑基鱼塘保留最完整、规模最大的区域之一,该地的桑基鱼塘系统被列入全球重要农业文化遗产。随着社会经济发展、消费需求改变、农业现代化生产,桑基鱼塘系统的生产方式、经济及服务价值等发生了重大变化。本文利用遥感影像、社会经济等数据对1975—2019年南浔区桑基鱼塘的时空格局演变和驱动因素进行了研究,主要结果如下:1)从规模变化上看,鱼塘快速扩张,桑园明显减少,水田剧烈萎缩,桑基鱼塘规模明显减小,基塘比例严重降低;从形态变化上看,鱼塘呈集聚化、规模化趋势,桑园和水田呈破碎化趋势,且鱼塘逐渐脱离传统桑基鱼塘系统布局特色而独立存在。2)2012—2019年,鱼塘养殖的经济效益远高于蚕桑养殖和水稻种植,是导致桑园、水田明显萎缩及鱼塘大规模扩张的主要驱动力。因此,通过全球重要农业文化遗产的建立来进一步加强桑基鱼塘系统的保护与传承是非常必要的,也是支撑湖州市南浔区农业可持续发展的重要举措。

乡村振兴视域下农耕文化复兴路径研究——以湖州荻港桑基鱼塘为例

农耕文化作为中华文化之母,拥有悠长的历史,是人类文明不断向前发展演变的重要因素和基础。该文将基于乡村振兴战略背景,对如何让传统农耕文化焕新发展并赋能乡村振兴进行研究。在城市化、工业化不断发展的当下,透过传统农耕文化所面临的传承、认同、没落等方面的生存困境,剖析其与乡村振兴的内在关联,并以湖州荻港桑基鱼塘作为具体研究对象,窥探并总结传统农耕文化的传承与发展,为研究乡村文化振兴提供历史经验。该文分别从文化内在塑造文化场域、特色文化产业链形成融合布局开发及多方聚合协同治理3方面切入,探寻乡村振兴视野下农耕文化的复兴路径,为农耕生存空间扩容。

水位变化下长江下游围垦集约养殖鱼塘消落带温室气体排放影响机制:以南京地区为例

为了研究水位变化对淡水养殖鱼塘消落带沉积物温室气体(GHGs)排放的影响,结合前期野外观测数据,选取南京市温室气体高排放的养殖鱼塘消落带沉积物为研究对象,通过室内微宇宙培养实验,设置高水位、低水位、先高后低和先低后高4个不同水位的处理组,并结合气相色谱法、紫外-可见光光谱法和三维荧光光谱技术(3D-EEMs)等方法探讨其影响机制。结果表明:静态高水位组的CH_(4)累积排放量是静态低水位组的3.46倍,静态低水位组的CO_(2)累积排放量是静态高水位组的1.21倍,静态低水位组的N_(2)O表现为持续吸收。动态组中,水位上升和下降均促进了CO_(2)、CH_(4)和N_(2)O的排放,其中水位上升组的CO_(2)和CH_(4)累积排放量分别是静态低水位组的1.15倍和2.53倍,水位下降组CO_(2)、CH_(4)和N_(2)O累积排放量分别是静态高水位组的1.25、1.08倍和2.84倍。研究表明:水位变化差异和变化影响下的消落带沉积物溶解性有机质对温室气体的产生和排放起到了关键作用。CO_(2)排放与可溶性有机碳浓度相关性最高。CH_(4)排放与C/N呈显著负相关关系,同时与溶解性有机质定性光谱指数[腐殖化指数(HIX)和SUVA254(254 nm波长处的紫外吸光度与总有机碳的比例)]有显著相关关系。N_(2)O的排放主要受水位变化引起的硝化与反硝化作用的影响。

大宗淡水鱼坑塘设置网箱养殖大口黑鲈试验

在河北地区采用在大宗淡水鱼坑塘中设置网箱养殖大口黑鲈(Micropterus salmoides)的模式,4月份网箱放养大口黑鲈鱼种75尾/m^(2),规格126~158 g/尾;10月份网箱产量41.44 kg/m^(2),平均规格595 g/尾,成活率92%,饲料系数1.33,利润294.48元/m^(2),投入与产出比1∶1.32。网箱外坑塘大宗淡水鱼鱼种平均产量11115 kg/hm^(2),饲料系数为1.08。该模式当年投放大规格大口黑鲈鱼种,可当年养成,当年销售见效益。

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.

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.

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.

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.

桑基鱼塘农业文化遗产景观演变——以湖州市菱湖镇为例

揭示太湖南岸湖州桑基鱼塘农业文化遗产的景观演变和现状问题。通过文献研究、envi水体提取、图解分析、对比分析和实地调查,分析了菱湖镇桑基鱼塘农遗的历史变迁、水体变化、肌理形态变化与经营模式变化。发现:(1)菱湖镇桑基鱼塘系统历经萌芽诞生期、开拓发展期、进步繁盛期和调整发展期四个阶段;(2)基塘系统的水体景观面积扩张,侵蚀基面;(3)基塘肌理形态趋于密集规整,要素组合多为线状、面状,城市建设蔓入农业用地;(4)经营模式多元化,生态循环受到破坏。桑基鱼塘农业文化遗产的传统模式受到很大冲击与破坏,未来的保护与发展有待更多可持续性探索。