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1.
Pond experiments with one treatment per pond are discussed for their sources of variability. Replication of treated ponds, randomization of treatment allocation to ponds and the importance of independence between ponds are emphasized for efficient estimation of both treatment and inherent pond differences. Appropriate models are given for the analysis of data for pond experiments with whole-pond treatments. Corresponding analyses of variance are given to illustrate the estimation of differences between treatments, between ponds and between fish within ponds. Appropriate significance tests for treatment effects are demonstrated to avoid pseudoreplication, the incorrect use of within-pond variation. Using a fertilizer experiment, simple graphical methods are presented for examining between- and within-pond variation to identify ponds with unusual data, and to determine adequacy of design and appropriate analyses.  相似文献   

2.
One- and two-season cross-over designs are compared with completely randomized designs for their potential use in pond aquaculture experiments. Cross-over designs allow treatment comparisons to be made within the same pond, removing much of the between-pond variability. Different treatments are applied consecutively to the same pond. The one-season design involves splitting the season into two periods and applying different treatments in each period. The fish growth in each of the periods is compared taking account of both pond and period differences. The two-season design compares the harvest weight or growth over a whole season in consecutive seasons. Each of the designs is explained further. Data from uniformity trials are used to make these comparisons. Trials on the use of buffalo manure supplemented with urea and triple sulphate, which were completed in consecutive seasons, are used to verify the conclusions. The advantages and disadvantages of each design are discussed.  相似文献   

3.
Split ponds are recently developed pond‐based aquaculture systems that allow intensification of catfish aquaculture. Successful industry‐wide adoption of newly developing technologies like split‐pond systems will depend upon their productivity and cost efficiencies. Costs and production performance of the following three split‐pond design scenarios were monitored in Arkansas and Mississippi: (1) research design developed at the Thad Cochran National Warmwater Aquaculture Center, Stoneville, Mississippi; (2) waterwheel design tested on commercial catfish ponds; and (3) screw‐pump design tested on commercial catfish ponds. An economic engineering approach using standard enterprise budget analysis was used to develop estimates of breakeven prices (BEPs) ($/kg) for producing foodsize hybrid catfish (♂Ictalurus furcatus × ♀Ictalurus punctatus) for each scenario. Estimates of BEPs of hybrid catfish raised in split ponds ranged from $1.72 to $2.05/kg. The cost of catfish production in split ponds was sensitive to yield, fish prices, and feed prices. Annual net cash flows from both commercial split‐pond systems were high and sufficient to make the investment profitable in the long run. Feed price, feed conversion ratio, and yield contributed the most to downside risk of split ponds.  相似文献   

4.
The present paper illustrates the need for greater pond replication in pond experiments. It demonstrates that increasing the number of fish sampled in each pond will not reduce the number of ponds needed when treatment effects are estimated. Sampling bias, skew distributions and heterogeneous fish populations are discussed in relation to fish sample sizes. When it is impossible to increase the number of replicate ponds, several methods of accounting for the pond variability are suggested.  相似文献   

5.
A dynamic model of dissolved oxygen behavior in a stillwater aquaculture pond is presented. Using theories and principles that have been established for aerobic waste-water treatment ponds and shallow lakes and reservoirs, equations were developed to describe the short-term dissolved oxygen fluctuations of an aquaculture pond. Components considered in this model include the consumption and production of oxygen by phytoplankton, fish, detritus, and the process of reaeration. Factors affecting these components can be specified by the user; these include meteorologic and geographic data, and phytoplankton, fish, and detrital characteristics. After comparing the model to field data and analyzing the sensitivity of its components, areas of research which may have an impact on pond management are identified.  相似文献   

6.
我国淡水池塘养殖投入产出分析与发展对策   总被引：1，自引：0，他引：1  
淡水池塘养殖是我国水产养殖业的重要组成部分,其投入产出效益关系一直备受关注。在对10个省份淡水池塘养殖投入产出数据调研的基础上,分析了产出与投入之间的关系,得出结论:(1)典型相关分析发现,淡水池塘养殖产出与投入第一对典型相关变量的相关系数达到强相关水平,值为0.961 3,其中,反映产出的典型变量主要由成鱼收入决定,反映投入的典型变量主要由饲料和苗种费用决定;(2)样本区域淡水池塘养殖产出投入比值介于0.76~1.65之间,效益相差较大,其中浙江最高、辽宁最低。建议通过加大中低产池塘标准化改造力度、构建生态养殖模式及提高养殖合作组织化程度等措施,促进实现我国淡水池塘养殖可持续发展目标。  相似文献   

7.
ABSTRACT: To quantify the contribution by cocultured animals to waste assimilation in an intensive shrimp farm in Thailand, the food web structures of the macrobenthos in a reservoir pond, a shrimp culture pond and water treatment ponds were examined using the stable C and N isotope ratio technique. Seawater for aquaculture was drawn from a creek, and stored in a reservoir pond, used for farming the banana prawn Fenneropenaeus merguiensis in culture ponds, and then recycled through treatment ponds where the green mussel Perna viridis was cultured to remove organic wastes discharged from the farming. The clam worm Nereididae sp. and the mud creeper Cerithideopsilla cingulata in the culture pond had δ 13C values of −21.0‰ and −18.4‰, respectively, suggesting that shrimp feed (mean δ 13C = −20.7‰) was the main food source for these species. The δ 13C analysis also suggested that sediments (−23.7‰) in the reservoir pond and particulate organic matter (POM) (−24.0‰) and/or sediments (−25.0‰) in the treatment pond supplied carbon for most macrobenthic animals. However, green mussels in the treatment pond had a mean δ 13C value of −20.5‰, suggesting that shrimp feed was the main food source for this species.  相似文献   

8.
ABSTRACT:   A pelagic bacterial community structure was examined in experimental intensive shrimp culture ponds that have a shrimp–mangrove complex aquaculture system, an extensive shrimp culture pond and a mangrove area in Thailand by denaturant gradient gel electrophoresis analysis of polymerase chain reaction amplified partial 16S rRNA genes. Bacterial community structure in the intensive shrimp culture ponds was distinguishable from that of the mangrove area. In the extensive shrimp culture pond, the bacterial community structure resembled that in the mangrove area, but bacterial abundance was as great as that in the intensive shrimp culture ponds. Among the intensive shrimp culture ponds, the bacterial community structure was different between a closed culture system and a shrimp–mangrove complex culture system. Moreover, the bacterial community structure in mangrove planted ponds was close to those in the intensive shrimp culture ponds when shrimp culture was conducted, but it was close to those in the mangrove areas without shrimp culture. These results suggest that intensive shrimp culture with shrimp feed input affects the bacterial community structures in pond water.  相似文献   

9.
Water use and conservation for inland aquaculture ponds   总被引：2，自引：0，他引：2  
The general hydrological equation, inflow = outflow ± change in storage, can be used to make accurate estimates of water use by ponds for inland aquaculture projects. The primary inflows are precipitation, runoff and regulated water additions. The main outflows are evaporation, seepage, overflow after storms and intentional discharge. Water conservation measures such as maintaining storage capacity in ponds equal to the normal, maximum daily precipitation, reduction in seepage beneath dams and through pond bottoms, fish harvest without draining ponds, and water re-use are discussed. Even with the implementation of water conservation measures, pond aquaculture is a water- intensive endeavour which consumes more water per unit of area than irrigated agriculture. However, the value of aquacultural production per unit of water used greatly exceeds that of irrigated agriculture. Reduction in effluent volume is the most effective water saving means, and not only reduces water consumption but also reduces the pollution potential of pond aquaculture.  相似文献   

10.
研究了循环水对池塘中氮、磷含量、浮游生物种群结构及其相互关系的影响。结果显示:从循环塘中共鉴定出浮游植物93种,隶属6门47属;非循环塘中共鉴定出浮游植物100种,隶属6门48属,循环塘与非循环塘均以绿藻门种类最多,分别占各塘种类总数的40.86%、42%。两塘中浮游植物的密度和生物量分别为:循环塘为247.68～1133.31(×104ind/L)和3.07～10.83 mg/L;非循环塘为511.68～1773.3(×104ind/L)和4.48～17.34 mg/L。循环塘浮游植物的密度和生物量比非循环塘要低,且差异性显著(P<0.05)。循环水鱼塘中共检出浮游动物33属42种,非循环水池塘68属88种,在试验期间两塘中浮游动物的优势种主要是由原生动物和轮虫组成,其种数变化顺序为原生动物>轮虫>枝角类和桡足类。循环塘中原生动物和轮虫分别占浮游动物总种类数的52.38%、33.34%;而非循环塘中原生动物和轮虫分别占浮游动物总种类数的42.05%、48.86%。其中循环塘72～708.11 ind/L和0.41～1.69 mg/L;非循环塘152.9～208.20 ind/L和0.26～0.46 mg/L。循环塘浮游动物的密度和生物量显著高于非循环塘(P<0.05)。循环塘与非循环塘中浮游植物的Shannon-Wiener指数分别为介于1.39～1.62和1.16～1.48之间,两塘中浮游动物的Shannon-Wiener指数分别为介于0.50～1.95和1.08～1.45之间。结果表明:循环水对养鱼池塘水体中浮游生物的出现率、丰度和生物量影响较大。  相似文献   

11.
高位池通常采用中央排污口排污,排污口上的排污装置是高位池的重要部件,其构造直接影响排污效果,是高位池养殖成败的重要因素。为解决传统排污口排污易堵塞和无法吸排底部沉积物的问题,研制了侧排式排污口装置SC-1、SC-2和顶排式排污口装置SD-1,在生产中应用并实测其排污效果。试验采用分时段测定排出口流速和总氮的方法,研究3种新型排污口的应用效果。结果显示,在养殖前期,SC-1型和SC-2型排污口装置的排污性能均优于SD-1,侧排式排污口装置的单次累计排氮量比顶排式的提高18.9%(P0.05)。通过改进中央排污口装置构造,可显著提高排污效率。研究表明,侧排式排污口装置对构建低换水率高位池对虾养殖模式、实现低换水量养殖,具有积极意义。  相似文献   

12.
The industrial aquaculture pond system has gradually replaced the use of traditional earthen pond, as it causes less pollution and is more economical. In this study, an industrial ecological purification recirculating aquaculture system consisting of the water source pond, high‐density culture ponds, a deposit pond, and ecological purification ponds for channel catfish cultivation was established. Twelve water samples from different ponds were sequenced, and the bacterial communities were analysed. The abundances of Cyanobacteria and Merismopedia varied in different functional ponds of the system. The water quality was stable after two months of cultivation at 1.89 ± 0.22 mg/L total nitrogen, 1.1 ± 0.08 mg/L NH4‐N and 0.43 ± 0.1 mg/L total phosphorus. The fish weight increased in a nearly linear manner, reaching 237.63 ± 23.8 per fish at day 120. An analysis of the environmental parameters, water quality and fish weight suggested that the system had an effective water purification process. Canonical correspondence analysis showed that the community was affected at the genus and phylum levels by different environmental parameters. We identified several dominant beneficial bacteria with nutrient removal abilities. Overall, our results demonstrated that the ecological purification recirculating aquaculture system had notable effects on water quality improvement and promoted changes in bacterial populations. These results provide important information on the microbial ecology of pond industrial eco‐aquaculture systems.  相似文献   

13.
The sensitivity of any treatment comparisons in pond experiments is often limited by large variability among ponds. Standard techniques of increasing the number of replicate ponds to account for the large variability may be inappropriate as only a limited number of ponds may be available for any one experiment. This paper considers various ‘balanced incomplete block’ designs and compares their use with ‘completely randomized designs’ and ‘randomized complete block’ designs. With simulated data, it is shown that ‘balanced incomplete block’ designs can reduce the standard error of a treatment estimate by as much as 50%, and reduce confidence intervals by 25%, although increases of similar sizes may be experienced. The pattern of allocation of blocks to ponds by neighbour or by pond number shows no clear distinction in estimation improvement. Where missing ponds occur a large increase in imprecision may be experienced. These results are supported by data from non‐uniformity experiments. Further work is needed to explore block structures for specific types of treatment that may influence the patterns of variability to different extents.  相似文献   

14.
复合池塘循环水养殖系统生态足迹分析   总被引：2，自引：0，他引：2  
生态足迹模型已广泛应用于可持续发展的评估中。将生物塘、人工湿地、生态沟渠等生态工程系统与传统养殖塘有机结合而构建形成的复合池塘循环水养殖系统,作为一种新养殖模式,它具有循环微流水养殖、种养结合、水陆交互作用的特点。本文运用生态足迹方法对这一新养殖模式进行了定量分析。结果表明:就单位利润生态足迹量而言,复合池塘循环水养殖模式为2.92 ghm2/万元,而传统池塘养殖模式为4.91ghm2/万元,复合模式具有更高的生态经济综合效益,更符合可持续发展要求。  相似文献   

15.
A production model is presented for semi-intensive freshwater crayfish culture ponds incorporating detrital forage. The conceptual model is developed from five submodels of trophic-dynamic interactions within the pond ecosystem. The model includes microbially enhanced detrital forage (MEDF) produced from plant matter grown in the pond as a significant component of nutrition. The model is proposed as an aid to understanding pond-based aquaculture techniques that rely upon manipulating the characteristics of MEDF. The significance of MEDF as a source of nutrition in aquaculture is discussed.  相似文献   

16.
Bivalves have been proven to be an inexpensive method for removing suspended solids, dissolved nutrients, and controlling algal growth through suspension feeding. The freshwater mussel, Elliptio complanata, is one of the most abundant species in Delaware, and it is additionally favorable for this experiment because of its hardiness against environmental stress and its filtration efficiency. This study examines the possibility that biomechanical filters such as E. complanata can supplement existing chemical and mechanical filtration regiments in aquaculture pond management. Twelve earthen aquaculture ponds located at the Delaware State University were stocked at a density of 4,000 catfish (Ictalurus punctatus) per hectare. Four different concentrations (0, 75, 150, and 300) of E. complanata were placed in trays within the ponds with three replicates of each concentration. The trays were suspended 15 cm below the surface of the water for a period of five months. Fish were fed a 32% protein diet twice daily at a rate of 1% of their body weight. Water quality was analyzed weekly while fish and mussel growths were measured biweekly. Results from water quality parameters varied significantly and were not conclusive based on the data obtained in this study. Water quality did not improve within the mussel treatment ponds during the course of this study and was found to be significantly below that of control ponds for all of the water chemistry parameters measured, with the exception of ammonia. Catfish in the 150 mussel treatment ponds grew the fastest; the 75 mussel treatment provided the most growth in mussels; and the 300 mussel group maintained the highest mussel survivorship. Although there were differences between ponds, fish growth and survivorship were not significantly different between treatments. While our mussel densities may have not been sufficient, their placement within the water column may have added additional stress. Being removed from the sediment can result in a decreased clearance rate in a benthic species such as E. complanata. This study may not have been conclusive in proving that mussels can be used to maintain water quality in aquaculture ponds, but we did see positive growth and survivorship of mussels and fish that indicated that the mussels were thriving in the aquaculture pond setting. This study may show that aquaculture ponds provide a suitable habitat in which propagated mussels may be held until their release into native areas.  相似文献   

17.
夏季高温时,养殖水体水华现象频繁发生,给养殖业带来巨大的损失。常见水生植物释放的活性物质在低浓度下可以起到抑藻作用,对藻类调控具有重要意义。本研究采用实验室静态模拟方法,取养殖池塘暴发蓝藻水华的水体,与沉水植物金鱼藻(Ceratophyllum demersum)及篦齿眼子菜(Potamogeton pectinatus)进行共培养,研究这2种沉水植物对养殖水华水体营养水平、藻类生长、藻类结构及浮游藻类生物多样性的影响。结果显示,金鱼藻和篦齿眼子菜可显著降低水华水体氮、磷等营养水平(P<0.05);金鱼藻和篦齿眼子菜可有效抑制水华蓝藻(Cyanobacteria)生长,尤其对颤藻和微囊藻(Microcystis sp.)效果显著(P<0.05),且篦齿眼子菜对水华蓝藻抑制效果更为显著。实验结束时,篦齿眼子菜培养组藻密度下降93.6%,生物量下降98.9%,叶绿素a含量下降60.5%;金鱼藻培养组藻密度下降72.5%,生物量下降86.8%,叶绿素a含量下降54.3%;金鱼藻和篦齿眼子菜的存在可促进养殖水体浮游藻类生物多样性增加,且金鱼藻提高浮游藻类生物多样性效果更显著。金鱼藻培养组浮游藻类生物多样性升高98.4%,篦齿眼子菜培养组浮游藻类生物多样性升高50.3%。本研究结果可为未来生态养殖提供理论依据和参考。  相似文献   

18.
水产养殖过程中,池塘生态系统可分为自成熟期和人工维持期。在养殖容量提高的情况下,养殖生物呼吸需氧量在不断增加,缺氧条件下有机物分解成有害物质,影响养殖生产。维持池塘生态系统稳定的主要工程机制为:通过上下水层交换、平衡营养元素等方法,强化光合作用,提高营养物质转化规模,提升初级生产力;形成生态增氧为主、机械增氧为辅的高效增氧机制。以中国养殖池塘生态系统为研究对象,分析探讨养殖池塘生态机制、水体溶氧理论、增氧机作用机理、不同类型增氧机的机械性能等,提出了大宗淡水鱼混养池塘及几种典型单养池塘增氧机配置方式,从而为池塘养殖系统增氧机的配置提供技术参考。  相似文献   

19.
ABSTRACT:   An experiment in which water was circulated between shrimp aquaculture ponds stocked with 10 000 or 20 000 PL-15 stage Penaeus monodon , and mangrove enclosures each planted with 476 Rhizophora mucronata per enclosure, was carried out at the Samut Songkhram Coastal Aquatic Research Station, Faculty of Fisheries, Kasetsart University, Thailand. Shrimp survival rate was significantly higher ( P  < 0.001, Fisher's exact test) in ponds where 10 000 larvae was stocked and water was exchanged with the mangrove enclosure, compared with the control pond with no water exchange, over the 136 day experimental period. Phosphorus transport to the mangrove enclosure was estimated to be 0.41 kgP and 0.18 kgP over the experimental period and change in phosphorus content in mud was reduced there compared with the control pond. A load reduction effect to the environment was confirmed in this aquaculture system with mangrove enclosure compared with the phosphorus budget in the control pond, and 6.2 or 8.9 ha of mangrove area was estimated to be required by 1 ha shrimp ponds to fully process the phosphorus.  相似文献   

20.
微生物群落是养殖池塘生态系统的重要组成部分,了解环境微生物群落结构和功能,可有针对性地进行养殖环境微生态调控。在不同季节采集尼罗罗非鱼（Oreochromis niloticus）和斑点叉尾鮰（Ictalurus punctatus）池塘水样,分析硝酸盐氮(NO3-N)、亚硝酸盐氮(NO2-N)、氨氮(NH4-N)、总氮(TN)和总磷(TP)等理化指标,利用Biolog-Eco微平板技术分析水体中微生物对各类碳源代谢的平均颜色变化率,利用高通量测序技术分析其菌群结构。结果表明,1月淡水养殖池塘水质和菌群结构不同于其他采样时间,养殖鱼类种类对池塘理化指标和微生物菌群结构影响不大。不同采样时间的池塘理化指标差异显著,同一采样时间不同养殖鱼类池塘的理化指标之间无显著差异。其中,1月尼罗罗非鱼池塘中的NH4-N含量高于其他月份,且显著高于4月和7月（P<0.05）;1月TP含量显著高于4月、7月和10月（P<0.05）。1月斑点叉尾鮰池塘的TP和NO3-N含量显著高于其他3个月份（P<0.05）。Biolog-Eco微平板技术检测到尼罗罗非鱼和斑点叉尾鮰池塘中的微生物群落对碳...  相似文献   

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