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...     

Engineering and economic considerations for aquaculture development

The development of an economically successful aquaculture site requires both engineering and economic evaluation. As part of a study for the Southern Colorado Economic Development District, considerable data on potential sites were collected and evaluated on the bases of site, climatic, engineering and economic considerations.Available resources, pond requirements, construction and operation costs and design requirements were integrated for the evaluation of the most feasible system for the area. Economic summaries were prepared outlining total expected costs and rates of return on production of Macrobrachium rosenbergii prawns.     

Temperature modeling of a land-based aquaculture system for the production of Gracilaria pacifica: Possible system modifications to conserve heat and extend the growing season

Temperature control is a major cost for numerous aquaculture systems. Solar thermal engineering techniques can be used to identify inexpensive methods for conserving and capturing heat. Gracilaria pacifica, also known as the culinary ingredient ogo, is currently grown in land-based tanks at a site in Goleta, CA where influent sea water temperatures infrequently reach the 21–28 °C range that provides for optimal growth. The major objective of this study was to explore various designs of a G. pacifica tank culture system that maintain optimal water temperature year round to maximize growth. A model was constructed and calibrated by comparing results to a one-third scale pilot system operated in Davis, CA. For model calibration the most sensitive parameter such as cover optical properties were adjusted first and less sensitive parameters were adjusted later. The pilot system consisted of six tanks, three insulated with foam and a clear polyethylene cover (experimental), and three uninsulated and uncovered (controls). The model had weather data inputs including air temperature, humidity, wind speed, and solar radiation. The model was then compared to a full-scale system operated in Santa Barbara during the winter. The experimental pilot system was 4.93 °C warmer than the control pilot system under optimal weather conditions. The full-scale experimental system was 2.80 °C warmer than the control system under non-ideal conditions. The model demonstrated predictive accuracy under most weather conditions. Furthermore the model is robust enough to accept estimated values for many inputs and still produce accurate results, this suggests a simpler model may be feasible. A polyethylene cover and insulation are not sufficient in general for raising the water temperature to the optimum range during the winter; they may be during other times of the year when more solar energy is available, thereby extending the growing season.     

Water use and conservation for inland aquaculture ponds

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.     

Technical efficiency of carp production in Nepal: An application of stochastic frontier production function approach*

Abstract

Modern aquaculture is a relatively new activity among Nepalese farmers and a small contributor to the economy. Given the abundance of water resources and fish species, rising demand for fish, and its high profitability, aquaculture has potential for future expansion if it is given appropriate attention from the government. In Nepal, productivity in aquaculture is much lower compared to other countries in the region, which suggests that there is potential for increased fish production through technological progress and improvement in farm‐level technical efficiency. However, no formal analysis has yet been conducted to assess the productive performance of Nepalese aquaculture and its potential for future improvement. Against this background, this paper examines the technical efficiency and its determinants for a sample of fish pond farms from the Tarai region of the country using a stochastic production frontier involving a model for technical inefficiency effects. The estimated mean technical efficiency is 77%, with intensive farms being more efficient than extensive farms. The adoption of regular fish, water, and feed management activities has a strong positive effect on technical efficiency.     

养殖池塘增氧机制与装备性能比较研究

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。     

Water and nutrient budgets of ponds in integrated agriculture–aquaculture systems in the Mekong Delta, Vietnam

A participatory on-farm study analysed water and nutrient budgets of six low and four high water-exchange ponds of integrated agriculture–aquaculture (IAA) farms in the Mekong delta. Water, nitrogen (N), organic carbon (OC) and phosphorus (P) flows through the ponds were monitored, and data on fish production and nutrient accumulation in sediments were collected during a fish culture cycle. Results showed that, on average, only 5–6% of total N, OC or P inputs introduced into ponds were recovered in the harvested fish. About 29% N, 81% OC and 51% P accumulated in the sediments. The remaining fractions were lost through pond water discharges into adjacent canals. Fish yields and nutrient accumulation rates in the sediments increased with increasing food inputs applied to the pond at the cost of increased nutrient discharges. High water-exchange ponds received two to three times more on-farm nutrients (N, OC and P) while requiring nine times more water and discharging 10–14 times more nutrients than the low water-exchange ponds. Water and nutrient flows between the pond and the other IAA-farm components need to be considered when optimizing productivity and profitability from IAA systems.     

基于环境容纳量的区域性养殖容量评估

针对淡水养殖池塘养殖水体及周边水域水质日趋恶化的现状,为了保证水产养殖业的可持续发展,亟需开展养殖容量相关方面的研究,将主要养殖品种面积和密度控制在最佳的范围内。以浙江南浔区为研究区域,通过调查该区域水环境现状和6种主要养殖模式养殖特点,计算了该区域水体总磷的环境容纳量,再根据单位养殖模式排污量初步评估了该区域主要养殖品种的养殖容量。结果显示:(1)南浔区水环境的磷为限制因子;(2)常规鱼、大口黑鲈(Micropterus salmoides)、乌鳢(Ophiocephalus argus)、翘嘴鲌(Culter alburnus)、中华鳖(Trionyx Sinensis)和青鱼(Mylopharyngodon piceus)单位产磷量分别为0.26、0.70、0.73、0.17、0.33和0.22 g/kg;(3)在II类水质前提下,常规鱼、大口黑鲈、乌鳢、翘嘴鲌、中华鳖、青鱼养殖塘可接受的最大磷负荷为7.38、5.79、2.36、1.82、1.51、2.52 t,其对应养殖容量分别为28 370、8 271、3 236、10 698、11 648、9 685 t;(4)养殖容量模型参数敏感性分析表明,磷滞留系数、换水系数和外河磷浓度敏感度系数分别为0.365、0.364和-0.271;区域养殖容量的合理评估可为生态渔业的发展提供科学依据。     

Simulation of future dissolved oxygen distribution in pond culture based on sliding window-temporal convolutional network and trend surface analysis

Dissolved oxygen (DO) is a key ecological factor to measure the quality of water in the aquaculture. As the pond water body is affected by the breeding environment, the spatial distribution of DO shows a certain law in the entire pond. Therefore, to simulate the distribution of DO in aquaculture waters and grasp the temporal and spatial variation of DO is the key to achieving precise regulation of DO. For this purpose, this paper proposed a method for simulating the temporal and spatial distribution of DO in pond culture based on a sliding window-temporal convolutional network together with trend surface analysis (SW-TCN-TSA). This paper first utilized SW to construct DO data sets with different prediction durations, and then used the improved TCN model to realize one-dimensional time series prediction for DO at single monitoring point. Based on the prediction results of DO, a TSA method was performed on the predicted values of DO at the extreme moments of all discrete monitoring points, so as to realize the simulation of the temporal and spatial distribution of DO in the pond. Experimental results show that the SW-TCN model has better prediction performance for one-dimensional time series prediction of DO. Compared with traditional deep networks, such as CNN, GRU, LSTM, CNN-GRU and CNN-LSTM, the values of evaluation indicators (MSE, MAE and RMSE) have been greatly improved. In the process of trend surface fitting, all fitting R² of DO at different water depths are higher than 0.9, indicating that the TSA can accurately reflect the temporal and spatial distribution of DO. This method can provide a basis for the prediction and early warning of DO in the three-dimensional space of the pond and has high practicability in aquaculture.     

Effects of modified pond management on limnological parameters in small‐scale aquaculture ponds in mountainous Northern Vietnam

In mountainous Northern Vietnam, traditional pond aquaculture is part of the integrated farming activity contributing to food safety and to income generation for small‐scale farmers of ethnic minorities. Traditional pond management consists of a polyculture of macro‐herbivorous grass carp with 3–5 other fish species that are cultured in small ponds with constant water flow through. The main limitations to production are species‐specific mass mortalities of grass carp, a poor feed base especially for all species but grass carp, and poor water quality. In this study, we compared the traditional pond management to a semi‐intensive pond management that was based on the traditional management system but included changes designed by researchers to increase fish production. The modifications consisted of water inflow control, supplemental fertilization and feeding, and a polyculture dominated by common carp. The changes in management significantly reduced the turbidity and increased oxygen supply, as well as the natural food base within the pond. These changes in pond management provide farmers with the possibility to improve their pond aquaculture scheme and overcome previous limitations.     

复合池塘循环水养殖系统生态足迹分析

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。     

对虾高位池中央排污口装置排污效果研究

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。     

A Derived Climatology of Water Temperatures for the Mississippi Catfish Industry

A 36 year (1951–1986) record of water temperatures in Mississippi catfish ponds is synthesized from relationships with existing air temperature records. Multiple regression analysis is used to produce the following predictor equations for morning and afternoon pond temperatures: morning pond temperatures = 2.218 + 0.062(max air temp, day before) + 0.285(min air temp, same day) + 0.561 (afternoon pond temp, day before) (1) afternoon pond temperatures
= 2.071 - 0.068(min air temp, same day) + 0.651 (morning pond temp, same day) + 0.373(max air temp, same day) (2)
The derived pond temperature record is analyzed to produce annual average regimes; daily average, maximum, and minimum temperatures with standard deviations; and probabilities at 10 levels of Occurrence through the year and for each individual month. Applications for the aquaculture industry are presented and evaluated.     

Modelling growth rate of Penaeus monodon Fabricius in intensively managed ponds: effects of temperature,pond age and stocking density

Records of shrimp growth and water quality made during 12 crops from each of 48 ponds, over a period of 6.5 years, were provided by a Queensland, Australia, commercial shrimp farm. These data were analysed with a new growth model derived from the Gompertz model. The results indicate that water temperature, mortality and pond age significantly affect growth rates. After 180 days, shrimp reach 34 g at constant 30 °C, but only 15 g after the same amount of time at 20 °C. Mortality, through thinning the density of shrimp in the ponds, increased the growth rate, but the effect is small. With continual production, growth rates at first remained steady, then appeared to decrease for the sixth and seventh crop, after which they have increased steadily with each crop. It appears that conservative pond management, together with a gradual improvement in husbandry techniques, particularly feed management, brought about this change. This has encouraging implications for the long-term sustainability of the farming methods used. The growth model can be used to predict productivity, and hence, profitability, of new aquaculture locations or new production strategies.     

一株内循环流水养殖池塘光合细菌的分离鉴定及氮磷去除能力的研究

为提高内循环流水养殖池塘净化区域的净化能力,从重庆潼南区内循环流水养殖池塘的底泥中分离纯化得到一株光合细菌(命名为菌株GR01).通过形态学观察、生理生化鉴定、16S rDNA基因序列分析和扫描吸收光谱,对菌株进行分类鉴定.测定菌株GR01在不同温度、不同pH、不同盐度条件下的660 nm处的吸光度(A660),确定其...     

我国水产养殖设施模式发展研究

作为世界水产养殖大国,我国的养殖设施模式要走上可持续发展的轨道,应该在为健康养殖提供进一步保障的前提下,更加注重系统在"节水、节地、节能、减排"方面的功效。养殖池塘、流水型养殖设施、循环水养殖设施和网箱养殖设施是我国集约化养殖的主要设施模式。这些设施在发挥巨大生产力的同时,在养殖水环境控制、水资源利用、生产系统效益、系统对环境的影响等方面,不同程度地存在着问题或矛盾,没能发挥出现代设施系统在健康养殖和产业可持续发展上应有的作用。本文在对以上4种主要养殖设施模式进行分析的基础上,结合养殖设施科技领域的研究成果,提出未来我国水产养殖设施模式的发展方向以及需要解决的重大科技问题,包括池塘工程化生态养殖设施、节水型养殖设施、经济型循环水养殖设施、系统化深水网箱养殖设施等4种发展模式。     

池塘养殖水体中土著反硝化细菌的分离与初步鉴定

池塘养殖水体水质恶化问题日益突出,尽管已有各种商品化微生态制剂,但水质净化修复效果始终未得到有效提高。通过采用定向分离、筛选、扩繁来自原生境的土著有益菌的方法进行生物修复,从而提高养殖废水的净化修复效果;该方法具有针对性强、效果佳、安全性高、成本低以及持续活性时间长、无二次污染等优点。2016年9月,从山西省运城黄河滩涂水产养殖主产区养殖中后期的池塘水体中定向分离筛选得到1株土著反硝化细菌,命名为YJ-1,使用奈氏试剂和格利斯试剂对其反硝化能力进行检测。结果显示,奈氏试剂显示黄色,格利斯试剂显示绛红色,说明在细菌培养24h后发酵液中产生了少部分的铵离子和较多的亚硝酸盐,菌落具有反硝化功能。经16SrDNA序列扩增与测定,片段长度为1 441bp。无根系统发育树分析显示,YJ-1与产酸克雷伯氏杆菌(Klebsiella oxytoca)的同源性最高,YJ-1的分离打破了现有微生态制剂成分大多数为各种商品菌的局势;在水产微生态制剂制备过程中定向加入土著反硝化细菌,可有效降低养殖水体中氨氮与亚硝酸盐含量、减少鱼体发病率;反硝化细菌在水产养殖水质净化、城市污水处理中具有较大的应用前景,本研究为其他土著有益菌的分离、筛选、鉴定及应用提供了可借鉴的思路。     

Agglomeration externalities and technical efficiency: An empirical application to the pond aquaculture of Pangas and Tilapia in Bangladesh

This article analyzes the effects of agglomeration externalities on productivity and efficiency by applying a stochastic production frontier model with a technical inefficiency model to the aquaculture industry. Agglomeration externalities refer to the costs and benefits to firms from clustering. Agglomeration studies within aquaculture have focused on the intensive salmon industry, whereas this study focuses on low-technology, extensive pond aquaculture, representing most farmers in the developing world and using Bangladesh as an empirical case. The results show that there is a positive externality effect of regional industry size on the production possibility frontier and a negative effect on technical efficiency. Farm density enhances efficiency and the farm proximity to output markets decreases efficiency. Thus, policies aimed at increasing aquaculture pond production in developing countries should consider farm locations and their access to input and output markets, all of which affect farm productivity and efficiency.     

EFFICIENCY OF RESOURCE USE AMONG POND FISH FARMERS IN CENTRAL UGANDA: A STOCHASTIC FRONTIER PRODUCTION FUNCTION APPROACH

This article presents the use of a stochastic frontier production function to examine the efficiency of resource utilization in pond fish farming in Uganda. The study draws on data from a field survey administered to 200 small-scale fish farmers in three major fish farming districts in Central Uganda: Mukono, Mpigi and Wakiso. The districts were part of a large aquaculture development project funded by the United States Agency for International Development-Aquaculture and Fisheries Collaborative Research Support Program. Productive efficiency was analyzed using stochastic frontier analysis with a translog production function while assuming a truncated-normal distribution for the inefficiency term. The output variable was total quantity of fish produced, while input variables were quantity or value of inputs used in the production process, namely labor, pond size, stocking density, capital and feeds. The estimated index of resource-use efficiency revealed that small-scale farmers were inefficient in resource allocation by over-utilizing labor with an estimated allocative efficiency index of ?0.94 and grossly under-utilized pond size, feeds and fingerlings with allocative efficient indices of 1.15, 1.64, 3.71, respectively. The results suggest that there is considerable scope to expand output and also productivity by increasing production efficiency at the relatively inefficient farms and sustaining the efficiency of those operating at or closer to the frontier.