桑沟湾养殖海域的水环境特征

本文研究了桑沟湾养殖海域的水环境特征，并与１０年前的历史资料作了比较。该湾各种化学指标的垂直分布均匀；受大面积高密度养殖影响，该湾水动力状况与１０年前相比发生了明显变化，营养物质输送和海水自净能力降低；各种化学指标、初级生产力、营养状况及类型等平面分布和季节性变化都有更加显著的差异。在海带养殖期间，ＩＮ和ＩＮ／ＩＰ始终处于低水平，其季节变化明显受该湾初级生产力制约，故ＩＮ必然成为桑沟湾初级生产的限制因素。另外，海带养殖也加速了其养殖期间湾内水体中ＩＮ的物质循环速率。     

陆基家庭水产养殖对广西南流江、钦江、防城江环境影响的初步研究

陆基家庭水产养殖正逐步成为广西水产养殖产业的重要部分。本文通过对广西南流江、钦江和防城江的水质特性、无脊椎动物群落、硝酸盐吸收和群落呼吸(CR)和总初级生产(GPP)状况的调查,探讨陆基家庭水产养殖污水对该地区3条河流环境的影响。初步研究显示,与参考站点的河水相比,南流江、钦江水产养殖污水中颗粒有机物(POM)、可溶性活性磷(SRP)分别达8.7和10倍、6.9和9.08倍,影响站点分别为1.6和2.7倍、1.4和1.5倍,而防城江污水SRP未见异常,污水点和受影响站点的POM分别为3.2和1.4倍;3条河流中,污水仅对一条河流的底栖无脊椎动物群落影响不太明显,而对硝酸盐吸收影响效果不一致,CR和GPP代谢受影响均明显。结果表明,陆基家庭水产养殖污水造成北部湾广西地区3条河流群落呼吸和初级生产力明显增加,说明了对陆基家庭水产养殖实行最佳生态管理方法的重要性。     

大窑湾水环境因子对筏养太平洋牡蛎的影响

依据１９９５～１９９７年对大窑湾浮筏养殖区水环境主要因子及养殖状况调查，论述二者之间相互关系，初步探明该海区具有贫磷富氮的特性；３年中该湾富营养化程度逐年减弱。初级生产力水平１９９７年〈１９９６年〈１９９５年，面３年中养殖状况为：太平洋牡蛎死亡率１９９５年〉１９９６年〉１９９７年，牡蛎出内率１９９５年〉１９９６年〉１９９７年。     

小窑湾贝类养殖对叶绿素a及初级生产力的影响

对小窑湾双壳贝类筏式养殖海区叶绿素a、海洋初级生产力的调查时认为:贝类养殖密度对叶绿素a值影响较大,从调查站位上看,养殖密度越大,其叶绿素a值相对较低,从养殖海区的季节变化上来看,叶绿素a值与海区双壳贝类的现存量密切有关;而初级生产力除与叶绿素有关外,还与该海区养殖品种收获时的人为扰动有关。     

观音阁水库渔业资源调查报告

2004年对观音阁水库进行了水质、浮游生物和初级生产力的调查与监测,结合相关标准,综合评价了水库水质和初级生产力状况。从氮、磷等指标判定,该水库为中贫营养型。     

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“河北扇贝养殖区环境调查评估及健康养殖模式研究”项目通过专家鉴定2006年7月21日,河北省科技厅组织有关专家,对河北省水产研究所承担的河北省科技厅项目“河北扇贝养殖区环境调查评估及健康养殖模式研究”[编号:04220502]进行了鉴定。该项目自2004年1月开始实施,首次在河北海湾扇贝养殖区进行了较大规模的水文、物理、水化学、浮游生物、叶绿素a、初级生产力、底栖生物、鱼类、污染源等综合环境的调查,以此为基础,进行了河北扇贝养殖区海湾扇贝养殖容量评估,同时进行了健康养殖模式的试验研究,提出了适于河北的扇贝健康养殖模式。专家组认为,该项目对河北海湾扇贝的健康养殖和可持续发展提供了科学依据,研究成果达到国际先进水平。它的实施必将改善我省海湾扇贝的养殖状况,增加渔民的养殖收入,极大地促进我省海湾扇贝的健康发展。(河北省水产研究所孙桂清)“金乌贼人工繁育技术研究”项目通过专家组验收由河北省水产研究所主持的“金乌贼人工繁育技术研究”项目2006年6月15日顺利通过专家组验收。该项目为河北省水产局指令性计划项目,课题编号:冀渔科200601,起止年限为2006年1月—2007年12月。2006年主要进行了孵化试验及幼体培...     

云龙湖水库的理化特性和初级生产力评价

在总结分析1998年云龙湖水库水体理化指标和初级生产力监测资料的基础上，结合相关标准，综合评价了云龙湖水库的水质和初级生产力状况。从总氮、总磷、初级生产力等指标判定，该水库为富营养型水库。     

浅谈忠县水产技术推广的对策

水产技术推广包含水产养殖新技术、新品种、新材料、新工艺的引进、推广，指导水产养殖、鱼病防治技术和水产养殖业产前、前中、产后的服务，开展水产技术培训等方面的内容。其目的在于更新广大水产养殖从业人员的知识和技术水平，促进新技术、新成果转化为生产力，提高水产养殖生产水平和经济效益。     

不同单养和混养海水实验围隔初级生产力的研究

１９９５年和１９９６年夏秋季进行的围隔实验表明投饵养殖时浮游植物毛初级生产力较低，水呼吸相对较高，多数围隔中毛初级生产力／水呼吸〈１，其中混养中国对虾和台湾红罗非鱼的围隔中毛初级生产力较高，而混养中国对虾，台湾红罗非鱼和菲律宾蛤仔的围隔中毛初级生产力最低；在投饵基础上酌情施肥后围隔毛初级生产力同于投饵养殖时，毛初级生产力／水呼吸〉１，但单养中国对虾，对虾与罗非鱼混养和对虾与海湾扇贝或缢蛏混养的围隔     

大亚湾核电站运转前后邻近海域初级生产力及潜在渔获量初步研究

根据1992－1993年、1994－1995年和1998年的现场调查，对核电站邻近海域初级生产力及潜在渔业资源在核电站运转前和运转后的变化进行了初步研究，并讨论了各环境因素对初级生产力的影响。结果表明，核电站运转后，该海域的浮游植物总量、初级生产力及其年生产量均有显著增加，影响初级生产力的主要因子：核电站运转前是水温，运转后为透明度。     

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。     

The Nutrient Profile in Organic Fertilizers

Abstract

In order to manage nitrogen (N) and phosphorous (P) through organic fertilization in aquaculture ponds, it is important to understand the nutrient profile of different animal manures at various concentrations and the respective biological response. The rate of nutrient released from animal manure over time is a key factor in deciding the frequency and quantity of manure required to fertilize ponds. This study was conducted to elucidate the nutrient profile, and its efficiency in terms of primary productivity, of pig, cow, and buffalo manure, at different N:P concentrations in tank. Appropriate concentrations were maintained by using the minimum amount of inorganic fertilizer supplement. This paper also investigated the impact of lime-treated manure, a traditional practice in Vietnam, on primary production (phytoplankton abundance). The average nitrogen (N) and phosphorus (P) content was higher in pig manure (0.54% N and 0.173% P) compared to cow (0.31% N and 0.028% P) and buffalo (0.34% N and 0.013% P). The ammonia release rate increased with increase in N concentration. The average ammonia release rate (all concentrations, 1-2 ppm N) in the pig manure treatment was significantly higher than cow and buffalo manure treatments. Cow and buffalo manures were found to be similar in terms of ammonia release rate. However, soluble phosphorus level was significantly lower in buffalo manure treatments compared with cow manure. The pig manure treatment produced maximum soluble phosphorus levels in the tanks. The primary productivity obtained at various concentrations (1-2 ppm N:0.5 ppm P) did not differ significantly (P > 0.05) in cow and buffalo manure treatments. The primary productivity performance of pig manure was highest amongst the manure types tested. The 1 ppm N:0.5 ppm P concentration from pig manure yielded the maximum average (1.64 mg C/L) net primary productivity. Based on the primary productivity pattern in the tank, which had a significant correlation with nutrient release rate for all manures tested, the frequency of fertilizer application appeared to be most suitable every 8-10 days. However, increasing the frequency of manure application based on the level of nutrient available in the water will provide more control on nutrient and water quality management for pond aquaculture systems. This level of monitoring may not be practical for regional farmers.     

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。     

桑沟湾增养殖水文环境研究

对桑沟湾大规模开展增养殖前后的水文环境作了研究。由于大面积高密度养殖，桑沟湾的水动力状况和１０年前相比发生了明显变化，潮流速度减缓了５０％，水交换率降低了１．７％，海湾海水半交换周期延长了１１个潮周期。营养物质输送和海水自净能力受到严重影响。部分养殖品种产量下降，表明养殖容纳量已达饱和状态。和其他海湾相比，桑沟湾的水交换条件还是比较好的，只要科学合理地设置养殖品种和养殖密度，仍不失为一个重要的增养     

A REVIEW OF PRODUCTION FRONTIER RESEARCH IN AQUACULTURE (2001–2011)

Most research works on the production frontier in aquaculture focus on efficiency measurement using either Stochastic Production Frontier (SPF) or Data Envelopment Analysis (DEA). The studies on productivity growth in aquaculture were limited, perhaps due to lack of time-series data. Nevertheless, total factor productivity analysis (TFP) in fish farms has started gaining popularity in recent years. In addition, the majority of the efficiency studies have centered on technical efficiency analysis but substantial increases in the output levels can be fully realized through improving overall economic efficiency. Therefore, this review suggests that future research should estimate all three efficiency indices (i.e., technical, allocative and economic efficiencies).     

Estimation of primary productivity from diel nitrate uptake measurements of the water hyacinth Eichhornia crassipes in an aquaculture system

The primary productivity of the water hyacinth Eichhornia crassipes was estimated from diel measurements of NO₃N uptake in an aquaculture system using a continuous, automated nutrient analyzer apparatus. Productivity values obtained by this method agreed favorably with those made by directly harvesting the biomass. Since productivity measurements based on harvesting methods would be impractical on a large scale, the use of diel nutrient uptake measurements would be a significant improvement for proper management of aquatic macrophytes in an aquaculture system. There were few diel changes in NO₃N uptake by Eichhornia, a fact which is potentially beneficial to this species not only to its ecological success in its natural ecosystem, but also to its ability to remove nutrients as a component in tertiary sewage treatment.     

Economic impacts of climate change: profitability of freshwater aquaculture in China

Aquaculture is threatened by the climate change which includes changes in temperature, precipitation, drought, storms and floods. The socio‐economic impacts of climate change on aquaculture are difficult to assess due to the uncertainties regarding the extent and rate of predicted changes. By including bond indexes as climate change variables, this study constructed a provincial‐level panel data set to estimate the profits and productivity of the Chinese aquaculture. Results indicate that aquaculture production has heterogeneous responses to climate change. However, the majority of climate variables, including extreme weather events and long‐term climate changes, strongly affect aquaculture profits. Future research needs to focus on designing suitable adaptation measures in an interdisciplinary setting to address the challenges from natural risks and economic volatility.     

Aquaculture and poverty alleviation in Ben Tre Province,Vietnam

Research results on the effects of aquaculture on poverty alleviation have been mixed. We use Tobit, simulation models and cross sectional survey data of 285 households, in Ben Tre Province, Vietnam, to evaluate the effects of aquaculture involvement on poverty, measured using per capita consumption of less than $1.25 USD, $1.50, and $2.00 per day. The results show for per capita consumption of less than $1.25 per day that households’ aquaculture participation or productivity had no or little effect on the living standard. For income levels above $1.25 per capita per day aquaculture participation or productivity influenced the standard of living.     

INLAND AQUACULTURE IN INDIA: PAST TREND,PRESENT STATUS AND FUTURE PROSPECTS

ABSTRACT

In India, inland aquaculture has emerged as a fast-growing enterprise and a viable alternative to the declining capture fisheries. The present paper is an attempt to assess Indian inland aquaculture with respect to its resource base, output trends, systems and activities, yield gaps, adoption and impact on aquaculturists, economics, returns to inputs, investment needs, and future prospects. The paper is largely based on existing literature and observations made as part of an ICAR-WorldFish demand supply project. Indian aquaculture is primarily limited to inland sector and carp-oriented; for that reason, this activity received special attention. Freshwater aquaculture observed tremendous growth in the past 15 years, but immense scope still exists for horizontal expansion and increases in productivity (vertical expansion). This is evidenced by the fact that the average farm fish yield is only one-third of that achieved in farm trials. The difference was mainly due to much higher input use in on-farm trials. Most of the aquaculturists were practicing extensive aquaculture, but aquaculturists with semi-intensive operations benefited most from adoption of technology. The benefit:cost ratios for different systems of aquaculture varied between 1.22 to 1.86. The return to capital was much higher than the return to labor, due to the low labor input. The semi-intensive aquaculture system would receive the greatest return from projected macrolevel investments, followed by extensive and intensive systems. Dedicated efforts are needed to meet the demand for quality fish seed and feed in order to achieve the desired 45% increase in area and greater than 50% increase in productivity. Based on the observations, activities designed to foster inland aquacultural development in India are recommended.