Towards environmentally sustainable aquaculture: Comparison between two trout farming systems using Life Cycle Assessment

Life Cycle Assessment (LCA) was applied to evaluate the global environmental impact of two scenarios of trout production systems based on the operational information from an operational farm using a flow through system (FTF) and an experimental pilot low head recirculating system (RSF) located on the same site. The main differences between the environmental balances of the two systems were relative to water use, eutrophication potential and energy use. Independently of the system used, feed is the key indicator in determining the environmental balance (notwithstanding eutrophication potential and water dependence) monitored by fish production, chemical products, buildings and energy consumption.Consequently, when considering the RSF with a lower feed conversion ratio (0.8 versus 1.1 for FTF), the environmental balance of the RSF is more favourable at both global and regional levels, except with regards to energy use. RSF water dependence is 93% lower than the FTF and its eutrophication potential is 26–38% lower due to reduced waste release. On the other hand, at 57,659 MJ per ton of fish produced (16 kWh per kg), the RSF consumes 24–40% more energy than the FTF, especially for aeration and water treatment. Nevertheless, the RSF has significant potential for energy reduction through improvements to airlift and biofilter designs which would reduce RSF energy use to a level similar to that of the FTF (34,869–43,841 MJ per ton of fish produced, corresponding to 10 and 12 kWh respectively). LCA is therefore a powerful tool which can be used on fish farms to define and prioritise the most promising potential improvements to the system.     

Economic feasibility of recirculating aquaculture systems in pangasius farming

This study aims to analyze the economic feasibility of recirculating aquaculture systems (RAS) in pangasius farming in Vietnam. The study uses a capital budgeting approach and accounts for uncertainty in key parameters. Stochastic simulation is used to simulate the economic performance of medium and large farms operating with a traditional system or RAS. Data are obtained through structured surveys and a workshop in the Mekong River Delta. Results show that for large farms, net present value increases from an average of 589,000 USD/ha to 916,000 USD/ha after implementing RAS. Overall, the probability that RAS is a profitable investment is found to be 99% for both farm sizes. With RAS, the crucial parameters determining profitability are price, yield, costs of fingerling, feed, and initial investment. Findings on the robustness of the economic performance of RAS are useful to support public and private decision making towards increasing the sustainability of pangasius production.     

Research with a farming systems perspective needed for the development of small-scale aquaculture in non-industrialized countries

The global rise in the production of farmed fish and shellfish in non-industrialized countries has been supported by aquaculture research aiming most often to solve problems for factory-like production of highly valued aquatic species. It can be observed however, that research at the small-scale aquafarmers' level is lagging behind. Research with the holistic farming systems perspective and farmers' participation offers a chance to support aquaculture production at the small-scale farmers' level in non-industrialized countries.     

水产养殖业可持续发展及管理的研究进展

全球水产养殖业在过去的几十年内得到了迅速发展,但同时也带来了诸多的环境、经济和社会问题,因此可持续发展水产养殖理念的提出得到了国内外众多学者的认可。本文简单介绍了全球水产养殖业近年的发展情况及可持续发展水产养殖业的理念发展进程,重点分析了可持续发展水产养殖管理涉及的六大步骤,介绍了水产养殖指标体系构建及评估的研究成果,以期为我国水产养殖可持续发展提供借鉴。     

健康养虾模式在可持续发展中的作用

我国的对虾养殖业在经历了1982-1992年的快速发展阶段和1993-1994年的急剧衰退阶段之后,在各级政府和有关科研、生产部门的协同努力下,近年来开始复苏.这一发展--衰退--复苏的过程,体现了人类在改造自然中不断认识不断实践不断提高的过程,这将有助于对虾养殖业在今后的发展中更好地遵循自然规律,在谋求生产发展的同时,通过各种途径解决矛盾,减少病害,达到持续发展的目的.本文旨在通过对我国对虾养殖模式演变规律的回顾,探讨其在健康养殖中的作用.     

水产养殖业可持续发展及管理的研究进展

水产养殖装备是高效发展现代水产养殖,促进水产养殖产业结构改革的重要技术支撑。基于养殖装备、信息技术和自动控制等多学科协同发力的智慧水产养殖模式已成为现代渔业高质量发展的新趋势与重要抓手,这也对水产养殖现有装备及其相关技术提出了更高的智能化要求。本文梳理了池塘、工厂化、网箱、筏式和底播养殖等5种主要养殖方式装备发展现状,从数字化和智能化角度分析了环境监测、对象感知、饲料投喂、分级计数等养殖环节中常用装备的研究进展,指出了制约我国水产养殖智能装备与技术发展的关键问题,提出了“机械化、自动化、智能化”的水产养殖装备与技术发展的新思路,旨在实现我国从水产养殖大国向水产养殖强国的历史转变。

     

白洋淀水产养殖污染分析及可持续发展建议

阐述了白洋淀水产养殖对水体造成的污染。其中,饵料的投放、添加剂和药剂的使用、鱼类的排泄以及底质释放等是造成水体中氮、磷含量偏高及水体富营养化的主要原因。本文就水产养殖对水体及周边生态环境的影响和渔业生产存在的问题作了综述,从发展健康养殖和改善管理水平方面,提出了白洋淀水产养殖可持续发展的对策。     

辽宁海水养殖业发展现状及可持续发展对策

辽宁海水养殖业在全国具有重要地位.随着城市化、工业化进程推进,多元用海矛盾问题凸显,养殖空间萎缩,受技术、管理等因素制约海域资源利用效率不高,养殖生产方式传统粗放,近岸环境监控压力增大,水产品质量存在安全隐患.解决这些问题需要合理规划布局,优化海域空间资源配置,加强技术创新,改变传统生产方式,提高病害防控能力,保护海域生态环境,提高养殖产品质量.     

系统功能视角下的水产养殖业可持续发展

水产养殖系统具有食物生产、价值增殖和环境维持三大基本功能.目前,国际和国内水产养殖业在功能实现上存在着食物生产功能的弱化、价值增殖功能遇到阻力、环境维持功能遭遇挑战等问题.水产养殖业可持续发展就是要平衡水产养殖系统的基本功能,实现综合效益的最大化,关键是要解决"粮食"生产与价值增殖、环境保护与价值增殖的矛盾.中国水产养殖产业肩负着保障未来全国16亿人口食物安全的重任,即食物生产的任务,同时,该产业的发展还要遵循市场经济规律.因此,水产养殖业的发展离不开政府的引导和支持.     

Towards sustainable freshwater prawn aquaculture – lessons from shrimp farming, with special reference to India

The annual increase in farmed freshwater prawn production in the world during the decade ending 2001 has been estimated as 29% and that during 1999–2001 as 48%, the production in 2001 being about 300 000 mt (all Macrobrachium species). Between 1999 and 2003 the annual increase in farmed Macrobrachium rosenbergii production in India was about 80%, production reaching 30 450 mt in 2002–2003. This log phase of production followed the rise and fall of shrimp farming in the country. Several shrimp farming ventures collapsed in the 1990s, owing to degraded environment and diseases, abetted by lack of awareness and inadequacy of information on the culture systems and their interactions with other human endeavours. This shrimp farming experience has made the aquafarmer and other stakeholders aware that while aquaculture has a high potential in ensuring food and nutritional security and livelihood, besides profit to the farmer and socio‐economic benefits to local communities, it is likely to slip from sustainable development pathways if adequate understanding, improved management practices, governmental policies and plans for implementation and regulation to ensure sustainability are not in place. The lessons learned from shrimp farming can help in steering the development of sustainable freshwater prawn aquaculture in India and elsewhere.     

Safety issues and sustainable development of European aquaculture: new tools for environmentally sound aquaculture

Sustainable and long-term growth of the aquaculture industry should involve both ecologically sound practices and appropriate resource management. The increasing economic dimension of Mediterranean aquaculture is opening new economic niches and may be a valid support to reduce the pressure of traditional fisheries. Aquaculture practices can also lead to modifications of coastal habitats through the impact of wastes of land-based and open-sea mariculture facilities. In addition to these aspects which place a direct pressure on aquatic ecosystems and wild fishery resources, a wide range of environmental contaminants, such as chemicals used in farming operations, can accumulate in farmed organisms and put fish health and quality at risk. Thus, as aquaculture makes its transition to a major food-producing sector, proper assessment and control of environmental impacts and food safety awareness are becoming increasingly important. The development of simple tools able to monitor the extent of environmental and biological impacts associated with farming operations at various levels of biological complexity from the ecosystem to the organism level is required. Although a number of techniques for assessing the environmental and biological impact of pollutants in natural ecosystems are available, the development of practical and validated tools is sorely needed in aquaculture.     

The economics of sutchi catfish (Pangasianodon hypophthalmus) aquaculture under three different farming systems in rural Bangladesh

This paper examines production costs and returns of sutchi catfish (Pangasianodon hypophthalmus) aquaculture under three different farming systems in Bangladesh. Based on the production technology, sutchi catfish farming is classified as extensive, semi‐intensive and intensive. Results showed that sutchi catfish farming is profitable irrespective of the level of intensification and in all three instances the cost of feed dominated the variable costs of production. The average annual production costs were estimated at US$5217 ha^?1 in intensive farming, while US$2694 ha^?1 in semi‐intensive and US$981 ha^?1 in extensive farming. Despite the higher production costs per hectare, the average annual net return was higher in intensive farming (US$3364), compared with semi‐intensive (US$2048) and extensive (US$1099) farming. The average annual production per hectare under intensive farming conditions (13 945 kg) was higher than semi‐intensive (7705 kg) and extensive (3380 kg) farming mainly due to higher levels of inputs, including seed, feed, fertilizer and labour. However, the Cobb–Douglas production function model suggests that inputs are inefficiently used in the intensive farming system. Conversely, there is enough scope to increase the production and income from the semi‐intensive and extensive farming systems by using more inputs.     

Shrimp farming in Latin America: Current status,opportunities, challenges and strategies for sustainable development

Abstract

Shrimp farming in Latin America and the Caribbean (hereinafter, LA&C) is a complex, diverse and dynamic activity, occurring in 22 out of 36 countries, producing 231,000 tons, valued at US$ 1.2 billion in 2002¹. Farmed shrimp represents 52% of all shrimp volumes produced regionally, and almost 18% of all shrimp and prawn (S&P, hereinafter) cultivated worldwide. Whiteleg shrimp (Litopenaeus vannamei) constitutes 91% of all shrimp farmed in LA&C and five nations, led by Brazil ‐formerly by Ecuador‐, comprise 82% of farmed production. Over 90% of LA&C shrimp production is exported (230,000 tons of end products from both aquaculture and wild origin valued at US$ 1.36 billion), generating a trade surplus of US$ 1.28 billion (2002).

Farmed shrimp could easily surpass 513,000 tons by 2030, more than doubling current regional figures (2.9% annual growth rate, compounded). However, competition with Asian countries, anti‐dumping accusations and other factors might limit the expansion process, which is increasingly determined by strategically important matters rather than by physical production constraints. Here, a ‘production‐driven’ process of past decades is being replaced by a ‘demand‐led’ situation, where market and marketing issues will increasingly influence the outcome of shrimp farming.

Growing market competition will continue to press prices down and industry will be forced into a permanent process to improve competitiveness. Here, development strategies include actions by governments and producer associations, promotional and marketing campaigns and the application of good management practices across the production and distribution chains.     

Cage culture development and its role in aquaculture in China

Abstract. This paper is divided into four parts. First, history: cage culture has long been practised. The origin of cage culture world-wide should be regarded as the middle reaches of the Yangtze River, China, in the Sung Dynasty. Second, characteristics of cage culture in China. Third, influence: development of open-water fisheries is actively promoted in lakes, reservoirs and rivers. More kinds of water bodies have been employed for this purpose. Marine cages have also rapidly developed. Finally, discussion and conclusions. Cage culture is a modern development of aquaculture which has changed the long-established, fish-farming structures and, to a great extent, pushed forward fisheries development in China. Cage culture is typically characterized by intensive farming, running-water culture, high yield and great efficiency. It is generally accepted that cage culture will actively play an increasingly important role in international aquaculture.     

云纹石斑鱼工厂化循环水养殖技术

本试验率先采用循环水系统开展了云纹石斑鱼的养殖试验并取得了成功.结果显示,在莱州明波养殖基地选用的平均体重50 g/尾规格的云纹石斑鱼苗种10万尾,在水温22～ 25℃、盐度28～31、pH7.8～ 8.2的水环境条件下,经12个月培育,长成平均体重为0.65 kg/尾的商品鱼,平均单尾月增重50 g,成活率93.5％;共收获成鱼9.35万尾,单产49.9 kg/m3.本研究为云纹石斑鱼工厂化循环水养殖提供一个成功的范例.     

DMTIOLA: decision making tool for identification of optimal location for aquaculture farming development

Decision making tool called Decision Making Tool for Identification of Optimal Location in Aqua farming development was developed using Visual Basic programming language for identification of optimal location for aquaculture farming development. Twenty-four input criteria to the tool were categorized into six broad heads of main-criteria namely: water (10 sub-criteria), soil (5 sub-criteria), support (2 sub-criteria), infrastructure (3 sub-criteria), input (1 sub-criterion), and risk factor (3 sub-criteria). In this tool, the optimal location was identified based on the objective function, which was derived from the combination of rank sum, pair-wise comparison, and Technique for Order Preference by Similarity to the Ideal Solution methods. Based on the objective function values, alternatives (or aqua farms) were ranked in descending order in a table. In order to validate the developed tool, the same alternatives were ranked in descending order according to the observed average yield value per hectare (ha) for the last three crops. Spearman’s rank correlation was used to assess the correlation between ranks obtained by the tool and ranks obtained based on average yield. It showed with 99% confidence that a significant correlation exists between ranks obtained by the tool and ranks obtained based on average yield. Developed tool appeared to be confident and robust in proof-of-concept application for aquaculture farming development in Kalla mandal with reference to shrimp farms, West Godavari district, Andhra Pradesh, India.     

中华绒螯蟹病害的流行态势及其对产业持续发展的思考

中华绒螯蟹(Eriocheir sinensis)养殖业是我国水产养殖支柱产业之一。随着中华绒螯蟹养殖产业飞速发展,病害问题也愈加严重,并逐渐成为了产业发展的"瓶颈"问题。本文就我国近年来中华绒螯蟹病害流行的态势、病害流行原因以及应对措施进行剖析,以期为推动该产业的持续发展提供相应的参考。     

Developing native fish species for aquaculture: the interacting demands of biodiversity, sustainable aquaculture and livelihoods

Aquaculture continues to be the fastest growing animal production industry and this rate of expansion must continue if aquaculture is to satisfy global demand for fish products in the face of dwindling capture fisheries. The relationship between aquaculture and biodiversity is complex, with examples of positive and negative impacts having been reported. To enable this expansion while avoiding negative impacts from introductions of exotic species, the investigation of indigenous species becomes important and worthwhile.This paper establishes the background to development of new species for culture and describes the example of the Mexican silverside Menidia estor, which has for centuries been the principal species in an artesanal fishery in Lake Pátzcuaro, Mexico. The species is geographically isolated and is unique but is now endangered because of a range of factors including overfishing, environmental degradation and introduction of exotic species. Considerable advances have been made recently in developing a closed reproductive cycle, understanding feeding and small‐scale on‐growing technology for the species. Based on this, a Darwin Initiative programme was developed focused on technology transfer to implement small‐scale pilot on‐growing thus helping to conserve the species and to improve livelihoods. This has allowed successful pilot scale development of aquaculture for the species while at the same time addressing the objectives of the international Convention on Biodiversity.     

我国渔用疫苗的研制

定量（quantitive PCR）是用PCR技术评估样本中靶基因的分子数，实现对核酸信息的量化分析及比较。目前主要有外标法和内标法两大类。其中，其中外标法中主要有PCR产物的直接定量法，极限稀释法等；内参标法中主要有竞争性和非竞争性PCR等。