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1.
Life cycle assessment (LCA), a tool used to assess the environmental impacts of products and processes, has been used to evaluate a range of aquaculture systems. Eighteen LCA studies were reviewed which included assessments of recirculating aquaculture systems (RAS), flow-through systems, net cages, and pond systems. This review considered the potential to mitigate environmental burdens with a movement from extensive to intensive aquaculture systems. Due to the diversity in study results, specific processes (feed, energy, and infrastructure) and specific impact categories (land use, water use, and eutrophication potential) were analyzed in-depth. The comparative analysis indicated there was a possible shift from local to global impacts with a progression from extensive to intensive systems, if mitigation strategies were not performed. The shift was partially due to increased electricity requirements but also varied with electricity source. The impacts from infrastructure were less than 13 % of the environmental impact and considered negligible. For feed, the environmental impacts were typically more dependent on feed conversion ratio (FCR) than the type of system. Feed also contributed to over 50 % of the impacts on land use, second only to energy carriers. The analysis of water use indicated intensive recirculating systems efficiently reduce water use as compared to extensive systems; however, at present, studies have only considered direct water use and future work is required that incorporates indirect and consumptive water use. Alternative aquaculture systems that can improve the total nutrient uptake and production yield per material and energy based input, thereby reducing the overall emissions per unit of feed, should be further investigated to optimize the overall of aquaculture systems, considering both global and local environmental impacts. While LCA can be a valuable tool to evaluate trade-offs in system designs, the results are often location and species specific. Therefore, it is critical to consider both of these criteria in conjunction with LCA results when developing aquaculture systems. 相似文献
2.
Asian carp farming systems: towards a typology and increased resource use efficiency 总被引：1，自引：0，他引：1
Resource use efficiency in Asian carp farming systems is analysed based on a survey of 2493 farms of nine countries. Multivariate classification of farms by intensity and diversity identified six farm types: four types of specialized aquaculture farms at different levels of intensity, and two types of integrated agriculture–aquaculture systems. Pond‐based, specialized semi‐extensive systems (using mainly inorganic fertilizers and feeds of off‐farm origin), and integrated semi‐intensive systems (using feeds and fertilizer of both on and off‐farm origin) are by far the most common types, accounting for 59% and 27% of all farms respectively. Specialized semi‐extensive systems also show the highest protein and nutrient (N and P) use efficiencies, and among the highest labour use efficiency. Super‐intensive cage farms are less efficient in nutrient and labour use, but provide very high returns to land and capital investment. On average, the aquaculture components of integrated agriculture– aquaculture systems are less nutrient, land, and labour efficient than specialized semi‐extensive systems. Integrated semi‐extensive systems (using organic fertilizers of on‐farm origin) are particularly inefficient across all indicators. Hence in practice, gains in overall resource use efficiency through on‐farm integration with agricultural production are constrained by the relative inefficiency of the aquaculture subsystems on integrated farms. Although such systems can likely be improved, integration as such is not a panacea to increasing resource use efficiency. Wide variation in resource use efficiency within all systems indicates potential for substantial efficiency gains through improved management regardless of the fundamental choice of system. 相似文献
3.
Claude E. Boyd Louis R. D'Abramo Brent D. Glencross David C. Huyben Lorenzo M. Juarez George S. Lockwood Aaron A. McNevin Albert G. J. Tacon Fabrice Teletchea Joseph R. Tomasso Jr Craig S. Tucker Wagner C. Valenti 《Journal of the World Aquaculture Society》2020,51(3):578-633
Important operational changes that have gradually been assimilated and new approaches that are developing as part of the movement toward sustainable intensive aquaculture production systems are presented via historical, current, and future perspectives. Improved environmental and economic sustainability based on increased efficiency of production continues to be realized. As a result, aquaculture continues to reduce its carbon footprint through reduced greenhouse gas emissions. Reduced use of freshwater and land resources per unit of production, improved feed management practices as well as increased knowledge of nutrient requirements, effective feed ingredients and additives, domestication of species, and new farming practices are now being applied or evaluated. Successful expansion into culture of marine species, both off and on shore, offers the potential of substantial increases in sustainable intensive aquaculture production combined with integrative efforts to increase efficiency will principally contribute to satisfying the increasing global demand for protein and food security needs. 相似文献
4.
Ecology of Blue-Green Algae in Aquaculture Ponds 总被引：5，自引：0，他引：5
Cyanobacteria (blue-green algae) in the genera Anabaena, Aphanizomenon, Microcystis, and Oscillatoria often form extensive and persistent blooms in freshwater aquaculture ponds. Bloom-forming cyanobacteria are undesirable in aquaculture ponds because: 1) they are a relatively poor base for aquatic food chains; 2) they are poor oxygenators of the water and have undesirable growth habits; 3) some species produce odorous metabolites that impart undesirable flavors to the cultured animal; and 4) some species may produce compounds that are toxic to aquatic animals. Development of cyanobacterial blooms is favored under conditions of high nutrient loading rates (particularly if the availability of nitrogen is limited relative to phosphorus), low rates of vertical mixing, and warm water temperatures. Under those conditions, dominance of phytoplankton communities by cyanobacteria is the result of certain unique physiological attributes (in particular, N2 fixation and buoyancy regulation) that allow cyanobacteria to compete effectively with other phytoplankton. The ability to fix N2 provides a competitive advantage under severe nitrogen limitation because it allows certain cyanobacterial species to make use of a source of nitrogen unavailable to other phytoplankton. The ability to regulate cell buoyancy through environmentally-controlled collapse ad reformation of intracellular gas vacuoles is perhaps the primary reason for the frequent dominance of aquaculture pond phytoplankton communities by cyanobacteria. Cyanobacteria that can regulate their position in the water column gain a distinct advantage over other phototrophs in poorly mixed bodies of water. In addition to the physicochemical interactions that influence phytoplankton community dynamics, cyanobacterial-microbial associations may play an important regulatory role in determining community structure. Cyanobacteria are always found in close association with a diverse array of microorganisms, including eubacteria, fungi, and protozoans. These associations, which in the past have often been viewed as antagonistic, are increasingly seen as mutualistic and may function in a positive manner during bloom development. 相似文献
5.
N. Papandroulakis M. Kentouri E. Maingot P. Divanach 《Aquaculture International》2004,12(4-5):345-355
Species diversification is today considered as a major issue for the sustainable development of the Mediterranean aquaculture. For successful propagation of any species however, larval rearing is considered a bottleneck and therefore the development of appropriate tools is essential. Mesocosm is a semi-intensive technology that facilitates larval rearing of several species integrating principles of both intensive and extensive aquaculture, which solves biological problems and many of their technical, human and economical consequences. The extensive (and now even the semi-extensive) strategy is used in the most critical segments of the rearing process during the early developmental stages, when larvae are still extremely weak, sensitive to intensive environment, easily stressed and difficult to feed. The intensive strategy is used as soon as larvae are considered mature enough to be reared easily using classical methods. The technology was used for the rearing of two species, with potential for aquaculture, the sharpsnout seabream (Diplodus puntazzo) and the white seabream (Diplodus sargus sargus). Three groups of each species were monitored for a period of 50–70 days post hatching. Survival for both species was about 54% at the end of the trials. Sharpsnout seabream larvae reached 19.6 ± 0.9 mm total length and 107.2 ± 31.9 mg body weight 50 days post hatching. White seabream larvae 60 days post hatching reached 32.7 ± 2.7 mm total length and 450 ± 70 mg body weight. In order to verify the economical viability of the technology, the individual production cost for each species was estimated and reached ¢0.027 for white seabream and ¢0.043 for sharpsnout seabream. Results indicate the reliability of the technology for the larval rearing of the two species. 相似文献
6.
Roselien Crab Yoram Avnimelech Tom Defoirdt Peter Bossier Willy Verstraete 《Aquaculture (Amsterdam, Netherlands)》2007,270(1-4):1-14
As the aquaculture industry intensively develops, its environmental impact increases. Discharges from aquaculture deteriorate the receiving environment and the need for fishmeal and fish oil for fish feed production increases. Rotating biological contactors, trickling filters, bead filters and fluidized sand biofilters are conventionally used in intensive aquaculture systems to remove nitrogen from culture water. Besides these conventional water treatment systems, there are other possible modi operandi to recycle aquaculture water and simultaneously produce fish feed. These double-purpose techniques are the periphyton treatment technique, which is applicable to extensive systems, and the proteinaceous bio-flocs technology, which can be used in extensive as well as in intensive systems. In addition to maintenance of good water quality, both techniques provide an inexpensive feed source and a higher efficiency of nutrient conversion of feed. The bio-flocs technology has the advantage over the other techniques that it is relatively inexpensive; this makes it an economically viable approach for sustainable aquaculture. 相似文献
7.
Redclaw crayfish (Cherax quadricarinatus, von Martens 1868) is a freshwater decapod crustacean with a number of biological and commercial attributes that make it an excellent aquaculture species. The redclaw aquaculture industry has been growing rapidly since the mid‐1980s in tropical and subtropical regions of the world. Redclaw aquaculture is mostly in extensive pond systems, but interest in developing more intensive systems is increasing. To support continued intensification, development of high‐quality practical diet formulations and information about redclaw nutrition requirements are necessary. A number of studies have determined optimum dietary protein and lipid requirements for juvenile redclaw. However, there is limited information on essential amino acid and fatty acid requirements. Several studies report the presence of various digestive enzymes that have been linked to the ability of the species to digest a wide range of dietary components. Furthermore, as in many other aquaculture species, there is a need to replace fishmeal with other protein sources. A number of studies explored the possibility of replacing fish meal with various terrestrial plant sources of protein and lipids and showed that redclaw can be offered diets containing low‐cost, plant‐based ingredients without compromising survival, growth and, to a certain extent, reproduction. Formulated diets containing less expensive, plant ‐ based ingredients will contribute to a more profitable and environmentally sustainable redclaw aquaculture industry. Finally, there is also a paucity of information on vitamin and mineral requirements of redclaw and little information on nutrient requirements of broodstock. For the redclaw aquaculture industry to thrive, we need to have a better understanding of nutrient requirements at all life stages. 相似文献
8.
不同鲤养殖模式生物絮团系统中鱼体的生长及水质 总被引：2，自引：2，他引：0
为了探明不同鲤养殖模式生物絮团系统中鱼体的生长及水质变化情况。采用陆基围隔法,分别设置了鲤单养、鲤+鳙二元混养及鲤+鳙+鲢三元混养3种鲤养殖模式,每种模式设3个重复,测定了鲤不同养殖模式下鱼体的生长及水质参数,实验共进行90 d。结果显示,与单养模式相比,二元混养和三元混养鲤的存活率和鱼体蛋白质效率均显著偏高,而其总饲料系数则显著偏低。3种养殖模式中鲤肌肉的水分和粗脂肪含量相互之间差异均不显著,三元混养模式鲤肌肉的粗蛋白和灰分含量均显著高于单养模式。在3种养殖模式生物絮团系统中,生物絮团形成量与水温之间在19.3~28.5°C范围内呈显著的正相关。整个实验过程中,二元混养和三元混养水体的总氨氮、亚硝酸态氮、总无机氮、正磷酸盐及总悬浮颗粒物含量均低于单养模式,而硝酸态氮、总碱度、有机悬浮颗粒物及叶绿素a含量均高于单养模式,除叶绿素a之外,其余水质参数相互之间差异均不显著。研究表明,与传统的混养系统相似,在生物絮团养殖系统中,符合生物学原则的混养模式同样能够有效发挥养殖系统的生态功能,提高养殖效率。 相似文献
9.
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. 相似文献
10.
The production of rainbow trout (Oncorhynchus mykiss Walbaum 1792) is practiced in different production systems including extensive system (ES), intensive system (IS) and recirculating aquaculture systems (RAS). These production systems are different in their quantitative requirements of resource utilization and subsequent output and emissions that impact the environment. In this paper, consequential life cycle assessment (LCA) is used to analyze the environmental impact of rainbow trout production using these production systems in an attempt to determine the relative performances and identify options for future improvements. The life cycle impact assessment (LCIA) indicate that impact from four impact categories chosen, RAS showed the largest impact in global warming (GWP), acidification (AP) and land competition (LC), while its impact on eutrophication (EP) and water-use was the lowest relative to ES and IS. This signified that while RAS has the capability to reduce impacts in the EP category by avoiding water emissions, the increased use of energy for water filtration and reuse increases impact through global emissions. However, sensitivity analysis revealed that RAS has the potential to reduce the overall impact when using a marginal energy source based on wind power as compared to ES and IS. In conclusion, impacts which are specific to aquaculture need to be considered in LCA to draw comprehensive analysis of the impacts. In addition, identification of the underlying problems of the different impacts is important in finding solution leading to sustainability of aquaculture. 相似文献
11.
Odonate larvae are important components of aquatic environments in tropical areas. They also develop in aquaculture ponds, where they can cause economic losses. In this study, we have tried to describe the general community patterns in aquaculture ponds in Viçosa, south-eastern Brazil. Our aim is to evaluate how environmental and bionomic factors can determine their composition and species richness. We identified two groups of species (plants and bottom-dwellers) based on larval microhabitat preferences. Vegetation determines the occurrence of some species whose adults select certain plants for oviposition. The ponds with more extreme conditions (extensive cover of plants or vegetation absent) showed lower species richness than those with intermediate conditions. Coryphaeshna adnexa and Brachmesia furcata were of larger size but had low abundance or were only collected accidentally. Species of intermediate size (Tramea cophysa, Micrathyria spp., Orthemis discolor and Erytrodiplax fusca) were more abundant and are considered as potential predators of fish fry. 相似文献
12.
池塘养殖是我国海水养殖的传统方式，也是当前陆基海水养殖的主体。自20世纪70年代，海水池塘养殖经历了粗放式、半集约、集约化和多营养层次生态养殖的发展历程。然而，海水池塘养殖产业中仍存在养殖生物生态适应性机制不清、养殖系统产出不稳定、营养物质利用效率低等“瓶颈”问题，严重制约了海水池塘养殖产业的发展。因此开展海水养殖虾蟹良种与生态环境的互作机制解析，研发养殖生态系统结构优化和营养物质资源化高效利用技术，搭建养殖信息采集与智能化管控平台，创建生态工程化养殖新模式，实现养殖系统高效可持续产出，是我国海水池塘养殖产业绿色高质量发展的关键。 相似文献
13.
Robert Pomeroy Madan M. Dey Nataliya Plesha 《Aquaculture Economics & Management (Blackwell Science)》2013,17(3):303-324
As a result of the concern and debate about the impacts of intensive aquaculture development on biodiversity, semi-intensive aquaculture is being considered as an alternative. Although the biophysical impacts of aquaculture on biodiversity have been examined, there is only limited understanding of the social and economic impacts of aquaculture on biodiversity, and especially the impacts of the shift from intensive to semi-intensive systems. The purposes of this article are twofold: (1) to identify and discuss the social and economic impacts of aquaculture on biodiversity, and (2) to examine the impacts while moving from intensive to semi-intensive systems. After discussing the findings of our study, we provide some recommendations as to how to minimize social and economic impacts of aquaculture on biodiversity by moving to a lower intensity aquaculture system. The integrated agriculture-aquaculture farming systems, stakeholder involvement in management, and well defined basic rights are aquaculture systems that contribute to conservation of biodiversity. 相似文献
14.
Viral haemorrhagic septicaemia (VHS) is a well-characterized disease of rainbow trout, Oncorhynchus mykiss, which has also caused economic losses in marine turbot farms in the British Isles. We have previously demonstrated that turbot, Scophthalmus maximus, are susceptible to isolates of viral haemorrhagic septicaemia virus (VHSV) that are endemic in the marine environment, highlighting a potential risk to marine aquaculture. Given the increasing interest in the intensive rearing of additional aquaculture species such as Atlantic cod, Gadus morhua, and Atlantic halibut, Hippoglossus hippoglossus, this study aimed at investigating the susceptibility of these species to VHSV. Both species were found to be largely resistant to VHS following immersion challenge with a selection of 18 isolates, representing the known marine VHSV genotypes. Only one and two VHSV-associated mortalities occurred out of a total of 1710 and 1254 halibut and cod, respectively. These findings suggest that there is a low direct risk to the development of commercial cod and halibut aquaculture from the existing endemic reservoir of VHSV. This study, coupled to field observations has, however, highlighted the fact that both species can become infected with VHSV. The known adaptability of RNA viruses, together with the selection pressures associated with intensive aquaculture would thus advocate a cautious approach to VHSV surveillance within these emerging industries. 相似文献
15.
Aquaculture is a globally important industry that provides essential food to a growing world population, with a major role in the supply of cheap animal protein. Very rapid developments have been occurred in aquaculture sector of Egypt in recent years and exhibited the strongest growth of any fisheries-related activity in the country. As a result, aquaculture is considered as the only viable option for reducing the current gap between production and consumption of fish in Egypt. The rapid expansion in support activities such as local feed mills and hatcheries made the sector more sophisticated and diverse. Globally, Egypt ranks 9th in fish farming production and 1st among African countries. The aquaculture is practiced in different production systems including semi-intensive, intensive culture in ponds, tanks, intensive production in cages and traditional extensive production systems, but has yet to be adequately documented. Despite the fact that the aquaculture sector in Egypt has witnessed a spectacular development, it has also created challenges with respect to environmental issues and sustainability. This review provides an overview of the status and the perspectives of Egyptian aquaculture sector. 相似文献
16.
Since 1989, and in comparison to the global trend, inland aquaculture production of European finfish has declined. To date,
the yearly European freshwater aquaculture production is 371,727 tons, valued at over US$1 billion. Indigenous species accounted
for less than one-third of the production, whereas alien species (a species that has been moved beyond its natural range of
distribution) accounts for the remainder. However, in general, indigenous species command a higher market price. Currently,
food quality and food safety are leading concerns of consumers, and European consumers are also becoming alert to environmentally
detrimental practices. Therefore, to aim at economic sustainability, the sector needs to satisfy consumer expectations of
environmentally friendly practices. It is believed that farming alien finfish species can threaten local biodiversity through
escapes, and this represents a current environmental concern relative to aquaculture. In this context, an attempt is made
in this paper to understand and quantify the impacts of alien finfish cultivation in European inland waters, and to suggest
remedial measures. 相似文献
17.
Kwamena Quagrainie Steven Hart Paul Brown 《Aquaculture Economics & Management (Blackwell Science)》2013,17(1):54-70
Many Indiana small- and medium-sized farm and ranch operators are looking at aquaculture to diversify their operations, but the underlying thought for most of these potential aquaculturists is the feasibility of raising fish, and whether consumers will be interested in Indiana aquaculture products. The study used an ordered probit model to examine Indiana consumers' interests in Indiana farm-raised aquaculture products. The model did not predict any non-interest but predicted 18% probability of consumers that are somewhat interested, 58% for consumers that are interested and 24% for consumers that are strongly interested. Factors that positively affected interest in Indiana aquaculture products were previous purchase of farm-raised aquaculture products, frequent at-home seafood consumption—once per week, and being at least 36 years of age. While consumers in the household income $20,000–$59,999 group showed interest, households with higher incomes were less interested. Prices that consumers are willing to pay for Indiana seafood products are within the range of market seafood prices in Indiana. However, consumers will not be interested in Indiana aquaculture products as premiums for the products increase. 相似文献
18.
The proximity of many Pacific countries to seafood markets in Asia, the high value of species associated with coral reefs, and the increased demand for marine aquarium species, has prompted many nations in the region to investigate opportunities for coastal aquaculture. There are, however, several constraints to consider throughout much of the Pacific, including, transport problems, fragile ecosystems, lack of suitable sites, limited economies, and the effects of customary marine tenure on access to growout sites. To overcome these problems, coastal aquaculture in the Pacific will need to focus either on species of high value, or those that yield non-perishable products. Valuable industries have been established for pearl oysters, penaeid shrimps, and the microalgae, Spirulina, in tropical Australia, the French territories and Hawaii, whereas enterprises for cultured giant clams, milkfish (Chanos chanos) as tuna bait, the macroalgae, Eucheuma, and sponges are emerging in the small island developing states. Species demanded by the aquarium trade, groupers for live reef fish markets, tropical abalone (Haliotidae), mangrove crabs (Scylla spp.) and a variety of invertebrates as sources of bioactive compounds are promising new species for intensive farming. Aquaculture technology is being applied to the restocking and stock enhancement of valuable, sedentary species low in the food chain, and there are active programmes in several small island developing states to assess the scope for releasing cultured giant clams, trochus, green snail and sea cucumbers to replenish and enhance wild stocks. There is a growing awareness that the potential benefits of increased aquaculture, restocking and stock enhancement need to be balanced by the risks associated with culturing additional species, i.e. introduction of diseases, dilution of gene pools and increased biological interactions with other species, and that sustainable aquaculture, restocking and stock enhancement are most likely to be achieved with responsible application of technology and the use of indigenous species. 相似文献
19.
Khem R. Sharma Pingsun Leung 《Aquaculture Economics & Management (Blackwell Science)》2013,17(3):129-140
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. 相似文献
20.
Bio-filters: The need for an new comprehensive approach 总被引：8，自引：0，他引：8
The aquaculture industry struggles to profit in light of low product prices, increasing costs of inputs and constrains due to environmental, water and land limitations.
Intensive aquaculture systems are relevant to efficiently produce fish and shrimp. The two important limiting factors of intensive aquaculture systems are water quality and economy. An intrinsic problem of these systems is the rapid accumulation of feed residues, organic matter and toxic inorganic nitrogen species. This cannot be avoided, since fish assimilate only 20–30% of feed nutrients. The rest is excreted and typically accumulates in the water. Often, the culture water is recycled through a series of special devices (mostly biofilters of different types), investing energy and maintenance to degrade the residues. The result is that adding to the expenses of purchasing feed, significant additional expenses are devoted to degrade and remove 2/3 of it.
There is a vital need to change this vicious cycle. One example of an alternative approach is active suspension ponds (ASP), where the water treatment is based upon developing and controlling heterotrophic bacteria within the culture component. Feed nutrients are recycled, doubling the utilization of protein and raising feed utilization. Other alternatives, mostly based upon the operation of a water treatment/feed recycling component within the culture unit are discussed.
The present paper was presented in the biofilter workshop held in Honolulu, 8–11 November 2004. The main purpose of this paper was to raise new ideas and new options toward the planning and operation of intensive fish/shrimp ponds. 相似文献