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1.
Nguyen Minh Duc 《Aquaculture International》2009,17(1):15-29
Rural aquaculture is the farming of aquatic organisms with extensive and semi-intensive husbandry practised by small-scale
rural households for their consumption and income. From a field survey in Southeast Vietnam, using enterprise budget analysis
and nonparametric tests with indices of change, adoption, and agreement, this study justifies that rural aquaculture is a
good option for rural development, making an important contribution to farm income with a high adoption rate among poor farmers.
Fish farmers have gained an increased level of satisfaction by means of fish culture production growth along with corresponding
economic gains. This enterprise continues to play an increasing important role in their livelihoods and has potential to develop
further in the area. 相似文献
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Erika M. Plisetskaya 《Fish physiology and biochemistry》1989,7(1-6):39-48
From the very beginning of physiological studies on the endocine pancreas, fish have been used as experimental subjects. Fish
insulin was one of the first vertebrate insulins isolated and one of the first insulins whose primary and then tertiary structures
were reported. Before a second pancreatic hormone, glucagon, was characterized, a physiologically active ‘impurity’, similar
to that in mammalian insulin preparations, was found in fish insulins.
Fish have become the most widely used model for studies of biosynthesis and processing of the pancreatic hormones. It seems
inconceivable, therefore, that until the recent past cod and tuna insulins have been the only purified piscine islet hormones
available for physiological experiments. The situation has changed remarkably during the last decade.
In this review the contemporary status of physiological studies on the fish pancreas is outlined with an emphasis on the following
topics: 1) contents of pancreatic peptides in plasma and in islet tissue; 2) actions of piscine pancreatic hormones in fish;
3) specific metabolic consequences of an acute insufficiency of pancreatic peptides; 4) functional interrelations among pancreatic
peptides which differ from those of mammals. The pitfalls, lacunae and the perspectives of contemporary physiological studies
on fish endocrine pancreas are outlined. 相似文献
4.
The technology diffusion process of green mussel, Perna viridis, farming in Kerala, India, was studied by analyzing the adoption pattern, socioeconomic profile of mussel farmers, differences in farming methods, profit variations, development of trade and downstream industries, and the social factors responsible for the growth of this new industry. The farming practice has been adopted by villagers from 1996, and because of its rapid growth, India has risen to one among the top 10 farmed mussel producing nations in Asia, with an annual production of 10,060 tonnes, worth $US1.79 million at farm‐gate level. Three types of farm ownerships were observed: individual ownership (IND), family ownership (FAM), and ownerships by self‐help groups (SHG). The adoption curves are such that there were only a few adopters initially followed by an increasing rate of adoption in the subsequent years because of the demonstration effect. The study indicated the deep‐rooted “risk aversion” attitude widely prevalent among technology adopters. Age could not be significantly related to technology adoption, while education and occupation of the respondents significantly (P < 0.05) influenced the technology adoption process. The biggest outcome of mussel farming in Kerala was the empowerment of women with 87% of the SHG farms owned by women. The successful diffusion of mussel farming is the result of a combination of factors, chiefly, the availability of suitable water bodies; high rate of education; proximity of mussel markets and high degree of mussel consumption in the area; and a unique synergy between technology developers, promoters, and credit advancers. This development scenario can work as a role model for developing nations. 相似文献
5.
Epitheliocystis is a condition affecting the gills and skin of fish, which has been reported from more than 50 freshwater and marine species. It is caused by intracellular Gram-negative bacteria. Mortalities have been associated with epitheliocystis infections in cultured fish. This review provides an update of our current understanding of this condition, including characterization of the pathogen using immunohistochemical and molecular studies. In most fish species the epitheliocystis agent was negative to an antibody specific for chlamydial genus-specific lipopolysaccharide antigen. Recently, four epitheliocystis agents from four different fish species have been characterized using molecular analysis. While they all belong to the order Chlamydiales, in a lineage separate from the Chlamydiaceae, they are distinct organisms and similarity analysis showed that they had highest similarity values with other chlamydia-like bacteria isolated from various sources, including humans or pig. This confirms the high diversity and host specificity of the pathogen. Further molecular analysis should result in an increased understanding of this condition. To date the pathogen has not been cultured, making experimental studies difficult. High stocking densities, presence of nutrients, season, temperature and fish age have been identified as potential risk factors for the manifestation of this condition. 相似文献
6.
Fishways and other passage facilities frequently prevent or delay the passage of fishes, highlighting the need for effectiveness monitoring. We reviewed the scientific literature from 1960 to 2008 reporting on effectiveness monitoring of fish passage facilities to assess what taxa and life-stages have been studied, the questions that are asked during evaluation, and how these varied over time or by geographic region. We identified 96 peer-reviewed articles of which 68% focused on passage by adult fishes. Salmoniformes was the most studied order (58% of studies). The focus of fishway evaluations did not change over the years, but varied significantly by geographic region. Studies from the tropics had a broader taxonomic scope than studies from temperate locations. Exogenous mechanisms of passage failure, such as environmental, structural and behavioural factors, were studied in 90% of studies from North America but only ∼50% of studies from Europe, South America and Australia. Endogenous (i.e. physiological) mechanisms affecting passage success were not often assessed anywhere, though they were a powerful means of evaluating mechanisms of failure. Few studies monitored migration after fish had left a facility. To improve effectiveness monitoring of passage facilities, we suggest that both endogenous and exogenous mechanisms need to be studied in an integrated fashion to understand passage failure and to inform design or operational changes that could improve passage efficiency. In addition post-departure monitoring is required to more completely assess the fitness consequences of passage. 相似文献
7.
Compensatory density dependence in fish populations: importance, controversy, understanding and prognosis 总被引：12，自引：0，他引：12
Kenneth A Rose James H Cowan Jr Kirk O Winemiller Ransom A Myers & Ray Hilborn 《Fish and Fisheries》2001,2(4):293-327
Density‐dependent processes such as growth, survival, reproduction and movement are compensatory if their rates change in response to variation in population density (or numbers) such that they result in a slowed population growth rate at high densities and promote a numerical increase of the population at low densities. Compensatory density dependence is important to fisheries management because it operates to offset the losses of individuals. While the concept of compensation is straightforward, it remains one of the most controversial issues in population dynamics. The difficulties arise when going from general concepts to specific populations. Compensation is usually quantified using some combination of spawner–recruit analysis, long‐term field monitoring or manipulative studies, and computer modelling. Problems arise because there are limitations to each of these approaches, and these limitations generally originate from the high uncertainty associated with field measurements. We offer a hierarchical approach to predicting and understanding compensation that ranges from the very general, using basic life‐history theory, to the highly site‐specific, using detailed population models. We analyse a spawner–recruit database to test the predictions about compensation and compensatory reserve that derive from a three‐endpoint life‐history framework designed for fish. We then summarise field examples of density dependence in specific processes. Selected long‐term field monitoring studies, manipulative studies and computer modelling examples are then highlighted that illustrate how density‐dependent processes led to compensatory responses at the population level. Some theoretical and empirical advances that offer hope for progress in the future on the compensation issue are discussed. We advocate an approach to compensation that involves process‐level understanding of the underlying mechanisms, life‐history theory, careful analysis of field data, and matrix and individual‐based modelling. There will always be debate if the quantification of compensation does not include some degree of understanding of the underlying mechanisms. 相似文献
8.
鱼油所含的不饱和脂肪酸既有助于脂的消化吸收、转运和形成,又是生物膜的重要结构物质.鲣鱼加工中产生大量的下脚料,如果用于提取鱼油,可以创造可观的经济效益.本文探讨了利用鲣鱼加工废弃物提取、精制、纯化鱼油的工艺条件,并且对从鲤鱼废弃物中提取鱼油并纯化出高不饱和脂肪酸的方法进行了研究,得到的鱼油中高不饱和脂肪酸占24%,其中... 相似文献
9.
随着人口与经济的发展,水产养殖业在世界范围内迅速兴起,集约型工厂化循环水养殖因其高密度、低污染、高效率等独特的优势,契合水产养殖业绿色发展理念,已成为水产养殖转型升级的重要方向之一。水作为循环水养殖系统中重要的环境因子,其流态能够直接影响鱼类的生长及福利,同样,鱼类存在及运动也会影响到系统流态的构建。本文综合分析了循环水养殖系统中流场条件对不同鱼类生长发育及福利的影响,鱼类及其运动行为对养殖池内水动力条件及性能的影响,以及鱼类对养殖池内流场流态、水体混合等的影响。将研究鱼类运动对流场特性的影响方法主要归纳为实测法和数值研究,通过对比分析2种方法的优点和不足之处,并结合当前循环水养殖产业系统构建中的问题提出针对性方法建议,旨在为系统中水动力条件的设计拓展思路,促进循环水养殖产业流态构建向“鱼”与“水”兼顾的方向发展。 相似文献
10.
Adoption of the ecosystem approach to fisheries management relies on recognition of the link between fish and other components of the ecosystem, namely their physical and biological habitat. However, identifying the habitat requirements of marine fishes and hence determining their distribution in space and time is scientifically complex. We analysed the methodologies and findings of research on temperate, demersal fish habitat requirements to highlight the main developments in this field and to identify potential shortfalls. Many studies were undertaken over large spatial scales (≥100s km2) and these generally correlated abundances of fish to abiotic variables. Biological variables were accounted for less often. Small spatial scale (≤m2), experimental studies were comparatively sparse and commonly focused on biotic variables. Whilst the number of studies focusing on abiotic variables increased with increasing spatial scale, the proportion of studies finding significant relationships between habitat and fish distribution remained constant. This mismatch indicates there is no justification for the tendency to analyse abiotic habitat variables at large spatial scales. Innovative modelling techniques and habitat mapping technologies are developing rapidly, providing new insights at the larger spatial scales. However, there is a clear need for a reduction in study scale, or increase in resolution additional to the integration of biotic variables. We argue that development of sound predictive science in the field of demersal fish habitat determination is reliant on a change in focus along these lines. This is especially important if spatial management strategies, such as Marine Protected Areas (MPA) or No Take Zones (NTZ), are to be used in future ecosystem‐based approaches to fisheries management. 相似文献
11.
近年,鱼类生物能量学方面的研究空前活跃。一方面通过研究摄食水平、温度、盐度、体重等因素对鱼类生长的影响,建立能量收支方程和能量分配模型,为改革水产养殖生产工艺和调整管理技术提供有用的技术参数;另一方面,可以评估鱼类种群在整个生态系统中的作用。研究鱼类能量收支,建立能量分配模型,预测水域生产力,是水生生物研究中的热门课题之一。本文就鱼类生物能量学研究进展作扼要的概述。 相似文献
12.
利用26.7hm2池塘,通过接种单胞藻培养优势生物种群,使用有益微生物改良水质的方法,稳定和改善养殖生态环境,每hm2产海蜇6180kg、缢蛏5100kg、牙鲆360kg、对虾157.5kg,实现总产值416.7万元,利润252.8万元。 相似文献
13.
The physiology of triploid fish: current knowledge and comparisons with diploid fish 总被引：1，自引：0，他引：1
Valérie Maxime 《Fish and Fisheries》2008,9(1):67-78
This paper is aimed at underlining the limited knowledge available about the physiology of triploid fishes compared with diploids. Whereas many aspects (induction, detection, growth, resistance to diseases, etc.) in the production and rearing of triploid fishes have widely been developed and described in the literature, other numerous questions of ecophysiology remain in abeyance, and the study of triploid cells physiology is still in its infancy. Triploid fishes can be considered as models worthwhile for physiological investigations not only for the economical stake in relation to the development of triploid fishes rearing, but also for the cytological and molecular features of their tissues and organs. The functional implications of these features have been poorly studied although they are potential areas of applied and/or fundamental studies. 相似文献
14.
鱼类利用碳水化合物的研究进展 总被引：6，自引：0，他引：6
鱼类对碳水化合物的消化和代谢能力较差,缺乏对血糖水平的调控能力。众多的研究资料表明,摄入高碳水化合物通常会导致鱼体出现持续的高血糖、肝肿大、肝糖原累积、生长率和饲料效率降低。影响鱼类利用饲料碳水化合物的因素很多,包括鱼的食性、生长发育、胰岛素水平、消化及代谢酶、能量代谢水平等内因以及碳水化合物的种类、含量、摄食频率、环境温度等外因。本文综述了该领域的研究进展,并从能量代谢的角度对影响鱼类利用碳水化合物的因素及其机制进行了探讨,认为鱼类对碳水化合物的利用能力差与其维持生命活动的能耗功率水平相对应:鱼类(尤其是肉食性鱼类)代谢率较低,而以葡萄糖为底物代谢供能速率较高,因此摄入大量碳水化合物后可能导致供能速率过剩,以血糖的形式在体内堆积,表现为持续的高血糖现象。碳水化合物类型、摄食频率及水温对鱼类利用碳水化合物的影响均可能与此相关。 相似文献
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The temporal dynamics of biotic communities have been widely examined by ecologists. However, systematic reviews on how habitat features, sampling and data evaluation influence temporal patterns are rather sporadic. Here, we reviewed 307 peer-reviewed scientific articles to characterize the methods and the approaches, as well as to identify the knowledge gaps in the assessment of the temporal dynamics of freshwater fish assemblages with special regard to their stability patterns. The number of publications increased exponentially over decades. We revealed a highly uneven distribution of the studies among continents and ecosystems with a dominant number of papers derived from North America and Europe, and from lotic systems, especially. We also found large variability among studies even within similar habitat types in the examined spatial and temporal scales, sampling methods used, examined assemblage attributes, potential stressors and data analyses. Several knowledge gaps, such as the limited number of large-scale studies, the insufficient knowledge on the long-term dynamics of early life history stages and on trait-based assemblage organization, were highlighted. For enabling meaningful comparisons of fish assemblage dynamics in space and time, further developments in standardization procedures are needed across sampling and data evaluation possibilities. Publicly accessible long-term data sets with more details on sampling and environmental parameters would also be critically important to determine the effect of a variety of factors on the stability vs. variability of fish assemblages. 相似文献
17.
鱼类关键生境研究进展 总被引：1，自引：0，他引：1
鱼类关键生境(EFH)是指鱼类产卵、繁殖、摄食或育成所必须依赖的水域或底质环境。该文对EFH的产生和由来、研究和应用、评估内容和识别方法等现状进行了全面回顾和总结,重点在介绍相关概念和进展,并针对我国海洋渔业科研和管理中过于强调区域重要性和种类经济价值、而忽略具体生境保护的现实,提出了相应的建议,以期为我国渔业的科学管理和及其可持续发展提供参考。 相似文献
18.
Fu Cheng Yi Lian-Chun Wu Wen-Pei Sun Chun-Xiao Liu Rui-Na Fu Shi-Jian 《Fish physiology and biochemistry》2021,47(5):1415-1427
Fish Physiology and Biochemistry - Almost all prey live in habitats with predators with different hunting modes; however, most studies on predation have investigated the effects of only one... 相似文献
19.
Size-dependent predation on marine fish larvae by Ctenophores, Scyphomedusae, and Planktivorous fish 总被引：3，自引：0，他引：3
Size-dependent predation rates on marine fish larvae by the ctenophore Mnemiopsis leidyi , scyphomedusa Chrysaora quinquecirrha , and planktivorous fish Anchoa mitchilli were estimated via experiments in 3.2 m3 me-socosms. Predation rates on larvae of the goby Gobio-soma bosci were estimated in relation to 1) length of larval prey, 2) presence or absence of alternative < 1 mm zooplankton prey, and 3) a predator-prey interaction between the scyphomedusa and ctenophore. The consumption rate of larvae by the three predators generally declined as larval length increased. The ctenophore ate fewer (1.0 d-1 per predator) larvae than did the medusa (7.8 d -1 per predator) or bay anchovy (4.0 d -1 per predator), but it consumed larvae in all size classes tested (3.0–9.5 mm SL). Predation by bay anchovy and the medusa was more size-dependent: 3.0–5.0 mm larvae were most vulnerable. Fewer larvae were eaten by the ctenophore and bay anchovy when zooplankton alternative prey was available, but predation on larvae by the medusa was not influenced by alternative zooplankton prey. Consumption rate of fish larvae by the medusa was reduced 20–25% when the ctenophore was present as its alternative prey. An encounter-rate model was developed and its parameters estimated from the experimental results. Model simulations indicated that the relationship between larval size and vulnerability is dependent on size, swimming speed, and behavior of both predators and larvae, and that bigger or faster-growing fish larvae are not always less vulnerable to predation. 相似文献
20.
Uttam K. Sarkar Lianthuamluaia Lianthuamluaia Debabrata Panda Suman Kumari Pranaya K. Parida Gunjan Karnatak Puthiyottil Mishal 《Fisheries Management and Ecology》2020,27(5):481-489
The present study investigates the success of stocking fingerlings of Indian major carps ‐Gibelion catla (Hamilton), Labeo rohita Hamilton and Cirrhinus mrigala Hamilton – to enhance fish yield in 58 small reservoirs in Odisha State, India. Fish stocking and yield data were collected from State Fisheries Department, Odisha. The relationships between area, stocking density and fish yield of different size groups of reservoirs were assessed using the Pearson correlation coefficient (r). Fish yield increased significantly (p < 0.05, t‐test) from 204 kg/ha/year in 2012–13 to 323 kg/ha/year in 2013–14 due to adoption of CBF. The corresponding per capita fish production increased from 398 kg fisher?1 year?1 to 702 kg fisher?1 year?1 benefitting more than 8,000 fisher households. Reservoirs in the size group 100–500 ha showed the highest response of fish yield with respect to stocking of fingerlings. The size of fingerlings at stocking and area of the reservoir had greater impact on enhancing fish yield. Stocking had a profound positive impact on fish yield. This study forms a baseline evaluation of the impact of stocking on small tropical reservoirs in India. It also recommends management measures and discusses issues, and the way forward for sustainable fisheries enhancement in small tropical reservoirs in eastern India. 相似文献