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利用塑料大棚暂养早繁对虾苗,可使对虾提早放养,提早起捕,并可开展二茬养虾和虾池的综合利用,有利于提高对虾养殖的综合经济效益。为此,我们于1990年组织有关单位开展了塑料大棚暂养早繁虾苗试验,取得了初步结果。 相似文献
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车虾，即日本对虾，近两年以其产量高、价格好而受到养殖户的欢迎，但因种种原因，养殖产量不一，效益相差悬殊，有的甚至亏损。养殖户赵聚财、王长福等人在东营莱洲湾地区养殖车虾取得较好效益，他们的成功措施主要有：一、适时早放，以利提早上市实行早放，可使虾苗早适应环境，早日生长，利于提早上市，提高经济效益。实践证明：有时早上市５～１０天，价格往往比集中上市时要高１／２，甚至更多，这样就可大大增加养殖效益。一般当水温稳定在１２～１３℃时就应及时放养，有条件的也可利用温室大棚进行提早暂养，这样更利于早放，效果更… 相似文献
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<正> 近两年来,我们开展了提早家鱼繁殖的研究,以期充分利用鱼类生长季节,延长生长期,培育大规格鱼种,提高商品鱼规格,为缩短饲养周期,增加养鱼产量,降低养鱼成本创造条件。1978年提早草鱼繁殖试验于4月27日获得成功,比常规生产提早约半个月。1979年 相似文献
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<正> 近年来,我国对热源的渔业利用,已取得了一定的成效。例如,利用电厂余热进行高密度温流水养鱼和提早家鱼人工繁殖,利用太阳能和地热水提早家鱼人工繁殖等,这些对促进我国淡水渔业的发展起了重要的作用。现就渔业利用热源的几个问题,浅述如下。一、利用地热提早家鱼人工繁殖的意义渔业对各种热源的利用途径是多方面的,如全天候的鱼类遗传育种研究、温流水养鱼以及家鱼提早繁殖等。但目前主要侧重在 相似文献
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淡水养鱼鱼种的放养期,过去多习惯在三月间,个别也有在一、二月或头年的十二月下旬放养.近年来,渔农们在生产实践中,得到了提早放养期可以增产的经验,因而,大多提早在一月份或在头年的十一、十二月放养.提早鱼种的放养期对鱼种的运输、放养后的摄食,及对鱼类的成长等,好处都很多.首先,提早放养有利于鱼种的运输.冬季气候冷,水温低,鱼种体质坚实,鳞片紧缩活动力迟缓, 相似文献
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确定性前沿模型及其在测定我国农户精养淡水鱼技术效率中的应用 总被引：2，自引：0，他引：2
研究概述了确定性前沿模型的产生、分类、特点、参数求解方法及其在我国的应用现状。在此基础上,以2002年和2003年我国农户精养淡水鱼成本收益资料为样本,应用前沿模型理论建立了我国农户精养淡水鱼的确定性统计前沿模型并测定了这两年中我国主要淡水鱼养殖省市的农户精养淡水鱼技术效率,得出结论为:物质资本投入对我国农户精养淡水鱼产出的影响远大于劳动力投入;我国农户精养淡水鱼生产处于规模报酬不变阶段;我国农户精养淡水鱼生产存在着较大的技术无效性和管理缺失现状,这一现状存在着明显的地区差异和时间差异。 相似文献
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The aquaculture industry needs a simple, inexpensive and safe method for the treatment of fish waste without heat. Microbial inactivation by inorganic acid (HCl) or base (KOH) was determined using infectious pancreatic necrosis virus (IPNV) as a model organism for fish pathogens. Salmonella and spores of Clostridium perfringens were general hygiene indicators in supplementary examinations. IPNV, which is considered to be among the most chemical‐ and heat‐resistant fish pathogens, was reduced by more than 3 log in 4 h at pH 1.0 and pH 12.0. Salmonella was rapidly inactivated by the same treatment, whereas spores of C. perfringens were hardly affected. The results indicate that low and high pH treatment could be particularly suitable for fish waste destined for biogas production. pH treatment at aquaculture production sites could reduce the spread of fish pathogens during storage and transportation without disturbing the anaerobic digestion process. The treatment could also be an alternative to the current energy‐intensive steam pressure sterilization of fish waste to be used by the bioenergy, fertilizer and soil improver industries. 相似文献
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Puffer fishes of the order Tetradontidae exist in both anadromous and non-anadromous seawater resident forms. The obscure puffer akifugu obscurus is an anadromous species whose intensive culture in freshwater has developed rapidly in China. To mass produce larvae for intensive culture, induction of ovulation of 3-year-old obscure puffer cultured entirely in freshwater was attempted by giving the fish multiple injections of LHRHa. Twenty 3-yearold cultured obscure puffers were treated with multiple injections of LHRHa at a constant dosage of 30 g of LHRHa kg-1 of body weight with 36 h interval between injections. Beginning two days after hormonal treatment, abdominal palpation was performed every day to check expansion and hardening of the abdomen of the fish due to hydration of oocytes that indicates the completion of final oocyte maturation. The first four fish ovulated after the second LHRHa injection on day 3, but most females ovulated after the fourth hormone injection. A total of 18 fish (90%) ovulated over a period of 7 days, while no fish ovulated in the control group. The mean fertilization rate and the mean hatch rate was 67.1% and 87.6%, respectively. The viability of newly hatched larvae was very good, with a high survival rate of 98.6% 24 h post-hatch. These results indicate that cultured obscure puffer, which are not allowed to undergo diadromous migration and are entirely cultured in freshwater, could be induced to complete maturation and ovulate by simple multiple injections of LHRHa and that the eggs could be successfully hatched into viable larvae. 相似文献
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The hydraulic behaviour of any fish-containing tank, pond or silo is of central importance to all aspects of intensive fish rearing. The reticulation of fluid and local fluid velocities in particular systems will directly and indirectly affect fish physiology and metabolic rates in the intensive rearing process. It is also recognised that the fluid also has an important role to play in food and heat distribution and removal of waste solid material.This paper therefore reviews the design constraints placed upon such systems in the context of previous studies as an indicator as to how to make the most efficient use of square tanks for intensive fish rearing, which is the subject of Part 2 of the paper (Klapsis and Burley, 1984). 相似文献
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Khem R. Sharma 《Aquaculture Economics & Management (Blackwell Science)》2013,17(2):131-141
Abstract The main objective of this study is to examine technical efficiency and its determinants in carp pond culture in Pakistan. A stochastic production frontier involving the model for technical inefficiency effects is applied separately to the samples of semi‐intensive/intensive and extensive carp producers. The mean technical efficiencies for semi‐intensive/intensive and extensive farms were 0.673 and 0.561, respectively. By operating at full technical efficiency the semi‐intensive/intensive farms could, on average, increase their production from 3.0 to 4.5 Mt/ha and the extensive farms from 2.6 to 4.6 Mt/ha. Much of these efficiency gains would come from the improvement in fish, water and feed monitoring and management. Besides improving technical efficiency, potential also exists for raising carp productivity through increased intensification and technological progress. However, the realization of these potentials will depend on continuous government support for adequate provision of inputs, market and infrastructure, technology transfer and development and extension and credit services to carp farmers. 相似文献
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报道了在集约化养殖条件下４～２０月龄暗纹东方的生长特征。其中体长、体重的相对生长率和生长指标皆随月龄增加而逐渐下降。体长与体重呈指数曲线相关，方程为，体长、体重的生长方程分别为Ｌ＝１１９．５６Ｌｎ（ｔ）－９０．４６９，Ｗ＝０．４１２７ｔ。试验表明，暗纹东方纯在集约化养殖条件下具有良好的生长潜力，可进行规模化商品鱼养殖。 相似文献
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Luis Alvarez‐Lajonchère Leonardo Ibarra‐Castro 《Journal of the World Aquaculture Society》2012,43(5):607-620
Growth rate is one of the main biological criteria for selecting tropical marine fishes for intensive culture. Relationships of maximum observed length (MOL), length at first sexual maturity, growth performance index (Φ′), and juvenile absolute growth rate during nursery with growth rate during grow‐out periods were studied and their equations were calculated for 30 tropical or subtropical marine fish species. All equations were positive and their correlation coefficients were significant (P < 0.01). Three nomographs were made to obtain gross estimates of probable growth rates on intensive fish culture using the above relationships. Species with MOL of 100 cm or larger, length at first sexual maturity of 35 cm or more, Φ′ of 2.90 or more, and growth during the nursery period of or above 0.3 g/d, would be expected to have growth rates of at least 2 g/d during the grow‐out period. These criteria could help to identify species with best potential for intensive cultivation as a first step before a full evaluation and selection process is carried out. 相似文献
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Hirla Fukushima Jhon Edison Jimenez Marcos Weingartner 《Journal Of Applied Aquaculture》2013,25(2):147-156
The performance (growth and survival) of diploid and triploid jundia, Rhamdia quelen, was evaluated at six different stocking densities (10, 60, 110, 160, 210, 260 larvae/liter) during 31 days after rearing in an intensive larviculture system. Triploid fish exhibited a significantly higher survival rate than diploids at all stocking densities (27.1 ± 4.3% vs. 12.1 ± 3.3%; P < 0.01). Survival was not affected by stocking density (P > 0.05). Length gain was not affected by either ploidy or stocking density. Diploid fish gained more weight than triploids (P < 0.05), though this difference could result from lower fish densities in diploid treatments resulting from the higher mortality rate of diploid fish. This hypothesis is strengthened by the higher biomass present in triploid treatments (P < 0.01). 相似文献
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Technical efficiency of carp production in India: a stochastic frontier production function analysis 总被引：1，自引：0，他引：1
This paper aims to examine the levels and determinants of technical efficiency in carp pond culture in India. The stochastic production frontier technique involving the model for technical inefficiency effects is applied separately to samples of semi‐intensive/intensive and extensive carp producers interviewed during 1994–95. The results showed significant technical inefficiencies in carp production in India, especially among extensive farms. The mean technical efficiencies for semi‐intensive/intensive and extensive sample farms were estimated to be 0.805 and 0.658 respectively. By operating at full technical efficiency levels, the semi‐intensive/intensive farms could, on average, increase their production from about 3.4 Mt ha?1 to 4.1 Mt ha?1. Likewise, the extensive farms could increase their production from 1.3 Mt ha?1 to 1.9 Mt ha?1. Much of these efficiency gains would come from improvement in the adoption of recommended fish, water and feed management and monitoring practices. Besides expanding production area, the results indicated several other possibilities for increasing carp production in India by increasing yields per hectare, such as: (1) increased intensification of carp culture (i.e. moving from extensive to semi‐intensive or intensive systems); (2) improvement in technical efficiency at the farm level; and (3) technological progress. However, the realization of these potentials will depend on continuous efforts by the government in ensuring an adequate supply of inputs, technology transfer and development and adequate provision of research, extension and credit services in aquaculture. 相似文献
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AndréG. Coche 《Aquaculture (Amsterdam, Netherlands)》1978,13(2):157-189
The rearing of fish in cages could greatly contribute to increasing fish production in existing inland waters. Although it presents numerous advantages, its limitations and possible inconveniences must be borne in mind. Well-developed technology is available mainly from the Democratic Republic of Germany, The Netherlands, Japan, the U.S.A., the U.S.S.R. and the Lower Mekong region. Research is currently pursued in numerous other countries, where the use of floating cages in fish culture is becoming increasingly diversified.The most popular fish species used in intensive cultural systems are Cyprinus carpio, Ictalurus punctatus and Salmo gairdneri. In the semi-intensive Asian systems, Barbus spp., Pangasius spp. and murrels are among the favourite cage-reared fishes. Tilapia aurea and Tilapia nilotica have also proved to be well adapted to cage culture. Polyculture is only rarely practised.Floating cages seem to be the best suited for fish culture in most cases. Net cages are the simplest in design and the cheapest to build. The escape of fish, however, always remains an eventuality which might lead to choosing more expensive designs. Maintenance of cages must be regular. For flexibility of exploitation, cages should not be too large. Their location within the water body can play an important role in keeping production high.At high stocking rates, artificial feeding of a well-adapted diet is a necessity. Optimum conversion rates require a well-adjusted daily ration, possibly fractioned. Mechanized feed distribution is to be encouraged as a labour-saving practice. Less intensive systems rely more on locally available wastes, such as trash fish, but the feeding rate then depends mostly on feed prices.Best growth is generally achieved by C. carpio and I. punctatus. Attainable maximum production is as high as 35 kg/m3/month under intensive management. However, generally, production averages from 5 to 30 kg/m3/month for these two species. S. gairdneri is less productive. T. aurea and T. nilotica have both a very good potential. Production in less intensive systems varies greatly according to management practices. 相似文献