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为研究不同养殖密度下微生物调控凡纳滨对虾(Litopenaeus vannamei)工厂化养殖排放水的水质状况,设置了3种放养密度(200、400、600尾/m~2),共9口养殖池,跟踪监测了对虾从苗期到养成期不同生长阶段排放水中氨氮、亚硝酸盐氮、硝酸盐氮、硫化物、总磷、COD、重金属等水质指标。结果表明,在3种放苗密度下,当对虾体长8 cm时,排放水的水质基本能达到海水养殖水排放要求的二级标准;当对虾体长≥9 cm时,排放水中无机氮的含量均不符合一级、二级标准。在采用微生物调控的凡纳滨对虾工厂化养殖条件下,放苗密度不超过600尾/m~2时,对虾生长前期养殖水质基本能达到排放要求,生长后期则需要采取一定的养殖废水处理措施,才能达到排放要求。 相似文献
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在对虾养殖过程中，水质控制是一个重要环节，它直接影响到对虾养殖的经济效益。笔者在对虾养殖主要季节，对厦门同安、翔安地区对虾养殖中比较主要的水质因子水温、盐度（比重）、溶氧、pH、非离子氨等进行监测，并对其变化规律进行初步探讨，现将情况报告如下。 相似文献
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本文通过分析在封闭式对虾养殖系统中几个关键生态环境指标对养殖对虾的影响,充分显示创造一个良好的、稳定的生态环境,是达到高效养殖目的行之有效的途径.在2001年进行的南美白对虾封闭式养殖试验中,我们把控制、改善养殖水环境作为重要环节,通过跟踪检测、分析虾池水质指标的变化情况,并及时采取改善措施,使对虾保持良好的生长状况,取得了很好的养殖效果. 相似文献
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<正> 近几年来由于虾病的大面积暴发和蔓延,对虾养殖受到重创,养殖面积大幅度滑坡,一些沿海地区的中国对虾养殖已不复存在。为探求中国对虾养殖中的一些问题,本人与有关人员对养虾池中的水质进行了一些测定,同时对对虾的养殖模式进行了一些探讨,现归纳如下: 1 水质情况 判断水质的好坏,除了简单的肉眼观察之外,还采取一些物理、化学的方法对水质进行了监测,监测内容包括:pH、溶解氧、温度、盐度、硫化氢、氨氮等。 相似文献
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随着我国对虾养殖规模的不断扩大和精养程度的逐年提升,对虾养殖的自我污染和病害的传播蔓延也日益加剧,严重危及对虾养殖业的健康发展.因此,探索和开发可操作性强、效果显著的养殖水质综合调控技术,通过优化和改善池塘养殖环境,减少对虾养殖废水的排放,提高对虾养殖生产的经济效益和生态效益,对推动我国对虾养殖业的可持续发展具有重要的意义.臭氧是一种强氧化剂,具有极强的氧化能力,能快速分解水中有机物,杀菌力较强.臭氧在水产养殖中的应用,可通过其氧化反应起到灭菌、分解有机物和提高水体溶解氧浓度的作用,从而净化和改善池塘养殖水质.近几年,臭氧在水产养殖生产中的应用研究越来越广泛.孙广明等(2000)曾采用臭氧处理水进行海胆育苗及单细胞藻类培养试验;陈淑琴等(2001)曾利用臭氧处理水开展虾、蟹幼体培育试验;柳超等(2009)将臭氧水处理技术应用于凡纳滨对虾的养殖生产;他们的试验研究均取得明显的效果,为臭氧在水产养殖生产中的应用积累大量的有用数据.本试验通过在凡纳滨对虾的精养池塘中通入微量臭氧,监测养殖水质的变化情况以及对虾摄食生长状况,探讨臭氧水处理技术的应用对养殖水质和对虾养殖效果的影响,为臭氧在水产养殖的应用和推广提供参考. 相似文献
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本文通过分析在封闭式对虾养殖系统中几个关键生态环境指标对养殖对虾的影响,充分显示创造一个良好的、稳定的生态环境,是达到高效养殖目的行之有效的途径。在2001年进行的南美白对虾封闭式养殖试验中,我们把控制、改善养殖水环境作为重要环节,通过跟踪检测、分析虾池水质指标的变化情况,并及时采取改善措施,使对虾保持良好的生长状况,取得了很好的养殖效果。 一、材料与方法 1.养殖品种与设施 养殖品种为南美白对虾,采用封闭式循环水养殖模式,其中:对虾养殖面积5 相似文献
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<正> 日本从1963年开始,首先在山口县秋穗地区进行日本对虾的养殖,以后在九州、西南群岛也开始养殖,其养殖产量如表1所示。这些地区1981年的养殖总产量为1666t,1988年增长到3020t。但熊本县、山口县因水质污染,养殖产量从1988年开始下降,到1990年日本对虾的养殖总产量仅2636t。台湾养殖虾的产量如表2所示。斑节对虾(台 相似文献
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<正> 本文就河口水经调配后用于中国对虾penaeus chinensis Osbeck 育苗的生产性试验进行研究。1987～1989年的生产实践证明,先用盐卤(浓缩海水)将河口水比重调高,再用 MgCl_2试剂提高镁离子含量,使 Mg~(2+)/Ca~(2+)比值调整达到一定范围,就可将调配水用于对虾育苗。 相似文献
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Droughts are likely to increase in frequency and severity with climate change, modifying the economic viability of inshore fisheries in regions of hydrological extreme. Variation in the revenue and profit associated with different mixtures of fishing methods between non-drought and drought conditions was examined for commercial fishing businesses in three estuarine and coastal systems in eastern Australia from 1997 to 2007. Mean monthly revenue decreased from 8 to 36% between non-drought and drought. Decreased mean monthly revenue was primarily attributed to reduced revenue generation from ocean prawn trawling (≥20%) and estuarine prawn trawling (≥34%) during drought. Fishing method diversity (measured by a modified form of the Shannon index) and mean monthly revenue were positively related; however, mean monthly profit decreased between non-drought and drought under a range of alternative cost scenarios. Reduced mean monthly profit was primarily attributed to losses from ocean prawn trawling (≥15%) and estuarine prawn trawling (≥30%) during drought. Although diversified harvesting behaviour increased revenue generation, initial results indicated that this marginal economic benefit could have been compromised by the greater costs associated with the increased diversification which reduced overall profitability. Results of this analysis indicated that the commercial fishing sector is a drought-affected industry in New South Wales. 相似文献
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Abstract Multivariate patterns in commercial fisheries landings, effort and revenue from three adjacent estuarine and coastal systems were examined in eastern Australia between 9‐month periods of flood (September 2000–May 2001) and drought (September 2002–May 2003). Patterns in species landings, methods of fishing effort and revenue per species were significantly different between flood and drought. Spearman’s rank correlations between Bray–Curtis similarity matrices for landings, effort and revenue indicated that patterns in fisheries metrics represented a mixed signal of ecological response and fishers’ harvesting behaviour. Flood and drought events were associated with shifts in the species composition of landings that were reciprocated between estuarine and coastal systems. Estuarine migrant species (e.g. school prawn Metapenaeus macleayi Haswell) primarily contributed to landings during flood, whilst marine estuarine‐opportunist species (e.g. yellowfin bream Acanthopagrus australis Owen) primarily contributed to landings during drought. Flood and drought events redistributed fisheries resources between estuarine and coastal systems, modifying the bioeconomic productivity of commercial fisheries. Results indicated that flood and drought events influence commercial fisheries by modifying landings composition, fishers’ harvesting behaviour and revenue generation. 相似文献
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Jason J. Danaher James H. Tidwell Shawn D. Coyle Siddhartha Dasgupta Paul V. Zimba 《Journal of the World Aquaculture Society》2007,38(3):367-382
The effects of different densities of caged Nile tilapia, Oreochromis niloticus, on water quality, phytoplankton populations, prawn, and total pond production were evaluated in freshwater prawn, Macrobrachium rosenbergii, production ponds. The experiment consisted of three treatments with three 0.04‐ha replicates each. All ponds were stocked with graded, nursed juvenile prawn (0.9 ± 0.6 g) at 69,000/ha. Control (CTL) ponds contained only prawns. Low‐density polyculture (LDP) ponds also contained two cages (1 m3; 100 fish/cage) of monosex male tilapia (115.6 ± 22 g), and high‐density polyculture (HDP) ponds had four cages. Total culture period was 106 d for tilapia and 114 d for prawn. Overall mean afternoon pH level was significantly lower (P ≤ 0.05) in polyculture ponds than in CTL ponds but did not differ (P > 0.05) between LDP and HDP. Phytoplankton biovolume was reduced in polyculture treatments. Tilapia in the LDP treatment had significantly higher (P ≤ 0.05) harvest weights than in the HDP treatment. Prawn weights were higher (P ≤ 0.05) in polyculture than prawn monoculture. These data indicate that a caged tilapia/freshwater prawn polyculture system may provide pH control while maximizing pond resources in temperate areas. 相似文献
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Lam My Lan Jean-Claude Micha Duong Nhut Long Tran Thanh Hai 《Journal Of Applied Aquaculture》2013,25(3):168-183
ABSTRACT The on-farm trials of rotational rice-prawn farming in a semi-deep water area in the Mekong Delta of Vietnam was carried out in six rice fields (0.7–1.0 ha) to evaluate the production and economic efficiency of using low and high cost feed on prawn culture in paddies at different densities. Two stocking densities of 4 and 5 PL/m2 were investigated. Two treatments of feed types (pellets only or a combination of pellets, trash fish, and snail meat) were applied at stocking 4 PL/m2. At the treatment of 5 PL/m2, prawns were fed a combination of pellets, trash fish, and snail meat. Prawns were stocked in the mid-April and harvested in mid‐November before the next dry season rice crop. Rice farming was started 3 to 5 days after prawn harvesting. By cull harvesting during the culture period, final mean weights of prawn ranged from 47.2 to 57.2 g/prawn and the male:female ratio at harvesting was 2.5:1.0. The prawn yield of treatment 5 PL/m2 was highest (630 ± 22 kg/ha). Net profits in treatments using the combination of pellets, trash fish, and snail meat were 861 ± 193 US$/ha to 1,019 ± 25 US$/ha for the prawn crop and 1,393 ± 71 US$/ha to 1,576 ± 180 US$/ha for the whole system (prawn crop + dry rice crop) and significantly higher than in treatment using pellet only (P < 0.05). Prawns fed on pellets or a combination of pellets and snail meat both offer similar results in terms of production and economics. The dry rice crop offered high cost benefit ratio (2.29–2.33) with low operating cost (414–434 USD/ha) and it made a better use in sustainable rice fields through the rotational rice-prawn system. 相似文献
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Fish communities were sampled quarterly over a 2-year period at sites along the estuarine gradient of two large coastal rivers, the Richmond and Clarence, located in eastern Australian (NSW). A total of 175 582 fish from 73 species was captured, with two species making up 65% of this total. Many fish species of economic importance in local coastal waters were captured, predominantly as juveniles. Multivariate analysis revealed three significantly different groupings of sites corresponding to the marine, brackish and tidal-freshwater zones of the two rivers. The two rivers were remarkably similar in terms of overall abundance and diversity of fish, and structuring of fish communities, despite a large-scale and intensive prawn trawling industry operating on the Clarence River. Dependency of fishes on estuarine habitats and the distribution of some of the dominant fish species in relation to estuarine gradients are discussed. 相似文献
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U. I. ENIN 《Fisheries Management and Ecology》1997,4(4):301-309
The life histories of the estuarine prawn, Nematopalaemon hastatus Aurivillius, and the brackish river prawn, Macrobrachium macrobrachion Herklots, were compared in relation to their seasonal exploitation patterns in the Cross River estuary, Nigeria. The period of intensive exploitation of N. hastatus (March to June) was outside the main spawning season (July to October), because these prawns migrate from the main fishing area in the estuary and near shore coastal waters into the deeper continental shelf waters to spawn. This probably contributes to their reproductive success and conservation of the stock. With M. macrobrachion , the peak spawning period and the major fishing season converge between July and September. These prawns also migrate from the fresh water into the major fishing zone within the estuary during the spawning season. This exposes the spawning population to intense human exploitation. On the basis of their spawning dynamics, M. macrobrachion requires more urgent management attention. An option would be a closed season for M. macrobrachion within the estuary during the spawning period. 相似文献
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综述了我国主要对虾养殖品种对蛋白质和各种氨基酸的营养需求和量化指标。分析了各品种对糖类的利用率，以及某些糖类在对虾免疫系统中的作用，并报道了对虾对糖类的需要量。 相似文献
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<正> 中国对虾虽为广盐性甲壳动物,但其对不同盐度的适应通常是通过渐变过程来实现的。高盐度培育的幼虾,移入低盐度海水养殖,要行淡化过渡,这是低盐度养殖中国对虾成功所在。反之,低盐度海水培育出的幼虾,能否直接进入高盐度海水养殖未见报告,笔者配合长江口渔场中国对虾增殖研究课题进行了试验,现报告如下: 相似文献