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浅谈僵鳗产生的控制及促长措施养鳗业近年来随着国内外市场需求量的剧增而逐年发展扩大。但由于鳗苗放养密度、投饵等管理不当，导致僵鳗产生的比例居高不下，尤其是欧州鳗，高达３０％以上，僵鳗现已成为鳗场一种弃之可惜、养则不长的赘物，从而增大养鳗的成本。采取何种... 相似文献
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顺德市华星饲料厂在坚持以快速提高欧洲鳗(Anguilla anguilla)上市商品率、提高生长速度、提高抗病能力为主攻方向的指导思想下，根据欧鳗养殖的水体和泥土等自然环境特点，经过多次反复试验，设计出以土塘养殖为主体的从欧鳗培苗饲养到土塘饲养的优化饲料配方， 相似文献
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养鳗业近年来随着国内外市场需求量的剧增而逐年发展扩大。但由于鳗苗放养密度、投饵等管理不当,而造成僵鳗产生的比例高居不下,尤其是欧州鳗,高达30％以上。僵鳗现已成为鳗场一种弃掉可惜,养则不长的累赘物,增大养鳗的成本。采取何种措施来控制、减少僵鳗的产生和促进僵鳗的快速生长,已成为养殖者和科技人员的一个重要问题。现据笔者的实践经验与已报道过信息,归纳如下供同行者试用。 1控制、减少僵鳗产生的技术措施 相似文献
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所谓老头鳗，指的是经过一个养殖周期，乃至几个养殖周期的饲养，仍达不到100克以上商品规格的鳗鱼。多数老头鳗体色发黄，俗称“黄苗”。养殖场对此类鳗鱼颇感头痛，继续养殖，成本很大，却收益甚微，甚至亏本，放弃又很可惜。老头鳗究竟是如何形成的？出现老头鳗后该如何再培育？现简单介绍如下。1老头鳗的形成原因1．1白仔鳗养殖阶段（1）放养密度过高，由于饲料、溶氧的不足，而产生生长停滞的僵鳗，虽养殖一段时间后，体色发黑，但人土池后仍形成老头鳗。（2）白仔鳗驯食时，丝蛆蚓的投喂量、投喂次数少，部分小规格、体质差的鳗苗抢不… 相似文献
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鳗池罗氏沼虾高产养殖随着名特优水产品养殖的兴起，罗氏沼虾因个体大、生长快，养殖周期短、产量高、效益好，深受广大养殖者的青睐。近几年来，因鳗苗种价格昂贵，大量精养露天鳗池被空闲。利用鳗池条件好，进排水方便转产进行罗氏沼虾高产精养不失为一条创利途径。１９... 相似文献
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根据检测超标问题提出对鳗鱼养殖及对日出口的建议 总被引：1，自引：0，他引：1
我国内地的鳗鱼养殖业于20世纪80年代中期开始，起步虽然较晚，但发展迅速，产量增长很快。经过短短20年的发展，已成为世界鳗鱼养殖、加工和出口的主要地区，形成了集鳗苗培育、成鳗养殖、饲料生产以及烤鳗和鳗鱼副产品加工、出口一条龙的外向型产业。鳗鱼及制品是我国大宗出口创汇水产品， 相似文献
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Otoliths of glass eels and larvae collected from the Rio Minho (Portugal/Spain) as well as from the Iberian continental slope from the Bay of Biscay were analyzed by scanning electron microscopy. Preliminary data are presented on the total radius of the otolith and the width of the zone exhibiting a diffuse structure which, in the literature, is suggested to be the zone of metamorphosis. It was found that the radius increased from the development stage I through stage II to the glass eel stage (Vb). The width of the diffuse zone also exhibited an increase. Calculations of the dimensions of the diffuse zone of specimens older than stage I revealed that the area of metamorphosis amounts to about 28–60% of the total diffuse zone. From these results it is evident that part of the diffuse zone must have formed during a larval phase of retarded growth, during which no formation of daily growth rings takes place. Only the outer portion of the diffuse zone can be accounted for by the metamorphosis. For these reasons, an exact age determination by counting daily rings seems impossible. A determination of the oceanic life of the eel recruits is difficult for other reasons too: all earlier and recent studies have indicated that Anguilla leptocephali and their metamorphosis stages do not occur on the continental shelf, which could add an additionally high amount of time needed until arrival at the coasts. 相似文献
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One of the challenges that Recirculating Aquaculture Systems (RAS) are still facing is the risk that in RAS fish grow less than in flow-through systems due to the accumulation of substances originating from feed, fish or bacteria associated with the water re-use. The present study investigated whether RAS with high and low accumulation levels of these substances affect feed intake and growth of Nile tilapia Oreochromis niloticus, African catfish Clarias gariepinus, and European eel Anguilla Anguilla. One-hundred and twenty individuals of each species were used (start body weights: Nile tilapia 264.8 ± 8.3 g; African catfish 253.2 ± 2.1 g and European eel 66.6 ± 1.3 g). For a period of 39 days, growth and feed intake were compared between high and low accumulation RAS. HIGH accumulation RAS was designed for maximal accumulation of substances in the water by operating the system at nearly-closed conditions (30 L/kg feed/d), using mature biofilters and high feed loads; and (2) LOW accumulation RAS was designed to be a proxy for flow-through systems by operating at high water exchange rates (1500 L/kg feed/d), new biofilters and low feed load. HIGH accumulation RAS induced a reduction in feed intake (42%) and growth (83%) of Nile tilapia, as compared to systems that are a proxy for flow-through conditions. This effect was not observed in European eel and African catfish. The cause of this reduced feed intake and growth rate of Nile tilapia is still unclear and should be addressed in further studies. 相似文献
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目前，国内采用饲养日本鳗鲡的传统方法来饲养欧洲鳗鲡，内中存在两个问题：一是鳗病，其中狂游病发病急，死亡率极高，而红头病虽然发病稍缓，但极难治疗，死亡也较严重；二是各阶段的生长速度明显低于日本鳗鲡。本文对这两大问题进行探讨。 相似文献
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中草药添加剂对日本鳗鲡生长和非特异性免疫效应的研究 总被引：2，自引：2，他引：2
在基础饲料中分别添加0.5 g/kg、1.0 g/kg和1.5 g/kg的自制中草药免疫添加剂,配制成3种试验饲料,以基础饲料为对照组饲料,每处理设3个平行样,对体重为30~40 g的日本鳗鲡(Anguilla japonica)进行为期60 d的饲养试验,每20 d取样一次,以相对增重率、成活率和血清中的溶菌酶(LZM)、一氧化氮合酶(NOS)、碱性磷酸酶(AKP)和超氧化物歧化酶(SOD)活性为指标,探讨了中草药免疫添加剂对日本鳗鲡生长和非特异性免疫效应的影响。结果显示:饲料中添加中草药免疫添加剂可以显著提高日本鳗鲡的增重率,降低饲料系数(P<0.05)。试验组日本鳗鲡血清中的LZM、NOS、AKP和SOD等活性均高于对照组。因此,中草药免疫添加剂具有显著促生长和增强机体免疫能力的作用,建议在实际生产中的添加量为1.0 g/kg较为合适。 相似文献
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孔雀石绿对日本鳗鲡的背景污染试验 总被引：1，自引：0，他引：1
用高压液相色谱法检测孔雀石绿和隐性孔雀石绿,研究了水体使用孔雀石绿后,池塘底泥孔雀石绿残留和泥土背景污染导致的鳗鲡肌肉中孔雀石绿的残留和消除.连续使用三次孔雀石绿24 h后,水体中无孔雀石绿残留.池塘使用孔雀石绿溶液浸泡后,导致池底泥沙中孔雀石绿残留,部分采样点检测到隐性孔雀石绿于泥沙中残留.池底孔雀石绿的残留,将导致鳗鲡孔雀石绿在肌肉中的残留,隐性孔雀石绿将长期于肌肉中滞留.孔雀石绿背景污染的池塘,应改造至无背景污染后使用,才能保障鳗鲡无孔雀石绿残留. 相似文献
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D. J. Jellyman 《Ecology of Freshwater Fish》1997,6(2):108-115
Abstract— Both species of New Zealand freshwater eels (the shortfinned eel Anguilla australis and the longfinned eel A. dieffenbachii ) are widespread and abundant, supporting important commercial and recreational fisheries. This article reviews growth studies from 35 widely distributed sites throughout New Zealand and discusses factors that influence growth rates. Length at given age is characterized by high intra- and inter-population variability; growth rates for eels >30 cm are typically slow (2–3 cm per year) and linear, with females generally growing faster than males. Water temperature affects the length of the growing season, although growth rates are not correlated with latitude. Other factors suggested as affecting growth rates are eel density, quantity and quality of food, and interactions between both eel species. Al though growth of some New Zealand eel populations is the slowest recorded for any species of Anguilla , growth in culture can be rapid, similar to that of other temperate eel species. 相似文献
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本文总结了１９９５－１９９６年来龙岩山区欧鳗的养殖结果，平均体重每尾２．４克幼鳗经三个月的养殖，成活率达８０％，饲料系数０．７５以上，成鳗养殖成活率可达９５％以上，饲料系数平均０．５４。结果表明：控制欧鳗养殖水日交换量大于１００－１５０％，建立蓄水池，进行水处理，解决雨季鳗场用水，采用优质配合饲料，定期进行病虫害防治，特别是拟指环虫病的防治，是山区欧鳗养殖成功的关键。 相似文献