青鱼苗种培育试验

青鱼是我国四大家鱼之一,其孵化技术早在上个世纪60年代就已经研究试验成功。然而,由于当时饲料营养的研究不够,青鱼高密度集约化养殖的配合饲料问题无法解决。天然饵料,如螺蛳、河蚬等在我国大多数养殖地区都不能满足养殖的需要。更重要的是一龄苗种的饲料问题没有解决,严重的     

池塘养殖草鱼种关键技术研究

草鱼以其饲料来源广,肉质好,脂肪含量低,生长速度快,产量高,易于进行规模化养殖等特点,成为我国渔业生产中历史悠久的重要淡水传统养殖品种之一,与青鱼和花白鲢统称“四大家鱼”,深受广大养殖生产者和消费者的喜爱。随着社会的进步和人民生活水平的提高,人们对优质廉价的草食性     

池塘高密度培育草鱼鱼种技术

近年来,草鱼以其营养丰富,肉质鲜美而倍受消费者青睐,市场销售价格比鲤鱼等其它投饵型鱼类平均价格每市斤高出1.5元左右,而其生产成本却和鲤鱼等基本相同,广大渔农养殖草鱼积极性很高。但是草鱼鱼种的供给却成为制约草鱼成鱼养殖发展的瓶颈,采用传统的方式培育草鱼鱼种产量低、     

池塘泥鳅的人工繁殖及苗种培育技术

泥鳅,属鲤形目、鳅科、鳅属,它是一种经济价值较高的鱼类,具有较高的营养和药用价值,素有“水中人参”之称,深受韩国、日本等东、南亚市场的欢迎,且价高畅销,供不应求。目前我市养殖泥鳅的苗种,大部分是天然捕捞采集而来,优劣不等,远远不能满足市场需求,为了解决大面积养泥鳅苗     

循环水及生物絮团系统对大规格罗非鱼种生长及水质的影响

为比较越冬期循环水系统(RAS)与生物絮团系统(BFT)两种模式下大规格罗非鱼(Oreochromis niloticus)鱼种的生长性能与养殖水质的差异。选择RAS组与BFT组,进行为期67 d的养殖,测定养殖过程中罗非鱼种的生长情况以及水质的变化情况。结果显示,RAS组与BFT组增重率和特定增长率分别为(870.69±33.25)%、(3.39±0.05)%/d和(659.47±62.84)%、(3.02±0.13)%/d,RAS组显著高于BFT组;在水质控制方面,RAS组氨氮和亚硝酸盐从养殖初期到实验结束均维持在较低水平,而BFT组在初期氨氮和亚硝酸盐有升高的趋势,峰值分别达到了(4.53±0.72)mg/L和(6.68±1.8)mg/L,分别在第3天和第6天下降到较低水平,硝酸盐两组均呈现不断积累的趋势。结果表明,RAS系统养殖罗非鱼生长速度要高于BFT系统,RAS系统在水质控制方面略优于BFT系统。     

Experiments on rearing exotic carp fingerlings in composite fish culture in India

The results of four field experiments on rearing fry to fingerlings of mainly exotic carp, Hypophthalmichthys molitrix, Ctenopharyngodon idella and Cyprinus carpio var. communis conducted for three- and six-month periods during 1971–1975 are presented. In one experiment Labeo rohita, an indigenous species was also introduced as a compatible species. Fry were stocked at densities of 200 000 and 250 000 per hectare in the three-month period and at 100 000 and 250 000 per hectare in the six-month period.Under pond fertilization and supplementary feeding a high percentage of fingerling survival was recorded; the aggregate percentages ranging between 71.50 and 91.16 in the three-month period and 61.26 and 89.03 in the six-month period.     

外荡网箱养殖乌鳢技术要点

1993年我区大桥乡渔民在外薄利用网箱养鸟鳢取得成功后,近几年全区大力推广该项技术．1999年全区外落网箱养鸟鳢面积已达9258m’。1998年我区外荡网箱养鸟鳢平均亩产6377k吕,亩净收益63260元。现将外落网箱养乌鳢的有关技术要点作一介绍：一、募直水域条件的选择乌红耐低氧,对水质的要求不严格,一般具有一定的水深和阔度的外河水域均可发展马路网箱养殖。但根据乌红的生活习性宜选择水流不大、环境安静的水域,并且无污染。二、冈田的结构及其设互网箱的箱体采用聚乙烯夏花网片制成,规格宜小不宜大,一般每只面积以15－30Yn’为宜c网…     

大水面网围精养对水环境的影响及其对策

大水面网围精养对水环境的影响及其对策吴庆龙，陈开宁，高光，范成新，季江，隋桂荣，周万平（中国科学院南京地理与湖泊研究所，２１０００８）关键词网围养鱼，水环境，对策ＥＦＦＥＣＴＳＯＦＰＥＮＦＩＳＨＣＵＬＴＵＲＥＯＮＷＡＴＥＲＥＮＶＩＲＯＮＭＥＮＴＡＮＤ...     

Factors affecting fish yield and profit in fish pen culture in flooded ricefields

In recent years, a rotational system consisting of two rice crops followed by a fish pen culture during the monsoon flood period was adopted in parts of the flood-prone region of the Mekong Delta. In this paper, we use the survey data from 51 fish pen farmers at Co Do and Vinh Thanh district, Can Tho City, to investigate the factors affecting fish yield and profit in such fish pen culture system. The net yield of all stocked fish varies from 377 to 3,782?kg/ha/crop while the return above variable costs varies from ?5.3 to 9.8 million VND/ha/crop. Low fish price at harvest and the difficulty to sell below market sized fish at a period of oversupply are the main problems for fish pen culture. Fish net yield significantly increases with stocking density and is linked with specific polycultures. Common carp and bighead carp perform best in fish pen culture, both in production and profit considerations. Harvest body mass of common carp is mainly limited by increasing common carp stocking density. Therefore, a stocking density of common carp of about 6,000 fish/ha is recommended to obtain the optimum combination of reasonable body masses, and a good price, as well as a high return above fingerling costs.     

淡水白鲳的养殖技术之三豫西地区淡水白鲳鱼种温室越冬技术

豫西地区地处黄河中游，自然资源丰富，水源充足，气候适宜，年平均温度１２℃～１５℃，无霜期为１７０天～２３５天。自然条件下，适宜于淡水白鲳生长的期限为１２０天～１４０天即从每年的５月下旬至１０月上旬。适宜规格的淡水白鲳鱼种８ｇ～１０ｇ／尾左右在正常的放养密度范围内，经过４个月的生长期，足以长成商品鱼，并且可以实现高产稳产。因此，淡水白鲳在该地区具有较大的推广价值。但由于每年的５月份，规格在８ｇ～１０ｇ左右的淡水白鲳鱼种往往要靠上一年的秋苗经越冬培育所得，因此，淡水白鲳苗种的越冬问题在一定程度上直接…     

Cellulase activity in rohu fingerlings

The activity of cellulase was determined in the intestine of rohu, Labeo rohita, fingerlings fed on separate dietary formulations incorporating Leucaena leaf meal and synthetic cellulose at 20% level in proportional replacement of the ingredients from the fish-meal-based reference diet. Three more replicate experimental diets were prepared by incorporating 1% tetra-cycline, a broad-spectrum antibiotic, into the former three dietary formulations so as to circumvent the action of microflora in digestive function. Cellulase activity was found to be highest in fish fed on the cellulose incorporated diet, followed by those maintained on the plant-protein-based and reference diets, respectively. A diet-dependent variation in cellulase activity was apparent. However, a sharp decline in the level of cellulase activity was observed in the fish fed diets containing tetracycline, which is supposed to have destroyed all the gut microflora. The microbial culture of intestinal and hepatopancreatic extracts also confirmed the absence of microflora in the fish fed tetracycline-compounded diets. The study indicates that cellulase activity in rohu is largely contributed by the intestinal microflora, while the reduced activity recorded in the fish reared on antibiotic-compounded diets may be due to the presence of some other source of cellulase secretion apart from cellulolytic microbial action. The information generated from the present investigation might contribute towards better feed formulation for carp at low cost, incorporating plant-based feed ingredients. © Rapid Science Ltd. 1998     

River pen culture of giant freshwater prawn Macrobrachium rosenbergii (De Man) in southern Vietnam

A technical and socio‐economic survey conducted in the Dong Thap province of Vietnam to assess the current status of river pen culture of giant freshwater prawn Macrobrachium rosenbergii (De Man) showed that pen culture, which has been developed and operated by farmers' indigenous knowledge, requires more study in order to optimize stocking density and to assess its environmental impacts. In this study, the prawn pens were of rectangular shape, with an average size of 209 m². Prawns were stocked in June at an average density of 62 pieces m^?2 and fed on farm‐made feed and were harvested 2–4 times starting from 4 months after stocking until late December or the following January. The average prawn yield was 0.52 kg m^?2 year^?1, ranging from 0.14 to 1.6 kg m^?2 year^?1. The average net return was US$0.71 m^?2 year^?1, ranging from US$1.24 to 4.37 m^?2 year^?1. About 73% of the farmers achieved positive net returns. The top five constraints for prawn pen culture were lack of knowledge of culture technologies, poor water quality, disease problems, poor quality of wild seed and lack of capital. Almost all farmers have no environmental awareness, and environmental regulations for prawn pen culture have not been established. Field measurements showed that all measured water quality parameters were within the range for good growth of giant freshwater prawns, and indicated that there was no significant accumulation of nutrients and organic matter at the bottoms of rivers or canals.     

Moderate salinities enhance growth performance of Nile tilapia (Oreochromis niloticus) fingerlings in the biofloc system

The biofloc technology (BFT) has recently gained attention as an economic and environmentally sustainable system for aquaculture. The use of BFT with salinized water could be used to minimize the negative effects of nitrogenous waste and improve the growth performance of Nile tilapia. This work evaluated the growth performance, survival, gill lesions, and fillet composition of tilapia fingerlings (Oreochromis niloticus) reared during 70 days with different salinities (0, 4, 8, 12, and 16 g/L) in a biofloc previously developed. The results indicated that the use of mature bioflocs alone was sufficient to avoid fingerling mortality due to nitrite peaks. Moreover, the salinized water, especially between 4 and 8 g/L (maximum points around 6 g/L), can be recommended in BFT to improve the growth performance of tilapia in the initial culture phase. The salinity level that was evaluated did not affect fillet composition nor the occurrence of gill lesions. The total ammonia nitrogen concentration was lower in freshwater than in salinized water (p < 0.05). Nitrite peaks in salinities of 12 and 16 g/L appeared later and were higher in comparison to other treatments. Considering minimal water exchange in BFT, the use of salinized water in this system may be environmentally viable.     

Growth response of Tilapia zillii fingerlings fed isocaloric diets with variable protein levels

Six purified casein diets within a range of 21–53% crude protein were fed for 3 weeks to young tilapia (Tilapia zillii) to determine the optimum protein requirement and protein: energy ratio for growth. Growth rate increased proportionally to protein level of the diet to an incorporation rate of about 35%. Beyond this a gradual retardation in growth rate was observed. The diet containing about 30% crude protein with a protein: energy ($\text{P}\text{E}$) ratio of 81, however, appeared to be more efficiently utilized by the fish in terms of protein deposition and energy retention than diets with higher levels of crude protein. These results indicate that Tilapia zillii requires about 35% protein in the diet for optimum growth while 30% for the maximum bodily protein deposition when casein is used as the sole source of protein. All six diets, however, showed an excellent feed conversion. Protein efficiency ratio (PER) decreased with the increase in protein in the diet.     

Effects of aflatoxin B 1 on performance and health of tambaqui fingerlings ( Colossoma macropomum )

The detection of mycotoxins in feeds and their ingredients in aquaculture gained prominence due to losses caused in production and animal health, mainly the occurrence of aflatoxin (AFB1). The aim of this study was to evaluate the effects of AFB1 on the performance of tambaqui fingerlings (Colossoma macropomum). Four hundred tambaqui were used. Four different treatments were evaluated: treatment T1, considered as the control treatment (CT) with 3.84 μg kg−1; treatment T2, treatment T3 and treatment T4 with 500, 1000 and 2000 μg kg−1 of AFB1, respectively. The AFB1 of the samples (muscle, liver and kidney) was detected by high-pressure liquid chromatography. Four fingerlings from each treatment for histological analysis were examined. Moreover, the performance parameters (weight gain, feed conversion and feed intake) were studied. The levels of toxins used in T2, T3 and T4 represent a reduction in the growth of 14%, 35% and 45%, respectively. The T3 and T4 showed the lowest weight gain (78%) and the worst feed conversion. Aflatoxin B1 in muscle (3.28 μg kg−1) and kidneys (8.8 μg kg−1) in the T3, as well as liver (4.4 μg kg−1) and kidney (4.08 μg kg−1) in T4, was detected. Histopathological changes in liver and kidney tissues of fingerlings were more pronounced in T3 and T4. Fingerlings that consume feed contaminated with AFB1 in concentrations higher than 500 μg kg−1 present decreases in growth, reduction in weight gain and feed intake with increased feed conversion. The consumption of feed contaminated with 1000 and 2000 μg kg−1 of AFB1 caused severe deterioration in the hepatic and renal tissues.     

Mud crab pen culture: replacement of fish feed requirement and impacts on mangrove community structure

Brackishwater pond culture has been a major factor in mangrove loss in Southeast Asia, hence, the need to develop environment‐friendly technologies such as mud crab Scylla (Portunidae) culture in mangrove pens exists. This study evaluated the effects of mud crab netpen systems in central Philippines on mangrove macroflora, and the replacement of dietary fish with low‐cost pellets. Wild or hatchery‐sourced Scylla olivacea and Scylla serrata were stocked at 0.5–0.8 m⁻² in 167–200 m² nylon netpens (2.3 cm stretched mesh) in Avicennia‐dominated mangrove habitats. The feeding treatments were: (A) Zarraga: (1) no feeding (natural productivity), (2) no feeding for 1 month+supplementary feeding, (3) fish biomass and (4) low‐cost pellets, and (B) Batan: (1) fish biomass and (2) pellets+fish biomass. Feeds were given ad libitum twice daily. Growth and survival rates of S. olivacea in Zarraga pens were not significantly different among treatments, although crabs fed fish biomass had the highest survival, body weight and production. Similarly, growth and survival of S. serrata were not significantly different between the Batan treatments. Economic analysis of the latter gave a 38.5% return on investment (ROI) and 2.6 years payback period (PP) for pellets+fish biomass treatment compared with 27.5% ROI and 3.6 years PP for fish alone. Sensitivity analysis showed an improved economic performance of the pellets+fish biomass treatment by increasing the survival rate. Evaluation of mangrove community structure showed that crab culture reduced species diversity, numbers and biomass of seedlings and saplings, but not of mangrove trees. Therefore, mud crab pen culture is recommended for mangrove sites with mature trees, but not seedlings and saplings, and low‐cost pellets can reduce dependence on fish biomass.     

杂色鲍在高密度养殖条件下的生长速率

本文报道了在人工高密度养殖条件下,杂色鲍（Ｈａｌｉｏｔｉｓｄｉｖｅｒｓｉｃｏｌｏｒ）的相对生长率、特定生长率及生长速度与饵料、水温等环境因子的关系。结果表明,杂色鲍的饵料系数为１３．６６,饵料转化率为０．０７３２,增重倍数为６．０３。体重与体长生长速率（７～１２月）关系式为Ｗ＝０．３０３９Ｌ－６．１８８７。     

饲料中添加维生素C对翘嘴鲌鱼种生长及组织中抗坏血酸含量的影响

在翘嘴(Culter alburnus)鱼种基础饲料中添加相当于抗坏血酸含量为0 mg/kg、25 mg/kg、50 mg/kg、100 mg/kg、150 mg/kg、200 mg/kg和400 mg/kg的包膜维生素C(Vc),制成7种实验饲料,饲养初始体质量为(3.71±0.11)g的7组翘嘴鱼种8周,每个实验组包含3个重复。结果表明,摄食不添加Vc饲料的实验鱼成活率显著低于其他Vc添加组(P<0.05)。饲料中Vc添加量为0~50 mg/kg时,对鱼体增重有显著影响(P<0.05),鱼体增重随添加量的增加而上升。但添加量继续增大,对鱼体增重不再有显著影响(P>0.05)。饲料中维生素C添加量为0和25 mg/kg时,饲料效率和蛋白质效率低于其他各组(P<0.05)。试验饲料中Vc不同添加量对肝体指数和全鱼体成分无显著影响(P>0.05)。肌肉中抗坏血酸含量随饲料中Vc添加量加大而不断上升,二者呈正相关关系(P<0.05)。肝胰脏抗坏血酸含量在Vc添加量≤100 mg/kg时,随饲料中Vc添加量加大而不断上升(P<0.05),但高于此添加量时,则肝胰脏中抗坏血酸不再随添加量的上升而有显著变化(P>0.05)。分别以鱼体增质量和肝胰脏中抗坏血酸为指标,经折线模型(Brokenline model)回归分析求得翘嘴鱼种饲料中Vc的适宜添加量分别为53 mg/kg和97 mg/kg。[中国水产科学,2007,14(1):106-112]     

黄颡秋片鱼种培育技术

<正>黄颡鱼(Pelteobagrus fulvidraco Richardson)俗称嘎鱼、嘎牙子、黄腊丁等,是我国江河、湖泊中常见的小型底栖鱼类。因其具有较高的经济价值,已成为我国淡水养殖的重要鱼类之一。近几年来,随着黄颡商品鱼出口的拉动,黄颡苗种供不应求,由于黄颡鱼种的培育技术还不是十分成熟,黄颡秋片鱼种的成活率参差不齐,一些养殖户不了解其培育方法,导致成活率很低,因此有必要对这几年在生产中的养殖实践进行总结,供同行们参考。