Ontogeny and development of the gastrointestinal system in Indian walking catfish (Clarias magur) during its early development

Fish Physiology and Biochemistry - Ontogeny of the digestive tract and its accessory organs and their further development in the Indian walking catfish (Clarias magur) were examined in larvae,...     

无公害流水养殖杂交鲟技术

鲟鱼在英国、古罗马和中国古代的皇室都被视为珍品,故有“皇帝鱼”之称。鲟鱼籽酱位列世界三大珍味之一,价格奇高不下,被称为“黑色黄金”。杂交     

Evaluation of freshwater prawn‐small fish culture concurrently with rice in Bangladesh

An integrated aquaculture of freshwater prawn (Macrobrachium rosenbergii) and self‐recruiting small fish mola (Amblypharyngodon mola) was conducted in farmers' rice fields at Mymensingh, Bangladesh. There were four treatments with three replications. Four stocking densities, 10 000, 15 000, 20 000 and 25 000 ha^?1, of freshwater prawn were applied. The stocking density of mola was the same (20 000 ha^?1) in all treatments. During land preparation, triple super phosphate (TSP) and murate of potash (MP) were applied at the rate of 150 and 75 kg ha^?1 respectively. Urea was applied at the rate of 200 kg ha^?1 in equally distributed three installments after 16, 45 and 65 days of rice plantation. Prawns were fed with commercial pelleted feed at 3–8% body weight. All water quality parameters were found to be within the suitable range for freshwater prawn culture. There was a homogenous abundance of plankton communities in all treatments. The results of a 4‐month culture period showed that the average production of prawn ranged from 222 to 388 kg ha^?1, mola 51 to 68 kg ha^?1 and rice 2 880 to 3 710 kg ha^?1. Significantly higher production of both prawn and mola was recorded in the plots where the freshwater prawn stocking density was 15 000 ha^?1. This treatment resulted in a net profit of USD 1100 ha^?1.     

Economic feasibility of Pabda and stinging catfish culture in recirculating aquaculture systems (RAS) in Bangladesh

Recirculating aquaculture system (RAS) is a unique approach that offers total control to culture a wide variety of aquatic species. As capital investment is higher for setting up RAS, it is necessary to conduct an economic feasibility analysis based on real data. A structured questionnaire was used to collect all economic and technical data on two catfish species, viz., Pabda (Ompok pabda) and Shing (Heteropneustes fossilis), cultured in an RAS farm. The ultimate objective was to estimate net cash flow, net present value (NPV), profitability index (PI), payback period, discounted payback period, internal rate of return (IRR), and sensitivity analysis to find out the best profitability indicators. The analysis revealed that the IRR were 4% and 16% for Pabda and Shing production, respectively. However, for Pabda and Shing productions, the payback periods were 15 years and 4 months and 6 years and 2 months, respectively. The NPV value was positive for Shing production and negative for Pabda. On the other hand, the PI was lower than one for Pabda production and higher than one for Shing production. Therefore, the results showed that the Shing production in the RAS facility could be economically feasible; however, Pabda production may not be viable in RAS due to lower production and longer culture period. This study may suggest that by increasing the production capacity of the farm and market price of the product through the proper supply chain and by decreasing the initial investment, cost of fingerlings and feed, profitability can be achieved in RAS in Bangladesh.

     

Effects of trichlorfon, fenthion, and diflubenzuron on the zooplankton community and on production of reciprocal-cross hybrid striped bass fry in culture ponds

The application of trichlorfon, diflubenzuron, or fenthion to fertilized culture ponds stocked with 5-day-old, reciprocal-cross, hybrid striped bass fry resulted in an initial reduction in the concentration of rotifers and longer-term alteration of zooplankton successional stages, including changes in concentrations of rotifers, cladocerans, and copepods. Culture ponds without applied chemicals had the highest concentrations of small rotifers when fry were stocked, followed by high concentrations of cladocerans, copepod nauplii, and adult copepods. Fry survival in untreated ponds was higher than in chemically-treated ponds. Initial high concentrations of copepods in some ponds corresponded with low fry survival. Untreated ponds that were filled at the time of broodfish spawning, and stocked with fry 5 days later, had the highest fry survival rates, corresponding with peak rotifer concentrations, followed by a typical zooplankton succession.     

Technical efficiency in tilapia farming of Bangladesh: a stochastic frontier production approach

Genetically improved farmed tilapia is increasingly getting popular in Bangladesh. It has high production potential. Its dominant production technology ranges from extensive to improved extensive particularly in the rural areas. This study estimates levels and determinants of farm-level technical efficiency of tilapia farmers of Bangladesh using stochastic frontier production function involving a model for technical inefficiency effects. Data from fifty tilapia farmers of Jessore district are used in the analysis. The mean technical efficiency level of the tilapia farmers is 78%, and thus, the farmers operate 22% below the frontier production. Inefficiency effect is significant, and age, education, income, culture length, pond age, pond depth, water colour and pond tenure, as a group, are significant determinants of technical inefficiency. By operating at full technical efficiency levels, tilapia yield can be improved from the current level of 7.36–8.96?tons per hectare. The decision to add or not to add inputs is sometimes taken arbitrarily and not based on technology requirement. There is a lack of understanding of the technology practices. Fisheries extension efforts are required for proper understanding of the technology practices, further adoption and spread. For promotion of tilapia production, quality feed and seed at affordable price needs to be ensured.     

益生素及其在鱼类养殖中的应用

论述了益生素的概念 ,益生素在鱼体内的作用机理及特点 ,益生素在鱼类养殖业中的应用 ,使用益生素应注意的问题     

Efficiency of oxbow lake management systems in Bangladesh to introduce cage culture for resource-poor fisheries

A total of 5488 ha of oxbow lakes in Bangladesh has recently gained importance as a potential fishery resource. The growing need to utilize this resource to a fuller potential requires consideration of cage culture by resource-poor fishing communities as a compliment to existing stock enhancement programmes. In the present study, the existing management systems of eight lakes are reviewed. Water quality was analysed with reference to the largest lake, i.e. Lake Baluhar. During the present study, > 100 cm transparency indicated the suitability of a lake for cage culture. Other water quality parameters, especially dissolved oxygen, ammonia and nitrite concentrations, also indicated suitability for cage culture. Non-fisheries activities, such as the use of agricultural pesticides in the lake catchment and jute retting in its basin, were identified as the most harmful to fish by the majority of the fishermen. An integrated pest management programme using rice–fish based rearing systems in the lake catchment is recommended. It is further recommended that a unified management system should replace the existing dispersed systems under different management bodies.     

北方地区杂交黄颡鱼池塘精养试验

<正>我国是世界第一水产品养殖大国,鲤鱼、草鱼是主要的养殖品种,然而在产量连年增加和消费量下降的双重影响下,鲤鱼和草鱼价格持续走低,传统水产养殖的利润越来越低。加上近年来养殖水质环境不断恶化及鲤鱼疱疹病毒病、鲤浮肿病的频发,养殖风险越来越大,近几年更是在亏本的边缘挣扎。随着我国经济快速发展,人民生活水平显著提高,水产品的消费逐渐由传统的鲤鱼、草鱼等常规鱼类向名特优鱼类转变,据调查,仅北京、天津等城市黄颡鱼的日销售量在20 000 kg以上,市     

梭子蟹的生物学特性与人工养殖潜力

梭子蟹(Portunus trituberculatus)学名为三疣梭子蟹,是大型海产食用蟹类。20世纪80年代初,我国山东沿海进行了土池育肥和蓄养试验,并取得了初步成功,目前我国的南北沿海池塘养殖及蓄养再度兴起,梭子蟹也成为虾池综合养殖的种类之一。一、梭子蟹的生物学特性1.形态特征梭子蟹属     

坤龙水库浮游生物调查及鱼产力分析

共检出浮游植物8门43属,生物量为20.57 mg/L。浮游动物生物总量为19.48 mg/L,大型浮游动物中晶囊轮虫和剑水溞为优势种类。水库总鱼产力1 098.73 kg/hm2。属富营养型水库,库水营养盐丰富,有利于浮游生物的生长繁殖。提出了持续发展水库渔业的对策。     

Sea bream culture in Egypt; status, constraints and potential

Marine fish farming in Egypt began in 1976 with the culture of gilthead sea bream, (Sparus aurata) as this fish was notably adaptable to brackish and marine pond conditions. Today, marine fish and shrimp farms amount to about 19,000 ha, out of which 42% is already in production while the rest, i.e., 58% is still under construction. In 1997, cultured gilthead sea bream production of 2,250 tons made up 3% of the 75,000 tons total aquaculture catch. In polyculture, usually with the grey mullet and sea bass, gilthead sea bream contributed 440 kg ha^–1 to the total yield of 1,700 kg ha^–1 (26%) over a period of 16 months. For the same period, the yield of monoculture ponds averaged 100 kg ha^–1, while in marine cages, yields ranged from 4–10 kg m³. In 1996–1997, fry of 0.25–1 g and fingerlings 1–10 g with a total of 3 million, were collected from the wild and 1 million fry were produced in the three marine hatcheries out of the four existing ones. The development of sea bream culture in Egypt is now severely inhibited by the shortage of seeds and adequate feeds. Exports of both sea bream and sea bass, during 1994–1996 averaged 1,300 tons per year.     

香鱼的人工养殖及饲料投喂技术

香鱼（Plecoglossus altiuelis）属鲑形目，香鱼科，香鱼属．为一年生小型经济鱼类。因脊背上有一条满是香脂的腔道。能散发出诱人的香味，因而得名。其肉质白嫩，无论脆炸、蒸煮或煲汤味道都十分鲜美、芳香．是食药兼得的美味滋补佳肴．尤其对产后妇女和病人更具滋补功效。目前国内市场香鱼鲜鱼收购价格每千克70～140元．日本1000～1500日元．加工成鱼干1000元以上，仍供不应求。该鱼食物链短、生长快．对温度及盐度等环境条件适应性强．开发养殖前景广阔。     

肉兔不同杂交组合的生产性能试验报告

选择适合本地的3个优良品种及6个杂交组合,探讨不同组合的产仔数、初生窝重、30日龄断奶窝重、30日龄断奶成活率、90日龄成活率、90日龄个体重等生产指标,筛选最优杂交组合。结果表明:肉兔不同品种杂交生产性能明显提高;最优杂交组合为大♀×加♂杂交组合和加♀×新♂杂交组合;6个杂交组合90日龄个体重平均增加109g。     

池塘养鱼增产增效的挖潜措施

1．从“深”字上着手。现在池塘大部分都是老池塘,老池塘连年淤积,水位越来越浅。要想达到高产,鱼种他和成鱼池水深应分别达到1．5～2．5m。生产实践证明,包地每增深0．5m,产量可提高10～30％。同时,一亩鱼池挖深0．5m,可取塘泥333m3,经有关科研单位测定：这些塘泥的肥效相当于144kg尿素,170kg过磷酸钙和44．4kg氯化钾,此外,还含有大量腐殖质,这些塘泥送进田地当肥料,可促使农作物增产。2从“种”上着眼。鱼种是池塘养鱼的物质基础。实践证明,投放鱼种的规格和数量与池塘养鱼的产量和效益有密切关系,高产池塘投放12cm以上的…     

浅海筏式养殖的几种增收方法

1997年以来,浅海筏式养殖的主导品种栉孔扇贝连续三年发生了大面积的死亡现象,栉孔扇贝的养殖优势如虾池养殖东方对虾一样跌入低谷。为此,我们渔技人员与广大养殖户一同探讨,采取了多品种混合养殖的模式,确保了浅海筏式养殖的健康发展。现把我们的做法总结如下,供同行参考。1．进行栉孔扇贝的换季养殖改变传统的春放冬收的养殖模式,购买当年培育的较大规格苗种或越冬渡夏的“老头苗”,把分苗时间提前至当年11月份,每层放苗40－50粒,第二年6、7月份收获,扇贝规格可达5－6cm,一般笼产6－8kg。2．进行海湾扇贝养殖搞好海湾扇贝养殖…     

Mass culture of fairy shrimp Streptocephalus proboscideus (Crustacea – Anostraca) and its use in larviculture of the Persian sturgeon, Acipenser persicus

This study was conducted with cysts of Streptocephalus proboscideus obtained from the University of Gent‐Belgium. The cysts were hatched in Environmental Protection Agency (EPA) medium. The nauplii were reared at the Sturgeon Research Institute using a pure culture of Scenedesmus obliquus alga supplied at a density of 5 × 10³ cell mL⁻¹ that gradually increased to 1 × 10⁴, 5 × 10⁴ and 1 × 10⁵ cell mL⁻¹ with the growth of the nauplii. The nauplii attained sexual maturity and started producing cysts in 8 days and yielded a mean cyst number of 220±40 female⁻¹ brood⁻¹ cysts. These cysts were used in the larviculture of Persian sturgeon, Acipenser persicus (Borodin). Forty‐three larvae of Persian sturgeon (mean weight: 15.4±1.1 mg; mean length: 27.1±2.7 mm) with roughly absorbed yolk sacs were stocked in three aquaria and fed S. proboscideus nauplii at 8‐h intervals. By the end of the experiment (day 5), the mean weight and length of Persian sturgeon larvae were 51.4±13.3 mg and 20.7±1.4 mm respectively.     

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     

Cage culture development and its role in aquaculture in China

Abstract. This paper is divided into four parts. First, history: cage culture has long been practised. The origin of cage culture world-wide should be regarded as the middle reaches of the Yangtze River, China, in the Sung Dynasty. Second, characteristics of cage culture in China. Third, influence: development of open-water fisheries is actively promoted in lakes, reservoirs and rivers. More kinds of water bodies have been employed for this purpose. Marine cages have also rapidly developed. Finally, discussion and conclusions. Cage culture is a modern development of aquaculture which has changed the long-established, fish-farming structures and, to a great extent, pushed forward fisheries development in China. Cage culture is typically characterized by intensive farming, running-water culture, high yield and great efficiency. It is generally accepted that cage culture will actively play an increasingly important role in international aquaculture.     

彩虹鲷及其养殖技术

<正> 彩虹鲷系鲈形目、丽鱼科。体型似真鲷,体腔无黑膜,肉质鲜嫩,营养丰富,且生长快、产量高、效益好,深受人们欢迎。1 生物学特性 彩虹鲷体色粉红或橘红,头小、体厚,初次性成熟在350g以上。 彩虹鲷属热带鱼类,耐低氧,对盐度适应范围