提高蟹苗质量的三个关键技术

<正> 蟹苗质量决定着养殖者的效益,养殖者对优质蟹苗的需求量愈来愈大,优质蟹苗的价格一直处于4 000～5 000元kg,每kg蟹苗可培育成200～300只/kg的扣蟹300～500kg,并且这种扣蟹在池塘中养殖,水质和密度适宜的条件下,6～8个月可达到80～100g/只;在水库、湖泊和较大的水体中养殖6～8个月可达到100～150g/只。那么怎样才能繁育出优质蟹苗呢?笔者结合实践经验总结出了优质蟹苗的繁育方法和技术。     

天然海水池塘生态培育河蟹苗关键技术

通过产前强化培育增强亲蟹体质,提高成活率和抗病力,所抱卵发育速度快且一致。对天然海水池塘要进行改造使之符合生态育苗的要求。通过饵料的培养与补充,保障幼体的营养。利用生态育苗技术在天然海水池塘培育蟹苗,667m^2水体可生产蟹苗40—50kg,用此蟹苗1kg平均可培育成150—200只／kg的扣蟹200～500kg。     

蟹苗的选用与运输

<正>蟹苗质量的好坏和运输成活率的高低是河蟹养殖成败的关键。为此,笔者根据多年从事河蟹育苗、蟹苗选用和苗种培育的经验,介绍一些选用蟹苗的技巧和运输方法,以供读者选苗时参考。一、蟹苗的选用蟹苗的质量受亲蟹的品质、水质、投饲方法、药品的     

强化活轮虫培育高产优质河蟹苗试验

在利用活轮虫培育河蟹苗高产优质试验过程中．对强化活轮虫的方法、幼体培育中的技术管理进行研究和应用。结果显示：亲蟹260只。育苗水体520m^3,生产优质蟹苗371kg。出苗量0．713kg／m^3。平均每只亲蟹生产大眼幼体1．43kg．平均大眼幼体1．5×10^5尾／kg,从蚤状幼体Ⅰ期到大眼幼体出苗时的育成率为73％。     

水泥池全封闭培育蟹苗技术研究

在水泥池中分5个试验组进行河蟹育苗试验。结果表明：设计试验条件下，单位产量可达0．048～0．062kg／m^3，300m^3育苗水体可产蟹苗14．4～18．6kg。Z1期布池密度在4万～6万只／m^3为宜。布池密度过高，将超过系统负载量，造成水质恶化，氨态氮和亚硝态氮超过蟹苗耐受范围，系统崩溃。     

提高河蟹工厂化育苗的产量及蟹苗质量的几点措施

随着市场经济的发展,河蟹做为一种高投入、高效益的新兴产业得到了迅猛发展。但综观各地育苗情况,产量不一,质量良莠不齐。有的育苗成本大、产量低,亏损严重;有的育苗场培育出的蟹苗体质弱、质量差,成活率低,给养殖者带来较大损失。提高工厂化河蟹育苗的产量和质量...     

盘锦市蟹苗生产喜获丰收

盘锦市2008年中华绒螯蟹土池生态育苗克服气候反常、多雨、低温寡照等诸多不良因素,采取亲蟹提纯复壮、抱卵数量增加、育苗池水层加深、饵料精心培养等措施,全市中华绒螯蟹土池生态育苗生产喜获丰收。一是土地池规模进一步扩大,盘锦市中华绒螯蟹土池生态蟹苗面积达653 hm2,同比     

河蟹生态育苗关键技术

<正> 在天然海水池塘利用生态育苗技术培育的蟹苗,以其适应能力强、成活率高、生长快,深受广大养殖者欢迎,蟹苗一直供不应求,因此河蟹生态育苗技术应用越来越广泛。但在应用这种技术时,很多人套用在河蟹育苗刚开始时所采用的育苗方式,结果造成蟹苗的单产很低,一般每667m~2水     

培育蟹苗的廉价饵料——淡水浮游动物

1993年,山东省东平湖蟹苗试验场在无更多水体培育卤虫无节幼体和丰年虫货缺价昂情况下,首用德州产淡水浮游动物育蟹苗试验成功。德州育仔蟹全用鲜品浮游动物作代用饵料,至今已推广到四省众多场家使用,效果均显著。一、浮游动物的捕捞加工、质量及储运山东德州市区水面,由于城市     

河蟹育苗的几点关键技术

河蟹育苗的几点关键技术随着“高产、高效、优质”渔业的建设和发展，江苏河蟹育苗生产迅猛发展，但许多单位的产量和经济效益不甚理想。笔者１９９５年在江苏启东天汾育苗场进行了河蟹人工育苗，育苗水体３００ｍ２（水深１．４ｍ），共育苗２８０ｋｇ，单产处于江苏首位...     

Improved techniques for rearing mud crab Scylla paramamosain (Estampador 1949) larvae

A series of rearing trials in small 1 L cones and large tanks of 30–100 L were carried out to develop optimal rearing techniques for mud crab (Scylla paramamosain) larvae. Using water exchange (discontinuous partial water renewal or continuous treatment through biofiltration) and micro‐algae (Chlorella or Chaetoceros) supplementation (daily supplementation at 0.1–0.2 million cells mL⁻¹ or maintenance at 1–2 millions cells mL⁻¹), six different types of rearing systems were tried. The combination of a green‐water batch system for early stages and a recirculating system with micro‐algae supplementation for later stages resulted in the best overall performance of the crab larvae. No clear effects of crab stocking density (50–200 larvae L⁻¹) and rotifer (30–60 rotifers mL⁻¹) and Artemia density (10–20 L⁻¹) were observed. A stocking density of 100–150 zoea 1 (Z1) L⁻¹, combined with rotifer of 30–45 mL⁻¹ for early stages and Artemia feeding at 10–15 nauplii mL⁻¹ for Z3–Z5 seemed to produce the best performance of S. paramamosain larvae. Optimal rations for crab larvae should, however, be adjusted depending on the species, larval stage, larval status, prey size, rearing system and techniques. A practical feeding schedule could be to increase live food density from 30 to 45 rotifers mL⁻¹ from Z1 to Z2 and increase the number of Artemia nauplii mL⁻¹ from 10 to 15 from Z3 to Z5. Bacterial disease remains one of the key factors underlying the high mortality in the zoea stages. Further research to develop safe prophylactic treatments is therefore warranted. Combined with proper live food enrichment techniques, application of these findings has sustained a survival rate from Z1 to crab 1–2 stages in large rearing tanks of 10–15% (maximum 30%).     

Rearing techniques and nutritional quality of two mysids from Gran Canaria (Spain)

This paper presents the preliminary results of different trials carried out with two species of mysids from Gran Canaria: Leptomysis lingvura (G.O. Sars, 1866) and Paramysis nouvel. Experiments lasting 21 days showed significantly higher fecundity and survival in L. lingvura than in P. nouveli (P<0.05). We also report the biochemical profile of both species fed 48‐h‐Artemia nauplii enriched with Easy‐DHA‐Selco^® for 7 days. A comparison of our results with those of for Artemia and rotifers, organisms frequently used as live food in aquaculture, showed that mysids have a high percentage of protein per dry mass (73.38% in P. nouveli, and 74.19% in L. lingvura). Furthermore, the percentage of docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA) and arachidonic acid (AA) in total fatty acids was higher in both species than that reported by Roo and colleagues for rotifers and Artemia. In addition to the content of these fatty acids, their ratios between them are also important for normal growth and larval development. We found that the ratio, DHA:EPA, was 0.85 0.02 and 0.89 0.01; the ratio, DHA: AA, 6.25 0.26 and 4.74 0.14; and the ratio, EPA:AA, 7.32 0.26 and 5.32 0.2, respectively, for P. nouveli and L. lingvura in cultures and these ratios do not significantly differ (P>0.05) from organisms in the wild. Here, we argue that as mysids are prey for many commercially important fish, cephalopods and rays, it is likely that the biochemical composition of mysids in their natural environment is “optimal” for these predators. Therefore, we studied the lipid profile of both species as they naturally occur in their environment. The results indicate that these mysids could be used to develop high quality live fish food.     

长江蟹苗、幼蟹丰收后思考

今年长江中化绒螯蟹幼蟹获得超历史丰收,仅崇明有１０００吨左右,约是去年总量的３倍,１９９９年长江口中华绒螯蟹在沉寂长达９年以后,在完全出于人们意料之外的情况下再次旺发,仅崇明就捕获蟹苗４０００公斤左右,有关人士认为整个长江口产量高达１２０００公斤。蟹苗、幼蟹丰收给上海的宝山、南汇,尤其是崇明等县（区）的养殖户及其流通领域的经营者带来了巨大的经济效益,为长江中下游乃至全国相当地方的养蟹业提供了大量的优质蟹种,那么,今后如何使长江口蟹苗长捕不衰,如何保持为全国各地源源不断地提供大量的优质蟹种,这是值…     

欧鳗苗种培育技术

近几年 ,欧洲鳗的养殖迅速崛起。如何克服欧鳗地理上的差异 ,提高成活率 ,将白仔鳗顺利培育成大规格的黑仔鳗种 ,是整个欧鳗养殖的关键。笔者在多年的养殖实践过程中 ,总结出以下四点技术关键。1　把好苗种关投放优质的鳗苗 ,是整个苗种培育的基础。目前 ,我国欧鳗养殖的苗种主要产于法国、英国、西班牙等 ,其中法国产的鳗苗最佳 ,较能适应我国的环境 ,且鳗苗个体整齐 ,一般在 2 80 0～ 380 0尾 ｋｇ。优质的鳗苗应通体透明 ,体表无任何白点、白斑或白浊物 ,肠道未见进食 ,个体大小均匀 ,游动敏捷 ,逆水有力 ,对光敏感 ;入池后 ,能迅速集群…     

扣蟹培育实用技术要点

养殖扣蟹的池塘，要求近离水源充足、水质良好、上游无污染源，土质以粘土或粘砂土为适宜。池塘的模式有四种： １、池塘式：其形状为长方形或正方形，如养鱼池塘，面积１－１０亩左右，池水深１．２－１．５ｍ；也有的池塘中间剩１／３的浅水平台，平台水深 ０．２－０．３ｍ；池塘两端建有进排水设施，进排水口均要安装６０目网纱的过滤网，防止敌害鱼虾入池和扣蟹的逃逸。池塘坡比为１：３。池塘式养殖扣蟹投放苗量为每亩放大眼幼体１ｋｇ，或豆蟹３万只。 ２．稻田养蟹式：通常采用在稻田四周开挖环沟，环沟的宽为２－２．５ｍ，沟深为…     

蟹苗质量与河蟹Ⅰ期仔蟹成活率关系的探讨

近年来从春节前后的早繁蟹苗到6月份的后期蟹苗,在大限幼体培育成Ⅱ期仔蟹的过程中,中华绒螫蟹（河蟹）Ⅰ期仔蟹大量上滩死亡,给养殖者带来了巨大的损失,也给正常的养蟹生产带来了影响,为此,笔者根据1994年至1999年的多年从事河蟹工厂化育苗技术研究及仔蟹死亡原因课题研究的结果,对蟹苗质量鉴别、蟹苗质量与1期仔星成活率的关系及其蟹苗选购技巧及健康育苗技术作一介绍。从健康有苗及蟹苗质量鉴别方法上入手,以促进健康育苗技术的应用研究和规范发展,为河蟹健康养殖提供参考和指导。一、不同质量大眼动作的表观情况相差很大优质蟹…     

无公害鱼蟹混养效益好

从2005年4月19日起,8.5hm2池塘放养120~150只/kg的扣蟹7.68万只,经过7个月无公害养殖试验,河蟹共存活4.99万只,成活率65%,平均体重0.158kg/只。总产值54.48万元,总效益34.53万元,投入产出比1∶2.731。由此可见,池塘无公害养殖河蟹效益显著,值得推广。     

Rearing of sturgeon (Acipenser baeri Brandt) larvae: 2. Protein metabolism: Influence of fasting and diet quality

Protein metabolism was analysed in sturgeon larvae fed either on a natural food (Tubifex — diet 1, control) or on various artificial foods: mixed liver- and yeast-based diet (2), salmon starter diet (3) and casein-gelatin-based diet (4) (experiment I), or starved during 24 h (experiment II). Two pathways of protein metabolism, viz, protein synthesis and arginine oxidation, were measured in whole fish after immersion in a solution containing L-¹⁴C(U)-arginine.During short-term fasting, there was a large decrease in protein synthesis (from 220 to 10% day within 24 h) and only a small increase in arginine oxidation (from 1.9 to 4.7 μmoles of arginine oxidized per g body weight/day).In fish fed on an artificial diet, an improvement in performance (increasing from diet 4 to diet 2), assessed by growth and survival, led to an increase in protein synthesis and in the oxidation of arginine. Thus, the overall amino acid metabolism was stimulated.Fish fed on natural food showed a better efficiency of protein metabolism, associated with a lower rate of protein synthesis and a lower rate of arginine oxidation, than fish fed on artificial food.These changes in whole fish protein synthesis could be linked both to a change in protein deposition rate in muscle and to a change in protein turnover rate of active tissues such as liver, pancreas and digestive tract in response to different feeding conditions (namely feeding frequency and diet composition).     

鳜鱼苗种培育技术

鳜鱼,又称桂鱼、桂花鱼、季花鱼、花鲫鱼等,其肉质丰厚坚实,洁白细嫩,味道鲜美,肌间刺少,营养丰富,蛋白质含量高,是驰名中外的淡水名贵鱼类之一,是我国目前淡水养殖中最有发展潜力的优良品种,为广大养殖经营者所普遍看好。但是其苗种来源比较有限,关键在于苗种培育技术没有全面