黑Jun工厂化育苗技术研究

研究了亲鱼选择、暂养和苗种的饵料转换、日常管理和病害防治等一套工艺流程，在３００ｍ＾３育苗水体中，育出２６．７ｍｍ以上黑Ｊｕｎ鱼苗３２．１５万尾，鱼苗培育成活率３３．５％。专家鉴定认为，本成果总体达国内先进水平，其中产仔率、单位水体出苗量等方面属国内领先。     

真鲷全人工工厂化育苗技术研究

利用人工培育和海捕的真鲷亲鱼，进行自然产卵，而后观察了真鲷胚胎发育过程，用小型轮虫、微胶囊饵料配合蛋黄，海湾扇贝卵作为开口饵料，进行鱼苗前期培育，以鱼、虾、蟹肉糜为饵料进行后期培育。在４３４．８ｍ＾３水体中，一次育出体长０．４９￣２．５０ｃｍ的真鲷仔稚鱼４８４万尾。专家鉴定认为，单位水体育苗量进入国际先进行列，居国内领先水平。     

鱼苗下池防感冒

由于温度的变化。鱼苗下池稍不注意，就会引起感冒，轻则影响生长，重则造成批量死亡，1989年4月，．桃江、安化等县从广东省购进家孵鱼苗1500万尾，因两地温差较大，加上下池遇上寒流，鱼苗死亡约1100万尾．成活率仅26％。鱼苗下池患感冒是生产中常见而又易忽视的一种鱼病。鱼类是变温动物，其体温随水温的高低而升降。但鱼体温和周围水体的温差大约为0．1℃。     

浅谈鱼苗鱼种生产体系建设

鱼苗鱼种是发展成鱼生产的物质基础。鱼苗鱼种生产又是一种特殊的商品生产，菌种不足、苗种过剩、或是品砷、规格不对路都不能充分利用水体、饵料或产销脱节，经济效益差。因此．必须建立一个与成鱼生产发展和市场需求相适应的鱼苗鱼种生产体系。现根据我市丘陵地区的特点，对今后鱼苗鱼种发展的方向、任务与措施，浅谈一些看法。     

小水体高密度培育革胡子鲶鱼苗的试验

关于革胡子鲶鱼苗培育，不少人做了许多工作，得到了良好的效果。但是，这些实验所用的培育池都比较大，鱼苗密度也较小。1984年，在孵化生产中，我们用水体面积分别为1.9m^2、1．54m^2和2．85m^2水池高密度培育鱼苗，取得了较好的效果。1985年，我们用这些培育池作了革胡子鲶鱼苗放养密度和充气与不充气对鱼苗的影响，     

光合细菌对罗非鱼鱼苗养殖水质及抗病力的影响

向罗非鱼鱼苗的养殖水体中投入光合细菌,研究不同浓度光合细菌对罗非鱼鱼苗养殖水体水质和鱼苗免疫力、成活率的影响.结果表明,水体中引入光合细菌浓度为4.5×102～4.5×106 cfu/mL时,各试验组的氨氮和亚硝酸盐氮含量都显著低于对照组(P<0.05);当浓度为4.5×104 cfu/mL时,罗非鱼鱼苗的抗病力增强,表现在鱼苗体内的组织过氧化物酶(POD)、碱性磷酸酶(AKP)、超氧化物歧化酶(SOD)、溶菌酶(LSZ)和抗菌活力都显著高于对照组(P<0.05),罗非鱼鱼苗的存活率也提高了6.67%.适宜浓度的光合细菌,能有效改善鱼苗养殖水体的水质,提高鱼苗免疫力和成活率.     

春季鱼苗投放水体后环境不适引起的常见死亡原因

正春季鱼苗投放后常引起鱼苗大量死亡,部分水体放鱼苗后近乎全部死亡。为恢复生产,需要重新放苗,部分水体要2~3次重复投苗才成功。这不仅带来极大的苗种成本,且耽误了鱼生长时间,部分鱼当年不能上市。本文就常见的春季鱼苗投放后引起死亡的环境和人为原因进行阐述。一、水质差异苗种培育水体和目标投放水体的水质差异大,温度、溶解氧、pH、硬度、氨氮、亚硝酸盐、硫化氢、有毒物质等有差异,这些指标中有些容易检测,有些检测难度大或成本高。小提议:两地     

美国红鱼淡化驯养试验初探

美国红鱼苗采用海水比重日递降幅度不超过０．００２的速度淡化，共历是１３天，并在纯淡中摄食生长１０天左右后，出现暴发性死亡。本文就此作了初步分析，认为与水体的Ｐ值、硬度等因素有关。     

鱼苗培育十要点

1鱼苗池选择面积0．2－034hm2，水深～l．5m，池堤坚实，不漏水，水源充足，注排水方便，鱼池要背风向阳，长方形，东西向。鱼苗池不宜过大，水体不宜过深，过大容易形成风浪，鱼苗随风浪与池壁碰撞，影响成活率，过深，水温难以提高。面积过小，水温变化快，鱼苗生活条件难以控制。2鱼苗放养前要彻底清塘鱼苗放养前10d，抽干地水，清除杂草，挖去过多淤泥，每公倾用块状生石灰1500kg化水后全池泼洒，杀死病菌、寄生虫和敌害生物。进水时，进水口要用双层峦网过滤，以防野杂鱼类进入池中，鱼苗池进水后，每天早晨要定时巡塘，发现蛙卵和水草…     

加州鲈池塘养殖试验

加州鲈又名大口黑鲈，原产北美洲，是美、加两国内陆放流增殖和池塘养殖的主要鱼类，１９８３年引入广东，１９８５年国内人工繁殖成功。后推广全国各地，现池塘、湖泊、水库等各种水体养殖均见报道。我们于１９９８、１９９９两年进行了该鱼的池塘养殖，已初见成效，现报道如下： 一、材料方法 鱼苗于１９９８年７月５日购于沈阳市苏家屯区新华畜牧场，尾数７０００，规格３－５ｃｍ，养殖池塘面积３．５亩，水深１．５ｍ，地下水源，池塘周围有芦苇，约占总养殖面积的１０％。 二、池塘养殖及日常管理 １、清塘．放养前５天用生石灰清塘，…     

黑鮶控光育苗技术研究

利用体重1～4kg的怀仔黑亲鱼56尾,完全人工控制弱光,长流水、自然水温培育,共产仔272万尾。布池后,根据不同日龄投喂轮虫、卤虫无节幼体、配饵和糠虾,控制光照,调节水质,防病治病,及时疏稀,420m~3水体育出平均全长28.8mm的黑苗77.6万尾,总成活率30％。认为,全人工控制光源蓄养亲鱼,溢水法布池,夜间开灯少量投饵,效果较好。     

"浦江一号"团头鲂与普通团头鲂亲本繁殖力及鱼苗培育对比试验

“浦江一号”团头鲂与普通团头鲂进行亲本繁殖及鱼苗培育的对比试验结果表明:“浦江一号”团头鲂相对产卵量为普通团头鲂的1．3倍,催产率、受精率、出苗率分别比普通团头鲂的高10．8％、5．2％、12．0％。经过一个月的培育,“浦江一号”团头鲂鱼苗平均成活率、平均体重分别比普通团头鲂高6．9％、20．9％。     

天津大银鱼仔、幼鱼的食性

１９９５年３月至５月对天津地区北塘、黄港二库、东丽水库的大银鱼仔、幼鱼的食性进行了分析研究。成鱼为肉食性鱼类,但在仔、幼鱼阶段主要摄食浮游生物中的原生动物,肠道中未找到枝角类,仔、幼鱼阶段的食性不是专一的,随水体中饵料生物组成的变化而变化。     

半滑舌鳎人工育苗技术研究

利用传统对虾育苗池,采用人工控温、生态调控育苗技术,成功培育出健康半滑舌鳎苗种,体色正常,育苗成活率37.5%。     

不同繁育方式蟹苗对1龄蟹种培育效果的影响

采用♀亲蟹平均规格分别为158.9g、132.8g,♂亲蟹平均规格为180g、150g两种群体繁育的蟹苗培育的1龄蟹种,其群体规格分别为128只/kg、160只/kg。在面积相同、放养密度相同、饲养条件相同的条件下,采用天然海水土池繁育的蟹苗培育的1龄蟹种成活率为5.1%、亩产蟹种8064只;而采用天然海水工厂化繁育的蟹苗,育种成活率为2.24%、亩产蟹种3609只;在蟹苗来源相同、饲养管理相同,培育池面积为19亩的培育池蟹种产量低于面积5亩的池塘。     

盐度对大银鱼受精卵孵化率的影响

进行了不同盐度对大银鱼受精卵孵化率的影响试验,结果表明,受精卵能够在２０以下盐度孵出仔鱼,但孵化率随盐度的升高而降低,孵出的仔鱼畸形随盐度的升高而升高,胚胎发育速度也相应减慢 。     

Effect of body colour of Oreochromis mossambicus (Peters) on predation by dragonfly nymphs

Abstract. Gold and black Oreochromis mossambicus (Peters) fry were stocked in 0.043-m³ hapas along with early instar dragonfly nymphs to determine the effect of body colour of the tilapia on vuinerability to predation by the insect. Hapas were stocked with either: 10 gold fry, 10 black fry and no dragonfly nymphs (10-10-0); 5 gold fry, 5 black fry and 2 dragonfly nymphs (5-5-2); 10 gold fry, 10 black fry and 2 dragonfly nymphs (10-10-2); or 10 gold fry, 10 black fry and 3 dragonfly nymphs (10-10-3). Four levels of predation were assessed: no predation, 1 dragonfly nymph per 5 fish, 1 per 6.7 fish, and 1 per 10 fish. Hapas were censused daily for 14 days. Fish that had been eaten were replaced with similar-sized fish to restore stocking densities. Average daily predation rate ranged from 0.24 to 3.0 and averaged 1.94 fry/dragonfly nymph/day. Average daily predation rates for all treatments were significantly (P = 0.05) different and were a function of both dragonfly and fish stocking rates. Dragonfly nymphs ate significantly more black fish than gold fish in the 10-10-2 and 10-10-3 treatments: overall (10-10-2, 10-10-3 and 5-5-2 treatments combined), dragonfly nymphs ate significantly more black (324) than gold (245) tilapia. Results from this study indicate that the bright body colour of the gold tilapia does not increase rate of predation by dragonfly nymphs.     

大西洋牙鲆雄鱼与漠斑牙鲆雌鱼杂交的初步研究

从山东引进全长3-5cm的美国大西洋牙鲆和漠斑牙鲆幼鱼到宁德市飞鸾镇海鑫育苗场,经2年6个月养殖后,从养殖群体中挑选出大西洋牙鲆雄鱼为父本,漠斑牙鲆雌鱼2为母本,在生殖季节通过埋植激素和人工调控环境条件催熟亲鱼,采用人工受精方法,获得杂交受精卵478．6g,受精率为62．9％,孵化率为75．3％,获得初孵仔鱼36万尾。经过65d的培育,育出平均全长4．20cm的杂交鱼苗22万尾,育苗成活率61．1％。鱼苗生长迅速,初步表现出杂交子代的优势性状。     

Effects of stocking density and feeding levels on growth and feed efficiency of Nile tilapia (Oreochromis niloticus L.) fry

The effects of stocking density and feeding levels on larval survival, growth rates, feed utilization efficiency and body composition of Nile tilapia (Oreochromis niloticus L.) fry were investigated in two consecutive experiments. In experiment 1, swimup fry (0.016 g average body weight) were stocked in 20‐L fibreglass tanks, in a closed, recirculating indoor system, at five stocking densities (3, 5, 10, 15 and 20 fry L^?1) and fed a larval test diet (40% crude protein) to apparent satiation, three times a day, for 40 days. Fish survival, percentage weight gain and specific growth rate (% SGR) were negatively correlated with stocking density. The best performance was achieved at 3 fry L^?1. However, no significant differences in growth parameters were found between 3 and 5 fry L^?1. Body composition was not significantly affected by stocking density. In experiment 2, fry (0.016 g average body weight) were stocked at 5 fry L^?1, and fed a larval test diet (40% crude protein) at six feeding levels (10%, 20%, 25%, 30% and 35% BW day^?1) and to satiation, three times a day for 40 days. Fish growth rates and survival were extremely poor at 10% feeding level, and improved significantly with increasing feeding levels up to 30%, and levelled off with further increase in feeding levels. On the contrary, feed conversion ratio (FCR) and protein production value (PPV) were negatively correlated with feeding level. The lowest feeding level (10%) produced significantly lower body lipid and higher protein and ash than other feeding levels. The present results suggest that the optimum stocking density and feeding level of Nile tilapia fry are 5 fry L^?1 and 30% per day respectively.     

What can we learn by studying dead fish fry?

This study investigated the influence of temperature (4, 8 and 12°C) on development and survival of brown trout (Salmo trutta) fry. The three aims of this study were: (a) to propose a typology of malformations; (b) to compare malformation types between live and dead fry and (c) to establish relationships between temperature and malformation occurrences. It was found 20 single malformations and 39 combinations of two or more malformations. Comparison between dead and live fry at different development stages (hatching, emergence and first food intake) showed that malformations of yolk sac were predominant at hatching and then decreased, while malformations of skeleton or multiple malformations were higher thereafter. All dead fry, and only 14% of live fry were malformed. Dead fry were mainly characterized by yolk sac malformations and multiple malformations whatever the temperature. Live fry showed a higher rate of skeleton malformations at 12°C, and the different types of malformations were equally represented at two other temperatures (4 and 8°C). To conclude, it is suggested that some malformations (yolk sac at hatching, yolk sac associated with skeleton malformations at emergence and skeleton at first food intake or combinations of malformations at all stages)might be lethal as they were founding dead fry and that temperature influences differently the occurrence of malformations.