匙吻鲟置换鳙鱼,养殖效益高

匙吻鲟是一种以摄食浮游动物为主的杂食性鱼类,集营养价值、药用价值和观赏性于一身,食性及生活环境与我国的鳙鱼相似,但其经济价值和社会价值都比鳙鱼高出许多倍,其推广价值更高。我国自1990年引进美国匙吻鲟后,2002年在湖北仙桃用自行培育养殖的匙吻鲟亲鱼人工繁育试验成功,标志着我国匙吻鲟苗种供应问题有望得到解决。经过水产养殖工作者多年的技术攻关和多方面的努力,到目前匙吻鲟的人工繁育技术渐趋成熟,为大面积的推广养殖这一优良品种提供了可能,也为大面积的匙吻鲟置换鳙鱼养殖打好了基础。我们在2009-2010年对响水坝水库用匙吻鲟置换鳙鱼进行养殖试验获得预期的养殖效果,在没有增加任何投入的情况下养殖效益明显,这一模式值得总结推广。     

匙吻鲟苗种培育常见疾病与防治措施

近年来,我国许多地区已开展匙吻鲟的养殖生产,基本掌握了其发眼卵的人工孵化、苗种培育和成鱼养殖等技术。而我所经过对匙吻鲟苗种5年的池塘培育试验实践认为,苗种培育是匙吻鲟成鱼养殖的一个关键点,其培育结果会直接影响商品生产的质量和效益。要培育     

匙吻鲟生物学及其生长的研究

通过对匙吻鲟生物学及其生长的研究,了解该鱼的形态特征、摄食习性及生长情况,结果表明:匙吻鲟是适合高寒地区养殖的名优品种,当年可达到500 g以上。     

匙吻鲟仔幼鱼培育技术

匙吻鲟 (Ｐｏｌｙｏｄｏｎｓｐａｔｈｕｌａ)隶属于匙吻鲟科 (Ｐｏｌｙｏｄｏｎｔｉｄａｅ) ,主要分布于美国中部和北部的大型河流及其附属的水域。是大型的淡水经济鱼类 ,适应性强 ,生长迅速 ,以摄食浮游动物为主。其卵、肉具有极高的食用价值和经济价值 ,独特的长吻体型又使其具较高的观赏性。我国于 1 990年开始从美国引进匙吻鲟 ,经过十年的养殖 ,积累了一些经验[1～ 4] 。匙吻鲟的苗种培育一般采用在池塘原池培育浮游动物或在水泥中投喂浮游动物[2 ] 的两种方式进行 ,有关用人工饵料培育匙吻鲟仔幼鱼的方式则鲜见报导。笔者于今年 5月…     

匙吻鲟亲鱼培育及人工繁殖技术

匙吻鲟(Polyodon spathula Walbaum)隶属于匙吻鲟科,是世界上现存2种匙吻鲟科鱼类之一.匙吻鲟主要分布于美国中部和北部的大型河流、湖泊及水库海湾沿岸地带,是美国特有的大型经济鱼类,体重最大可达40 kg.匙吻鲟集食用、观赏和药用于一身,肉鲜味美,具有极高的经济和观赏价值,适宜于观赏、垂钓和食用,是池塘,尤其是湖泊、水库养殖的优良品种[J].匙吻鲟引进国内后受到广泛关注,尤其是在水产养殖品种结构调整,提高大、中型水面养鱼效益方面.通过该项目的实施,提高匙吻鲟亲鱼培育和人工繁殖效果,为大面积推广匙吻鲟养殖提供了良好的条件.     

匙吻鲟苗种高密度培育初探

近几年来，匙吻鲟的养殖已遍布全国各地，成为国内规模化养殖的又一新宠。然而，由于匙吻鲟在仔幼鲟培育技术上有其种的特异性，其苗种培育的成活率还较低。当前，如何提高其成活率已是匙吻鲟养殖工作的关键，基于此，我们参照国内匙吻鲟培苗的各种方法并在福建省淡水水产研究所几年来鲟鱼养殖实践的基础上，进行了较高密度的培苗试验，以期寻求一条较佳的培苗技术路线，既提高匙吻鲟的培苗成活率又能保证苗种培育的放养密度。     

池塘培育匙吻鲟鱼种技术总结

匙吻鲟（Polyodonspathula）原产北美洲，属鲟形目、匙吻鲟科，是世上仅存的两种匙吻鲟科鱼类之一。它摄食浮游生物，与我国鲢鳙鱼食性相同，是一种大型淡水鱼类。由于它具有适应性强、生长迅速和经济价值高等特点，自我国1988年首次从美国引进以来，一直受到水产科技工作者的重视。目前，国内养殖匙吻鲟的单位逐渐增多。匙吻鲟鱼种是匙吻鲟养殖的重要一环，国内报道很少。作者于1999年开展了池塘培育匙吻弱鱼种的工作，现作一总结报道。l鱼种放养池塘面积为0‘43Inn’，1999年5月ZI日放养匙吻婚鱼种1940尾，其平均全长为8．6cm，平均体重…     

安康地区利用家鱼产卵池培育匙吻鲟苗种技术研究

匙吻鲟（Polyodon spathula）又称匙吻白鲟、鸭嘴鲟,属鲟形目、匙吻鲟科,是原产于美国密西西比河和密苏里河流域的一种古老的大型淡水经济鱼类。其适应性强、生长迅速,以摄食浮游动物为主。匙吻鲟的卵、肉具有极高的食用价值和经济价值,独特的长吻体型又使其具有较高的观赏性。上世纪60年代匙吻鲟人工繁殖的成功使得匙吻鲟的人工养殖成为可能。我国南方省份于上世纪80年代开始引进,采用包括池塘和网箱养殖等不同方式进行养殖。匙吻鲟繁殖周期长,苗种价格昂贵,     

生态培育匙吻鲟鱼苗试验

本实验是将过滤后的养成鱼池上层水做为培育匙吻鲟鱼苗的水源,采用纯氧放苗技术培育匙吻鲟苗,养殖过程适时补充瓶装纯氧.结果表明:50000尾匙吻鲟水花苗(体长7mm～9mm),经22天培育,共出池5cm左右苗种39999尾,培苗存活率达到80.0%.     

延迟投饵对匙吻鲟仔鱼存活与生长的影响

在（22±0.5）℃水温条件下,通过饥饿试验,研究了延迟投饵对匙吻鲟（Polyodon spathula）仔鱼存活与生长的影响。结果表明：延迟1~2 d投饵对仔鱼存活的影响不显著;延迟3 d以上投饵,仔鱼成活率显著下降;完全饥饿条件下,仔鱼半致死时间为11日龄,全部死亡时间为17日龄;延迟1 d投饵对仔鱼生长的影响不显著,延迟2 d以上投饵对仔鱼生长的影响显著。匙吻鲟仔鱼开口摄食期没有混合营养期,从初次开口摄食到饥饿半致死之间的间隔仅4 d。因此,匙吻鲟仔鱼初次投喂的最适时间建议在开口摄食后的2 d之内。     

Effects of Calcium and Magnesium Hardness of Incubation Waters on the Hatching Success of Hybrid Eggs of ♀ Channel Catfish,Ictalurus punctatus × ♂ Blue Catfish,Ictalurus furcatus

Hatching efficiency is generally lower in channel catfish, Ictalurus punctatus × blue catfish, Ictalurus furcatus, hybrid catfish hatcheries compared to hatcheries hatching pond‐spawned channel catfish eggs. Egg quality and hatching water hardness are known variables influencing the efficiency of hybrid catfish fry production in hatcheries. Previous research recommended that at least 60 mg/L hardness had to be contributed only by calcium to optimize the hatching success of hybrid catfish eggs. However, whether the effect of waterborne magnesium in hatching waters facilitates or impedes the hatching success of hybrid catfish is not known. Two trials were conducted to determine the effects of calcium alone or magnesium hardness, in combination with the hatching success of hybrid catfish eggs. Trial 1 showed that if the previously identified minimum hardness criterion of 60 mg/L was met by calcium in the hatching waters, added magnesium had no effect on the hatching success of hybrid catfish eggs. Trial 2 showed that the previously identified minimum hardness of 60 mg/L can be met by either calcium alone or magnesium replacing up to 50% of the total hardness in the hatchery waters for optimal hatching success of hybrid catfish eggs. Calcium provides a specific requirement during embryonic development of catfish. The results from this study can be used to design treatment processes for hatchery water supplies to improve efficiency of hybrid catfish fry production in hatcheries.     

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.     

美洲鲥仔、稚、幼鱼的形态发育与生长特征

通过对美洲鲥(Alosa sapidissima)仔、稚、幼各发育期的连续取样,系统观察了仔、稚、幼各期的形态变化及生长发育特征.结果显示:在水温(20±1)℃下,初孵仔鱼全长(6.75±0.60)mm;2日龄仔鱼即开口摄食,进入混合营养期;4 日龄仔鱼卵黄囊吸收完毕进人晚期仔鱼阶段,完全依靠外源物质获取能量,主要以鳔室、脊椎形成及各鳍的分化与形成为主要标志;培育至36 d,仔鱼鳃盖后缘及脊椎骨两侧线有少量鳞片状突起,标志美洲鲥结束仔鱼期进入稚鱼期;培育至65 d,仔鱼身上鳞片基本长出,腹膜闭合,美洲鲥完成变态成为幼鱼.仔鱼培育期间,除了严格控制培育水温在(20±1)℃外,2日龄仔鱼开口后就应及时投喂轮虫类开口饵料,密度为5～10 ind/mL,这是苗种培育中不可忽视的重要环节.稚鱼期间在主食枝角类、桡足类的同时进行驯食.本实验采用特制缓沉饲料及时驯化转食再过渡到伞部摄食人工浮性膨化颗粒饲料,驯食时间为21 d,驯食是成功进行人工池塘养殖的关键所在.本研究旨在探讨提高美洲鲥早期培育过程中的成活率及成功进行池塘养殖的可行性.     

黑鲪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３００ｍ３育苗水体中，育出２６．７ｍｍ以上黑鲪鱼苗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。     

Effects of Environmental Sodium Chloride on Percent Hatch, Yolk Utilization, and Survival of Channel Catfish Fry

Abstract.— Only limited research has addressed the effect of salinity on hatching of channel catfish Ictalurus punctatus eggs, and no studies have evaluated the effect of salinity on fry development and survival. This study was undertaken to determine the effect of environmental sodium chloride (0, 1, 2, and 4 g/L. NaCl) on percent hatch, yolk utilization, and survival of channel catfish fry. Experiments were conducted in recirculating systems using seven egg masses (1–2 d old). Each egg mass was divided into smaller portions which remained undissociated or were dissociated with sodium sulfite (NaSO₃). Eggs were incubated until hatching. Wet and dry weights were obtained for sacfry at 1 and 5 d post-hatch to determine wet weight gain and dry weight loss, and fry were sampled 7 d after initiation of exogenous feeding to determine survival. Percent hatch, yolk utilization, and survival of fry hatched from undissociated eggs were greatest at 1 g/L NaCl. In addition, treatment of eggs with NaSO₃ significantly reduced percent hatch at all NaCl levels. Although our results indicate that addition of NaCI to hatchery water supplies can increase production of channel catfish fry, additional research is needed before this practice can be recommended on a commercial basis.     

Influence of egg size on the growth,onset of feeding,point-of-no-return,and survival of unfed Oreochromis mossambicus fry

The variation in egg size within and between egg clutches of O. mossambicus, and the subsequent influence of mean egg size on growth, feeding incidence and survival of unfed fry were investigated.The individual egg sizes within 90% of the egg clutches examined were normally distributed and the coefficient of variation of egg size within clutches ranged from 7.4% to 15.4%. Fry emerging from the small, medium and large egg size groups reached their maximum length and weight at 9, 9 and 12 days after hatching, respectively. Maximum attainable fry length and weight were significantly correlated with egg size (r = 0.885 and 0.947, respectively, with P < 0.01).Egg size had little influence on the onset of feeding. Fry were capable of exogenous feeding within 6 to 7 days of hatching. Fry originating from small and medium egg size classes reached the point-of-no-return at 15–16 days after hatching compared to 21 days for fry from the large egg size class. The mean survival time (ST₅₀) of fry on their yolk reserves was significantly correlated (r = 0.923; P < 0.01) with their original mean egg weight and ranged from 9.5 days for fry hatching from 0.91-mg eggs to 21 days for fry from 1.93-mg eggs.     

齐口裂腹鱼的人工繁殖与苗种培育

流水培育齐口裂腹鱼,选择3龄以上雌雄亲鱼各60尾,使用绒毛膜促性腺激素、促黄体素释放激素A2和地欧酮3种药物混合对雌鱼进行注射催产,催产率为85%,受精率为79%,适宜催产的水温为9～16℃;在14～16℃的水温条件下,受精卵在202h内全部出膜,孵出仔鱼约61万尾,孵化率为80%。对孵出的61万尾仔鱼进行了逾90d的培养,共计出塘45万尾,成活率约为74%。试验结果表明,人工培育的齐口裂腹鱼亲鱼性腺能够发育成熟,经催产能成功繁殖。     

杂交鳢人工繁殖和苗种培育技术研究

本文研究了杂交鳢(Channa maculate♀×C.argus♂)的亲鱼斑鳢(C.maculata)培育、杂交鳢人工繁殖、孵化和鱼苗培育等技术。结果显示:斑鳢在杭州地区池塘条件下经人工培育可达性成熟,但无法在自然条件下过冬,需进行保温越冬。杂交鳢人工催产繁殖的适宜水温在22℃以上,以25～28℃为宜。25～30℃水温条件下,分二次注射LHRH-A2、HCG和DOM混合催产剂,其效应时间在32 h以内;采用自然受精,泡沫箱或网箱孵化,其平均催产率为93.3%,平均受精率为72.9%,孵化率为64.1%,孵化时间18～45 h;通过定时过筛、分级分养、适时驯食等技术培育20 d左右,鱼种全长可达3.3～3.8 cm,平均成活率56.5%。     

Effects of salinity on growth and mortality of migratory and resident forms of Eurasian perch in the Baltic Sea

Abstract – In the coastal areas of the Baltic Sea, there are two forms of perch (Perca fluviatilis). One of the forms is migratory and spawns in streams entering the Baltic Sea. The other form is resident and spawns in brackish water. Both forms utilise the coastal habitat for foraging. We examined the spawning success of the two forms in fresh and brackish water (7‰, equal to salinity in the south Baltic Sea). The experiments showed that hatching success was equally high in freshwater and in brackish water despite female origin. The survival of yellow‐sac and free swimming fry was significantly reduced in brackish water, which was independent if the fish was of migratory or brackish resident origin. Further, growth rate of perch fry was severely reduced in brackish water. The results indicate that perch has not developed any tolerance to brackish water in the young life stages. The migratory life strategy of perch can thus be explained by higher survival of fry in freshwater.     

Accumulation of aluminum on atlantic salmon eggs during the incubation period

Groups of rainbow trout Onchorhyncus mykiss eggs were incubated in duplicate trays with PVC screens and the original aluminum screens. During the incubation period, aluminum bound to sediments was deposited on the eggs and in the whole hatching system.

The pH of the inlet water to the hatching system with PVC screen was experimentally lowered by adding sulphuric acid. Buffering of the outlet water was observed at pH lower than 5, and at pH 4·5 and lower, an increased aluminum concentration in the outlet water was recorded.

These experiments show that aluminum accumulated on eggs and in the hatching system during periods with neutral water represents a serious threat to the survival of eggs and fry of salmonids if pH drops below 5·0, even for a few hours. In sensitive lakes and rivers, pH drops below 5·0 are common during heavy rain or during the snow melting period.