鲟鱼苗种培育阶段气泡病的危害与防治

随着北京地区鲟鱼养殖规模不断扩大,当地对鲟鱼苗种的需求量也越来越大。养殖条件好的养殖户由鲟鱼仔鱼阶段开始进行鲟鱼苗种培育。在鲟鱼苗种培育阶段要经过仔鱼开口摄食和仔鱼转口摄食两个敏感时期。这两个时期是鲟鱼苗种培育成功与否的关键环节。由于鲟鱼仔鱼特殊的生理结构和生活习性,常常会因多种原因导致气泡病的发生,往往造成程度不同的损失,甚至造成大批量死鱼现象。笔者现将鲟鱼苗种培育阶段气泡病防治方面的一些经验和体会总结如下。     

鲟鱼常见病的治疗

我国鲟鱼养殖是近二三年发展起来的新项目，由于它的发展前景广阔，近年来投资鲟鱼养殖的人越来越多。但有关鲟鱼养殖的技术病害防治和鲟鱼对一些常用药物的敏感性等方面的报道却还少见，在养殖过程中遇到这方面的情况时却只能借以往的经验技术来处理，对所采取措施的有效性和安全性都缺乏依据和信心。如果一旦病情判断错误或用药失误，不但错过了治疗时机，还有可能造成很大损失。所以，借此本人就杂交鲟鱼、俄罗斯鲟鱼等在幼鱼阶段的几种常见病及治疗处理的一些措施和经验同大家交流。一、气泡病1．症状：发病时，鱼游动缓慢、无力、上浮…     

人工养殖鲟鱼中的疾病与防治

鲟鱼抗病能力较强,发病率较低,但由于其骨板坚硬,鳃部分裸露,在人工环境下进行高密度养殖,相互磨伤而容易受到病虫害的感染.鲟鱼患病后用普通药物难以治愈,且鲟鱼对一般的常用药物非常敏感,这要求我们在鲟鱼养殖工作中,加强鱼病预防工作,方可将损失降到最低点.鲟鱼类的商品养殖在国内才刚刚起步,有关其病害研究资料极少.已报道的鲟鱼类主要寄生性疾病有水霉病、肠炎病、肿嘴病和寄生虫病等,非寄生性鱼病有气泡病、氨氮中毒等,在此将鲟鱼疾病及其防治方法作以介绍,仅供大家参考.     

中国对虾气泡病成因机制

中国对虾气泡病成因机制中国科学院海洋研究所虾病专家张乃禹近几年对中国对虾气泡病成因及防治方法进行了研究，张乃禹通过实验，对中国对虾气泡病成因机制研究获得了较理想的结果，他认为，水温突然升高使水中溶解气体过饱和是导致对虾气泡病的必不可少的重要条件，但不...     

獾子洞水库冬季鱼类气泡病观察

鱼类气泡病是一种非寄生性鱼病，七十年代前发现主要危害鱼苗鱼种。七十年代以来，我国陆续有过金鱼尾鳍皮下气泡病、冰下亲鱼气泡病和池塘成鱼气泡病的报道。作者之一曾观察到火力发电厂温流水养鱼水域莫桑比克罗非鱼和尼罗罗非鱼成鱼、亲鱼气泡病。日本也有过鲑、鳟鱼气泡病的报道。至于大型水域越冬鱼类气泡病的报道，在国内外实属罕见。     

谈鱼类气泡病

我国鱼类的气泡病是普遍存在和经常发生的。但由于研究手段的落后，对其病症和机理认识不清，故不为养鱼界重视，至今还有人认为鱼苗的气泡病是误吞气泡造成的。现将笔者所经历的鱼类气泡病及对此病的机理与防治方法的认识叙述如下，供同行批评、指正。一、我所见到的气泡病1．     

也谈鱼类气泡病

鱼类气泡病是鱼苗培育阶段常见的、危害性较大的鱼病之一。特别是鱼苗下塘后数天内，阴雨转晴的天常有发生。此病一旦发生，可见鱼池下风处的水面上飘浮着鱼苗尸体和病苗。由于鱼类气泡病发病突然，病期短，井难于发现。因此对其深入研究甚少，并有多种说法。如有人认为“鱼苗气泡病是鱼苗误香水中小气泡而引起的”。史为良先生认为鱼类气泡病是鱼鳃吸取水中溶解的气泡，堵塞其血管造成鱼类死亡。笔者在实地与治疗观察中发现，其情况又别于上述两种说法。１鱼苗气泡病致病途径笔者于１９６８年５月上旬久雨转晴的一个早晨巡塘，发现下塘２天…     

还谈鱼类气泡病

鱼类气泡病是鱼苗培育的常见病，其发病突然、病程短，发病率和死亡率都可达１００％，可见危害性很大。１９９８年第６期和第１２期《科学养鱼》上分别发表了两篇关于鱼类气泡病的文章，其所见有相同之处，也有不同之处，现将我所观察到的气泡病的发病条件及原因、病理及...     

我国鲟鱼繁殖和养殖技术研究

鲟鱼因其天然的高贵品质和食用价值，无论在国内还是国际市场都是极为珍贵的水产品。20世纪70年代以来，国内外对鲟鱼研究的重点逐渐转向人工养殖。许多国家开始了鲟鱼的相关研究和商业性生产。近年来，鲟鱼养殖热不断升温，目前，鲟鱼的养殖已成为我国淡水养殖中的一个热点。在我国最具养殖意义的纯种鲟鱼为5种，     

鲟鱼卵甲藻病的初报

本首次对鲟鱼卵甲藻病作了报道，章对该病病症进行描述，初步分析了鲟鱼卵甲藻病病因，并提出了防治鲟鱼此病的几点见议。     

史氏鲟南移驯养及生物学的研究:Ⅲ.仔鱼的开口摄食

用单一的水蚯蚓、卤虫无节幼体、池塘浮游动物、人工配合饲料投喂及先卤虫无节幼体后人工配合饲料混合投喂等五种方式培育史氏鲟仔鱼。结果为：卤虫无节幼体是史氏鲟最好的开口饵料,可获得高的成活率和生长率;开口摄食后３－５天,即可开始投喂人工饵料进行食性驯化,２０日龄的鱼苗可获得满意的饵料驯化效果。     

配合饲料饲养史氏鲟(AcipenserSchrencki)幼鱼的试验研究

经人工孵化的同亲本史氏鲟鱼苗，用水蚯蚓饲养20天后，直接转入水簇箱内（水体100×25×40cm）进行配合饲料饲养试验。试验设3个不同蛋白质梯度的配合饲料组（1号料、2号料、3号料）和一个投喂水蚯蚓的对照组，每组放鱼100尾，试验期为30天，30天后试验各组幼鲟体重分别为5．01g、4.74g、4.91g和4．08g。存活率分别为82％、86％、75％和95％。试验结果表明：用活饵喂养一段时间的史氏鲟幼鱼仍可直接采用配合饲料喂养，无需进行过渡驯饲，同时指出适合于幼鲟营养平衡的配合饲料仍需进一步改进与提高.     

史氏鲟南移驯养及生物学的研究:Ⅱ.几种环境因子对仔鱼的影响

非离子氨对史氏鲟早期仔鱼７２和９６小时的ＬＣ５０分别为０６８和０６３ｍｇ／Ｌ；对晚期仔鱼的８、１２、１４、４８、７２和９６小时的ＬＣ５０分别为０５０、０４３、０３５、０２６、０２１和０１７ｍｇ／Ｌ，当浓度达到０３５ｍｇ／Ｌ时，在１７小时内造成试验鱼全部死亡。４８小时内造成早期仔鱼５０％死亡的总铁浓度为５００ｍｇ／Ｌ。史氏鲟仔鱼对ｐＨ忍耐性的上限和下限分别为９２５和３６０，立刻致死的ｐＨ值分别为２０９—２５０和１０１０—１０００。     

Larval lake sturgeon production and drift behaviour in the Menominee and Oconto Rivers,Wisconsin

Lake sturgeon (Acipenser fulvescens) have been negatively impacted by barriers to migration, pollution and overharvest. Biological data such as the timing of spawning activity and larval drift have provided a better understanding of larval production success or failure on a site-specific basis. However, many river systems that serve as reproductive locations for remnant lake sturgeon populations remain understudied. The objective of this study was to compare and contrast aspects of larval lake sturgeon drift within and between the Oconto and Menominee Rivers over multiple reproductive seasons. Differences in larval drift chronology, the size of drifting larvae during the season and the cross-sectional profile of drifting individuals as a function of river velocity were evaluated. D-frame drift nets were deployed at a single transect below spawning sites in the Menominee (2012, 2013 and 2014) and Oconto Rivers (2013, 2014 and 2015). A total of 4,442 larvae were captured across all seasons. Larvae exhibited nonrandom drift profiles related to water velocity, and larvae size was related to horizontal drift location. The seasonal increase in body size of drifting larvae also differed among drift events within and between years and across rivers. This information will provide a better understanding of lake sturgeon early life history and has practical management connections including spawning site protection/enhancement and river flow mitigation.     

Comparative behaviour and dietary effects in early life phases of American sturgeons

Experiments were conducted with the larvae and early juveniles of three species of sturgeon to determine effects of diet and development on swimming and foraging behaviour as well as depth distribution in 100-L aquaria. About 500 hatchlings were placed in each tank with two or three replicates of three or six diet treatments, including live and dry feeds. Eight types of swimming or foraging activity were recorded with a lap-top event recorder and with fish counts in three depths of water. Analysis of variance showed live diets resulted in greater foraging activity in upper water horizons than most dry diets for Atlantic sturgeon, Acipenser oxyrhynchus Mitchill. Scouring, a foraging activity, differed among diet types in early juvenile lake sturgeon, A . fulvescens Rafinesque. Developmental effects included early peaks in the performance of swim-up for all species and swim near surface for two of three species. Postlarvae (post-yolk-sac larvae) of shovelnose, Scaphirhynchus platorhynchus (Rafinesque), and Atlantic sturgeon swam inverted, an apparent foraging tactic associated with elevated or air-water surfaces. Postlarvae maintained (lake sturgeon) or shifted to (other species) bottom swimming with increased scouring activity. Shovelnose early postlarvae occupied higher average water-column heights than lake or Atlantic sturgeon. Shovelnose (only species tested) postlarvae showed greater activity in upper water horizons at night. These results suggest a fundamental shift to benthic foraging during the postlarval phase, with shovelnose sturgeon continuing to forage in suprabenthic zones to a greater degree than the other two species.     

用配合饲料驯饲中华鲟仔鱼研究初报

按前7天投喂活饵（水蚯蚓），后期投喂配合饲料和直接投喂配合饲料两种方式对中华鲟仔鱼进行驯饲，试验结果表明，这两种驯饲方式均获得了一定的驯饲成功率，但以第一种方式驯饲效果较好。驯饲效果主要取决于饲料的营养质量和适口性。     

The effects of salinity on the fertilization rate and rearing of the Persian sturgeon (Acipenser persicus) larvae

Persian sturgeon eggs were fertilized with different levels of salinities (0.5, 2, 4, 6, 8, 10, 12?ppt), and then each group was incubated in the same salinity until hatch. The fertility (%), hatching rate as well as larvae cumulative mortality rate and abnormality (%) were measured. Our Results revealed that Persian surgeon eggs could be fertilized in the different salinity concentrations but not more than 4?ppt. Moreover, hatching rate decreased with increase in salinities more than 2 and 4?ppt, respectively, and no larvae hatched in 6?ppt salinity. According to these results, the salinity tolerance threshold for Persian sturgeon larvae hatching in brackish water is less than 4?ppt.     

Change in Sox9 protein localization through gonad development in Russian sturgeon (Acipenser gueldenstaedtii)

The Russian sturgeon is a highly prized species reared in aquaculture. The process of gonad development in this critically endangered species is poorly understood. The aim of this study was to describe the localization of Sox9 protein during gonad development of the Russian sturgeon from the day of hatching to the 1440 day post hatching (dph). The larvae at age 1, 10, 25 dph and prepared gonads of 300, 720, 1440 dph individuals were immunohistochemistry‐stained for Sox9 detection. Sox9‐positive regions were detected in larvae in primordial germ cells cytoplasm. Analysis of 300 dph sturgeon gonads revealed the presence of the Sox9 protein in cytoplasm of some oocytes in the chromatin nucleus stage. In testes at 720 dph, Sox9 was observed in the cytoplasm of type A and early B spermatogonias. In the ovaries, Sox9 was observed in the cytoplasm of diplotene oocytes and prefollicular cells. In testes of 1440 dph sturgeon, Sox9 was present in the nucleus of the spermatocytes and in types A and B spermatogonias cytoplasm. Analysis of ovaries at 1440 dph reveals multiple diplotene oocytes with a Sox9‐positive cytoplasm. Furthermore, in 720 and 1440 dph, sturgeon presence of intersexual gonads was detected. In intersex gonads, Sox9 was observed in the cytoplasm of diplotene oocytes and type A spermatogonias. This study may be the first attempt to determine Sox9 protein localization during ontogenesis of the Russian sturgeon. Localization of Sox9 protein may become a useful marker of the maturation level in testis of the Russian sturgeon.     

Whole-body concentrations of cortisol and sex steroids in white sturgeon (Acipenser transmontanus, Richardson 1836) during early development and stress response

In general little is known about hormones and the ontogeny of the stress response in the early developmental stages of chondrostean fishes and in particular of white sturgeon (Acipenser transmontanus, Richardson 1836). In this study, we measured for the first time cortisol and sex steroids (testosterone and estradiol) in eggs, larvae, post-larvae, and fry of white sturgeon by radioimmunoassay (RIA), to elucidate some endocrine aspects of its development. The cortisol, testosterone, and 17β-estradiol of maternal origin found in unfertilized eggs of white sturgeon probably regulate both growth and development of the embryo. Cortisol decreased after fertilization, whereas testosterone and 17β-estradiol did not significantly change. During the late stages of embryo development and immediately after hatching, endogenous production of cortisol and sexual steroids, respectively, occurred. Sex steroids may be physiological inducers of gonad sex differentiation in sturgeon. All steroids showed an increase 10 days post-hatch (dph), near the transition from an endogenous to an exogenous energy source. Cortisol maintained the same basal levels even after metamorphosis, whereas testosterone and 17β-estradiol declined significantly in post-larvae at 35 and 45 days post-hatch. In addition, to evaluate the ontogeny of a functional hypothalamic-pituitary-interrenal (HPI) axis, larvae and fry were submitted to acute stress. The HPI axis did not seem to be functional on the first day post-hatch, but became so from the third day post-hatch onward.