水质性鱼病的防治

1．皮肤充血病发病原因：引起此病的主要原因是鱼体长期缺乏光照，水质不良或频繁换水。此病多在阴雨季节发生。若不及时治疗，轻者影响食欲，重者死亡。防治方法：①加强光照，降低水位或提高水温，可抑制此病的蔓延。②在10k水中溶解1～2g呋喃西林，浸洗病鱼10—30min。③用3％-5％的浓盐水，浸洗病鱼10～15min。     

抓好夏秋之交水产养殖病害防治

鱼类发病与气候、水温有着密切的关系，尤其在夏秋之交（８～９月份），此时水温适宜，鱼类摄食旺盛，生长快速，因该季节昼夜温差较大，鱼体抗病能力相对较弱，致病微生物极易繁殖，是鱼、蟹等养殖动物疾病流行的主要季节，必须十分注意疾病的防治工作。一、细菌性烂鳃病【病原体】柱状屈桡杆菌，菌体细长，大小为０．５微米×４～４８微米。主要危害青鱼、草鱼。【症状】病鱼体色发黑，尤以头部为甚。病鱼游动缓慢，呼吸困难，食欲减退。病鱼鳃盖内表面的皮肤充血发炎，中间部分常糜烂成一圆形或不规则的透明小窗，俗称“开天窗”；鳃上粘…     

黄姑鱼五种常见病害的防治

1 烂鳃病此病多发在5-8月、水温25～30．5℃,危害程度达到5％～10％。病鱼体色发黑,游动缓慢,外界刺激反应迟钝,呼吸困难,食欲减退,鱼体消瘦。病鱼鳃盖内表皮充血发炎,鳃上淡黄色黏液多,鳃丝肿胀部分呈淡红色,并可见小出血点。防治措施:用漂白粉先溶于水中,滤掉残渣,制成浸泡消毒水,浓度为10×10-6。将网箱内的鱼全部浸泡 3-5分钟,然后移到10-20×10-6浓度的呋喃西林水溶     

草鱼烂鳃病的防治方法

生石灰防治细菌性烂鳃病是危害当年草鱼种和成鱼的严重病害之一。每年4—10月为流行季节,水温超过30℃时,发病率较高,死亡也较严重。烂鳃病是由一种粘球菌侵入鱼的鳃部引起的。病鱼消瘦,体色变黑,头部尤为乌黑,离群独自在塘边慢游,     

鱼种消毒的几种方法

<正> 1 用5％的食盐水,在水温10～15℃时浸洗鱼体20min,能杀死鱼体身上的水霉、粘细茵,对预防细菌性烂腮、水霉病和一些寄生虫病有良好的作用。2 用15ppm的孔雀石绿溶液,在水温10～15℃时浸洗鱼体20～30min,可杀死鱼体身上的水霉菌、小瓜虫等,对预防水霉病和小瓜虫病等效果最好。     

淡水鱼类出血病成因浅析

淡水鱼类出血病主要分为细菌性出血病和病毒性出血病，细菌性出血病在发生频率和危害程度方面都远远高于病毒性出血病（如草鱼呼肠弧病毒出血病等），所以本文重点就淡水鱼类细菌性出血病作浅析。 淡水鱼类细菌性出血病又称为细菌性败血症和暴发性出血病等，是我国养鱼史上危害鱼种类最多、流行地区最广、流行季节最长、造成损失最大的一种急性传染病。其危害鱼类有鲤鱼、鲫鱼、团头鲂、鲢鱼、鳙鱼、草鱼、黄鳝等多种淡水鱼类，全国２０多个省、市、自治区流行此病，流行季节从２月底至１１月底，水温在 ９—３６℃之间，尤以水温在 ２８℃…     

鱼类细菌性败血症发病鱼池细菌数量及致病性气单胞菌的初步研究

本文对细菌性败血症发病鱼池细菌数量及气单胞菌的数量、溶血性及致病力进行了研究。结果表明:水温在28.5℃以下时,细菌数量与水温基本成正比,发病池与不发病池的细菌数量无显著性差异;水体中广泛存在气单胞菌,其占水体总菌量比例随水温的上升而升高;发病池及未发病池中均存在能产生hec毒素和不产生hec毒素的嗜水气单胞菌株,两者数量上无显著差异;水体中存在血清型为TPS—30及PBJS—76的嗜水气单胞菌,且大多数对鱼体有毒力,以5×10~7CFU/尾腹腔注射,可使试验鱼大部分或全部发病死亡。     

針虫病和鱼虱病并发症最新防治

针虫病和鱼虱病是常见的多发鱼病,尤其是在3—10月更为流行。这两种病对鲢、鳙、草鱼危害极为严重。从1992年开始,我们在江苏盐城市的义丰镇、大纵湖、北龙港、楼王、秦南等乡镇,积极推广使用溴氰菊酯(商品名称“敌杀死”)治疗针虫病和鱼虱病,取得了良好疗效,现简单介绍常用浸洗或全塘泼洒的方法,供养殖者参考。 1、浸洗法。鱼种发生针虫病和鱼虱病,多采用浸洗法。首先,用刮罟把鱼种集中赶入鱼种捆箱内,然后用水稀释溴氰菊酯,并泼入鱼种捆箱内,浸洗鱼种。浸洗时间,要看鱼种的忍受度而定,一般浸洗5—10分钟,但一旦发现鱼种异常,须     

放养鱼种宜消毒

鱼种消毒,是用各种药物配成各种药液,浸洗鱼种,杀灭鱼体上附着的或已经感染的细菌、寄生虫等病原体,预防鱼病的发生,这是提高放养鱼种成活率的一项有效措施。消毒所用药物有漂白粉、硫酸铜、高锰酸钾、食盐和晶体敌百虫等等。具体方法如下:1.漂白粉,配成药液的浓度为10PPM,即在每立方米水(重1,000公斤)中放入10克的漂白粉,水温在10—15℃,浸洗时间为20—30分钟;15—20C,浸洗15—20分钟。主要防治细菌性皮肤病、烂鳃病等。     

东北地区大宗淡水鱼出血病的流行病学调查

<正>淡水鱼出血病,又称"腹水病"或"细菌性败血症",是我国养鱼史上危害鱼种类最多、流行地区最广、流行季节最长、造成损失最大的一种急性传染病,其主要细菌性病原为致病性嗜水气单胞菌。该病几乎危害所有主养的淡水鱼类,且在各个地区均有广泛流行,死亡率可达50%~80%。临床发病鱼体表现为体表严重充血,眼眶周围充血,     

Atlantic Fisheries Technological Conference,Moncton, NB,August 21, 1995

No abstract available for this article.     

Anguilla huangi Teng, Lin, and Tzeng, 2009, is a junior synonym of Anguilla luzonensis Watanabe, Aoyama, and Tsukamoto, 2009

Anguilla luzonensis and A. huangi were each described in 2009 using eels obtained from northern Luzon Island. We examined the taxonomic status of these two groups of eels using morphological and molecular genetic characters. There were no significant differences in two vertebrae counts between eels of A. luzonensis and A. huangi. Mitochondrial 16S ribosomal RNA and cytochrome b genes sequences were obtained and compared among 28 specimens of A. luzonensis, the holotypes of A. luzonensis and A. huangi, and one specimen of the other 15 anguillid species. The specimens of A. luzonensis exhibited almost identical sequences, including the holotype, with only a few site differences, and the genetic difference between the holotypes of A. luzonensis and A. huangi was within the range of differences of specimens of A. luzonensis. The other anguillid species were genetically very different from A. luzonensis and A. huangi, although A. interioris is a closely related species. It is clear that A. luzonensis and A. huangi are the same species, and according to the principle of priority in zoological nomenclature, A. luzonensis Watanabe, Aoyama, and Tsukamoto, 2009 is the valid species name, and A. huangi Teng, Lin, and Tzeng, 2009 is a junior synonym of A. luzonensis.     

Surface disinfection of Pacific threadfin, Polydactylus sexfilis, and amberjack, Seriola rivoliana, eggs

The effects of exposing the eggs of Pacific threadfin and amberjack eggs (AEs) to different concentrations of hydrogen peroxide for 5 min on hatch rate and survival were assessed in a series of experiments using a petri dish model rearing system. Despite significant inter‐batch variation in hatch rate, it was shown that eggs of both species could be safely exposed to up to 11 340 mg L⁻¹ H₂O₂ for 5 min. Exposure to 34 230 mg L⁻¹ H₂O₂ for 5 min was shown to be lethal to AEs at a late stage of development. In two further experiments, it was demonstrated that Pacific threadfin eggs were resistant to all tested concentrations of a range of polyvinylpyrrolidone iodine (PVP‐I) concentrations and contact times (up to 1000 mg L⁻¹ PVP‐I for 10 min). The level of bacteria adhering to the eggs of both species was highly variable. Where eggs were heavily colonized (>10⁴ cfu egg⁻¹), hydrogen peroxide concentrations of at least 11 340 mg L⁻¹, or PVP‐I concentrations higher than 500 mg L⁻¹ for 10 min, were required for effective sterilization. In less colonized batches, rinsing in sterile seawater or exposure to lower (550 mg L⁻¹) concentrations of H₂O₂ was sufficient to result in high apparent levels of surface sterility (<1 cfu egg⁻¹).     

Age,growth, maturity and the overfishing of the iconic sciaenid,Argyrosomus japonicus,in south-eastern,Australia

Mulloway (Argyrosomus japonicus) occur in estuarine and coastal waters surrounding Australia, Africa, India, Pakistan, China, Korea and Japan, where they are important in fisheries. This study identified that mulloway in south-eastern Australia had similar growth rates, but matured at smaller lengths and younger ages, to those in South Africa and Western Australia. Growth of both sexes was similar to about 5 years, after which females grew faster and attained a greater maximum length than males. Female mulloway matured at 4–5 years of age with a L₅₀ of 68 cm, whereas males matured at 2–3 years of age with a L₅₀ of 51 cm. The commercial fishery in New South Wales was characterised by declining catches and a reduction in the proportion of mulloway of mature lengths in landings. During 2002–2005 commercial landings were dominated (83%) by fish within 15 cm of the current minimum legal total length of 45 cm and aged 2 and 3 years (>80%), even though mulloway can attain lengths of 200 cm and live >30 years. Estimates of the rates of instantaneous total mortality ranged between 0.34 and 0.45, whilst the rate of instantaneous natural mortality (M) was estimated to be approximately 0.12. Yield-per-recruit analyses indicated that mulloway in New South Wales are being growth overfished and substantial increases in yield could be achieved by increasing the length at first harvest. Values of the spawning potential ratio were below 0.2 under a range of mortality estimates, suggesting that mulloway are at risk of recruitment overfishing. These results suggest that the spawning stock of mulloway in south-eastern Australia has been depleted and that remedial management action is required to protect this iconic species.     

驼背鲈(Chromileptes altivelis)的胚胎发育及仔、稚、幼鱼形态观察

对驼背鲈(Chromileptes altivelis)的胚胎发育及仔、稚、幼鱼的形态特征进行了详细的观察与研究,描述了从受精卵到仔、稚、幼鱼各发育期的时间和形态特征变化。结果表明,在水温25-26℃、盐度30的海水中,受精卵历时27 h 25 min完成整个胚胎发育过程,经历从卵裂、囊胚、原肠、神经胚到肌节形成、各器官的逐渐形成、变化、完善等一系列的胚胎发育和变化过程;根据其卵黄囊消长情况、鳞片的覆盖状态、体色发生的不同变化以及第二背鳍和腹鳍的消长,将胚后发育分为仔、稚、幼鱼3个阶段。在水温22-26℃、盐度29-31、DO≥5 mg/L的条件下,2-3 d仔鱼卵黄囊消失,开口摄食;生长发育至31 d,仔鱼已变态进入稚鱼期;培育至57 d,稚鱼完成变态,成为幼鱼。第二背鳍棘和腹鳍棘的生长与收缩等石斑鱼类早期发育的共性生长特征及其体表特性体色变化特征为驼背鲈胚后发育过程中最明显的特征。     

Marine and coastal protected and conserved areas strategy in Brazil: Context,lessons, challenges,finance, participation,new management models,and first results

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Effects of Mosquitofish,Gambusia affinis,on Channel Catfish,Ictalurus puncatatus,Production Ponds

Mosquitofish, Gambusia sp., have been spread throughout the world to biologically control mosquitoes. However, the fish has gained a reputation as an invasive species and has been implicated in displacing native aquatic species. Gambusia affinis are native to the southeastern United States and commonly occur in commercial channel catfish, Ictalurus punctatus, production ponds. We investigated effects of mosquitofish presence on zooplankton populations, water quality, disease occurrence, and fish production in experimental ponds. There were no differences between ponds with or without mosquitofish in numbers of calanoid copepods, cyclopoid copepods, total copepods, Bosmina sp., Ceriodaphnia sp., Moina sp., Daphnia sp., or total cladocerans. There were also no differences in copepod and cladoceran sizes. Copepod nauplii were more numerous during the summer months in ponds with mosquitofish. There were no differences in water quality variables (soluble reactive phosphorus, nitrate, nitrite, ammonia, total nitrogen, total phosphorus, pH) or phytoplankton density between ponds stocked with and without mosquitofish. Catfish production and disease occurrence were also similar between ponds with and without mosquitofish. Although mosquitofish may cause problems when stocked outside their native range, there does not appear to be any adverse effects of mosquitofish presence in catfish production ponds.     

Factors influencing the abundance of the common bully, Gobiomorphus cotidianus McDowall, in small, North Island, New Zealand, lakes

Adult common bullies, Gobiomorphus cotidianus McDowall, are small (total length =  30–120 mm), benthic fish commonly found in the littoral zones of New Zealand lakes where they are a major prey species for trout and eels. Differences in their relative abundance (CPUE) were determined between 21 shallow North Island lakes. Mean CPUE ranged from 2 to >  1000 fish net^{− 1} night^{− 1} and was inversely related to water transparency. The abundance of bullies was not reduced in lakes containing rainbow trout, Oncorhynchus mykiss (Walbaum), but was reduced in all lakes containing self-recruiting populations of eels, Anguilla spp. Mean densities of planktonic larval bullies in the limnetic zone were also inversely related to water transparency. Since low water transparency is related to increased trophic status for these lakes, the abundance of bullies is likely to be related to lake productivity, rather than turbidity.     

Annual Meeting of the Pacific Fisheries Technologists,Red Lion Inn,San Diego,CA, February 18-21, 1996

No abstract available for this article.