花斑裸鲤在３种环境中的驯化养殖试验

首次报道了黄河上游特有鱼类花斑裸鲤(Gymnocypris eckloni)在池塘、流水池、网箱中人工驯化养殖试验情况。395g/尾的花斑裸鲤855尾,经过170d的池塘驯养,成活778尾,驯养成活率91.0%,均重450g/尾,平均增重55g/尾,增重率13.9%;378g/尾的花斑裸鲤405尾,经过180d的流水池驯养,均重530g/尾,平均增重152g/尾,增重率40.2%,成活308尾,驯养成活率76.0%;345g/尾的花斑裸鲤2029尾,经过14个月的网箱驯养,均重500g/尾,平均增重155g/尾,增重率44.9%,成活1002尾,驯养成活率49.4%。野生花斑裸鲤驯养试验平均总成活率为72.1%。寄生虫病是导致花斑裸鲤成活率偏低的主要原因。驯养试验对黄河上游土著鱼类的人工繁育和增殖保护具有一定的借鉴意义。     

花斑裸鲤在3种环境中的驯化养殖试验

首次报道了黄河上游特有鱼类花斑裸鲤(Gymnocypris eckloni)在池塘、流水池、网箱中人工驯化养殖试验情况。395g/尾的花斑裸鲤855尾,经过170d的池塘驯养,成活778尾,驯养成活率91.0%,均重450g/尾,平均增重55g/尾,增重率13.9%;378g/尾的花斑裸鲤405尾,经过180d的流水池驯养,均重530g/尾,平均增重152g/尾,增重率40.2%,成活308尾,驯养成活率76.0%;345g/尾的花斑裸鲤2029尾,经过14个月的网箱驯养,均重500g/尾,平均增重155g/尾,增重率44.9%,成活1002尾,驯养成活率49.4%。野生花斑裸鲤驯养试验平均总成活率为72.1%。寄生虫病是导致花斑裸鲤成活率偏低的主要原因。驯养试验对黄河上游土著鱼类的人工繁育和增殖保护具有一定的借鉴意义。     

安徽省水生生物资源增殖放流效果初显

据安徽省农委渔业局统计,2012年安徽省组织实施了一系列的增殖放流活动,总计投入资金2449万元,放流各类水生生物苗种2．82亿尾,其中鲢鱼4599万尾,鳙鱼5117万尾,青鱼228万尾,草鱼991万尾,鲤200万尾,鲫490万尾,胭脂鱼58万尾,大鲵1200尾,超额完成了下达我省的放流2．68亿尾苗种的任务,为保护生物多样性、改善水域生态环境、促进渔业可持续发展发挥了重要作用。主要特点：一是工作力度显著加大。中央财政转移支付资金的支持大大提升了各地开展增殖放流的工作热情,     

一例草鱼烂鳃并发赤皮病的治疗

汀苏射阳县旺阳水产养殖公司陈老板有160亩塘口,水深约为1．8米,共放养规格为6尾／斤左有的草鱼50000尾,套养3尾／斤的花白鲢9600尾。4月28日突降暴雨,5月1日陈老板发现草鱼死广了11尾,5月2日死亡了30尾,5月3日死亡了43尾。     

斑尾复虾虎鱼池塘大棚生态早繁试验

为了实现斑尾复虾虎鱼的生态早繁,于2014年底在菊黄东方鲀越冬池内进行斑尾复虾虎鱼的繁殖试验。越冬主养鱼为1龄菊黄东方鲀鱼种,平均规格为45.0 g/尾,放养密度在3 033尾/亩(15亩=1 hm~2,下同)。2014年11月19日挑选斑尾复虾虎鱼亲鱼90尾,雌雄比为1∶1,雌、雄鱼的平均规格分别为150、200 g/尾,平均每亩放养量为10尾。试验结果:翌年4月28日,共起捕菊黄东方鲀1 860.0 kg,平均规格为69.0 g/尾,越冬成活率为98.7%;获得斑尾复虾虎鱼苗种共计135100尾,平均规格为4.19 cm/尾,平均每尾雌亲鱼产鱼量为3002尾。结果表明,利用菊黄东方鲀越冬池放养斑尾复虾虎鱼亲鱼,挑选规格合适的亲鱼,掌握好亲鱼雌雄配比、放养数量等,后期无需进行注射催产激素等人工干预,即可实现全生态育苗。     

哈尔滨市松嫩土著鱼类研究所 哈尔滨市康安渔业机械商店

正跟踪本专业国内外发展最新动向,为您提供最适合黑龙江渔业生产的名优鱼苗和渔机设备。鱼苗:●春片:鳜鱼10万尾(50克/尾)、兴凯湖白鱼(8—10厘米)20万尾、云斑鮰(8—10厘米)10万尾、镜泊湖红尾(8—10厘米)20万尾、唇(10—13厘米)30万尾●夏花:鳜鱼(2-10厘米)100万尾、翘嘴红鲌(2-3厘米)200万尾、镜泊湖红尾(2-3厘米)20万尾、怀头鲶(3-     

由纤毛虫引起的叉尾鮰鱼病的防治

涪陵区龙桥镇金锅一社一养殖户承包的一口0．72hm^2池塘，2004年3月份投放叉尾鮰730kg，平均规格50g／尾。7月14日出现叉尾鮰死亡，第一天死4尾（平均规格350个／尾），第二天8尾，第三天40多尾，最多一天死亡110尾，连续几天死亡叉尾鲴284尾，99．4kg。经诊断系纤毛虫病引起死亡。同年8月6日-10日，涪陵区卫东水库网箱养殖的叉尾鮰鱼种（10—12cm）因患车轮虫病，第一天死亡10几尾，第二天死亡20多尾，第三天死亡400多尾，最多一天死亡600多尾，     

池塘主养斑点叉尾试验

在一面积为 5.4亩的池塘中 ,主养斑点叉尾 ,亩放养斑点叉尾冬片鱼种 730尾 ,规格 18.8克 /尾 ,经 2 70天养殖 ,取得亩产斑点叉尾成鱼 4 2 0kg ,规格 650克 /尾 ,成活率 88.5% ,亩产值8895元 ,亩效益 4 60 4 .8元的结果     

日本海水养殖发生严重病毒性鱼病

根据日本水产厅透露,由于前年秋季以来以养殖的真鲷稚鱼为主感染了病毒性红细胞坏死病,导致1991年养殖鱼类死亡509万尾,直按经济损失达8亿日元。其中真鲷495万尾、(鱼师)鱼31000尾、竹(竹夹)鱼3万尾、紫(鱼师)28000尾、石鲷27000尾、长缟鲹15000尾、斑石鲷4000尾、黄尾(鱼师)3000尾、长棘鲷2000尾、鲈500尾。真鲷     

细菌性败血症的有效防治

开县温泉镇东坪村6组一养殖户新建一口1．33hm^2池塘，2006年4月投放草鱼种5000尾（200g／尾）、鳊鱼2000尾（250g／尾）、鲫鱼400尾（25g／尾）、花鲢80尾（200g／尾）、白鲢500尾（150g／尾）。6月中旬发病死鱼，开初死鲫鱼、鳊鱼，过后陆续死白鲢和草鱼，连续一周总计死鱼425kg。经诊断是细菌性败血症引起的死亡。     

Rare serotype occurrence and PFGE genotypic diversity of Streptococcus agalactiae isolated from tilapia in China

Previously, we reported 10 PEGE types of 85 tilapia Streptococcus agalactiae(GBS), which shifted from Streptococcus iniae in China, by using PEGE method. Presently, larger and more representative tilapia GBS were isolated, for the ?rst time in China, to characterize their serotypes and genetic diversities more precisely than had done before. 168 GBS strains were distributed in ?ve provinces of China, in which Guangdong, Guangxi and Hainan were the major ones, holding36.9%(62/168), 37.5%(63/168) and 19.6%(33/168), respectively. Serotypes, Ia, Ib and III, were observed in these strains and the most predominant one was Ia(95.2%), which mainly distributed in Guangdong, Guangxi and Hainan. Ia initially occurred in 2009, it shoot up to 32.1% in 2010,but decreased to 16.1% in 2011 before went up to 45.2% in 2012. Ib sporadically occurred during2007–2011, III onlyoccurred in 2012. 14 different PFGE types, including 4 new types(N, O,P and Q), were observed, in which B, D, F and G were the predominant types, holding 83.9%(141/168) of the total GBS strains. Ia corresponded to 11 PFGE types(A–H, N–P), in which type D predominated(51%). Ib represented 3 genotypes(I, J and Q) and III harbored only 2genotypes(N and F). Type N and Fsynchronously presented in Ia and III. In summary, the genetic diversity of tilapia GBS varied by serotypes and changed with geographical locations and years.Although Iastillpredominated, new rareserotypeIII alreadyoccurred in China.     

Growth hormone (GH) and reproduction: a review

Interaction between growth and reproduction occurs in many vertebrates and is particularly obvious at certain stages of the life cycle in fish. Endocrine interactions between the gonadotropic axis and the somatotropic axis are described, the potential role of GH being emphasised. A comparative analysis of these phenomena in mammals, amphibians and fish, suggests a specific role of GH in the physiology of puberty, gametogenesis and fertility. It also shows the original contribution made by studies on the fish model in this field of investigations.     

Purification and partial characterization of GtHs (cfLH and cfFSH) from Indian walking catfish (Clarias batrachus) (L.) and development of a homologous ELISA for cfLH

Two gonadotropins (GtH; Qa and Qb) were purified by gel filtration and ion exchange chromatography from the pituitaries of Indian walking catfish (Clarias batrachus). The presence of GtH during purification was assessed by in vitro oocyte maturation and in vivo steroidogenic activity, and their identities were determined by elution profiles, molecular weight, biological activities and yield. The molecular weights of Qa and Qb were 37 and 42 kDa, respectively, and composed of distinct subunits (Qa: 20 and 14 kDa and Qb: 26 and 18 kDa). Polyclonal antibodies raised against Qa immunostained Qa, Qb and pituitary GtH cells. A competitive Qa‐ELISA was developed whose sensitivity was 6.25 ng mL^?1 (1.25 ng well^?1) with intra‐ (3.5%) and inter‐ (12.4%) assay coefficients of variation. Displacement curves parallel to the standard were obtained with plasma and pituitary extracts of catfish, Qb and carp GtHII. The assay was validated by measuring the plasma Qa levels after LHRH treatment and in relation to ovarian growth in the female catfish during different reproductive phases. Based on the results, Qa and Qb corresponded to fish LH and FSH respectively. The findings will increase the knowledge of the mechanisms controlling fish reproduction and identification of sensitive phases in fish in captivity for hormonal manipulation.     

Controlled infection of Poecilia reticulata Peters (guppy) with Tetrahymena by immersion and intraperitoneal injection

Tetrahymena is a protozoan parasite, which infects guppy, Poecilia reticulata Peters, and causes substantial economical losses in commercial farms worldwide. Studies of guppy infected by Tetrahymena require standardized infection protocols. The LD50 for Tetrahymena infection of guppies by intraperitoneal (IP) injection was calibrated, and the level obtained was 946 parasites per fish. Guppy infection with Tetrahymena by immersion, imitating the natural route of infection via the integument, was studied under normal or stress conditions. Exposure to cold and netting (CNI) and to cold only (CI) followed by immersion exposure to 10 000 Tetrahymena per mL resulted in 22.5% and 19.2% mortality, respectively, as compared to 14.2% and 10% in groups that were netted only (NI) or non‐stressed (I). Histopathology revealed that immersion infection resulted in a systemic infection. Lysozyme levels, measured 3 weeks after infection, were significantly higher in the CNI group (288 μg per mg protein) compared with CI‐, NI‐ and I‐treated groups (94.5, 64 and 62.3 μg mg^?1, respectively). There was no evident parasite immobilization activity in body homogenates, suggesting no development of acquired immunity. Re‐infection by IP injection revealed no increase in protection in any of the treatment groups, mortality range of 56.3–75%, higher than in the non‐exposed control (40.6% mortality).     

Evaluation of a Fast Method Based on the Presence of Two Restriction Sites in the Mitochondrial ND5 (mt ND5) Gene for the Identification of Scomber Species

The purpose of this work was to evaluate the suitability of a method based on the presence of two restriction sites (for Hae III and Hindf I) in the mitochondrial NADH dehydrogenase subunit 5 (mt ND5) gene to identify Scomber species. The evaluation was performed on 144 reference and market samples by sequencing of the entire 505-bp fragment of the mt ND5 gene and of a 464-bp fragment of the Kocher fragment of the cytochrome b gene (mt Cytb). Sequence analysis of any of the two fragments allows the identification of each of the four Scomber species, but S. japonicus and S. colias had the same restriction sites at the ND5 amplicon and would not have been differentiated by this analysis. Similarly, loss of the Hae III site in some S. scombrus individuals would have misidentified them as not being Scomber. All the market products were correctly labeled except one acquired in Spain labeled as originating in the Atlantic and containing S. japonicus.     

Nitrogenous waste excretion and accumulation of urea and ammonia inChalcalburnus tarichi (Cyprinidae), endemic to the extremely alkaline Lake Van (Eastern Turkey)

The endemic, anadromous cyprinidChalcalburnus tarichi is the only fish species known to occur in alkaline Lake Van (Eastern Anatolia, Turkey). EightC. tarichi were maintained individually in Lake Van water (17 – 19°C; pH 9.8; 153 mEq·I^–1 total alkalinity; 22 total salinity) and tank water samples analyzed for 24 h in 2 to 4 h intervals. At zero time, < 1µM ammonia was present and urea was undetectable in the tank water; at 24 h, total ammonia and urea made up 114±32 and 35±25µM, respectively. Over the experimental period, ammonia-N and urea-N excretion averaged 1041±494 and 607±169moles·kg^–1 fish·h^–1, respectively. The extent of urea excretion was highly variable between specimens. Uric acid excretion was not detectable.Urea was present at high concentrations in all tissues and plasma (25 – 35moles·g^–1·ml^–1) of freshly caughtC. tarichi; total ammonia content of the tissues was by a factor of 1.9 (liver) to 3.0 (brain) lower. High arginase activity (2.4±0.2 U·min^–1·g^–1) was detected in the liver ofC. tarichi but ornithine carbamoylphosphate transferase, a key enzyme of the ornithine-urea-cycle, was absent. Ureagenesis is likely through degradation of arginine and/or uricolysis. High glutamine synthetase activity (11±0.6 U·min^–1·g^–1) and low ammonia content in brain suggest that, like other teleosts,C. tarichi has an efficient ammonia detoxification in the brain, but in no other tissue.Nitrogenous waste excretion at alkaline pH is discussed. The ability ofC. tarichi to excrete high levels of ammonia at extremely alkaline pH is unique among teleosts studied so far. The mechanism of ammonia excretion under Lake Van conditions remains to be elucidated.     

Imported ornamental fish are colonized with antibiotic‐resistant bacteria

There has been growing concern about the overuse of antibiotics in the ornamental fish industry and its possible effect on the increasing drug resistance in both commensal and pathogenic organisms in these fish. The aim of this study was to carry out an assessment of the diversity of bacteria, including pathogens, in ornamental fish species imported into North America and to assess their antibiotic resistance. Kidney samples were collected from 32 freshwater ornamental fish of various species, which arrived to an importing facility in Portland, Oregon from Colombia, Singapore and Florida. Sixty‐four unique bacterial colonies were isolated and identified by PCR using bacterial 16S primers and DNA sequencing. Multiple isolates were identified as bacteria with potential to cause disease in both fish and humans. The antibiotic resistance profile of each isolate was performed for nine different antibiotics. Among them, cefotaxime (16% resistance among isolates) was the antibiotic associated with more activity, while the least active was tetracycline (77% resistant). Knowing information about the diversity of bacteria in imported ornamental fish, as well as the resistance profiles for the bacteria will be useful in more effectively treating clinical infected fish, and also potential zoonoses in the future.     

Effect of iodophor disinfection of non‐hardened Salmo trutta eggs on their bacterial and fungus load

This study investigated the efficiency of iodophor disinfection (135 ppm active iodine for 15–30 min) of non‐hardened Salmo trutta eggs against different groups of bacteria and against fungus. Egg samples were taken from non‐disinfected and from disinfected eggs, microorganisms were cultured on specific nutrient media and their mass was measured by turbidimetric methods. Bacteria and fungus mass of non‐hardened eggs could be reduced but not eliminated by iodophor disinfection with 135 ppm active iodine for 15 min. The extent of reduction was 47–65% (Experiment 1). The efficiency of disinfection increased with disinfection time as the reduction in bacteria and fungus mass was 40–55% after 15 min and 58–74% after 30 min (Experiment 2). Disinfection efficiency of iodophor solution diluted in water (reduction 49–57%) and of iodophor solution diluted in sodium chloride solution iso‐osmolar to the oocytes (reduction 52–61%) was similar (Experiment 3). The reduction in bacteria and fungus mass was persistent as it was 39–72% lower in embryos deriving from disinfected eggs than in embryos deriving from non‐disinfected ones (Experiment 4). In conclusion, the tested disinfection method is inadequate to eliminate pathogens completely but it could positively influence immune defence of eggs and embryos.