北方池塘驯化养鲤高效技术措施

2015年,黑龙江省肇源县肇源镇兴安村陈功林,采取池塘驯养鲤鱼,取得较高的经济效益.他池塘驯化主养鲤鱼面积280亩,其中鱼种50亩、成鱼230亩,以80∶20放养模式为主.鱼种池共放养鲤鱼夏花鱼种20万尾,鲢、鳙、草鱼夏花鱼种6万尾;共投喂鲤鱼苗种饲料43吨;共产鲤鱼秋片鱼种3.1万kg,鲢、鳙、草鱼秋片鱼种0.75万kg.成鱼池放养鲤鱼春片鱼种2.9万kg、规格2.5 ～ 3.5kg/尾,鳙鱼春片鱼种2850尾、规格1～ 1.5kg/尾,鲢鱼种9000尾;共投饲料60吨;共产鲤成鱼17.5万kg、平均规格为5.5kg/尾,其中鳙鱼1.54万kg、鲢鱼2.9万kg.总投资230万元,总收入275万元,总盈利45万元,平均亩盈利1607元.以下介绍其主要技术措施.     

翘嘴红鲌苗种繁育及成鱼养殖试验

2004～2005年进行了翘嘴红鲌人工繁殖、夏花与冬片鱼种培育、成鱼池塘与网箱养殖试验,取得较好效果。2004年：催产亲鱼25组,出苗340万尾；3口发花池经25天饲养共产夏花鱼种24.91万尾,平均体长3.0～3.3 cm；3口育种池经140天培育共产冬片鱼种6.38万尾,平均体长12.4～14.3 cm,利润2660～2937元/667m~2,投产比1：2.64～2.82。2005年：3口成鱼池共产商品鱼7445 kg,平均单产413.6 kg/667m~2,利润4546～6333元/667m~2,投产比1：2.15～2.53；4口网箱共产商品鱼2558kg,平均单产32.0 kg/m~2,利润352～413元/m~2,投产比1：2.01～1：2.03。     

沿黄地区一年两茬鲤鱼养殖技术

总结了"一年两茬"池塘鲤鱼养殖技术要点。在郑州市沿黄地区池塘进行一年两茬养殖试验,第一茬养殖商品鱼,4月中旬至5月初放养规格200~300g/尾的大规格春片鱼种,7月初商品鱼出池上市;第二茬培育鱼种,成鱼出池后放养夏花鱼种,进入第二茬鱼养殖。通过采取梯次投放鱼种、科学投饲,适时调控水质和综合防治鱼病等,实现池塘顺次养殖,商品鱼错峰上市,对养殖户具有一定的借鉴意义。     

池塘主养白须公试验

在0.27 hm2土池进行了主养红白须公秋片鱼种试验,放养红白须公夏花33855尾,白鲢夏花6000尾,花鲢夏花2000尾。经97 d饲养,出塘红白须公秋片17360尾,1675.24 kg,平均体重96.5 g,成活率51.2%,花、白鲢秋片580 kg,平均产鱼8457.15 kg/hm2,其中红白须公占77.3%,产值达108 750元/hm2。     

渔牧结合 科学致富

我是林甸县勤俭村的一个普通农民。我靠养鱼和养猪走上富裕路。 1998年我利用自己修建的50亩养鱼池进行养鱼。其中鱼种池面积10亩,共放夏花鱼苗4万尾,其中鲢、鳙鱼占80％,鲤鱼占20％,共产秋片鱼种3 000kg,平均亩产300kg,比1997年提高80kg,秋片鱼种当地价平均每kg8元,产值为2.4万元;成鱼池40亩,平均亩放60kg,其中鲤鱼放养量22kg,鲢、镛鱼放养量38kg,产商品鱼2万kg,平均亩产500kg,商品鱼每kg售价为10元,产值为20万元。渔     

大规格鲤、鲢鱼种高产技术试验

1988年,任丘市鱼种场采用综合科学养鱼技术,在面积为13亩、水深1.2～2.2米的旧坑塘中,培育以鲤鱼为主和少量鲢鱼的大规格鱼种,取得成功。当年6月7日投放鲤鱼夏花18.9万尾,尾重0.415克;6月30日投放鲢鱼夏花6.5万尾,尾重0.208克。至10月上旬,总产达1.64万公斤,亩均1262公斤;其中鲤鱼鱼种13612公斤,亩均1047公斤,鲢鱼鱼种2788公斤,亩均215公斤。鲤鱼鱼     

唐明奎稻田养鱼夺高产

大田乡桥头村村民唐明奎利用1亩责任田在种好水稻的同时，开展稻田养鱼。取得了可喜的成绩。1989年5月8日投放夏花鱼种420尾。其中草鱼夏花100尾，鲤鱼夏花320尾，10月23日起水20-24厘米的大规格草鱼种47尾，鲤鱼284尾，重71公斤，鱼产值311元，获纯利281元，两季共收获稻谷920公斤。     

推广驯化养鱼 创高产 增效益

我县上集镇诺敏河村农民李永生1987年开始从事养鱼生产,一直采取传统方式,1998年承包了村里的鱼种场,养鱼水面达200亩,其中:鱼种池100亩,越冬池30亩,商品鱼池70亩,通过采用驯化养鱼技术,调整品种结构,取得了较好的经济效益。 1998年,该场共投放春片鱼种2900kg,其中:鲤鱼1670kg,鲢、镛鱼500kg,草鱼80kg,杂交鲫450kg,野生鲶鱼200kg。投放乌子鱼苗91万尾,其中:鲤鱼59万尾,鲫鱼11万尾,草鱼6万尾,鲢、镛鱼12万尾,鳊花1万尾,野生鲶鱼2万尾。共生产商品鱼25000kg,秋片鱼种26000kg,全场平     

太湖放流鱼蟹鳖17万公斤

江苏省太湖渔业管理委员会,为了充分利用太湖天然饵料资源,增加名贵及特种水产品产量,1990年投资120万元,先后人工放流了青鱼、草鱼、鳊鱼、鲤鱼、鲢鱼一龄春片鱼种556万尾,鲤鱼和鲫鱼夏花鱼种8299万尾,幼蟹2554公斤,蟹苗1389公斤,幼鳖1.4万只,幼鳗17.78万尾,总     

全雌鲤的育种和养殖技术

全雌鲤是中国科学院水生生物研究所科技人员,结合生产实践培育出的一种由当年鱼苗养成商品鱼的养殖新对象。1989～1991年,通过钟祥县水科所等单位的养殖实践证明,全雌鲤具有比其他鲤鱼生长速度快,养殖周期短,成本低,体型好,丰满度高等优点。在一亩鱼种池或成鱼塘套养50尾夏花全雌鲤鱼种,当年尾重均可达到0.5公斤以上,商品率100%。比对照池每亩放普通鲤鱼夏花50尾,年底只能长到0.2公斤左右的速度快二倍以上。从鱼苗养到0.5公斤的商品鱼,养殖周期也比普通鲤鱼缩短     

Association between the interannual variation in the oceanic environment and catch rates of bigeye tuna (Thunnus obesus) in the Atlantic Ocean

The environmental processes associated with variability in the catch rates of bigeye tuna in the Atlantic Ocean are largely unexplored. This study used generalized additive models (GAMs) fitted to Taiwanese longline fishery data from 1990 to 2009 and investigated the association between environmental variables and catch rates to identify the processes influencing bigeye tuna distribution in the Atlantic Ocean. The present findings reveal that the year (temporal factor), latitude and longitude (spatial factors), and major regular longline target species of albacore catches are significant for the standardization of bigeye tuna catch rates in the Atlantic Ocean. The standardized catch rates and distribution of bigeye tuna were found to be related to environmental and climatic variation. The model selection processes showed that the selected GAMs explained 70% of the cumulative deviance in the entire Atlantic Ocean. Regarding environmental factors, the depth of the 20 degree isotherm (D20) substantially contributed to the explained deviance; other important factors were sea surface temperature (SST) and sea surface height deviation (SSHD). The potential fishing grounds were observed with SSTs of 22–28°C, a D20 shallower than 150 m and negative SSHDs in the Atlantic Ocean. The higher predicted catch rates were increased in the positive northern tropical Atlantic and negative North Atlantic Oscillation events with a higher SST and shallow D20, suggesting that climatic oscillations affect the population abundance and distribution of bigeye tuna.     

Growth performance,digestive enzyme activity and immune response of Japanese sea bass,Lateolabrax japonicus fed with fructooligosaccharide

In this experiment, a feeding trial was performed to determine the effects of fructooligosaccharide (FOS) on growth performance, digestive enzyme activity and immune response of Japanese sea bass, Lateolabrax japonicus juveniles (initial weight 38.3 ± 0.5 g), and the fish were examined following feeding with six levels of FOS (0, 0.5, 1, 2, 4 and 6 g/kg) for 28 days. Significant enhancement of weight gain (WG) and specific growth rate (SGR) was found in fish fed 1 g/kg FOS incorporated diets (p < .05), while the feed conversion ratio (FCR) in the 1, 2 g/kg FOS groups reduced significantly compared with the control (p < .05). Besides, the crude lipid in the 4, 6 g/kg FOS groups increased significantly compared with the control (p < .05). On the other hand, the erepsin and lipase activities significantly elevated in intestine of fish fed 2 g/kg FOS (p < .05) and the lysozyme activity in serum of fish fed 2 g/kg FOS were significantly higher than that in the control (p < .05). Moreover, the alkaline phosphatase activities in serum of fish fed 0.5, 1, 2 g/kg FOS were significantly higher than in control (p < .05). Regression analysis showed that the relationships between dietary FOS levels and either SGR, FCR, erepsin or lysozyme activities were best expressed by regression equations, and the optimal inclusion levels are 1.37, 1.80, 3.06, 3.11, 1.93 and 1.80 g/kg for SGR, FCR, erepsin, lipase, lysozyme and total superoxide dismutase activities, respectively. Overall, this study revealed that FOS incorporated diets could beneficial for L. japonicus culture in terms of increasing the growth, digestion and immune activities. Under the present experimental condition, the optimal supplementary level of FOS in the diet of L. japonicus is 1–3 g/kg.     

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).     

Involvement of gonadal steroids in final oocyte maturation of white perch (Morone americana) and white bass (M. chrysops): in vivo and in vitro studies

Plasma estradiol-17 (E₂), testosterone (T), 17,20-dihydroxy-4-pregnen-3-one (DHP) and 17,20,21-tri-hydroxy-4-pregnen-3-one (20-S) levels were measured by radioimmunoassay (RIA) in white perch (Morone americana) and white bass (M. chrysops) that were induced to undergo final oocyte maturation (FOM) with human chorionic gonadotropin (hCG). Plasma DHP levels increased in females of both species in association with oocyte germinal vesicle migration (GVM) and germinal vesicle breakdown (GVBD) and decreased thereafter. Plasma 20-S levels also increased with oocyte GVM in white bass, but were several-fold lower than DHP levels. Circulating E₂ and T levels were greatest during GVM and GVBD in both species and decreased to low levels during oocyte hydration and ovulation. Follicles from white perch and white bass which received a priming injection of hCG in vivo, produced both DHP and 20-S in vitro after exposure to hCG and their oocytes underwent GVBD. Ovarian incubates from unprimed fish of either species produced only E₂ and T and their oocytes did not complete GVBD. Oocytes from unprimed bass, but not perch, matured when follicles were exposed to hCG in vitro. Both trilostane and cycloheximide blocked in vitro production of DHP and 20-S and oocyte GVBD by white perch follices. DHP and 20-S were equipotent inducers of FOM in the GVBD bioassay. None of several other structurally-related steroids tested were effective within a physiological range of concentrations. These results indicate a role for DHP and 20-S in the control of FOM in white perch and white bass.     

Cardiac,ventilatory and metabolic responses of two ecologically dissimilar species of fish to waterborne cyanide

Changes in heart rate, ventilatory activity and oxygen consumption were determined in trout (Salmo gairdneri) and brown bullhead catfish (Ictalurus nebulosus) during exposure to a steadily increasing concentration of waterborne cyanide selected to produce death in 8–9 hours for each species. The lethal cyanide concentration for the bullheads was an order of magnitude higher than for trout. Trout developed an immediate and gradually increasing bradycardia throughout the exposure period. Cyanide produced tachycardia in the bullhead followed by a gradual onset of bradycardia as the concentration of cyanide was raised. Pericardial injection of atropine (a muscarinic cholinergic antagonist) indicated that bradycardia in the trout was due initially to increased vagal tone but later due to the direct effect of cyanide on the heart. Hyperventilation in the trout persisted throughout the exposure period, although the rate and amplitude fluctuated and was variable between individual fish. During the last hour of exposure (highest cyanide concentration), ventilation was characterized by rapid, shallow breaths followed by a sudden respiratory arrest. The bullheads exhibited hyperventilation during the first 3 hours of exposure followed by a gradual, linear drop in ventilation rate and amplitude until death occurred. Cardiac and ventilatory responses in both species were attributed to stimulation of central and peripheral chemoreceptors by cyanide. Evidence is presented which suggests the initial response in the bullheads was due, at least in part, to gustatory stimulation by the cyanide. Oxygen consumption of the trout remained above pre-exposure levels for the majority of the test period. Oxygen consumption in the bullhead paralleled the changes in heart and ventilatory rates. Whole-body lactate levels of fingerlings of both species during cyanide exposure were measured to estimate the extent of anaerobiosis. Whole-body lactate levels were much greater in the bullheads than the trout, indicating a higher capacity for anaerobiosis, possibly due to a greater fuel supply. Overall, the trout responded to cyanide in a manner similar to that produced by environmental hypoxia whereas the bullheads experienced a gustatory stimulus which masked the hypoxia-like response.     

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.