加州鲈池塘养殖试验

加州鲈又名大口黑鲈，原产北美洲，是美、加两国内陆放流增殖和池塘养殖的主要鱼类，１９８３年引入广东，１９８５年国内人工繁殖成功。后推广全国各地，现池塘、湖泊、水库等各种水体养殖均见报道。我们于１９９８、１９９９两年进行了该鱼的池塘养殖，已初见成效，现报道如下： 一、材料方法 鱼苗于１９９８年７月５日购于沈阳市苏家屯区新华畜牧场，尾数７０００，规格３－５ｃｍ，养殖池塘面积３．５亩，水深１．５ｍ，地下水源，池塘周围有芦苇，约占总养殖面积的１０％。 二、池塘养殖及日常管理 １、清塘．放养前５天用生石灰清塘，…     

攀鲈池塘高产养殖试验

攀鲈（地方名甘毛），攀鲈属，鲈科。主要分布于我国南方，多栖息于江河、池塘、水沟等淡水水域。具有适应性强，耐低氧，食性杂，肉嫩味美等特点，深受消费者喜爱。适宜pH６～９，生长水温１８～３５℃，最适生长水温２５～３０℃，低于１５℃停止摄食，属热带、亚热带淡水野生经济鱼类。笔者在人工催产取得突破的基础上，进行池塘高产养殖试验，现将情况报告如下。一、池塘条件与方法１．池塘条件试验池塘为沙质土壤，不渗漏，淤泥深２０厘米左右，水深１．３～１．５米，水源为南渡江渠道灌溉用水，四周通风透阳。２．池塘的消毒与施肥…     

加州鲈鱼养殖技术（三）

５成鱼养殖加州鲈成鱼养殖主要有池塘单养、混养和网箱养殖几种方式。５．１池塘单养５．１．１池塘条件养殖池塘要求水源充足 ,水质良好 ,不受污染 ,排灌方便 ,池塘底质淤泥少 ,以壤土为宜 ,上铺一层细沙更好。池子面积以１０００～２０００ 为宜 ,水深１．５ｍ～２ｍ ,要设置排灌水口和防逃设施 ,高密度养殖时 ,还需配有增氧设备 ;池塘使用前可按常规方法清塘消毒 ,杀灭敌害生物和病原菌。５．１．２鱼种放养所投的鱼种体质要健壮 ,无病无伤 ,大小规格要一致 ,一次放足。实践证明 ,投放１０ｃｍ以上规格鱼种 ,不但成活率高 ,而且养殖效益…     

北方地区池塘主养加州鲈试验

北方地区池塘主养加州鲈试验我国自８０年代初首次从台湾引进加州鲈，随后广东、浙江、江苏等地相继引种。在北方地区有过池塘套养的试验，而池塘主养却无报道，我们于１９９３年从广州引进加州鲈夏花鱼种在洮南市水产良种场进行池塘主养试验，取得了较好的养殖效果，现将...     

花鲈在纯淡水池塘的大面积集约化高产养殖报告

花鲈(Lateolobrax japonicus)的集约化养殖在咸淡水池塘已取得成功，并进入了商品化生产时期。花鲈在纯淡水封闭式水域进行养殖，近年来也有些试验，但作为大面积的池塘高产养殖尚没见报导。本试验旨在探索纯淡水池塘集约化养殖花鲈的可行性及其大面积高产养殖的途径。     

鲈生物学及池塘养殖技术

报道了鲈繁殖、食性、摄食、生长等习笥及鲈池塘养殖技术，在山东越冬的３种方式、鲈的主要病害及防治。     

不同养殖模式下加州鲈营养成分差异分析

为了解池塘养殖和工厂化循环水养殖加州鲈营养品质差异,采用国家标准方法测定了两种不同养殖模式加州鲈(Micropterus salmoides)肌肉的常规营养成分、脂肪酸组分和氨基酸组分,并对两者的营养价值进行了分析评价。结果显示:循环水养殖加州鲈肌肉中灰分、粗脂肪和粗蛋白质含量均高于池塘养殖加州鲈,其中粗蛋白含量达到极显著水平;共检测出10种脂肪酸,循环水养殖加州鲈的总脂肪酸、总多不饱和脂肪酸和EPA+DHA均高于池塘养殖加州鲈,总不饱和脂肪酸和总多不饱和脂肪酸的差异达到极显著水平;共检测出17种氨基酸,循环水养殖加州鲈肌肉中各种必需氨基酸(EAA)含量均高于池塘养殖加州鲈,除苯丙氨酸外差异均达到显著或极显著水平,其中赖氨酸含量最高,亮氨酸次之,蛋氨酸含量最低;循环水养殖加州鲈肌肉的总氨基酸、总必需氨基酸、总非必需氨基酸和总鲜味氨基酸含量均高于池塘养殖加州鲈,前三者差异达到极显著水平;根据ASS和CS评分结果,池塘养殖和循环水养殖加州鲈肌肉中第一、二限制性氨基酸为缬氨酸和蛋+半胱氨酸,循环水养殖加州鲈肌肉中EAA的ASS和CS均大于池塘养殖加州鲈,且数值均大于或接近1。结果表明:工厂化循环水养殖加州鲈肌肉较之池塘养殖加州鲈的营养品质更好,更加符合人类膳食的需要。     

加州鲈人工养殖技术的初步研究

对加州鲈在池塘养殖条件下的生长、性腺发育、胚胎发育、稚幼鱼发育及其人工繁殖技术、苗种培育、成鱼养殖技术的研究、观察作了初步描述.研究表明:加州鲈1龄性成熟,当年苗在池塘中养殖150～180天,平均体重在250克左右.池塘单养一般每公顷产2250公斤,混养37.5公斤.     

北方地区鲈鱼大面积越冬试验

鲈鱼 (Lateolabrax Japonicus)又名鲈板、花鲈、寨花、鲈子等等，属近岸浅海鱼类，喜栖息于河口咸淡水处，是人工养殖的优良品种之一。东营市地处黄河入海口，自然鲈鱼苗种资源十分丰富。由于池塘养殖当年达不到商品规格，制约了鲈鱼池塘养殖在黄河三角洲地区的发展，致使大量本地鲈鱼苗远销南方诸省及日本、韩国。针对制约鲈鱼养殖发展的关键环节——鲈鱼大面积池塘越冬技术难关， 1997～ 1998年，我们依据池水盐度不同结冰点不同，致使同一区域不同盐度鱼池底层水温不同的原理，对鲈鱼在自然环境下的大面积越冬技术进行全面研究和成功…     

海鱼淡养新品种——杂交条纹鲈

杂交条纹鲈是由雄性白鲈与雌性条纹鲈杂交的子一代，具有显著的杂种生长优势：生长快、个体大、产量高、抗病力强、肉质非常鲜美。该鱼是广盐性鱼类，既适于在淡水池塘里饲养．也适于在沿海地区的半咸水池塘里养殖。杂交条纹鲈的外形特征介于它的双亲之间，体略侧偏．被覆鳞片．体     

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.     

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.     

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.     

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.     

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).     

The optimal dietary protein level of juvenile silver sillago Sillago sihama at three dietary lipid levels

A 5 × 3 factorial growth trial was conducted to evaluate optimal dietary protein and lipid levels (dietary protein level, DP; dietary lipid level, DL) for juvenile Sillago sihama (S. sihama) (2.0 ± 0.02 g, initial weight). Fish were fed 15 diets containing 5 DPs (350, 400, 450, 500 and 550 g/kg) and 3 DLs (60, 90 and 120 g/kg) for 8 weeks. The interaction between proteins and lipids significantly influenced the feed conversion ratio, condition factor, body composition, antioxidant indices and lipase activity (p < .05). DP 450 g/kg showed the highest average final body weight. DPs 500 and 550 g/kg significantly decreased the protein efficiency ratio (p < .05). DL 120 g/kg showed the highest percentage weight gain. The low feed conversion ratio was found in diets P45L12, P55L9 and P55L12. Diet P45L12 showed high superoxide dismutase activities. DP 450 g/kg showed the lowest average malondialdehyde content. Lipase activity was increased by increasing DP (p < .05) with a fall at DP 550 g/kg. Under the present experimental conditions, the optimal DP for S. sihama was 450 g/kg under the DL 120 g/kg.     

Vitamin D3 and the renal handling of phosphate in American eels

Cholecalciferol (Vitamin D₃) increased plasma inorganic phosphate concentration in American eels,Anguilla rostrata, in a dose-dependent fashion. This response was more marked in phosphate loaded fish. In control as well as phosphate loaded eels the hyperphosphatemic response to D₃ was associated with a sharp reduction in renal phosphate clearance relative to¹⁴C-polyethelene glycol (PEG) clearance. Glomerular filtration and urine flow rates were not affected by D₃. As renal phosphate clearance, even in phosphate loaded eels, never significantly exceeded that of PEG, it is suggested that D₃ reduced the relative clearance rate of phosphate by increasing renal phosphate reabsorption rather than by reducing the tubular secretion of phosphate.