高体Shi人工育苗技术研究

福建海区人工养殖的高体Ｓｈｉ于５￣７月繁殖,盛期为５月中旬￣６月中旬。成熟亲鱼注射ＨＣＧ就可产卵,产卵率２０％￣９０％,受精率７０％￣８９．８％,孵化率６１．９％￣８２％,水温２２￣２８℃,盐度３２￣３５有利仔,稚、幼鱼的生长发育。苗种培育期间加强了水质管理,饵料生物的营养强化和病害防治等工作,培育出平均叉长为３３．５ｍｍ的幼鱼２２．４万尾,确立一套较完善的育苗生产工艺。     

辽西海域日本对虾生产性移植放流试验

１９９８年５月 ２４～２９日,在辽宁省葫芦岛市连山湾近岸水域放流体长１０．６±１．１ｍｍ的日本对虾２ ７９８．８万尾。 ８月中旬～１０月中旬期间,沿岸作业的 ５３４只渔船兼捕到本种商品虾 ２４．５ ｔ,平均体长 １４７．３ｍｍ,平均体重 ４０．７ ｇ,相当于 ６０．３万尾,回捕率为 ２． １５％,放流投资与增殖虾产值的比例为 １：５．４,效果良好。     

太平湖水库翘嘴红Bo的产卵场及种群控制

太平湖水库翘嘴红Ｂｏ产卵场位于入库河流中，产卵期的流速０．１－０．５ｍ／ｓ，水温２１－３０℃，时间约为６月中旬－７月中旬。雨后流速增加是刺激产卵的主要因素。因过度捕捞，翘嘴红Ｂｏ资源量近年呈下降趋势，有必要在繁殖期对其产卵群体进行适当保护。文章将库内家鱼种的放养规格定为１３．３ｃｍ以上，将翘嘴红Ｂｏ的起捕规格定为５０ｃｍ以上。     

匙吻鲟受精卵的孵化及仔幼鱼养殖技术

１９９４－１９９５年美国引进匙吻鲟受精卵５批２２．７万粒，孵出鱼苗１２万尾，平均孵化率５３．０％，经暂养成活５．４７万尾，平均成活率４５．５％，共培育出５－６ｃｍ幼鱼３．４３万尾，平均成活率６２．８％。以第五批幼鱼培育最理想，培育出２０ｃｍ幼鱼１．６４万尾，成活率８０％。综合报道了匙吻鲟受精卵的孵化及仔幼鱼养殖的关键技术．     

池塘养殖罗氏沼虾技术与方法

池塘面积２．６亩,池深１．７ｍ,条石浆砌池壁,池底淤泥１０～２５ｃｍ,配１．１ｋｗ增氧机一台。５月初清池后施基肥,５月中旬至６月中旬放养淡化虾苗６．８万尾,鲢鱼水花２．５万尾;饲料种类有黄豆、螺蚌、颗粒饲料及过期食品等。９月底至１０月上旬出池,产出成虾２６７ｋｇ,鲢鱼２００ｋｇ;亩平产虾１０２．７４ｋｇ,亩平获利４３８９元。     

美国青蛙繁殖期间的饲养管理

美国青蛙繁殖期间的饲养管理美国青蛙的产卵繁殖一般是一年一次，产卵盛期是每年的３月中旬至７月上旬。如管理得法，一对种蛙一次可繁殖蝌蚪４０００～６０００尾。一、产卵前的饲养管理１．种蛙的选择及配对美国青蛙６～１０个月龄即性成熟，此时即可用作配种。２年龄的...     

太湖花夏花鱼种培育

一、试验材料１．鱼苗来源：夏花鱼种培育试验所用鱼苗，系由将天然亲鱼及人繁后代池塘培育成可催产的成熟亲鱼，经人工催产、受精、孵化而获得。２．培育池塘：夏花鱼种培育试验池塘为普通的养鱼池塘。面积０．４～３．５亩，水深０．８～１．２米，分新开挖塘和老鱼塘。试验塘在放养太湖花鱼苗前均按常规方法用生石灰消毒清塘。３．鱼苗放养：夏花鱼种培育试验的鱼苗放养均在每年的４月中旬５月上旬进行。每批试验即在受精卵孵化出膜后第４～５天放养，放养密度在２．８万～２２．２万尾／亩。二、培育方法１．鱼苗下塘：培育试验采用“半…     

鲈鱼幼鱼人工配合饲料中蛋白质,脂肪适宜含量的研究

探讨了人工配合料中蛋白质,脂肪对鲈鱼幼鱼生长的影响,对各试验组幼鱼肝组织中的脂肪含量进行了比较,经３５ｄ试验养殖,结果表明：鲈鱼幼鱼配合饲料中蛋白质和脂肪的含量分别为３９．８５％～４０．１２％和５．４％～１５．４％时较为适宜。     

草鱼的早繁及一年二次繁殖

通过温泉水培育亲鱼,使亲鱼在３月中旬批量繁殖,每千克雌鱼平均得苗２．５万尾,同批鱼又于４月中旬第二次繁殖,每千克雌鱼平均得苗３．６万尾,比同批亲鱼在自然水体中繁殖经济效益提高２．４倍。     

胶州湾菲律宾蛤仔的性腺发育

１９９６年４～６月,对胶州湾内的菲律宾蛤仔连续取样,将性腺用１０％福尔马林液固定,组织切片４～６μｍ,Ｈ．Ｅ染色,显微照相显示菲律宾蛤仔卵巢和精巢的发育是同步进行的,性腺在４月初开始进入繁殖初期的快速发育,４月中和４月底生殖细胞已明显增大,至５月上旬染滤已被成熟的生殖细胞充满,５月中旬前后生殖细胞被分批排放,５月下旬和６月上旬性腺进入休止状态,至此,形成了一个繁殖期,在繁殖期内,高龄贝比低龄贝发育     

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.