珠江斑Hu年龄和生长的研究

观察珠江斑Ｈｕ的胸鳍和鳃盖骨,研究其年龄特征、渔获物年龄组成和体长、体重组成,并对其体长与鳃盖骨长、体长与体重的关系,以及生长规律进行了分析。其年轮形成时间为１２月～翌年３月;体长与鳃盖骨长的关系式为Ｌ＝３４．７６Ｒ＋０．４５３３,体长与体重的关系式为Ｗ＝０．０３２Ｌ＾３．１８７２。生长Ｖｏｎ Ｂｅｒｔａｌａｎｆｆｙ方程分别为Ｌｔ＝１５６．７５「１－ｅ＾－０．０８９（ｔ－０．０１６８）」和Ｗｔ＝３     

黄颡鱼生长特征与食性的研究

本文研究了黄颡鱼的生长特征及食性，得到黄颡鱼体长与体重的关系式为Ｗ＝３．５７１×１０＾－４Ｌ＾２．３７９，体长生长方程为Ｌｔ＝２３７．００２（１－ｅ＾－０．２８０（ｔ＋０．１２７），主要食物为虾类，其次为小鱼、鱼卵等。     

三道河水库大眼鳜的年龄和生长

依据大眼鳜鳞片上的疏密切割等特征鉴定年龄。渔获个体以Ⅱ龄鱼为主占８６％。鳞长与体长关系Ｌ＝１２１３２６Ｓ１０５０８。体长与体重关系Ｗ＝１２３８×１０－２Ｌ３１９８９。体长、体重与年龄的关系适用ＶｏｎＢｅｒｔａｌａｕｆｙ生长方程拟合：Ｌｔ＝Ｌ∞（１－ｅ－０５０８３（ｔ－０３９９））；Ｗｔ＝Ｗ∞（１－ｅ－０５０８３（ｔ－０３９９）３１９８９。拐点年龄为２５６ａ，与生长指标陡然下跌年龄和性成熟年龄基本一致。为了资源的持续利用应限捕体重５３０ｇ、相应体长２８３ｃｍ以下个体     

金沙河水库乌鳢的年龄与生长

该水库乌鳢在４ ～６ 月形成年轮,鳞片上以环片的切割为主要年轮特征。渔获物以２ 龄个体为主,体长和体重关系式为 Ｗ ＝ ０ ．０２５０５ ×Ｌ２ ．８２３２ ,ｖｏｎ Ｂｅｒｔａｌａｎｆｆｙ 生长方程中主要生物学参数为：Ｌ∞＝ ６２ ．９６ｃｍ ,Ｗ∞＝ ３００６ ．２ ｇ,ｋ＝ ０ ．２７５０ ,ｔ０ ＝ ０ ．０１０８ ,ｔｉ＝ ３ ．８ ａ,Ｗｉ＝ ８７４ ．７ｇ 。总体上看,金沙河水库乌鳢的生长较慢     

史氏鲟南移驯养及生物学的研究 I.1龄鱼的生长特性

首次将史氏鲟从黑龙江南移至长江流域人工条件下驯养,培育成１龄幼鱼,１１月龄的个体最大值重为１０５３克,均重６０６克,最大体长８９８毫米,均长５６９毫米,幼鱼的最适生长水温为１９．８℃,在１７－２１℃水温条件下,生长迅速,１龄鱼全长与体重的关系式为Ｗ＝０．００１３０２Ｌ＾３．２２６８（ｒ＝０．９９９６）体重生长曲线公式为Ｗ＝６．７７７８９２ｅ＾０．３８５５ｔ（ｒ＝０．９９３５）。     

淤泥湖近太湖新银鱼的生长研究

对生活在湖北淤泥湖中的近太湖新银鱼进行了生长研究。结果为：①全长与体重的相关关系：Ｗ＝２．３１２×１０＾－６Ｌ＾３．００；②全长生长方程：Ｌｔ＝７２．３（１－ｅ＾－０．３（ｔ＾－０．１）），体重生长方程Ｗｔ＝０．８７３８（１－ｅ＾－０．３（ｔ＾－０．１））＾３。③Ｌ∞＝７２．３（ｍｍ），Ｗ∞＝０．８７３８（ｇ），ｋ＝０．３ｔ＝０．１，拐点年龄ｔｉ＝３．７月龄，拐点体重Ｗｉ＝０．２５ｇ。     

长江口花鲈的生长和食性

花鲈为沿海及河口的经济鱼类，亦可溯河生活于淡水。在长江口水域，花鲈属中型鱼类，其体长和体重的相关关系式为：Ｗ＝０．０６０５Ｌ＾２．６３４６（ｒ＝０．９８７８），生长方程为：Ｌｔ＝１００．９９５７［１－ｅ＾０．１７６８（ｔ＋０．７６３３）］，Ｗｔ＝１１５４２．２６［１－ｅ＾－１７６８（ｔ＋０．７６３３）］＾２．６３４６，体重生长拐点ｔｒ＝４．７龄，拐点处体重为３２８１．４克。早期幼鱼以浮游动物为食，     

史氏鲟南移驯养及生物学的研究 Ⅰ.1龄鱼的生长特性

首次将史氏鲟从黑龙江南移至长江流域人工条件下驯养,培育成１龄幼鱼,１１月龄的个体最大体重为１０５３克,均重６０６克;最大体长为８９８毫米,均长５６９毫米。幼鱼的最适生长水温为１９．８℃在１７—２１℃水温条件下,生长迅速。１龄鱼全长与体重的关系式为Ｗ＝０．００１３０２Ｌ３．２２６８（ｒ＝０．９９９６）,体重生长曲线公式为Ｗ＝６．７７７８９２ｅ０．３８５５ｔ（ｒ＝０．９９３５）。     

珠江斑Huo年龄和生长的研究

本文研究了珠江斑Huo胸鳍和鳃盖骨的年龄特征、渔获物年龄组成和体长、体重组成,并对其体长与鳃盖骨长、体长与体重的关系,以及生长规律进行了分析。鳃盖骨是年龄鉴定的最佳材料,年轮形成时间为12－2月;体长与鳃盖骨长的关系式为L=34.76R 0.4533,体长与体重的关系式为W＝0.032L^3.1872。生长适合于Von Bertalanffy方程,分别为Lt=156.75[1-e^-0.089(t-0.0168)]和Wt=31193.1793[1-e^-0.089(t-0.0168)]^3.1872。文中讨论了年轮形成原因和生长特性,同时对合理利用自然资源和生产养殖提出了某些建议。     

黑龙江的鳜鱼

本文研究了黑龙江水系鳜鱼的年龄与生长、产卵繁殖．食性等生物特性。通过鳃盖骨上形成的年耗测定年龄和推算：Ｌ１＝１３．１ｃｍ；Ｌ２＝２２．６ｃｍ，Ｌ３＝２９．１ｃｍ……Ｌ１２＝５３．９ｃｍ。体重与体长相关式为，Ｗ＝０．０３６０４Ｌ２．８８１１，ｒ＝０．９９８。根据Ｖｏｎ．Ｂｅｒｔａｌａｎｆｆｙ生长方程理论公式拟合的生态学参数：Ｌ８＝６２．８ｃｍＷ８＝５８１７ｇ；ｔ０＝－０．１２，Ｋ＝０．１７：ｒ＝０．９９５；ｔｉｐ＝６．３龄，ｔｍａｘ＝１７．５龄。黑龙江鳜鱼的生殖期为每年６月中旬至７月末，成熟个体的成熟系数：雌体平均为５．５８±１．９７；雄体体平均为２．１２±０．３８，生殖后的成熟系数，雌体平均为１．６０；雄体为０．７１。３０—６０ｃｍ体长的怀卵量平均为１８４０９７粒，卵径为１．３５ｍｍ。鳜鱼的食供，解剖２７尾胃中有食的标本，有８种鱼类和１种虾。１９８４年与１９６３年相比，黑龙江鳜鱼的资源量出现衰退趋势。     

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.     

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).