乙醛、对苯二甲酸、乙二醇对四链藻生长的联合毒性

乙醛、对苯二甲酸、乙二醇等为化纤废水中的主要物质,其对四链藻生长影响的联合毒性实验结果表明,乙醛和对苯二甲酸（质量浓度比１：３０）,乙醛和乙二醇（质量浓度比１：１３５６）,对苯二甲酸和乙二醇（质量浓度比１：４）,乙醛,对苯二甲酸和乙二醇（质量浓度比为１：３０：１３５６）对四链藻生长影响的４８ｈＥＣ５０值分别为１９７．２１、８８０６．３、１１３４４．０７和９１２０．１ｍｇ／Ｌ,４种混合物对四链藻的联     

非离子态氨及酸碱度对鳜鱼种的毒性试验

采用静水试验法测定了非离子态氨对鳜鱼种的急性毒性及鳜鱼种对水质酸碱度的耐受性。非离子态氨对鳜鱼种２４、４８、９６ｈ的半数致死浓度（ＬＣ５０）分别为０．７６３、０．６６３和０．５２５ｍｇ／Ｌ;安全浓度为０．０５２５ｍｇ／Ｌ;鳜鱼种对ＰＨ值９６ｈ的耐受范围为４．１０－９．１０。     

非离子态氨及亚硝酸盐对欧洲鳗鲡的急性毒性试验

１９９７年６～８月,通过人工控制ＮＨ３－Ｎ及ＮＯ２－－Ｎ的浓度,对欧洲鳗鲡进行急性毒性试验的结果表明：非离子态氨对欧洲鳗鲡２４、４８、９６ｈ的半致死浓度分别为４．２６、３．２７、２．１９ｍｇ／Ｌ,安全浓度为０．２１９ｍｇ／Ｌ;亚硝酸盐对欧洲鳗鲡２４、４８、９６ｈ的半致死浓度分别为１００．０、８４．１、２６．６ｍｇ／Ｌ,安全浓度为２．６６ｍｇ／Ｌ。     

非离子氨氮对罗氏沼虾幼体的毒性研究

通过非离子氨氮对罗氏沼虾幼体的急性致毒试验表明：Ⅴ期幼体９６ｈ的半致死浓度（ＬＣ５０）值为１．１４ｍｇ／Ｌ,安全浓度（ＳＣ）值为０．１１ｍｇ／Ｌ;Ⅸ期幼体９６ｈ的ＬＣ５０值为１．４０ｍｇ／Ｌ,ＳＣ值为０．１４ｍｇ／Ｌ,建议在育苗期间加强水质管理,有效地控制水体中非离子氨氮的浓度。     

史氏鲟南移驯养及生物学的研究:Ⅱ.几种环境因子对仔鱼的影响

非离子氨对史氏鲟早期仔鱼７２和９６小时的ＬＣ５０分别为０６８和０６３ｍｇ／Ｌ;对晚期仔鱼的８、１２、１４、４８、７２和９６小时的ＬＣ５０分别为０５０、０４３、０３５、０２６、０２１和０１７ｍｇ／Ｌ,当浓度达到０３５ｍｇ／Ｌ时,在１７小时内造成试验鱼全部死亡。４８小时内造成早期仔鱼５０％死亡的总铁浓度为５００ｍｇ／Ｌ。史氏鲟仔鱼对ｐＨ忍耐性的上限和下限分别为９２５和３６０,立刻致死的ｐＨ值分别为２０９—２５０和１０１０—１０００。     

沼泽绿牛蛙蝌蚪对盐度和酸碱度的耐受性研究

通过沼泽绿牛蛙蝌蚪对不同盐度和酸碱度的需受性试验,得出沼泽绿牛蛙蝌蚪对盐度在２４、４８、９６ｈ平均忍受限（ＴＬｍ）分别为８１３、７５０、６３８ｇ／Ｌ,安全浓度为１９１ｇ／Ｌ;在ｐＨ值４２～１０５０,沼泽绿牛蛙蝌蚪至少可存活９６ｈ。     

红螯螯虾对盐度耐受性的研究

测定了红螯螯虾幼虾和虾苗对盐度的耐受性，虾苗２４ｈ，４８ｈ，７２ｈ，９６ｈ的ＬＣ５０值分别为１７７９‰，１６６９‰，１５１３‰，１３０２‰，安全浓度为４４１‰；幼虾２４ｈ，４８ｈ，７２ｈ，９６ｈ的ＬＣ５０值分别为１９５８‰，１８６１‰，１６４７‰，１５８８‰，安全浓度为５０４‰。     

澳大利亚红螯螯虾对水中氨氮浓度耐受性的研究

澳大利亚螯螯虾氨氮急性中毒试验的结果表明，在水温２１－２２℃，ｐＨ６．７－７．２时，该虾对水中氨氮浓度的耐受性为：４８小时的ＬＣ５０为１１８．０６ｍｇ／Ｌ，而且ＬＣ５０值随试验时间的延长而降低。     

K^＋,SO^2—4和碳酸盐碱度对大银于仔鱼存活的影响

本试验观察了Ｋ＾＋,ＳＯ＾２－４和碳酸盐碱度对大银鱼仔鱼存活的影响。大银鱼仔鱼在Ｋ＾＋浓度１０－３０２．４ｍｇ／Ｌ中９６ｈ成活率为９５－１００％,在ＳＯ＾２－４３８４－１９２０ｍｇ／Ｌ中９６ｈ成活率为１００％〉资助它们能正常生长,碳酸盐碱度低于１４ｍｅ／Ｌ时９６ｈ成活率为１００％,当碱度升到２２ｍｅ／Ｌ时其成活率为８０％。     

复合酚在渔业中的应用研究

测定了草鱼鱼种对复合酚的耐受性以及利用Ｋ－ Ｂ法在体外测定了复合酚对荧光假单胞菌和肠型点状气单胞菌的抑菌作用。结果表明, ２４, ４８, ７２ , ９６ ｈ 的ＬＣ５０ 分别为１９－３６ ×１０－６ , １８－３７ ×１０ －６, １７－５２ ×１０－６ ,１５－８１ ×１０ －６μＬ／Ｌ, 安全浓度为４－９６×１０－６μＬ／Ｌ。复合酚对荧光假单胞菌的抑菌作用明显, 最小抑菌浓度（ＭＩＣ）小于１２－５×１０－６ μＬ／Ｌ; 对肠型点状气单胞菌的抑菌效果不明显。     

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).