铬盐对鲤生长和饲料转化率的影响

以０．５ｍｇ／ｋｇ铬盐饲料饲喂１龄鲤６５ｄ和３月龄鲤３０ｄ,相对生长率分别提高１３．７９％和２０．６９％饲料转化率提高２１．８３％和２６．０％。表明铬盐有促进鱼类生长作用和提高饲料转化率的效应,而铬盐对鱼体营养成分的作用不明显。但铬盐对对高血糖症鱼的作用是低剂量各（２．５μｇ／ｋｇ体重）使血糖明显下降,高剂量（６０μｇ／ｋｇ体重）则使血糖明显升高;铬盐含量０．５ｍｇ／ｋｇ饲料使高血糖症鱼的血糖下降     

5种常见鱼药治疗剑尾鱼聚缩虫病的研究

用５种药物治疗剑尾鱼聚缩虫病试验，结果呋喃唑酮无效，硝酸亚汞（１． ２５ ±０． ２５） ｍｇ／Ｌ、硫酸铜酸亚铁（５：２）合剂（８．５±０．５）ｍｇ／Ｌ、甲醛（３０±５）ｍｇ／Ｌ、孔雀石绿（０． ９ ± ０． １） ｍｇ／Ｌ对聚缩虫杀死率均在 ９５％以上；治愈率依次为：（９２．５ ± ２．５）％、１００％、（８７．５±２．５）％、（８２．５±２．５）％；剑尾鱼对药物的敏感性强度为孔雀石绿＞硝酸亚汞＞硫酸铜合剂＞甲醛，安全浓度依次为：０．３２、０．４８、４． １、９．４ ｍｇ／Ｌ。表明治疗剑尾鱼聚缩虫病用硫酸铜合剂（８． ５ ± ０． ５） ｍｇ／Ｌ、甲醛（３０ ± ５） ｍｇ／Ｌ浸泡效果好。     

莺河一库渔业潜力及开发对策

对莺河一库水质的调查分析和饵料生物的定量测定得出：该库属中营养型水库，浮游植物初级生产力平均２３．９６ｋｇＯ＿２／ｈａ·ｄ，其中鱼类生长期内初级生产力３２１．１６ｋｇＯ＿２／ｈａ·ｄ，净生产量２５．７３ｋｇＯ＿２／ｈａ·ｄ，净生产量之和为５４０３．３ｋｇＯ＿２／ｈａ，折合浮游植物鲜重为２８６３７．５ｋｇ／ｈａ；浮游植物、浮游动物和底栖动物的生物量分别为３．２ｍｇ／Ｌ、１．２６ｍｇ／Ｌ和０．８５ｇ／ｍ￣２，水库近期鱼产力为３６３．６ｋｇ／ｈａ，总产量２０．９４万ｋｇ。该库历年平均成鱼单产为８８．４ｋｇ／ｈａ，占估算鱼产力的２４．３％，水库的渔业潜力有待开发利用，因此，提出了今后合理开发水库渔业资源的对策。     

常见水产动物疾病的中草药防治方法介绍（下）

（三）真菌病的防治１－水霉病的防治（１）每亩用菖蒲２－５～５ｋｇ，食盐０－５～１ｋｇ，加入人尿２～５ｋｇ，全池泼洒。（２）用五倍子全池泼洒，使池水呈４ｍｇ／Ｌ浓度。（３）桐树叶（或芝麻秆）扎成小捆，放入池中。（４）用２～４ｍｇ／Ｌ的烟茎浸出液，浸洗病鱼３０分钟。（５）全池泼洒２ｍｇ／Ｌ苦楝和０－４ｍｇ／Ｌ碳酸钠。２－鳃霉病的防治用１００ｋｇ芭蕉心（大蕉心或香蕉心）切碎加食盐３～４ｋｇ，再加乐果１００ｇ拌匀，上食台投喂，每１００ｋｇ鱼喂上述混合饲料５ｋｇ，效果较好。（四）寄生虫病的防治１－车轮虫病…     

湖泊网箱养殖名优鱼高产技术研究

１９９８￣１９９９年，在沅江市榨南湖渔场的榨南湖水域，开展了湖泊鳜鱼、草鱼、团头鲂、湘鲫等名优鱼网箱养殖。１９９８年，７０只网箱总产商品鲁６０５３３ｋｇ，平均净单产３０．９ｋｇ／ｍ＾２，产值３６５．２元／ｍ＾２，利润１３４．５元／ｍ＾２，投产比１：１．５８；１９９９年，９０只网箱总产商品鱼１１１１４９ｋｇ，平均净单产３６．７ｋｇ／ｍ＾２，产值４４５．１元／ｍ＾２，利润１５１．２元／ｍ＾２，投产比１     

湖泊网箱养殖名优鱼高产技术研究

１９９８￣１９９９年，在沅江市榨南湖渔场的榨南湖水域，开展了湖泊鳜鱼，草鱼、团头鲂，湘鲫等名优鱼网箱养殖。１９９８年，７０只网箱总产商品鱼６０５３３千克，平均净单产３０．９ｋｇ／ｍ＾２，产值３６５．２元／ｍ＾２，利润１３４．５元／ｍ＾２，投产比１：１．５８；１９９９年，９０只网箱总产商品鱼１１１１４９ｋｇ平均净单产３６．７ｋｇ，产值４４５．１元／ｍ＾２，利润１５１．２元／ｍ＾２，投产比１：１．５１     

乳山湾海水,底质及贝类体内砷的研究

通过１９９５年６－９月对乳山湾的综合调查，初步摸清了乳山湾海水，底质及贝类体内砷的分布。该水域内砷的浓度范围为０．７２－６．８０μｇ／Ｌ，其平均值为１．９４μｇ／Ｌ；底质中砷的含量范围为５．０－９．６ｍｇ／ｋｇ，平均值为７．７７ｍｇ／ｋｇ；     

北民湖自然资源的调查及渔业开发初探

１９９０年，调查了北民湖（１４６７ｈｍ２）的水质，水生生物等情况，该湖氮、磷营养缺乏（ＴＮ１．１８３０ｍｇ／ｌ，ＴＰ０．０２０１５ｍｇ／ｌ），ＴＮ∶ＴＰ＝５８．７１∶１，为浮游生物生长限制因子，折算产鱼潜力为３１．６２ｋｇ／ｈｍ２，通过人工定点施化肥，使其ＴＮ，ＴＰ达到２．０５８４ｍｇ／ｌ，０．２１４５ｍｇ／ｌ，ＴＮ∶ＴＰ＝９．６∶１，投放鱼种３７．５ｋｇ／ｈｍ２，年产鱼２８４．０４ｔ，折合１９３．６ｋｇ／ｈｍ２，为１９８９年鱼产量２８．６４ｋｇ／ｈｍ２的６．７６０倍。     

洪门水库渔业资源调查报告

洪门水库为江西第二大水库，可养鱼面积７．６５万亩，消落区面积２－３万亩，浮游植物生物量４．４０６ｍｇ／Ｌ，浮游动物生物量２．４５ｍｇ／Ｌ。初步估算，水库鱼产力在３１．３６ｋｇ／亩，而目前单产水平保持在１６．６ｋｇ／亩上下。渔获量以镛鱼为方，鲢鱼次之。全库鱼类９６种，经济鱼类占８５％，如适度开发，水库鱼产力将明显提高。     

南方大口鲶商品鱼养殖技术

南方大口鲶属鲶形目、鲶科、鲶属,主要分布江河水系,常见个体３－５ｋｇ,最大个体５０ｋｇ,为广温性凶猛鱼类,生活水温０－３８℃,适宜生长水温１８－３２℃,ＰＨ值范围６－９,最适７－８４,耐低氧能力较强,水中溶氧３ｍｇ／Ｌ能正常生长,低于２ｍｇ／Ｌ出现浮头,１ｍｇ／Ｌ造成大批死亡。南方大口鲶生长快、适应性广、肉质嫩、味道美、营养丰富,是一种大型优质经济鱼类,深受消费者亲睐,因而被在面积推广养殖。现将其商品鱼殖方法简介如下,供参考。１　池塘养殖１．１　池塘条件主养南方大口鲶的池塘,面积５００－１５０…     

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.