Edwardsiella tarda is one of the pathogenic bacteria of Paralichthys olivaceus that seriously affects the sustainable development of flounder aquaculture. In the present study, we used the family of high-quality flounder developed in 2012, 2013, and 2014 as the parents, and developed 28 flounder families in 2016, including 4 F3 generation families, 23 F4 generation families, and control family. After 60 days of growth trait assay and artificial bacterial infection experiments, seven families with strong resistance to disease (survival rate > 66％) were screened. F1639 was screened as the F4 generation family with enhanced disease resistance and fast growth rate. Furthermore, its survival rate was 77.23％, which was 32.75％ higher than that of the average of 28 families. The daily growth rate was 0.174 cm/d, which was 0.023 cm/d higher than that of the other 28 families. F1639 was derived from the 2007 (F0750, resistant to Vibrio anguillarum family), 2009 (F0927, resistant to V. anguillarum family), and 2014 (F1421, resistant to E. tarda family) families. The results showed that the disease resistance of the breeding families improved. Furthermore, the breeding ability of the offspring can be improved by the breeding of the family (the selection of compatriots). The present study has laid a foundation for breeding new variety of Japanese flounder with higher disease resistance and growth rate. Furthermore, it has important potential application in the genetic breeding for disease-resistant and fast growth stock in other fish species.

由于高密度工厂化养殖、海水污染等原因,牙鲆(Paralichthys olivaceus)养殖产业面临前所未有的危机,本研究以历年培育的抗病、速生牙鲆为亲本于2015年建立了57个家系,包括11个F3代和46个F4代家系.选择其中46个家系在146日龄和164日龄分别进行迟缓爱德华氏菌(Edwardsiella tarda)感染实验,配对样本t检验表明,两次实验无显著差异(P＞0.05).感染后的存活率分析表明,不同家系在抗迟缓爱德华氏菌的能力上存在显著差异(P＜0.05),从中鉴定出抗病力强的家系5个(F1551,F1503,F1501,F1550和F1505),其存活率均大于70％.根据46个家系的日增重率确定了4个快速生长家系(F1533,F1551,F1514和F1502),日增重率均大于0.225 0g/d.2015年牙鲆抗迟缓爱德华氏菌的抗病遗传力为0.177士0.020,为低遗传力,抗病性状选育适合家系选育.亲本抗病育种值变化范围为(-1.962士0.646)～(2.110±0.546),父母本育种值均较高的家系为F1551、F1550、F1501和F1505,其中,存活率最高的F1551家系的父母本育种值是所有家系父母本中最高的,表明具有良好抗病性能的F1551家系的父母本具有很好的育种性能.本研究通过家系选育、细菌感染实验及遗传参数和育种值分析,筛选出了抗病性强、生长速度快及父母本育种值高的家系,为培育抗病、生长快速牙鲆新品种提供了理论支持.

利用生物滤池模拟装置,以实际养殖废水为处理对象,探讨了4种常见有机碳源(葡萄糖、乙醇、红糖和淀粉)及不同碳氮比对有机物去除、硝化反应和异养反硝化作用等生物滤池主要净化过程的影响.碳源初选结果显示,同种碳源下,当C/N从0升高至6过程中,生物滤池对TAN(总氨氮)的去除率呈先升高后降低趋势;当C/N较小时,各组对NO2--N的去除率差异性不显著(P＞0.05),随着C/N继续升高,NO2-N去除率则显著降低(P＜0.05);乙醇组除外,其他3组随着C/N升高,CODMn去除率先迅速增大然后趋于稳定;各组NO3-N和TN去除率呈先升高后降低趋势,且变化显著(P＜0.05),当C/N=4时,分别达到最高值.碳源复选结果显示,在C/N=4条件下,分别添加有机碳源(乙醇、淀粉、红糖和葡萄糖)的4组对TAN、NO3--N、TN和CODM的去除率显著高于对照组(P＜0.05);而对照组NO2--N的去除率最高,达到93.59％;添加乙醇,生物滤池对水体中TAN、NO2-N、NO3-N和TN的去除效果优于其他3种碳源.研究表明,当C/N=4时,乙醇作为外加碳源能很好地提高生物滤池的净化效率.

Paralichthys olivaceus is the major species for marine aquaculture and fisheries on the western Pacific coast.Due to the high disease incidence and slow growth rate observed in artificial-breeding programs,the selective breeding of Japanese flounder has been pursued since the beginning of this century.Here,we established 52 F3 families based on the screened F1 and F2 core families that we bred previously.Approximately 196 days after&nbsp;hatching,we measured five growth traits of 1 560 fry from the 52 families,for a total of 7 800 data points.An “A-D”model and MINQUE were used to estimate the marginal mean,additive-variance component,dominance-vari-ance component,random-variance component,narrow-sense heritability,broad-sense heritability,parental additive effect and random hybridization effect of each trait.The additive-variance component ratios of the five traits were between (0.099±0.01)and (0.24±0.02);the dominance-variance component ratios were between (0.30±0.02) and (0.31±0.02);the random-variance component ratios were between (0.48±0.02)and (0.61 ±0.01);the narrow-sense heritabilities were between 0.099 and 0.24;and the broad-sense heritabilities were between 0.38 and 0.54.Each of these genetic parameters showed highly significant differences (p <0.01).The random dominance effects of 42 crosses were predicted,and D(2×6),D(2×18),D(3 ×4),D(7 ×12),D(7 ×14)and D(8×13)all showed highly significant positive effects (p<0.01)on the five traits.The results of this study provide a prelimi-nary set of optimal parental lines,crosses and families to establish improved Japanese flounder strains.These re-sults also provide a theoretical and technical foundation for further selective breeding.

为研究环境因子对生物膜水质净化效果,对爆炸棉为滤料的生物滤器进行了试验.采用优势菌种挂膜后,在不同水温、溶氧(DO)、盐度、pH条件下,研究生物滤器对人工加富的海水养殖废水水质的净化效果.结果显示,水温28℃时,化学需氧量(CODMn)、氨氮(NH4+-N)、亚硝酸盐氮(NO2--N)、磷酸盐(PO43--p)去除率分别为69.3％、93.7％、93.7％、19.4％;DO 6.00 mg/L时,CODMn、NH4+-N、NO2--N、pO4 3--P去除率分别为72.8％、91.7％、97％、15.6％;盐度25时,CODMn、NH4+-N、NO2--N、硝酸盐氮(NO3--N)、PO43--P去除率分别为57.1％、98.4％、99.9％、100％、42％;pH 7.5时,CODMn、NH4+-N去除率分别为72.8％、93.3％.研究表明,水温28℃、DO 6.00mg/L、盐度25和pH7.5为该生物滤器最适水质净化条件,此时生物膜净化效率较高,出水水质较好.

采用循环水养殖系统模拟装置,选择葡糖糖、乙醇、红糖和淀粉等4种碳源,按C(TOC)/N =4控制添加量,对不同碳源组和对照组(不添加碳源)牙鲆幼鱼的养殖效果进行比较.结果显示,牙鲆幼鱼经过40d的饲喂,对照组增重率最低,为104.0％,与乙醇组和葡萄糖组之间存在显著性差异(P＜0.05);各组存活率均超过85％;红糖组饵料系数略大于对照组,其它3组明显小于对照组;养殖过程中各组氨氮浓度均小于0.3 mg/L;硝酸盐氮浓度先升高后趋于稳定,稳定阶段对照组含量高于其它4组;添加少量可溶性有机碳源会导致养殖水体中有机物含量迅速升高,经过微生物分解利用短时间内又恢复正常.研究表明,向循环水养殖系统中添加适量有机碳源对牙鲆幼鱼的养殖效果起到促进作用.

A recent genetic linkage map was employed to detect quantitative trait loci (QTLs) associated with Vibrio anguillarum resistance in Japanese flounder. An F1 family established and challenged with V. anguillarum in 2009 was used for QTL mapping. Of the 221 simple sequence repeat (SSR) markers used to detect polymorphisms in the parents of F1, 170 were confirmed to be polymorphic. The average distance between the markers was 10.6 cM. Equal amounts of genomic DNA from 15 fry that died early and from 15 survivors were pooled separately to constitute susceptible bulk and resistance bulk DNA. Bulked segregant analysis and QTL mapping were combined to detect candidate SSR markers and regions associated with the disease. A genome scan identified four polymorphic SSR markers, two of which were significantly different between susceptible and resistance bulk (P = 0.008). These two markers were located in linkage group (LG) 7; therefore, all the SSR markers in LG7 were genotyped in all the challenged fry by single marker analysis. Using two different models, 11-17 SSR markers were detected with different levels of significance. To confirm the associations of these markers with the disease, composite interval mapping was employed to genotype all the challenged individuals. One and three QTLs, which explained more than 60 % of the phenotypic variance, were detected by the two models. Two of the QTLs were located at 48.6 cM. The common QTL may therefore be a major candidate region for disease resistance against V. anguillarum infection.

本研究从30个母系全同胞家系中各选取30尾牙鲆,28℃高温养殖40d,运用最小二乘法构建各牙鲆家系在高温下生长40d后的体质量(y)与初始的体质量(X)的回归方程,结果为:Y=2.433X+-5.539,(R=0.899),其中斜率的95％置信区间为1.973～2.892,截距的95％置信区间为0.909～10.169,并最终得到高温情况下各个家系增重情况的遗传力的估算值在0.15～0.38之间,属于中等遗传力.以牙鲆家系为材料进行了急性温度致死和慢性温度致死实验,实验结果表明:实验温度的选取在耐高温选育过程中至关重要,急性温度致死实验中(32℃)各家系均在58h左右死亡;而在慢性温度致死实验(31℃)中,各家系表现出了良好的耐热选择效应,死亡时间呈现了一定的连续性,各家系间耐热性差异极显著(P＜0.01).在31℃下,根据其热致死时间对其耐热性选择,最终选择2、11、19和36号家系作为耐热家系,为下一步耐热家系选育提供了基础群体.

Treatment and reuse of aquaculture wastewater is the key technology in recirculating aquaculture systems( RAS). Biofilter,a core unit in RAS,plays a vital role in removal of pollutants in aquaculture water. Water temperature,salinity,p H,dissolved oxygen( DO) and other environmental factors can affect the function of biofilter. Sudden changes of environmental factors can cause biofilm degradation or dropping off,which may seriously affect biofilter growth and water treatment effects. Biofilter efficiency can achieve the ideal state and aquaculture wastewater treatment effect be improved when the water temperature,salinity,p H and DO are well under control. It is necessary to study biofilter's kinetics of aquaculture wastes removal under each environmental factor,so as to provide a theoretical basis for optimizing design and operation management of RAS.

The present study aims to uncover the relationship between the phenotypic sex and genotypic sex and the growth rate of male and female half-smooth tongue sole and to select the excellent families with high female proportion.In this paper,we firstly established 22 half-smooth tongue sole families which were cultured in the same pond.Secondly,we identified the offspring's phenotypic sex and genotypic sex of 5 normal male families and 5 neo-male families.This study shows that there are significant differences not only in growth rate but also in proportion of male to female.Two fast-growing families(No.16 and No.61)whose relative weight gain rate were 0.81 g/d and 0.56 g/d and 4 relatively fast-growing families(No.21,No.28,No.57 and No.63),the relative weight gain rate ranges from 0.48 g/d to 0.53 g/d were selected;12 commonly-growing and 4 slow-growing families were selected also.The average ratios of genotypic female and phenotypic female of the 5 normal male(ZZ)families were 51.87% and 42.94%,and the ratio of genotypic female reversing to phenotypic male was 14.08%.Instead,the average genotypic female and phenotypic female ratio of the 5 neo-male(ZW)families was 49.34% and 4.45%,respectively,and the ratio of genotypic female reversing to phenotypic male was 91.41%.In the present study we found for the first time that there were significant differences in phenotypic sex ratio between different families.We also found that the genotypic females in neo-male families were more easily reversed to phenotypic males,which increased the number of phenotypic males in cultured populations.It initially showed that the families with high female proportion and fast growing rate could be selected via family selection,which could provide theories and new technical methods for the breeding and the production of high quality seeding of half-smooth tongue sole.

As an important mariculture species in China, the rapid development of breeding industry of Japanese flounder (Paralichthys olivaceus), lead to the breeding of Japanese flounder facing more and more serious prob-lems at present, such as growth rate depression, fertility declined, resistance recession etc. In order to keep Japa-nese flounder aquaculture developing healthy and sustainability, it is necessary to get fast-growing Japanese flounder by crossbreeding and selecting. In this paper, four base stocks of Japanese flounder (Paralichthys oliva-ceus), including Resistance stock (RS), Korea stock (KS), Resistance Japanese stock (RJ), Japanese Resistance stock (JR), were used to crossbreed and establish Japanese flounder families. The total length and body weight of these families would be measured, when they were about 19 months old. The SPSS system was used to analysis the data, at first. And then, estimated breeding values (EBVs) and other genetic parameters of total length and body weight were estimated by DMU package, based on the method of REML (Restricted Maximum Likelihood) and BLUP (Best Linear Unbiased Prediction) procedure. Results showed that, the phenotypic value of crossbreed-ing combination, KS (♂) × RJ (♀), was best among all the combinations. The heritabilities of Japanese flounder’s total length and body weight were 0.301 and 0.295, respectively, both of which were medium heritability. The correlations coefficient of breeding value and phenotypic value of growth traits were 0.838 and 0.827; both phe-notypes of total length and body weight were statistically highly significant (P<0.01) correlated to their breeding values, respectively. That is to say, the prediction result of breeding value reasonable accuracy was perfect. Com-paring the means of breeding value of all combinations, we selected KS as male and RJ as female to breeding new species, because the two has the best breeding value relative to sex. By this method, new Japanese flounder variety growing rapidly could be brood successfully.

Japanese flounder(Paralichthys olivaceus) is a widely cultured marine fish species in China and is highly valued because of its fast growth and good flavor. However, frequent occurrence of disease and subsequent losses limit profitability and aquaculture development. Breeding a new flounder strain with enhanced disease resistance is an important task in marine fish aquaculture. In the present study, new Japanese flounder families were established based on Japanese stock(JS), Korean stock(KS), and stock with high resistance to Vibrio anguillarum(RS) by nested hybrid, cross, and gynogenesis. Forty-three and sixty-five Japanese flounder families were established in 2009 and 2012, respectively. Disease resistance was investigated using 33 families in 2009 and 43 in2012 through intraperitoneal injection challenged with V. anguillarum. The results demonstrate that different families exhibited variable survival rates and 13 families with high disease resistance were obtained. All 13 families exhibited significantly higher survival rates compared with the control, however, some were more significant than others(P0.01 in 3 families; P0.05 in 10 families). Of these 13 families, three were derived from the F2family, one from the F3 family, and two belonged to the first and second gynogenesis generations(G1 and G2). In these six families, disease resistance was high in the parents, with the exception of the F2 family; their survival rate variation coefficients were 10%. Analysis of disease resistance in the three successive generations revealed that, 13 of the 16 disease-resistance families which included 13 families mentioned above and 3 resistant families sereened in 2007 were derived from RS. In conclusion, some F2, F3, G1, and G2 families exhibited enhanced disease resistance inherited from their parents, indicating that the establishment of a disease-resistant strain based on these families is possible.

Objective The purpose of the study was to sum up the culture techniques for turbot spawner and provide references for practitioners involved in turbot breeding. Method Effects of nutrition enhancement and controllable light and temperature on gonad development and egg quality were observed and studied via controlling light and temperature, feeding freezing-fresh fish and nutrition-enhanced bait. ResultThe day of gonad development of these spawners had moved up by 67 days, and the duration of gonad-development had been reduced by 9 days. Egg-laying duration was shortened by 18 days. The average egg amount was 867 mL. The zygote motility rate reached 80.1% with fertility rate of 67.3% and hatching rate of 61.9%. After further analysis, it was found that controlling light and temperature could remarkably move ahead gonad development by 60 days, and cut gonad development duration and egg-laying period to some extent. Nutrition enhancement could dramatically improve spawner fecundity, floating egg amount, floating rate, zygote motility rate and hatching rate. Spawner egg amount and weight as well as zygote motility rate and hatching were positively correlated. Conclusion Egg quality was improved signifi-cantly by nutrition enhancement and light and temperature control. The day of gonad development was moved up greatly, so off season spawning was realized.

In order to evaluate the effectiveness of selective breeding in Paralichthys olivaceus,we used the individuals from the first selected generation as parents and constructed 10 half-sib families and 20 full-sib families by artificial fertilization.The 4-month aged individuals were randomly selected from each half-sib family for growth parameter measurements.Variance analysis showed that the mean body weight of selected groups was 2.91 g heavier in the selected group,representing a 11.25% increase than that of wild control group.The difference was significant(p<0.05).The total length of the selected group was 1.33 cm longer in the selected group,showing a 10.36% increase than that of the control group,and the difference was highly significant(p<0.01).These results showed a high effectiveness of selection for growth traits in P.olivaceus.The estimated heritability of body weight,full length and body depth was 0.656~0.731,0.481~0.742 and 0.480~0.651,respectively.All these parameters belonged to the higher heritability,suggesting that the succeeding selection for these traits can still get a good genetic gain.

Artificial reproduction and rearing of Senegal sole, with brood stocks cultured from introduced hatchery-reared juveniles, were carried out from 2005 to 2006. During the two reproductive seasons, mature female fish were treated with intramuscular injection of luteinizing hormone releasing hormone (LHRH-a) to induce ovulation. 31 out of the 33 treated female fish ovulated normally after the administration of the hormone. 7.3×106 fertilized eggs in total were obtained through dry artificial fertilization method. The average fertilization ratio and hatching rate of fertilized eggs were 64.3% and 80.5%, respectively. A total of 2.49×106 juveniles at mean body lengths of 21 to 33mm, and 1.12×106 juveniles at mean body lengths of 22 to 36mm were produced in two hatcheries in 2005 and 2006, respectively. The survivorships of larvae during the two years were 62.7% and 58.2%, respectively. In this study, fertilized eggs of Senegal sole were obtained abundantly through artificial fertilization and more than a million juvenile fish in total were produced during each reproduction season in two hatcheries. Detailed description of the methods and techniques used in these hatcheries are presented in this paper.

This paper presents the results of large-scale seedling production of .Cynoglossus semilaevis. Gunther from 2003 to 2004 together with those key technologies like broodstock cultivation, egg incubation and larviculture were summarized These technologies were proved to be operative since a total of 2.7 millions of post larvae (Total length 30~40 mm) was obtained in the hatcheries of Laizhou, Jiaonan and Haiyang. Within these three hatcheries, the seedling cultivation density averaged 1 696, 1 985 and 2 050 per square meter, respectively in 2003 and 2004. The survival rates reached 20.2%、25.5%and 30.9%, respectively. This is the first record in China on large-scale (magnitude up to millions of level) seedling rearing of .Cynoglossus semilaevis. Gunther.

Temperature and salinity are two important factors for the fish fry breeding.In this paper,the embryonic development conditions of tongue sole(Cynoglossus semilaeusi Gunther) in different temperature and salinity conditions are studied.It is shown from the comparisons between hatch times,hatch rates,abnormal rates and activities in different conditions that temperature has significant effects on the hatch of fertilized eggs.The fish larvae cannot be hatched from the fertilized eggs at temperature below 18 ℃ or above 28 ℃,the fertilized eggs can be hatched at temperatures 18 ℃ to 28 ℃,the suitable hatch temperatures are 22 ℃ to 23 ℃,and the hatch time of fertilized eggs gradually decreased with increasing temperature.At water temperature of 23 ℃,the fish larvae cannot be hatched from the fertilized eggs in water with a salinity below 16 or above 48,the fish larvae can be hatched from the fertilized eggs in the salinity range of 18 to 46,the fish larvae were all abnormal in water with a salinity above 38,the salinity has no effect on the hatch time,and the suitable hatch salinity range is 28 to 32.

The varitions in activities of main digestive enzymes (acid protease,alkaline protease,amylase and lipase) and alkaline phasphatase in different development stages of tongue fish Cynoglossus semilaevis were determined.It is shown from the determined results that the activities of acid protease and alkaline protease in tongue fish can be detected in the early larval development stage,two extreme low alkaline protease activities were observed during the period of the first feeding and the transition from larva to juve-(nile),and the activity of acid protease increased obviously from the appearance of gastric gland(about the 23rd day after hatch).The noticeable amylase activity was exhibited in the early larval stage,the activity decreased drastically from the twelfth day after hatch,and then kept at a low specific activity level.The lipase activity kept at a low level in the early larval stage and then increased slowly after entering the juve-(nile) stage.After the metamorphosis was completed,the alkaline phosphatase activity increased rapidly,which indicates the maturity of enterocytes and the improvement of digestive mechanism of intestines.