Acoustic Conditioning System Development and Conditioning Experiments on Black Seabreams in the Xiangshan Bay Sea Ranch

Attracting released hatchery-reared fish to designated areas during the growth process is vital to realize the objectives of sea ranching. Based on the bottom artificial reefs and surface kelp culture facilities in the Xiangshan Bay sea ranch, we proposed systematic techniques related to acoustic conditioning of the black seabream(Sparus macrocephalus). Experiments conducted in 12 m × 10 m × 1.6 m ponds on Xixuan Island showed that black seabream was positively sensitive to 500–600 Hz periodic signals. Conditioned responses were apparent after 8 d. Two to three days were required for recovery of the memory of a conditioned response after a 20-day interval. According to the practical application requirements in the open sea, unattended acoustic conditioning equipment was developed. The ranching equipment was used in 12 m × 12 m × 2.5 m cages, and the behavior of black seabream juveniles was successfully guided after 7 days. Of the 16000 released fish, 82.5% of them were conditioned with a flexible grading net. To avoid inducing a stress response, the juveniles were released into the sea ranch in situ from the net cage. The acoustic conditioning equipments were moved into the open sea and the aggregation phenomenon of the released fish was observed when the sound was played. After 6 months of investigation and based on Sr+ marking, only one acoustically conditioned fish was found outside the 3.5-km^2 sea ranch area, thereby reached the goal of guiding activity. The practical effect in the Xiangshan Bay sea ranch showed the validity of the acoustic conditioning system, which may contribute to improve the operation of the sea ranches in the East China Sea.

Full-length transcriptome sequence and SSR marker development for genetic diversity research in yellowfin seabream Acanthopagrus latus

Yellowfin seabream Acanthopagrus latus is an important economic fish in Chinese coastal areas.Given its narrow distribution and overfishing,the genetic diversity of yellowfin seabream has been restricted for artificial breeding and reproduction.We performed full-length transcriptome sequencing and assembly of the genome of yellowfin seabream.A total of 68086 unigenes were obtained,with an N50 of 3391 bp on average length of 2933 bp.A total number of 50593 expressed sequence tags linked to simple sequence repeats(EST-SSR)were identified,among them dinucleotide repeats(40.6%)and AC/GT motifs(38.5%)were the most frequent.Of the 190 EST-SSRs for which PCR primer pairs were designed,150 primer pairs successfully amplified target loci and 15 SSRs showed high polymorphism.The alleles per locus ranged 6-50 on average of 25.3.The expected and observed heterozygosity varied from 0.632 to 0.969 and from 0.519 to 0.953,respectively.The polymorphic index content(PIC)values of each locus ranged 0.587-0.966 on average of 0.851.Among six yellowfin seabream population samples preliminarily tested for genetic diversity and differentiation,the Fangchenggang(FCG)population in Guangxi Province had the highest mean observed heterozygosity(H_(o))value(0.786),whereas the Zhangzhou(ZZ)population in Fujian Province had the lowest(0.678).The pairwise fixation index(Fst)values indicated significant population differentiation among six yellowfin seabream populations.This study provided evidence for the usefulness of the transcriptomic resource information and EST-SSR markers for natural resource conservation,population genetics,and breeding studies of yellowfin seabream in South China.

Reproductive Biology of the Striped Seabream Lithognathus mormyrus （Linnaeus, 1758） from AI-Haneah Fishing Site, Mediterranean Sea, Eastern Libya

Reproductive biology of L. mormyrus was studied using monthly samples totaling 224 fish obtained from AI-Haneah fishing site, eastern Libya Mediterranean Sea. Lengths of the examined fish ranged between 11.5 cm and 23.4 cm. Corresponding weights were 24.5 g and 160.8 g. The minimum values of the condition factors, KF and Kc, were 1.38 and 1.21 at the average fish length of 12.4 cm. These values increased with increases in length until they reached maximum values of 1.59 and 1.41 at the length of 22.1 cm. The high values of KF and Kc, Gonado-Somatic Index and oocyte diameter maintained during May, June, July, and August and the monthly changes in gonadal condition, indicated that summer was the breeding season of L. mormyrus. The oocyte diameter ranged between 379± 25.3 μ and 1,511 ± 143.3μ （n = 76） with an average of 895 ± 111.3 μ. The sex ratio was in favor of females during all months of the study. The overall sex ratio was 1 ： 1.52. Length at first maturity, Ls0, for L. mormyrus was found to be 14.15 cm for males and 14.45 for females. Overall average of absolute fecundity was 4,342±557 egg per fish （n = 45）. The overall average of relative fecundity was 234± 181 egg per cm. Absolute fecundity increased with increasing fish length.

EFFECT OF ARTIFICIAL REGULATIONS OF ARTEMIA n-3 HUFA CONTENT ON GROWTH AND SURVIVAL OF BLACK SEABREAM (SPARUS MACROCEPHLUS) LARVAE

The requirement for dietary n-3 HUFA (highly unsaturated fatty acid ) for growth and survival of black seabream (Sparus macrocephalus) larvae was tested using Artemia with various levels of n-3 HUFA. Four tueatments with Artemia differing in theirn-3 HUFA were prepared by feeding them various oil emulsions .The results indicated that dietary n-3 HUFA significantly influences fish n-3 HUFA levels and are necessary for good growth and survival of black seabream larvae . The proper value of n-3 HUFA level and DHA, EPA level in Artemia should be 4.273% and 0.873% (wet weight) for good growth and survival in black seabream larvae respectively.

Influence of fish meal quality on growth,feed conversion rate and protein digestibility in shrimp (Penaeus chinensis ) and red seabream (Pagrosomus major)

The effect of fishmeal quality on growth,feed conversion ratio and protein digestibility was studied in a growth experiment with shrimp and red seabream.The shrimp and fish were fed three diets varing in the quality of the fishmeal used in the respective feeds: low quality fish meal,good quality fish meal,and Peru fish meal.The experiment lasted for 2 months.The shrimp and fish fed the feed with good quality fish meal showed significantly better feed conversion ratio,weight gain rate,protein digestibility than the other groups.

Evolution of sex ratio and egg production of gilthead seabream(Sparus aurata)over the course of five reproductive seasons

Spawning performance-relative fecundity and fertilization success-was studied in two hatchery-reared broodstocks of gilthead seabream(Sparus aurata)held under relatively constant well-water temperature(18-20◦C)and simulated natural photoperiod,for five consecutive spawning seasons,between 3 and 7 years of age.The spawning season lasted between 4 and 6 months each year,and the total number of eggs produced annually ranged between 1480000 and 3100000 eggs/kg female body weight,being the highest during the first and second spawning season.No difference was observed in monthly relative fecundity between years-although high variation existed within years,whereas fertilization success was the highest during the second and third reproductive season,and dropped significantly during the last year of the study.The male percentage of the broodstocks was 35%during the first spawning season of the females,and thereafter it decreased further and remained stable at around 15%-20%for the second and third spawning season.Substitution of older females with smaller males to readjust male percentage to 50%in the fourth spawning season,was followed by sex change of larger males to females and a drop of the male percentage to 18%in the following spawning season.The present study demonstrated the long spawning season of gilthead seabream-especially under constant water temperature,the high fecundity and fertilization success,and the stabilization of male percentage to~20%after the first spawning season or when a broodstock is modified to increase male percentage.These results are useful to the aquaculture industry,demonstrating that there is no need to add males to gilthead seabream broodstocks over the years,as the sex ratio is stabilized and egg production and fertilization success remain high with a relatively low male:female sex ratio.

Movement pattern of red seabream Pagrus major and yellowtail Seriola quinqueradiata around Offshore Wind Turbine and the neighboring habitats in the waters near Goto Islands, Japan

We investigated movement pattern of commercial important fish around Offshore Wind Turbine(OWT)and neighboring habitats in Goto Islands.We tagged 55 individuals of 2 fish species and released around the OWT in 2017.(27 Pagrus major from 1st Feb 2017 to 16th Mar 2017(winter),8 P.major and 20 Seriola quinqueradiata from 13th July 2017 to 13th Oct 2017(summer)).Acoustic receivers were deployed at OWT,south artificial reef(AS),trapnet(TN),north FAD(F1)and south FAD(F2)in winter and two more receivers were deployed at north artificial reef(AN)and natural reef(NR)in summer.We observed 12 P.major at OWT for a day after released in winter,majority of fish(13 individuals)were detected at TN.In summer,7 P.major were observed at OWT,1 visited TN within the day,but others disappeared.Ten S.quinqueradiata stayed at OWT longer than P.major after released and disappeared within 2 days.They mostly moved around AS,AN,NR.Residence time from K-M curve was 10 days for P.major in winter,a day in summer and 3 days for S.quinqueradiata.Both species showed low affinity for OWT as recorded low residency index despite the season.

黑鲷幼鱼同生群内不同增重性能子群间背肌质构和脏器生理的差异

根据黑鲷(Sparus macrocephalus)幼鱼同生群内不同增重性能子群间背肌质构和脏器生理的差异,揭示增重性能与机体代谢和取食运动对策与机制间的相关性,对于精准遴选黑鲷幼鱼优质增殖群体和科学指导黑鲷幼鱼高效集约化养殖具重要现实意义。任选西沪港海区板式网箱养殖的黑鲷同生群幼鱼3000尾,停食暂养1d后,按体质量由大到小依次分为A[体质量(8.2±1.5)g,出现率5%]、B[体质量(5.3±0.9)g,出现率20.6%]、C[体质量(3.8±0.6)g,出现率48.3%]、D[体质量(2.4±0.4)g,出现率21%]、E[体质量(1.7±0.5)g,出现率5.1%]等5个子群。在测量并统计背肌质构和脏器质量比例的基础上,较系统开展了不同增重性能子群间耗氧率、窒息点及鳃组织和内脏相关功能酶活力的差异。结果表明:(1)根据脏器比例性状的聚类特征,可较清晰地区分本研究所涉及的各个子群;(2)背肌质构性状和耗氧率性状中随增重性能增强呈单调增加的仅为耐咀性和日均耗氧率,耗氧昼夜节律除C子群呈昼均≈夜均(P>0.05)外,其余子群均呈夜均>昼均(P<0.05);(3)窒息点水中含氧量随增重性能增强呈阶梯式下降趋势,其中与E子群窒息点水中含氧量具显著差异(P<0.05)的仅为A、B子群,呈E>A≈B;(4)内脏淀粉酶、蛋白酶及AKP、ACP和ATP活力随增重性能增强均呈阶梯式下降趋势,SOD、CAT和POD酶活力均呈阶梯式上升趋势,而脂肪酶和LDH酶活力则均呈先降后升趋势;(5)鳃组织SOD、POD、Na^(+)/K^(+)-ATPase和Ca^(2+)/Mg^(2+)-ATPase酶活力均随增重性能增强呈阶梯式上升趋势,CAT酶活力则呈先降后升趋势。研究结果可为黑鲷生长性能评价体系构建、速生种质发掘和指导速生品种(品系)选择育种提供科学依据。

饥饿与再投喂对黑鲷幼鱼体质量变化、生化组成及肝脏消化酶活性的影响

在室内水温23-26℃的条件下,分别对黑鲷（Acanthopagrus schlegeli）幼鱼进行不同时间的饥饿（0d、3d、5d、10d、15d、20d）处理和饥饿20d后的恢复投喂（3d、5d、10d、15d）实验,每个处理组各设3个重复,分别测定其体质量、肥满度、肝体指数、肌肉与血清主要生化组成以及肝脏消化酶活性的变化。结果表明：1）在饥饿过程中,黑鲷幼鱼体质量、肥满度、肝体指数均显著性下降（P〈0.05）;恢复投喂后,三者均有不同程度的恢复。2）肌肉脂肪含量在饥饿3d时即表现出下降趋势,但在随后的饥饿时间里,肌肉脂肪含量的下降趋势并不明显（P〉0.05）,而肌肉蛋白含量在饥饿5d以内也无明显的变化,至10d时才出现显著性的降低。但随着饥饿时间的延长,肌肉蛋白含量均显著降低（P〈0.05）。恢复投喂第10天时,肌肉中的各项生化指标基本恢复至饥饿前水平。由此推测,饥饿胁迫下黑鲷是先动用了体组织的脂肪,而后再利用蛋白质且主要靠消耗蛋白质来满足维持生命活动所需的能量。3）血清中总蛋白、血糖、甘油三酯、胆固醇在饥饿阶段显著下降（P〈0.05）,恢复投喂第5天时,各指标均已基本回升到饥饿前水平。相比之下,血糖水平的恢复较快,随后逐渐趋于平稳。4）肝脏中类胰蛋白酶和脂肪酶的活性在饥饿阶段呈上升趋势,恢复投喂后则有所下降。淀粉酶活力在饥饿过程中呈下降趋势,恢复投喂后有所回升,但在整个实验期间淀粉酶活性并无显著性的变化（P〉0.05）。

饲料中添加氧化鱼油对黑鲷幼鱼生长的影响

研究了饲料中添加氧化鱼油对黑鲷(Acanthopagrus schlegeli)生长性能、脂质过氧化及肝组织结构的影响。分别以新鲜鱼油(过氧化物值POV,1.27 meq O2.kg-1油)与氧化酸败鱼油(POV,45 meq O2.kg-1油)为脂肪源配制等蛋等能的两种配合饲料,投喂平均体重18.9 g的黑鲷幼鱼9周。结果显示,氧化鱼油显著降低了黑鲷幼鱼的增重率(WG)、饲料效率(FE)及蛋白质效率(PER)(P<0.05)。饲料中添加氧化鱼油导致鱼体蛋白质含量极显著降低(P<0.01)、肝脏与肌肉中脂肪含量显著升高(P<0.05),而对鱼体、肝脏及肌肉中的水分及灰分含量无显著影响(P>0.05)。氧化鱼油组肝脏中脂质过氧化产物丙二醛(MDA)含量显著高于对照组,而维生素E含量则显著低于对照组(P<0.05)。饲料中添加氧化鱼油显著影响黑鲷肝脏内主要抗氧化酶活性,氧化鱼油组肝脏中超氧化物歧化酶(SOD)与过氧化氢酶(CAT)活性显著高于对照组(P<0.05);组织学结果显示氧化鱼油组肝脏出现明显病变,细胞核多集中在肝细胞边缘,肝细胞变大。统计分析表明,氧化酸败油脂显著降低了黑鲷的生长性能,加重了组织中脂质过氧化的程度,并导致肝脏组织发生病变。

真鲷仔稚鱼微粒饲料中DHA与EPA最佳比例的研究

制备4种n-3HUFA含量相同 ,DHA和EPA含量比(m(DHA)∶m(EPA))分别为1.70∶1 ,2.00∶1,2.30∶1和2.60∶1的微粒饲料 ,探讨DHA与EPA的配比对真鲷 (Pagrusmajor)仔稚鱼生长、存活和体内相关成分的影响。30d的养殖试验结果表明 ,m(DHA)∶m(EPA)≥2.30∶1的2种微粒饲料与m(DHA)∶m(EPA)≤2.00∶1的2种微粒饲料相比 ,真鲷仔稚鱼的生长速度和成活率 ,前者明显优于后者。该比例即m(DHA)∶m(EPA)≥2.30∶1应是真鲷微粒饲料中DHA与EPA的最佳配比。养殖试验结束后 ,对仔稚鱼体内相关成分的分析结果表明 ,仔稚鱼体内DHA的含量随微粒饲料中DHA含量的增加而增大。

饵料蛋白能量比对黑鲷幼鱼生长和体成分的影响

取黑鲷(Sparusmacrocephalus)幼鱼960尾,体重(3.39±0.18)g,以鱼粉和豆粕作为蛋白源,鱼油和豆油等比例混合油作为脂肪源,共配制4个蛋白水平(34%、38%、42%、46%),每一蛋白水平设3个脂肪水平(10%、13%、16%),共12种饵料,糖水平保持在16%左右,饵料的蛋白能量比(P/E)在96.76～136.21mg/kcal。黑鲷幼鱼随机分成12组,每组设2重复,实验为期42d。结果表明,对特定生长率(SGR)与饵料系数(FCR)的影响,以较高蛋白组(38%、42%、46%)显著优于低蛋白组(34%)(P<0.05),中、高脂肪组(13%、16%)显著优于低脂肪组(10%)(P<0.05);各组饵料对成活率的影响无显著差异(P>0.05)。当蛋白水平为42%,脂肪水平为16%时,黑鲷幼鱼获得最大特定生长率(3.20)、最高蛋白质效率(2.10)和最小饵料系数(1.14)。全鱼脂肪含量随着饵料中脂肪水平的提高而逐渐升高。在同一饵料蛋白水平内,全鱼蛋白与灰分含量随着饵料脂肪水平的提高呈逐渐升高趋势。经统计分析,饵料中不同蛋白能量比显著影响黑鲷幼鱼生长(P<0.05),饵料中脂肪有明显节约蛋白质的作用(P<0.05)。由生长及体成分的实验结果得出,黑鲷幼鱼的最适饵料蛋白水平为42%,最适蛋白能量比(P/E)为110.37mg/kcal。

真鲷野生群体和人工繁殖群体的同工酶遗传差异

采用水平淀粉凝胶电泳技术对采集于黄海海州湾海域的真鲷野生群体和经过 2代人工繁育的养殖群体进行了同工酶遗传变异研究。分析检测了 2个群体各 50个样本肌肉和肝脏组织的 1 3种同工酶共 2 0个基因位点 ,其中MDH_a、GPI、PGM等 1 0个位点为多态位点 ,ME和EST_b为变异程度比较高的位点。野生群体和人工繁殖群体的多态位点比例分别为 45%和 2 5% (P0 .95) ;群体平均观察杂合度分别为 0 .1 41± 0 .0 4 4和 0 .0 95± 0 .0 4 3。结果表明 ,真鲷的野生群体和养殖群体拥有较高程度的遗传变异水平 ,但是养殖群体的遗传变异水平比野生群体有一定程度的降低。养殖群体遗传变异水平的降低在一定程度上是由于亲鱼数量少所致。比较了同工酶分析和RAPD分析的结果。将此两种技术相结合在鱼类群体遗传多样性分析中具有比较实际的意义。

苯并(a)芘致毒的鱼的分子生态毒理学指标研究

通过测定典型的多环芳烃类物质苯并（a）芘（BaP）致毒后鱼体内几种重要分子生态毒理学指标的变化，来反映苯并（a）芘致毒对鱼体的影响．结果表明，肝脏ATPase活性降低，GST活性升高，DNA加合物相对标记水平（RAL）也增大，而EROD活性没有明显改变．这说明苯并（a）芘致毒对鱼体正常生命活动产生了重大影响，并具有潜在的致癌性．

土霉素在黑鲷体内的药物代谢动力学研究

首次报道了黑鲷口服土霉素的药物代谢动力学特征。用高效液相色谱法测定组织中的药物含量 ,药物在肌肉、血液、肝脏中的平均回收率分别为 85.61%、85.38%、82 .0 0 % ,该方法的检测限可达 0 .0 1μg/g。黑鲷 1次口服剂量为 75mg/kg的土霉素后 ,其血液药物浓度 -时间数据符合一室开放动力学模型 ,吸收速率常数 ( ka)为 0 .2 96/h、达峰时间 ( Tmax)为 10 .635h、峰浓度 ( Cmax)为 1.398μg/ml、分布半衰期 ( T1/2α)为 2 .339h、消除半衰期 ( T1/2β)为 4 6.663h,药时曲线下面积 ( AUC)为110 .2 5mg/L· h。黑鲷口服药物 0 .5h后在血液、肌肉、肝脏、肾脏 4种组织中就可以检测到药物的存在 ,药物在 16h的采样点浓度达最高 ,分别为 1.68μg/ml、1.68、2 .52、6.77μg/g。

真鲷的营养需要及配合饲料的研究初报

本文综述了真鲷的营养需要，研究了不同植物蛋白源对真鲷生长的影响，并在此基础上设计了三种饲料配方，试验结果表明Ⅰ号饲料配方的增长率最高。

不同饥饿时段对黑鲷(Acanthopagrus schlegeli)ghrelin基因表达的影响

设计了黑鲷ghrelin基因的特异性引物,提取胃组织总RNA并扩增出目的片段,将PCR产物克隆到pGEM-T Easy载体,经质粒PCR扩增、酶切和测序鉴定重组质粒,构建标准曲线等,成功建立了ghrelin基因荧光实时定量PCR检测方法,以准确分析ghrelin基因在黑鲷摄食调节中的作用。运用建立的荧光实时定量PCR方法检测了不同饥饿时段(2天、7天)黑鲷胃、肠、下丘脑组织中ghrelin mRNA的表达变化。结果表明,饥饿2天(短期饥饿),黑鲷胃、肠组织中ghrelin mRNA表达显著上升(P<0.05),下丘脑ghrelin mRNA表达无显著变化(P>0.05);饥饿7天(长期饥饿),黑鲷胃、肠组织ghrelin mRNA表达比饥饿2天显著下降,但仍显著高于对照组,下丘脑ghrelin mRNA表达逐渐升高(P<0.05);在同一饥饿时间内不同组织ghrelin mRNA表达存在显著差异(P<0.05)。黑鲷不同组织ghrelin基因的表达随不同饥饿时段呈现出不同的变化趋势,推测ghrelin基因参与了黑鲷摄食调节的生物学过程。

光照、温度对黑鲷(♀)×真鲷(♂)杂交子代受精卵孵化效果的影响

为了研究不同光照强度、温度对黑鲷(Acantho pagrusschlegelii)(♀)×真鲷(Pagrosomus major)(♂)杂交F1代受精卵孵化效果及仔鱼存活的影响,作者采用试验生态学的方法比较不同温度(16、18、20、22、24、26℃)下杂交鲷受精卵的孵化率、畸形率、孵化时间、7日龄仔鱼的存活率;比较不同光照强度下(10、100、300、800、1500、4 000、10 000 lx)受精卵孵化率、畸形率、孵化时间;比较不同光照强度下(200、1 000、2 000、5 000、10 000、15 000、20 000 lx)7日龄仔鱼的存活率。结果表明:在盐度为22条件下,受精卵最高孵化率(34.00%)和最低畸形率(16.65%)的孵化温度为20℃;在16～26℃范围内,温度与孵化时间呈负相关,与7日龄仔鱼存活率也呈负相关。不同的光照强度对受精卵孵化率和孵化时间的影响不显著,孵化率为65.88%～71.88%;但大于800lx的光照会令畸形率上升(大于15.21%);另外,5000～10000lx的光照强度更适宜仔鱼生存,7日龄仔鱼存活率达到38%～40.75%。黑鲷(♀)×真鲷(♂)杂交子代最佳孵化温度为20℃,最适光照强度为5 000～10 000 lx。

腹腔注射LHRH-A对黑鲷生长激素及其受体的影响

以海水硬骨鱼类黑鲷为研究对象,腹腔注射溶于生理盐水的促性腺激素,释放激素(gonadotropin releasinghormone,GnRH)的类似物(analogueofluteinizinghormone releasinghormone,LHRH A),对照组注射生理盐水.24h后注射LHRH A组黑鲷血清生长激素(growthhormone,GH)水平显著高于对照组(p<0 05),于36h又恢复到对照组水平.注射LHRH A组肝脏生长激素受体(growthhormonereceptor,GHR)及GHRmR NA均与对照组无显著差异.结果表明,腹腔注射LHRH A刺激了处于性腺成熟期黑鲷GH的分泌,但对黑鲷肝脏GHR及其基因表达无明显影响.

盐度变化对黑鲷生长激素及其受体的影响

将海水鱼类黑鲷Sparusmacrocephalus从盐度为26.6的海水直接转入淡水,考察渗透压的急剧降低对黑鲷的生长激素(growthhormone,GH)及其受体(growthhormonereceptor,GHR)等生理指标的影响。研究发现:(1)黑鲷从海水直接转入淡水后48h有33%的鱼死亡,对照组无死亡现象;(2)黑鲷在转入淡水48h内其血清生长激素(GH)含量、肝脏及鳃中GHR及GHRmRNA含量与对照组均无显著差异;(3)黑鲷在转入淡水48h后其肾脏中GHR含量较对照组显著升高(p<0.05),肾脏中GHRmRNA含量在24h及48h显著高于对照组(p<0.05)。结果表明,从GH含量看,黑鲷从海水环境到淡水低渗环境与鲑鳟鱼类从淡水到海水环境的适应性调节机制有差异,而黑鲷肾脏中GHR的含量变化可能参与黑鲷对外界环境渗透压的这种急剧降低的适应性调节。