Abstract:In 2010—2011,active Antarctic krills(Euphausia superba)which survived and were collected immediately in the capture by a pelagic trawl with the factory trawler “Anxinghai” near South Orkney Island and were transferred to a test tank and their behaviors were observed.45 Antarctic krills were observed during the experiment,and the body length were 37-55 mm,the light intensity of water surface in test tank was kept at 220 lx, and the temperature of the water in test tank was constant at 0 ℃.The whole experiment lasted for 13 days.There are three results obtained from the experiment:(1) Body color of Antarctic krill changes rapidly after being put into test tank under lighting;(2) In static condition,Antarctic krill almost keeps in the same position in corners.When they moved,they could swim from one corner to a neighbor corner along the wall of the tank,and a few times to swim with a higher speed across the center of the test tank;In hydrodynamic conditions,they can swim against the current and aggregate to a schooling at a velocity about 0.5 m/s,schooling vanished while current is greater than 1 m/s;(3) Antarctic krill molted during the experiments,and the average body length increased about 5-8 mm.

Abstract:Genetic variation of four strains of Meretrix meretrix, thin checkered(TC),black spot(BS),dark fringe(DF)and red shell(RS)was studied.Thirty randomly selected individuals from each strain and nine polymorphic microsatellite loci were used for genetic analysis.A total of 105 alleles were identified, the most alleles were 21(WG07)and the least locus were 7(WG11).The distribution of the alleles for the same loci was different in different strains and specific allele types were detected in each strains.All the microsatellites were highly polymorphic,and various genetic variability measures,including observed heterozygosity(0.486 to 0.867), expected heterozygosity(0.110 to 1.000), and polymorphism information content(0.433 to 0.834),Chi-square tests showed that most of the cases in four strains deviated from Hardy-Weinberg equilibrium.Pairwise F_ST ranged from 0.005 to 0.269.Genetic distances among strains ranged from 0.052 0 to 0.098 0.The results of cluster analysis indicated that TC strain had higher genetic difference than other strains,then was BS strain,and the genetic variation between DF and RS strains was relatively lower.

Abstract:In this study,the sorbent was prepared from fish scale of grass carp and the absorption capability of this sorbent to different chemical dyes was determined.At the same time,the best absorption conditions and the absorption mechanism of this sorbent were studied by use of kinetic and thermodynamic analysis and FTIR assay.The results show that the adsorbent from fish scales has good absorption capacity for the dyes which have sulfonic acid group and the order of adsorbent capabilities to different dyes is:Congo red＞carmine＞brilliant blue＞sunset yellow＞methylene blue.While the temperature was 25 ℃,the absorbent dosages was 0.2 g/L,the potential of hydrogen was 7,the concentration of Congo red was 14 μg/mL,and the effect of fish scales sorbent on Congo red was the best.The quasi secondary dynamic model could reflect the isothermal absorption dynamics of different dosage of fish scales sorbent.The results of kinetic and thermodynamic analysis showed that the endothermic process of this adsorbent was spontaneous and irreversible.The infrared analysis showed that the functional groups of fish scales on Congo red absorption were composed of amino,carboxyl,phosphate groups and so on,which belonged to protein and hydroxyapatite of fish scales.

Abstract:The Pacific oyster Crossostrea gigas and the Portuguese oyster C. angulata are two subspecies and are also the most important two cultured oysters in China, which have been separately cultured in North and South China. In order to improve production by exploring heterosis, two hybrid groups of NS (N♂?S♀) and SN (S♂?N♀) and two purebred groups of NN (N♂?N♀)and SS (S♂?S♀) were established using a diallel cross design with the parents of the Pacific oyster from Qingdao of Shandong (N) and the Portuguese oyster from Shantou of Guangdong (S). The present results showed that hybridization between the two close related species was successful. Two production traits of growth rate and survival rate for hybrids were both improved, and significant heterosis for them was obtained. The hybrids grew faster than the purebreds, and heterosis for growth rate is 37.44℅ at larvae stage and 42.47℅ at spat stage, respectively. The hybrids also survived more that the purebreds, and heterosis for survival rate is 76.80% and 107.70% for larvae on day 8 and 14, and 17.30%, 15.62% and 9.08%, respectively. Our study showed that some problems such as harder breeding seeds, lower survival rate, slower growth, and smaller size influencing oyster production could be solved by cross breeding between the two subspecies.

Abstract:Calcium is essential for living organisms. Even with an apparently sufficient intake of dietary calcium, there is some concern that inadequate calcium is absorbed by the small intestine, due to precipitation of insoluble calcium salts in the neutral to slightly basic intestinal lumen. Some studies revealed that peptides have the capacity to chelate Ca and to prevent the precipitation of insoluble calcium salts, thereby increasing the amount of soluble Ca availability for absorption across the mucosa. However, the mechanism and degree of calcium ion binding are still unclear. In this paper, the combinations between collagen polypeptide (from the enzymatic hydrolysate of channel catfish bone powder) and calcium ion were studied by measuring chelate rate. On the basis of results of single-factor experiments, the Box-Behnken central composite design and response surface method were adopted to obtain the optimum conditions for chelate. The optimal chelate conditions were determined as: chelate temperature 60℃, chelate pH 5.4, chelate time 1.5 h and ratio of collagen polypeptide to calcium 2:1 (w/w). Under the optimized conditions, the chelate rate of Ca-collagen polypeptide could achieve to 82.53％. The formation of Ca-collagen polypeptide chelate was confirmed by the UV-VIS and FT-IR spectra. The characterization of amino acid composition of the chelate was similar to typical collagen-like protein. This research provides a practical guideline and theoretical basis for fully excavating fish bone protein resources and developing the deep processed products.

Abstract:Blue mackerel scad,Decapterus maruadsi Temminck et Schlegel,is an important pelagic species which is distributed in the coastal areas of China.In the present paper,a total of 444 specimens of blue mackerel scad at fork length(FL)of 52-276 mm were sampled from seasonal lightpurse seine surveys in the East China Sea from May 2008 to February 2009.By analyzing the stomach contents of Decapterus maruadsi,more information was provided on the East China Sea fish feeding ecology.The results showed that more than 80 prey species were ingested by blue mackerel scad,while planktonic crustaceans and smallscale marine fish constituted the dominant prey groups.Among the crustaceans,planktonic larvae,euphausiacea and copepoda made an important contribution to the diet.At the species level,as indicated by the percentage index of relative importance,Benthosema pterotum accounting for 40.44% was the most dominant prey,followed by theSquillidaealima larva accounting for 14.24%,Euphausia pacifica accounting for 11.26%.The percentage of empty stomachs and mean stomach fullness index,which were analyzed by applying the chi-square test and Kruskal-Wallis test,varied significantly among different seasons and size classes.It indicated that the feeding intensity was the highest in spring and lower in winter.Meanwhile,the feeding intensity was the highest in size classes of 50-99 mm and 200-299 mm while the lowest in other size classes.The major diet composition was significantly different among different seasons and size classes.The B.pterotum and Squillidae alima larva were the dominant prey in spring,whereas the planktonic crustacean larvae in summer,B.pterotum and Euphausia pacifica in autumn,Oncaea venusta and mysidacea in winter.Cluster analysis employing Bray-Curtis similarity index revealed there was an abrupt change in diet composition at about 200 mm FL.The planktonic crustaceans were the dominant prey groups of fish smaller than 200 mm FL,whereas smallsize marine fish were the dominant prey for fish greater than 200 mm FL.It indicated that the percentage of nekton significantly increased with the increase of fish size.Compared with the previous studies,the diet composition of D.maruadsi varied significantly,the proportion of B.pterotum decreased markedly.In addition,the average trophic level of D.maruadsi in the East China Sea was 3.55,which was carnivorous fish feeding on plankton and necton.

Abstract:The fisheries biology characters of Johnius belangerii,including size composition,relation of body length and weight,sex ratio,reproduction habits and diet,were analyzed based on the data collected from January 2009 to February 2010 off Ma’an Archipelago.Results showed that the body length range of J.belangerii was 30-264 mm,and the dominant body length groups were 80-100 mm and 130-180 mm.Juveniles and males showed a negatively allometric growth,while females showed a positively allometric growth.Sex ratio(females:males)was 1.68:1 and it varied with months and body length obviously except August and September and length groups 110-150 mm and 160-180 mm.The reproductive season was from June to September.The estimated ML₅₀ for females and males were 124.8 mm and 136.4 mm,respectively.The diet compositions changed along with month and body length.Juveniles mainly preyed on amphipoda and the adults mainly fed on fish and shrimps before reproduction and fed on amphipoda during reproductive period.The range of body length and length of dominant body length groups ofJ. belangerii,off Ma’an Archipelago were greater than other sea areas.Measures relating to reproductive stock and juveniles of J. belangerii protection should be taken in order to achieve continuous use of this species’ resources.

Abstract:Based on the fishery resources monitoring data collected in Guanjingyang sea in Fujian from 2010 to 2011,the present study analyzed the biological characteristics(n=2 098)of large yellow croaker(Larimichthys crocea),including body length and weight,growth and death,sex ratio,and sexual maturity.von Bertalanffy growth equation and parameters of mortality rate have been used to analyze the current resources status of large yellow croaker in Guanjingyang sea,meanwhile,biological characteristics(inflexion age and critical age,etc.)of fishery have been discussed.The results indicate that the average body length is 132.6 mm,with the group of predominant body length 110-150 mm,accounting for 55.96%;the average body weight is 45.1 g,with the group of dominant weight 10-50 g,accounting for 61.77%.The juvenile large yellow croaker and recruit population have been the main catch targets.The relationship between length and weight was expressed as:W=2.001?10^-5L^3.006.The growth parameters of von Bertalanffy formula estimated by ELEFAN were L_∞=385.4 mm,k=0.43 and t₀=-0.32a,respectively,and flexion age is 2.2 years.Compared with the data obtained about large yellow croaker in Fujian,value of L_∞ has declined from 555.4 to the current 385.4,flexion age from 2.97 to 2.2,all these trends show that the group has been in serious status characterized with miniaturization and lower age.In addition,the growth coefficient shows an apparent increase from 0.36 to 0.43,which indicates a speedup growth in large yellow croaker.Total death coefficient(Z),natural death coefficient(M)and the coefficient of fishing death(F)are 3.12,0.45 and 2.67 respectively;the exploitation rate in recent years was 0.856.The increasing trend of M value may be related to the deterioration of marine environment in coastal areas of Fujian;and,due to the high-intensity catch of large yellow croaker,fishing death of such species is increasing sharply,from 0.84 to 2.67,which indicates that the stock of large yellow croaker has been over-exploited.Under the current resources status in Guanjingyang sea,great effort should be made to reduce fishing mortality and protect its environment so as to protect large yellow croaker.And due to the miniaturization and low age of large yellow croaker resources,controlling the catchable age(t₀)is suggested to be the main management.

Abstract:The embryonic development pattern of walleye pollock and the morphological characteristics of fertilized eggs were observed and recorded from October to December in 2008.The egg diameters in six stages were measured and the egg envelopes of seven stages were also studied with scanning electron microscopy.The egg of walleye pollock was pelagic,without oil globules.The diameter was 1.45-1.58 mm,the incubated temperature was(6.3?1.24) ℃ and the salinity was 34 psu.The microscopic observation showed the fertilization tube opened with (4.33?0.31) μm pore diameter;the pore canals of the egg envelope were inconspicuous;the interval of micropyle and density of the pore canals of the egg envelope were(1.46?0.31) μm and 21.1-30.6/100 μm² respectively.The micropyle with the micropyle canal was completely plugged with material at the 2-cell stage,and the fertilization pore diameter was(5.26?0.29) μm.The egg envelope contained less ruffles and the pore canals of the egg envelope became more prominent and the interval of micropyle was(2.04?0.35) μm.The density of the pore canals of the egg envelope was 14.7-20.3/100 μm².After the closing phase of blastopore,the fertilization pore of egg presented the open state;few secretions were adhered to its periphery region.The diameter of the fertilization pore,interval of the pore canals and density of the pore canals of the egg envelope were(4.48?0.15) μm;(1.70?0.23) μm;and 23.59-27.53/100 μm²,respectively.Approaching the incubation period,the egg envelope had a rough surface,on which the pore canals were inconspicuous with a (2.56?0.22) μm interval and the density was 12.38-15.97/100 μm².The diameter of egg,the fertilization pore,as well as the dynamic change of structure of egg envelope,were closely related to the embryonic development of Alaska pollock.The above indexes had great importance in improving the fertility rate of egg,facilitating the normal development and spread of egg on seabed,and preventing both polyspermy and bacterial infection during the egg development process.

Abstract:The marine grouper species are considered high value food fish in Southeast Asia.Aimed to get some new types of grouper,we have successfully cross-bred three species of grouper.The hybrid grouper was produced by fertilising the eggs of the orange-spotted grouper(Epinephelus coioides),tiger grouper(Epinephelus lanceolatus)with the sperm of the giant grouper(E.lanceolatus)through thein vitro fertilisation technique.The hybrids combine morphological features of the two parent species.And they are healthy and growing well in sea cages and the finding will be good news for the aquaculture industry.The genetic diversity among orangespotted grouper,tiger grouper,giant grouper and their hybrid F₁ generation population(Qinglong grouper and Hulong grouper)were tested by 6 microsatellite loci.The gene frequency,effective number of alleles(A_e),observed heterozygosity(H_o),polymorphism information contents(_PIC),genetic similarity and Nei’s genetic distances(D)were studied.The results showed that,the E.fuscoguttatusshowed the most alleles(6.849 3),while theE.lanceolatusshowed the least(2.608 6).Rich polymorphisis was observed by the six primers,and thePIC values in the five populations were 0.666 7,0.751 3,0.441 9,0.664 0,0.542 6,respectively.And the F₁ generations showed the highest observed heterozygosity(H_o)of 0.940 0,while theE.lanceolatus showed the lowest value of 0.508 3.The results of genetic distances and genetic similarity showed that both F₁ generations had a close relationship with the male parent E.lanceolatus.The alleles of F₁ generations were mostly generated from both of their parents,which mean that the genetic materials were inherited from parents.And the higher genetic diversity that existed in the two hybrids indicated potential heterosis.

Abstract:Although females grow 4-6 times faster and reach larger adult sizes than males in half-smooth tongue-sole,Cynoglossus semilaevis, male ratio is higher than female study culture conditions.Thus,it is necessary for us to make a detailed understanding of gonadal development,which provides a theoretical basis for sex control.What’s more,water temperature is considered a very important modulator of reproductive activity in fish.Therefore,the principal purpose of the present work is to analyze the effects of different temperatures(19,21,23,25 and 27 ℃)on gonadal development in the half-smooth tongue-sole,which were reared for 67 days from 39 to 106 days post fertilization(pfd).And the temporal dynamics of germ cell growth and gonad development were examined during the experiment using light microscopy method.We found that the histological differentiation occurred firstly on pfd46 in the half-smooth tongue-sole reared at 19 ℃,as the gonad with the increasing primordial germ cells(PGCs)will develop into ovary.And the gonad without cavity will develop into testis in fish held at 19 ℃ on pfd82.At the same time,compared with fish kept at other temperatures,half-smooth tongue-soles maintained at 27 ℃ demonstrated increased oogonium proliferation in females and the spermatocyst size in males.And the ovaries of the fish reared at 27 ℃ were in stage Ⅱ on pfd129.Higher water temperatures triggered rapid germ cell differentiation and seminal vesicle growth,and relatively,lower water temperatures delayed,hence,not until pfd142,the ovaries of juvenile feeding at 23 ℃ and 25 ℃ were in stageⅡ.In addition,under higher temperature treatment,there were more oocytes in the ovarian lamella;in males,late-stage testis germ cells were predominated at this time,Especially in the juveniles rearing at 25 ℃,spermatozoa were distributed to almost all seminal lobules,even seminal vesicles and sperm ducts were filled with high density spermatozoa.All of these results suggest that higher water temperature favors gonadal development.

Abstract:The full-length cDNA of insulin-like growth factor binding protein 1 gene(IGFBP-1) was obtained from the liver of Japanese flounder(Paralichthys olivaceus)using RACE method. The complete cDNA of P.olivaceus IGFBP-1 is 1 070 bp and its ORF includes 729 bp encoding 242 amino acid residues.The IGFBP-1 was highly homologous with IGFBP-1 gene in fish through phylogency analysis. The nucleotide sequence of IGFBP-1 from P.olivaceusshared 95% homology with that of Scophthalmus maximu,and the deduced amino acid analysis showed that the sequence similarities betweenP.olivaceusand S.maximu,Seriola quinqueradiata,Perca flavescens,Salvelinus alpines,Cyprinus carpio andDanio rerio,are 89%,89%,84%,79%,67% and 67%,respectively. Semi-quantitative RT-PCR results demonstrated that IGFBP-1 mRNA was detected in unfertilized egg,fertilized egg,embryonic and larval development,and various adult tissues.Moreover,real-time quantitative RT-PCR results showed that IGFBP-1 gene had the highest expression in adult liver and was expressed in a stage-specific manner during embryonic and larval development.

Abstract:A series of characteristic cytological events during fertilization and early embryonic development in Apostichopus japonicus were studied by the fluorescence microscope with HOECHST 33258 stained.The results indicated that unfertilized mature eggs of A. japonicus were globular and remained at the metaphase of meiosis Ⅰ.At water temperature of 22-23 ℃ and salinity 29,sperms quickly attached to the surface of the egg after mixing of sperms and eggs.At 12 min after insemination,the first meiosis is finished,with release of the first polar body.Most of fertilized eggs released the second polar bodies at 20 min after insemination.About 35 min,the male and the female pronuclei associated with each other after their chromosomes formed respectively in the center of egg.The first and second cleavages finished at 80 min and 100 min respectively in fast developing fertilized eggs.Polyspermy phenomena were observed in the fertilization process in A. japonicus.

Abstract:To examine the effect of different two-carp ratios between silver carp Hypophthalmichthys molitrix and bighead carp Aristichthys nobilis cocultured in the mussel pond on growth of freshwater pearl mussel Hyriopsis cumingii and water quality,an enclosure experiment was carried out in Tangxi of Zhejiang Province from April 23 to September 21,2008.Two-carp ratio was set at six levels:0/0(control group),100/0,70/30,50/50,30/70 and 0/100.Shell length,shell width and wet weight of pearl mussels were measured at the beginning and the end of the experiment,respectively; and the water quality parameters including NO₃-N,NO₂-N,NH₃-N,TN,TP,PO₄-P,COD were determined twice a month during the experiment.The results showed that the relative growth rate of mussel shell length in level 100/0(silver carp vs.bighead carp ratio)were significantly lower than that of levels 0/0,50/50 and 0/100(P<0.05),and no significant differences were found among survival rate,growth rate of shell width and wet weight of mussels at various polyculturing two-carp ratio levels(P>0.05).Besides,enclosures at level of 30/70 had better water quality in which TP was significantly lower than 100/0(P<0.05),COD was significantly lower than 100/0 and 70/30(P<0.05),NH₃-N was significantly lower than 100/0(P<0.05)and PO₄-P was significantly lower than 70/30(P<0.05).So the ratio of 30/70 of silver carp vs.the bighead carp was the best polyculture ratio for mussel culture in terms of the growth and water quality parameters.

Abstract:Wnt1 inducible signaling pathway proteins(WISP()constitute the CCN family with CYR61,CTGF and NOV.We used BLAST program at the NCBI to identify near matches in the common carp( Cyprinus carpio)genome database to each zebrafish( Danio rerio) WISP . WISP 1a, WISP 1b, WISP 2 and WISP 3 were identified respectively.ORF of the four isforms of WISP were cloned and sequenced in common carp. WISP 1a was 1 089 bp encoding polypeptides of 362 amino acids with a calculated Mw of 41.2 ku and P I of 8.66. WISP 1b was 1 077 bp encoding a polypeptide of 358 amino acids with a calculated Mw of 41.0 ku and PI of 8.42. WISP 2 was 1 038 bp encoding polypeptides of 345 amino acids with a calculated Mw of 38.4 ku and PI of 8.22. WISP 3 was 1 026 bp encoding polypeptides of 341 amino acids with a calculated Mw of 37.9 ku and PI of 9.10.They all have 5 exons and 4 introns.Phylogenetic relationship analysis indicated that WISP 1, WISP 2 and WISP 3 were highly homologous and were clustered to their corresponding subgroup respectively. WISP 1a, WISP 1b and WISP 2 all contained 4 conservative domains and WISP 3 lost the second domain in common carp.RT-PCR analysis revealed WISP 1a to be expressed in most common carp tissues,with the principal expression in skin and weakest expression in blood cells. WISP 1b was predominantly expressed in testicle,brain,skin and ovary. WISP 2 was highly observed in blood cells and gill. WISP 3 was most strongly expressed in blood cells and also expressed in brain,liver,spleen,head kidney and not detected in other tissues.Quantitative real-time PCR were used to analyse the expression of WISP in common carp development,and the result indicated that WISP transcriptions are expressed highly at the initial stage except WISP 3 and all lowest at 36 hpf and then increased before 6th d.

Abstract:In order to improve the quality of Litopenaeus vannamei seedlings and explore the application of mass selection and crossbreeding methods in large-scale production of artificial breeding,a comparative study on inbred and hybrid offsprings within stock A was carried out.Stock A was introduced from America in 2008 and was then artificially selected for two generations.Stock B was selected from Guangdong cultured population in 2010.The inbred line AA(A♀?A♂)and reciprocal cross lines AB(A♀?B♂)and BA(B♀?A♂)between these two stocks were established.Then a comparative study on growth,low-salinity and low-temperature resistance at larval stages was conducted among these three lines.The results showed that the offsprings for AB showed the best resistance capacity of low-temperature and lowsalinity among three lines.Under the low temperature of(13.0?0.9) ℃ and the low-salinity of 4.7 conditions,the survival rates for AB line was 27.5% and 64.6% higher than that of the inbred line AA,respectively.The growth rate for body weight at the grow-out stage were (253?55) mg/d for AB line,(208?52) mg/d for BA line and (219?36) mg/d for AA line.The growth rate for AB line was 21.6% and 15.5% faster than that of BA and AA lines.The results indicated that heterosis of Litopenaeus vannamei was closely related with mass selection for broodstock.

Abstract:By the methods of experimental ecology,a 5-3 factorial experiment was conducted to determine the effects of salinity and dietary protein levels on molt and growth of Litopenaeus vannamei.The experiment lasted 30 days. L.vannamei at an initial average weight of (2.01?0.02) g were divided into triplicate groups and were observed at salinities of 6,12,18,24,30 and protein levels of 30%,36%,42%.The results showed that the relative weight gain of molting decreased with increasing salinity,being the highest at salinity of 6.The relative weight gain of molting was affected significantly by different salinities and dietary protein levels,and the interactions of them(P＜0.05).The specific growth rate increased with increasing salinity,it was affected significantly by the different salinity and dietary protein levels(P＜0.05),but it was not affected significantly by the interactions of them.The molting frequency increased with increasing salinity low salinity levels(P＜0.05),being the highest at salinity of 18,then it decreased with further increasing salinity.At the different dietary protein levels,the higher molting frequency was obtained in experimental group with feed to the medium dietary protein levels diet(36%).The molting frequency was affected significantly by the different salinity and dietary protein levels(P＜0.05),it was not affected significantly by the interactions of them.The intermolt period was first prolonged,then shortened with the increase of salinity.The intermolt period was affected significantly by the difference salinties(P<0.05),but not affected significantly by the dietary protein levels and the interaction of them.

Abstract:The South China Sea(SCS)surrounded by the first island chain is a semienclosed sea linking the Indian Ocean and the Pacific Ocean.The population genetic features of the two most important economic species,yellowfin tuna(YFT,Thunnus albacares,17 adults and 44 juveniles)and big eye tuna(BET,T.obesus,22 adults and 4 juveniles)in SCS(11-12?N,15?N;110-112?E),have been analyzed based on the partial mitochondrial D-loop sequences.Our data supported the following conclusions:(1) both species were high nucleotide variation with very high haplotype diversities(H_d＞99%),while the evidence from fixation indexes,and cluster trees showed the population diversity of BET was higher than those of YFT;(2) For BET and YFT,the strongest gene flow between populations in SCS and the Indian Ocean were 51.638 and 261.280 10,then the Pacific by 10.868 8 and -50.801 81,respectively;(3) both species obey the sudden expansion model.Contrasted with the unimodal of YFT,the mismatch distribution of BET,as well as the SCS population,were bimodal.Moreover,the spanning time of SCS population of BET was later inferred from the T_au(=7.902)with biggest spanning scale(θ₁/θ₀=99 999/14.752).The results should be basic information for fisheries management,fishing quotas determination as well for aquaculture of tuna.