Abstract:In order to deeply understand the immune function of Vc,we fed different levels(0%,0.5%,1%,2%)of Vc to study the influence on the Chinese shrimp.We detected survival rate and activity of iNOS,CAT and LZM at the different experiment times of Chinese shrimp.Using realtime fluorescent quantitative RT-PCR approach,expression TLRs and NF-κB genes were examined in serum and gills of the Chinese shrimp.Results showed that:(1) VC can raise the survival rate and the activity of iNOS,CAT and LZM.The 1% groups show the best immune activating effects among groups,with survival rate at 90.3%,significantly higher(P<0.05)than that of other groups.(2) Vc has regulatory activity on mRNA expression of TLR and NF-κB.There are significant differences(P<0.05)on TLR expression in the serum and gill of 1% group compared to the control.NF-κB mRNA expression in serum of 1% group is higher than that in other groups,but that in 2% group has the highest levels in early six days,and then declines even lower than the control.NF-κB mRNA expression in gill of 2% group is higher than control.Overall,these results demonstrate that Vc can effectively improve the survival rate and the activity of three non-specific immunity enzymes of the Chinese shrimp and regulate the expression level of TLRs and NF-κB.

Abstract:A rapid multiplex-PCR method was established in order to detect four common foodborne pathogenic bacteria including Salmonella spp., Staphylococcus aureus,Vibrio parahaemolyticus and Shigella spp.in aquatic products.Four pairs of oligonucleotide primers were designed for multiplex-PCR amplification according to gene coding invasion protein A of Salmonella spp.,gene coding heat stable nuclease of Staphylococcus aureus,gene toxin regulatory protein of V.parahaemolyticus and invasion plasmid antigen H gene of Shigella spp.The amplified fragment sizes of these four bacteria were 549 bp,426 bp,348 bp,243 bp,respectively.Then four main factors of multiplex-PCR system were optimized,also the specificity and sensitivity of this method was detected.The final 50 μL reaction mixture contained 1.2 μL nuc primers,1.2 μL ipaH primers,1.6 μL toxR primers,1.6 μL invA primers,0.6 μL Taq enzyme,3.5 μL Mg²⁺,4 μL dNTP and 1 μL DNA template for each bacterium.The sensitivity was as low as 10 CFU/mL for Salmonella spp.,Vibiro parahaemolyticus and 10² CFU/mL for Shigella spp.,S.aureus.A general enrichment broth was optimized to allow simultaneous growth of these four bacteria in samples.The multiplexPCR method was used to analyze 35 aquatic product samples compared with national standard methods,the coincidence rate of two methods was greater than 95% and there was no significant difference between these two methods(P＞0.05).Therefore,it was suggested that the method developed in this study had high sensitivity and specificity,and could be applied for the rapid detection and molecular epidemiology survey of foodborne pathogenic bacteria in aquatic products.

Abstract:The distribution of 5-HT in main cells of both ovary and hepatopancreas at different ovary stages of Neomysis japonica was observed and compared by using immunohistochemical method.These cells included follicule cell,oogonium,endogenous vitellogenic oocyte,exogenous vitellogenic oocyte,mature oocyte,embryonic cells,blister like cells,resorptive cells,fibrillar cells.The results showed that changes on the distribution of positive 5HT cells were observed with ovary development.All the follicule cells are stained positively at each ovary stage.As for the oocyte,both the cytoplasm and nucleus are stained positively during the early developmental stages,including Stage Ⅰ,Ⅱ,and Ⅲ.But the positive intensity presents a negative trend with ovary development.The oocytes are stained negatively at Stage Ⅳ whereas they were found weak positive in Stage Ⅴ.In contrast,the hepatopancreas cells are stained positively during each stage.Moreover,there are no significant differences of positive 5HT in different types of hepotapancreas cells during the ovary development.In addition,the 5HT positive intensities of oocyte were consistent with hepatopancreas cytoplasm throughout all ovary developmental stages(except Stage Ⅳ).

Abstract:The Ca²⁺metabolism is one of vital factors relative to growth of shell and pearl in freshwater mussel.In order to probe the Ca²⁺absorption and transportation in freshwater shellfish,Ca²⁺ concentration of cells(under resting state)from different tissues and effect of Ca²⁺ concentration of culture medium on Ca²⁺ deposits within the cells from outer mantle were researched by technology of laser scanning confocal microscopy in Hyriopsis cumingii.The total of healthy 10 H.cumingii with pearl and without pearl were selected,and then the cells from their mantle,gill,foot and epidermis of visceral mass were isolated.After short-term culture,the cells were incubated using DMEM with different Ca²⁺ concentration(0,0.5,1.25,3 mmo1/L)and fluorescence probe of Fluo3/AM for 1 h.The green fluorescence intensity was acquired to analyze the Ca²⁺ levels in these cells.The results showed that there were significant differences among intracellular Ca²⁺ fluorescent itensity of 5 kinds of cells(P<0.05):intracellular calcium ions fluorescent intensity of the outer mantle cells was highest(P<0.05),while intracellular Ca²⁺ fluorescent intensity of visceral mass epidermal cells was the lowest(^P<0.05).The intracellular Ca²⁺ fluorescence intensity of mantle cells in mussel with pearl mussel had increasing trends compared to that in mussels without pearl under the same Ca²⁺ level,and the difference was significant between the two groups of inner mantle with 1.25 mmol/L Ca²⁺level(P<0.05).Influence of different Ca²⁺ incubation levels on intracellular Ca²⁺fluorescence intensity were significant(P<0.05).With increasing Ca²⁺ concentration in incubating medium,intracellular Ca²⁺ fluorescence intensity of mantle cells was significantly enhanced(P<0.05).The present research indicated that mantle was main tissue on absorbing Ca²⁺ from external water;pearl cultivation strengthened calcium deposition in body of H.cumingii;calciumion concentration of 1.25-3 mmol/L in water was beneficial to Ca²⁺ deposition in mussel.Our research provided theory basis for pearl cultivation in fresh-water mussels.

Abstract:China is the main country of aquatic products production in the world.The output of aquatic products has been ranking first in the world for twentyone years.However,the utilization percent is low,and it causes serious resource waste and pollution.The improvement of fishery resources utilization efficiency is important to reducing environmental pollution,improving the economic benefits of aquatic product processing plants,increasing the consumption level of the people and realizing high efficient and low carbon in the aquatic product processing industry.The head and shell portion of shrimp is removed during processing and it yields large amount of wastes.Autolysis technology effectively recovered the protein and other nutrient components,and a low alkali method was carried out to recover the chitin efficiently.The processing was low pollution and the products had high added value.Thus it achieved a high efficient and low carbon utilization of shrimp.The low carbon and high efficient utilization technology of shrimp has been industrialized in several enterprises.The economic benefits were notable.Good demonstration effects can be expected for the processing of other aquatic products.Based on the above content,the paper prospects the trends of the low carbon processing technology of aquatic products.

Abstract:In order to study the capability of utilizing carbohydrate in the diet and the effects of different carbohydrate diets on allogynogenetic crucian carp,artificial purified feed with normal(including 35% carbohydrate)and high(including 50% carbohydrate)level carbohydrate were applied.168 individuals of allogynogenetic crucian carp［(35.60±1.11) g］ were divided into the two carbohydrate level groups,and each group has three replicates which were cultured in aquarium with automatic temperature control culturing system with recycling water for 10 weeks.After that,indicators of fish growth,plasma biochemical indices and immune indicators were measured.The results showed the specific growth rate,weight gain rate were significantly lower than normal carbohydrate group(35%CHO),but no significant difference on feeding rate,feed conversion rates,muscle composition,hepatosomatic indices,gonad indices and fullness coefficient.The total plasma protein,plasma triglycerides,total cholesterol,blood glucose and hepatic glycogen did not significantly change(P>0.05).The hepatic MDA content of 50%CHO group was significantly(P<0.05)higher,while the AST was significantly(P<0.05)lower.The hepatic SOD,T-AOC,ALT,and AKP had no significant(P>0.05)differences between 35%CHO group and 50%CHO group.The hepatic ultrastructure in allogynogenetic crucian carp have been investigated using transmission electron microscopy.The result shows high carbohydrate dietary induced sedimentation of glucose and fat in hepatic cell,and structure damages are observed as well.Overall,50% carbohydrate dietary has impacts on growth,hepatic immunity function and induces structure damages,although allogynogenetic crucian carp has greater tolerance for it.

Abstract:To examine the change traits of chyme mass and fit to the gastric evacuation data in juvenile southern catfish(Silurus meridionalis),forty eight experimental fish［(58.45±1.66) g,(19.4±0.2) cm］were fed individually with a loach meal［(3.33±0.09) g］equivalent to 6%(5.8%±0.2%)of the catfish’s body mass,and removed from the various intervals(0,2,4,8,16,24,36,48 h)after feeding at 25 ℃.The wet and dry mass of the chyme were determined and the applicability of three mathematical models was compared by the good of fitness fitted to gastric evacuation data in juvenile southern catfish.The results of present study showed that:the wet and dry mass of remaining food in stomach as well as percentage of food residual decreased profoundly as postprandial time increased;Though three mathematical models all fitted well the gastric evacuation data,there still were several significant differences among these regression results.As mentioned above,it suggested that the best mathematical model fitted to gastric evacuation data in juvenile southern catfish was the squareroot model and its regression equations for wet mass and dry mass of the chyme mass were Y^0.5=1.889-0.051×t(R²=0.87,P<0.001)and Y^0.5=0.870-0.024×t(R²=0.86,P<0.001),respectively;The gastric evacuation rate of S.meridionalis was among the range of 0.051 g/h,and the 99% of gastric evacuation time was among the range of 36.7 h which was similar to the actual measurement values(36 h)in the present study;The juvenile southern catfish and Chinese catfish possess the similar gastric evacuation characters and the optimum mathematical model was the squareroot model.

Abstract:Based on the bottom trawl surveys in four seasons from 2006 to 2007 inside bottomtrawl fishing forbidden zone line of Jiangsu sea area and the near zone,we explored the temporal and spatial distributions of Larimichthys polyactis Bleeker resources in this target area,as well as their mechanism.The results showed that:(1) spawning and feeding groups in offshore areas of Jiangsu Province were composed of South Yellow Sea population mainly,with East China Sea population and smaller YellowBohai Sea population;(2) the biomass of Larimichthys polyactis Bleeker was higher in spring and summer,with the highest in summer,and decreased following the order of spring,autumn and winter;(3) the distribution areas extended to north gradually with seasons,and the move tendency was obvious from autumn to winter;(4) in the radiating sand ridge and the surrounding regions,total average biomass of Larimichthys polyactis Bleeker in a year was much higher than that in the north-central area of the offshore areas of Jiangsu Province,while an opposite tendency was found in winter;(5) there was a stable group composed of South Yellow Sea population and East China Sea population in some areas near the south of Yangtze River estuary all through the four seasons;(6) the groups reaching the stage of sexual maturation migrated to the target area,spawning and hatching in spring,and there was a high group density of juveniles in summer,nevertheless,there was a dispersing tendency of juvenile groups gradually as the target area was not a stable feeding ground.

Abstract:Statolith is an important hard tissue in cephalopod,which may better reflect the ecological information.Illex argentinus located in the southwest Atlantic is one of important economic cephalopods in the world,which is also one of the important fishing targets for Chinese squid jigging fleets.Mastering the basic biological characteristics and revealing the life cycle process of Illex argentinus is the base for scientificalty developing and exploiting Illex argentinus. According to the samples of Illex argentinus totaled 560 in number collected by Chinese squid jigging vessels from 2007 to 2008 in Southwest Atlantic Ocean,the total statolith length(TSL),maximum width(MW),dorsal dome length(DDL),ventral dorsal dome length(DLL),lateral dome length(LDL),rostrum lateral dome length(RLL),rostrum width(RW),rostrum length(RL),wing length(WL)and wing width(WW)are considered as the indicator of dome growth,and the ratios of MW to TSL,RW to RL and WW to WL are considered as the indicator of changes in statolith shape.The dome growth and statolith shape changes effected by sex,gonad maturity and individual size are analyzed by the analysis of variance(ANOVA)and Leastsignificant difference(LSD).The results indicated that the changes TSL,MW,DLL,DDL,RLL,RL,WL and WW between different sexes were significant(P<0.05).For both female and male samples,the changes of TSL,MW,DLL,LDL,WL and WW between different gonad maturity and different mantle length ranges were also significant(P<0.05).However,the ratios of MW to TSL,RW to RL and WW to WL changes in different sexes,different gonad maturity and different mantle length ranges show no significant differences.The results indicated that the mantle length group(301-350 mm)may be the turning point of the growth of statolith.

Abstract:From 2008 to 2010,the artificial propagation and embryonic development observation of Barbus capito were conducted,alkaline-and saline-adapted ability of embryos and larvae were evaluated.The results show that B.capito lays pelagic eggs and reproductive cycle spans a whole year.At the temperature of 19-23 ℃,the response time of induced spawning drug was 21-26 h.The fecundity of the females(1.4-2.3 kg)was about 8×10⁵-1.4×10⁶ eggs.The induced spawning rate,fertilization rate and hatching rate were 63.9%,81.5% and 86.6%,respectively.The eggs of B.capito were offwhite and the maximum egg diameter was 4.5 mm after absorbing water.At temperature of 20-23 ℃ the accumulated temperature was 49.82 ℃·d from fertilization to the hatchingout larva,and 125.14 ℃·d to the floating-up larva.The length of larva,just hatching out,was(6.07±0.18) mm,and the length of larva,just floating-up,was(8.30±0.47) mm.The saline-alkali tolerant experiment showed that there was no impact on survival rate of embryos(72 h)when salinity was below 3.2 and alkalinity was below 14.32 mmol/L,and there was no impact on survival rate of larvae(96 h)when salinity and alkalinity was below 5.1 and 14.32 mmol/L respectively.

Abstract:The c-Jun N-terminal kinases(JNKs)are the members of the mitogen-activated protein kinase(MAPK)family and play important roles in mediating the environmental stress responses.Previous studies have shown that JNKs regulate development of vertebrates,especially axis development.Our recent studies have also shown that JNK1 is implicated in control of sex reversal of the ricefield eel.To further explore the functions of JNKs in control of development,we have cloned jnk3 from goldfish,and compared the tissue-specific and temporal expression patterns in both goldfish and zebrafish.Our results show that the full length of jnk3 cDNA from gold fish contains an open reading frame(ORF)of 1 293 bp coding for a deduced protein of 414 amino acids.The goldfish jnk3 cDNA is 94.1% identical with that from zebrafish,and 80.7% with that from human.The amino acid sequences are 99.7% identical between goldfish and zebrafish,and 93.4% between goldfish and human.jnk3 is highly expressed in the brain and to a much less degree,in the testis of adult goldfish.In zebrafish,jnk3 is also expressed in the two tissues with similar pattern.In addition,jnk3 is expressed at moderate level in the heart of zebrafish.During development of goldfish and zebrafish,jnk3 mRNA is initially detectable at the neurula stage,then has gradually increased from neurula to heart-beating stage,and maintains at high level from heartbeating to hatching larvae.Together,these results suggest that jnk3 may be important for the later development of fish embryos and also functions in adult tissues including brain,heart and testis.

Abstract:A comparative study was conducted on muscle nutritional component and nutritive quality between pond-and cage-reared paddlefish Polyodon spathula.Pond-reared fish were fed with commercial diet while those of cagereared ones took natural diet,i.e.,zooplankton.The results showed that pond group contained significantly(P<0.05)higher crude protein and crude ash and lower crude fat than cage group.The constitutional rate of essential amino acids met the Food and Agriculture Organization of the United Nations/Word Health Organization(FAO/WHO)standards and the content of Lys was highest in essential amino acids in both pond and cage groups.The content of total delicious amino acids(∑DAA)in pond group was significantly lower than that of cage group(P<0.05).According to nutrition evaluation in amino acids score(AAS)and chemical score(CS),the first limited amino acids were Val and Met+Cys in both pond and cage groups.The content of ∑MUFA in pond group was significantly higher than those of cage group(P<0.05),while contents of ∑SFA and ∑PUFA were lower than that of cage group(P>0.05).The percentages of ∑n-3PUFAs/∑n-6PUFA and EPA+DHA in pond group were significantly lower than those of cage group(P<0.05).It is concluded that paddlefish reared with natural diet could be considered to be higher valued fish for human beings than that fed with commercial feed.

Abstract:An 8-week growth trial was conducted to evaluate the effects of an animal protein blend(APB)with poultry byproduct meal,meat and bone meal(beef),spray dried blood meal,and hydrolyzed feather meal at the ratio of 40∶35∶20∶5 to replace low temperature steam-dried fish meal with or without supplementations of lysine,methionine and threonine in diet of juvenile Japanese sea bass, Lateolabrax japonicus,on growth performance and body composition.Three replacing levels were designed at 50%,75% and 100%,respectively.Growth performance of fish was reduced with higher APB inclusion levels; Fish fed control diet showed significantly higher survival feeding rate(FR),specific growth rate(SGR)and protein efficiency ratio(PER)than those fed diets containing levels of APB; Supplementation of crystallized amino acids(CAA)enhanced the feeding rate and growth performance and reduced hepatosomatic index and increased whole body crude protein,crude lipid and gross energy.Interactions of CAA supplementation and fishmeal replacing levels on growth performance and body composition were significant.Results demonstrate that 1) no more than 50% of LT-FM can be replaced by APB in diet of juvenile Japanese sea bass; 2) supplementations of CAA could improve potential of APB replacing dietary fish meals; 3) crystallized amino acids can be relatively efficiently utilized by Japanese sea bass.

Abstract:Microsatellites combined with bulked segregation analysis(BSA)were used to screen the gender differences of 96 individuals(48 for male and female each)from a family of Channa argus.Two gene pools were constructed using 24 individuals for male and female each separately,gene pools were used to scan using totally 140 pairs of microsatellite primers and specific DNA fragments of female gene pool were amplified by 3 pairs of primers(HLJWL17,HLJWL59,HLJWL70).Then,the specific DNA fragments amplified by the three pairs of primers were verified for the first round in the 48 individuals constructing the gene pools,showing that the specific bands of HLJWL17 and HLJWL70 in gene pools only appeared in few individuals,while HLJWL59 was successfully amplified in females.And in the second round verification,the same results were obtained in the remaining 48 individuals with the HLJWL59.The amplified fragments by primer HLJWL59 of eight different alleles in females were cloned and sequenced.Sequence alignment of the eight individuals using Vector 8.0 multiple confirmed that the bands of each individual are the same sequence,with the sequence length of 243 bp.The repeat units were TGC,and 51% of GC.Compared by the BLASTn,homologous sequences were not found in the GenBank database.According to the statistics,the probability of different bands that appeared in the female C.argus was 62.5%,that is,the correct classification rate of the marker for female C.argus was 81.25%.We believe that this microsatellite loci may be associated with C.argus female gender under certain conditions.This study may serve as a basis for culturing pure male hybrid using female-specific DNA fragments in C.argus.

Abstract:Half-smooth tongue sole(Cynoglossus semilaevis)is a commercially important cultured marine flatfish,in which females grow faster than males.However,under culture conditions,male ratio is higher than female ratio in the half-smooth tongue sole.To find out the reason,one half-smooth tongue sole family is reared for 65 days,from 64 to 129 days postfertilization(dpf)at 17.5,19.5,21.5,23.5,25.5 and 27.5 ℃,respectively.The body size(body length and weight)of the fish was measured on 64,80,103,118,129 and 198 dpf,respectively,and then the relationships between temperature and body size were analyzed by ANOVA and Student-Newman-Keuls.The result showed that the growth rate of tongue sole increased with the increase of temperature from 17.5-25.5 ℃(P<0.05)and then decreased at 25.5-27.5 ℃(P<0.05)on 198 dpf.The Pearson correlation coefficient of temperature and the body lengths and weights of tongue sole were 0.553 and 0.809(P<0.01),respectively.Moreover,the relationship between temperature and the body lengths and weights of tongue sole were described as equations L=2.460 7t^{0.997 9}(R²=0.362 8)and W=9.0×10^-5t^{2.97 6} (R²=0.789 5),respectively.In addition,the gonads of half-smooth tongue sole were analyzed by morphological examination and histological sectioning on 198 dpf.The sex proportions and correlations between temperature and sex determination were analyzed by the method of ANOVA.The result showed that,low temperature(17.5-25.5 ℃) produced a higher proportion of males(27.04%-35.60% females,P>0.05;60.19%-71.53% males,P<0.05).When reared at 27.5 ℃,the proportion of female was up to 53.42%(P<0.05),but 43.49%(P<0.05)of males.At 17.5-27.5 ℃,the temperature was positively correlated with the female(0.349),and the male was negatively correlated(-0.234).The study suggests that temperature plays an important role in the process of sex differentiation and growth of the halfsmooth tongue sole.

Abstract:Currently,the research on Ruditapes variegata has focused on breeding,mantle tissues,pesticide residues,etc.There has rarely been reported about comprehensive nutrition analysis and evaluation of Ruditapes variegata.In this paper,general nutrients(moisture,crude ash,crude protein and crude fat),amino acids,fatty acids,mineral elements as well as vitamins in edible part of R.variegata were investigated.The examination results showed that the contents of moisture,crude ash,crude protein and crude fat in fresh edible part of R.variegata were 82.70%,2.63%,9.63% and 0.54%,respectively.The content of crude fat was lower than Cyclina sinensis,Mercenaria mercenaria, Ostrea rivularis,etc.Eighteen common amino acids were found in the edible part of R.variegate.In dry sample,the total content of amino acids(TAA)was 52.86%;the contents of essential amino acids(EAA),halfessential amino acids(HEAA)and nonessential amino acids(NEAA)were 21.58%,6.82% and 24.46%,respectively;the content of delicious amino acids(DAA)was 18.89%.The ratio of total essential amino acids to total amino acids(W_EAA/W_TAA)was 40.82%,and the ratio of total essential amino acids to total nonessential amino acids(W_EAA/W_NEAA) was 88.23%.It was clear that the constitutional rate of the essential amino acids met the Food and Agriculture Organization of the United Nations/World Health Organization(FAO/WHO)Standards.According to nutrition evaluation in amino acids score(AAS),the first limited amino acid was Met+Cys and the second limited amino acid was Ile.According to nutrition evaluation in chemical score(CS),the first limited amino acid was Met+Cys and the second limited amino acid was Trp.The essential amino acids index(EAAI)was 73.83,which was much higher than M.mercenaria (67.91).Twenty common fatty acids were found in the edible part of R.variegate,including 7 saturated fatty acids(SFA),6 mono-unsaturated fatty acids(MUFA)and 7 poly unsaturated fatty acids(PUFA).the contents of SFA,MUFA and PUFA were 46.12%,24.14% and 29.74%,respectively.In PUFA,the contents of EPA and DHA were totally 67.82%;the content of ω-3PUFA was rich,which was much higher than ω-6PUFA.The composition of mineral elements in the edible part of R.variegata was reasonable.The trace elements such as Fe and Se were richer than those in Meretrix lusoria and Corbicula fluminea.The contents of V_A and V_B2 in vitamins were richer than Pinctada maxima and P.margaritifera; the content of V_B5 in vitamins was richer than M.mercenaria.In conclusion,this investigation indicated that R.variegata is a nutritive and delicious shellfish,and it could be a potential aquaculture species.

Abstract:Fragments of the nuclear ribosome(ITS)and the chloroplast(matK and rbcL)regions were successfully suitable for phylogenetic relationship analysis.With sequencing by PCR amplification,the paper analyzed the phylogenetic relationship of 5 Zosteraceae species(Zostera marina,Z.japonica,Z.caespitosa,Z.asiatica and Phyllospadix iwatensis),which were collected from Ireland,Japan,Korea,China and GenBank.Partial nucleotide sequences of matK, rbcL gene and ITS were analyzed for five Zosteraceae species,and nucleotide composition analysis indicated a strong bias against cytimidine(C)in three fragments.172 nucleotide substitutions were found in ITS fragment,showing the high genetic polymorphism.52 nucleotide substitutions were checked in matK gene and 20 nucleotide substitutions were checked in rbcL gene,most of them were synonymous transitions at the third codon positions.The five species had a certain degree of differentiation at the amino acid level.Based on partial sequences of matK, rbcL and ITS gene,phylogenetic trees were constructed by NJ,MP,ML and Bayes methods and the results were consistent and the phylogenetic trees showed three separate lineages.The minimum pairwise divergences percentage in the samples of Z.japonica and other Zostera species was 19.33% and much higher than the standard(9.60%-28.80%)among genera of most angiosperm and it would be the generic rank from the molecular data.Based on the synonymous nucleotide substitution rate of the rice chloroplast genome matK combined with rbcL gene,we estimated the divergence time between 5 Zosteraceae species approximately arranged from Eocene to Pliocene.The ITS sequences of all Z.marina samples were identical,which fell into the same cluster.It was concluded that variation within ITS region of Z.marina was not correlated to their geographical distance,and ITS region was unsuitable for identification of population groups on a regional or oceanic scale.The paper further elaborated phylogenetic relationship of 5 Zosteraceae species,and also provided theoretic basis for seagrass phylogeny in China.

Abstract:With the development of aquaculture industry and the community’s increasing attention to environmental protection,aquaculture wastewater reuse has become an inevitable trend.As a key factor in aquaculture wastewater treatment,hydraulic condition plays critical roles in biofilm growth and water flow pattern within the reactors.Researching the relationship between biofilm growth and water flow pattern will be conducive to improve the efficiency of wastewater treatment.In the present study,aiming to know the effect of flow velocity on biofilm growth,four types of polyethylene(PE)biofilm carriers and twelve tubular biofilm reactors with a diameter of 44 mm which were made of acrylic material were chosen.Each kind of the biofilm carrier was enclosed into three tubular biofilm reactors and lashed with flow velocity of 0.15 m/s,0.25 m/s,0.35 m/s,respectively,the biofilm carrier’s loading height was 40 mm,flow velocity was controlled by plastic flowmeters and the pipe connection used polyvinyl chloride(PVC)pipes and transparent plastic hose.In order to avoid suspended solids(TSS)in aquaculture wastewater having an impact on the experimental results,this study used artificial water,the concentration of NH₄-N was 2 mg/L,DO was 6-9 mg/L and pH was 7-8.At the same time,the flow pattern of Diversion Moving Bed Biofilm Reactor was simulated by Computational Fluid Dynamic software to observe the state of water flow at different aeration rates.After sixty days,the biofilm thickness of different types of biofilm carriers in different flow velocity were observed with electron microscope.The result showed that the biofilm thickness decreased with the increasing of flow velocity,the thickest biofilm with the thickness of 70 μm occurred at the lowest velocity of 0.15 m/s and the thinnest biofilm with the thickness of 20 μm occurred at the highest velocity of 0.35 m/s.There were no significant differences in biofilm thickness among different structures of biofilm carriers.When the simulation of aeration rate of reactor was set at 0.6 m/s,its integrated flow pattern and biofilm growth situation were the best,the flow velocity in downflow area was 0.06-0.12 m/s and in upflow area was 0.24-0.3 m/s,the eddy area accounted for 10%.The data indicated that the hydraulic condition rather than the structures of biofilm carriers with same material was related to biofilm growth,and low flow velocity is favorable for biofilm growth.Besides,the aeration intensity and reactor’s structure are important factors affecting the Diversion Moving Bed Biofilm Reactor’s flow pattern.This study provided basic data about design and operation for such reactors,and it could be very practical to use the method of combination of experiment and simulation to study biofilm growth and flow pattern,and the data and the method could also be applied to a variety of fields.

Abstract:The contents,distributions and variation features of heavy metal Cd,Cu,Pb,As,Hg and Zn in oyster samples collected from the coast of the South China Sea in 2009 were discussed,and the dietary exposure of heavy metals were calculated using point estimate.It showed that the contents of copper,zinc and cadmium in oyster samples were high and the contents of mercury,arsenic and lead were low,and their contents were 92.0,268,1.32,9.21,0.11 and 0.26 mg/kg(wet weight),respectively.The statistics results showed that the contents of cadmium,copper,lead,mercury,arsenic and zinc in oyster samples had obvious variation with sampling areas and cultivation seasons.Compared with the limit values of the safety requirements for nonenvironmental pollution aquatic product,the contents of copper,zinc,lead,mercury and arsenic in oyster samples were lower than the limit values,while the content of cadmium was higher than the limit value.The increased intake of bioavailable zinc reduced excessive cadmium absorption because oysters were rich in zinc with the low ratio of cadmium and zinc content.Therefore the cadmium in oyster samples was not harmful to health.The assessment results showed that the dietary exposures of heavy metals in oysters were lower than the recommended values of the Joint FAO/WHO Expert Committee on Food Additives(JECFA).

Abstract:Chinese mitten crab, Eriocheir sinensis grows in freshwater habitats until maturity and then migrates into saline waters to spawn.Although it is regarded as an invader causing great ecological and economic loss in European and American countries,the mitten crab has long been a fashionable table delicacy in autumn in China,Japan and other Asian countries.The study was carried out to investigate the changes of external morphological character and some metabolism enzyme activity during the embryonic development of E.sinensis at water temperature(16.2±1.5) ℃ and salinity 20 through laboratory experiment.The results indicated that the process of embryonic development could be divided into nine stages:fertilized eggs,cleavage stage,blastula stage,gastrula stage,eggnauplius stage,eggmetanauplius stage,original zoea stage,prehatching stage and hatching stage.There were significant differences in external morphological character of each stage during the whole process.The whole incubation period is about 40 days at water temperature 16 ℃ and effective accumulative temperature reached 10 758 h·℃.The activity of LDH,total ATPase and MDH changed with the developmental stage of embryos,LDH activity increased first and then dropped with the developmental stage,the highest activity occurred at blastula stage;total ATPase activity was the highest at original zoea stage and was the lowest at gastrula stage; the activity of MDH was the highest at original zoea stage and was the lowest at blastula stage,respectively.

Abstract:Phenanthrene(PHE)is one of PAHs(polycyclic aromatic hydrocarbons)and has toxic effects on aquatic animals after being released into the natural water,and crimson snapper(Lutjanus erythopterus)is one of Osteichthys species and an important link of ecosystem in south China sea.In order to understand the toxic effects and mechanism of PHE on L.erythopterus,an acute semistatic toxic test was carried out,and the oxidative stress relative indicators(activities of SOD and content of MDA in liver and gills,activities of AChE in brain)were investigated with crimson snapper(L.erythropterus)exposed to phenanthrene with different concentration(0,10.0,50.0,250 μg/L)for 96 h.The results showed that 24,48,96 h LC₅₀ values were 4.65,3.46,3.17 mg/L,respectively,and its safe concentration(SC)of PHE on crimson snapper was 0.317 mg/L.After being exposed for 96 h,SOD activities of the liver and gills followed an induced trend with 10.0 μg/L exposured.it was inhibited firstly and then induced with 50.0 μg/L and 250 μg/L in the liver,however it was followed the inhibited-inducedinhibited trend of that in gills.The MDA content in the liver and gills has been increasing with time passing,and this also illustrates that the injury degree rose.AChE activity in brain was induced when crimson snapper exposed to low phenanthrene concentration,however inhibited when exposed to higher concentration and it illustrates that phenanthrene could do harm to neurotransmission in fish brain.It is indicated that PHE has performed a higher toxic effect on L.erythopterus,SOD,AChE activities and MDA contents are probable for being the bio-indicators to the phenanthrene pollution because of their higher sensitivities,and could provide information about monitoring and managing of fishery resources.