Abstract:Based on the bottom trawl data in May and August, 2010 in the Bohai Sea, combined with the fishery data and literature in the Bohai Sea since 1959, the succession of fish community structure and the stock dynamics of main releasing fish species in the Bohai Sea were analyzed. The shift of dominant species was rapid, and large sized, high trophic level species (e.g. Trichiurus haumela, Cynoglossus semilaevis and so on) were replaced by small sized and low trophic level species (Setipinna taty, Engraulis japonicus and so on). Rapid shifts in small sized fish species were also found in fish community in recent years, excluding Setipinna taty, which was the dominant species in fish community since the 1980s. In addition, fish community structure was in a fluctuating state versus time according to the analysis of biology healthy index. Fish catch per unit effort in May sharply decreased from 186 kg/h in 1959 to no more than 1 kg/h in the present. Fish stock mainly distributed in the Laizhou Bay, Bohai Bay, and the central part of the Bohai Sea,but much less in the Liaodong Bay, and staggered biomass distribution were found between fish and jellyfish. The biomass of releasing fish species Lateolabrax japonicas and Sebastes schlegeli increased slightly in recent surveys, but that of other releasing fish species showed a decreasing trend since the 1980s. The biomass of a few releasing fish species was restored to some extent by stock enhancement, yet still less than 1% of the maximum biomass in history (excluding L. japonicas). Fish community in the Bohai Sea was dominated by small sized and low trophic level species, indicating that a lot of work needs to be done for stock enhancement.

Abstract:Eighteen morphological traits of Fugu rubripes Temmincket Schlegel were studied. The phenotypic parameters of these traits and the coefficients of correlation among them were computed. The hierarchical principal component analysis and cluster analysis were employed to select the representative traits in the fish. The results of principal component analysis and cluster analysis were consistent， indicating that five body traits， including body weight, body girth 1, body length, length between eye and head, eye diameter should be considered for morphological selection. The results of the two methods will provide references for body traits selective breeding for F. rubripes.

Abstract:The post embryonic morphological development of Hexagrammos otakii was observed, measured and recorded by a micro cinematographic system to explore the morphological development characteristics in different stages of larval and juvenile fish. Newly hatched larvae, 6.18±0.50 mm long and depending entirely on the egg contained energy, were nursed at 16.0±0.5℃, salinity 31, illumination 500～1 000 lx. At 3 dph (days post hatching), 7.55±0.27mm in length, with the rudimental yolk sac at abdomen, some larvae started feeding rotifers, and the development entered the exogenous feeding stage. After yolk was exhausted at 6 dph, the larvae started feeding Arternia nauplii. At 48 dph, the larvae started feeding compound feeds. The relationship between total length (TL) and days post hatching (D) for 0~7d，7~48d，and 48~80d fish was described as: TL(0～80) = -0.000 2D3 + 0.028 1D2 -0.155 7D + 7.376（R2 = 0.993 9）; TL（0～7）= 0.004 6D3 -0.057 2D2 + 0.383 1D + 6.175 1（R2 = 0.997 1）; TL（7～48）= 0.000 5D3-0.026 7D2 + 0.931D + 2.269（R2 = 0.997 3）; TL（48～80）= -0.0001D3 + 0.018 7D2-0.204 5D +24.646（R2 = 0.999 8）.

Abstract:In humans (and probably other mammals)，it is generally agreed that there are five basic taste qualities: sweet, bitter, umami, salty and sour. Recent compelling evidence from rodent and human studies raise the possibility for an additional sixth taste modality devoted to the perception of lipids (fat taste). It has been shown that zebrafish can perceive amino acids, bitter tastant as taste stimulants，then what about fat taste?Until now，it has not been reported yet. Based on this, behavioral experiments were conducted to detect the existence of fat taste in Danio rerio and Pangasius sutchi. It was shown that fish can perceive not only bitter and amino acids tastants, but also fatty acids. In addition, we found that P. sutchi had a preference for sweet taste, which is inconsistent with the previous report that there was no sweet taste in zebrafish.

Abstract:Aeromonas veronii is a kind of pathogenic microorganisms found in the intestinal tract of loach Misgurnus anguillicaudatus, and may result in 60% high mortality. Here， 57 antagonistic bacteria strains against A. veronii were isolated from the samples collected from aquaculture water, sludge and intestine of healthy and sick loaches. Their antibacterial activities were examined by cylinder plate method with TSB medium. A bacterial strain, named CMA 1, was screened from them and identified as Bacillus methylotrophicus CMA 1 by morphological observation, physiological characteristics tests, and 16S rDNA sequence analysis. The growth of CMA 1 entered into the stationary phase after being cultured for 24h ,and its antibacterial activity was up to the maximum at 36h. The crude metabolites were separated from fermentation broth through ammonium sulfate precipitation, and their antibacterial activities were examined. The results showed that the antibacterial activity of precipitate at 75% (NH4)2SO4 saturation was significantly higher. CMA 1 would be a useful probiotics in the prevention and control of fish disease caused by A. veronii.

Abstract:Effects of methionine enriched Artemia nauplii on growth performance, main digestive enzymes (amylase, acid protease, and alkali protease) activity, alkaline phosphatase activity and concentration of digestion related hormones (cholecystokinin, thyroxin, triiodothyronine, and cortisol) in Cynoglossus semilaevis Günter (initial length 167±014cm) were studied. Three groups of postlarvae, including methionine group, Schizochytrium group, and methionine+Schizochytrium group, were fed Artemia nauplii enriched with methionine, Schizochytrium, and methionine+Schizochytrium respectively.A control group was fed Artemia nauplii without enrichment. Larvae were cultured for 16 days， sampled and tested at 4 day intervals. Postlarvae in the Schizochytrium treatment showed the highest growth at the end of the experiment；their weight was significantly greater than the control(P<005), and their length was significantly greater than other treatments at 12d. Alkaline phosphatase activity in Schizochytrium treatment was significantly greater than the methionine treatment and the control at 16d (P<0.05), and their alkali protease activity was significantly greater than the other treatments at 16d (P<0.05). The concentration of triiodothyronine (T3) in Schizochytrium treatment was significantly higher than the methionine treatment and the control at 12d (P<0.05). Thyroxin (T4) content in Schizochytrium treatment was significantly greater than the control at 12d (P<0.05). Amylase activity in methionine+Schizochytrium treatment was significantly greater than the methionine treatment at 12d (P<0.05). CCK level of the control was significantly higher than methionine+Schizochytrium treatment and methionine treatment at 4d (P<0.05), and was significantly higher than the other treatments or Schizochytrium treatment at 12d and 16d. No significant differences were found in acid protease activity between four different treatments. Cortisol levels of methionine treatment was significantly lower than the other treatments at 4d, and significantly lower than the control and methionine+Schizochytrium treatment at 8d and 16d (P<0.05). However, alkaline phosphatase, amylase activity, T3 and T4 levels were higher at the earlier stages of the experiment. It is suggested that methionine enriched Artemia nauplii feeding can meet the growth requirement of C. semilaevis larvae.

Abstract:Three experimental diets with fish oil, soybean oil and olive oil as different lipid source and a commercial diet as control were used to feed broodstock of tongue sole Cynoglossus semilaevis for 8 weeks to investigate the effects of different fat source on spawning performance, fatty acids composition in eggs and quality of larvae. Results showed that in terms of the relative fecundity, the control was the highest, followed by olive oil treatment, fish oil treatment, and soybean oil treatment as the lowest. The abnormal egg ratio of control was the lowest follwed by, fish oil treatment, olive oil treatment, and soybean oil treatment as the highest (9.77%, 14.53%, 19.4% and 17.35% respectively)(P＜0.05). Abnormal larva ratio among treatments was significantly different (P＜0.05) (3.34%, 3.12%, 8.85% and 17.35% respectively). Hatching rate of control was the highest, followed by fish oil treatment, olive oil treatment, and soybean oil treatment as the lowest (P＜0.05) (95.49%, 84.88%, 79.57% and 74.27% respectively). It indicated that during spawning period, a certain amount of n 3 HUFA in diet, especially docosahexenoic acid (DHA) needs to maintain egg development and larval growth. Oleic acid and linoleic acid (LA) were selectively retained and played an important roles in tongue sole egg development process. We conclude that soybean oil or olive oil or fish oil as a single lipid source of diets can not provide sufficient fatty acids for tongue sole C. semilaevis.

Abstract:In this study, the feeding habits of Ampithoe valida were analyzed, and its response to different temperature and salinity were observed. It was found that (1) the contents of the digestive tract of A. valida were classified into organic debris and algae;(2) Among the digestive enzymes in the digestive tract of A. valida, the activity of trypsin was the highest, followed by LPS, which was higher than AMS; (3) More rapid growth was achieved when A. valida fed on shrimp pellet diet, compared with diets such as Chaetomorpha antennina, Chlorella,bioflocculant(biofloc) and clam meat diets; (4) Adult A. valida showed greater ability for high temperature resistance than young ones, and this tolerance is related to their living water temperature; (5) A. valida is a euryhaline animal, which can survive a salinity in the range of 4~40.

Abstract:The relationships between 11 morphological characters and body weight of Exopalamon carincauda from three areas, including Haizhou Bay, Xiangshan Bay and Laizhou Bay were investigated. Morphological traits were used as independent variables and body weight was used as the dependent variable in correlation and path analysis.It was found that the correlation coefficients between all the 11 morphological characters and body weight were statistically significant (P<0.01). The path analysis revealed a convincible relationship between the independent variables and the dependent variable. The path coefficients (Pi) of full length, body length, carapace length,telson length,carapace width,1st abdominal segment width to the body weight were all statistically significant,and were crucial to determine the body weight of E. carincauda. Judging from the result of multiple correlation coefficient (R2 = 0.931), the main variables have been selected. Multiple regression equation of X1,X2,X3,X5,X6,X7,X9 and Y was set up as: Y=0.007X1 +0.043X2 +0.044X3 +0.044X5+0.073X6 +0.111X7 +0.057X9 -3.838. This study provided basic data for E. carincauda biology and ideal measuring indicators for its extension as a model species for mariculture.

Abstract:Rab proteins are the largest subfamily in small GTP binding proteins, which play important roles in vesicle formation, transportation, adhesion, anchoring,and fusion. As a member of this family, Rab7 protein is in charge of the delivery of internalised materials into degradative compartments and the acquisition of lysosomal hydrolases. Evidence from the previous studies showed that VP28 of white spot syndrome virus (WSSV) can bind with Rab7 in Penaeus monodon (PmRab7). By rapid amplification of cDNA ends (RACE) method, the full length gene of Fenneropenaeus chinensis Rab7 gene (fcrab7) was obtained. The total cDNA consists of a 615bp open reading frame (ORF), which encoded 205 amino acids with a predicted molecular mass of 23.2 kDa . The deduced amino acid sequence contained many conserved motifs and regions, and the entire protein has 100% homology with Rab7 of Litopenaeus vannamei and P. monodon. The recombined vector of pBAD/gIIIA-fcrab7 was constructed and transformed into E. coli. The fusion protein was successfully expressed by induction, which was tested by SDS-PAGE and Western blot analysis. These results laid a basis for further studies on interaction between WSSV and FcRab7.

Abstract:In this study, a hemocyanin cDNA named EcHc was cloned from the hepatopancreas of the ridgetail white prawn Exopalaemon carinicauda by reverse transcription PCR (RT PCR) and rapid amplification of cDNA end (RACE) methods. The full length cDNA of EcHc was 2 158 bp and had an open reading frame(ORF) of 1 992bp encoding 663 amino acids which contained a signal peptide sequence(1~15 amino acid residues). The predicted molecular weight of the mature peptide was 75.05kDa, and the theoretical pI was 569. The homology analysis of EcHc with other hemocyanin showed higher similarity with Macrobrachium nipponense (86%). Quantitative real time RT PCR analysis revealed that microbial challenge resulted in mRNA up regulation, up to 6h post injection of Vibrio anguillarum or white spot syndrome virus (WSSV). The results indicated that the EcHc plays important roles in the immune defense system of E. carinicauda.

Abstract:The off plate syndrome is an epidemic disease of juvenile sea cucumber Apostichopus japonicus during nursery period, showing severe infection, rapid transmission and high mortality. In this study, epidemiological investigation of off plate syndrome was conducted in several infected hatcheries along the coast of Liaoning Province. A dominant bacteria strain coded Aj2010072802A90 was isolated from the skin of affected juveniles and proved to be the pathogen through the artificial infection tests. The pathogen was identified as Vibrio parahaemolyticus through morphological observation, physiological & biochemical tests and 16S rDNA sequence analysis. This is the first report on V. parahaemolyticus disease in juvenile sea cucumber. Drug sensitive tests were done against the pathogen and revealed that the V. parahaemolyticus strain was sensitive to florfenicol. The result would provide theoretical basis and technical support for disease control and health management in sea cucumber culture.

Abstract:Seven morphometric traits and weight traits of wild Atrina pectinta, including shell length (SL),shell width (SW), shell height (SH), live body weight (WG), tissue weight (WT), adductor muscle weight (WM) and shell dip angle(AG), were measured. The relationships between these morphological traits (SL, SW, SH, and SA) and weight traits (WG, WT, and WM) were evaluated by correlation analysis and path analysis. Traits such as SL, SW, SH and SA were used as independent variables, while WG, WT and WM were used as a dependent variables. It was found that correlation coefficients between morphometric traits (SL, SW, and SH) and weight traits (WG, WT, and WM) were significantly different (P<0.01). Shell height, as a key effective factor, had predominant direct impact and indirect impact on weight traits. Shell length and width, as two secondary factors, showed significant indirect impact through shell height and slight direct impact on weight traits. The morphometric traits having significant impact on weight traits were used to establish the multiple regression equations of WG, WT and WM: Y=69.112SH+52.823SW-751.36, Y=38.485SW-472.912, Y=4.275SH-18.610.The results provide a theoretical tool for genetic breeding study of A. pectinta.

Abstract:Experiments were carried out to explore the function of Chinese herbal medicine as immunostimulants in Scylla serrata. The formula included Astragalus membranaceus, Baicalensis Georgi, Eucommia ulmoides Oliver, and GLycyrrhiza uralensis Fisch in the proportion of 4∶3∶2∶1. The control group was injected with saline, while the experimental groups were injected with liquid formulated Chinese herbal formula medicine. The activity of enzymes in hemolymph firstly increased until the peak appeared 2-day after injection (except SOD), then decreased back to normal level 4-day after injection. The survival rate of treatment groups was improved to 53.33% when S. serrata was subjected to Vibrio parahaemolyticus. It is suggested that this herbal formula may be used as a herbal feed additive and serve as an effective immunostimulant in cultured aquatic animals.

Abstract:In order to further investigate the species and distribution of Zosteraceae along the coast of Shandong Peninsula, ecological survey was performed during August~October, 2011. Based on morphological characteristics, ITS sequences were analyzed to identify the Zosteraceae samples.Three species were found during the survey, namely, Zostera marina L, Zostera japonica Ascherson & Graebner,and Phyllospadix iwatensis Makino. Among them, Z. marina distributed most widely but in different patterns in each place: mottled in Laizhou Bay, sporadic in Huiquan Bay, and in large stretches along the coast of Lidao, Xiaoshidao and Chudao. Z. japonica was found in less bimass, showing a mottled distribution in Laizhou Bayand a sporadic distribution in Guangrao County. P. iwatensis was found only in Shilaoren Beach in Qingdao with a patchy distribution. The survey also revealed that seagrass beds of Zosteraceae along Shandong Peninsula coast have been damaged and have degenerated in various degrees. Along the coast of Lidao, Xiaoshidao, and Chudao, Zosteraceae distributed in large stretches, while in other surveyed areas it showed a patchy or sporadic distribution. Specifically, seagrass beds of Zosteraceae along Rizhao coast seemed to be completely destroyed,and none Zosteraceae species was found.

Abstract:The chlorophyll fluorescence of the blades of three common seagrass species (Zostera marina, Z. caespitosa and Phyllospadix iwatensis) in eastern waters of Chudao, south coast of Sanggou Bay, was determined using the pulse amplitude modulated (PAM) fluorometer. The absorbance factor (AF) of seagrass blades were also determined,and the absolute electron transport rates of the seagrass species were calculated.It was found that the photosynthetic activity of Z. marina, Z. caespitosa and P. iwatensis, was strongly influenced by leaf age. The chlorophyll content and the AF values increased with blade age in respective plants. Young blades showed higher electron transport rate than older ones (Zm: Leaf 1=26.56, Leaf 2=16.3, Leaf 3= 19.98; Pi: Leaf 1 =22.31, Leaf 2=19.23, Leaf 3=17.06; and Zc: Leaf 1=20.16, Leaf 2 =16.10，Leaf 3=13.10). Among three species, Z. marina showed the highest photosynthetic activity (ETRmax=22.67), in accordance with its highest productivity in the field compared with the other two species.

Abstract:The 1527bp IHNV glycoprotein gene was cloned by reverse transcription polymerase chain reaction（RT-PCR）from cell culture, and was subcloned into pCWori plasmid. Then the recombinant pCWori-G was transformed into DH5α. The recombinant protein was obtained through fermentation. The 57kDa target protein was expressed successfully by 1 mmol/L IPTG induction for 5 h. SDS-PAGE analysis showed that it was mainly in the form of inclusion body. The soluble glycoprotein was obtained after purification and renaturation processing. Western blot analysis showed that the recombinant protein was identified specifically by the goat anti IHNV serum. The recombinant protein was used to immunize mice to produce glycoprotein antiserum. The prepared antiserum reacted specifically with IHNV by indirect ELISA test. In this study, the IHNV glycoprotein was expressed by prokaryotic expression system and polyclonal antiserum was obtained by immunized mice.

Abstract:An ion chromatography method with non suppressed conductivity detection was developed for the simultaneous determination of trimethylamine N oxide (TMAO) and its decomposition products (trimethylamine, TMA, and dimethylamine, DMA) in fishery products. Fishery samples were treated with 10% trichloroacetic acid, afterwards the extracted solution was centrifuged and diluted before injection to the ion chromatography device. The targeted compounds were eluted from a Metrosep C4 150 (150mm×4mm) column by 4mmol/L nitric acid with 3% acetonitrile (v/v). The retention time of DMA, TMAO and TMA were 6.22min, 8.21min and 9.09min, and the detection limits were 0.025mg/kg, 0.050mg/kg and 0.050mg/kg, respectively. The coefficients of linear equations were all above 0.999. The RSD were between 1.41% and 3.83% (n=5), and the recoveries were between 91.5%~100.3%. DMA was found in the samples which contain endogenous formaldehyde, while sample without endogenous formaldehyde was DMA free.