Abstract:The study aims to evaluate the effects of dietary emodin, high-dose vitamin C (Vc) and their combination on the disease resistance of Aeromonas hydrophila infection. One thousand and two hundred healthy fish with initial body weight of (133.44±2.11) g were selected and randomly divided into four groups: one was the control group fed with basal diet (containing Vc 50.3 mg/kg, with the L-ascorbyl-2-polyphosphate as Vc source); the other three were the treatment groupsnted with emodin 60 mg /kg, Vc 700 mg/kg, and the combination of emodin 60 mg/kg + Vc 700 mg/kg, A. hydrophilathe biochemical parameters of serum and liver, the mRNA levels of two heat shock protein 70s (HSP70s) in liver infection were determined. Another ten fish taken from each tank were challenged with using the same method as above, and the cumulative mortality of each group was counted at different time of post-infection. The results showed that before infection, compared with the control group, serum total protein (TP), lysozyme (LSZ) and alkaline phosphatase (AKP) levels, liver superoxide dismutase (SOD) activity and expression level of inducible HSP70 mRNA significantly increased , while serum cortisol (COR), triglyceride (TG) and liver malondialdehyde (MDA) contents decreased ( <0.05) in emodin and Vc groups; the liver catalase (CAT) activity also significantly increased in <0.05). Although the serum TP, LSZ and liver HSP70 mRNA levels significantly increased , and the liver malondialdehyde (MDA) level was also significantly reduced (<0.05), no synergism was shown.After infection, compared with the control group, the serum TP, LSZ, AKP levels, liver SOD, CAT activities, and the expression levels of HSC70 and HSP70 mRNA increased in varying degrees, while the serum COR, glucose (GLU), combination group, although these parameters had similar changing trend as the above ones, most of them were not significant different with the control (> 0.05), and also did not . Statistic data also showed that after infection with A. hydrophi1asignificantly lower than the control group was not significant (> 0.05). could improve non-specific immunity of fish, capacity, and two HSP70s mRNA expression However, the combination of emodin and high-dose Vc showed no better effect, and the mechanism of their interaction

Abstract:Based on data from 14 bottom trawl surveys in the Bohai Sea and the southern Yellow Sea during spring (from April to May) of 1960−2004 and spring of 1960−2010, inter-annual changes on body weight-length relationship () and relative fatness of two geographical stocks of small yellow croaker [the northern Yellow Sea-Bohai Sea stock (NYBS) and the southern Yellow Sea stock (SYS)] and their impact factors were analyzed. was linearly regressed by logarithm-transformed body length and its corresponding mean body weight; relative fatness was computed by relative weight by years, sex and stocks. The results showed that the allometric factor() was not significantly different between sexes in most years, and significantly negative correlations (b in two stocks. The (lg ratio may be connected with fish body density, and its value was little influenced by environment. The values almost approached 3, which indicated isometric growth in the NYBS stock in most surveys from 1960 to 2004, and they increased during the regression stage and the early recovery stage of the stock (1982−1993). However, most of <0.05), indicating strongly negative-allometric growth in the SYS stock from 1960 to 2010, and they decreased during the regression stage and the early recovery stage of the stock (1986−1994), then increased since the late 1990s. The highest relative fatness of small yellow croaker was found in 1960 in the two stocks. The fatness clearly decreased in total from 1960 to 2004 in both male and female fish in the NYBS stock, and it significantly declined from 1960 to 1986 in the SYS stock (<0.05), then slightly and insignificantly increased since the mid-1990s in both male and female fish in the SYS stock (>0.05). According to analysis, based on better food conditions, the relative low fishing pressure was the main reason for the isometric growth of the NYBS during the 1980s and the early 1990s; and the continually heavy fishery increased the proportion of low age fish and the growth speed in the SYS, which may be the main reasons for the negative-allometric growth of the stock. The decrease in age at maturity may be the reason of the decline in the relative fatness in both stocks, but the closed seasons and the relative higher water temperature in the southern Yellow Sea made the relative fatness increase since the mid-1990s in the SYS.

Abstract:, a large anadromous species, mainly distributes in the continental shelf of the East China Sea and the main steam of Yangtze River. From July to August in each year, the pre-spawning individuals enter into the Yangtze estuary. Then they go against the water flow and will spawn in autumn of next year. The spawning locus is about 1 700 km away form the Yangtze estuary. After hatching, the yolk-sac larvae go downstream with the water flow and will arrive at the estuary in April and August of next year. Xupu, Changshu, a place at the Yangtze estuary, is a good site to monitor juveniles. So in years from 2002 to 2009, by a fixed stow net (set by the Yangtze Fishery Resources Commission for fishery monitoring) set in this site, we investigated the resources of juveniles. It was indicated that the emergence of the fish at Xupu, Changshu mainly occured from May to July, with the average period being 86.6 days (=8) average total length, body length and body weight were 25.2−40.1 cm, 23.2−314.8g, respectively. The numbers of specimens captured in each year were very different, and a decreasing trend occurred from the year 2002 to 2009. The periods (ten days as a unit) with maximum sampling number were also different, which ranged from the second ten days of May to the last ten days of June. The sizes of the juveniles were very different in the same period of different year, and the sizes of the specimens captured in the same year and same date also showed difference. Compared with the study in the four years (1987, 1990, 1991 and 1992) before the closure of the Three Gorges Dam, the time range that juveniles arrived at the Yangtze estuary showed no obvious difference(>0.05). However, the occurrence proportion in each ten days during the time from May to July varied. The high occurrence proportion was mainly in June before the closure, but after the closure it also occurred in May. The size of the juveniles was also different from pre-closure. It was speculated that the difference was caused by artificial enhancement and releasing, and variation of hydrological regime. ydrological condition was an important factor influencing the time consumption for the fish to migrate from spawning area to the Yangtze estuary.

Abstract:The historical data of fish survey in Dongsha Islands, Xisha 514 species were recorded in Dongsha Islands, 620 in Xisha & Zhongsha Islands, and 548 in Nansha Islands, respectively, which were less than expected and also below the average number in other reef waters elsewhere which have similar habitats with South China Sea. Additionally, we calculated the fish taxonomic diversity indices: the average taxonomic distinctness indices △⁺ in Dongsha, Xisha & Zhongsha and Nansha Islands were 55.1, 60.2 and 56.6, respectively; variation in taxonomic distinctness index were 121, 164 and 150 in those islands, respectively. All △⁺ values were lower than that of the continental shelf waters of East China Sea, while all values were higher than it. Regarding the species' and family's taxon level, we calculated the similarity coefficients between reef waters of South China Sea and Calamine Islands, Milne Bay, southwest continental shelf waters of Nansha Islands and northern continental shelf waters of South China Sea. The results indicated that there is greater difference in similarity coefficients on species level between Xisha & Zhongsha Islands and the other reef waters, but less difference occurred on family level, and all similarity values on species and family level are higher in reef waters than those in continental shelf waters. Moreover, with Kruskal-Wallis detection, we studied the relative species richness of associated reef fish families in South China Sea reef areas, Calamine Islands and Milne Bay, but no significance difference were found. Hihgter species diversity and lower taxonomic diversity are the main characteristics of large scale distribution patterns of diversity of fish in coral reef waters, South China Sea.

Abstract:Seasonal characteristics of cadmium were studied in the Pearl River estuary from February to November, 2008, including distribution of cadmium in water bodies, sediments and aquatic animals. For water samples, 1L water was collected from 0.5 m below surface and fixed with 2 mL hydrogen nitrate. For sediment samples, the surface bottom mud was collected with grabtype sediment sampler and saved in sealed bag. For organism samples, we just selected muscle of the fish and shrimp and saved different species in its own sealed bag. The above sampling processes were all in accordance withThe water samples were processed with resolution method according to National Standard (GB/T 7457-87) and the sediment samples were also processed with resolution method according to National Standard (GB/T 17137-40 1997). The mud was treated in the following sequence: cleared off sundries, air-dried, and grinded. The homogenate of organism muscle was processed according to National Standard (GB/T5009-2003). All the processed samples were detected with Varian SpectrAA 400Our results indicated that the cadmium concentration in water bodies ranged from 0.022 mg/L to 0.047 1 mg/L, with an average of 0.012 8 mg/L. The highest value appeared in February, while the lowest value appeared in August, with the sequence of February, May, November and August. According to the Environmental Quality Standards for Surface Water GHZBI, our results showed that water quality of the studied area was worse than Class III water quality standards. The cadmium concentration in sediments ranged from 5.062 mg/kg to 9.239 mg/kg, with an average of 6.974 mg/kg, which was higher than those in other estuarine areas, and showed a steady increasing trend. The cadmium concentrations in aquatic animals ranged from 0.144 mg/kg to 0.430 mg/kg, which were higher than the national limiting standard. Furthermore, the cadmium concentration in predatory fish was relatively higher than that in omnivorous fish. Compared with previous studies in Pearl River estuary, we found an apparent increasing trend for cadmium concentration in fish bodies during recent years.

Abstract:of a single HDPE gravity cylindrical cage wereperimeter and a ss = 1/2. out Ocean Engineering Basin of Institute of Industrial Science of the Tokyo geometrically similar to the proto type. The horizontal projections of the front mooring lines in the same direction of current or incident waves. Uniform current /s Regular waves with a period and a height Under the actions of current only, the tension in the front mooring lines wavethe tension in the rear mooring lines was greater than that in the front mooring liness deduced. It turnwaC₁ and are constants). (3) Under currentagain greater than and are constants).

Abstract:According to gene sequences, penaeidins (one kind of antibacterial peptide in shrimps) in genome of Chinese shrimp, is, could be assorted into three kinds. In order to explore the expression differences among the three penaeidins after WSSV challenge, real-time quantitative PCR was used to detect the expression characteristics of these penaeidins at different time after WSSV challenge in Chinese shrimp. hrimps used in the experiment came from the same parentage. After fed each individual the same dose of WSSV, 3−6 samples were collected at 0 h (uninfected), 6 h, 12 h, 24 h, 48 h, 72 h, 96 h, 120 h and 156 h after infection. The individuals dying in three days were regarded as WSSV-susceptive population, while those still living after seven days were regarded as anti-WSSV population. The results showed that the expression of penaeidins was tissue specific in four tissues of hepatopancreases, muscles, gills, and intestines, and the richness of expression and expression tendency from 0 h to 156 h was significantly different (<0.05). However, as far as one tissue was concerned, the tendency of expression for three penaeidins was similar in the period from 0 to 120 hours after challenge. For example, the expression of three penaeidins’ mRNA in hepatopancreas was 0 at 0 h, and increased at 6>0.05). It seemed that the penaeidins of shrimps might mainly take part in resisting bacteria, not in resisting WSSV.

Abstract:During October, 2009, a serious infectious disease began to break out in cultured largemouth bass() of Foshan area in Guangdong province of China. Affected fish had following clinical signs including slowly swimming, floating at the surface of water, pale gill, swollen liver, spleen and kidney, pale liver and dark red spleen. Transmission electron microscopy of the focus liver, spleen and kidney revealed numerous cytoplasmic, icosahedral virion without envelope. The diameter of the virion was about 156−160 nm. Filtrate dilutions of liver, spleen and kidney were inoculated onto the monolayers of EPC, FHM and CIK cells respectively, but cytopathic effect(CPE) was not observed at the 8th days after infection. According to known gene sequences of iridovirus, special primers were designed to amplify the gene of the current virus. Liver, spleen and kidney DNA was extracted as PCR templates. PCR products were sequenced and the nucleic acid sequence of viral MCP gene is 98% identical to those of ISKNV (Infectious spleen and kidney necrosis virus) and DGIV (Dwarf gourami iridovirus), and the amino acid sequence is 99% to those of them. Transmission electron microscopy and gene sequence of the virus indicated that the pathogen is a virus of genus , family Iridoviridae. Experimentally infection for healthy largemouth bass with filtrates of tissues by intramuscular injecting caused a more than 90% mortality and the signs of the infected fish were similar to those of natural infection. In contrast, control fish exhibited no mortality and no clinical signs of infection. LMBV was a ranavirus isolated from diseased largemouth bass in USA. Naturally infected largemouth bass with LMBV appeared normal and lacked external lesions, but they floated at water’s surface with an enlarge swim bladder. A similar ranavirus was isolated in China in 2008, and its predicted amino acid sequence was 98% identical to corresponding sequence of LMBV, and naturally infected largemouth bass with the virus were all characterized by extensive ulceration in skin and muscle. Different from the symptoms of the above viruses, largemouth bass infected by the currently megalocytivirus exhibited swollen liver, spleen and kidney. All of the three viruses could cause death of largemouth bass, but the clinical signs of the infections were different. This study is the first report on largemouth bass naturally infected by megalocytivirus

Abstract:In this study, a nested PCR for detecting soft-shelled turtle iridovirus (STIV), wo pairs of primers were designed based on the sequence of major capsid proteins (MCP) gene of STIV by The outer primers were P1 (5′-′CGCGATAGGCTACTAT AACATGG). The first round PCR was carried out using PCR Supermix with 40 ng template DNA, 0.6 µL primers (P1/P2, 50 pmol/µL), 2 µL PCR buffer with MgCl₂, 0.5 µL Tag, and dH₂O was added to reach total volum of 20 µL. The conditions of PCR were: 94 PCR was carried out by using the same supermix except 0.5 µL template DNA, the product of first round PCR, 0.6 µL primers (P3/P4, 50 pmol/µL). The conditions were the same with the first round PCR. In this study, a standard recombinant plasmid was produced to in PCR assay. The DNA products of first round PCR were extracted, and then cloned into pGem-T Easy vector. After sequencing, the -S were used in ranavirus detection as the position control. Specificity and sensitivity of the PCR method were estimated. Data showed that the detection limit of this assay was 10² copies for standard recombinant plasmidIt was also found that the specificity of this assay was high without any cross-reactions with DNA from Infectious haematopoietic necrosis (IHNV), Spring viraemia of carp virus (SVCV), Viral Haemorrhagic Septicaemia virus (VHSV), Channel catfish virus (CCV), Infectious pancreatic necrosis (IPNV), Red sea bream iridovirus (RSIV), Hirame rhabdovirus (HRV), Koi Herpesvirus (KHV) and Infectious spleen and kidney necrosis virus (ISKNV) provided bySTIV, EHNV and TFV DNA could result in the same pattern of curves with the two primers. confirmed that the PCR assay is a powerful tool for the detection of ranavirus with high sensitivity and specificity. Moreover, the is of low cost and time saving in contrast to ELISA assay, . So the Nest-PCR method could be used to detect these three kinds of ranavirus efficiently.