Abstract:Histone deacetylase (HDACs) can control cell proliferation and differentiation by regulating the chromatin structure and inhibiting the activity of specific transcription factor.In view of the function HDAC1 played in the process of metamorphosis of tadpole, the expression of HDAC1 during metamorphosis of Japanese flounder (Paralichthys olivaceus) was investigated in this study.The full-length cDNA of HDAC1 gene with 2 540 bp was obtained from P.olivaceus, containing 126 bp-length 5'UTR, 1 470 bp-length ORF, and 944 bp-length 3' UTR.Expression of HDAC1 in coronary dorsal fin is gradually enhanced with the growth of coronary dorsal fin.Its expression on the fin fold was first found from 9 days after hatching (DAH), and later in 18 DAH larvae, mainly was found in the base of fin fold.The gene expression of HDAC1 in intestine increased with the intestinal being shorter and thicker.Then, it began to weaken at 16 DAH and eventually disappeared.The difference of HDAC1 expression between P.olivaceus and tadpole is its expression throughout the process of metamorphosis while only before metamorphosis in tadpole as reported in previous study.During the metamorphosis of P.olivaceus, HDAC1 gene was mainly expressed in pterygiophore, gill and skin around eyes.It expressed higher at the early stages of metamorphosis than later stages.The expression pattern of HDAC1 before and during the process of metamorphosis in P.olivaceus indicates it participating in the development of coronary dorsal fin and intestine, as well as the eye migration during metamorphosis.

Abstract:Cnot2, a subunit of CCR4-NOT, was cloned from the mantle tissue of Pinctada fucata by RACE PCR and named Pf-Cnot2.The complete sequence was 2 616 bp long and the open reading frame was 1 725 bp, which encoded 574 amino acid residues with the theoretical molecular weight of 61 ku and theoretical isoelectric point of 6.25.Protein sequence analysis showed that it was rich in serine, glycine and threonine, and had a conservative NOT2_3_5 domain.Phylogenetic analysis indicated that Pf-Cnot2 had a far evolutionary relationship with Cnot2 of vertebrates.This gene was expressed in tissues of mantle edge, mantle pallial, foot, gonad, visceral mass, adductor muscle and gill in Pinctada fucata, in which, gonad had the highest expression level, followed by gill and mantle pallial.Pf-Cnot2 was expressed during the whole process since trochophore developed into the juvenile shell, and got to its lowest level at trochophore stage.D-shape stage was significantly higher than trochophore stage.The results above provided basic materials for further study of the role that Pf-Cnot2 played in Pinctada fucata.

Abstract:Genetic diversity of eight Procambarus clarkii stocks in Jiangsu Province (Dapu, Pingwang, Qitang, Guantan, Xishunhe, Taiping, Guchen, Yanghetan) was investigated using 8 microsatellite DNA loci.The result showed that all the eight loci were highly or medium polymorphic.Tests of departures from Hardy-Weinberg equilibrium indicated all 64 loci in 8 stocks were significantly deviated from Hardy-Weinberg equilibrium after Bonferroni correction and most of them have significant heterozygosity deficiency.All of 8 stocks showed higher genetic diversity, and genetic diversity of the stocks in DP was the highest, and that of PW was the lowest.F_ST and AMOVA analysis across all stocks and loci indicated that there was medium level of divergence among 8 stock.F_ST=0.126 (0.05<F_ST<0.15).The UPGMA clustering tree based on genetic distance (D_A) demonstrated that the stocks of PW, QT and DP clustered into one group; TP, XS and GT converged into another group, and GC and YH constituted a branch singularly.

Abstract:Oujiang color common carp (Cyprinus carpio var.color) has two kinds of scales, the soft scale and the hard scale.Nutritive components of these two types of scales were compared in this study.The results indicated that the moisture content of the soft scale (54.94%) was higher than that of the hard scale (46.67%),P<0.05.The dry weight of crude protein, crude ash and crude fat in the soft scales were 79.84%, 17.18% and 2.09%, respectively, whereas these measurements in the hard scales were 82.57%, 14.84% and 2.06%, respectively.There were significant differences (P<0.05) between the soft and hard scales except for the crude fat.In total, sixteen different kinds of amino acids were determined in the scales.The dry weight concentration of all amino acids in the soft scales was lower than that in the hard scales except for lysine.In addition, the content of essential amino acids in the hard scales was higher than that in the soft scales (P<0.05).Based on the results of the comparison, we concluded that the degree of hardness and softness of fish scales of the Oujiang color common carp could be influenced by the content of moisture, the proportion of crude protein and crude ash in the scales.

Abstract:Coilia nasus is a kind of mid-small-sized fish with resident and migration ecotypes.The anadromous population has long been recognized as very important commercial aquatic products in the lower reaches of the Yangtze River.To evaluate the fishery biological characteristics, we analyzed 458 specimens of Coilia nasus collected at Jingjiang section of the Yangtze River in fishing season, in May, 2012.The results showed that the spawning stock included 1-4 years old groups with 85.81% of age 2 to 3 years.The body length ranged from 14.2 to 38.9 cm with an average of (25.72±4.08)cm and the body weight varied from 9.2 to 208.4 g with an average of (69.59±33.73)g.Body length and body weight were fitted into the function W=0.0028L^3.0866(R²=0.915 3), The average fatness was only 0.38±0.08.Based on the von Bertalanffy growth equation:L_t=40.82[1-e^{-0.31(t+0.55)}],W_t=262.59[1-e^{-0.31(t+0.55)}]³，we calculated the asymptotic length of 40.82 cm and the asymptotic weight of 262.59 g.The age at inflection point of body weight growth curve was 2.99 years old when body weight was W_t=77.66 g.Compared with the study results in 1970s, the recruitment and young surplus populations of the spawning stock increased significantly in reproductive population.Low-age and miniaturization tendency was obviously accompanied with fatness decrease.However, the growth potential was still high on the basis of the growth equation.The results suggest that active measures such as reducing fishing intensity of the reproductive population and protecting the spawning grounds are imperative to maintain this precious fishery resources.

Abstract:Food poisoning incidents have occurred in China because of eating goby, which is a species of fish living with a common edible mudskipper (Boleophthalmus pectinirostris).In order to investigate the goby species and its toxicity in this study, the goby samples were collected from Xuwen (Zhanjiang, Guangdong province) where the poisoning accident occurred in 2007.Based on the morphological features, the fish was identified as Yongeichthys criniger, which was reported as a tetrodotoxin (TTX)-accumulated fish species in Japan, and Taiwan province of China.The amount of TTX in each tissue of Y.criniger and Takifugu fasciatus was measured using enzyme linked immunosorbent assay.The tissue with TTX content in per kilogram tissue in Y.criniger from high to low is liver (69.954 mg), ovary (9.510 mg), skin (8.937 mg), muscle (5.181 mg), and eye (3.321 mg).The amount of TTX in each tissue of Y.criniger is higher than that in same tissue of Takifugu fasciatus.This is the first report about the amount of TTX in Y.criniger from mainland in China, and the investigation is helpful to prevent people eating toxic Y.criniger.

Abstract:A constructed wetlands ecosystem was developed with intermittent operation combined with microvesicle aerators and water purification nets to circularly treat culture wastewater for the purpose of studying the effect of regulating-controlling water quality for Macrobrachium rosenbergii culture and the prawn growth characteristic.The FWS-SF wetlands ecosystem used in this study consisted of a free water surface flow (FWS) wetland and a subsurface flow (SF) wetland.The whole area of FWS-SF wetlands was 582.2 m², including three units: the slope unit, the macrophyte unit, and the reservoir unit.The experiment was conducted during a 117 day period with no water exchange and medicine use.Since the 31th day, the constructed wetlands ecosystem was intermittently operated at a hydraulic loading rate (HLR) of 1.03 m/d during the culture period, and significantly removed NO₃^--N, COD_Mn, TAN by 66.4%, 39.6% (P≤0.01), and 45.0% (P≤0.05) respectively, the removal percentage of NO₂^--N was 33.3% and keep in very low concentration (0.006±0.005 mg/L).The main aquatic chemical parameters of experimental ponds were all maintained within a suitable and safe range for prawn growth, and blue-green algae bloom was effectively inhibited.At the end of the experiment, because of blue-green algae toxic effect, average adult prawn size and yield of the control pond (8.70 g, 0.32 kg/m²) were smaller or lower than that in the experimental pond (9.51-10.72 g, 0.38-0.41 kg/m²).The study presented three groups of growth equations of the relationship between body weight and body length, body weight and culture days, body length and culture days，respectively, it can provide a scientific basis for designing the culture production plan, adjusting the production measures and estimating yield of Macrobrachium rosenbergii.This experiment shows that constructed wetlands ecosystem at intermittent operation and combined with pond simple facilities could effectively control water quality in prawn pond under the conditions of no water exchange and no medicine use and then ensured a good harvest.

Abstract:Rice-crab co-culture is an important agricultural industry in Chongming Island.During the past twenty years, because of the improvement of environmental quality and enhancement of bird conservation, the number of bird species and population increased significantly in Chongming Island.However, this increasing number of birds brings a certain trouble to rice-crab co-culture pond as many birds generally feed on crab and rice.Therefore the current study was firstly conducted to investigate the major species of bird trouble, and to identify the influence time and major trouble birds for two rice-crab co-culture models, furthermore, to evaluate the input and output of two ecological methods for bird prevention.The results showed that, (1) there were 13 major bird species in the rice-crab co-culture area, and the most common speices are egrets with six species found in our investigation.(2) the major trouble birds were egret species for crab culture ponds and the major trouble periods were winter and spring; the major trouble birds were egrets, sparrows and magpies for rice-crab co-culture ponds while sparrows and magpies were the main trouble for the rice crop during the periods of seeding, filling and maturation.(3) the method of nylon wire prevention was cheaper than the combination of nylon wire and anti-bird net; however, the combination method is suitable for rice-crab co-culture ponds.In conclusion, the combination method of nylon wire and anti-bird net, together with visual bird prevention such as scarecrow, had the significant effects in the control of bird trouble for rice-crab co-culture ponds, which will eventually lead to the good results of bird prevention, economic benefit and ecological effect for both the rice-crab co-culture and bird protection in Chongming Island.

Abstract:In this paper, the artificial breeding technology of Ulva prolifera on a large scale was studied.Firstly, the effects of temperature and thallus density on the releasing of spores from blades of U.prolifera, and effects of temperature and light intensity on attaching and germination of spores from U.prolifera blades were studied.The results indicated that the quantity of spores releasing from blades of U.prolifera reached the highest when temperature was at 25℃and thallus density was 0.8 g/L; the optimum temperature and light intensity for attaching and germinating of spores released from blades of U.prolifera were 20℃ and sunny days[light intensity>300 μmol/(m²·s)]; and when seedling length reached up to 1-3 cm, it was good for seedlings on nets moving and cultivateing at coast.From Dec 10, 2013 to Jan 26, 2014, the artificial breeding experiment in U.prolifera on a large scale was carried out in Yizhen Seaweed Technology Co., Ltd., Hebosuo Village, Xiangshan Harbor, Fenghua County, Zhejiang Province, China.Basing on the key parameters of artificial breeding, and the technology of artificial breeding in U.prolifera on a large scale was initially established.About 17.82×10¹⁰ spores were released from 6.6 kg fresh thallus, and the average spores releasing rate was about 2.7×10⁷ spores/g.Totle about 2 000 nets (16 m length×1.0 m width) were used for breeding, and average spores attaching rate was about 8.64×10⁷ spores/net.After breeding for 7 days, the germinating rate of spores attaching on nets reached the peak, and the average seedlings density on rope was about 20 seedlings/cm, and the longest of seedlings was about 3 cm.Those parameters met the requests for seedlings cultivating at coast.Whole breeding took 45 days.It would lay a foundation for establishing the artificial breeding technology of U.prolifera on a large scale.

Abstract:Three uptake experiments were performed under laboratory conditions: (1)Phosphate uptake kinetics of macroalga, Sargassum horneri, between 5-25℃;(2)Effect of N:P ratio on the uptake of N and P by S.horneri; (3)Effect of NH₄⁺-N/NO₃^--N ratio on the uptake of N and P by S.horneri.The results were: (1)The maximum absorption rate(V_max)rises with temperature variation between 5-20℃,and reaches the max at 20℃; The half saturated absorption constant (K_m) decreases with temperature variation between 5-20℃, and reaches the min at 20℃; (2)when the N concentration was constant, the uptake rate of N and P decreases with the N:P ratio variation between 16:1 to 256:1; While the P concentration was constant, the uptake rate of N rises, and P decreases with the variation of N:P ratio.(3)when phosphate is adequate, the uptake rate of NO₃^--N has a negative relation with NH₄⁺-N/NO₃^--N, while NH₄⁺-N and P have a positive relation with NH₄⁺-N/NO₃^--N variation between 1:1-8:1, and a negative relation with that above 16:1.(4)The TN and TP in S.horneri are 5.70% and 0.18%, respectively.

Abstract:A new method based on molecular mass for rapid determination of inorganic arsenic in algae by electrospray ionization mass spectrometry was developed. Several conditions affecting accuracy and sensitivity such as extraction method, pH of solvent, reductant, chelating agent, extractant and instrument parameters were studied. Under the optimum conditions, the calibration curve of As(Ⅲ) was linear in the range of 0-151.4 ng/mL, the calibration curve of As(Ⅴ) was linear in the range of 0-175.0 ng/mL, and the correlation coefficients were all above 0.99. The limit of detection(S/N > 3)was 0.024 mg/kg and the limit of quantitation (S/N > 10)was 0.048 mg/kg. The recoveries at different spiked concentration levels ranged from 81.0% to 95.6% with relative standard deviations(2.52%-7.54%). This method is simple, of high sensitivity and good reproducibility, without interference of organic arsenic. It can be applied to analyze inorganic arsenic in algae and can provide technological support for food safety management.

Abstract:In order to study the hepatoprotective effects of Chinese herbal medicine Lycium barbarum poly-saccharide(LBP)against carbon tetrachloride-induced hepatocyte injury in Cyprinus carpio var.jian.Different concentrations of LBP(0.1 mg/mL, 0.2 mg/mL, 0.4 mg/mL) were added to the carp primary hepatocytes before(pre-treatment),after(post-treatment)and both before and after(pre-and post-treatment)incubation of the hepatocytes with CCl₄.After 12 h, the cell and supernatant were collected, and then the levels of glutamatepyruvate transaminase (GPT),glutamate oxalate transaminase(GOT), lactate dehydrogenase(LDH),malondialdehyde(MDA), superoxide dismutase(SOD), cell viability,tumor necrosis factor-α(TNF-α),Interleukin-1β(IL-1β),immunoglobulin M(IgM)and cytochrome p450 2E1(CYP2E1)were measured.The results showed that CCl₄ at 8 mmol/L in the culture medium significantly elevated the levels of GPT, GOT, LDH, MDA, TNF-α, IL-1β, IgM and CYP2E1, and significantly reduced levels of SOD and cell viability; however, treatment with LBP attenuated the adverse changes of these biochemical indexes, especially in pre-treatment and pre-and post-treatment; the changed levels of GPT, GOT, LDH, MDA,TNF-α, IL-1β, IgM and CYP2E1and the elevated levels of SOD and cell viability were significantly inhibited in a dose-dependent manner, while the post-treatment of hepatocytes with LBP only significantly reduced the levels of LDH,TNF-α and CYP2E1.Based on the results, it is indicated that LBP may have the hepatoprotective effects against carbon tetrachloride-induced hepatocyte injury in Cyprinus carpio var.jian and may be used as a hepatoprotective agent in fish liver diseases.

Abstract:This study was conducted to investigate the effects of chitosan-oligosaccharides on the growth performance, nonspecific immunity and antioxidant parameters of FFRC Strain Common Carp (Cyprinus carpio).The fish (mean initial weight: 33.90 ± 0.11 g) were randomly divided into 4 groups with 5 replicates per group and 15 fish per replicate.The fish were fed with either basal diet (control group) or basal diet supplemented 25, 50 and 100 mg/kg chitosan-oligosaccharides for 35 d, respectively.The results showed that dietary supplementation of chitosan-oligosaccharides did not significantly affect the growth performance and muscle composition of fish compared with the control group (P>0.05).As expected, dietary chitosan-oligosaccharide supplementation significantly enhanced the activities of plasma alkaline phosphatase (AKP).The similar effects were also observed on the concentrations of plasma complement 3 (C3) and complement 4 (C4) as well as the content of total iron binding capacity (TIBC) in plasma (P>0.05).In addition, dietary chitosan-oligosaccharide supplementation at 25 mg/kg also significantly enhanced the content of nitric oxide (NO) in spleen.The activity of myeloperoxidase (MPO) in spleen was promoted in fish fed chitosan-oligosaccharide at 50 (P<0.05) and 100 mg/kg (P<0.01).Dietary 50 mg/kg chitosan-oligosaccharide supplementation significantly increased superoxide dismutase (SOD) level and decreased the maleic dialdehyde (MDA) content in plasma (P<0.05).Based on the results above, it was indicated that chitosan-oligosaccharides could effectively improve nonspecific immunity and antioxidant parameters of FFRC Strain Common Carp (Cyprinus carpio) and the optimum level of 50 mg/kg exerted the best effects on FFRC Strain Common Carp in the present study.

Abstract:The paper dealt with the proximate biochemical composition and fatty acid composition of Chinese mitten crab Eriocheir sinensis acclimated to Tibetan plateau during its overwintering by virtue of biochemical analysis.The results are as follows: (1) Hepatopancreas index (HSI) decreases significantly after overwintering, from 11.72% to 9.96%; (2) After overwintering, relative content of total lipid and protein in hepatopancreas and muscle decreases significantly, and relative content of water in hepatopancreas goes up but down in muscle significantly; Amount of saccharides showed no significant difference in both hepatopancreas and muscle during overwintering; (3) Relative content of free fatty acids and phospholipid in total lipids of hepatopancreas and muscle reduces significantly after overwintering; Relative contents of triglyceride in hepatopancreas increases but lowers in muscle significantly; (4) Among fatty acids, primary saturated fatty acids (SFA) C16:0,C16:1n7 and primary monounsaturated fatty acids (MUFA) C18:1n9 and C18:2n6 were consumed above 10% for energy metabolism during overwintering, nearly in line with SFA and MUFA burned in muscle.It was worth noting that C20:5n3(EPA) and C22:6n3(DHA)of high level in polyunsaturated fatty acid (PUFA) (23.47% and 12.38% of total lipid in muscle respectively) were also consumed, but its relative content increased to some extent after overwintering; (5) A large amount of protein in muscle and lipids in hepatopancreas are simultaneously mobilized to fuel for energy metabolism during overwintering, implying that E.sinensis cultured in Tibetan plateau is subjected to stress of both coldness and starvation.It is suggested that prior to overwintering,Chinese mitten crab acclimated to Tibetan plateau be enriched with relevant lipids and protein to improve the survival rate during its overwintering.

Abstract:A serine protease from Euphausia superba was purified by a series of procedures, including ammonium sulfate precipitation, column chromatographies on DEAE-Sepharose and Phenyl-Sepharose.The purification multiple of the protease was 5.44 times, and the yield of the protease was 26%, with specific activity of 38.3 U/mg.As shown in the result of SDS-PAGE electrophoresis, the molecular weight of this protease is 28 ku.The optimum temperature of protease was 37℃ and the most suitable pH was 7.5.Mg²⁺, Ca²⁺and Mn²⁺were activated to protease from Euphausia superba.However, Zn²⁺, Cu²⁺and Fe³⁺ were inhibited to the enzyme activity, and the inhibition ability of Cu²⁺ was the strongest.The enzyme kinetics experiments were performed by using BApNA as substrate.The results showed that the K_m value was 0.073 mmol/L, V_max value was 1.44×10^-2 mmol/L·s，k_cat value was 0.6 S^-1 and k_cat/K_m value was 8.22×10³.PMSF was a protease inhibitor, and its mechanism of action was irreversible inhibition.

Abstract:Nannochloropsis sp.is commonly used as weaning feed in aquaculture, the protein content of which plays an important role in the growth and development of seedlings of aquatic animals.In this paper, three kinds of nutrients, N, P and Fe, were tested by orthogonal design methods at three levels on Nannochloropsis sp.The biomass and protein content were determined at the end of experiment.Results showed that both biomass and protein content of Nannochloropsis sp.were influenced by the levels of N, P and Fe; among the range of nutrient concentrations of this paper, P had the greatest impact on the biomass while Fe had the greatest impact on the protein content; when N, P, Fe concentrations were 24.6, 1.1 and 0.2 mg/L respectively, both the biomass yield and protein content were the highest.

Abstract:An artificial floating bed experimental project in which reeds served as the floating bed plants was carried out on the adjacent water of Qingcaosha Reservoir in the Yangtze River Estuary to study its growing state and nutrient uptake ability.The results showed that the average density of reeds increased gradually during the experiment with the lowest value of(25.6±2.5)ind/m² in May and highest(100.7±15.3)ind/m² in July, and the difference between months was significant (P<0.05).The plant height increased from(2.6±1.4)cm in May to(55±15.5)cm in July with significant difference between months (P<0.05).The average density of reeds was highly correlated with the plant height (R=0.904).The fresh weight of reeds per unit area was(0.212±0.045) kg/m², the dry weight of reeds per unit area was (0.063±0.013) kg/m², the TN concentration of reeds was (1.33±0.03) mg/g, the TP concentration of reeds was (0.27±0.01) mg/g.TN fixed amount per square meter was (83.67±17.01) mg/m², TP fixed amount per square meter was (17.33±4.16) mg/m².

Abstract:In order to provided building sites of biological collocation and landscape effect for plankton, large algae, fish and others' optimal growth model, we analysed the building model of aquatic animals in filtration and temperature control system through the establishment of aquarium.According to the aquarium market research, the animal and plant configuration in system is as follows.The clean shrimps and coral is 5:1, Rhodophyta, Chlorophyta and Phaeophyta is 7:5:3.The water quality monitoring result showed that the water hardness, TN and TP were maintains at 5 159 mg/L, 28.38 μmol/L and 6.09 μmol/L during stable phase respectively .The water quality was reached to the second class of the water standard, which is suitable for mariculture.It is the construction of the evaluation index system of ecological system stability that to evaluate the system's running efficacy.While the result shows that R=8.54, the system is between intermediate and high stability, and biodiversity in the ecological system is the determinant factor.A stable mariculture system is time-saving and cost-saving，providing places for animal and plant breeding research and achiveing the multiple effects, such as being scientific, economic, stable, beautiful, etc.The construction of the system model also provides theoretical basis for the "economy-ecological-humanities" life philosophy.

Abstract:To clarify the species composition and diversity of fish larvae and juveniles in the north of Hangzhou Bay, monthly collections were held by a larva net (1.3 m mouth-diameter, 0.5 mm mesh-aperture) from January to December, 2013.There are 10 sample stations in this study.A total of 81 eggs belonging to 6 species from 4 families and a total of 143,782 individuals of more than 69 species from 23 families were collected.The number of estuarine species and marine species was 34 and 24 respectively, greater than that of diadromous species (4 species) and fresh water species(7 species).Collichthys lucidus is in the majority among eggs.The most dominant species of them was Tridentiger barbatus, accounting for 62.88% of this total abundance, followed by C.lucidus for 13.02%, Coilia mystus for 9.22%, Acanthogobius flavimanus for 2.56% and Acanthogobius ommaturus for 2.32%.Fish larvae in preflexion stage accounted for 89.12% of total abundance and were most in June (85.31%).Species number and density in spring and summer were significantly higher than those in autumn and winter.The density in June had a sharp increase (13.50 ind/m³) and the species number in July (species number=18) was the greatest of all months.The Margalef index changed greatly overall and sharply between months.The Shannon-Wiener index and Pielou evenness index had smaller changes between months.

Abstract:Jingjiang section of the Yangtze River, which is an important area for fishery resource conservation and reproduction of anchovy, is located at the connected region of lower reaches and estuary of Yangtze River.In 2002, Ministry of Agriculture of the People's Republic of China decided to carry out fishing ban in Yangtze River.Fishing boats would not be allowed to fish Coilia nasus in Yangtze River unless they have special fishing license during the period of spring closed fishing season.The fishing season of anchovy in Jiangsu section is approximately divided by the the Jiangyin Yangtze River Highway Bridge.We monitored daily variation in C.nasus catches based on log data of anchovy from 16 fishing boats in Jingjiang section of the Yangtze River from February to May in 2008, 2009, 2012 and 2013, and analyzed temporal and spatial variations in C.nasus catch as they relate to environmental factors.Results showed that the daily catch number (N_B) and daily catches weight per boat (W_B) ranged from 0 to 351 ind./d and from 0 to 39.5 kg/d, with an average of (21±38) ind./d and (2.0±4.1) kg/d, respectively.Meanwhile, total annual catch (N_t)and total annual catch (W_t) per boat ranged from 130 to 3952 ind.and from 10.9 to 435.6 kg, with a mean of (890±929) ind.and (92.3±91.1) kg in fishing season, respectively.N_B and N_t showed the similar annual variation trend, the maximal peak N_B and N_t occured in 2013, and other years' N_B and N_t maintained at relatively low level.However, annual variation trend of catch weight was different from that of catch number.W_B and W_t continued to decline from 2008 to 2012, and then a significant rise was found in 2013.As fishing season progressed, the N_B and W_B increased markedly.N_B and W_B were very low in February and March, then increased to (23.0±31.3) ind./d and (2.4±3.5) kg/d in April, and reached a maximum in May, Which were (78.0±81.0) ind./d and (7.7±9.1) kg/d, respectively.The ANOVA analysis showed that N_B and W_B in west water area of Jiangyin Yangtze River Bridge were significantly higher than those in east water area (P<0.001).N_B and W_B in west water area were 2.5 and 2.7 times those in east water area.Highly significant correlations were obtained between W_B and daily water temperature and between W_B and the maximum daily water level (P<0.05).The results suggested that the rise of water temperature off Yangtze River Estuary may be an important environmental factor, which can induce C.nasus to start migration.Further, the peak W_B appeared near the highest water level, probably because of the fixed net filtering more river water.

Abstract:The samples derived from the Chinese vessels were collected from 7 locations of central Pacific Ocean waters (16°S-8°N;160°W-155°E)from September 2011 to January 2012.By using 585 bp fragments of mtDNA control region, we analyzed the sequence variations and genetic structures of 101 samples collected from 7 locations.In total, 23 variable sites were acquired, and 80 haplotypes were identified.Analysis of mtDNA D-Loop gene sequences from 7 localities revealed that the mean haplotypic diversity and nucleotide diversity was 0.994±0.002 and 0.00892±0.00038, respectively.The AMOVA tests revealed that 98.18% of the genetic variation occurred within populations.F_st analysis suggested that no significant genetic differentiations were found within the 7 localities.Neutrality test and the mismatch distribution indicated a recent population expansion that occurred about 3 350 000-5 440 000 years ago, suggesting a frequency genetic exchange and a poor genetic structure.A single population and a low genetic diversity call for a responsible and effective management to ensure the sustainable development of yellowfin tuna.

Abstract:As one of the most important fishery areas in the world, Western and Central Pacific Ocean is one of the most productive zones for tuna fishery.The 22 countries and regions have vast Exclusive Economic Zones and limited land resources.The characteristics of these islands make fishery the only way for their economic development.Western and Central Pacific Fisheries Commission, together with Pacific Islands Forum Fisheries Agency and the Secretariat of Pacific Community, take compatible measures to reduce fishing capacity and ensure sustainable development of the fishery resources in this area.However, the conservation and management objectives have encountered such challenges as overcapacity, lack of fishery data, IUU fishing, low enforcement efficiency of the measures, as well as the interference of political factors.The study on tuna fishery management in Western and Central Pacific Ocean may provide an understanding for the development tendency of policies and measures in this important fishing area, and may serve as references for Chinese policy makers in their decision-making process of distant water fishery polices.

Abstract:We carried out the research of the testing parameters of biofan in order to formulate the practical and feasible industry standard for it.It is difficult to quantitatively analyze the performance of biofan, because the water in culture pond constantly changes with various factors such as water temperature, air pressure, photosynthesis, water salinity and farmed species, etc.To study the testing parameters of biofan, we utilized the 6.3m diameter laboratory standard tank as a testing platform, and conducted the experiments at 20℃ water temperature, 101.325 kPa air pressure, and 0 mg/L initial concentration of dissolved oxygen, by reference to the standard testing procedures described in the "SC/T 6009 Test methods of oxygen-enriched capacity for aerator".The comparative experiment was done for three types of biofan in clean water.The experiment results show that it is still feasible to judge the basic parameters such as net buoyancy rate and insulation resistivity by using the criteria of aerator; and the other parametes such as no-load noise, oxygen transfer capacity and power efficiency changed greatly; the parameter of the action depth of biofan should be added to be adapted to the qualification testing of biofan.