Abstract:To learn the role of miR-202 in the zebrafish embryonic development, miR-202 expression was detected using qRT-PCR and WISH. The results indicated that miR-202 is a maternal molecule and expressed continuously during the zebrafish embryonic development, especially at the early stages. Knockdown of miR-202 was performed by microinjecting the locked nucleic acid modified antisense oligo of miR-202. The results showed that antisense oligo of miR-202 decreased miR-202 level significantly, accompanied with an early termination of the zebrafish embryonic development at around 4 hpf. And miR-202 inhibition induced early termination could be partly rescued by co-injection of pre-miR-202, indicating that miR-202 is required for the early zebrafish embryonic development. The present study for the first time unveils the essential role of miR-202 for the zebrafish embryonic development.

Abstract:Single nucleotide polymorphism(SNP) markers coupled with the next-generation sequencing technology are powerful tools for studying population genetics, as well as for species delimitation. The popular ways of obtaining SNP data include RNA sequencing and restriction site associated DNA(RAD) sequencing. However, both methods have limitations. For example, RNA sequencing requires fresh tissue samples, whereas RAD sequencing targets anonymous loci usually not transferable across species. In comparison with these methods, target gene capture could be used to enrich homologous fragments across divergent species and even from degraded DNA. We showed that by targeting a set of universal single-copy nuclear gene markers of vertebrates, we could retrieve thousands of SNPs from the Japanese grenadier anchovy(Coilia nasus) sampled from three locations:coastal region close to the estuary of the Yangtze River, the mainstream of the river and Lake Dongting, a lake connected to the middle reaches of the Yangtze River. We analyzed hundreds of representative SNPs from the data using STRUCTURE and Bayes factor delimitation(^*with genomic data; BFD^*), a new Bayesian species delimitation tool. We found that the fish from Lake Dongting are genetically different from the fish of other sample locations. We also observed marginal difference between fish collected from the coastal region and the mainstream of the Yangtze River(Bayes factor=11.3). Our study demonstrated that gene capture could be used to generate SNP data for species delimitation applying new analytic tools such as BFD^*.

Abstract:To explore the role of miR-33 in the regulation of fat metabolism by sterol regulatory element binding protein 1(SREBP-1), the dual-luciferase reporter assay vector containing SREBP-1 gene 3'-untranslated region of Ctenopharyngodon idella has been constructed. The 3'-UTR of SREBP-1 with miR-33 combining site was first amplified(with the length of 379 bp) and transfected into competent cells(DH5α) after being recombined with dual-luciferase reporter assay vector(pmirGLO). Screening and identifying with XbaI and SacI to digest the recombinant vector were then conducted. Finally, the relationship between miR-33 and the 3'-UTR of SREBP-1 was analysed by the co-transfection of the recombinant vector and miR-33 mimics into L8824 cells. The electrophoretogram of PCR products, the restriction map of recombinant vector, and the result of gene sequencing comfirmed that the dual-luciferase reporter assay vector containing 3'-UTR of SREBP-1 was successfully constructed. In addition, the activity of luciferase expressed by transfected L8824 cells was detected and the expression level of the control was significantly higher than that of the co-transfected group including the recombinant vector and miRNA-33 mimics. The results suggested SREBP-1 is the target gene of miR-33. By binding to the 3'-UTR region of SREBP-1, miR-33 plays an important role in the regulation of post-transcription of SREBP-1.

Abstract:LEAP2(Liver expressed antimicrobial peptide-2) antibacterial peptide is a kind of small molecular peptide expressed mainly in the liver of animals, and they play important roles in the immune systems of animals. The primary structure of LEAP2 from channel catfish(Ictalurus punctatus) is composed of signal peptide and prepeptide which is composed of 66 amino acid residues. The 41 residues near carboxyl terminal of the prepeptide form mature peptide region(mLEAP2), which is responsible for biological activity of the LEAP2 antibacterial peptide. The present study focused on the mLEAP2 for channel catfish. Recombinant DNA expression of the mLEAP2 in Pichia pastoris was realized by constructing P. pastoris expression system. The optimized expression conditions were as follows:29℃, pH 6, 250 r/min, 0.5% methanol and 120 h. Tricine-SDS-PAGE analysis indicated that the expressed product was highly purified by immobilized metal affinity chromatography(IMAC). The concentration of the purified product was 0.22 mg/mL, thus the expression yield of recombinant protein was calculated to be about 2.2 mg/L. Structure of the purified product was further identified by MALDI-TOF/TOF analysis, and the result demonstrated that the purified product was the recombinant mLEAP2(rmLEAP2) expected. In addition, antibacterial assay showed that the fermentation supernatant containing the rmLEAP2 had bacteriostatic activity against Bacillus subtilis.

Abstract:Six populations of Sinonovacula constricta came from Yueqing Bay, Zhejiang and other five populations from Jiangsu and Fujian Provinces. Based on the morphologic data, the population from Fujian Zhuta is more similar to five wild populations of Yueqing Bay; The mean of discrimination accuracy of 11 populations is 82.4%, the eigenvector-loading values from Front-end of dorsal to Front-end of dorsal, from Front-end of dorsal to Back-end of dorsal, and from Beak to Anterior of body are higher than other parameters, and they all are the important to distinguish populations. SRAP analysis on 11 populations shows the genetic diversities of wild populations from Yueqing Bay are relatively high with mean Shannon's index 0.481 4, and the mean Shannon's index of other populations is 0.402 8; All six populations from Yueqing Bay gathered into one branch. Together, the morphology and SRAP both showed that the wild populations of Yueqing Bay were more highly similar.

Abstract:In order to explore the rules of releasing monospores of Pyropia, we used the wild-type strain(PC-WT) and its mutant strain(PC-Y1) in Pyropia chauhanii as materials, to study the rules of releasing monospores on the blades discs from different ages and different parts. The results showed that the discs from different ages or different parts of PC-WT blades, the time and number of releasing monospores had a certain difference during two weeks of culture. Discs from the apical, middle and basal parts of the 40-day-old blades did not display sexual cells, the daily number of releasing monospores showed a trend of increasing first and then decreased, and the order of total number after culture of 12 days was middle > apical > basal. The discs from the apical and middle parts of the 45-day-old blades had sexual cells already, and the time to release monospores became earlier as compared with the 40-day-old blades, but the total number of monospores declined, the collapse speed of discs was faster, and the order of total monospore number was middle > apical > basal. The discs from the apical and middle parts of the 50-day-old blades collapsed completely on the 6^th days and 10^th days of culture, respectively, and it was found that the discs almost matured, the total number of monospores was less, while the discs from basal part did not mature, and the total number of monospores was the greatest. The discs from the apical, middle and basal parts of PC-Y1 blades grew well with edge integrity, and did not release monospores. The discs from the 40-day-old blades did not present sexual cells, and its vegetative cells were bright-red and tight. The discs from 45-day-old and 50-day-old blades presented sexual cells. These results indicated that PC-WT is a strain which can release monospore, the monospore releasing time order was apical > middle > basal; With the increase of the blades age, the time of releasing monospores became earlier, but the total number of monospores decreased; The PC-Y1 is a strain which released no monospore at different ages or from different parts of the blades, indicating that its genes linked to the formation and release of monospore had probably mutated.

Abstract:In order to understand the the nutritional requirement of juvenile tawny puffer(Takifugu flavidus) during the bait conversion period, the growth, body lipid content and its fatty acid composition of tawny puffer juvenile before, during, and after the domestication were detected and analyzed by biochemical analysis methods. The results show that the phenomenon of body weight compensatory growth of tawny puffer juvenile has been found after the domestication; the highest condition factor of juvenile was found before the domestication(10.02), the lowest condition factor was found during the domestication(5.43), and it increased significantly after the domestication(6.00). The dry matter contents of tawny puffer juvenile increased significantly after the domestication. 8 saturated fatty acids(SFA), 7 mono-unsaturated fatty acids(MUFA), and 12 poly-unsaturated fatty acids(PUFA) were found in the dry sample before, during, and after the domestication. From the percent content, during the bait conversion period, the C16:0 content of tawny puffer juvenile was the highest and stable(21.26%-23.81%), the C18:0 content decreased significantly, and the C16:1 and C18:1n9c contents increased significantly; the C22:6n3(DHA) content was rich(11.95%-13.05%), it decreased faintly during the bait conversion period;the C20:5n3(EPA) percent content of juvenile decreased faintly during the domestication, and increased faintly after the domestication; the C22:5n3(DPA) percent content decreased significantly during the bait conversion period. During the bait conversion period of tawny puffer juvenile, the SFA was relatively stable(38.13%-42.52%), the MUFA increased significantly, however, PUFA decreased significantly, especially∑n3PUFA. And more notably, the C18:2n6c percent content of the compound feed was particularly high(21.29%), however, the C18:2n6c content of juvenile fed with compound feed was very low(2.47%);On the contrary, the C16:1 percent content of the compound feed was particularly low(3.87%), however, the C16:1 content of juvenile fed with compound feed was very high(9.25%). Therefore, tawny puffer juvenile had a higher demand for n3PUFA(especially DHA and EPA), but didn't need too much C18:2n6c, and part of the C16:1 in juvenile body was from transformation of other nutrients. In order to improve the survival rate of tawny puffer juvenile during the bait conversion period, it is suggested that:1) Before the domestication of tawny puffer juvenile, enhancing live bait, especially seawater copepods enriched with n3PUFA;2)Increasing the additive amount of DHA and EPA, reducing the proportion of C18:2n6c, and increasing the proportion of C16:1, in the compound feed of tawny puffer juvenile during the bait conversion period.

Abstract:To investigate heterosis and combining ability of the diallel crosses of different Apostichopus japonicas populations which were from Changdao(C), Dalian(D), Weihai(W) and Jiaonan(J), the experiment established 16 groups of 4×4 diallel crosses of different Apostichopus japonicas populations. The larval survival growth performance of 30 day(d), 60 d, 80 d and 105 d were obtained, and the heterosis, the general combining ability and the specific combining ability were compared between the different groups. The results showed that:The body length was different in different groups, and there was no significance between hybrid and selfing groups of 30 d, 60 d and 80 d. The body length of the hybrid groups which were groups of D(♀)×J(♂)(DJ), WD, JD and JC of 105 d was significantly greater than the combinations which were groups of CC, WW and JJ. The heterosis was different in different hybrid groups and different stages. The groups of CD, JC and JD were always positive, and the group of CW was always negative. The number of groups which were positive increased with growth of A. japonicas, and the groups of JC of 105 d was 9.69% and highest. The general combining ability of D(♀), J(♀) and D(♂) was higher than others. The special combining ability of groups of JD was higher on 30 d and 60 d, the groups of CD, DJ, JC and JD were higher than other groups on 80 d and 105 d. It can be concluded that the hybrid combinations of C(♀)×D(♂), D(♀)×J(♂), J(♀)×C(♂) and J(♀)×D(♂) of Apostichopus japonicas have better growth performance and higher special combining ability by comprehensive consideration.

Abstract:To learn the carbon metabolism of microbial communities of moving bed biofilm reactor which was adjusted to different process in recirculating aquaculture systems, and find out if microorganism had a better nitrification in moving bed biofilm reactor under the condition of energy conservation. Experiments changed the moving bed biofilm reactor to different process which were O²、A/O and O/A, respectively.Then, using Biolog-ECO method to analyse the characteristics of microorganism on the carbon source metabolism of moving bed biofilm reactor. The results showed that, the second section of O² process was the best of AWCD of microbial communities cultured in different process, then was the first section of A/O process, and the first section of O/A process was the worst.The utilization degree of carbon sources of microbial communities in different process show preference to amino acids and amines, the second section of O² process and the first section of A/O process were higher than the other process.The first section of O/A process was the highest in micro-organism diversity indices, then were the second section of O² process and the second section of O/A process, and the first section of O² process was the lowest.The PCA(principal component analysis) showed that contribution of PC1 of the micro-organisms in different process was 32.89%, PC2 was 25.91%, and there were 16 types of substrates in PC1 over 0.5 of load, and 14 in PC2.L-Asparagine and L-Arginine of amino acids, N-Acetyl-D-Glucosamine of carbohydrates, Tween 40 and Tween 80 of polymers, 4-Hydroxy Benzoic Acid of phenolic acids and Phenylethylamine of amines were better utilized by micro-organisms.γ-Hydroxybutyric Acid of carboxylic acids, D, L-α-Glycerol Phosphate of carbohydrates and 2-Hydroxy Benzoic Acid of phenolic acids were utilized worse.This experiment through changing the work conditions of moving bed biofilm reactor to study its carbon metabolism of microbial communities, which can provide a basis for further study of recirculating aquaculture system.

Abstract:Planktonic algae were investigated and researched monthly from January 2014 to December 2015 in Qingcaosha Reservoir, an important water source in Shanghai. There were 25 dominant species in 2014, and only 12 dominant species in 2015. Microcystis incerta, Pseudoanabaena sp., Cyclotella sp., Ankistrodesmus falcatus var. mirabilis and Klebsormidium scopulinum were common dominant species arising in two years. Compared with the data of 2014, the dominant species were substantially reduced in 2015, and the seasonal variation of dominant species was less obvious than in 2014. As a whole, the dominant species were more in summer and autumn than in winter and spring. The majority of dominant species groups was Cyanophyta and Chlorophyta. Dominant species groups showed the characteristics of more Cyanophyta in summer, autumn and more Chlorophyta in spring, summer. Algae of Bacillariophyta and Xanthophyta became dominant species more likely in spring and summer. Redundancy Analysis showed that water temperature, dissolved oxygen, total nitrogen, total phosphorus were the main environmental variables affecting most dominant species density. As for Microcystis incerta, the important dominant species, its density was positively related with water temperature. As for Tribonema sp. and Cyclotella sp., their density had negative correlation with water temperature.

Abstract:A total of 49 surface sediment samples from Southern Hainan Island were analyzed for heavy metals and grain size in order to identify their possible sources and assess their potential ecological risk. It showed that the surface sediments consist mainly of sand and silt and with scarce gravel and clay. The mean concentrations of the selected heavy metals were relatively low from the southern Hainan Island and the highest reached 38.98 mg/kg of Zn. Except for As, the other elements(Zn, Cu, Cd, Pb, Cr and Hg) exhibit significant positive correlations with each other and the contents of silt and clay. The assessment result of ecological risk revealed the southern Hainan Island possessed light potential ecological risks with the mean RI value of 14.55. The order of ecological risks for the selected metals is As > Hg > Cd > Pb > Cu > Cr > Zn.

Abstract:The pollution baseline values for different elements in the Changjiang Esturary and its adjacent areas were measured by investigation data obtained in 2000, 2006 and 2013, of which the abnormal data were first excluded and then normal distribution test was carried out. Trends of pollution baseline values from 2000, 2006 and 2013 were discussed, which showed that the pollution baseline values of phosphate increased while Cu, Cd and As decreased obviously. The results showed that the concentrations and fluctuation degree of parameters were different, and as a whole, the spatial distribution of different elements shows higher concentration in estuarine area, and the concentration decreases with the distance from the estuary. Factor analysis results show that the pollution source of nutrient is changing obviously, and the DIN contains two major pollutant sources recently. The source of metal is simple and unique, and the transformation of different metal elements in seawater is different.

Abstract:To clarify the annual changes of fish larvae and juveniles resource, monthly collections were held by a larva net in the north of Hangzhou Bay from June in 2014 to May in 2015. There were 10 sampling stations in this study. A total of 96 118 individuals were caught which belonged to 23 families and 55 species.The average density was 0.79ind./m³. 46 common species occurred in both years, while the abundance, species richness and average density were lower in 2014-2015. Tridentiger barbatus, Collichthys lucidus and Coilia mystus predominated in both two years. Development stage showed a similar tendency and pre-flexion larvae were dominant in 2 years. The density was significantly different(P<0.05) among stations and not significantly different(P>0.05) among months. The number of Margalef richness index(D) demonstrated distinct seasonal variations:they were higher in summer and lower in winter.The results of Margalef richness index(D), Shannon-Wiener diversity index(H') and Pielou evenness index(J') in summer of this research were higher than in 2013.

Abstract:Skipjack tuna, Katsuwonus pelamis, is an important economic species in the central-west Pacific Ocean, and this species is vulnerable to the change of marine environment. In this paper, according to the abundance index(unit net yield, CPUE) of skipjack tuna collected from the tuna large purse seine fisheries in the central-west Pacific Ocean from 1995 to 2010, combined with the El Nino/La Nina events(expressed by NINO 3.4 index), the influence of El Nino/La Nina on the abundance index of skipjack was studied with the time series analysis. The results showed that the yearly and seasonal abundance index of skipjack varied greatly in 16 years, in which the maximum monthly CPUE appeared in February 1995 with 30.37 t/net, and the minimum occurred in October 1997 with 5.35 t/net. The effect of Nino 3.4 index on monthly CPUE lagged 0-2 months in time, but the synchronization(lag 0 month) had the highest correlation. The Nino 3.4 index and monthly CPUE had significant negative correlation. According to the level of 16 years abundance index of skipjack and Nino 3.4 index, we chose four months(August to February of the next year) of CPUE values as studying object, and divided 16 years into two periods:1) First period was before 2000, this time period had a strong El Nino(SSTA>1.0℃), strong La Nina(SSTA<1.0℃) and normal years(0.5℃ < SSTA < 0.5℃). When the strong El Nino year occurred(1997), the abundance index of skipjack was at a lower level with monthly CPUE of 7.05 t/net. When a strong La Nina(1998) occurs, the abundance index was high with monthly CPUE of 19.61 t/net. 2) The second period was after 2000, which contains weak El Nino(0.5℃ < SSTA < 1.0℃), weak La Nina(-1.0℃ < SSTA < -0.5℃) and normal years(-0.5℃ < SSTA < 0.5℃). In the years of weak El Nino, the abundance index of skipjack(such as, the average CPUEs in 2002 and 2006 are 15.27 t/net and 16.81 t/net respectively) fluctuated around the mean CPUE value(15.73 t/net), but still lower than that in the La Nina year's(19.90 t/net). Both the CPUEs during weak El Nino and weak La Nina were higher than that in the normal year(14.16 t/net). In conclusion, the temporal and spatial abundance index of skipjack varied with both the changes of marine environment and the primary productivity caused by the El Nino/La Nina phenomenon.

Abstract:Resources of Macrobrachium nipponense and Exopalaemon modestus are extremely abundant, which occupies a very important position in fisheries of the Dianshan Lake; These species are also the main source of income for local fishermen. This paper focused on studying temporal and spatial changes in resources of the freshwater shrimps, M. nipponense and E. modestus, according to the survey data during the period from August 2010 to August 2011 in the Dianshan Lake. The results showed that the range of carapace length of M. nipponense was 7.05-47.07 mm, averaged(22.192±1.650) mm, dominant carapace length was 15.5-30.5 mm, accounting for 82.98% of the whole carapace length; the range of carapace length of E. modestus was 9.10-38.7 mm, averaged(21.221±1.598) mm, dominant carapace length was 15.5-25.5 mm, accounting for 80.49% of the whole carapace length; Resource density for M. nipponense reached a peak in September and May, while the lowest resource density was in March. Resource density for E. modestus reached a peak in October and April, and the lowest resource density was in June. Spatially, the biomass of M. nipponense and E. modestus witnessed large fluctuations in different areas. The biomass of freshwater shrimp was higher in the open waters than in the coastal zones during winter and spring. However, the biomass of these freshwater shrimps was lower in the open waters than in the coastal zone during summer and autumn. Besides, biomass of the upper half of the Dianshan lake were overall higher than that of the lower half of the lake. This research provides a basis for the rational management and effective exploitation of the shrimp resources in Dianshan Lake, which also provides a reference for the fishery authorities to delimit areas of enhancement and releasing.

Abstract:The small yellow croaker(Pseudosciaena polyactis) is an important marine fish species and widely distributed throughout the Bohai Sea, the Yellow Sea, and the East China Sea of the Northwest Pacific Ocean. Grey relational analysis was used in this study to examine the relationship between morphological traits and body weight of the small yellow croaker. Body weight and 8 morphological traits(including total length, body length, head length, trunk length, tail length, caudal peduncle length, caudal peduncle depth, and body depth) were measured and analyzed. The results show that the average body weight of female was significantly greater than that of male. The coefficients of variation in body weight(30.598 for female, 27.055 for male) were greater than morphological traits(9.941-12.543 for female, 8.170-13.295 for male). The grey relational degrees between morphological traits and body weight were in the interval of 0.5266-0.6812 for female, 0.5284-0.7116 for male. The descending relational order of the morphological traits in the female samples was total length > body length > trunk length > tail length > caudal peduncle length > body depth > caudal peduncle depth > head length. That of male samples was total length > body length > tail length > trunk length > caudal peduncle length > caudal peduncle depth > body depth > head length. In all the samples, the grey degree of total length was the highest and followed by body length, and the head length was the lowest both in the female and male. This study provided scientific basis for the small yellow croaker breeding selection on growth traits.

Abstract:Illegal, unreported and unregulated(IUU) fishing is a serious global problem, and IUU fishing practices include the violation of national and international laws, misreport of catches quotas or species, escape from national or international fishery organization control, etc. IUU fishing jeopardizes the marine ecosystem, food safety, fishermen livelihood, also causes tax evasion, and even transnational crime, such as slavery at sea, especially man and child trafficking. To analyze IUU fishing problem, it's not enough just to know about IUU fishing places, we should also master how IUU catches come into market in the end. From this perspective, this paper takes the main wild-catch seafood exporting from China to USA for example. To analyze China's IUU fishing situation, first of all, through the quantification in 2014 China's main export wild-catch seafood(pollock, salmon, crab) to USA, according to the volume of IUU fishing in proportion, and comparing with the main exporting countries, we can find that the IUU catch scale is large exporting into the United States. Then taking the supply chain as the breakthrough point, we can summarize the reasons as follows:First, the supply chain of wild-catch seafood lacks transparency and traceability. Second, all three species undergo transshipping from Russia and are processed in China before re-export to the United States and all three have been linked to high levels of illegal fishing. When analyzing the policies in USA combating IUU fishing in recent years, especially the U.S. Seafood Traceability Program, it takes trade control as mechanism to combat IUU, and it's also a great test to the traceability of seafood from our country. Finally, considering the latest international instrument combating IUU fishing, i.e. Voluntary Guidelines for Flag State Performance, we can not only learn some specific measures about strengthening sanctions against IUU fishing as legislation, but it's also a test for our country combating in IUU fishing.

Abstract:Tidal channel is one of the major tidal flat landforms. The Jiuduan Shoal in Yangtze River Estuary was taken as the object in this paper. Three different types of tidal channels in panchromatic band remote sensing data received from Landsat 8 satellite on February 15, 2015 were selected. Firstly, the top-hat transformation is to eliminate the problem of the backgrounds of uneven brightness accurately, if the method of maximum between-class variance(Otsu) is used directly; Then, Otsu is used to find an optimal threshold to make the maximum variance between tidal channel and background, obtaining a binary image; Thirdly, the broken tidal channel is connected by morphological dilation, and non-target is removed by morphological removal. Finally the skeleton of tidal channel is extracted and cropped, and the complete information of tidal channel is gained. Visual analysis and quantitative analysis are used to evaluate the accuracy of the information of tidal channel. The result shows that the method combining Otsu with mathematical morphology can be used to extract tidal channel information efficiently. The average accuracy can reach 93.0%, missing error and redundance error are 7.0% and 0.5% respectively.

Abstract:In recent years, China's turbot farming industry has been trapped in the mire of oversupply, quality safety and price falling. The regional brand construction may be an important approach to solve these problems. Regional brand construction should be based on a certain extent of industrial agglomeration. This paper therefore uses those criteria of location quotient and industrial concentration to estimate the agglomeration level of turbot farming industry in China, and constructs a theoretical model on the basis of industrial agglomeration, then takes the "Xingcheng turbot" brand as an example to verify the conclusion of the model. The results show that the industry agglomeration of turbot farming industry in China is mainly concentrated in Liaoning, Shandong and Hebei Provinces, and industrial concentration in Xingcheng city is most obvious. The resources, product, market and technological advantages, industry policy guidance and the services of industrial organizations can promote the construction of the brand. But this brand construction process also faces many problems, such as the lack of technical leading enterprise, the lack of overall strategy of the regional brand planning, the existence of "free rider" and "prisoner's dilemma". It is hereby recommended that leading enterprises be encouraged to organize medium and small turbot farms to work closely, establish fish farmers' associations and let the association be the owners of brands. It is also strongly suggested to establish a brand marketing fund and encourage brand-owning farmers to jointly fund advertising and marketing.