Abstract:In order to study the genetic diversity and phylogenetic relationship of four wild-type or breeding populations (Oreochromis niloticus, O. aureus, O. mossambicus, GIFT Strain O.niloticus) and three red tilapia varieties (Chinese Taiwan, Israel, and Malaysia), sequences of mitochondrial cytochrome oxidase subunit I (COⅠ) were amplified by PCR and aligned. 180 polymorphic sites and 98 haplotypes were defined in 324 samples, with an average haplotype diversity of 0.944 and nucleotide diversity of 0.036. The negative Tajima's D values of neutral test were detected in GIFT, O. mossambicus and O. aureus populations, which indicated population size expansion after a bottleneck effect and/or purifying selection. The genetic distance of 7 tilapia populations was from 0.000 to 0.071, and the population genetic differentiation index (Fst) ranged from 0.016 to 0.994. Genetic population differentiation analysis (AMOVA) indicated that the majority of variation (70.78%) was attributed to variations among populations, whether grouping or ungrouping, reaching a very significant level. In this experiment, the purity of O. aureus was high, and the genetic diversity of the other six populations was rich. The population genetic structure of seven populations of tilapia was analyzed, which enriched the genetic background data of tilapia populations in China, and provided guidance for the utilization of tilapia germplasm resources, especially red tilapia.

Abstract:The purpose of this study was to preliminarily investigate the role of sox9 gene in gonad development and sex differentiation in Takifugu obscurus. The full-length cDNA sequence of sox9 gene in Takifugu obscurus is successfully cloned through the design of degenerate primer amplification, RACE and Real-time PCR technology, and subsequently its corresponding bioinformatics characteristics and the level of tissue and expression were also analyzed. The results showed that the full-length of Takifugu obscurus sox9a gene is 1 248 bp (NCBI accession number:MH218818), including a 684 bp ORF, encoding 227 amino acids; the 5'UTR is 297 bp and the 3'UTR is 267 bp. The full-length of Takifugu obscurus sox9b gene is 1 941 bp (NCBI accession number:MH218819), including a 1 470 bp ORF, encoding 489 amino acids; the 5'UTR is 306 bp and the 3'UTR is 165 bp. The results of homology and phylogenetic analysis showed that the two sox9 sequences shared the highest homology and closest relationship with Takifugu rubripes. The results of multiple amino acid sequence alignment showed that the HMG box domains of the two Sox9 amino acid sequences were highly conserved in mammals and fish. Quantitative fluorescence PCR analysis showed that the two sox9 genes are ubiquitous in all tissues of female and male fish, and they were most highly expressed in the hypothalamus of female fish, a little in the testis, and very little in the ovary. Overall, except for a few tissues, the expression of two sox9 genes in tissues of females was generally higher than that of males. The purpose of this study was to understand the genetic characteristics and physiological functions of sox9 in Takifugu obscurus, and to explore the molecular regulation mechanism of sex differentiation and gonadal development.

Abstract:In order to monitor the carrying status of pathogenic genes and the prevalence of potential pathogenic strains of Vibrio parahaemolyticus from shrimp in Shanghai, the polymerase chain reaction (PCR)and enterobacterial repetitive intergenic consensus sequence-polymerase chain reaction(ERIC-PCR)were applied to detect pathogenic genes and to make genotyping analysis of 1 standard V. parahaemolyticus strain and 19 V. parahaemolyticus strains isolated from shrimp in Shanghai. The results showed no tdh and ORF8 genes were detected in 19 isolated strains and only 1 strain carried trh gene, while the tox RS/new gene was detected in 14 positive strains and the carrying percentage was 73.7%.The AP1 and AP2 genes were detected in specificity V. parahaemolyticus which could cause acute hepatopancreas necrosis disease (AHPND) and the result showed there were 3 positive strains of both genes, and the gene carrying percentage was both 15.8%. The 20 V. parahaemolyticus strains were divided into 7 groups by ERIC-PCR, and the discrimination index(DI) was 0.811,which indicated ERIC-PCR have a good genotyping capability. According to the results of ERIC-PCR, the method could distinguish strains obtained from different periods of time effectively, while the distinction among different geographical strains was not obvious. These results suggested that the carrying percentage of pathogenic genes in V. parahaemolyticus from shrimp was relatively low, while there was a risk of prevalence of new pathogenic strains. These results will provide reference for the prevention and control of V. parahaemolyticus strains in shrimp farms.

Abstract:The spectrophotometry and high performance liquid chromatography (HPLC) methods were used to identify the different pigments between whole red(WR) and whole white (WW) coloration of Oujiang color common carp (Cyprinus carpio var. color). The results of spectrophotometry methods showed the concentration of carotenoids in WR skins were significiantly higher than that in WW skins (P<0.05), bur no difference of pteridine was found between WR and WW skins (P>0.05). Then, the HPLC results revealed that a large mounts of astaxanthin, lutein, and several unknown carotenoids were detected in the eyes, skins and fins in WR, but not detected in WW tissues. The highest concentration of astaxanthin was found in WR fins[(28.00±3.61) mg/kg], and the highest concentration oflutein was found in WR skins[(62.34±4.93) mg/kg]. These results indicated that the carotenoids play a key role in the red coloration formation in Oujiang color common carp, the white color is caused by the deficiency of carotenoids, and the pteridines may have no effects on the red coloration formation in Oujiang color common carp. This study provides insight into white and red coloration formaiton in Oujiang color common carp.

Abstract:In order to study the genetic diversity and genetic structure changes of the selected population through complete diallel crossing in Sanjiang River system, six groups of hybrid Progenies (PearlRiver♀×Heilongjiang River♂(ZH), Heilongjiang River♀×Pearl River♂(HZ), Yangtze River♀×Pearl River♂(CZ),Yangtze River♀×Heilongjiang River♂(CH),Pearl River♀×Yangtze River♂(ZC),Heilongjiang River♀×Changjiang River♂(HC),Heilongjiang River♀×Heilongjiang River♂ (HH), Yangtze River♀×Yangtze River♂ (CC) and Pearl River♀×Pearl River♂ (ZZ)). The microsatellite sequence genetic variation of 9 grass carp populations was analyzed. The results showed that the average number of alleles N_a) was (5.75-12.33), the average number of effective alleles N_e) was (3.8077-6.3065), the average observed heterozygosity (H_o) was (0.7682-0.9036), the average expected heterozygosity (H_e) was (0.8385-0.6210), and the polymorphism information content (PIC) of 12 microsatellite loci in 9 populations of grass carp was high. They were 0.892, 0.823, 0.857, 0.894, 0.927, 0.859, 0.850, 0.859, 0.859, 0.907, 0.929, 0.879, 0.749 and 0.869 respectively, showing high polymorphism loci (PIC is from 0.749 to 0.929). UPGMA phylogenetic tree based on Nei's genetic similarity and genetic distance of different populations showed that among 9 populations, Heilongjiang River♀×Pearl River♂(HZ)and Yangtze River♀×Pearl River♂(CZ) clustered first, indicating that the genetic relationship between the two combinations was closer, and the genetic distance between Pearl River♀×Heilongjiang River♂(ZH)and Heilongjiang River♀×Changjiang River♂(HC) combinations was the farthest. The purpose of this study is to provide reference value for grass carp breeding in the future, lay a foundation for further species renewal and genetic improvement of grass carp, at the same time, provide a solution to the current degradation of grass carp germplasm, and provide a theoretical basis for the breeding of grass carp fine strains.

Abstract:Although wild Chinese mitten crab (Eriocheir sinensis) offsprings in the Yangtze River basin have better culture performance, the culture performance of different size juveniles is still unclear. Therefore, this study was conducted to compare the growth, survival rate, precocious rate, yield, feed conversion ratio (FCR), final mean body weight and size distribution of wild Eriocheir sinensis offsprings during juvenile culture stage. The results illustrated that:(1) During the growth phase of each month, the average body mass of small-size group juveniles was always lower than that of the large-size group. In the case of female crabs, the weight growth rate (WGR) and specific growth rate (SGR) of the small-size group juveniles were significantly higher than those of the large-size group between June-July and August-September (P<0.05). In terms of male crabs, the WGR and SGR of the small-size group juveniles were significantly higher than those of the large-size group between June-July and July-August (P<0.05).(2) The average body mass of normal coin-size juveniles in the small-size group was lower than that of large-size group, but the survival rate was higher than that of large-size group. The yields of the two group juveniles were slightly different, but there was no significant difference (P>0.05). No precocious crabs were finally found in the small-size group.However, the large-size group juveniles had a certain precocious rate. The FCR of small-size group was significantly lower than that of the large-size group (P<0.05). (3) As for the final size distribution, the small-size group juveniles were mainly concentrated from 0 to 6.00 g, and its proportion was 80.09%. The large-size group juveniles were mainly concentrated from 3.00 to 9.00 g, and its percentage was 70.56%. There are differences in the culture performance of different size juveniles of wild Eriocheir sinensis offsprings during juvenile culture stage. This provides reference for germplasm resource evaluation and exploitation.

Abstract:In order to study the effects of six metal elements, i.e. Mn, Mg, Fe, Cu, Zn, and Co on the color of pearls, Hyriopsis cumingii from the same breeding pond were selected, and the different shell elements were analyzed for dark purple and light purple. The difference between the purple and white pearls cultivated in the white Hyriopsis cumingii was analyzed, and the correlation between the metal element content and Lab color parameters of the pearl was analyzed. The results showed that:the four metal elements of Mn, Mg, Fe, and Co exhibited the highest content in deep purple pearls,the Fe was not detected in the white pearl; Cu was slightly reflected in the pearl with a light purple inner shell; the other groups were not detected. Zn content was not detected in all color pearls. Correlation analysis between the content of metal elements and the color parameters of pearls showed that the Fe content of the pearls in each color group was positively correlated with the dE value (R²>0.83), and the Mg content was negatively correlated with the L value (R²>0.80). The Mn content was positively correlated with the a value (R²>0.64). Only in the dark color group, the negative correlation between the Co content of the pearl and the L value was the highest (R²>0.94). The contents of metal elements in mantle and interstitial fluid of different parts of Hyriopsis cumingii were further compared and analyzed. There were significant differences in the contents of Fe in mantle at different sites in Hyriopsis cumingii group (P<0.05), and the highest in site 1. There were significant differences in the contents of Mn and Co in mantle of site 2 in different groups of Hyriopsis cumingii (P<0.05). The content of Co in the dark purple mussel was significantly higher than that in the other two groups. There was a significant difference in Mg content in the interstitial fluid of the white mussel groups (P<0.05). The color of freshwater purple pearls is correlated with the contents of Fe, Mg, Co, and Mn.

Abstract:Qingtian rice-fish coculture system is one of the first pilot sites of Global Important Agriculture Heritage System (GIAHS) designated by FAO in 2005. The optimization of rice-fish coculture mode such as the selection of optimal rice density in the coculture system will be much helpful to the local promotion of this rice fish coculture model. In this study, 3 rice planting density (by different line and plant spacing) were chosen in order to compare the effects of the rice spacing on the rice growth and yield, the survival rate (SR) and specific growth rate (SGR) of the fish (Cyprinus carpio var. color). The 3 rice cultivation densities (high, medium and low density) were plant spacings of 20 cm×30 cm, 30 cm×30 cm and 40 cm×30 cm, respectively. The results showed that:the tiller number and biomass of rice at low density (40 cm×30 cm) were significantly higher than those of the high density groups after elongation stage; there were obvious advantages of the rice stem characters at low density (40 cm×30 cm) among the 3 densities; and the cultivation density had no significant effect on rice yield. The grey correlation analysis showed that the greatest correlation with rice yield was the panicle length among the rice stem characters, and the greatest correlation with rice yield was the 1000-grain weight among rice yield compositions. The SGR of fish reached the highest value 4.54%±0.03% at the medium density (30 cm×30 cm), which was extremely significantly higher than that at the high density (20 cm×30 cm) 3.62%±0.04%. The survival rate of fish was not significantly different among treatments. Based on rice growth and production efficiency, the medium-density (30 cm×30 cm) of Qingtian rice-fish coculture system can be the priority to be used to get faster growth rates of fish while ensuring rice yield.

Abstract:This study was conducted to monitor and analyze the water quality and the dynamic changes of phytoplankton in the closed aquaculture area of Bihai Jinsha in Fengxian of Shanghai were monitored and analyzed and the pollution and potential risks during the aquaculture process was analyzed. The investigations took place in April, July, October 2016 and January 2017. Water quality surveys showed that DIP, DIN and COD concentration remained relatively high in April, July and October. Among them, DIP and DIN concentrations were highest in April, while the highest values of COD concentrations occurred in July. From October to January, the water quality improved significantly at the end of the cultivation. Phytoplankton was found to have a total of 42 species of 7 Phyla, of which most were in autumn and summer and it showed obvious four-season succession. The species with the highest dominance in the four seasons were Chroomonas acuta, Chlorella, Anabaena circin alis and Oscillatoria, and it is worth noting that Chlorella is a dominant species in all seasons. The high abundance of phytoplankton is focused on the summer and autumn. The Shannon-Wiener diversity index (H') and evenness index (J) were from 0.709 to 2.088 and from 0.440 4 to 0.870 7 respectively. The analysis showed that the stability of the community structure of phytoplankton was poor and the water pollution was heavy. The environmental factors affecting the abundance of phytoplankton were nutrition concentration and temperature, and the dominance of Anabaena circinalis and Skeletonema costatum were higher in autumn and both in summer and autumn, respectively, which may cause the risk of red tide. It is necessary to control the aquaculture capacity, improve water quality, and optimize breeding environment.

Abstract:In order to optimize preparation process of reed-based biochar, base on the single factor test to examine the effects of three parameters, i.e. pyrolysis temperature, ammonia mass fraction and impregnation ratio (ratio of biomass feedstock to ammonia mass) on the adsorption performance of reed-based biochar, by the Box-Benhnken Center combination design experiment and the response surface method, the activation process parameters were optimized. The results showed that all three factors had an effect on the specific surface area of biochar, and the significant effects are:pyrolysis temperature>ammonia mass fraction>impregnation ratio. The optimum activation process parameters were the pyrolysis temperature 620℃, the ammonia mass fraction 8%, and the impregnation ratio 1:5. The surface area and iodine value of prepared activated carbon under this condition was 334.49 m²/g and 585.52 mg/g, respectively,which were better than the samples which were not optimized. The experimental and theoretical values(335.2 m²/g、582.288 mg/g)were basically consistent. The response surface model fits well with the actual situation, and the effective feasibility of the model was verified.

Abstract:The 2017 East Pacific Ocean Ecosystem Ecopath model was established and compared with that in 1997.The results showed that:the overall energy conversion efficiency of the ecosystem was 18.78%, indicating that the energy utilization efficiency had reached the optimal level. The evaluation of the ecosystem structure and function showed that the System Omnivory Index and the Connectance Index were 0.323 and 0.272, respectively. The indices indicated that the cohesion degree of the functional group and the complexity of the food web structure were low, which showed that the ecosystem in our study was susceptible to external environmental factors and fishing pressure. The ratio of total primary production to total spirometry was 2.593, which revealed that the ecosystem was immature. The total system flow, total biomass, and total circulation flow indicators were compared between the two phases, and the ecosystem scale and the food web complexity increased in 2017 and the maturity which was still in the development stage. It was assumed that there are uncertainties in the production statistics of large and small-sized individuals of yellowfin tuna and bigeye tuna. Three ecosystem models at different levels were constructed, which showed that the statistical error in production significantly affected our understanding of the ecosystem structure. Therefore, the trophic structure of different size groups and their impacts on the ecosystem should be fully considered.

Abstract:Based on the average sea surface temperature (SST)from May to September, the Schaefer model and the Fox model were used to estimate the catch for the autumn cohort of Todarodes pacificus.It is assumed that the ΔU (residuals of catch per unit effort between the observed and predicted values)calculated form the traditional surplus yield models were correlated with SST, and the SST-based surplus yield models were established. According to the overall development of the autumn cohort of T. pacificus fishery since the 1960s, the total catches from 1985 to 2014 were analyzed separately i.e.from 1985 to 1993, from 1994 to 2002, and from 2003 to 2014. According to with/without SST and whether to segment with SST, three Schaefer models and three Fox models were constructed respectively. Results indicated that the segmented Schaefer model-SST was the best, there was a negative linear correlation between ΔU and SST(P<0.05), and the catch decreased with the increase of temperature from 18 to 23℃. It is suggested that:the model establishment process should be segmented according to the different time periods, which can improve the model fitting; the segmental Schaefer model-SST can be used to evaluate the future catch to provide some reference for related resource management when calculating the maximum sustainable yield.

Abstract:Using the 335 Scomberomorus niphonius samples collected from off East China Sea and Yellow Sea from September 2017 to March 2018, the relationship between otolith and growth was studied by means of function fitting, variance analysis and wavelet analysis, taking TL,TW,DL,DW,VL,and WL as the basic morphological parameters. Based on the samples of 335 Scomberomorus niphonius collected off East China Sea and Yellow Sea between September 2017 and March 2018, the relationship between the ontogenetic shape changes of otoliths and growth was studied by the basic morphological parameters of otolith length, otolith width, dorsal length, dorsal width, ventral length and wing length, using the methods of function fitting, the ANOVA,the Least Significant Difference (LSD) analysis and wavelet analysis. The results showed that the otolith of Scomberomorus niphoniusis milky white, approximate rectangular, the back convex, the front concave, the outside had more protruding small teeth, serrated, the overall bending to show the tile shape. There was no significant difference between the left and right sagittal otolith. The weight of the otolith and 6-item morphological parameters were significantly correlated with the fork length, and all of them were the best fit results of the exponentiation function. With the growth of Scomberomorus niphonius, the morphological characteristics of the otolith varied significantly with the fork length, and the total length of the otolith was increasing, and the dorsal and ventral regions continued to shrink to the center of the otolith. The length of the posterior region increased, and the wing length increased, with the overall appearance of vertical shrinkage and horizontal growth trend.

Abstract:In order to understand the variation in population structure of Antarctic krill in the Scotia Sea in winter and to explore the overwintering mechanism of Antarctic krill, using the samples collected randomly from fishery survey from May to August 2017, the population structure of Antarctic krill in the Bransfield Strait and the South Georgia Island was studied. The results indicate that the monthly sex ratios are not significantly different and the proportions of females are higher than those of males, and the sexual maturity stage has no significant difference between months. Overall, female krill remains immature throughout the winter months, with a few exceptions.For male krill, in May, the number of immature male is lower than that of matures, the number of immature male is more than that of matures in June, the proportion of immature males is higher than that of mature males in July, and all individuals are immature in August.For the Bransfield Strait and the South Georgia Island, as a whole, the number of mature krill decreases since the onset of winter,while the number of immature krill increases gradually. Through the comparison to the historical data, it can be seen that the population structure of Antarctic krill significantly varies inter-annually and annually in the Scotia Sea in the winter.

Abstract:The development, utilization, conservation and management of fish resources are an important part of the sovereign rights of coastal countries in the exclusive economic zone(EEZ). The fishery factor is sensible to consider in the EEZ delimitation. Based on the analysis of the United Nations Convention on the Law of the Sea (UNCLOS) on the delimitation of EEZ, this paper analyzes five international judicial precedents for the delimitation of EEZ. This paper analyzes that fishery factor may be one of the factors which influence the final EEZ boundary determination. Whether the fishery factor has been taken into account and what role it played depend on the importance of fishery to the socio-economics of one party or both parties, and whether this importance role has sufficient evidence to prove its existence.The impact of the fishing activity on the delimitation of the exclusive economic zone is mainly whether the fishery could be applied to test the implied boundary for the EEZ delimitation, the nature and limit of the boundary, and the fairness of the interim boundary. China advocates that the EEZ boundary determination with its maritime neighbors should be settled through agreements. The ruling of international judicial precedents constitute to some extent the basis of international law for the delimitation of agreements, and it has an important reference role for agreement negotiation.

Abstract:Carbon sink fisheries generally refer to such fishery production activities that can facilitate biological absorption of CO₂ in the water and therefore remove carbon by harvesting hydrobiont; while in a specific sense, they refer to culturing, breeding and harvesting alga and filter-feeders to remove carbon from water and store or reuse it. Mariculture plays a vital role in transformation from the traditional mode to modern carbon sink mode. Sustainability with stable production can integrate and advance carbon sink fisheries into the strategic national Blue Granary development. However, such advancement and integration can only be initiated by a series of technological innovations like the choice of aquacultural variety with high carbon fixation, scientific combination of the aquatic life and deep-sea cage culture as well as some administrative innovations like state effort in marine ranching, international blue carbon trade and the Belt and Road cooperation in mariculture. Marine ranching is both the joint from carbon fisheries to Blue Granary and the embodiment of all the innovations.

Abstract:The variation trend and current situation of number and engine power of marine fishing vessels, fishing structure and fishing production in the South China Sea (Guangdong, Guangxi and Hainan Provinces) from 1979 to 2017 were analyzed, based on the data of China Fisheries Statistical Yearbook and relevant information on fishery resources and fishery production in the South China Sea. After the comprehensive implementation of the total number and power control system for marine fishing vessels, the rising trend of fishing vessels in the South China Sea has been controlled, and even generally declined in recent years. However, the total tonnage and engine power of fishing vessels are basically rising. Since 2002, the total tonnage of motor fishing vessels in the South China Sea has increased by 45% and the total engine power has increased by 13.7%. In 2017, motor fishing vessels under 44.1 kilowatts accounted for 77.5%. The fishing production in the South China Sea has been gradually controlled in recent years. In the past five years, the fishing capacity in the South China Sea has been about 3.4 million to 3.8 million tons, and the trawler and gillnetter production, which has great destructiveness to fishery resources, accounts for 72% to 74%. There are some problems in the marine fisheries of the South China Sea, such as the lack of fishing production data, inadequate control of fishing effort and the unreasonable structure of fishing operation. It is suggested to establish and improve the system of statistics and verification of catches by relying on fishing ports, reduce the capacity of offshore fishing, expand offshore fishery orderly, constantly promote public participation in fishery management, and enhance the transparency of fishery management.

Abstract:As one of the most important economic fishes in China, Lateolabrax maculates, with high annual output, considerable profit and delicious taste, is loved by consumers all over the country. Lateolabrax maculates is rich in nutrients, protein, polyunsaturated fatty acids and trace elements. Therefore, it is easy to be spoiled. That is to say, it is very important to apply appropriate preservation techniques to extend shelf life and maintain its nutrition and flavor. The research progress of preservation technology of Lateolabrax maculates in recent years is summarized in order to provide reference for the further research of preservation technology of Lateolabrax maculates. Up till now, preservation technology of Lateolabrax maculates has included irradiation, ultra-high pressure, low temperature, preservatives, packaging technology, combined preservation and so on. It was found that before the storage of Lateolabrax maculates, irradiation was better than ultra-high pressure treatment for better sterilization and less influence on the sensory quality. During storage, super chilling was a good choice for lower cost than ice storage and better preservation than cold storage. As for the temperature change during transportation of Lateolabrax maculates, preservatives can reduce the damage caused by temperature change, which also reduced the cost to maintain the certain temperature. In future, there will be more biological preservatives and compound preservatives to be used. Besides, modified atmosphere packaging and active packaging have a significant effect on maintaining the freshness of Lateolabrax maculates, which needs more research and development. Finally, it can be concluded that freshness-keeping technology will develop towards combined preservation which will be more efficient, safe and economical.

Abstract:Based on the derivatization of R-phycoerythrin (R-PE) with o-phthalaldehyde (OPA), a novel fluorescence ratio probe for the detection of o-phthalaldehyde was constructed. The primary amino groups of R-phycoerythrin were exposed after unfolding by sodium dodecyl sulfate (SDS). In the alkaline environment of β-mercaptoethanol, a blue fluorescent isoindole compound could be derived by reacting with o-phthalaldehyde. In this probe, the fluorescence signal of R-phycoerythrin gradually weakened with the increase of the concentration of o-phthalaldehyde, whereas the blue fluorescence signal was gradually enhanced, and a strong-weak fluorescence change constituted a ratio fluorescence probe. The results show that under the carbonate buffer condition of pH 10.5, the optimal detection time of the probe is from 3 to 6 minutes, the linear detection range is from 5 to 100 μg/mL, the correlation coefficient is 0.992, and the limit of detection is 1.7 μg/mL. The proposed fluorescent probe can sensitively detect the OPA in disinfectant.