Abstract:The short-wave-sensitive 1 (sws1) gene was knocked out using CRISPR/Cas9 technology in zebrafish. Under UV illumination, the numbers of melanocytes were calculated and the expression levels of melanocyte formation related genes pomc and asip, retinoic acid synthesis related genes raldh2 and raldh3 were determined in the dorsal and ventral skins of AB wild type and sws1^-/- zebrafish. It showed that:the number of melanocytes in the dorsal skin of sws1^-/- mutant was significantly less than that of wild type after exposing to UV light for 60 and 100 days;qRT-PCR showed that the expression of pomc in the dorsal skin of sws1^-/- mutant zebrafish was significantly lower than that of wild-type after 100-day UV illumination; the expression of raldh2 in the dorsal skin of sws1^-/- mutant zebrafish was significantly lower than wild-type after 100-day UV illumination. This research suggested that UV light could influence the expression of raldh2 and the synthesis of retinoic acid through sws1, and then affected the expression of pomc to regulate melanocyte formation. This result provided a basis for understanding the molecular mechanism of sws1 regulation on melanocyte formation of the fish skin.

Abstract:Although mechanisms of sex determination in sexual reproduction are diverse, there is a common feature of germ cells to undergo mitotic division and proliferation, following the entery of meiosis to develop oocyte or sperm. It is unclear whether germ cells are sexually dimorphic during the mitotic proliferation prior to the onset of meiosis, or how spermatogenesis or oogenesis is initiated. Tsn (Translin) protein products were significantly higher in gsdf deficient (gsdf^-/-) XY ovaries than that in normal (gsdf^+/+) XX ovaries, revealed by the proteomic expression profiles among normal (gsdf^+/+) XX ovaries, normal (gsdf^+/+) XY testises and gsdf (gonadal soma-derived factor) deficient (gsdf^-/-) ovaries in medaka (Oryzias latipes), suggesting that Tsn protein expression might be regulated by dmy (DM domain on Y chromosome) and downstream Gsdf male signals in gonad development. The full-length Open Reading Frame (ORF) fragment of tsn was cloned from gonadal cDNA libraries in medaka. Phylogenetic tree and alignment of amino acid sequence analysis shows that Tsn is well conserved in vertebrates with the high homology of amino acid sequence sharing between medaka and zebrafish (Danio rerio). Although the tsn transcription was detectable in multiple tissues by reverse transcription PCR and real-time quantitative PCR, the testicular level of tsn mRNA was significantly higher than that of ovaries in medaka. Immunofluorescence revealed that cystic germ cells positive to anti-medaka Tsn antibody were significantly increased in gsdf^-/- XY ovaries than that in gsdf^+/+ XX ovaries as a control. This is consistent with the previous report of high Tsn protein products in gsdf^-/- XY ovaries detected by the high-throughput proteomics analysis. A conclusion has been drawn that Tsn-mediated germ cell proliferation was promoted in male pathway under the regulation of dmy (DM-domain on Y chromosome) but inhibited by Gsdf signaling. Lack of Gsdf released the inhibition of Tsn expressing germ cell proliferation during medaka testicular differentiation. The results may provide clues for defining sexual difference between male and female germ cells in the process of vertebrate mitosis and proliferation.

Abstract:Cyprinus carpio slc15a1 gene is a low-affinity, high-volume transporter of small peptides and peptide analogs into various tissue cells using a proton gradient inverse concentration, and this gene also plays an important role in the immune response. To investigate the changes of slc15a1 (slc15a1a and slc15a1b) genes in the immune response mechanism in carp at the protein level, the fragments of slc15a1a and slc15a1b genes containing part of the antigenic determinant cluster were ligated to pET-32a(+) by adding the double digestion sites BamH Ⅰ and Hind Ⅲ, and the corresponding expression vectors were constructed, and polyclonal antibodies to slc15a1a and slc15a1b genes were successfully prepared. The potency of the antibody was detected by ELISA, and the potency of mouse anti-Slc15a1a and Slc15a1b obtained were 8.1×10⁵ and 2.7×10⁵. When infected by Aeromonas hydrophila, the highest protein expression levels of Slc15a1a and Slc15a1b increased 3.39 and 2.85-fold, respectively, compared with the blank control, indicating that the polyclonal antibodies prepared in this experiment have high affinity and specificity and exhibit strong immunogenicity, which can promptly induce an immune response in the organism. Slc15a1a responded rapidly with high expression at 3 h and 6 h after A. hydrophila infection and began to show a decrease in expression level after 12 h, but Slc15a1b maintained a more stable high expression response between 3 h and 24 h, indicating a certain expression difference between Slc15a1a and Slc15a1b. During infection, the expression of Slc15a1a was largely higher than that of Slc15a1b, so the slc15a1a gene may be the major gene of the slc15a1 gene and may play an important role in the common carp immune response process.

Abstract:Phospholipase C (Phospholipase C, PLC) is a class of enzymes related to membrane proteins, which play an important role in signal transduction pathways. Onchidium reevesii that inhabits the intertidal zone can perceive the local tidal laws. In order to explore the role and molecular mechanism of phospholipase C in O. reevesii in tide sensing, in this experiment, we used the ganglion of O. reevesii as the experimental material. The cDNA sequence of PLC gene was cloned by RACE-PCR technology, and bioinformatics analysis and qRT-PCR experiment were performed. The results showed that the full length of the cDNA of the PLC gene consists of 2 578 base pairs, the open reading frame(ORF) is 1 881 bp, the 5'non-coding (UTR) region is 337 bp, the 3'non-coding region (UTR) is 340 bp, and there is an AATAAA tailing signal at the end, which encodes a total 627 amino acids. The result of amino acid sequence comparison showed that the PLC gene of O. reevesii has the highest match with the phospholipase C-like protein 2 amino acid sequence of Pomacea canaliculata, with a similarity of 88%, followed by the phospholipase C-like protein 2 amino acid sequence of Crassostrea virginica, and it is consistent with the classification of traditional morphology. Using the low frequency sound in the tide in the laboratory to stimulate the O. reevesii, the expression of PLC gene at different frequencies was detected by fluorescence quantitative PCR. The results showed that the expression of PLC was basically stable when the stimulation sound wave frequency was 40 Hz-70 Hz. When the frequency was increased to 160 Hz-310 Hz, it was in a state of low expression. When the sound wave frequency reached 220 Hz and 280 Hz, it was in a state of high expression, indicating that this gene plays an important role in the low-frequency perception of O. reevesii. This experiment lays a theoretical support for further understanding of the tidal sensing function of the O. reevesii.

Abstract:Temperature-dependent sex determination is a notable model of phenotypic plasticity; however, its underlying molecular mechanism remains unclear.As a typical TSD species, the red-eared slider turtle (Trachemys scripta) has its offspring gender completely determined by incubation temperature. In order to provide more basic data for illustrating the TSD mechanism, transcriptome sequencing was performed on T. scritpa early embryonic gonads of stage 16 at different temperature (male-producing temperature (MPT) and female-producing temperature(FPT)) in this study. IlluminaHiseq 2500 high-throughput platform was used for transcriptome sequencing. A total of 474 differentially expressed genes were screened out, among which 283 genes showed MPT higher expression and 191 genes showed FPT higher expression. By comparing with NR, Swiss-Prot, GO, COG, KOG and KEGG databases, 60 GO functional annotation classifications and 139 KEGG metabolic pathways were obtained. According to functional annotation of differentially expressed genes, these candidates included:sex determination and differentiation related conserved genes, such as Dmrt1, Sox9, Foxl2, etc; steroid hormone metabolism related genes, such as Cyp11b1, Hsd11b2, etc; heat-sensitive protein coding genes, such as Hspb6, Dnaja4, Serpinh1, etc. Several selected candidates were verified by quantitative PCR and immunofluorescence. In conclusion, some new temperature sensitive and hormone metabolism related factors were found out from RNA-seq data of turtle embryonic gonads, providing basic support for illustration of the molecular mechanism of TSD.

Abstract:For further realizing the genetic diversity and provide experimental data of germplasm resources for Triplophysa brevicauda in the upper reaches of Lancang River in Yunnan Province, 77 individuals including 4 geographic populations (Biaocun, Yezhi, Lidi and Wu Nonglong) were analyzed. After sequencing, the total length of 921 bp of D-loop control region were obtained, and 22 variable sites (including 8 singleton variable sites and 14 parsimony informative sites) and 21 haplotypes were identified in whole populations, respectively; the haplotypic diversity (H_d) and nucleotide diversity (π) of Triplophysa brevicauda in the upper reaches of Lancang River was 0.837-0.942 and 0.005 16-0.005 72, respectively; among them, the highest H_d was identified in Lidi population, the lowest H_d was identified in Biaocun population, and a genetic character of "high H_d low π" was presented; The results of AMOVA indicated that most of genetic variation (97.91%) came from within population and little of genetic variation (2.09%) was came from between populations; no significant genetic differentiation was detected between the comparison groups (F_st=-0.021 3, P=0.805); the farthest genetic distance (0.005 67) of Triplophysa brevicauda was identified between Biaocun and Lidi population, and the closest genetic distance (0.005 11) was found between Yezhi and Wu Nonglong population; no recent population expansion event happened in the evolutionary history of Triplophysa brevicauda, which was proved by the evidence of non-poisson distribution of nucleotide mismatch and insignificant neutral test result (Tajima's D=0.624, P=0.737;Fu's F_s=-0.669, P=0.377). The results showed relatively abundant genetic diversity and low level of genetic differentiationo of Triplophysa brevicauda in the upper reaches of Lancang River.

Abstract:The family Cepolidae (bandfishes) is a group of small Perciformes fishes with flat and red body. Most species live in self-made burrows in muddy or fine-sand areas. There is a special larval stage characterized by the enlargement of the superior occipital bone and the operculum.This family is distributed in the tropical and subtropical areas of the Indo-West Pacific and East Atlantic Ocean. It has been recorded sporadically in China. The history and current situation of the study on the family Cepolidae were investigated in detail. The cepolid specimens collected by the major fish research institutions in China was examined, and the development process of larvae and the basic morphology of adult were introduced. The related specimens preserved in the main fish research institutions in China were examined and the species of Cepolidae in China were determined. According to the morphological characteristics,there are 7 species belonging to 3 genera of Cepolidae in China. Citation of scientific name of these species and their countable and quantifiable characters were listed. The morphological characteristics and geographical distribution were briefly described. A key to the classification of genera and species was compiled.

Abstract:The development of vertebral column and appendicular skeleton of the larvae and juveniles of Chaeturichthys stigmatias was described. A series of wild specimens of 4.7-45.1 mm in body length were cleared and stained for both cartilage and bone. The observation showed that the notochord was not segmented, and cylindrical in specimen 4.7 mm NL. With the appearance of neural arches, haemal arches and hypurals in specimen 5.3 mm NL, the vertebral column started to develop. The neural and haemal arches in specimen 7.1 mm NL extended to neural and haemal spines, respectively. Segmental bone rings formed in specimen 7.1 mm NL. The ossification of vertebral column from anterior to posterior, and completely ossified in specimen 22.9 mm SL. The trunk and caudal vertebra were formed in 15 and 25-28 cervical vertebra segments, respectively. The appendicular skeleton developed in the following sequence:pectoral fins, caudal fins, second dorsal fins and anal fins, first dorsal fins and pelvic fins. Cartilage of pterygiophore of pectoral fins, coracoid-scapula cartilage, and partially ossified cleithrum were observed in specimen 4.8 mm NL. The pectoral girdle was ossified in specimen 16.8 mm SL. The pelvic fins began to form in specimen 8.9 mm SL, and ossifying occurred in specimen 17.0 mm SL. The development of dorsal fins and anal fins began with the appearance of 13 and 11 hyaloidin pterygiophores in specimen 6.6 mm NL. The second dorsal fin was formed earlier than the first dorsal fin. The dorsal fins and anal fins began to ossify from anterior to posterior in specimen 13.0 mm SL and specimen 12.1 mm SL, respectively. The first fin rays of second dorsal fins and anal fins were transformed into dorsal spine and anal spine in specimen 22.7 mm SL and specimen 20.6 mm SL. The development of the caudal fin began with the appearance of the hypurals in specimen 5.8 mm NL. The caudal fin was basically formed, with two pieces of epural, one piece of urostyle, one piece of uroneural, one piece of parhypural and three pieces of hypurals, and the second and third hypurals were combined together in specimen 10.9 mm SL. The caudal fin was ossified in specimen 24.3 mm SL. The study on the early development of the vertebral column and the appendicular skeleton in C. stigmatias is important for classification and functional adaptation during early development environment.

Abstract:To understand the features of phytoplankton communities and their main impact factors, two cruises were conducted in the coastal waters of Rizhao in February and August 2016.Phytoplankton species and dominant species composition, abundance, community diversity and environmental factors were analyzed, and the cluster analysis, multi-dimentional scaling (MDS) ordination techniques, Pearson correlative analysis were applied in this study to reveal the relationship between phytoplankton community structure and environmental factors. In total, 92 taxa were identified, which belonged to 41 genera and 3 phyla. Among them 73 were diatoms,18 were dinoflagellates,1 was Chrysophyta. The dominant species was Guinardia delicatula in winter, and Chaetoceros lorenzianus, Chaetoceros constrictus in summer.The cell abundance of phytoplankton ranged from 2.20×10⁶-6.12×10⁷ cells/m³ with an average of 2.61×10⁷ cells/m³ in winter and from 3.75×10⁴-5.70×10⁶ cells/m³ with an average of 1.22×10⁶ cells/m³ in summer.Pearson correlation analysis showed that salinity, depth of water, dissolved oxygen(DO), nitrates, nitrite, ammonium salt, total nitrogen, heavy metal (Zn) in the sea water had the great influence on abundance of phytoplankton.Compared with Shannon Wiener diversity index (H') method, multivariate statistical analysis could better reflect the water environment quality in the coastal waters of Rizhao.

Abstract:There are various reasons for the miniaturization of zooplankton in subtropical areas and the current view of many scholars is inclined to the predation pressure of fish. In this experiment, Pseudorasbora parva and Daphnia magna that are common in the middle and lower reaches of the Yangtze River were chosen as the research object. The two species were cultured in the same container but P. parva couldn't prey directly on D. magna. On such a premise, a cross-over experiment was designed to study the effects of visual stress and kairomone on the growth, body size and reproduction of D. magna. The study was divided into four groups, namely, the non-visual stress kairomone group, the visual stress kairomone group, the non-visual stress non-kairomone group, and the visual stress non-kairomone group. Results indicated that:the body length of D. magna increased more rapidly in the absence of kairomone; The spine length of D. magna increased more rapidly in the absence of kairomone, and the spines were longer under visual stress; The average reproduction of D. magna was 2.89 times higher in the absence of kairomone, and the visual stress kairomone group had the fastest death rate. Although biological manipulation has reduced the number of cladoceran predators, the residual fish kairomone in water remains to inhibit the cladoceran in aquatic ecosystems. The results showed that fish not only have direct feeding pressure on cladoceran, but also have indirect effects on cladoceran body size, growth and reproduction through visual stress and kairomone.

Abstract:To evaluate the community structure and changes of zoobenthos in summer and autumn under different submerged vegetation coverage, in July (summer) and October (autumn) of 2018, four coverage levels were selected in Shihoudian Lake, which were 25%, 50%, 75%, and 90% (C-25, C-50, C-75, C-90), and the control group is the area without submerged plants (C-0), and the respectively determined and analyzed the water physical and chemical parameters and zoobenthos community structure characteristics of each area. The results showed that:Submerged plants effectively reduced the concentration of total nitrogen (TN) and total phosphorus (TP). A total of 19 species were collected, belonging to 3 phyla, 4 classes, and 19 genera. Among them, the proportions of aquatic insects, gastropods, oligochaetes, and Lamellibranchia species were 68.42%, 15.79%, 10.52% and 5.26%, respectively; The number of benthic species in groups C-90, C-75, C-50, C-25 and C-0 was 10, 8, 11, 9 and 3, respectively. The Shannon-Weiner diversity index and Margalef richness index of zoobenthos increased first and then decreased with the increase of submerged vegetation coverage. Among them, the two diversity indexes of Zoobenthos in the C-50 group were significantly higher than those in other groups (P<0.05). Coverage, season, and the interaction effects of the two have significant effects on the density and biomass of zoobenthos (P<0.05), and the biomass of gastropods in the C-50 group in summer was significantly higher than that of other groups (P<0.05). Transparency, TDS and SPC are the main environmental factors affecting the distribution of Zoobenthos in summer and autumn. When the coverage is about 50%, the concentrations of TDS, SPC, TN and TP are the lowest, and the number of benthic species, Shannon-Weiner diversity index and Margalef richness index are the highest.

Abstract:Spatial-temporal distribution of macrobenthic community was studied in the coastal waters of Rizhao in July, October, December 2018 and April 2019. A total of 119 macrobenthic species were identified during the surveys, including 62 species of polychaetes, 36 species of crustaceans, 12 species of molluscs, 4 species of echinoderms and 5 species of other groups. According to the Index of Relative Importance, the community was dominated by Micronephthys oligobranchia, Sternaspis scutata, Mediomastus sp., Cylichna biplicata, and Spionidae und.. Abundance and biomass varied seasonally with the mean abundance of 191 ind./m² and mean biomass of 6.71 g/m². Values of average Shannon-Wiener species diversity index (H'), Pielou's evenness index (J), and Margalef's richness index (d) were 2.912, 0.934 and 2.139, respectively. The CLUSTER results based on Bray-Curtis similarity indicated that the similarity among macrobenthic community groups was low and the distribution pattern of macrobenthic community showed seasonal characteristics. According to the Abundance-Biomass comparison curve (ABC), community from one season (April, 2019) was slightly disturbed.With the rapid development of coastal zones and the continuous impacts of human activities, the dominant species of macrobenthic community changed obviously, showing a decreasing trend of abundance, biomass and H', and the contamination tolerant species Paraprionospio pinnata had gradually became the dominant species.

Abstract:In order to accelerate the renewal of largemouth bass (Micropterus salmoides), a complete diallel crossing experiment was carried out using the introduced American population (US) and the domestic cultured population (YZ) as the base populations, and four paired combinations of USUS, USYZ, YZUS, and YZYZ were obtained, and the one-year-old fish growth performances of their offspring were compared. The results indicated that USYZ had a significant heterosis (P<0.05) in body weight, standard length, and absolute weight gain rate, and consistently had the highest coefficient of variation. Meanwhile, two hybrid groups (USYZ, and YZUS) had median parental heterosis for all growth traits. The body weight, standard length, total length, head length and body height of the USYZ hybrids have supernatural hybrid heterosis and were higher than those traits of YZUS hybrids. Additionally, the results of the path analysis revealed a highly significant positive correlation between total length, body width, body height, and body weight of the offspring (P<0.01); different from USUS, the coefficient of determination for body weight via body width was higher than that via body height in USYZ, YZUS, and YZYZ. Based on diallel cross mating design, the best mating group was investigated in terms of growth traits of hybrid offspring, so as to provide a basis for genetic improvement and breeding of M. salmoides in practice.

Abstract:In order to investigate the effect of Bellamy aquarata size on the predatory behavior of Eriocheir sinensis, the differences of size selection, predation rate, predation behavior and shell-breaking techniques of small and large sizes[shell width:(38.0±2) mm; (43.0±2) mm] Eriocheir sinensis preying on three sizes[shell width:(5.5±0.5) mm, (7.5±0.5) mm, (9.5±0.5) mm] were analyzed by video surveillance system. The results were as follows:The larger the size of B. aquarata, the lower the selection index and predation rate of E. sinensis. (P<0.05). The probability of capture upon encounter and the probability of consumption upon capture of E. sinensis and B. aquarata are consistent with the trend of predation rate, but encounter rate of E. sinensis and B. aquarata is opposite to the trend of predation rate; The smaller the size of B. aquarata, the greater the probability of consumption upon capture of B. aquarata (P<0.05). B. aquarata size significantly affected the proportion of stationary time, moving time and handling time (P<0.05), but had no significant effect on the proportion of searching time (P>0.05). The larger the size of B. aquarata, the higher the proportion of successful avoidance (P<0.05); the larger the size of E. sinensis, the lower the proportion of successful avoidance of B. aquarata (P<0.05). The proportion of crushing tactics of E. sinensis on small and medium sized B. aquarata was significantly higher than that on large sized B. aquarata (P<0.05). E. sinensis preferred to prey on small-sized B. aquarata. Whether the crab can consume after capture is an important link in the predation of E. sinensis. Shell-breaking techniques of the E. sinensis to the square ring edge snail change with the size of the square ring edge snail.

Abstract:The pituitary structures and the immune signals of FSHβ and LHβ of the six fish species (the areolate grouper Epinephelus areolatus, blacktip grouper E. fasciatus, red spotted grouper E. akaara, flagtail grouper Cephalopholis urodeta, honeycomb grouper E. merra and white-streaked grouper E. ongus) widely distributed along the coastline of Japan were investigated.The results showed:the gonadal development of areolate grouper, blacktip grouper, red spotted grouper and flagtail grouper was in the immature stage, however the honeycomb grouper and white-streaked grouper in the mature stage. The pituitary structures consisted of neurohypophysis (NH) and adenohypophysis (AH). The AH was further divided into the rostral pars distalis (RPD), the proximal pars distalis (PPD) and the pars intermedia (PI) from left to right. The immune signals of FSHβ and LHβ were detected in the PPD area or in the PPD and PI areas in six species, and the FSHβ signal intensity was stronger than the LHβ signal in six species. These results indicate that, FSHβ may play more important roles than LHβ in the gonadal development of six species when they were around mature stages. Based on the investigation of the six species of groupers along the coastline of Japan, the information of the interrelation between gonadal development and FSHβ and LHβ hormones function was obtained which may provide the basic biological data and theoretical basis for resource conservation and artificial propagation.

Abstract:In order to study the effects of salinity on the survival, growth and antioxidant status of juveniles Scatophagus argus, fish with average body weight of (6.27±0.28) g were exposed to different salinities groups (0, 5, 10, 20, 30, 35) and reared for 60 days, and the survival rate and growth status were counted. The superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione S-transferase (GST) activities, glutathione (GSH) and malondialdehyde (MDA) contents in liver, gill and muscle tissues were determined. The results showed that:The survival rate was 97.78%~100%, and there was no significant difference among the different salinities groups (P>0.05). When the salinity was 5, the final body length, body weight and weight gain rate showed the maximum, while these values showed the minimum when the salinity was 35. The specific growth rate (SGR) was (0.96±0.01)% at the salinity of 5, which was significantly higher than other groups (P<0.05). The optimal breeding salinity of juvenile Scatophagus argus with body mass of (6.27±0.28) g was 7.5, obtained by the quadratic regression model fitting based on the SGR. The SOD and CAT activities in the liver of fresh water group and salinity 35 group were significantly higher than those in other groups (P<0.05), the GPx activity and MDA content in liver were also at a higher level. There were no significant differences in the activity of GST and GSH content among different salinities (P>0.05). The results showed that:The survival rate of Scatophagus argus juveniles was high in the salinity range of 0-35, but juvenile Scatophagus argus grew faster in the low permeability environment; The fresh water and hypertonic environment caused a certain degree of oxidative stress in fish. It is recommended to raise young juvenile Scatophagus argus in the salinity range of 5-10.

Abstract:The water quality identification index method was used to evaluate and analyze the comprehensive water quality of the inflow, aquaculture tail water and the discharge water from aquaculture tail water treatment system in the freshwater aquafarm.Total solid suspended matter (TSS), organic matter (COD_Mn), total ammonia nitrogen (TAN), total nitrogen (TN) and total phosphorus (TP) were taken as single factor evaluation indexes and comprehensive evaluation indexes. The comprehensive water quality was evaluated and analyzed according to Environmental Quality Standard for Surface water(GB 3838-2002) or Requirement for Water Discharge from Freshwater Aquaculture Pond (SC/T 9101-2007). Research indicated that:TN was the main pollutant in the inflow of the aquafarm. TP and TSS were the key risk factors of pollutants in the ponds. Aquiculture tail water treatment system played an important role in the integrated water quality purification of aquiculture tail water. After the eastern pond tail water was treated by the aquiculture tail water treatment system (S1), the comprehensive water quality was improved (I_ΔX1.X2=13%), and the main pollutant TN was significantly improved (I_ΔX1.X2=23%). After the western pond tail water was treated by the aquiculture tail water treatment system (S2), the comprehensive water quality was slightly improved (I_ΔX1.X2=9%). The comprehensive water quality of the discharge water was equal to or better than that of the inflow in the aquafarm by aquaculture tail water treatment system to purify aquaculture tail water, and it met the first-level discharge standard of SC/T 9101-2007, and had no negative impact on the environment of adjacent natural waters, but also had a slight improvement effect.

Abstract:A high performance liquid chromatography-tandem mass spectrometry (HPLC-MS)method or perfluorooctane sulfonic acid (PFOS) analysis in water was established. The water sample was pretreated with a 0.22 μm PP filter membrane, and then 200 mL pretreated water was enriched with a Poly-Sery HLB solid phase extraction column. The enriched extraction column was eluted by passing it through 10% aqueous methanol, after which the elution chamber was evacuated and the column was washed again with 4 mL methanol. And then ACQ MITY MPLC BEH C₁₈ chromatographic column was used to separate the eluent in the negative ion multi-reaction monitoring mode detection, fragment ion m/z=80, by internal standard method quantitative analysis, using a 0.1% formic acid aqueous solution-methanol solution as mobile phase. Under preferred conditions, PFOS was linear in the concentration range 0.01-50 μg/L with a correlation coefficient r>0.99, and the method limit of detection was 0.25 μg/L. The spiked recoveries ranged from 82.1% to 104.5% and the relative standard deviations (RSD) ranged from 2.34% to 5.64% for PFOS at the spiked concentrations of 0.2, 2.0, and 20 μg/L, respectively. The PFOS content in the actual water samples was below the detection limit, the lake water spiked recovery rate was between 84.75%-112.2%, RSD<5.62%, and the aquaculture water sample spiked recovery rate was between 81.7%-118.6%, RSD<7.51%. The established method can accurately detect PFOS in environmental water.

Abstract:International Convention for the Control and Management of Ships Ballast Water and Sediments has entered into force in China,and it is very important to control the discharge of ballast water.However,the discharge of ballast water is difficult to meet the Convention's standards.In order to ensure the effectiveness of the treatment results of Ballast Water Management System (BWMS), IMO has revised the standards for water quality characteristics of Guidelines for Type Approval (G8).Due to the differences of water quality characteristics in various natural water areas, additives are often used in water synthesis for BWMS type approval inland-based test to meet the water quality characteristics standards. The effect of additives on the water quality characteristics of fresh water, brackish water and sea water in the type approval test of BWMS is focused on, and stable and effective additives for the synthesis methods of the type approval test water for BWMS.The results showed that the synthesis method of source nature water with calcium lignosulphonate, glucose,corn starch,chitosan and kaolin was possible to improve the water to satisfy the requirement of IMO.

Abstract:The North-west Pacific region is polluted seriously by marine litter, but has yet to establish legal system of cooperative governance. There are three typical institutionalized cooperative patterns, which are the North Sea and North-East Atlantic, the Baltic, and the Mediterranean patterns. By choosing two dimensions of the heterogeneity of the political system and the heterogeneity of economic development to analyze the three patterns' characters, generation mechanism, and the situation of North-west Pacific region, it can be found that the North-west Pacific region should choose the Mediterranean pattern, which are the fittest and the easiest to achieve. In order to absorb DPR Korea to join in, the North-west Pacific region, using the form of "Convention and Protocol", needs to formulate encouraging framework convention, which covers the contents of management structure and implement mechanism, etc. Based on that convention, the protocol to prevent marine litter pollution in the North-west Pacific region, which covers the concrete contents of the linkage to the domestic law, execution and supervision, and dispute settlement, should be formulated. And to make the intergovernmental organizations work at full capacity is also necessary. The cooperative governance pattern adopted for marine litter can pave the way for and lay the solid foundation for the integrated environmental cooperative governance legal system in the North-west Pacific region.

Abstract:In order to explore the influence of the division of different intervals of Trachurus japonicuson on its population parameters and stock assessment, the length frequency with the data of the fork length of T.japonicus in the Beibu Gulf from 2006 to 2018 was reconstructed, and logistic curve fitting and length Bayesian biomass estimation method (LBB)were used to estimate the first sexual maturity fork length (L₅₀), asymptotic fork length (L_∞),relative natural mortality (M/k),relative fishing mortality (F/k), total mortality (Z/k), optimal fork length-at-first-capture (L_{c_opt}), exploitation rate (E) and other population parameters. The differences in population parameters under different intervals.The results show:The fork length of first sexual maturity ranges from 157 mm to162 mm; The average values of L_∞, M/k, F/k, Z/k, and L_{c_opt} of T. japonicusin intervals length are 248 mm, 1.38, 6.92, 8.28, and 156 mm, respectively; The relative biomass B/B₀ is less than 0.5, and E is greater than 0.5; The results of population parameters estimated by reconstruction length frequency of intervals are different, and the fluctuations are more obvious with the increase of intervals.Studies have shown that the biomass of T. japonicus is relatively low and is in an over-exploited state. At the same time, it is recommended to determine the length of a certain fish interval based on the number of samples, length composition and biological characteristics.

Abstract:The spawning ground of Ommastrephes bartramii is divided into empirical spawning ground and speculated spawning ground. By analyzing the correlation between the proportions of the appropriate sea surface temperature (SST) area in the total area (P_S) in the empirical spawning ground, speculated spawning ground and feeding ground each month, a linear prediction model was established by selecting the month with significant statistical relationship between P_S and catch per unit fishing effort (CPUE). Under the two scenarios of RCP4.5 and RCP8.5, the recruitment of O. bartramii resources was predicted using this model and the P_S of the statistical significant months in 2025, 2055 and 2095. The results showed that the suitable SST range of the empirical spawning ground of O. bartramii would move northward under the climate change scenario, and would reach the northernmost edge of the empirical spawning ground in 2095. The average P_S of the empirical spawning ground between January and April decrease, but the change might not be significant. The suitable SST range of the speculated spawning ground also would move northward, reaching the northernmost edge of the speculated spawning ground in 2095, which is beyond the range of speculated spawning ground. The average P_S of the speculated spawning ground between January and April would decrease, and the change might be significant. The suitable SST range of the feeding ground moves northward and tends to expand. The average P_S of the feeding ground between July and October showed a downward trend with a significant change. The result of correlation analysis showed that there was a significant positive correlation between P_S and CPUE of speculated spawning ground in February and March. In the future, the CPUE of O. bartramii will decline. By 2025, the CPUE of O. bartramii will be (208.87±5.46) ton per vessel. By 2055, it will be (198.00±47.92) ton per vessel. By 2095, it will be (154.35±48.72) ton per vessel. Decline of O. bartramii resources will be 60.08% in 2095 compared with 2000.It is suggested that proper measures compatible with climate change be adopted for sustainable development of O. bartramii fishery under the maintenance and management mode and framework of NPFC.

Abstract:The gradient-dependent correlation scale method was used to construct the temperature vertical structure of yellowfin tuna fishing ground based on Argo real-time observation profile. The results showed that, compared with the traditional method, the root mean square error of the vertical temperature profile constructed is significantly reduced. At the depth of the thermocline, the maximum difference between the two was 0.45℃. Besides the thermocline, the temperature deviation between the constructed temperature profile and the actual observed true value was great (about±0.5℃), the other water layers were almost zero. The results of statistical analysis in August 2017 showed that the suitable temperature range of yellowfin tuna in the near surface layer (5 m) of the western and central Pacific Ocean is 28.5-29.5℃, and with the increase of depth, the temperature gradually decreases, and the suitable temperature range is about 11.0-12.0℃ at 300 m. There was obvious thermocline in each fishing point, the corresponding average thermocline upper and lower boundary depth and thermocline strength are about 80 m, 270 m and 0.08℃/m respectively, and the thermocline strength is approximately proportional to the catch. These conclusions further verify the reliability of the method.

Abstract:In order to assess the spatial distributions of fish community in upper and lower approach channels of the Three Gorges shiplock, the hydroacoustic surveys were carried out in January, May, October in 2018 and May 2019, respectively. Survey areas were set as:area Ⅰ (Jingjiang River), area Ⅱ (upper approach channel), area Ⅲ (lower approach channel) and area Ⅳ (Sandouping section). Fish body length was estimated based on target strength and the estimates showed that fish body length in area Ⅰ, area Ⅱ and area Ⅳ ranged from 2.5 to 5.0 cm, while that in area Ⅲ ranged from 7.0 to 20.0 cm. Average fish densities in area Ⅰ, area Ⅱ, area Ⅲ and area Ⅳ were (99.53±47.78) ind./1 000 m³, (57.37±33.45) ind./1 000 m³, (61.51±1.72) ind./1 000 m³ and (30.61±15.75) ind./1 000 m³, respectively. The fish densities of low water levels in area Ⅰ and area Ⅱ were significantly higher than those of high water levels, while fish densities of lower water levels in area Ⅲ were significantly lower than those of high water levels. Fishes in area Ⅰ and area Ⅱ were mainly distributed in middle-lower water layer at different periods, however fishes in area Ⅲ tended to move to shallow water layer (less than 6 m) at high water levels, but deep water layer (more than 8 m) at low water levels. Spatial distributions of fishes in the upper and lower approach channels were greatly influenced by the water level of the Three Gorges reservoir and ships passing the lock.

Abstract:In the design and research of bionic squid, it is very important to study the hydrodynamic characteristics in the pitching posture, and the completion of pitching motion is the foundation for the realization of its behavior bionics, basic swimming motion and function.In order to study the hydrodynamic characteristics of the bionic squid's flexible tentacles in its pitching posture, the bionic squid was selected as the biomimetic object, and the flexible tentacle bending model at different pitching angles was established through the biomimetic squid simplified model.According to the 3D model, the hydrodynamic characteristics of biomimetic squid in different pitching postures and different bending degrees of tentacle were analyzed and compared by numerical simulation method.Through analysis:when the biomimetic squid uses flexible tentacle to coordinate swimming, it provides a favorable moment for the completion of its pitching posture, which is more conducive to the change of its pitching posture and swimming direction when it swims at high speed.When the bionic squid completes the pitching posture, it can adjust the posture and swimming direction more timely and efficiently by changing the bending degree of the tentacle, and it requires less energy consumption.The results may lay a foundation for the research on the flexibility and swimming behavior of biomimetic squid.

Abstract:In order to study the influence of the floating state of the bait boat on its stability, and to provide reasonable guidance for the installation position of the feeding machine, the bait boat developed by Shanghai Ocean University is taken as the research object, and the computational fluid dynamics method and overlapping grid technology are used to calculate the floating state of the bait boat and its righting arm curve under different working conditions. Thereby the influence of the floating state of the bait boat on its stability was analyzed, and the best installation position of the feeding machine was obtained. The results show that the impact of the floating state of the bait boat on its stability can not be ignored. Under the same load, the different installation positions of the feeding machine will cause different degrees of trim by bow or stern. The greater the trim angle, the worse the stability, and the stability of the bait boat is the best when it is upright; The fixed installation position does not guarantee that the bait boat remains upright under different loads. It should be installed in a position that can make the bait boat upright when fully loaded. The overall stability is best when the feeding machine is installed in the F position (X=-40.85 mm). The overall layout of the bait boat should also ensure that the trim angle is equal to zero when fully loaded.

Abstract:The catamaran bait boat is one of the feasible schemes to realize bait sprinkling in the crab pond. In the presence of water plants in the channel, in order to reduce the cruise resistance and improve the endurance of the bait boat, two new bottom profiles, sharp bottom and round bottom, were designed in this paper. Based on the Reynolds average N-S equation, the dynamic calculation models of the boat under different draughts and speeds are constructed. Taking the flat bottom boat as the contrast boat, the CFD numerical calculation and the sink test resistance are compared and analyzed,and the data error is less than 9.6%, which shows the effectiveness of the calculation model. The results show that:the round bottom boat has better resistance reduction effect at the speed of 0.50-2.00 m/s, and the resistance reduction rate is 3.92%-16.27% compared with the flat bottom boat; the round bottom boat can reduce the sliding friction resistance between bottom and water plants; the economy of bait boat is at the speed of less than 1.50 m/s and the draft is less than 0.18 m. The further test results of the round bottom boat show the effectiveness of the proposed optimization scheme.

Abstract:The physiological indexes and intestinal microflora of Cherax quadricarinatus overwintering were studied at different concentrations of nitrite. The acute toxicity of nitrite to Cherax quadricarinatus was studied by conventional bioacute toxicity test method, and the semi-lethal concentration of 96 h was 22.0 mg/L and the safe concentration was 2.2 mg/L. Four groups of nitrite experimental groups were set up, respectively, group A (0 mg/L), group B (0.5 mg/L), group C (2.3 mg/L) and group D (5.0 mg/L).Samples were taken after 6 weeks of stress. The results showed that:There was no significant difference in survival rate, hypertrophy and liver index in four groups (P>0.05), but the survival rate, weight gain rate and body length increase rate of group D were the lowest. Hepatopancreas histology analysis:With the increase of nitrite concentration, the arrangement of hepatic tubules tended to be disordered and the sizes of hepatic tubules became different. The connective tissue between hepatic tubules decreased and vacuoled, especially in group D. Physiological biochemistry indicators analysis:SOD activity decreased with the increase of nitrite concentration. In hepatopancreas, group A was significantly higher than the other three groups (P<0.05), and group D was significantly lower than the other three groups (P<0.05). In muscle, group A was significantly higher than group C and D (P<0.05), and group D was significantly lower than group A and B (P<0.05). MDA activity increased with the increase of nitrite concentration. In hepatopancreas, there was no significant difference among the four groups (P>0.05). In muscle, group A was significantly lower than group C and D (P<0.05). Immune-related indicators decreased with the increase of nitrite concentration. In hepatopancreas, ACP and AKP activities of four groups were significantly different (P<0.05), the highest in group A and the lowest in group D. In muscle, ACP activity in group A was significantly higher than that in other three groups (P<0.05). AKP activity in four groups was significantly different (P<0.05), with the highest in group A and the lowest in group D. UL activity had no significant difference in each group (P>0.05). The activity of energy metabolic index TG decreased with the increase of nitrite concentration, and the TG activity in group A was significantly higher than that in group D (P<0.05). Intestinal flora analysis:Nitrite stress increased the proportion of Enterobacteriaceae to a certain extent, and the diversity of group D was the lowest and that of group A was the highest. Nitrite caused the decrease of intestinal flora diversity.

Abstract:Five seawater samples were collected near Zhongshan Station during the 34th Antarctic Expedition from China,through Illumina high-throughput sequencing, the microbial composition and microbial community structure were identified.At the phylum level, Proteobacteria and Bacteroidetes were the most abundant, followed by Cyanobacteria.Flavobacterium and Psychrobacterwere dominant genera, each of them exceeded 20%. The genus UBA1315 was found for the first time in Antarctic seawater, and the function annotation results showed that there are abundant DNA repair genes in the seawater microorganism, which suggested that it might be helpful to adapt to the harsh environment.By comparison of the microbial community structure between Zhongshan Station and the upper waters of the Ross Sea,the results showed that the microbial diversity is higher in Ross sea upper water,and the abundance of the bacterial is different.In the Antarctic and Arctic seawaters, Proteobacteria,Bacteroidetes and Cyanobacteria are ubiquitously and abundantly present. Proteobacteria is the dominant phylum of waters from both polar regions, and Cyanobacteriais is most abundant in the Southern Ocean. This study has preliminarily revealed the microbial composition of the seawater near Zhongshan Station, and provided some basic data for further research on marine microbial resources investigation and development of Zhongshan Station in Antarctica.

Abstract:In order to effectively improve the extraction rate of astaxanthin from shrimp shell waste, Macrobrachium rosenbergii, Euphausia superba and Litopenaeus vannamei are used as raw materials, and organic solvent extraction is utilized to compare the three types of shrimp shells through single factor experiments. The extraction effect, and the orthogonal optimization of the extraction process parameters of astaxanthin from Euphausia superba shrimp shells; the use of infrared spectroscopy to compare the astaxanthin standard with the samples from three kinds of shrimp shells, and to verify the shrimp in the sample purity; with V_C as a control, the antioxidant capacity of astaxanthin in three kinds of shrimp shells was explored. The results showed that from Macrobrachium rosenbergii, Euphausia superba and Litopenaeus vannamei,astaxanthin was extracted with dichloromethane, the extraction temperature was 30℃, and the extraction time was 2 h. The maximum extraction volume could be obtained. The extraction amount from E. superba is significantly higher than the astaxanthin in the shells of Litopenaeus vannamei and Macrobrachium rosenbergii. The material-to-liquid ratio has different effects on the extraction amount from E. superba astaxanthin among the three. The extraction volume of Euphausia superba and Litopenaeus vannamei under the condition of 1:30 g/mL material-liquid ratio reached the maximum value of 234.72 μg/g and 172.21 μg/g, while Macrobrachium rosenbergii has a maximum extraction volume of 88.69 μg/g under the condition of a material-liquid ratio of 1:20 g/mL. The optimal conditions for extracting astaxanthin from Antarctic krill shrimp shells are as follows:material-to-liquid ratio 1:30 g/mL, extraction temperature 30℃, and extraction time 2.5 h. Under these conditions, the amount of astaxanthin is significantly increased to 245.01 μg/g. Infrared spectroscopy proved that the purity of the astaxanthin obtained in the experiment was high, and the vibration absorption peak of the functional group was very similar to the standard astaxanthin. Through antioxidant experiments, it is found that the astaxanthin in the three kinds of shrimp shells has good antioxidant activity, and the astaxanthin in Macrobrachium rosenbergii shell has the hight antioxidant activity.