Abstract:This study determined the embryonic and post-embryonic development of the fish [(Day)]. The morphological and ecological traits in each development phase were described in detailusing a microscope fitted with a digital camera. The fertilized eggs of (Day)are viscous and ovoid, with a diameter of (0.60SE). Embryonic development lasted 65 h and 34 minwhen incubated at a water temperature of (20.0±and was categorized into seven physiological stages.Post-embryonic development was divided into a larval, a juvenile, and a growth stage based on morphological variationin the yolk sac, gas bladder, scales, body color, and barbels. Newly-hatched larvae reached an average length of(2.0, the yolk sac was completely absorbed 7 days after fertilization.After 16 ds maintained temperature, the gas bladder drum at the rear edge of the gill cover had grown to a visiblesize, the body color had deepened, and the red pigment of the heart was discernible, indicating that had moved from the larval to the juvenile life stage. During the juvenile stage, individualsreached an average length of (8.0SE). Juveniles developed sequentially, growing scales, completingdevelopment of the peritoneum, and metamorphosing into young fish at 30 d. Young fish reached an average length of(13.0±

Abstract:To improve techniques of artificial breeding, this research focused on the novel membrane progestin receptor(mPRL) of half smooth tongue sole ünther. The full-length cDNA encoding mPRL wascloned from the half smooth tongue sole by means of homology cloning and RACE PCR analyses. The complete cDNAsequence of mPRL (GenBank accession number: KF277065) was 2 002 bp in length, consisting of a 5′′UTR of 783 bp. The molecular weight of mPRL was17.62 kD. Structural analysis of the translated cDNA suggested that it encoded membrane protein with seven transmembranedomains. Tertiary structure of the mPRL protein showed that it had several binding sites. The rooted phylogenetictree was constructed using the neighbor-joining method on MEGA4.0 for comparative analysis of half smoothtongue sole mPRL and selected vertebrate sequences. The similarity (%, identity) of half smooth tongue sole mPRL incomparison with other representative sequences was analyzed using Clustal X. The results indicated that the halfsmooth tongue sole mPRL was clustered with mPRL of other fish. Half smooth tongue sole had 68% identity withJapanese medaka (). The mPRL mRNAexpression in half smooth tongue sole was detected by quantitative real-time PCR. And found to be widely, althoughnot homogeneously expressed. mPRL transcripts were highly abundant in the brain, ovary, heart, gill, spleen, andstomach. In addition, positive signals were obtained for mPRL mRNA in the pituitary gland, muscle, and intestine, althoughthe resulting transcript levels were lower than in the ovary. Representative sections of ovaries showed the morphologicalcharacteristics during development, which was divided into five stages. The expression level of mPRLmRNA at various stages of oogenensis in the sole showed that the level of mPRL mRNA in the brain and ovary significantlyincreased from stage II to stage V (

Abstract:) is an important commercially cultured fish in China, Japan, andKorea. The rapid development of the Japanese flounder aquaculture has led to problems with various diseases that havereduced growth rates and caused huge economic loss. One way to address these problems is to cultivate strains withcharacteristics such as high growth performance, breeding survival rates, and disease resistance. For this purpose, 38families and a control group were established in 2009. Four to five months after hatching, 33 of the 38 families and thecontrol group were selected for exposure to . The surviving individuals were marked with fluorescent-dye and cultivated in two cement pools. Four hundred days after hatching, lymphocystis disease (LD) broke out inone of the pools containing 16 families and the control group. The average rate of incidence was 62.4%; those families(Families 8, 15, 39, and 104) with disease incidence below 40% were defined as disease-resistant. At the same time, 100fish selected from each family were marked with fluorescent-dye and cultivated in different cement pools. Roughly 580 dafter hatching, breed survival rate (580-BSR) and body weight (580-BW) were determined. For the 38 families, the average580-BSR was 32.0%. There were seven families (Families 5, 8, 27, 75, 90, 119, and 125) with a 580-BSR above55%, and they were defined as high breed survival rate families. Notably, in 6 of the 7 families, at least one parent wasderived from F0750 (Family 50 established in 2007), suggesting that individuals from F0750 may effectively improve580-BSR. Chi-square tests indicated that body weight (400-BW) and total length (400-TL) of the resistant group weresignificantly higher than those of the susceptible group (

Abstract:parents, released fish and recapturedfish DNA, and obtained the mtDNA control areas sequences of these groups. The results showed that 55 parents had 26kinds of haplotypes; and the 129 released fish had 5 kinds of haplotypes, all corresponding to the parents haplotypesdatabase, verified the accuracy of mtDNA markers in the anaylsis of paretal allocation for the released with 70 kinds of haplotypes were identified, amongwhich 330 fish with 17 kinds of haplotypes were corresponded to the parents haplotypes database. These fish had thepossibility to be the released fish. Another 105 fishes with 53 kinds of haplotypes could not be corresponded to the parents’haplotypes database, and we categorized them into non-released fish of Beidaihe. We performed further paternitytests by using 4 high polymorphic microsatellite markers for the 330 might be released ’’ alleles, and were determined as non-released. Bythe combination using of mtDNA and microsatellite markers, we can categorized 310 fish (among 435 recaptured ). In conclusion, we could effectively determine the released from the recaptured ones, and provide basic information for the analyzing of genetic diversity and artificial stock enhancementeffect.

Abstract:Lipovitellin (Lv) is the major proteolytic product of vitellogenin (Vtg) in the ovary and has been widely usedin studies of endocrine disruption. In this paper, a high molecular weight protein was purified from the ovary extracts ofNile tilapia () using gel filtration followed by ion-exchange chromatography. Results of nativepolyacrylamide gel electrophoresis (PAGE), lipid staining with Sudan black B, carbohydratestaining with Schiff reagent,and phosphorus staining with methyl green identified the purified protein as a phosphoglycoprotein. Using westernblotting, the protein was cross-reacted with the anti-goldfish Lv antisera. Native PAGE determined the molecularweight of the protein to be approximately 560 kD, and a single monomer of ~112 kD was detected by the sodium dodecylsulfate (SDS)-PAGE. Based on this characterization, immunogenicity, and molecular weight, this protein wasidentified as the Lv of the Nile tilapia. No degradation was observed under conditions of multigelation or incubation at37

Abstract:Carbohydrates are widely included in aquafeed as the major non-protein energy source owing to theirwide availability and low cost. This study evaluated the effects of the quantity of dietary carbohydrates (25.61%,34.55%, 45.31%, 55.82%, 66.09%) on growth performance, feed utilization, body composition, and the energybudget of juvenile (Selenka) sea cucumbers. Sea cucumbers were given feed with the differentpercentages of carbohydrates for 60 days, with 3-replicates per treatment and 40 sea cucumbers per replicate[ ±SE: (1.67±0.06) g, body weight]. During the experiment, the specific growth rate and feed conversion efficiencyinitially increased then decreased with higher levels of dietary carbohydrates. Based on second-orderpolynomial regression models of these variables, optimal carbohydrate levels for the sea cucumber were estimatedto be 50.15%–53.95%. The protein efficiency ratios and energy consumed were significantly higher in diets with45.31%–55.09% carbohydrates than in those with 25.61%–34.55%, demonstrating that carbohydrates providedenergy for protein sparing. Dietary carbohydrate intake had significant effects on sea cucumber feed intake, fecesproduction, and apparent digestibility coefficient. Optimal carbohydrate intake enhanced the efficiency of nutrientutilization. Whole body, body wall, and intestinal crude lipid content all increased with higher levels of dietarycarbohydrates, where excess carbohydrates resulted in tissue lipid deposition. In diets with 66.09% carbohydrates,the percentage of energy intake used for growth significantly decreased, while energy accounted for by feces, excretion,and respiration increased, indicating that excess dietary carbohydrates reduced energy utilization efficiency.In conclusion, optimal levels of dietary carbohydrate intake promoted growth and feed utilization in theseacucumber, while lipid deposition and energy metabolism variability resulted from excess dietary carbohydrates.

Abstract:Using a complete diallel mating system, growth and nutrient composition of muscle tissue, expression oflipid metabolism enzyme genes, and the relationship between crude lipid content and mRNA levels of a lipid metabolismenzyme were compared between two species of tilapia, . At the end of an experimental period of 100 days, the specific growth rate of pure-bred progeny of GIFTtilapia was significantly higher than that of the two hybrids and the pure-bred progeny of . The feed conversionrate, hepatosomatic index, and viscerosomatic index of pure-bred progeny of were significantly higherthan those of experimental groups. There was no significant difference in the moisture, ash, orcrude protein content.Crude lipid content of pure-bred GIFT tilapia progeny was significantly higher than that of other groups. Total aminoacids, essential amino acids, and dispensable amino acids of pure-bred progeny were significantly lower thanother groups. The rate of essential amino acid formation in four Fgenerations was consistent with FAO/WHO standards.Saturated, single unsaturated, polyunsaturated, and n-6 polyunsaturated fatty acids of pure-bred GIFT tilapiaprogeny were significantly higher than those of the two hybrids and the pure-bred progeny of . Correlationanalysis showed a negative relationship between muscle crude lipid content and mRNA levels of FAS (progeny were significantly lower than of GIFT tilapia or hybrids.Thus, hybridization may increase growth performance of offspring and improve meat quality, as well as enhancing theeffect of selective breeding. Although there were no significant differences in mRNA levels of betweenthe two hybrids of GIFT tilapia, higher muscle crude lipid content may amplify mRNA levels of

Abstract:To investigate the adaptation mechanisms of sea cucumbers to low salinity environments, physiological indices were measured in the coelomic fluid of under acute low salinity stress. Test specimens weighed (16.93±3.08) g ( ±SE) in body weight. Experiments simulated the salinity changes observed in culture ponds in the rainy season. Salinity was gradually lowered from 30 to 18 ppt at a rate of 0.5 ppt/h, where it was maintained for 96 h. Salinity was then increased back to 30 at the same rate, where it was maintained for 24 h. The osmotic pressure of the coelomic fluid was measured directly with a cryoscopic osmometer. Other physiological indices were measured using the corresponding test kits. The results showed that trends of variation in the osmotic pressure, total protein co concentrations of the coelomic fluid were consistent with the changes in salinity. The close relationship of osmotic pressure and water salinity indicate that sea cucumbers osmoregulate their coelomic fluid to approximate levels of environmental salinity. Minimum concentrations of Na⁺, K⁺ and Cl⁻ [(131.15±14.42)±0.24) mmol/L, and (141.76±2.13) mmol/L, respectively] occurred at 18 ppt. After salinity was returned to normal levels (30 ppt), the three indices showed no significant difference from the control group ( concentrations were maintained at higher levels than in the control group, which varied from (3.78±0.49) mmol/L to (6.28±3.69) mmol/L (mean±SE). The Na⁺-K⁺-ATPase activity of the coelomic fluid over 4 d at 18 ppt was significantly higher than at other salinities (-ATPase activity under salinities of 18. This result demonstrated that the osmoregulatory system of the sea cucumber was activated in external environments of low salinity. Variation in Na⁺-K⁺-ATPase activity can alter membrane permeability to maintain the balance of osmotic pressure between the extra and intracellular environments. Compared with the control group, the total protein concentration in the coelomic fluid initially decreased, followed by an increase to a steady value that was then maintained for the duration of the experimental period. Glutamate pyruvate transaminase activity of the coelomic fluid, which can indirectly reflect the condition of protein metabolism, showed no significant change under differing salinities. This result indicated that changes in salinity had little effect on the respiratory metabolism of the sea cucumber and that sea cucumbers can adapt to changes in the external salinity. Osmolarity of the coelomic fluid was strongly dependent on the concentrations of Na⁺, K⁺ and Cl⁻. This experimental work on the adaptation of sea cucumbers to environmental salinity furthers understanding of sea cucumber physiology and ecology and will inform future work on the aquaculture of sea cucumbers.

Abstract:The growth and development of teleost were more or less directly affected by the environmental factors. Salinity is one of the important ecological factors. The influence of salinity on the survival and growth of marine fish has been demonstrated in many studies. However, distinct results were displayed due to the different abilities of tolerance to salinity among fish species. The milkfish (Chanos), which has a nice marine habitat and an efficient osmoregulation, is widely distributed throughout tropical and subtropical Indo-Pacific. This species occurs naturally and is commercially cultured in fresh, brackish, and oceanic waters as well as in hypersaline lagoons. In the present study, the influences of salinity stress on the survival and growth of milkfish juveniles were assessed and the effects of morphometric attributes on body weight were also evaluated. Juveniles of milkfish [mean weight and total length: 0.215±0.083g; 2.850±0.356cm, respectively] were reared at 0 (fresh water), 10, 20, 27 (sea water) and 35 without acclimation, in triplicate, for 30 d cultivation. The survival rate was recorded and the body weight and morphometric attributes of each individual were measured. Results showed, the lowest survival rate was founded at salinity 0 group (73.33%) when compared with other groups (>90%). The juvenile stage is a special stage during the life history of fish, the juvenile developed not as well as the adults, and cannot adapt to the short-term drastic changes of external osmolality, which may be one of the reasons of the high mortality rate at salinity 0 group. On the other hand, however, the highest rates of weight gain rate (573.94±231.58)% and specific-growth rate (6.23% were obtained at salinity 0 group (P<0.01). Meanwhile, there was no significantly difference among other groups (>0.05). The higher weight gain rate and specific-growth rate were also found in the intermediary groups with salinity 20 and 27. It has been suggested that the marine fish often has a better growth rate in water with lower salinity for the reason of fish spending less energy on osmoregulation in such conditions. Although it has not been reported that milkfish require a fresh water environment for any part of its life cycle, it did showed well growth performance at fresh water in many studies. Furthermore, recent studies indicated that the true proportion of energetic cost of osmoregulation remains under debate as thought before. The total length (x₅), postorbital length of head (x₈), caudal peduncle height () were measured by QCapture Pro 6.0 software after the cultivation. The correlation analysis, path analysis and determination coefficients were calculated by SPSS 13.0 software. Significant differences (P<0.01) were found in all correlation coefficients between each morphometric attributes and the weight. The results of path analysis showed that the traits which had the strongest effect on body weight were total length, body length and body height, and the direct effects of morphometric attributes on body weight were different at salinity stress. The analysis of determinant coefficients revealed that the determinant coefficient of body length was the largest (0.94930) in the salinity 0 group. For salinity 10 group, the determinant coefficients of total length and body height were larger compared with other traits, among which total length had a predominant determinative effect (0.33841). For salinity 20 group, the determinant coefficients of total length, body length, and body height were larger, among which body length had a predominant determinative effect (12.15845). For salinity 27 group, the determinant coefficient of total length was the largest (=0.89838). For salinity 35 group, the determinant coefficients of body length, eye diameter, snout length, and body height were larger, among which body length had a predominant determinative effect (0.32091). In addition, the best multiple linear regression equations were established at salinity stress, which will be helpful to the cultivation of milkfish.

Abstract:mirror carp, the acute toxicity and tissue injury of ivermectin for Songpu mirror carp was studied. Ivermectin was given by oral administration to Songpu mirror carp at the dosage of 1.30 mg/kg, 1.69 mg/kg, 2.19 mg/kg, 2.86 mg/kg, 3.71 mg/kg, 4.83 mg/kg, 6.27 mg/kg, 8.16 mg/kg respectively. Blank control and solvent control were sited also. After given ivermectin, the fish were investigated in 96 h; the dead fish were sacrificed at once. Through calculating by SPSS, the 96h LD₅₀ and 95% confidence of LD₅₀ of ivermectin for Songpumirror carp were 4.04 mg/kg and 3.42~4.80 mg/kg, respectively. The results show that with the increase of the dose, the number of red blood cells had no obvious change, the hemoglobin concentration had rised and the white blood cell count had decreased, according to analysis blood cell of the administration group and the control group. By histological examination, the results show that at the dose of 4.83 mg/kg after oral administration of ivermectin, the tissues of Songpumirror carp began to appear obvious pathological changes. Large doses of ivermectin after oral administration, the intestinal villis became necroticed and shed in intestinal cavity, liver cells were atrophied and hepatic sinusoid became larger, tubular epithelial cells became degeneration and necrosis, myocardial fibers became atrophy and degeneration. This study provided some important reference data and theoretical basis for using ivermectin in the process of Songpumirror carp cultivating.

Abstract:pathogenicity and virulence genes ofisolated from diseased Huangsha soft shelled turtle in different areas of Guangxi Zhuang Autonomous Region. An artificial infection test in Huangsha soft shelled turtle was measured on the pathogenicity of the isolated strains, including a PCR assay of detecting the bacterial strains of 6 kinds of virulence genes including . The results were as follows. Forty seven strains of pathogenic T. sinensis contained 9 kinds of bacterium virulence genotypes in all, including + ahp⁺, + ahp^–, – ahp⁺, – ahp^–, + ahp^–, – ahp⁺, – ahp⁺, – ahp⁺ and – ahp^–. Around 48.94 percent of the strains carried all the 6 kinds of virulence gene detected, and the genotype of + Act⁺ was the main virulence genotype. About 95.79 percent of the , and all of them were the virulence strains. Our results also showed that pathogenicity of was the outcome of combined action of multiple virulence genes, among which gene ahal of the isolated strains had correlated action with other virulence genes, whereas the absence of gene A. hydrophila strains to Huangsha soft shelled turtle based on the artificial infection test. Strain which caused a fatality rate at or above 50 percent in Huangsha soft shelled turtle was determined to be a particularly virulent strain, whereas the one caused a fatality rate below 50 percent was determined to be a low virulent strain. Particularly virulent strains carried at least 4 kinds of virulence genes according to our study, and at the same timegenes were both present. Low virulent strains carried only two or three virulence genes besides gene. The study found for the first time that strains which carried only or to Huangsha soft shelled turtleAlt, were prone to missing. Among all the virulent strains, the strains with different genotypes varied significantly in causing fatalities rates in Huangsha soft shelled turtle <0.01). When any virulence gene is absent, the pathogenicity of the strains with the same genotype contributing to Huangsha soft shelled turtle P<0.01), which indicates that pathogenicT. sinensis contributes significantly stronger pathogenicity to Huangsha soft shelled turtle . According to the results of this study, a PCR detection of the virulence gene could be recommended to infer whether a strain is virulent or not, and the co-existence of virulence genes, , could be considered as a reasonable predictor of the particularly virulent strains.

Abstract:A biofloc technology system is a complicated microbial ecosystem that requires some time in culture to stabilize inorganic nitrogen assimilation and the quality biofloc formation. The establishment of a biofloc technology system generally results in the accumulation of ammonia or nitrite. The growth and immune enzymes of the Genetically Improved Farmed Tilapia (GIFT) strain of were examined during the initial establishment of a biofloc technology system. A total of 600 tilapia with an average weight of (24.17± 2.49) g ( ±SD) were raised for 30 days, half in an indoor recirculating aquaculture system (control group) and half in a biofloc technology system (treatment group). Sodium acetate was added to the biofloc technology system at rate of 75% feed to maintain an optimum CN ratio of heterotrophic bacteria. The two groups were fed commercial feed at a daily rate of 2% of total fish body weight. The daily feeding rate was adjusted every 10 days based on the weight of a fish sample. Total suspended solids were maintained at roughly 500 mg/L in the control group. Both systems were maintained at a water temperature of 24–26 with dissolved oxygen (DO) concentrations over 6 mg/L and a pH of 7.0–7.5, which was adjusted using NaHCO₃. A simulated natural photoperiod (12L12D) was used. During establishment of the biofloc technology system, concentrations of ammonia and nitrite rapidly spiked and then decreased, reaching peak concentrations of (60.98± ±SD), respectively. Nitrate concentrations stayed at relatively low levels of 1–15 mg/L. In contrast, nitrate levels rose markedly in the control group, ranging from (73.03±3.29) mg/L to (152.44±1.79) mg/L. Concentrations of ammonia and nitrite, however, were relatively stable and maintained relatively low levels of 5 and 0–3 mg/L, respectively. There was no significant difference between treatments in the activities of alkaline phosphatase, lysozyme, or total superoxide dismutase of the hepatopancreas, head kidneys, and serum; however, total superoxide dismutase and lysozyme activity in the hepatopancreas were significantly lower in the treatment group than in the control. In contrast, the specific growth rate, hepatosomatic somatic index, fullness, and protein efficiency ratio of the treatment group were significantly higher than that of the control group (<0.05), while the feeding rate in the treatment group was lower than the control (>0.05). Relative to the control, the feed conversion ratio in the experimental group was significantly lower (<0.05). Survival was 100% for both groups, indicating no significant stress reaction to biofloc establishment. Moreover, tilapia grew at faster rates in the biofloc system than the recirculating system.

Abstract:As both a source and sink of varieties of elements including nitrogen, phosphorus and sulfur in aquacultureponds water bodies, sediments influence the process of eutrophication as well as the restoration and governance of waterquality. With the increasing demands of large size of tilapia in China, more greenhouses were built for tilapia overwinteringaquaculture. Due to large temperature difference, restricted air flow and water change conditions in aquaculturegreenhouses, NHincreases quickly. It is a great help for water quality regulation and pond sedimentmanagement to study the vertical distribution characteristics of the nutrients in overlying and interstitial waters and theirinterface diffusion rates in tilapia aquaculture greenhouse ponds. Intact overlying and interstitial waters were collectedby peeper (pore water equilibriums) devices from tilapia greenhouse aquaculture ponds in Doumen District, Zhuhai,China. The nutrients of NH-N, NOPOSO -S in collected samples were then measuredby miniaturized photometrical methods using a microplate reader. All measured nutrients had good repeatability betweenthe four peeper groups in the two tilapia aquaculture ponds, and showed distinct vertical distribution patternsrespectively. For instance, NH-N mainly remained in interstitial waters, increased greatly with the depth from 0 cm to6 cm, and tending towards stability deeper than 8 cm; NO-N mainly remained in overlying waters, and decreasedquickly from the depth of 0 cm to 4 cm; NO3-P increased to maximumsfrom the depth of 0 cm to 4 cm, and decreased after the depth of 4 cm; -S mainly remained in overlying waters,and decreased quickly from the depth of 0 cm to 8 cm. The depth related samples were divided into three groups, overlyingwater group, surface layer sediment group (water-sediment interface group) and lower layer sediment group withdistinct differences. Diffusion rates of the nutrients were calculated by the Fick’s First Law. NHPO-P werereleased from the sediment to overlying water, while 24-S in the overlying water were absorbed intothe sediment. NH-N was the main endogenous released nutrient in the tilapia aquaculture ponds with the diffusionrates of 22.44 mg/(m·d) and 16.74 mg/(m·d), respectively. It was relativelyhigh compared with other similar studies, which means that it had relatively high organic matter content in sedimentsof the tilapia aquaculture ponds. -S was the most absorbed nutrients with the diffusion rates of –87.05mg/(m·d) and –91.30 mg/(mreductionmaybe one of the most important way to degrade organic matters in sediments of the tilapia aquaculture ponds.

Abstract:Platevindex mortoni I) gene sequences. Groups of nucleotides T, C, A, G contents to an average of39.54%, 17.56%, 23.07%, 19.83%, showing A + T (62.61%) content is significantly higher than G + C content(37.39%); mitochondrial genome showed obvious anti G migration characteristics.A total of 84 individuals representing5 collection sites were included in the analysis. Overall, 41 haplotypes were defined and 117 polymorphic sites wereobserved. In addition to Hap1 and Hap28 which shared haplotype and 39 haplotypes for each group specific haplotypes,Hap1 is the most widely distributed haplotype, except HN group, distributed in all groups, accounting for 39.3% of allhaplotypes. Xiamen group (XM) and Cangnan population (CN) has the most number of haplotypes, which were 12, andHN group haplotypes at least (6), and 117 polymorphic loci, including 23 single variable sites and 94 parsimony informativesites. Each group of polymorphic loci () show obvious differences, displayed the span from 10 to 85. TheGroups of Zhanjiang (ZJ) and Guangxi (GX) polymorphic loci at least (10), and the Cangnan group (CN) showed themost polymorphism loci in number, followed by the Hainan group (HN). Overall, Cangnan population (CN) haplotypediversity () are the group of high level. Each group of haplotype diversitywas 0.625~0.889, and the difference was not obvious; the nucleotide diversity was 0.002 0~0.057 2, showing obviousdifferences. The populations had both high haplotype diversity(0.835±0.039) and nucleotide diversity(0.057 2±0.006 0). The group number of nucleotide differences (was low, only more than 1, while in HN and CN groups, was high value, which was greater than 30; theentire group also belonged to a higher level, 33.820 7. The AMOVA test of populations based on haplotypefrequencies revealed that 34.02% of the genetic variation occurred within the populations, whereas 65.98% of the geneticvariation occurred among populations. Pairwise fixation index () and genetic distance analysisshowing significant genetic divergence appeared in populations. HN group and the other four groups showedsome genetic distance, and CN group and other groups also showed a large genetic distance. Among small inter groupsof ZJ, XM and GX, the genetic distance between ZJ group and GX group had the minimum genetic distance. No obviousgenetic differentiations occurred among populations of XM, ZJ and GX (>5). While the other group had significantgenetic differentiation, especially in HN group, CN group and other groups generated a high level of geneticdifferentiation of 0.051 3~0.138 6; gene exchange was very small. The occurrence of a moderate geneticdifferentiation in CN group and HN group were = 1.422 2. Whereas, the significant genetic divergencewas found among HN, CN and the other populations, respectively. Haplotype network and phylogenetic treeanalyses also indicated genetic divergence occurred among populations. IBD analysis showed no significant correlationbetween genetic distance and geographical distance. Neutrality test and demographic analyses indicated bottleneck effectmight occur in populations ZJ and GX, population expansion in XM population. The time of expansion of XMpopulation could be 0.12 Ma BP. The phenomenon might occur in Pleistocene period with changes of climate warmingand rising of sea level. In this study, based on the analysis of flat wart mulberry gene, toinvestigate the genetic diversity and genetic differentiation process, aiming for the species conservation of germplasm,and provides the basic data and theoretical basis of the reasonable development of resources and biological evolution.

Abstract:(Dunker, 1861) is a commercial marine bivalve that is found in coastal waters of China, Japan, and Korea from the shallow subtidal to depths of 20 m. It has high nutritive and medical value according to traditional Chinese medicine. In addition, it is adaptable and has high growth rates and great market potential. Currently, this clam is only available from natural sources. Over the last few decades, however, overfishing and environmental pollution have caused dramatic declines in natural stocks of , and production is low and unstable. Fortunately, methods of artificial breeding and cultivation of the jackknife clam are developing. Previous studies on focused primarily on morphological and ecological characteristics, allozyme analysis, and evaluation of its nutrition components. Little is known about the molecular ecology of or its genetic background. Thus, it is important to evaluate genetic differences among populations along the coast of China. In this study, 14 microsatellite DNA markers were used to examine the genetic diversity and differentiation among five wild populations of the grand jackknife clam. A total of 150 samples were collected from Dandong (DD) in Liaoning Province, Qinhuangdao (QHD) in Hebei Province, Rizhao (RZ) in Shandong Province, Lyusi (LS) in Jiangsu Province, and Beihai (BH) in Guangxi Province. Comparisons of 199 alleles among the five populations showed that, in the fourteen loci, polymorphism information content (PIC)values ranged from 0.696 to 0.853 with high polymorphism. The number of alleles ranged from 8 to 22 and the average number () of alleles were 14.2 and 11.05, respectively. Expected () ranged 0.769–0.826 and 0.809–0.858, respectively, suggesting high levels of genetic diversity in all populations. Only the locus in the DD population deviated significantly from Hardy-Weinberg equilibrium, further indicating stability in the genetic diversity of all populations. The genetic distance among the five populations ranged from 0.141 2 to 0.340 9, with minimum and maximum distances between DD and QHD and between DD and BH, respectively. The UPGMA tree indicated highest similarity among geographically close populations, clustering DD with QHD and RZ with LS, the structure of which was confirmed by Bayesian cluster analysis. The were 0.039 1– 0.094 7, suggesting a moderate degree of differentiation among the five wild populations. Overall, the results suggest a high level of genetic diversity and differentiation among five grand jackknife clam populations from geographically distinct locations along the coast of China. Precaution should be taken to protect the germplasm of this species, particularly when designing stock enhancement programs.

Abstract:fish, and used to be an important object for bottom trawl, bottom gillnet fishing in South China Sea. Due to the degradation of habitats and overfishing, the quantity of this fish has been decreased greatly in recent years. The recent studies on mainly focused on the chromosome, fisheries resources survey as well as phylogenetic relationship for terapontid fish based on gene and 16S RNA , there is no genetic investigation reported. In the present study, the control region of mtDNA of 80 individuals of 5 populations collected from Jieshi, Yangjiang, Linggao and Lingshui, were sequenced to analyze genetic variation in South China Sea, of which 42 mutations and 60 haplotypes were detected in the 951bp sequences. Overall haplotype diversity and nucleotide diversity were relatively low (=0.009±0.000), of which the nucleotide diversity () of Lingshui population is the highest (0.010), and Dongxing population is the lowest (0.008). Apart from 8 haplotypes shared by various populations, the remaining ones were endemic to each population. In the Kimura 2–parameter based neighbor-joining tree and parsimony network, haplotypes from various locations were intertwined together, and no deep lineage branches found, suggesting no obvious phylogenetic and geographical structure. Pairwise fixation indexes among 3 populations from mainland China coastal waters ranged from >0.05), and gene flow from 14.54 to 27.84.values between 2 populations from Hainan Island was >0.05), and gene flow was 5.68. However among the mainland coastal populations and Hainan Island populations ranged from 0.0616 to 0.135 3 (<0.05), gene flow were 1.868 63.808 4, indicating that there were no obvious genetic differentiation within the mainland coastal groups and within Hainan Island groups, but there were medium but statistically significant genetic differentiation between the mainland coastal populations and Hainan Island populations( mainly lives in shallow waters, and juveniles often attach to floating weeds, which may be drifted away along currents. The high dispersal potential and the absence of obvious geographic barriers may cause genetic homogeneity within mainland group and within Hainan island group. However Qiongzhou Strait formed after the separation between the mainland and Hainan Island causes the general trend direction of the annual current from east to west in high strength, promoting the differentiated between the mainland group and Hainan island group, as such there are two management of protected units, Lingshui population were recommended to be protected in priority owing to its highest nucleotide diversity. The significant negative values of neutral test (Fu’s =<0.05), the unimodal mismatch distribution and atypical star-shaped distribution of haplotypes in the parsimony network all suggested a recent population expansion, and the deduced expansion time was 120.636.2 ka BP (i.e., during the late Pleistocene), effective population size after the expansion was about 8.7×10⁶ times larger than before, which probably related to fluctuated sea levels and temperature during the late Pleistocene epochs.

Abstract:in the north Yellow Sea was estimated using Bayesian methods. The relationship was calculated for both the assumption of an additive error structure and for a multiplicative error structure. The species form factor was calculated according to estimated parameters from this study and those found in the literature. Samples were obtained from the commercial catch of trawls at Weihai Port and Shidao Port and of set nets in Shuangdao Bay in Shandong. Bayesian methods effectively estimated parameters of the weight–length relationship and their uncertainties. The deviance information criterion selected the weight–length relationship with multiplicative error structure as the best model from the candidate models. The weight–length relationships of Japanese anchovy in spring, autumn, and winter were 3.1774, and, respectively. There were significant differences among the seasonal curves of the weight–length relationship. The springtime curve was located above those of autumn and winter, while the autumnal curve was similar to that of winter. Thus, the relationship for pooled data across seasons would underestimate the weight in spring and overestimate autumn and winter weights. Parameter showed an increasing trend since 2004, where estimated values between 2004 and 2014 were distinctly larger than those prior to 2004. The weight–length curves since the late 1990s were located above those from the 1960s to the1980s, implying the mean weight for a given size fish had increased. The total length–fork length (TL–FL) relationship of Japanese anchovy in the north Yellow Sea was TL=0.0615+1.0909FL. The form factor of Japanese anchovy ranged from 0.004 73 to 0.006 60 (median=0.006 03), which could serve as an index for the characteristic shape of Japanese anchovy. Thus, this study provided basic parameters needed to evaluate Japanese anchovy stocks and to further investigate the response mechanism of Japanese anchovy to fishing pressure and environmental changes.

Abstract:Zooplankton species composition, dominant species, and average biomass and abundance were compared between samples taken in the Minjiang River and Jiaojiang River estuaries in September 2008 and August 2010, respectively. The contribution of the dominant species to the total abundance was also determined. Diffe- rences in the zooplankton of the two estuaries were evaluated with respect to each estuary’s water mass properties, and the bait characteristics and value of the fishery of the two areas were also compared. The results indicated that the zooplankton species composition of the Jiaojiang estuary fishing grounds was of higher quality than that of the Minjiang estuary. The Jiaojiang estuary had larger Copepodaand also contained the genera Mysidacea, Pteropoda, and Amphipoda, which the Minjiang estuary lacked. Strong summertime upwelling and run-off created nutrient-rich conditions in the Jiaojiang estuary that supported large zooplankton communities with an average abundance of 281.17 ind. The warm temperate species was most dominant, averaging 121.19 ind.The waters of the Minjiang estuary were lower in nutrients because the estuary was influenced by the nutrient-poor Taiwan Warm Current in summer. Average zooplankton abundance in the Minjiang estuary was 110.19indEvadneter gestina, the most dominant species, averaging 45.63ind.The Jiaojiang estuary surpassed the Minjiang estuary in species composition, zooplankton abundance, and overall quality of its fishing grounds. Comparison between the quantitative characteristics of the zooplankton and water masses of the Minjiang and Jiaojiang estuaries indicated general differences between the fishing grounds and larger migrant fish populations in the Jiaojiang estuary.

Abstract:The surf zone is an important habitat for larval organisms; in particular, a large amount of research has de- monstrated the utility of the surf zone as a nursery ground for various fish species. In last decade, concerns have arisen in China about this habitat, particularly around the Yangtze River estuary. Species composition, habitat selection, and biodiversity have been previously investigated. This study analyzed the characteristics of the larval fish assemblage in the surf zones of the Yangtze River estuary and Hangzhou Bay and determined the relative influences of various abiotic factors. Fish larvae were collected monthly using a small trawl net (1 m×4 m, 1-mm mesh size) at 12 stations during each spring tide from August 2009 to August 2010. Temperature, salinity, distance from the outermost site (km), landform, and substratum were simultaneously recorded at each sampling site. All collected specimens were fixed in 5% formalin, after which they were identified to the lowest possible taxonomic division and measured (length, mm). In total, 14907 individuals were caught by 462 hauls. The dominant species were (11.58%), Eleutheronema rhadinum (5.62%). Hierarchical clustering grouped the 13 months of sampling into 4 significant clusters(December–April, May, June–September, and October–November), showing clear species replacement among groups. The twelve stations were grouped into 2 groups: the Yangtze River estuary group (ST1–ST7) and the Hangzhou Bay group (ST8–ST12). SIMPER analysis indicated that the species contributing most to dissimilarity among groups were (>10%), indicating differentiation in habitat selection. Canonical correspondence analysis was performed on the same dissimilarity matrices. Salinity and temperature were significantly related to the distribution of larval and juvenile fishes, but did not significantly explain the total distribution, suggesting latent factors are influencing the assemblage. Generalized additive models were conducted for each primary species to reveal individual influencing environmental factors. The abundance of spp. were positively related to high temperature and sand substrata, while spp. were positively related only to high temperature. Two species in the genus P. japonica and were also positively related to sand substrata. In conclusion, this study revealed that temperature and salinity significantly affected spatiotemporal variation of the entire larval fish assemblages in the surf zones of the Yangtze River estuary and Hangzhou Bay, while substrata and landform had varying influence that differed among species. Habitats with sandy sediment and an open landform may be preferable to most larval fishes in the Yangtze River and Hangzhou Bay surf zones.

Abstract:is a dominant species in the fish assemblage of the Yellow River estuary and adjacent waters and is important in the estuarine ecosystem and the local fishery. Sustainable exploitation and fishery management of this species requires knowledge of its spatiotemporal distribution and the influencing environmental factors. Bottom trawl surveys were conducted and environmental factors including sea bottom temperature (SBT), sea bottom salinity (SBS), and depth were concurrently measured in June, August, and October of 2013 and in February, April, and May of 2014. A generalized additive model (GAM) was used to examine the spatial and temporal patterns of distribution of and the relationship between its abundance and spatiotemporal variation in environmental factors. was found to mainly inhabit waters north of 37.80°N and west of 119.00°E. The spatial distribution of differed distinctly among months. In June, August, and October of 2013, the goby was mainly distributed in inshore areas of the Yellow River estuary, while abundance was higher in offshore waters in February 2014.The average abundance as catch per haul per hour varied monthly. At 862 g/h, abundance was highest in August, followed by June with 521 g/h, and abundance was lowest in May. The environmental variables explained 34.8% of the variation in abundance of , and sea bottom temperature and salinity significantly influenced the spatiotemporal distribution. GAM indicated that the abundance of was high when bottom temperature was 17–22; thus temperature was a major factor driving patterns of distribution and abundance of . Abundance was highest in areas with salinity of 18–27 ppt where marine and fresh waters mixed. Abundances were low in offshore waters with high salinity and in low salinity estuarine waters. The abundance of was not correlated with depth, likely because of the relatively shallow waters in the Yellow River estuary and the limited survey region. Water temperature and salinity in the Yellow River estuary showed large spatiotemporal variation, and appeared well adapted to the environmental variation.

Abstract:The selectivities of 30 mm diamond mesh codend (30D) and square mesh codends with mesh sizes of 20 mm (20S), 30 mm (30S), and 40 mm (40S) were studied using the parallel haul method and a logistic curve on the coast of Zhaitang Island, Qingdao, in spring 2014. Diamond codend of 16 mm (2Multivariate statistics and the maximum likelihood method indicated that all experimental codends were effective in releasing of some economic fish species relative to the control net. Square mesh codends showed better selectivity than diamond mesh codends. The for 30S were 4.61% and 16.80% higher than those for 30D, and the 50% retention body length ( 38.47% and 61.29%Comparison with catch data using square mesh codends showed that the was 6.58 cm and 7.20 cm, and the selection rage (SR) was 3.02 cm and 0.87 cmof was 2.88 cm, 4.03 cm and 10.49 cm, and the SR was 0.74 cm, 0.52 cm and 2.67 cm for the 20S, 30S and 40S, respectively. Thus, t increased with larger square codend mesh size. A comprehensive analysis of the effects of different mesh types on the economic value of the catch, the release ratio of low economic value captures, and labor input of sorting catches all suggest that the use of 30 mm square mesh codend the fishery by reducing unwanted bycatch and therefore should be implemented in the region.

Abstract:Haizhou Bay is an important spawning, nursery, and feeding ground for many commercially important fishery species. In recent years, many commercial fish populations have declined in abundance because of overfishing, climate change, environmental pollution, and multiple other factors. plays an important role in the food web of the Haizhou Bay ecosystem. Thus, management of a an understanding of the relevant environmental factors. To determine spatio-temporal variation in the distribution and abundance of , bottom trawl surveys were conducted in March, May, July, September, and December 2011 in Haizhou Bay. The relationships between patterns of distribution and environmental factors were analyzed using generalized additive models (GAM). Abundance of exhibited distinct seasonal and spatial variation, with abundance highest in July and lowest in September. was primarily distributed in the northeastern part of Haizhou Bay, which is the cold center of the southwestern Yellow Sea, suggesting a strong influence of the Yellow Sea Cold Water Mass on distribution patterns. GAM analysis also showed that month, depth, and distance from shore significantly influenced the distribution, where abundance increased with depth and distance from shore. The abundance of was highest in the waters 14–36 m deep and roughly 70 km from the coast, which may relate to the reproductive migration of

Abstract:The stock enhancement program in Laoshan Bay is vital for the Yellow Sea fisheries, and it is essential tounderstand the ecology of the release areas. The springtime species composition and diversity of the Laoshan Bay fishassemblage were determined using bottom trawl surveys conducted in May 2014. The catch included a total of 32 fishspecies in 8 orders, 21 families, and 30 genera. Perciformes were the most abundant, where Gobiidae and Sciaenidaeaccounted for 36.87% and 36.87% of total catch biomass, respectively. The index of relative importance indicated 3dominant fish speciesChaeturichthys stigmatiasHexagrammos otakii, were the next six main species and accounted for 31.98% of total catch biomass. Diversitycalculated as the Margalef species richness index, Shannon-Wiener diversity index, and Pielou evenness index were3.19, 2.34, and 0.68, respectively, which were similar to those of Laizhou Bay, Jiaozhou Bay, and Haizhou Bay, althoughspecies numbers were smaller. Thus, the nine most abundant species accounted for 83.52% of total catch biomassand were also considered important for trophic relationships in the Laoshan Bay springtime fish assemblage.Stomach content analysis indicated three feeding types in the primary species, where was a zooplankivore, and the other six species were benthivores.Benthivorous fish were most abundant, accounting for 57.38% of total catch biomass. The average trophic level of thefish assemblage was 3.52, and the main food species were

Abstract: are bioresources important for a wide range of applications in aquaculture, environmental treatment, medicine, agriculture and industry. For instance, Skeletonema costatum have served as natural feed of aquatic animals; have been widely used to their high content of carotenoids. Although more than 0.2 million species exist on earth, only a very small proportion of microalgae have been exploited. In China, approximately 600 microalgal species have been identified, of them less than 10 species have been cultured on large-scales so far. Isolation and identification of more strains from natural environments is thus foundamental and always appreciated by researching and exploiting communities. Yellow Sea and Bohai Sea are rich in phytoplankton and deemed to be an important microalgal repository. However, the reports on the isolation and cultivation of microalgae inhabiting these sea areas are very scarce. In order to promote the exploitation of microalgal resource in Yellow Sea and Bohai Sea, a surveying cruise was carried out in summer 2011, during which the diversity of net collected microalgae was determined. Moreover, a rich collection of cultivable microalgal strains were successfully isolated from 71 stations. A total of 44 species in 30 genera, 4 phyla, were identified in fixed summer seawaters. Among them, Bacillariophytas (28 species in 20 genera) accounted for 51.8%; while dinophytas (14 species in 8 genera) accounted for 23.2%. One speceis in phylum Chrysophyta (Coscinodiscus sp. and which appeared in almost all stations were dominant species. In total, 92 microalgal strains were isolated and purified with diverse methods including capillary catching, streak plating and serial diluting, alone or in combination. Molecular systematic analysis identified the isolated as 19 species including 9 bacillariophytas, 3 phaeophytas, 3 heterokontaes, 2 chlorophytas, 1 dinophytas and 1 haptophyte. The isolated species were mainly small in size, of them 9 in chlorophyta, phaeophyta, heterokonatae and haptophyte were in pico-size, and 10 in bacillariophyta and dinophyta were in nano-size. Among all isolated strains, those in genera Nannochloropsis were expected to be important for EPA production due to their high EPA content; 7 chlorophytas may serve as the candidates for biodiesel production; and 8 Bicosoecales in heterokontae promised for high biomass production therough fermentation and further environmental pollution bioremediation. In spite of the abundance of microalgae in Yellow Sea and Bohai Sea, almost all species we fixed and identified by morphology were difficult to cultivate. sp. (in nano-size) were the only two species observed in fixed seawater and survived laboratory culture. Although the algae in micro-size, , accounted for a large portion in fixed samples, they were unable to survive laboratory culture. Technical means need further optimization in order to get as many cultivable microalgae as possible. We found that distribution of cultivable microalgae is wide in seawaters. Bacillariophytas spread the whole area, and centralized in Laizhou Bay; while the harmful nutriments rich thus facing the risk of red tide. Chlorophytas and haptophyte were mainly collected from north Yellow Sea, a few chlorophytas also collected around Port of Tongxhan. Most phaeophytas were collected from the coasts of and Liaodong Peninsula. Most heterokontaes were collected from north Yellow Sea. In additon, it was the first report that inhabits Chinese coastal seawater.

Abstract:) is one of the largest single biological resources on the earth, its largebiomass and potential to support a large fishery has received increasing attentions of many countries. China began to be involved in the Antarctic krill fishery in 2009 when two large scale factory trawlers from Chinese fishing enterprisers went down to the Southern Ocean for exploratory fishing. At the beginning, large mesh size trawl net redesigned based on Chilean Jack Mackerel trawl was used, and the fishing efficiency was not satisfactory due to poor match between the net and the trawl doors, consequently the catch was much lower than those of Norway, Korea and Japan fishing fleets. In 2010, Chinese fishing vessel introduced 192.60 m×110.50 m krill trawl, a small mesh size specialized krill trawl from Korea, and fishing operation indicated that catch was also not satisfactory because of the limitation of the opening of net mouth. This was changed in 2012 when Liaoning Province Dalian Ocean Fishery Group of Corporations introduced the specialized krill trawler “Fu Rong Hai” from Japan and used the Japanese krill trawl ( m small mesh size krill trawl) on board the fishing vessel, and the catch increased greatly. This study analyzes the performance of the two krill trawl nets described above, i.e., Korean krill trawl (referred to as Net B) and the Japanese krill trawl (referred to as Net A) by carrying out model experiment based on the Tauti’s law. Large scale ratio λ of the model net was chosen as 14 and 16, respectively, for Nets A and B. The average small scale ratio of the model net was 3; the ratio of towing speed between the full scale and the model net was 3. Model experiments were conducted in the towing tank of the East China Sea Fisheries Research Institute. The towing speeds of the model net ranged from 0.345 m/s to 0.685 m/s with the interval 0.085m/s (equivalent to 2.0–4.0 kn with the interval of 0.5 kn for the full scale net). The ratio of the distance between two lower wing ends to lead line length () ranged from 0.4–0.55 with the interval of 0.05. During the model experiment, drag and net mouth height at varied towing speed and level were recorded, and the drag, mouth height and energy consumption coefficient of the prototype net were recorded at corresponding towing speeds according to model conversion rules and the hydrodynamic performance of the net was analyzed. The results indicate: (1) the drag of Korean krill trawl (192.60 m×110.50 m, Net B) was lower than that of Japanese krill trawl (185.40 m×128.50 m, Net A); (2) Japanese krill trawl was superior to Korean net in opening performance (net mouth height, swept area), economical efficiency (energy consumption coefficient) and filtration (hydrodynamic performance); (3) the net mouth and net body of both model nets remained stable in the water during the tank tests, and body of nets was when towed in the tank; (4) the drag of full-scale trawls could be calculated as:0.24R_e^-0.5for Japanese krill trawl (Net A),0.177R_e^-0.54for Korean krill trawl (Net B) ande^-0.52for the combination of the above two trawls .

Abstract:Ocean acidification and eutrophication are two prominent problems that affect marine ecosystems in manyaspects. Ocean acidification affects a series of physiological activities of macroalgae, which serve as important primaryproducers in marine ecosystems with regard to growth, photosynthetic carbon, and nutrient absorption. Moreover, it isglobally acknowledged that seaweed cultivation is an effective way to ease the pressure of offshore eutrophication. (Rhodophyta, Rhodophyceae, Florideophycidae, Gigartinales, Gracilariaceae) is distributed inwarm water along the coast of Zhejiang and Fujian Provinces. It grows in stone bogs in the intertidal zone, andsandstone and shells in the subtidal zone. –40 cm long with a rufous color andcylindrical fronds. The ecological effects of has been used toimprove pond water quality, because it absorbs N and P when it is growing. Moreover, it shows high economic value asboth raw agar material and abalone feed. The majority of research on has been about pond cultivationtechniques, growth, uptake of nutrient and biochemical composition, and ultrastructure of vegetative cells. However,there are few reports on the interaction effects of C and N on its eco-physiological characteristics. This studyinvestigated the growth and biochemical composition of in response to different C sources (a model of oceanacidification) and N sources (a model of eutrophication). was exposed to two C concentrations of 800 (enhanced) and 400 (as control),and four N concentrations of 100 μ-N (enhanced), and 10-N (as the control), with three replicates for each group. The culture density of was 1 g/L. Thealgae were cultured under 100 s) illuminated by incandescent tubes for 12L : 12D photoperiod at 20.The culture seawater was continuously aerated and renewed every 2 days. Differences in seaweed growth, soluble sugar(SS), soluble protein (SP), phycoerythrin (PE), chlorophyll a (Chla), total nitrogen (TC), and total carbon (TN)were measured 10 days after being exposure to different conditions. The results indicated that enhanced C and Nwere proposed to increase seaweed growth, and the special growth rate reached its peak (11.70%/d) in the 800 and 100 -N treatments. Moreover, high COlevels induced decrease of SP, PE, and Chla contents,whereas SS content increased. With density increase of NaNO, PE and SP gradually increased, SS gradually reduced,and Chla had no significant change (growth and directly affects its physiological and biochemical characteristics. The growth rate of can be considered a suitable bioremediation speciesfor artificial culture in regions that experience eutrophication.