• Volume 41,Issue 12,2017 Table of Contents
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    • Effects of crystalline methionine and calcium 2-hydroxy-4-(methylthio) butyrate on growth, antioxidant ability and intestinal protease activities of Japanese seabass (Lateolabrax japonicus)

      2017, 41(12):1908-1918. DOI: 10.11964/jfc.20161210663

      Abstract (1528) HTML (487) PDF 618.50 K (1521) Comment (0) Favorites

      Abstract:To investigate the bioavailability and requirement of methionine, this experiment was conducted to study the effects of DL-methionine (DLM) or calcium 2-hydroxy-4-(methylthio) butyrate (MHA) on growth, antioxidant and intestinal protease activities of Japanese seabass (Lateolabrax japonicus). Fish [initial body weight: (5.67±0.05) g] were fed one of nine experimental diets containing 0%, 0.2%, 0.4%, 0.6% or 0.8% exogenous methionine (control, MHA 0.2, MHA 0.4, MHA 0.6, MHA 0.8, DLM 0.2, DLM 0.4, DLM 0.6 and DLM 0.8) for 8 weeks. After the feeding experiments, growth performance, body composition,antioxidant, intestinal protease and blood biochemistry were determined. The results showed that weight gain ratio (WGR) and specific growth rate (SGR) were significantly affected by dietary methionine level and source. Weight gain ratio increased with increasing level of DLM and MHA from 0% to 0.6% and then decreased. Moreover, weight gain of fish fed with MHA diet was higher than that of fish fed with diet contained the same DLM level. Dietary methionine level could significantly affect feed conversion ratio (FCR) and whole-body composition of fish. FCR and crude lipid content decreased and then increased with methionine levels increasing. The opposite is true for crude protein. In addition, superoxide dismutase activity was decreased in the methionine group than that in the control group. The activities of catalase and glutathione reductase in liver also increased and then decreased as methionine levels increased, but the contents of glutathione and malondialdehyde were just opposite. Serum alanine transaminase levels decreased and then increased with the increase of methionine levels. Cholesterol and triacylglycerol, aspartate aminotransferase activities decreased in the methionine group than that in the control group. Lysozyme activity was significantly higher in the methionine group than that in the control group. The activity of intestinal protease increased as DLM and MHA increased from 0% to 0.6% and then decreased with further increases of methionine levels. In conclusion, the optimal level of dietary MHA or DLM supplement for seabass was estimated at 0.6% on the basis of WGR and SGR. Based on the second-order regression analysis of SGR, the optimal methionine for seabass was 1.57%. The bioavailability of MHA was higher than that of DLM (134.15%). The supplement of DLM or MHA could improve the hepatic antioxidant ability of fish, which would benefit the health of liver.

    • The family line establishment of the hybrid Epinephelus moara (♀) ×E. lanceolatus () by using cryopreserved sperm and the related genetic effect analysis

      2017, 41(12):1817-1828. DOI: 10.11964/jfc.20161210630

      Abstract (1733) HTML (509) PDF 548.36 K (1729) Comment (0) Favorites

      Abstract:Hybridization is a way to establish a new gene combination and important genetic progress, through which various desirable traits can be combined to improve varieties. In this study, eggs from 27 females of Epinephelus moara were fertilized with cryopreserved sperm from 4 males of E. lanceolatus, and 28 paternal half-sib families were constructed. At 130d post-hatch, 5 traits including full length, body length, head length, body height and body weight, were measured in 1294 fries from all the families and analyzed by using One-Way ANOVA. Maternal or paternal genetic effects were predicted by using mixed linear model. Variances of five traits were analyzed by using minimum norm quadratic unbiased estimator (MNQUE). Genetic correlation and heritability were analyzed by using “Additive-dominant” genetic model. Maternal and parental additive and dominant random genetic effects were predicted by using adjusted unbiased prediction (AUP). The results showed that significant or extremely significant differences existed in the additive, dominant, genetic and apparent genetic correlations among five traits. Narrow heritability of five traits ranged from 0.521±0.020 to 0.805±0.018, while broad-sense heritability ranged from 0.521±0.017 to 0.832±0.011. Five traits of seven female parents (5766, 6436, 5779, 5798, 5782, 6440, 5790) among 27 gained extremely significant positive additive effect, and one male parent ( 8920)among four gained extremely significant positive additive effect. Growth indexes in their offspring were significantly higher than those in other families. Growth indexes of head length, body height and body weight among seven hybrid combinations (5766*5777, 6436*8932, 5779*8932, 5798*8932, 5782*8932, 6440*8920, 5790*8920) among 28 gained significant or extremely significant positive dominant effect. This was the first study to take distant hybridization between E. moara and E. lanceolatus by using cryopreserved sperm and to predict their genetic effects, which provided solid scientific basis for the development of distant hybridization techniques and new variety breeding in groupers.

    • Recombinant expression and polyclonal antibody preparation of the nucleoprotein, phosphoprotein and matrix protein of spring viremia of carp virus

      2017, 41(12):1919-1927. DOI: 10.11964/jfc.20170110679

      Abstract (1689) HTML (535) PDF 1.56 M (1448) Comment (0) Favorites

      Abstract:Spring viremia of carp virus (SVCV) is an OIE listed highly pathogenic agent of several economically important Cyprinidae fish species. Currently, there is no effective vaccine or drug available for this virus, and prevention of SVC mostly relies on prompt diagnosis. Previously, detection methods based on the G gene or the G glycoprotein have been developed. However, the highly genetic diversity of the G gene seriously limits the reliability of those methods. To develop a rapid immunological detection method for SVCV, the N, P and M genes of SVCV were cloned into a pRSET-A prokaryotic expression vector. Recombinant proteins were then induced with 1 mmol/L IPTG at 37 ℃. Next, recombinant proteins were purified and used to immunize New Zealand rabbits. Titers and specificities of antibodies were verified by indirect ELISA and Western blot. Our results indicated the obtained antibodies were highly specific to SVCV and the titers could reach at least as high as 204 800. Besides, indirect ELISA assays based on prepared antibodies showed there was no cross reaction with other aquatic viruses. Our results will be useful for the rapid immunological detection of SVCV and provide a new insight into the vaccine development of SVCV.

    • Real-time PCR detection of Aeromonas salmonicida by amplification of specific vapA gene

      2017, 41(12):1928-1935. DOI: 10.11964/jfc.20161110608

      Abstract (1667) HTML (522) PDF 1011.52 K (1568) Comment (0) Favorites

      Abstract:In order to implement the early and quick quantitative determination of Aeromonas salmonicida, a SYBR Green I Real-time PCR method of A. salmonicida was established based on the pathogen sequence information. Based on the vapA of virulence array protein gene sequence of A. salmonicida, a pair of primers was designed and used in a real time quantitative polymerase chain reaction (qPCR) assay. The specificity, sensitivity, repeatability and application of the system were also evaluated. The results showed that A. salmonicida and its subspecies can be clearly discriminated from the other 10 bacteria species by SYBR Green I Real-time qPCR, which indicated that the primer pair has good inter-species specificity. The standard curve established by recombinant plasmid showed a fine linear relationship between initial templates and threshold cycle, which can be described as y=-4.8345x+42.535 (R2=0.998). The sensitivity analysis showed that the detection limit was 34 copies/μL, which suggested that the sensitivity of Real-time qPCR was about 1000 times higher than that of the conventional PCR assay. The established method was applied to detect the samples in rainbow trout after artificial infection. Results showed that 15 of those samples were positive, which had complete agreement (100%) with bacteriological analysis by isolation and culture. In conclusion, the developed Real-time PCR assay for A. salmonicida is fast, highly specific, and sensitive. This method had a broad application for clinical diagnosis and disease surveillance in aquaculture.

    • Cloning and functional analysis of an immune-induced promoter in common carp (Cyprinus carpio)

      2017, 41(12):1829-1837. DOI: 10.11964/jfc.20160810515

      Abstract (1527) HTML (792) PDF 846.52 K (1628) Comment (0) Favorites

      Abstract:The study aimed to explore a teleost promoter applicable to genetic engineering breeding for disease resistance. The expression pattern of Ras-associated binding-GTPases 1a3 (Rab1a3) gene in common carp (Cyprinus carpio) was analyzed by quantitative real time PCR experiments. The transcription level of Rab1a3 gene was high in tissues closely related to immune defense, including gill and head kidney, while the transcription was enhanced after immune stimulation. This transcription pattern well fitted the conceived perfect expression pattern of heterologous immune gene in transgenic fish. Bacterial Artificial Chromosome (BAC) library of common carp was screened by PCR, using Rab1a3 specific primers. A BAC clone containing Rab1a3 gene was found and then sequenced, to obtain the complete genomic sequence of Rab1a3 gene, including its upstream and downstream regulatory sequences. A putative 1014 bp promoter of Rab1a3 gene, with multiple binding sites of immune related transcription factors, was predicted using several bioinformatics tools, while TATA box and CpG islands of typical promoters were absent. The promoter activity was verified in Ctenopharyngodon idella kidney cell lines, indicating that transcription of both green fluorescent protein (GFP) and firefly luciferase genes was able to be initiated by the 1014 bp fragment. After immune stimulation, the promoter activity reached 8.67 times as compared with before, determined by dual luciferase reporter assay. These results suggested that C. carpio Rab1a3 promoter could be a potential transgenic element with immune inducible characteristics, which initiates transcription of heterologous immune gene against exogenous infection in proper expression pattern, avoiding excessive transcription in unnecessary conditions.

    • Effects of short term addition of aflatoxin B1(AFB1) on the intestinal mucosal barrier of Litopenaeus vannamei

      2017, 41(12):1936-1945. DOI: 10.11964/jfc.20161010594

      Abstract (1488) HTML (487) PDF 2.94 M (1314) Comment (0) Favorites

      Abstract:In order to determine the impact of aflatoxin B1(AFB1) on the intestinal mucosa of Litopenaeus vannamei, shrimps were fed with normal diet and diet containing 15 mg/kg of AFB1 for 12 days, and the tissues of intestine were collected on the day 2, 4, 8 and day 12 of the experiment. The relative expression of genes in mTOR signal pathway including eif4ebp, eif4e1a, eif4e2 and p70s6k, the immune-related genes including Dorsal, Relish and proPO and mucin-like PM gene were quantified with RT-qPCR. The changes of intestinal morphology were explored under microscope. The results showed that, the expression of genes in mTOR signal pathway was affected by AFB1, eif4ebp gene was up-regulated from the 2 nd day, and decreased after reaching its peak on the 8th day; eif4e2 and eif4e1a genes were both inhibited on the 8th and 12th day; p70s6k gene was down-regulated from the 2rd to 8th day, and climbed to the initial level on the day 12. The immune response of the intestine was also stimulated by AFB1, Dorsal and Relish genes were induced significantly after fed with AFB1; proPO gene was up-regulated on the day 4 and day 8, followed by a fall to the initial level on the day 12; and the mucin-like PM gene was also significantly induced on the day 2, 4 and day 8. The morphology of shrimp gut was changed by AFB1, the nucleus of epithelial cells swelled, the clear margin of chromatin was no longer present, and the ecclasis of epithelial cell layer occurred. In conclusion, the function of intestinal mucosal barrier was affected by AFB1, not only the mechanical barrier was damaged, but also the chemical and immunologic barriers were impaired.

    • Analysis of genetic diversity in mass selection lines of white-shell Pacific oyster (Crassostrea gigas) using microsatellite fluorescent multiplex PCR technique

      2017, 41(12):1838-1846. DOI: 10.11964/jfc.20161110611

      Abstract (1633) HTML (673) PDF 570.03 K (1436) Comment (0) Favorites

      Abstract:To investigate the genetic variances in our successive selection strains for fast growth and white shell color of the Pacific oyster (Crassostrea gigas) during mass selection process, genetic diversity of three successive mass selection strains from G1 to G3, one based stock and two wild populations was analysed using multiplex assays with ten microsatellite markers. The study showed that the average allele number (Na) ranged from 7.2 to 12.6 and the mean allelic richness (Ar) ranged from 6.8 to 11.0, the expected heterozygosity (He) and observed heterozygosity (Ho) ranged from 0.672 to 0.769 and 0.486 to 0.542, respectively. Compared to wild populations, the three successive mass selection strains showed significantly lower in the mean number of alleles and the mean allelic richness, but there was no significant difference in the average expected heterozygosity among the populations. There were 39 cases deviating significantly from Hardy-Weinberg equilibrium among the 60 population-locus cases (6 populations × 10 loci), and the inbreeding coefficient (Fis) ranged from 0.215 to 0.342. Fst values ranged from 0.005 to 0.076, showing low-moderate level genetic differentiation among the populations. The results suggest that the genetic variation has not been significantly affected by continuous mass selection and high genetic variability remains existing in the three successive selection strains, indicating that there is still potential for increased gains in future selective breeding programs.

    • Antioxidant and protective effect of flavonoids from Salicornia bigelovii against CCl4-induced acute hepatic injury in mice

      2017, 41(12):1946-1955. DOI: 10.11964/jfc.20161110612

      Abstract (1549) HTML (668) PDF 625.61 K (1389) Comment (0) Favorites

      Abstract:To investigate the antioxidant effects and the protective effects of the flavonoids from Salicornia bigelovii on CCl4-induced acute hepatic injury in mice, the scavenging DPPH, ABTS, hydroxyl free radicals and superoxide anion free radicals abilities of the flavonoids from S. bigelovii were studied to show its antioxidant ability in vitro. Mice with acute hepatic injury were simulated by intraperitoneal injecting CCl4. Before simulation, mice were administered with the flavonoids everyday at doses of 75, 150, 300 mg/(kg·d) for 8 days. After that, mice in each group were sacrificed to determine the indexes including the enzyme activity of ALT, AST, ALP in the serum and MDA, GSH, CAT, SOD in the hepatic tissue. Meanwhile, the pathological changes in the hepatic tissues of each group were determined. In the experimental concentration range, the flavonoids from S. bigelovii have a good effect on scavenging four free radicals. Compared with the simulation group, the level of serum ALT, AST, ALP and liver MDA in each dose decreased significantly, and levels of SOD, GSH rose. The level of liver CAT in high and middle dose group was higher than that in the simulation group significantly. The result of the tissue section after H.E staining showed that the damage of liver tissues in each dose had different degrees of improvement. S. bigelovii flavonois can obviously protect against CCl4-induced acute liver injury in mice, and the protective mechanism is related to the fact that flavonoids can enhance antioxidant capacity and relieve membrane lipid per-oxidation.

    • Genetic analysis of major economic traits in Pyropia yezoensis using double haploid population

      2017, 41(12):1847-1857. DOI: 10.11964/jfc.20161210641

      Abstract (1672) HTML (552) PDF 947.61 K (1431) Comment (0) Favorites

      Abstract:Genetic parameters of major economic traits and their relationships of gametophytic blades in Pyropia yezoensis are the foundation of molecular breeding. A double haploid (DH) population of 152 lines was developed from the heterozygous conchocelis of an intraspecific crossing of wild-type strain (Py-WT2, male parent) and red mutation strain (Py-HT, female parent). It was found that all 6 traits (L50, W50, FW50, SGR-L, SGR-W and SGR-FW) were quantitative traits when analyzed by one-sample Kolmogorov-Smirnov test. The means of 4 traits of DH population lines were between their parents, among which W50 was nearer to female parent, and FW50, SGR-L and SGR-FW were nearer to male parent. L50 and SGR-W showed transgressive inheritance, among which L50 was lower than low value parent (female), and SGR-W was higher than high value parent (female). Coefficient of variation of the 6 traits of DH population was between 21.11%–56.68%, which meant that they had intermediate variability. Highly significantly positive correlations were observed between L50 and W50, L50 and FW50, W50 and FW50, and between SGR-L and SGR-W, SGR-L and SGR-FW, SGR-W and SGR-FW. Heritability of L50, W50 and FW50 were 58.17%, 64.00% and 57.64%, respectively; and the number of genes controlling the 3 traits was 6.61, 12.63 and 8.09, respectively. The equation of the curve between heritability (y) and the number of genes (x) was y=0.2922x2-4.6533x+76.162 (R2=1). According to estimated coefficients of skewness and kurtosis of the 3 traits tested, gene interactions were found to be absent for L50 and FW50, respectively, and complementary interactions were observed in W50 and SGR-W respectively, and duplicate interactions were observed in SGR-L and SGR-FW respectively. The results indicated that L50 and FW50 could be selected at early generation by their high heritabilities, less controlling genes and no gene interactions, and indirect selection could be applied between L50, W50 and FW50 to improve breeding efficiency of P. yezoensis because of their high correlations between each other.

    • Construction and identification of invF gene deleted Yersinia ruckeri and its biological characteristics

      2017, 41(12):1858-1866. DOI: 10.11964/jfc.20170310731

      Abstract (1742) HTML (578) PDF 2.05 M (1492) Comment (0) Favorites

      Abstract:Yersinia ruckeri is a conditional pathogenic bacterium which has widespread pathogenicity. The most important virulence regulatory system of Y. ruckeri is its type III secretion system (T3SS), while invF gene is an important regulatory factor of the T3SS. In this study, we constructed an unmarked deletion mutant with invF gene missing of a Y. ruckeri SC09, a highly virulent strain isolated from Ictalurus punctatus, and studied its biological characteristics. In order to investigate the effects of invF and T3SS on the pathogenicity of Y. ruckeri, construction of homologous arm AC, upstream fragment A and downstream fragment C of invF gene, was combined in overlap extension PCR. Then the homologous arm AC was ligated with the pLP12 suicide vector to generate the plasmid pLP12-invF. The plasmid was transformed into E. coli DH5α λ pir cells and it was amplified. The pLP12-invF was extracted and transformed into E. coli β2163 by electroporation, designated pLP12-invF-β2163. Then the pLP12-invF was transferred into Y. ruckeri SC09 strain through conjugation. Using the chloramphenicol for screening of insertional mutants and the vmt gene with L-arabinose for counter selection of deletion mutants. The deletion mutants were confirmed by PCR and subsequent sequencing. Then we observed morphology of bacteria and colonies, identified biochemical characterization and measured growth curve of the deletion mutants and wild type.In this study, the Y. ruckeri SC09 strain invF gene has been successfully knockouted. The morphology of bacteria and colonies, biochemical characteristics of deletion mutants and wild type were similar, but the colony size of deletion mutants was smaller than wild type and the growth of deletion mutants was slower than that of wild type. The method of pLP12 suicide vector, a highly efficient conjugation system form E. coli β2163 and screening by the antibiotic coupled with counter selecting by vmt gene, can be a simple and efficient gene editing operation to deal with Y. ruckeri, in the absence of a significant effect on its basic biological characteristics. In conclusion, this research obtained the unmarked mutant genes with the missing invF successfully, which laid a foundation for the studies of the pathogenicity of Y. Ruckeri in the future.

    • Effects of salinity and pH on hatching and larval activity of Lateolabrax maculatus

      2017, 41(12):1867-1877. DOI: 10.11964/jfc.20161210662

      Abstract (1668) HTML (674) PDF 780.82 K (1401) Comment (0) Favorites

      Abstract:In order to set up a scientific basis for the suitable salinity and pH and promote early seed extension of Lateolabrax maculatus of northern China, in this study, we used different salinities (0, 15, 20, 25, 30, 35 and 40) and pH(5.5, 6.5, 7.5, 8.5 and 9.5)gradients to investigate the hatching rate and deformity rate of fertilized eggs, as well as the vitality after 10 days' starvation in spotted sea bass. Meanwhile, the survival rate (SR) and survival activity index (SAI) were measured for newly hatched larvae during starvation experiment. Finally, we studied the effects of low salinity (0), culture salinity (30) and high salinity (45) on the growth performance of juvenile spotted sea bass. The results showed that the optimum hatching salinity was ranging from 20 to 35, with the highest hatching rate appearing at 25. The optimum pH for hatchery was 6.5-7.5, and the highest hatching rate came at pH 6.5. The lowest hatching rate and the highest deformity rate were found at low-salinity of 15, however, the survival rate and activity of fish at salinity of 15 was significantly higher than that in 30 and 35 groups. We speculated that salinity 15 approached the isotonic point of body fluid in L. maculatus. At the isotonic point, energy consumption for osmotic regulation is saved for better survival and growth. The results will provide more detailed guidance for L. maculatus cultivation. During the starvation experiment, the survival rate of newly hatched larvae was the lowest when facing fresh water (salinity of 0) stress on the first day, while the survival rates of low salinity groups of 15 and 20 were significantly higher than those cultured in 30 group. The survival rate in salinity group of 20 declined relatively gently, and the survival rate on the 8th day is 12.66% (0% in the other groups). On the first day of starvation, the survival rate of each pH group was lower than 90%, and the maximum survival rate was 89.11% appearing at pH 6.5. Compared with the salinity treatment, the larvae were more sensitive to pH change, because the hatching rate and final survival rate were much lower than those of salinity treatment group. For the salinity treatment to juvenile spotted sea bass, salinity groups of 0 and 45 would have greater damage to them, and the salinity of 45 was the most significant, which should be the upper limit of seed salinity extension. While the culture salinity of 30 was relatively appropriate. The results of this study will provide a scientific basis for setting the suitable salinity and pH for the breeding and enhancing the hatching and the survival rate, as well as promoting early seed extension of spotted sea bass in northern China.

    • Effects of temperature and water velocity on pharmacokinetics and the expression CYP3A-27 of enrofloxacin in rainbow trout(Oncorhychus mykiss)

      2017, 41(12):1878-1887. DOI: 10.11964/jfc.20161010593

      Abstract (1489) HTML (529) PDF 737.67 K (1387) Comment (0) Favorites

      Abstract:The pharmacokinetics of drug in animal was influenced by different environmental factors. In order to explore the effect of temperature and water velocity on pharmacokinetics of drug in rainbow trout, three temperature (5 ℃, 10 ℃, 15 ℃) and three water velocity (8 cm/s, 16 cm/s 24 cm/s) were studied. The temperature and water velocity were controlled by the control system, samples were determined by high-performance liquid chromatography (HPLC). Results showed that at temperatures of 5 ℃, 10 ℃ and 15 ℃, Tmax was 8.67 h, 4.78 h and 2.39 h; T1/2α was 0.86 h, 0.80 h and 0.77 h; T1/2β was 49.18 h, 45.81 h and 38.35 h; AUC was 140.49 μg/(L·h), 130.4 μg/(L·h) and 112.78 μg/(L·h), respectively. Metabolism of enrofloxacin in rainbow trout showed: in a certain temperature range, the rate of drug absorption and distribution at higher temperature is greater than that at lower temperature; the time to peak was shorter at higher temperature. At water velocity of 8 cm/s, 16 cm/s and 24 cm/s, Tmax was 8.57 h, 6.03 h and 4.04 h; T1/2α was 5.47 h, 2.16 h and 0.27 h; T1/2β was 26.54 h, 6.93 h and 2.13 h; T1/2ka was 7.68 h, 5.00 h and 2.01 h. The rate of drug absorption and distribution at higher water velocity is greater than that at lower water velocity; the time to peak was shorter at higher water velocity. In conclusion, the results from the present study indicated that in a certain range, the increase of temperature and water velocity improved the rate of drug absorption and distribution of enrofloxacin in rainbow trout.

    • Seasonal variations of spatial structure of Japanese squid (Loligo japonica) and octopus (Octopus ochellatus) in Haizhou Bay

      2017, 41(12):1888-1895. DOI: 10.11964/jfc.20161210635

      Abstract (2069) HTML (700) PDF 756.38 K (1567) Comment (0) Favorites

      Abstract:The cephalopod species, Japanese squid (Loligo japonica) and octopus (Octopus ochellatus) have important ecological and economic values in Haizhou Bay and adjacent waters. Japanese squid and octopus both spawn and nurse in the bay in early spring, and start overwintering migration from autumn. Their spatial structures vary substantially among seasons, driven by the seasonal variations of environmental changes and the monsoon climate. Studies of seasonal variations of their spatial structure contribute to understanding the distributional pattern and life-history of the two species. The spatial autocorrelation of sampling data has long been overlooked in the past. Besides, as most studies are limited by the scale of sampling time and spatial locations, the seasonal variations of spatial structure has been less studied. According to the survey data collected in spring (May), autumn (September) and winter (December) of 2011 using bottom trawls in Haizhou Bay and adjacent waters, we used multiple spatial analyses methods, including the global spatial autocorrelation, local spatial hot spots and semivariogram to examine the seasonal variations in the spatial structure of Japanese squid and octopus distribution. Our results show that the global spatial autocorrelation was weak for the two species, whereas there were strong local spatial aggregation distributions. The semivariogram analysis was consistent with global and local spatial autocorrelation, showing that the scale of spatial autocorrelation had seasonal changes of two species. The spatial structure of the two species was strong in spring and relatively weak in autumn and winter, and spatial autocorrelation in spring is more significant than that in autumn and winter. Both species showed a hot spot in the sea of 35.0°-35.5°N, 120.0°-121.0°E in spring, and there were non-cold spots area in the whole year. The spatial distribution showed non-aggregation or random pattern in the season when there was highest biomass density. The spatial distribution patterns of the two species may be related to seasonal environment changes as well as their feeding habits and the spawning and overwintering migration. This study contributes to a better understanding of the life-history traits and the distribution of suitable habitat for cephalopoda. The study provides research basis for scientific exploitation and management of the two species, which may benefit marine resources conservation and following studies.

    • Landmark-based morphometric identification of different geographical origins for the Chinese mitten crab (Eriocheir sinensis)

      2017, 41(12):1896-1907. DOI: 10.11964/jfc.20170210715

      Abstract (2030) HTML (537) PDF 1.85 M (1397) Comment (0) Favorites

      Abstract:Landmark-based morphometric analysis was conducted to identify variations in Chinese mitten crab Eriocheir sinensis from different well-known geographical origins around the same Changjiang River system, e.g., the Taihu Lake, Hongze Lake, Gaoyou Lake, Changdang Lake, Yangcheng Lake, Bacheng Aquaculture Water, Xinghua “Honggao” aquaculture area, and Chongming waters. Landmark coordinate values were extracted by image processing after digitalization of the carapace and the breastplate features, thereafter, processed with relative warp principal component methods, discrimination analysis, thin plate spline analysis and grid distortion. Many of the Type II landmarks were extracted by relative warp principal component analysis and they had important contributions (82.637%-97.698%) in explaining the most important variation. The discrimination analysis indicated that the carapace of male and female had exactitude distinguishing ratios of 100% while the breastplate had exactitude distinguishing ratios of 98.75% and 83.75%, respectively. All of these indicated that it was an effective method of habitat recognition of Chinese mitten crab by using landmark-based morphometric analysis, which provides some important reference and scientific basis for developing a more objective method for geographical origin identification of E. sinensis.

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