• Volume 37,Issue 6,2013 Table of Contents
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    • The cross breeding and genetic analysis of hybrids of Larimichthys crocea♀ and Nibea miichthioides♂

      2013, 37(6):801-808. DOI: 10.3724/SP.J.1231.2013.38438

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      Abstract:Abstract: To understand the feasibility of cross breeding between Larimichthys crocea ♀ and Nibea miichthioides ♂, two hybrid families were built (LN1 and LN2). Ploidy of F1 hybrids was identified. Moreover, ten microsatellite loci were used for genetic relationship analysis between F1 hybrids and their parents. The result showed that L. crocea (♀) and N. miichthioides (♂) can be successfully crossed and hybrid offsprings of normal survival were produced. Survival rate of hybrid offspring at the age of 45 days post hatch reached about 30%. However, fertilization rate (29.0%, 32.6%) and hatching rate (75.0%, 76.7%) of two hybrid families were significant lower than those in large yellow croaker families (P < 0.05). Appearance of juvenile hybrid fish is dramaticlly different from those of large yellow croaker, which has characteristic of both parents: slender body, sharp blunt head and their body sides are covered with black-brown spots. The results of DNA relative content investigation and genetic relationship analysis demonstrated that more than 90% of the hybrid offsprings were hybrid diploid, in addition, a small number of those were hybrid triploid and gynogenesis diploid. To the age of 45 days, growth rate of both hybrid diploid and hybrid triploid was slower than that in large yellow croaker. These findings will provide reference for exploitation and management of F1 hybrids of L. crocea (♀) and N. miichthioides (♂).

    • Effects of biofilms on settlement of plantigrades of the mussel Mytilus coruscus

      2013, 37(6):904-909. DOI: 10.3724/SP.J.1231.2013.38469

      Abstract (2735) HTML (0) PDF 1.30 M (2400) Comment (0) Favorites

      Abstract:The effect of biofilms developed in the aquariums on settlement of plantigrades of the mussel Mytilus coruscus was examined in the laboratory. Various aspects of biofilm biology were investigated including age, dry weight, chlorophyll a (chl a) content, bacterial and diatom densities. Bacterial community in biofilms was analyzed by the DGGE fingerprint technique. The correlation between the inducing activity of the biofilms and dry weight, bacterial and diatom densities, chl a content was also investigated. With the increase of biofilm age, dry weight, bacterial and diatom densities increased significantly and the maximum values were, respectively, 0.87 mg/cm2, 1.5 × 107cells/cm2 and 1.0 × 106 cells/cm2 after 28 d. Furthermore, these above three parameters were significantly correlated with biofilm age. Chl a content reached the maximum of 2.22 μg/cm2 after 14 d and no correlation between chl a content and biofilm age was observed. Plantigrades of M. coruscus preferred to settle on the biofilmed surfaces than the surfaces unfilmed. Overall the settlement of plantigrades on biofilms that formed in the aquariums increased with biofilm age, and the maximum of 76% settlement was obtained after 28 d. The enhanced settlement correlated to dry weight, bacterial density and diatom density, and their corresponding correlation coefficients were 0.717, 0.711 and 0.754. In contrast, there was no correlation between inducing activity of biofilms and chl a content. Moreover, shannon diversity index of bacteria community in DGGE profiles increased up to 28 d following immersion. The shift in bacterial community composition over time may be responsible for the higher settlement of plantigrades of M. coruscus on the older biofilms, indicating that bacterial community play an important role in the settlement of plantigrades in this species.

    • Path analysis of effects of morphometric attributes on body weight of Exopalaemon carinicauda

      2013, 37(6):809-815. DOI: 10.3724/SP.J.1231.2013.38465

      Abstract (2839) HTML (0) PDF 1.01 M (2364) Comment (0) Favorites

      Abstract:The effects of morphometric attributes on body weight of Exopalaemon carinicauda were analyzed by method of path analysis. Data of ten morphometric attributes, including the body length, total length, carapace length, carapace width, carapace height, first abdominal segment height, first abdominal segment width, abdomen length, number of upper frontal eminence spin and number of lower frontal eminence spin, were collected from 177 four-month-old E. carinicauda. The correlation coefficients among all attributes were calculated, and the path coefficients and determination coefficients were calculated in path analysis by taking the body weight as a dependent variable, and the other ten morphometric attributes as independent variables. Path analysis indicates that the path coefficients of four morphometric attributes (body length, carapace width, carapace height, first abdominal segment width) to body weight achieve significant difference (P<0.01) level. These attributes are significant factors determining body weight, among which body length weights the most (0.468**). While the direct effects of total length, carapace length, first abdominal segment height, abdomen length, number of upper frontal eminence spin and number of lower frontal eminence spin to body weight are quite small, therefore, they are the insignificant factors influencing the body weight and eliminated. The stepwise regression analysis establishes a multiple regression equation on the effects of body length, carapace width, carapace height, first abdominal segment width on body weight. The regression intercept and partial regression coefficients of the equation are -3.277, 0.470, 0.980, 0.528 and1.942. Judging from the high multiple-correlation coefficient (R2=0.976), the main attributes (body length, carapace width, carapace height, first abdominal segment width) determining the body weight have been selected.

    • Effects of Different Dietary Carbohydrates on Growth Performance and Metabolism Response of Juvenile Turbot Scophthalmus maximus

      2013, 37(6):910-919. DOI: 10.3724/SP.J.1231.2013.38575

      Abstract (2732) HTML (0) PDF 1.06 M (2692) Comment (0) Favorites

      Abstract:A study was conducted to evaluate the ability of juvenile turbot Scophthalmus maximus to utilize different molecular complexity of carbohydrates in diets. The control diet without carbohydrates supplementation contained 40% protein and 18% lipid. Based on it, 15% of three kinds of carbohydrate (glucose, sucrose and dextrin) were respectively added into the diet. At the same time, dietary lipid content was adjusted to 12% to keep isoenergetic with the control diet. Triplicate groups of fish (initial body weight: 8.12 ? 0.04 g) were hand-fed one of the four diets to apparent satiation for 9 weeks. The results showed that survival rate, daily feed intake (DFI), the apparent digestibility coefficients (ADCs) of protein and lipid, contents of moisture, crude protein, ash and glycogen in muscle, contents of moisture, crude protein and ash in liver, condition factor (CF) and plasma glucose were not significantly affected by dietary treatments (P > 0.05). Weight gain rate (WGR) and specific growth rate (SGR) of fish fed dietary dextrin and the control diet were significantly higher than those of fish fed dietary glucose and sucrose (P < 0.05). Feed efficiency (FE) of fish fed the control diet and dietary dextrin was significantly higher than those fed dietary sucrose (P < 0.05). However, there was no significant difference in FE between fish fed dietary glucose and the other three groups (P > 0.05). The order of the ADC of carbohydrate was glucose > dextrin > sucrose. The ADC of energy was significantly highest in fish fed dietary glucose and lowest in fish fed dietary sucrose (P < 0.05). Fish fed the control diet had the significantly highest lipid contents in muscle (P < 0.05), and there was no significant difference in lipid content of muscle among the other three groups (P > 0.05). The order of the liver lipid content was control > dextrin > glucose > sucrose (P < 0.05). The order of the liver glycogen was glucose > sucrose > dextrin > control (P < 0.05). Total amino acid concentration in plasma of fish fed the control diet was significantly higher than those fed dietary glucose and sucrose (P < 0.05). Plasma insulin of fish fed dietary dextrin was significantly higher than those fed the control diet (P < 0.05). Total cholesterol (CHO) in plasma of fish fed the control diet was the highest one followed by dietary dextrin. The lowest was found in fish fed dietary glucose and sucrose (P < 0.05). Triacylglycerols (TAGs) in plasma of fish fed the control and dietary dextrin were significantly higher than those fed dietary glucose and sucrose (P < 0.05). In conclusion, the present study suggested that turbot can utilize dextrin more efficiently than glucose and sucrose.

    • IDENTIFICATION OF TYPEⅠMICROSATELLITE MARKERS AND THEIR POLYMORPHISM IN Portunus trituberculatus

      2013, 37(6):816-822. DOI: 10.3724/SP.J.1231.2013.38343

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      Abstract:In the present study, typeⅠmicrosatellites of Portunus trituberculatus were screened from 13985 ESTs in the NCBI database by bioinformatics approach. A total of 287 type Ⅰ microsatellites were identified, among which 173 were the type of dinucleotide repeat being the most abundant microsatellite and accounting for 60.3% of the identified microsatellite markers, and 79 were the type of trinucleotide accounting for 27.5%, while hexa-, penta- and tetra-nucleotide repeats were rare. Among the dinucleotide repeats, AC/GT was the most abundant type with percentage of 53.8%, followed by the AG/CT type with 37.0%, while AT and GC were rare. 14 microsatellites were selected for polymorphism analyses, 8 of them showed polymorphism in a wild population of Portunus trituberculatus. The mean PIC and heterozygosity values were 0.57 and 0.63, respectively, among them, 6 PIC of microsatellites greater than 0.5, showing high polymorphism. This study showed that the way of screening typeⅠmicrosatellite markers from EST data was feasible. These typeⅠmicrosatellites can be used for further study in genetic diversity, genetic mapping and quantitative trait loci (QTLs) identification in Portunus trituberculatus.

    • A forecasting model for bacteroidal disease of cage cultured large yellow croaker (Pseudosciaena crocea) based on grey system theory

      2013, 37(6):920-926. DOI: 10.3724/SP.J.1231.2013.38427

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      Abstract:Based on the grey system theory, the occurring rule of the bacteroidal disease of cage cultured large yellow croaker (Pseudosciaena crocea) in Zhoushan was examined, and the relationship between the disease and environmental factors of surrounding sea waters was investigated. The grey models were established for forecasting the relevant data or incidence of the disease. The grey incidence analysis showed that the incidence of the disease was related to environmental factors in the different extent. Taking water temperature, the suspended solid, inorganic nitrogen and COD as forecasting factors, the GM(1,5), GM(1,4) and GM(1,3) were constructed respectively. Compared these models, the GM(1,3) constructed by inorganic nitrogen and COD had least mean relative simulation error. GM(1,1) was also established for the forecasting of the occurring data of the bacteroidal disease in wider scope, its veracity reached up to 90.5%.

    • Microsatellite-based consensus map of the Pacific oyster (Crassostrea gigas)

      2013, 37(6):823-829. DOI: 10.3724/SP.J.1231.2013.38423

      Abstract (2540) HTML (0) PDF 1.18 M (2056) Comment (0) Favorites

      Abstract:Linkage map is basic prerequisites for marker-assisted selection and map-based cloning. However, the number of co-dominant genetic markers on linkage maps published for the Pacific oyster (Crassostrea gigas) is still low. Microsatellite markers are inherited as co-dominant, which are reproducible and high polymorphism. They are easily transferred among populations and laboratories, and one of ideal joining markers to construct a consensus map. In order to improve the number of microsatellite markers, a consensus map of C. gigas was constructed based on common microsatellite markers among six mapping populations. The consensus map contained 161 microsatellite markers, spanning 10 linkage groups. The map length and average genetic distance is respectively 615.4 cM and 3.8 cM. The number of loci on linkage group ranged from 10 to 24 and the genetic length of linkage group varied from 47.3 to 73.3 cM. At present, this consensus map is the densest SSR-based map of C. gigas. Among different mapping populations, the grouping of markers is consistent; however, the order of markers is a little different, which likely attributed to polymorphism for chromosomal rearrangements in the natural population of Pacific oysters. The consensus map will provide a new reference tool for genetics and breeding of C. gigas in the future.

    • PCR detection and PFGE genotype analyses of streptococcal clinical isolates from tilapia in Guangxi

      2013, 37(6):927-935. DOI: 10.3724/SP.J.1231.2013.38506

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      Abstract:To acquire the data upon the clinical dominant strains of tilapia Streptococcus spp. and their genotype variations in Guangxi province, a total of 77 clinical Streptococcus spp. strains collected from the epdemic areas of Guangxi from 2006 to 2012 were identified by species-specific PCR. Among them, 37 strains collected from 2006 to 2011 were genotyped by the pulse field gel electrophoresis (PFGE) method. As a result, 57 out of 77 strains were identified as Streptococcus agalactiae, and the rests were determined as S. iniae by PCR identification process. As shown, the dominant stains from 2006 to 2007 were S. iniae, counting 94.7% (18/19), only 5.3% (1/19) was S. agalactiae strains. Between 2009 and 2012, the dominant strains, however, became to S. agalactiae, which counted 96.6% (56/58), only 3.4% (2/58) was referred as S. iniae strains. The strains were divided into two branches by PFGE genotyping. 20 S. iniae strains were in one classification with 4 PFGE genotypes, the similarities of which were 83.9~100%. 17 S. agalactiae strains were put in another branch with 5 PFGE genotypes, the similarities of which were between 47.4 and 100%. Our data confirmed that the prevalent strains of tilapia Streptococcus spp. in Guangxi province have been shifting from S. iniae (before 2008) to S. agalactiae (2009-2012), and the PFGE genetic diversities were demonstrated in the prevalent strains.

    • Molecular cloning and expression of Allograft Inflammatory Factor in Haliotis diversicolor under stresses

      2013, 37(6):830-839. DOI: 10.3724/SP.J.1231.2013.38463

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      Abstract:Allograft Inflammatory Factor-1(AIF-1)is a kind of calcium-binding protein with EF-hand domain. AIF-1 mRNA is robustly induced by IFN-γ in murine macrophages. It involves in transplant rejection, immune inflammatory reaction, non-inflammatory injury and so on. In this study, a molluscan AIF-1 gene, HdAIF-1, was cloned for the first time from Haliotis diversicolor. Its full-length cDNA sequence is 942 bp, with a 456 bp open reading frame encoding a protein of 151 aa. Quantitative real-time PCR results indicated that HdAIF-1 could be detected in all examined tissues, with the highest level in hemolymph and gill. Under thermal stress, HdAIF-1 was up-regulated in gill significantly at temperature-rise period and achieved the highest level when up to 31℃. However, the expression level of HdAIF-1 in hemolymph and hepatopancreas did not show significant difference between thermal group and control group from the first phase to the fourth, and its expression level was up-regulated significantly at 96 h in these two tissues. Under hypoxia stress, the expression level of HdAIF-1 in hemolymph was no significant difference between control and exposed groups. However, it was down-regulated at 24 h and up-regulated in 192 h remarkably in gill. After Vibrio parahaemolyticus challenge, the HdAIF-1 expression level achieved the highest level at the 3 h in hemolymph, reduced to the control level at 12 h, and then up-regulated significantly at both 24 h and 48 h. These results suggest that HdAIF-1 may play important roles as an immune factor under different stresses.

    • Histopathological Observation on Pseudotuberculosis of Seriola dumerili

      2013, 37(6):936-943. DOI: 10.3724/SP.J.1231.2013.38404

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      Abstract:Pseudotuberculosis is a bacterial septicaemia caused by Photobacterium damselae subsp. piscicida in several marine fish species.A similar Pseudotuberculosis of Seriola dumerili cultured in cage, broke out in Guangdong province, China. A lot of small typical whitish spots were observed in kidney and spleen of infected fish. The typical whitish spots were diffusely distributed in the whole kidney and spleen, both on the surface and section. These small whitish spots are about 1 millimeter in diameter. In order to diagnose the Seriola dumerili of suspected Pseudotuberculosis, the histopathologic changes of the infected fish and the morphology of the pasteurella picicida were observed under optic and electronic microscopy. A Gram-negative and rod-shaped bacterium was isolated from the spleen and kidney. The rod-shaped bacterium were dyed into dark blue in both end by Methylene blue.The size of the rod-shaped bacteria were approximately 0.8-2.6μm-long and 0.6-1.2μm-wide.The optical microscopy showed that not only scattered bacteria were observed in the blood,but also basophilic bacterial cluster-like structures were observed in the spleen and kidney. These bacterial cluster-like structures are about 1-2 millimetre in diameter. By squashing tissue of the kidney and spleen, there are large numbers of rod-shaped bacterium,which clustered into mission, or diffused distribution. Transmission electron microscopy showed that a small amount of bacteria were in macrophages and a large number of rod-shaped bacteria clustered into mission in the kidney and spleen.The bacterial clusters were surrounded by connective tissue. No virosome were observed in the infected organs by electron microscopy.According to the results above, the disease was diagnosed as Pseudotuberculosis. The main histopathologic changes of the other organs under optic microscope showed as follow: Denaturalization and necrosis were emerged in renal tubule epithelial cell, and lymphocytosis were in interrenal tissue. Number of macrophages in the renal interstitium.A large number of blood cells congested in renal interstitial, and there were basophilic rod-shaped bacteria and bacterial cluster-like structures in renal interstitial. Congestion,lymphocytosis and bacterial cluster-like structures were showed in spleen; Hepatocyte appeared fatty degeneration; The gill lamellar epithelial cells were swollen.Damage to heart included myocardial cell vacuolar degeneration, swelling, rupturing and necrosis; Damage to Intestinal epithelial cells were denaturalization, necrosis and inflammatory cell infiltration. Capillary of cerebral cortex and medulla were congestion. a small amount of nerve cell were degeneration and necrosis.

    • Histological and Immunohistochemical Observation on the Early Development of Head Kidney in Grass Carp (Ctenopharyngodon idellus)

      2013, 37(6):840-850. DOI: 10.3724/SP.J.1231.2013.38530

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      Abstract:Histogenesis of the head kidney was examined in the collected grass carp (Ctenopharyngodon idellus) from 1 to 103 days post hatching (dph). Histological technology was applied to learn the change of the structure of the head kidney and the changes in the distribution of IgM (Immunoglobulin M) positive cells and PAS (Periodic acid Schiff reaction) positive cells in head kidney. The primordium of the head kidney formed at 6dph. And in the primordium several undifferentiated hemopoietic stem cell spread among the renal tubules which derived from the protonephridia. Then, the immune cells increased gradually due to the hemopoietic stem cells’ differentiation from 7 dph to 16dph. Between 17 dph and 103 dph, the renal tubules degenerated gradually and the lymph and haematogenous tissue sustained by the reticulo-endothelial system (RES) became the major component of the head kidney. By 65 dph, the head kidney was histologically similar to mature fishes, formed as a lymphoid- adrenergic tissue. Cells producing IgM as lymphocytes were detected by immunohistochemistry (IHC)stain. A few PAS positive cells were observed by 7dph while several IgM positive cells were occasionally first detected at 17 dph. PAS positive cells and IgM positive cells were both increased with age and finally scattered all over the head kidney. In short, the head kidney in grass carp was almost mature histologically by 65 dph ; as a immune organ, the development of the head-kidney in juvenile grass carp can be divided into three stages characterized by the ⅰ) absence of cells involving in immunity, ⅱ) presence of cells only involved in nonspecific immunity, and ⅲ) emergence and proliferation of cells involving in both nonspecific and specific immunity.

    • Impact factors of sinking performance for tuna purse seine based on the generalized additive model

      2013, 37(6):944-950. DOI: 10.3724/SP.J.1231.2013.38336

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      Abstract:Tuna purse seining is the most efficient fishing method in the modern tuna fisheries, this present study analyzed the sinking performance in tuna purse seines and its relationships with impact factors, which are beneficial to improve efficient fishing in tuna purse seines. Based on the data collected from the tuna purse seiner “JINHUI 7” operating in the Western and Central Pacific Ocean (WCPO) during September to December 2011, the present study analyzed the relationship between sinking depth (H) and other variables, including shooting duration (T), shooting velocity (V0), length of purse line (L) , length of ran line (L1) and current speed (V10, V60 and V120) of 10m, 60m and 120m layers, the impact factors on sinking depth are also estimated using the generalized additive model (GAM). The results show that (1) the relationship between the sinking depth (H) and time (t) for the middle section of leadline can be described by the formula H = -0.0002 t2 0.4086t 1.8099 (R2 = 0.9993). (2) the sinking speed decrease with the increasing depth, the relationship between the sinking speed (V) at the middle part of leadline and time (t) can be described using the formula V = 2.5 × 10-7 t2 - 6 × 10-4t 0.4412 (R2 = 0.9852). (3) the analysis of stepwise GAM shows that four factors have a significant impact on the sinking depth (P < 0.05) and the significance can be ordered by V120, L ,T and V60; (4) the analysis of GAM shows that the sinking depth increases gradually with the increasing shooting duration, which concentrates on the period of 500-550s; current speed has a negative correlation to the sinking depth; the length of purse line is mainly concentrated in about 1800m.

    • Effects of salinity on Na /K -ATPase activity, the osmolality of pericardial cavity fluid and peritoneal fluid and ion content of Onchidium struma

      2013, 37(6):851-857. DOI: 10.3724/SP.J.1231.2013.38407

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      Abstract:To explore the effects of salinity on the Na /K -ATPase activity, the osmolality of pericardial cavity fluid and peritoneal fluid and ion content (Na , K and Cl-) in Onchidium struma, six hundred healthy specimens (wet weight 10.24 ? 2.16 g) were selected and had been raised for 30 days with simulated ecological environments that in different salinity conditions (5, 15, 25, 35 and 45). The results shows: 1) The salinity and osmolality of peritoneal fluid and pericardial cavity fluid of Onchidium struma are increased with increasing ambient salinity, and the increased amplitude of peritoneal fluid all greater than the pericardial cavity fluid. 2) The content of Na , Cl- and K of pericardial cavity fluid consistent with the changes of ambient salinity and these are all increased firstly then decreased. The concentrations of Na , Cl- and K reached the maximum at salinity 25 and salinity has a significant impact on Na and Cl- but with no significant effect on K . 3) There are significant differences on Na /K -ATPase activity of different parts in Onchidium struma. The Na /K -ATPase in cardia stomach, intestine, epidermis, muscle and pericardial cavity film of Onchidium struma have higher activity. In addition, the Na /K -ATPase activity of different parts activated by salinity with some tissue-specificity, there are higher activity of hepatopancreas, cardia stomach and epidermis in low salinity while the pyloric stomach, intestine, kidney and pericardial cavities film in high salinity. These results indicates that the salinity can significantly impact the osmolality and ion concentration of peritoneal fluid and pericardial cavity fluid as well as the Na /K -ATPase activity of Onchidium struma. The cardia stomach, intestine and muscle are main organs involved in its ion transport and osmoregulation with strong osmotic adjustment capability.

    • CPUE standardization of Illex argentinus for Chinese squid-jiggingfishery in Southwest Atlantic Ocean

      2013, 37(6):951-959. DOI: 10.3724/SP.J.1231.2013.37897

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      Abstract:Illex argentinus supports one of the most important Chinese mainland squid-jigging fisheries in the southwestern Atlantic Ocean. Assessment of this resource requires abundance index data such as catch per fishing effort (CPUE). However, fisheries CPUE data need to be standardized before they can be used in the stock assessment. Generalized linear models (GLM) and generalized additive models (GAM) were used to standardize CPUE of the Chinese mainland jigging fishery in the southwestern Atlantic Ocean during 2000~2010 using data collected by Chinese Squid-jigging Technology Working Group. Environmental variables collected include sea surface temperature (SST), sea surface height (SSH) and chlorophyll-a (Chl-a). The GLM analysis indicated that the significance of four variables ranked in decreasing importance: Year, Latitude, Year× Latitude and SST. However, the GAM showed that the model including Year, Month, Longitude, Latitude, SST, SSH, Year×Latitude and Year×Longitude was the optimal model based on AIC and could explain 49.20% of the variance in the nominal CPUE. The GAM analysis indicated that high CPUEs were found in the area between 46.5?-48.5?S with SST ranging from 28 to 31?C in summer., SSH raging form -20 to 20cm. The GAM tended to be more suitable than GLM in the CPUE standardization in this study.

    • Effects of high temperature on the immuno-enzymetic activity in coelomic fluid of Mizuhopecten yessoensis

      2013, 37(6):858-863. DOI: 10.3724/SP.J.1231.2013.38305

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      Abstract:In this study, we tested the high temperature mutation tolerance,survival and immune enzyme activity under different high temperature level of Mizuhopecten yessoensis. There are two stages in our laboratory experiments, firstly, we transferred scallops from the rearing temperature (15℃,control temperature) to 20、22、24and 26℃, and then we tested the survival and related immune indicators of M.yessoensis. The survival of M.yessoensis was not affected by temperature from 15℃ to 22℃ with survival rate exceeding 85.21%, and there is no significant difference in different group (P>0.05), Scallops exposed to 26℃ were significantly affected by temperature, with a survival of 26.33%. With the temperature rising, the T-AOC and MDA content In the body cavity fluid of M.yessoensis significantly changed (P<0.05). The CAT vitality would rise after the first drop with the rise of temperature. There were no significant differences among different groups SOD vitality (P>0.05). Secondly, we abruptly transferred scallops from the rearing temperature (15℃,control temperature) to 20、22、24 and 26℃ level, and examined related immune index in the presence of 1h, 2h, 4h, 8h, 12h, 24h, 48h and 96 h. The results showed that, The survival of M.yessoensis was not affected by temperature from 15℃ to 24℃ during the 96-h exposure periods with survival rate exceeding 82.29%. Scallops exposed to 26℃ were significantly affected by temperature, with a survival of 0% after 12h. The 8-, 12-, 24-, 48- and 96h lethal temperature for 50% (LT50) were 27.52, 24.41, 24.37, 24.24 and 23.81℃ respectively.

    • A fluorescent staining method for marking the cuttlefish, Sepiella Maindroni De Rochebrune

      2013, 37(6):864-870. DOI: 10.3724/SP.J.1231.2013.38443

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      Abstract:It is necessary to establish a highly efficient method of marking, which providing technical guarantee for a more accurate assessment of stock-enhancement effect of the cuttlefish (Sepiella japonica). The cuttlefish were chosen as the experimental material in this study. The larval cuttlefish were immersed in alizarin complexone (ALC) to dye the cuttlebone. The experiment was divided into 5 groups with concentration gradient and 2 time periods, and doral mantle length, body weight and survival rate of cuttlefish were measured and observed. The trial group and control group (50 ind/group) were reared in 2.5 m diameter circular concrete ponds, respectively. The cuttlefish were sampled randomly in order to examine the dye-retention of the tagged cuttlebone after being tagged 5, 12, 19, 26 d. Moreover, the tagged cuttlefish were examined at high temperature treatment for 5 min. The results showed that the optimised dye concentration and immerged time were 90 mg/L and 24 h, respectively. The doral mantle length of cuttlefish had a significant positive correlation with body weight (P<0.01), and there was no significant difference in growth between trial group and control group (P>0.05). The tagged oval pink ring was still clear in the cuttlebone even after being tagged 26 d. The range and color of tagging parts were not changed before and after high temperature treatment. Additionally, the proposed method has effect on both internal signs and external signs, and the survival rate and dye-retention rate of the tagged cuttlefish are 100%. It is concluded that this method can be successfully applied for marking cuttlefish, and offer a number of benefits, including simple, efficient, high sample throughput, and a wide range of application prospect.

    • Observation on tetrad development and formation of sex phenotype of Pyropia haitanensis blades in natural conditions

      2013, 37(6):871-883. DOI: 10.3724/SP.J.1231.2013.38670

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      Abstract:The cross between a red-mutant (R, ♀) and a wild type (W, ♂) of Pyropia haitanensis in laboratory demonstrated that its gametophytic blades were mainly monoecious. However, sexual observations showed a contrary result in the wild populations of this species. In order to clarify the real sex of the wild blades, some of the key issues related to this discrepancy were studied in this paper. Sequencing analysis of 5.8S rDNA region demonstrated that the monoecious and dioecious blades in wild populations of P. haitanensis were the same species. In nature, the heterozygous conchocelis produced in the cross between a red mutant and the wild type was cultivated, and the conchospores released from mature conchocelis were cultivated into F1 blades. Microscopic observation showed that two parental color sectors (W sector and R sector) and two recombinant color sectors (R′ sector and W′ sector) appeared in F1 blades, and 95.6% of the young blades (about 5 mm in length) were linearly sectored with 2-4 color-sectors. Besides, when those young blades grow up, each mature color-sector in the sectored blade was unisexual (either male or female). Therefore, the color-sectored blades were also the sex-sectored blades. Those findings tallylied with those obtained in laboratory, indicating that neither the position of meiosis nor segregation mode of the parental sex was change in natural conditions. However, during subsequent development of the young blades, one or two basal color-sector(s) was arrested severely. As a result, they formed very small areas on the blade which were hardly discerned by naked eyes. The area composed the rhizoid or basal part of the adult blade which could hardly maturate. Nearly entire blade was derived from one or two top color-sector(s), therefore color-sectored blades dropped to 42.1%. However, the uppermost sector took very large area of the blade and its maturity was much earlier than the middle and basal part. As a result, in the beginning and middle stages of the maturity, almost all the mature parts of the blades were in the upmost sector, and their phenotype showed unisexual even though they were monoecious actually. At the end of maturity of the blades, the middle sectors started to maturate, so the percentage of monoecious blades increased significantly. The results above showed that the wild blades of P. haitanensis in nature were also mainly monoecious. However, the probability for observation of its real sex was greatly reduced because of the uneven development of the tetrad and the asynchronous maturity of the top, middle and base of the blades. Due to these factors, one-time sampled by naked eyes often revealed that the wild blades were dioecious phenotype, with a few exceptions of monoecious phenotype.

    • Spatial distribution mechanism of Sargassum horneri around Gouqi Island, Shengsi,China*.

      2013, 37(6):884-893. DOI: 10.3724/SP.J.1231.2013.38429

      Abstract (2744) HTML (0) PDF 1.41 M (2057) Comment (0) Favorites

      Abstract:This research surveys distribution and growing states of S.horneri under different habitat by using underwater quadrat sampling method, and also studies the relationship, in both large and small scales (among sites and inside site), between the spatial distribution of S.horneri and influenced factors, thus provides references to protect and recover seaweed field. It has been found that in among sites , much of S.horneri grows in sheltered bay, where plant distribution density and plant length are obviously higher than those in stations of wave exposure (P<0.05), while water motion and turbidity in sites of wave exposure are inversely more remarkable than those in sheltered sites (P<0.05), which suggests that water motion become a limiting factor on the horizontal distribution and growing of S.horneri. Within site, the vertical distribution of S.horneri has distinctive characteristics. Distribution density and plant length of S.horneri at the bottom of intertidal zone are obviously higher than those in subtidal zone (P<0.05).Study result also shows that, in small scale, the distribution density and plant length of S.horneri have some degree of correlation with the roughness, slope gradient and slope aspect of attachment substances. However, correlation analysis manifests that water depth has the highest correlation with the distribution density and plant length of S.horneri (r=-0.337,p=0.001), and roughness has a second highest correlation (r=0.175,p=0.092), while slope gradient and slope aspect merely have small correlation.So,it indicates that light condition maybe become the other limiting factor on the vertical distribution and grow of S.horneri.Study finally finds that physical characters of attachment substances are not the vital factors in affecting the distribution of S.horneri. We can infer that sediment is the key factor in affecting spatial distribution pattern of S.horneri,as a result of water motion arise resuspention of sediment to influence the light condition which S.horneri need.

    • Community structure of zooplankton and its relation to environment factors in silver carp and bighead carp dominated Qian dao lake

      2013, 37(6):894-903. DOI: 10.3724/SP.J.1231.2013.37834

      Abstract (2631) HTML (0) PDF 1.74 M (2738) Comment (0) Favorites

      Abstract:From 2007 to 2008, a monthly investigation was conducted to study the zooplankton community structure and water environmental factors in Qiandao Lake. A total of 115 species of zooplankton were identified including 4 groups i.e. Protozoa (16 species), Rotifer (51 species), Cladocera (23 species) and Copepoda (25 species). Horizontal and temporal distributing characters of zooplankton communities were analyzed. Density of zooplankton presented a pattern of single peak in spring in two years ,peaked at 840.9 ind./L in May 2007, 850.5 ind./L in june 2008 separately; Biomass of zooplankton presented two-peak in spring and autumn , peaked at 1.89 mg/L in May 2007, 0.837 mg/L in August 2007, 1.63 mg/L in May 2008年、0.802 mg/L in August 2008. Densiey and biomass of zooplankton decreased sequentially as the following order:river region > transition zone > lake region . According to the variety in vertical distribution,density of zooplankton were distributed throughout every layer of water body, reaching the biomass maximum at the depth of 4 meter in river region(sampling 1 ) and transition zone (sampling 4) , and reaching the biomass maximum at the depth of 8 meter in lake region (sampling 9) .The significant factors affecting zooplankton distribution were DO, CODMn, water temperature, TN, NO2-N, TP, NO3-N. Biomass of Protozoa and Copepod were positively correlated with DO, the biomass of Rotifer and Cladocera were positively correlated with TN, NO3 and the biomass of phytoplankton.Canonical correspondence analysis ( CCA) was applied to explore the relationship between variation of dominant species of zooplankton and environmental factors. The results showed that certain species, such as Tintinnidium entzii,T.fluviatile,Daphnia hyalina were positively associated with DO as well as negatively associated with water temperature. Among other species, Keratella.tcinensis,Bosmina coregoni,B.longirostris were correlated positively with TP,TN,NH3-N ,NO3- while Hexarthra.mira, Mesocyclops leuckarti were showed positive correlation with Chla. Most Copepoda such as Mesocyclops leuckarti, Neutrodiaptomus incongruens were positively associated with water temperature. Meanwhile, the biomass of Daphnia was positively correlated with biomass of phytoplankton from February to june, negatively correlated with water temperature in other month.

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