The complete diallel cross design was employed to estimate the genetic parameters of the growth of Japanese flounder （Paralichthys olivaceus）. A total of 60 full-sib families were cultivated and two growth-related t...The complete diallel cross design was employed to estimate the genetic parameters of the growth of Japanese flounder （Paralichthys olivaceus）. A total of 60 full-sib families were cultivated and two growth-related traits, body weight （BW） and body length （BL）, were examined at average 2, 3 and 8 months of age respectively, with 1 800 individuals measured in each age group （30 per family）. Based on the additive-dominance-maternal-effect genetic analysis model, the restricted maximum likelihood approach was used to estimate various （co）variance components. The results showed that narrow-sense heritability estimates of BW and BL were respectively： 0.29 ± 0.01 and 0.22 ± 0.02 at 2 months of age, 0.32 ± 0.02 and 0.30 ± 0.04 at 3 months of age, 0.48 ± 0.04 and 0.40 ± 0.05 at 8 months of age; broad-sense heritability estimates were respectively： 0.44 ± 0.02 and 0.54 ± 0.04 at 2 months of age, 0.35 ± 0.01 and 0.36 ± 0.03 at 3 months of age, 0.49 ± 0.03 and 0.45 ± 0.04. All heritabilities were statistically significant （P 0.05）. Additive genetic correlations between BW and BL at 2, 3 and 8 months of age were consistently positive and highly significant （P 0.01）： 0.93 ± 0.02, 0.95 ± 0.03 and 0.92 ± 0.03 respectively. Maternal effect was significant （P 0.05） only at 2 months of age, and was not detected at 3 and 8 months of age. According to the heritability estimates, the mass selection strategy should be efficient for the breeding of Japanese flounder.展开更多
The inability of Fenneropenaeus chinensis to tolerate low temperatures is of major economic concern in temperate climates,as it reduces their growing season and leads to over-winter mortality.In this study,the heritab...The inability of Fenneropenaeus chinensis to tolerate low temperatures is of major economic concern in temperate climates,as it reduces their growing season and leads to over-winter mortality.In this study,the heritability of body weight under low grow-out temperature and cold tolerance in F.chinensis were first investigated and estimated using 88 ful-sib families,which might provide crucial information in Chinese fleshy prawn breeding programs.The heritability for body weight under suitable and low temperature of F.chinensis were both moderate（0.158 0±0.307 5 and 0.132 0±0.026 9 respectively）;the large coefficient of variation（approximately 21%） and moderate estimate of heritability for body weight indicated substantial potential for selective breeding.The heritability estimate for cold tolerance was low（0.019 2±0.023 5）,and showed no significant differences from zero（P〉0.05）.A weak genetic correlation between cold tolerance and body weight was also estimated in the present study,also showing no significant differences from zero（P〉0.05）.Thus,more research needs to be conducted on the more accurate heritability estimate of cold tolerance and genetic correlations between traits in F.chinensis to further improve the achievement of breeding goals.展开更多
Through exploring the microsatellite primers from the random genome sequences of Chinese shrimp （Fenneropenaeus chinensis）, some microsatellite primers were obtained with rich polymorphic genetic information, and a ...Through exploring the microsatellite primers from the random genome sequences of Chinese shrimp （Fenneropenaeus chinensis）, some microsatellite primers were obtained with rich polymorphic genetic information, and a triplex PCR was established using three primers （RS1101, RS0683 and H081 primers）. By adjusting the final concentration of Mg^2＋, dNTP and primers, and using a touch-town PCR program, the optimum amplification parameters of PCR system were obtained, which could successfully amplify the three primers in a PCR reaction. In the denatured PAGE gel, the amplified DNA fragments of three primers RS1 101,RS0683 and H081 could be easily identified each other. For the triplex PCR system, the PPE （probabilities of paternity exclusion） is 0.967 9,and the DP （discrimination power） is 0.999 327.Using the triplex PCR to test ten individuals of a parentage and their parents, an individual was excluded from the parentage in all of the three microsatellite loci, which might be mixed into the parentage for some unknown reason such as factitious misplay. The triplex PCR will be of great practical value in identifying the parentages of F. chinensis.展开更多
Anchovy is a key species in the Yellow Sea ecosystem. An accurate estimate of anchovy abundance is vital for the management of the anchovy stock and measurement of the ecosystem response to changes in anchovy abundanc...Anchovy is a key species in the Yellow Sea ecosystem. An accurate estimate of anchovy abundance is vital for the management of the anchovy stock and measurement of the ecosystem response to changes in anchovy abundance. However, the acoustic fish abundance estimate may be biased by 30%-40% if the fat-content induced target strength variation is not taken into account. We measured the monthly variation in the fat content of anchovy (Engraulis japonicus) in the Yellow Sea, and evaluated the potential effect of variation in fat content on the acoustic assessment of anchovy abundance. The fat content of anchovy varied seasonally, with two maxima and two minima in a year. The highest fat content (14.75%) was measured in the pre-spawning period in May, and the lowest fat content (2.48%) was measured during the post-spawning period in October. Fat content appeared to correlate with water content, but not body size. Assuming that the target strength is decreased by 0.2dB for every 1% increase in fat content, the seasonal difference in the target strength of anchovy may be as high as 2.45 dB. Given this, the acoustic abundance estimate may be biased by between 43% and 76%. Our results highlight the need for more information on the changes in fat content of fishes whose abundance is estimated by acoustic surveys.展开更多
The present study investigated the applicability of integrated polychaete-fish culture for fish waste removal to offset negative impact induced by organic benthic enrichment.A field study demonstrated that deposition ...The present study investigated the applicability of integrated polychaete-fish culture for fish waste removal to offset negative impact induced by organic benthic enrichment.A field study demonstrated that deposition rate was significantly higher underneath the fish farm than that in control area.The material settling under the farm was characterized by a high amount of fish feces(45%) and uneaten feed(27%).Both feeding rate(FR) and apparent digestibility rate(ADR) increased with decreasing body weight,as was indicated by significantly a higher rate observed for the groups containing smaller individuals in a lab study.The nutrient in fresh deposited material(De) was higher than that in sediments collected under the farm(Se),resulting in lower feces production but higher apparent digestibility rate for the De group as feeding rate was similar.Consequently,higher nutrient removal efficiency was observed in the De group.A mass balance approach indicated that approximately 400–500 individuals m^(-2) is required for removing all waste materials deposited underneath the fish farm,whereas abundance can be lower(about 300–350 individuals m^(-2)) when only the fish waste needs to be removed.The results showed that a significant amount of waste had been accumulated in the fish cages in Sanggou Bay.The integration of fish with P.aibuhitensis seems promising for preventing organic pollution in the sediment and therefore is an effective strategy for mitigating negative effect of fish farms.Thus such integration can become a new IMTA(integrated multi-trophic aquaculture) model in Sanggou Bay.展开更多
In this study,families of selected population for growth(SP_BWT),selected population for white spot syndrome virus(WSSV)resistance(SP_RW),Bohai wild population(WP_BH)and Huanghai wild population(WP_HH)of F.chinensis w...In this study,families of selected population for growth(SP_BWT),selected population for white spot syndrome virus(WSSV)resistance(SP_RW),Bohai wild population(WP_BH)and Huanghai wild population(WP_HH)of F.chinensis were constructed through artificial insemination and with the standardized procedure of larvae rearing.Growth and survival performance were studied among four populations after a 70 days common test.The results showed that the maximum least square mean of body weight was 17.50 g in SP_BWT while the minimum was 13.03 g in WP_HH.Compared with WP_BH,body weight of SP_BWT increased by 23.41%(P<0.01)and that of SP_RW by 12.20%(P>0.05).Body weights of SP_BWT and SP_RW were significantly higher than that of WP_HH,which increased by 34.31%(P<0.01)and 22.10%(P<0.05),respectively.The mean AGR of four populations was 0.19,0.18,0.17 and 0.16 g d^(-1),respectively.Coefficient of variation of body weight among four populations was high,which ranged from 32.67% to 35.25%.Such a range showed that there was the potentiality for further improvement in selected populations.Coefficient of variation of survival rate among four populations was low,varying between 3.20% and 5.90%.The difference of survival was highly significant(P<0.01)between SP_BWT and WP_BH,and significant(P<0.05)between SP_RW and WP_BH.However,no significant difference among other populations(P>0.05)was observed.Different growth performances were also observed among different families in each population.The body weight of 798F family was the highest.The absolute growth rate(AGR)was 0.25 g d^(-1),150%higher than that of the lowest one,0.1 g d^(-1) in 807F family.Survival rate of families among four populations was different.The highest was 94.74%,and the lowest was 71.88%.展开更多
To investigate the genetic components of growth in the brine shrimp Artemia sinica, we estimated the genetic parameters of body length and the response to selection using a fully pedigreed population of A. sinica. The...To investigate the genetic components of growth in the brine shrimp Artemia sinica, we estimated the genetic parameters of body length and the response to selection using a fully pedigreed population of A. sinica. The base population was generated from four wild founder populations. We tested 4160 offspring in 360 families over four generations for growth and survival performance. Across four generations, we produced full-and half-sib families with nested mating, where two dams were mated to the same sire. Individual body length was measured for each nauplius at day 20 post-hatching. Heritability of body length was estimated across four generations with the restricted maximum likelihood method. The heritability of body length in A. sinica was low(0.14 ± 0.05), and the common environmental effect was 0.14 ± 0.02. We estimated the response to selection for body length by calculating the difference in the mean breeding values between different generations. The accumulated genetic gain in body length was 278.94 μm after three generations of selection. This low response to selection was probably caused by the low heritability of body length, small sample size, and the low selection intensity(50%). The results suggest that A. sinica selective breeding programs must be changed to generate any substantial, sustainable genetic increases in body length. We suggest that optimal genetic gains could be achieved by introducing wild strains into the nuclear breeding population to increase genetic variation, and by increasing the size of the breeding population to allow for increased selection intensity.展开更多
Two transcription factors, Sox9a and Foxl2 were cloned from half-smooth tongue sole （Cynoglossus semilaevis）. Sox9a is a new duplication of C.semilaevis Sox9 gene. The complete cDNA of Sox9a gene was 1 842 bp long c...Two transcription factors, Sox9a and Foxl2 were cloned from half-smooth tongue sole （Cynoglossus semilaevis）. Sox9a is a new duplication of C.semilaevis Sox9 gene. The complete cDNA of Sox9a gene was 1 842 bp long coding for 487 amino acids and Foxl2 gene was 1 817 bp coding for 308 amino acids. Sox9a was expressed higher in male brain, pituitary and gonad and Foxl2 were higher in female brain, pituitary and gonad. The expression of Sox9a gene in gonads of neo-males was higher than that of normal females. Sox9a and Foxl2 were expressed higher in gastrula stage than in other stages. In the period of sex differentiation, the expression of Sox9a was first going up and then going down and Foxl2 was higher expressed at 37 dph. The highest expressions of Sox9a and Foxl2 genes occurred in nine-month and 12-month old gonad tissues, respectively. Sox9a gene was considered to have inevitable links with sex reversal, sex differentiation and cell differentiation of embryos and formation of spermatogenic ceils. Foxl2 was considered to play a role in sex differentiation, cell differentiation of embryos but not to be necessary for sex determination and sex reversal.展开更多
An analysis of a selection experiment was used to assess the impact of various animal model struc- tures on REML estimates of variance components. The analyses were carried out based on 162 d body mass （BM） of 1 287...An analysis of a selection experiment was used to assess the impact of various animal model struc- tures on REML estimates of variance components. The analyses were carried out based on 162 d body mass （BM） of 1 287 animals from 21 paternal half-sib groups of Fenneropenaeus chinensis. Estimated breeding values （EBV） of BM of all individuals were estimated using eight statistical models （A, AB, ABC, ABDC, ABMFC, ABMDC, ABFDC and ABMFDC） and BLUP （best linear unbiased prediction）. These models were designed involving factors such as sex, spawn date as fixed effects, maternal genetic effects, full-sib family effects as random effects, mean BM of families at tagging and age at recording （covariate）. The results demonstrate the importance of correct interpretation of effects in the data set, particularly those that can influence resemblance between relatives. The data structure and the particular model that was applied markedly influenced the magnitude of variance component estimates. Models based on few effects obtained upward biased estimates of additive genetic variance. The accuracy of genetic parameters and breeding value es- timated by ABFDC model was higher than other models. The results imply that additive genetic direct value, full-sib family effects, and covariance effects besides sex and spawn date as fixed effects were very important for estimating genetic parameters and breeding value of body mass. This model had a heritability estimate of 162 d BM of 0.44. The comparison of the efficiency of selection based on breeding values or phenotypic value revealed great difference： average breeding value of the best 24 families selected by the 162 d BM breeding value and phenotype were 0.577 g and 0.366 g, respectively, representing a 36.57% higher efficiency in the former. In conclusion, selection based on breeding value was more effective than selection based on phenotypic value. Our results indicate that effects influencing the magnitude of estimates should be taken into account when estimating heritability and breeding values for BM.展开更多
A muhispecies model for shellfish polycuhure in the Sanggou Bay in China used for large-scale long-line cultivation of the Chinese scallop Chlamysfarreri, the Pacific oyster Crassostrea gigas and the kelp Laminaria ja...A muhispecies model for shellfish polycuhure in the Sanggou Bay in China used for large-scale long-line cultivation of the Chinese scallop Chlamysfarreri, the Pacific oyster Crassostrea gigas and the kelp Laminaria japonica is presented. The model includes key physical processes which are the transports of matter at the system boundary, and the main biological process that is the primary production and nutrients release from the bottom. By the model, the seasonal fluctuations of phytoplankton biomass and dissolved inorganic nitrogen（DIN） in 1994 are simulated. Furthermore, if the kelp culture scale is kept constant and the Chinese scallop and the Pacific oyster culture scales are adjusted, virtual shellfish farms are funded and responses of phytoplankton to the largescale shellfish culture are simulated. According to these simulated results, the room limitation, and the hypothesis that shellfish will not grow well if the phytoplankton biomass is less than 8.2 mg/m^3 , the expandable multiple of scallop culture k and that of oyster culture y are determined as k = -0.276 5y ＋4.690 5 and 0.133 3k ＋0.006 6y≤0.667 5, where, k （ or y） is equal to 1, the culture scale of scallop （ or oyster） is 8.8 x 109 individuals （or 66 ha, with a density of 59 ind./m^2 ）, and the kelp culture scale is 3 300 ha with a density of 12 ind./m^2.展开更多
Twenty-six half-sib groups （53 full-sib families） of turbot,Scophthalmus maximus Linnaeus, were obtained by artificial insemination. We measured growth in the offspring （40-50 individuals/family） and subjected the...Twenty-six half-sib groups （53 full-sib families） of turbot,Scophthalmus maximus Linnaeus, were obtained by artificial insemination. We measured growth in the offspring （40-50 individuals/family） and subjected them to a thermal tolerance challenge over a period of 34 d. There was no significant difference in daily mor-tality （range： 0.580%-1.391%） between Days 1-13 during the thermal tolerance challenge. However, daily cumulative mortality increased rapidly between Days 14 and 29, especially on Days 15 and 16 （20.232% and 34.377%, respectively）. Mortality was highest on Day 16 （14.145%）. We estimated the genetic parameters using the average information restricted maximum likelihood method. We used a likelihood ratio test to evaluate the significance of effects in models with and without identity as an effect, and compared the final log-likelihoods （maximum log L）. Lastly, we estimated phenotypic and genetic correlation between the up-per thermal tolerance limit （UTT） and body weight （BW）. In this study, the positive phenotypic correlation was low between UTT and BW （0.093±0.029）. The genetic correlation between UTT and BW was negative （-0.044±0.239）. The heritability for upper thermal tolerance was low （0.087±0.032）, which is of approximate-ly moderate heritability. The heritability for body weight was high （0.303±0.074）. Our results suggest there is significant potential for improvement in the culture of turbot by selective breeding.展开更多
Seven microsatellite markers were used to evaluate the genetic diversity and differentiation of seven stocks of Litopenaeus vannamei, which were introduced from Central and South America to China. All seven microsatel...Seven microsatellite markers were used to evaluate the genetic diversity and differentiation of seven stocks of Litopenaeus vannamei, which were introduced from Central and South America to China. All seven microsatellite loci were polymorphic, with polymorphism information content(PIC) values ranging from 0.593 to 0.952. Totally 92 alleles were identified, and the number of alleles(Na) and effective alleles(Ne) varied between 4 and 21 and 2.7 and 14.6, respectively. Observed heterozygosity(Ho) values were lower than the expected heterozygosity(He) values(0.526–0.754), which indicated that the seven stocks possessed a rich genetic diversity. Thirty-seven tests were detected for reasonable significant deviation from Hardy-Weinberg equilibrium. Fis values were positive at five loci, suggesting that there was a relatively high degree of inbreeding within stocks. Pairwise Fst values ranged from 0.0225 to 0.151, and most of the stock pairs were moderately differentiated. Genetic distance and cluster analysis using UPGMA revealed a close genetic relationship of L. vannamei between Pop2 and Pop3. AMOVA indicated that the genetic variation among stocks(11.3%) was much lower than that within stocks(88.7%). Although the seven stocks had a certain degree of genetic differentiation and a rich genetic diversity, there is an increasing risk of decreased performance due to inbreeding in subsequent generations.展开更多
We analyzed the survival data of the offspring from 21 sires and 42 dams of turbot. The results show that the cumulative survival rates for turbot from 2 to 18 months range from 17.5% to 28.5% main mortality occurred ...We analyzed the survival data of the offspring from 21 sires and 42 dams of turbot. The results show that the cumulative survival rates for turbot from 2 to 18 months range from 17.5% to 28.5% main mortality occurred during months 2-5; and the highest survival rates of families were 97.9%, 98.8%, 99.4%, 99.7% during months 2-5, 5-6, 6-8, 8-11, and ll-18, respectively, and 99.5%, being 53.5%, 23.8%, 19.5%, 14.9%, and 13.2% higher, respectively, than the mean values in each period. In all periods, the estimated heritabilities for survival were very low without significant difference from zero （P〉0.05） （values ranged from 0.06 to 0.12）, indicating low additive genetic effects. The genetic correlations of survival among families in different periods were all positive, but low in magnitude （values range from 0.03 to 0.31）. Genetic correlations between long-term survival and other periods＇ survival had negative values （-0.06 and -0.15） and three positive values （0.16, 0.12 and 0.14）. Genetic correlations between survival and weight were all positive, except for survival at months 2-5 and weight at 18 months, which was not significantly negative （-0.18）.展开更多
Taxonomic diversity of fish assemblages in the Changjiang Estuary （Yangtze River Estuary） and its adjacent waters was analyzed based on bottom trawl surveys carried out by R/V Beidou in June, August and October 2006...Taxonomic diversity of fish assemblages in the Changjiang Estuary （Yangtze River Estuary） and its adjacent waters was analyzed based on bottom trawl surveys carried out by R/V Beidou in June, August and October 2006. Four groups of fishes were identified for each survey by the twoway indicator species analysis （TWIA）. Taxonomic distinctness, species richness and phylogenetic diversity were used to detect changes in taxonomic structure of fish assemblages. Most dominant fish species mainly belonged to Perciformes, Pleuronectiformes, Clupeiformes, Scorpaeniformes and Tetraodontiformes. Species richness in offshore waters of the survey area was higher than that in the other area. The average taxonomic distinctness value （AvTD,△^＋） of each fish assemblage was close to the average taxonomic distinctness of master list in the Changjiang Estuary （79.9）, and had a positive correlation with species richness and Shannon diversity index （H′）. A negative correlation was found between variations in taxonomic distinctness （VarTD, A^＋） and traditional diversity indices, which were caused by fish species component that led to longer average path lengths among species. Taxonomic diversity index （△） had the similar results with species richness, Ht, Simpson diversity index （D） and Pielou＇s evenness index （J′）. VarTD also kept stable, which further certificated that fish assemblages and ecological environment were in equilibrium. Taxonomic distinctness index （△^＋） was relatively stable in most of fish assemblages, and had higher values in some fish assemblages for a few absolutely dominant species. The present study showed that fish community formed new equilibrium stability in 2006 in the Changjiang Estuary when compared with those in the corresponding months of annual survey from 1985 to 1986. And AvTD in each sampling station was lower than AvTD of master list in the Changjiang Estuary, so some ecological niches were absent in each sampling stations from taxonomic or phylogenetic relationships, these would be helpful to stock natural resource and maintain ecological equilibruim of fish assemblages.展开更多
A mass-balanced model was constructed to determine the flow-energy in a community of fishes and invertebrates in the Beibu Gulf, northern South China Sea using Ecopath and Ecosim software. Input parameters were taken ...A mass-balanced model was constructed to determine the flow-energy in a community of fishes and invertebrates in the Beibu Gulf, northern South China Sea using Ecopath and Ecosim software. Input parameters were taken from the literature, except for the biomass of fish groups which was obtained from trawl surveys during October 1997 to May 1999 in the study area. The model consisted of 16 functional groups （boxes）, including one marine mammal and seabirds, each representing organisms with a similar role in the food web, and only covered the main trophic flow in the Beibu Gulf ecosystem. The results showed that the food web of Beibu Gulf was dominated by the detrital path and benthic invertebrates played a significant role in transferring energy from the detritus to higher trophic levels; phytoplankton was a primary producer and most utilized as a food source. Fractional trophic levels ranged from 1.0 to 4.08 with marine mammals occupying the highest trophic level. Using network analysis, the system network was mapped into a linear food chain and six discrete trophic levels were found with a mean transfer efficiency of 16.7% from the detritus, 16.2% from the primary producer within the ecosystem. The biomass density of the commercially utilized species estimated by the model is 8.46 t/km^2, only O. 48% of the net primary production.展开更多
A simulation method based on the lumped mass model is proposed for determining the dynamic behavior of nets exposed to a uniform current. Every mesh bar is modeled by a linear bar clement. The lumped mass point is set...A simulation method based on the lumped mass model is proposed for determining the dynamic behavior of nets exposed to a uniform current. Every mesh bar is modeled by a linear bar clement. The lumped mass point is set at the ends of each element. The net can be simulated by a discretized model consisting of many point masses and elements without mass. 3D shapes and the distribution of tensions of the net at different moments can be found from time integration of a set of motion equations with a computer program. Two nets are simulated according to reference experiments. Calculated results are in accordance with experimental results. The method is applicable and can be applied to improving design of, and research into other flexible structures, such as net cages.展开更多
The status of fishery stocks in the coastal waters of China is far from ideal, mainly due to climate change and the impacts of human activities （e.g., pollution and overfishing）. Thus, the restoration and protection...The status of fishery stocks in the coastal waters of China is far from ideal, mainly due to climate change and the impacts of human activities （e.g., pollution and overfishing）. Thus, the restoration and protection of fishery resources have become critical and complex. The stability and balanced structure of the fish community is a basic foundation for the protection of fishery resources. Based on data collected from bottom trawls by the R/V Beidou in continental shelf of the East China Sea in November 2006 and February 2007, changes in the composition and diversity of fish species and functional groups were analyzed. The research area was divided into offshore waters and inshore waters by the two-way indicator species analysis （TWIA）. The results showed that the dominant species were different between offshore waters and inshore waters and also varied with the survey time. The most abundant family was Sciaenidae and Teraponidae in November 2006, Sciaenidae, Engraulidae and Triglidae were most abundant in February 2007. The species belonged mainly to mobile piscivores （G6）, benthivores/piscivores （G4）, benthivores （G3） and planktivores （G1）, and the dominant species in November 2006 were commercial species （e.g. Larimichthys polyactis and Trichiurusjaponicus）, but small-sized species were dominant in February 2007 （e.g., Harpadon nehereus, Benthosema pterotum, Champsodon capensis, and Acropoma japonieum）. The species diversity showed a similar trend as the functional group diversity. Stations with higher diversity were mainly distributed in inshore waters in February 2007, whereas higher diversity was found in offshore waters in November 2006. The highest biomass and species number were found in G6 group, followed by the G4, G5 and GI groups. The distribution of the number of individuals of each functional group showed the opposite trend as that of the biomass distribution. In addition, the size spectra were mainly concentrated around 3-29 cm, and the individual number of fish species gradually decreased with the increase in body size, but the relative biomass showed a moderate fluctuation in each size class. These changes showed that species with faster growth rate and earlier maturity age became dominant in continental shelf of the East China Sea. So the variations in biological characteristics of fish should be fully considered in maintaining sustainable utilization of fishery resource.展开更多
Noroviruses (NoVs) are widespread causes of nonbacterial gastroenteritis. Outbreaks of NoVs caused diseases are commonly ascribed to the consumption of contaminated shellfish. The concentration and RNA extraction of N...Noroviruses (NoVs) are widespread causes of nonbacterial gastroenteritis. Outbreaks of NoVs caused diseases are commonly ascribed to the consumption of contaminated shellfish. The concentration and RNA extraction of NoVs are crucial steps of detecting NoVs in shellfish. This study aimed to select a simple, rapid and highly efficient recovery method of NoVs detection with real-time RT-PCR. Four methods of recovering GI.3 and GII.4 NoVs from spiked digestive tissues of oysters and clams, respectively, were compared, of them, the method involving proteinase K and PEG 8000 was found the most efficient. With this method, 9.3% and 13.1% of GI.3 and GII.4 NoVs were recovered from oysters and 9.6% and 12.3% of GI.3 and GII.4 NoVs were recovered from clams, respectively. This method was further used to detect NoVs in 84 oysters (Crassostrea gigas) and 86 clams (Ruditapes philippinarum) collected from 10 coastal cities in China from Jan. 2011 to Feb. 2012. The NoVs isolation rates were 10.47% of clams (9/86) and 7.14% of oysters (6/84). All the detected NoVs belonged to genotype GII. The NoVs recovery method selected is efficient for NoVs detection in oysters and clams.展开更多
The dinoflagellate Prorocentrum minimum,one of the most widespread red tide causing species,affects marine aquaculture and ecosystems worldwide.In this study,ridgetail white prawn Exopalaemon carinicauda were exposed ...The dinoflagellate Prorocentrum minimum,one of the most widespread red tide causing species,affects marine aquaculture and ecosystems worldwide.In this study,ridgetail white prawn Exopalaemon carinicauda were exposed to P.minimum cells(5 × 104 cells mL-1) to investigate its harmful effects on the shrimp.Antioxidant activities and histological changes were used as indicators of health status of the shrimp.In 72 hours,the mortality of E.carinicauda was not affected,but its antioxidant response and histology were statistically different from those of control.Elevated superoxide dismutase(SOD) and glutathione peroxidase(GPX) activities and depressed catalase(CAT) activity were observed in gill;while increased SOD,glutathione S-transferase(GST),CAT activities and modulated GPX activity were observed in hepatopancreas.Thus,antioxidant activities in gill and hepatopancreas seem to respond differentially to harmful alga exposure.Increased malondialdehyde(MDA) content in early a few hours indicates the damage of the antioxidant defense system.Although MDA content recovered to a low level thereafter,a series of histological abnormalities including accumulation or infiltration of hemocytes,tissue lesions and necrosis were discovered in gill and hepatopancreas.Exposure to P.minimum induced sublethal effects on E.carinicauda,including temporary oxidative damage and histological injury.展开更多
Ammonia,toxic to aquaculture organisms,represents a potential problem in aquaculture systems,and the situation is exacerbated in closed and intensive shrimp farming operations,expecially for Litopenaeus vannamei.Asses...Ammonia,toxic to aquaculture organisms,represents a potential problem in aquaculture systems,and the situation is exacerbated in closed and intensive shrimp farming operations,expecially for Litopenaeus vannamei.Assessing the potential for the genetic improvement of resistance to ammonia in L.vannamei requires knowledge of the genetic parameters of this trait.The heritability of resistance to ammonia was estimated using two descriptors in the present study:the survival time(ST) and the survival status at half lethal time(SS_(50)) for each individual under high ammonia challenge.The heritability of ST and SS_(50) were low(0.154 4±0.044 6 and 0.147 5±0.040 0,respectively),but they were both significantly different from zero(P<0.01).Moreover,these two estimates were basically the same and showed no significant differences from each other(P>0.05),suggesting that ST and SS_(50) could be used as suitable indicators for resistance to ammonia.There were also positive phenotypic and genetic correlation between resistance to ammonia and body weight,which means that resistance to ammonia can be enhanced by the improvement of husbandry practices that increase the body weight.The results from the present study suggest that the selection for higher body weight does not have any negative consequences for resistance to ammonia.In addition to quantitative genetics,tools from molecular genetics can be applied to selective breeding programs to improve the efficiency of selection for traits with low heritability.展开更多
基金Special Fund for Agro-scientific Research in the Public Interest of China under contract No.200903046Research Foundation of Zhejiang Province,China under contract No.2009C12078+1 种基金National Sparking Plan Project of China under contract No.2010GA700010Taishan Scholar Project of Shandong Province,China
文摘The complete diallel cross design was employed to estimate the genetic parameters of the growth of Japanese flounder （Paralichthys olivaceus）. A total of 60 full-sib families were cultivated and two growth-related traits, body weight （BW） and body length （BL）, were examined at average 2, 3 and 8 months of age respectively, with 1 800 individuals measured in each age group （30 per family）. Based on the additive-dominance-maternal-effect genetic analysis model, the restricted maximum likelihood approach was used to estimate various （co）variance components. The results showed that narrow-sense heritability estimates of BW and BL were respectively： 0.29 ± 0.01 and 0.22 ± 0.02 at 2 months of age, 0.32 ± 0.02 and 0.30 ± 0.04 at 3 months of age, 0.48 ± 0.04 and 0.40 ± 0.05 at 8 months of age; broad-sense heritability estimates were respectively： 0.44 ± 0.02 and 0.54 ± 0.04 at 2 months of age, 0.35 ± 0.01 and 0.36 ± 0.03 at 3 months of age, 0.49 ± 0.03 and 0.45 ± 0.04. All heritabilities were statistically significant （P 0.05）. Additive genetic correlations between BW and BL at 2, 3 and 8 months of age were consistently positive and highly significant （P 0.01）： 0.93 ± 0.02, 0.95 ± 0.03 and 0.92 ± 0.03 respectively. Maternal effect was significant （P 0.05） only at 2 months of age, and was not detected at 3 and 8 months of age. According to the heritability estimates, the mass selection strategy should be efficient for the breeding of Japanese flounder.
基金Qingdao Postdoctoral Science Foundation Funded Project under contract No.Q51201403the National Natural Science Foundation of China under contract Nos 31172402 and 31572616+2 种基金the Scientific and Technological Innovation Project financially supported by Qingdao National Laboratory for Marine Science and Technology under contract No.2015ASKJ02Shandong Provincial Natural Science Foundation of China under contract No.ZR2014CQ001the Taishan Scholar Program for Seed Industry
文摘The inability of Fenneropenaeus chinensis to tolerate low temperatures is of major economic concern in temperate climates,as it reduces their growing season and leads to over-winter mortality.In this study,the heritability of body weight under low grow-out temperature and cold tolerance in F.chinensis were first investigated and estimated using 88 ful-sib families,which might provide crucial information in Chinese fleshy prawn breeding programs.The heritability for body weight under suitable and low temperature of F.chinensis were both moderate（0.158 0±0.307 5 and 0.132 0±0.026 9 respectively）;the large coefficient of variation（approximately 21%） and moderate estimate of heritability for body weight indicated substantial potential for selective breeding.The heritability estimate for cold tolerance was low（0.019 2±0.023 5）,and showed no significant differences from zero（P〉0.05）.A weak genetic correlation between cold tolerance and body weight was also estimated in the present study,also showing no significant differences from zero（P〉0.05）.Thus,more research needs to be conducted on the more accurate heritability estimate of cold tolerance and genetic correlations between traits in F.chinensis to further improve the achievement of breeding goals.
基金This study was supported by the National High-Tech Research and Development Program of China(863)under contract No.2005AA603210the National"948"Foundation of China under contract No.2006-G55(B)+2 种基金the National Natural Science Foundation of China under contract No.30500378the 0pen-end Funds of Jiangsu Key Laboratory of Marine Biotechnology,the Huaihai Institute of Technology under contract No.2006HS004the 0pen-end Funds of Key Laboratory of Aquatic Genetic Resources and Aquacultural Ecosystem of the Ministry of Agriculture of China,Shanghai Fisheries University under contract No.KFT2006-6.
文摘Through exploring the microsatellite primers from the random genome sequences of Chinese shrimp （Fenneropenaeus chinensis）, some microsatellite primers were obtained with rich polymorphic genetic information, and a triplex PCR was established using three primers （RS1101, RS0683 and H081 primers）. By adjusting the final concentration of Mg^2＋, dNTP and primers, and using a touch-town PCR program, the optimum amplification parameters of PCR system were obtained, which could successfully amplify the three primers in a PCR reaction. In the denatured PAGE gel, the amplified DNA fragments of three primers RS1 101,RS0683 and H081 could be easily identified each other. For the triplex PCR system, the PPE （probabilities of paternity exclusion） is 0.967 9,and the DP （discrimination power） is 0.999 327.Using the triplex PCR to test ten individuals of a parentage and their parents, an individual was excluded from the parentage in all of the three microsatellite loci, which might be mixed into the parentage for some unknown reason such as factitious misplay. The triplex PCR will be of great practical value in identifying the parentages of F. chinensis.
基金Supported by the National Natural Science Foundation of China (No. 40476021)the National Key Basic Research Program of China (973 Program) (No. 2006CB400600)the Taishan Scholar Program of Shandong Province, and the Yellow and Bohai Sea Scientific Observation and Experiment Station for Fishery Resources and Environment, Ministry of Agriculture
文摘Anchovy is a key species in the Yellow Sea ecosystem. An accurate estimate of anchovy abundance is vital for the management of the anchovy stock and measurement of the ecosystem response to changes in anchovy abundance. However, the acoustic fish abundance estimate may be biased by 30%-40% if the fat-content induced target strength variation is not taken into account. We measured the monthly variation in the fat content of anchovy (Engraulis japonicus) in the Yellow Sea, and evaluated the potential effect of variation in fat content on the acoustic assessment of anchovy abundance. The fat content of anchovy varied seasonally, with two maxima and two minima in a year. The highest fat content (14.75%) was measured in the pre-spawning period in May, and the lowest fat content (2.48%) was measured during the post-spawning period in October. Fat content appeared to correlate with water content, but not body size. Assuming that the target strength is decreased by 0.2dB for every 1% increase in fat content, the seasonal difference in the target strength of anchovy may be as high as 2.45 dB. Given this, the acoustic abundance estimate may be biased by between 43% and 76%. Our results highlight the need for more information on the changes in fat content of fishes whose abundance is estimated by acoustic surveys.
基金supported by Primary Research&Development Plan of Shandong Province(2016GGF01068)the National Natural Science Foundation of China(Nos.31302193,41676147)+3 种基金Environment and Aquaculture Governance(CHN-2152,13/0033)Public Funds of Key Laboratory of East China Sea&Oceanic Fishery Resources Exploitation and Utilization,Ministry of Agriculture,P.R.China(2013K06)the Special Scientific Research Funds for Central Non-profit Institutes,Yellow Sea Fisheries Research Institutes(20603022015017)National Natural Science Foundation of China 41306117)
文摘The present study investigated the applicability of integrated polychaete-fish culture for fish waste removal to offset negative impact induced by organic benthic enrichment.A field study demonstrated that deposition rate was significantly higher underneath the fish farm than that in control area.The material settling under the farm was characterized by a high amount of fish feces(45%) and uneaten feed(27%).Both feeding rate(FR) and apparent digestibility rate(ADR) increased with decreasing body weight,as was indicated by significantly a higher rate observed for the groups containing smaller individuals in a lab study.The nutrient in fresh deposited material(De) was higher than that in sediments collected under the farm(Se),resulting in lower feces production but higher apparent digestibility rate for the De group as feeding rate was similar.Consequently,higher nutrient removal efficiency was observed in the De group.A mass balance approach indicated that approximately 400–500 individuals m^(-2) is required for removing all waste materials deposited underneath the fish farm,whereas abundance can be lower(about 300–350 individuals m^(-2)) when only the fish waste needs to be removed.The results showed that a significant amount of waste had been accumulated in the fish cages in Sanggou Bay.The integration of fish with P.aibuhitensis seems promising for preventing organic pollution in the sediment and therefore is an effective strategy for mitigating negative effect of fish farms.Thus such integration can become a new IMTA(integrated multi-trophic aquaculture) model in Sanggou Bay.
基金supported by the National Natural Science Foundation of China (Nos.31372523 and 31302180)the Scientific and Technological Innovation Project Financially Supported by Qingdao National Laboratory for Marine Science and Technology (No.2015ASKJ02)+4 种基金the Taishan Scholar Program for Seed Industrythe Shandong Provincial Natural Science Foundation (No.ZR2014CQ001)the Special Fund for Postdoctoral Innovative Project of Shandong ProvinceCentral Public-Interest Scientific Institution Basal Research Fund of the Yellow Sea Fisheries Research Institute (No.20603022015013)the China Agriculture Research System (CARS-48)
文摘In this study,families of selected population for growth(SP_BWT),selected population for white spot syndrome virus(WSSV)resistance(SP_RW),Bohai wild population(WP_BH)and Huanghai wild population(WP_HH)of F.chinensis were constructed through artificial insemination and with the standardized procedure of larvae rearing.Growth and survival performance were studied among four populations after a 70 days common test.The results showed that the maximum least square mean of body weight was 17.50 g in SP_BWT while the minimum was 13.03 g in WP_HH.Compared with WP_BH,body weight of SP_BWT increased by 23.41%(P<0.01)and that of SP_RW by 12.20%(P>0.05).Body weights of SP_BWT and SP_RW were significantly higher than that of WP_HH,which increased by 34.31%(P<0.01)and 22.10%(P<0.05),respectively.The mean AGR of four populations was 0.19,0.18,0.17 and 0.16 g d^(-1),respectively.Coefficient of variation of body weight among four populations was high,which ranged from 32.67% to 35.25%.Such a range showed that there was the potentiality for further improvement in selected populations.Coefficient of variation of survival rate among four populations was low,varying between 3.20% and 5.90%.The difference of survival was highly significant(P<0.01)between SP_BWT and WP_BH,and significant(P<0.05)between SP_RW and WP_BH.However,no significant difference among other populations(P>0.05)was observed.Different growth performances were also observed among different families in each population.The body weight of 798F family was the highest.The absolute growth rate(AGR)was 0.25 g d^(-1),150%higher than that of the lowest one,0.1 g d^(-1) in 807F family.Survival rate of families among four populations was different.The highest was 94.74%,and the lowest was 71.88%.
基金supported by the National Natural Science Foundation of China (No. 31502163)
文摘To investigate the genetic components of growth in the brine shrimp Artemia sinica, we estimated the genetic parameters of body length and the response to selection using a fully pedigreed population of A. sinica. The base population was generated from four wild founder populations. We tested 4160 offspring in 360 families over four generations for growth and survival performance. Across four generations, we produced full-and half-sib families with nested mating, where two dams were mated to the same sire. Individual body length was measured for each nauplius at day 20 post-hatching. Heritability of body length was estimated across four generations with the restricted maximum likelihood method. The heritability of body length in A. sinica was low(0.14 ± 0.05), and the common environmental effect was 0.14 ± 0.02. We estimated the response to selection for body length by calculating the difference in the mean breeding values between different generations. The accumulated genetic gain in body length was 278.94 μm after three generations of selection. This low response to selection was probably caused by the low heritability of body length, small sample size, and the low selection intensity(50%). The results suggest that A. sinica selective breeding programs must be changed to generate any substantial, sustainable genetic increases in body length. We suggest that optimal genetic gains could be achieved by introducing wild strains into the nuclear breeding population to increase genetic variation, and by increasing the size of the breeding population to allow for increased selection intensity.
基金The National High Technology Research and Development Program of China (863 Program) under contract No.2006AA10A401the Taishan Scholar Project of Shandong Province,Chinathe National Natural Science Foundation of China under contract Nos 41006107 and 30972244
文摘Two transcription factors, Sox9a and Foxl2 were cloned from half-smooth tongue sole （Cynoglossus semilaevis）. Sox9a is a new duplication of C.semilaevis Sox9 gene. The complete cDNA of Sox9a gene was 1 842 bp long coding for 487 amino acids and Foxl2 gene was 1 817 bp coding for 308 amino acids. Sox9a was expressed higher in male brain, pituitary and gonad and Foxl2 were higher in female brain, pituitary and gonad. The expression of Sox9a gene in gonads of neo-males was higher than that of normal females. Sox9a and Foxl2 were expressed higher in gastrula stage than in other stages. In the period of sex differentiation, the expression of Sox9a was first going up and then going down and Foxl2 was higher expressed at 37 dph. The highest expressions of Sox9a and Foxl2 genes occurred in nine-month and 12-month old gonad tissues, respectively. Sox9a gene was considered to have inevitable links with sex reversal, sex differentiation and cell differentiation of embryos and formation of spermatogenic ceils. Foxl2 was considered to play a role in sex differentiation, cell differentiation of embryos but not to be necessary for sex determination and sex reversal.
基金The General Program of the National Natural Science Foundation of China under contract No.30871919the National High Technology Research and Development Program of China (863 Program) under contract No.2006AA10A406
文摘An analysis of a selection experiment was used to assess the impact of various animal model struc- tures on REML estimates of variance components. The analyses were carried out based on 162 d body mass （BM） of 1 287 animals from 21 paternal half-sib groups of Fenneropenaeus chinensis. Estimated breeding values （EBV） of BM of all individuals were estimated using eight statistical models （A, AB, ABC, ABDC, ABMFC, ABMDC, ABFDC and ABMFDC） and BLUP （best linear unbiased prediction）. These models were designed involving factors such as sex, spawn date as fixed effects, maternal genetic effects, full-sib family effects as random effects, mean BM of families at tagging and age at recording （covariate）. The results demonstrate the importance of correct interpretation of effects in the data set, particularly those that can influence resemblance between relatives. The data structure and the particular model that was applied markedly influenced the magnitude of variance component estimates. Models based on few effects obtained upward biased estimates of additive genetic variance. The accuracy of genetic parameters and breeding value es- timated by ABFDC model was higher than other models. The results imply that additive genetic direct value, full-sib family effects, and covariance effects besides sex and spawn date as fixed effects were very important for estimating genetic parameters and breeding value of body mass. This model had a heritability estimate of 162 d BM of 0.44. The comparison of the efficiency of selection based on breeding values or phenotypic value revealed great difference： average breeding value of the best 24 families selected by the 162 d BM breeding value and phenotype were 0.577 g and 0.366 g, respectively, representing a 36.57% higher efficiency in the former. In conclusion, selection based on breeding value was more effective than selection based on phenotypic value. Our results indicate that effects influencing the magnitude of estimates should be taken into account when estimating heritability and breeding values for BM.
基金The National Natural Science Foundation of China under contract Nos30700619,40706050 and 40706048the National Key Basic Research Development Plan of China under contract No.2006CB400608+1 种基金the HI-TECH Research and Development Program of China of China under contract No.2006AA10Z414the National Science & Technology Pillar Program under contract No.2006BAD01A13.
文摘A muhispecies model for shellfish polycuhure in the Sanggou Bay in China used for large-scale long-line cultivation of the Chinese scallop Chlamysfarreri, the Pacific oyster Crassostrea gigas and the kelp Laminaria japonica is presented. The model includes key physical processes which are the transports of matter at the system boundary, and the main biological process that is the primary production and nutrients release from the bottom. By the model, the seasonal fluctuations of phytoplankton biomass and dissolved inorganic nitrogen（DIN） in 1994 are simulated. Furthermore, if the kelp culture scale is kept constant and the Chinese scallop and the Pacific oyster culture scales are adjusted, virtual shellfish farms are funded and responses of phytoplankton to the largescale shellfish culture are simulated. According to these simulated results, the room limitation, and the hypothesis that shellfish will not grow well if the phytoplankton biomass is less than 8.2 mg/m^3 , the expandable multiple of scallop culture k and that of oyster culture y are determined as k = -0.276 5y ＋4.690 5 and 0.133 3k ＋0.006 6y≤0.667 5, where, k （ or y） is equal to 1, the culture scale of scallop （ or oyster） is 8.8 x 109 individuals （or 66 ha, with a density of 59 ind./m^2 ）, and the kelp culture scale is 3 300 ha with a density of 12 ind./m^2.
基金The Special Scientific Research Funds for Central Non-profit Institutes,Yellow Sea Fisheries Research Institutes under contract No.20603022012002the National High Technology Research and Development Program of China(863 Program) under contract No.2012AA10A408-7
文摘Twenty-six half-sib groups （53 full-sib families） of turbot,Scophthalmus maximus Linnaeus, were obtained by artificial insemination. We measured growth in the offspring （40-50 individuals/family） and subjected them to a thermal tolerance challenge over a period of 34 d. There was no significant difference in daily mor-tality （range： 0.580%-1.391%） between Days 1-13 during the thermal tolerance challenge. However, daily cumulative mortality increased rapidly between Days 14 and 29, especially on Days 15 and 16 （20.232% and 34.377%, respectively）. Mortality was highest on Day 16 （14.145%）. We estimated the genetic parameters using the average information restricted maximum likelihood method. We used a likelihood ratio test to evaluate the significance of effects in models with and without identity as an effect, and compared the final log-likelihoods （maximum log L）. Lastly, we estimated phenotypic and genetic correlation between the up-per thermal tolerance limit （UTT） and body weight （BW）. In this study, the positive phenotypic correlation was low between UTT and BW （0.093±0.029）. The genetic correlation between UTT and BW was negative （-0.044±0.239）. The heritability for upper thermal tolerance was low （0.087±0.032）, which is of approximate-ly moderate heritability. The heritability for body weight was high （0.303±0.074）. Our results suggest there is significant potential for improvement in the culture of turbot by selective breeding.
基金supported by the National High Technology Development Project of China under contract No. 2012AA10A404the Recommended International Advanced Agricultural Science and Technology Project of China under contract No. 2012-S5
文摘Seven microsatellite markers were used to evaluate the genetic diversity and differentiation of seven stocks of Litopenaeus vannamei, which were introduced from Central and South America to China. All seven microsatellite loci were polymorphic, with polymorphism information content(PIC) values ranging from 0.593 to 0.952. Totally 92 alleles were identified, and the number of alleles(Na) and effective alleles(Ne) varied between 4 and 21 and 2.7 and 14.6, respectively. Observed heterozygosity(Ho) values were lower than the expected heterozygosity(He) values(0.526–0.754), which indicated that the seven stocks possessed a rich genetic diversity. Thirty-seven tests were detected for reasonable significant deviation from Hardy-Weinberg equilibrium. Fis values were positive at five loci, suggesting that there was a relatively high degree of inbreeding within stocks. Pairwise Fst values ranged from 0.0225 to 0.151, and most of the stock pairs were moderately differentiated. Genetic distance and cluster analysis using UPGMA revealed a close genetic relationship of L. vannamei between Pop2 and Pop3. AMOVA indicated that the genetic variation among stocks(11.3%) was much lower than that within stocks(88.7%). Although the seven stocks had a certain degree of genetic differentiation and a rich genetic diversity, there is an increasing risk of decreased performance due to inbreeding in subsequent generations.
基金Supported by the Earmarked Fund for Modern Agro-Industry Technology Research System (No Nycytx-50)National Sustain Plan of China (No2006BAD01A12012)+1 种基金Agriculture Commonweal Scientific Research Plan (NoNyhyzx07-046)the Yellow Sea Fisheries Research Institute Scientific and Research Fund (No 2009-ts-11)
文摘We analyzed the survival data of the offspring from 21 sires and 42 dams of turbot. The results show that the cumulative survival rates for turbot from 2 to 18 months range from 17.5% to 28.5% main mortality occurred during months 2-5; and the highest survival rates of families were 97.9%, 98.8%, 99.4%, 99.7% during months 2-5, 5-6, 6-8, 8-11, and ll-18, respectively, and 99.5%, being 53.5%, 23.8%, 19.5%, 14.9%, and 13.2% higher, respectively, than the mean values in each period. In all periods, the estimated heritabilities for survival were very low without significant difference from zero （P〉0.05） （values ranged from 0.06 to 0.12）, indicating low additive genetic effects. The genetic correlations of survival among families in different periods were all positive, but low in magnitude （values range from 0.03 to 0.31）. Genetic correlations between long-term survival and other periods＇ survival had negative values （-0.06 and -0.15） and three positive values （0.16, 0.12 and 0.14）. Genetic correlations between survival and weight were all positive, except for survival at months 2-5 and weight at 18 months, which was not significantly negative （-0.18）.
基金The National Natural Science Foundation of China under contract Nos 30490233 and 40906086the National Key Basic Research Program from the Ministry of Science and Technology under contract No. 2006CB400608
文摘Taxonomic diversity of fish assemblages in the Changjiang Estuary （Yangtze River Estuary） and its adjacent waters was analyzed based on bottom trawl surveys carried out by R/V Beidou in June, August and October 2006. Four groups of fishes were identified for each survey by the twoway indicator species analysis （TWIA）. Taxonomic distinctness, species richness and phylogenetic diversity were used to detect changes in taxonomic structure of fish assemblages. Most dominant fish species mainly belonged to Perciformes, Pleuronectiformes, Clupeiformes, Scorpaeniformes and Tetraodontiformes. Species richness in offshore waters of the survey area was higher than that in the other area. The average taxonomic distinctness value （AvTD,△^＋） of each fish assemblage was close to the average taxonomic distinctness of master list in the Changjiang Estuary （79.9）, and had a positive correlation with species richness and Shannon diversity index （H′）. A negative correlation was found between variations in taxonomic distinctness （VarTD, A^＋） and traditional diversity indices, which were caused by fish species component that led to longer average path lengths among species. Taxonomic diversity index （△） had the similar results with species richness, Ht, Simpson diversity index （D） and Pielou＇s evenness index （J′）. VarTD also kept stable, which further certificated that fish assemblages and ecological environment were in equilibrium. Taxonomic distinctness index （△^＋） was relatively stable in most of fish assemblages, and had higher values in some fish assemblages for a few absolutely dominant species. The present study showed that fish community formed new equilibrium stability in 2006 in the Changjiang Estuary when compared with those in the corresponding months of annual survey from 1985 to 1986. And AvTD in each sampling station was lower than AvTD of master list in the Changjiang Estuary, so some ecological niches were absent in each sampling stations from taxonomic or phylogenetic relationships, these would be helpful to stock natural resource and maintain ecological equilibruim of fish assemblages.
文摘A mass-balanced model was constructed to determine the flow-energy in a community of fishes and invertebrates in the Beibu Gulf, northern South China Sea using Ecopath and Ecosim software. Input parameters were taken from the literature, except for the biomass of fish groups which was obtained from trawl surveys during October 1997 to May 1999 in the study area. The model consisted of 16 functional groups （boxes）, including one marine mammal and seabirds, each representing organisms with a similar role in the food web, and only covered the main trophic flow in the Beibu Gulf ecosystem. The results showed that the food web of Beibu Gulf was dominated by the detrital path and benthic invertebrates played a significant role in transferring energy from the detritus to higher trophic levels; phytoplankton was a primary producer and most utilized as a food source. Fractional trophic levels ranged from 1.0 to 4.08 with marine mammals occupying the highest trophic level. Using network analysis, the system network was mapped into a linear food chain and six discrete trophic levels were found with a mean transfer efficiency of 16.7% from the detritus, 16.2% from the primary producer within the ecosystem. The biomass density of the commercially utilized species estimated by the model is 8.46 t/km^2, only O. 48% of the net primary production.
基金This project was financially supported by the High Technology Research and Development Program of China (GrantNo.2001AA623030 and No.2003AA623030)
文摘A simulation method based on the lumped mass model is proposed for determining the dynamic behavior of nets exposed to a uniform current. Every mesh bar is modeled by a linear bar clement. The lumped mass point is set at the ends of each element. The net can be simulated by a discretized model consisting of many point masses and elements without mass. 3D shapes and the distribution of tensions of the net at different moments can be found from time integration of a set of motion equations with a computer program. Two nets are simulated according to reference experiments. Calculated results are in accordance with experimental results. The method is applicable and can be applied to improving design of, and research into other flexible structures, such as net cages.
基金Supported by the Key Project of National Natural Science Foundation of China(No.31061160187)the National Basic Research Program of China(973 Program)(No.2010CB951204)+1 种基金Taishan Scholar Program of Shandong ProvinceYellow & Bohai Sea Scientific Observation and Experiment Station for Fishery Resources and Environment,Ministry of Agriculture
文摘The status of fishery stocks in the coastal waters of China is far from ideal, mainly due to climate change and the impacts of human activities （e.g., pollution and overfishing）. Thus, the restoration and protection of fishery resources have become critical and complex. The stability and balanced structure of the fish community is a basic foundation for the protection of fishery resources. Based on data collected from bottom trawls by the R/V Beidou in continental shelf of the East China Sea in November 2006 and February 2007, changes in the composition and diversity of fish species and functional groups were analyzed. The research area was divided into offshore waters and inshore waters by the two-way indicator species analysis （TWIA）. The results showed that the dominant species were different between offshore waters and inshore waters and also varied with the survey time. The most abundant family was Sciaenidae and Teraponidae in November 2006, Sciaenidae, Engraulidae and Triglidae were most abundant in February 2007. The species belonged mainly to mobile piscivores （G6）, benthivores/piscivores （G4）, benthivores （G3） and planktivores （G1）, and the dominant species in November 2006 were commercial species （e.g. Larimichthys polyactis and Trichiurusjaponicus）, but small-sized species were dominant in February 2007 （e.g., Harpadon nehereus, Benthosema pterotum, Champsodon capensis, and Acropoma japonieum）. The species diversity showed a similar trend as the functional group diversity. Stations with higher diversity were mainly distributed in inshore waters in February 2007, whereas higher diversity was found in offshore waters in November 2006. The highest biomass and species number were found in G6 group, followed by the G4, G5 and GI groups. The distribution of the number of individuals of each functional group showed the opposite trend as that of the biomass distribution. In addition, the size spectra were mainly concentrated around 3-29 cm, and the individual number of fish species gradually decreased with the increase in body size, but the relative biomass showed a moderate fluctuation in each size class. These changes showed that species with faster growth rate and earlier maturity age became dominant in continental shelf of the East China Sea. So the variations in biological characteristics of fish should be fully considered in maintaining sustainable utilization of fishery resource.
基金supported by the China-Australia Bilateral Research Program (No. 2010DFA31720)the National Key Technology R&D Program (2012BAD28B05)
文摘Noroviruses (NoVs) are widespread causes of nonbacterial gastroenteritis. Outbreaks of NoVs caused diseases are commonly ascribed to the consumption of contaminated shellfish. The concentration and RNA extraction of NoVs are crucial steps of detecting NoVs in shellfish. This study aimed to select a simple, rapid and highly efficient recovery method of NoVs detection with real-time RT-PCR. Four methods of recovering GI.3 and GII.4 NoVs from spiked digestive tissues of oysters and clams, respectively, were compared, of them, the method involving proteinase K and PEG 8000 was found the most efficient. With this method, 9.3% and 13.1% of GI.3 and GII.4 NoVs were recovered from oysters and 9.6% and 12.3% of GI.3 and GII.4 NoVs were recovered from clams, respectively. This method was further used to detect NoVs in 84 oysters (Crassostrea gigas) and 86 clams (Ruditapes philippinarum) collected from 10 coastal cities in China from Jan. 2011 to Feb. 2012. The NoVs isolation rates were 10.47% of clams (9/86) and 7.14% of oysters (6/84). All the detected NoVs belonged to genotype GII. The NoVs recovery method selected is efficient for NoVs detection in oysters and clams.
基金supported by the Special Fund for Agro-scientific Research in the Public Interest of China(No.2060302201515013)the Scientific and Technological Innovation Project Financially Supported by Qingdao National Laboratory for Marine Science and Technology(No.2015ASKJ02)
文摘The dinoflagellate Prorocentrum minimum,one of the most widespread red tide causing species,affects marine aquaculture and ecosystems worldwide.In this study,ridgetail white prawn Exopalaemon carinicauda were exposed to P.minimum cells(5 × 104 cells mL-1) to investigate its harmful effects on the shrimp.Antioxidant activities and histological changes were used as indicators of health status of the shrimp.In 72 hours,the mortality of E.carinicauda was not affected,but its antioxidant response and histology were statistically different from those of control.Elevated superoxide dismutase(SOD) and glutathione peroxidase(GPX) activities and depressed catalase(CAT) activity were observed in gill;while increased SOD,glutathione S-transferase(GST),CAT activities and modulated GPX activity were observed in hepatopancreas.Thus,antioxidant activities in gill and hepatopancreas seem to respond differentially to harmful alga exposure.Increased malondialdehyde(MDA) content in early a few hours indicates the damage of the antioxidant defense system.Although MDA content recovered to a low level thereafter,a series of histological abnormalities including accumulation or infiltration of hemocytes,tissue lesions and necrosis were discovered in gill and hepatopancreas.Exposure to P.minimum induced sublethal effects on E.carinicauda,including temporary oxidative damage and histological injury.
基金Supported by the National High Technology Research and Development Program of China(863 Program)(No.2012AA10A404)the Qingdao Postdoctoral Science Foundation Funded Project(No.Q51201403)+3 种基金the National Natural Science Foundation of China(Nos.31302179,31172402)the 948 Project from the Ministry of Agriculture of China(No.2015-Z17)the Improved Agricultural Breeds Engineering Project of Shandong Province-the Taishan Scholar Program for seed industry "Multi-Tarits Selective Breeding of New Variety and Its Industrialization"the Fundamental Research Funds for the Yellow Sea Fisheries Research Institute Chinese Academy of Fishery Sciences(No.20603022013011)
文摘Ammonia,toxic to aquaculture organisms,represents a potential problem in aquaculture systems,and the situation is exacerbated in closed and intensive shrimp farming operations,expecially for Litopenaeus vannamei.Assessing the potential for the genetic improvement of resistance to ammonia in L.vannamei requires knowledge of the genetic parameters of this trait.The heritability of resistance to ammonia was estimated using two descriptors in the present study:the survival time(ST) and the survival status at half lethal time(SS_(50)) for each individual under high ammonia challenge.The heritability of ST and SS_(50) were low(0.154 4±0.044 6 and 0.147 5±0.040 0,respectively),but they were both significantly different from zero(P<0.01).Moreover,these two estimates were basically the same and showed no significant differences from each other(P>0.05),suggesting that ST and SS_(50) could be used as suitable indicators for resistance to ammonia.There were also positive phenotypic and genetic correlation between resistance to ammonia and body weight,which means that resistance to ammonia can be enhanced by the improvement of husbandry practices that increase the body weight.The results from the present study suggest that the selection for higher body weight does not have any negative consequences for resistance to ammonia.In addition to quantitative genetics,tools from molecular genetics can be applied to selective breeding programs to improve the efficiency of selection for traits with low heritability.
