With the expansion of urban, industry, and agriculture after World War II, eutrophication firstly emerged as a major water quality threat in small water bodies [1]. As the increasing magnitudes and scales of nutrient ...With the expansion of urban, industry, and agriculture after World War II, eutrophication firstly emerged as a major water quality threat in small water bodies [1]. As the increasing magnitudes and scales of nutrient pollution and habitat alteration, many of the world's large lakes exhibit symptoms of eutrophication, e.g., toxic cyanobacterial blooms, deoxygenation, and habitat loss.展开更多
Aquaculture has made an enormous contribution to the world food production,especially to the sustainable supply of animal proteins.The utility of diverse reproduction strategies in fish,such as the exploiting use of u...Aquaculture has made an enormous contribution to the world food production,especially to the sustainable supply of animal proteins.The utility of diverse reproduction strategies in fish,such as the exploiting use of unisexual gynogenesis,has created a typical case of fish genetic breeding.A number of fish species show substantial sexual dimorphism that is closely linked to multiple economic traits including growth rate and body size,and the efficient development of sex-linked genetic markers and sex control biotechnologies has provided significant approaches to increase the production and value for commercial purposes.Along with the rapid development of genomics and molecular genetic techniques,the genetic basis of sexual dimorphism has been gradually deciphered,and great progress has been made in the mechanisms of fish sex determination and identification of sex-determining genes.This review summarizes the progress to provide some directive and objective thinking for further research in this field.展开更多
Analysis and comparison of Jiaozhou Bay data collected from May 1991 to February 1994 revealed the spatiotemporal variations of the ambient Si(OH) 4∶NO 3 (Si∶N) concentration ratios and the seasonal variations of (S...Analysis and comparison of Jiaozhou Bay data collected from May 1991 to February 1994 revealed the spatiotemporal variations of the ambient Si(OH) 4∶NO 3 (Si∶N) concentration ratios and the seasonal variations of (Si∶N) ratios in Jiaozhou Bay and showed that the Si∶N ratios were < 1 throughout Jiaozhou Bay in spring, autumn, and winter. These results provide further evidence that silicate limits the growth of phytoplankton (i.e. diatoms) in spring, autumn and winter. Moreover, comparison of the spatiotemporal variations of the Si∶N ratio and primary production in Jiaozhou Bay suggested their close relationship. The spatiotemporal pattern of dissolved silicate matched well that of primary production in Jiaozhou Bay. Along with the environmental change of Jiaozhou Bay in the last thirty years, the N and P concentrations tended to rise, whereas Si concentration showed cyclic seasonal variations. With the variation of nutrient Si limiting the primary production in mind, the authors found that the range of values of primary production is divided into three parts: the basic value of Si limited primary production, the extent of Si limited primary production and the critical value of Si limited primary production, which can be calculated for Jiaozhou Bay by Equations (1), (2) and (3), showing that the time of the critical value of Si limitation of phytoplankton growth in Jiaozhou Bay is around November 3 to November 13 in autumn; and that the time of the critical value of Si satisfaction of phytoplankton growth in Jiaozhou Bay is around May 22 to June 7 in spring. Moreover, the calculated critical value of Si satisfactory for phytoplankton growth is 2.15-0.76 μmol/L and the critical value of Si limitation of phytoplankton growth is 1.42-0.36 μmol/L; so that the time period of Si limitation of phytoplankton growth is around November 13 to May 22 in the next year; the time period of Si satisfactory for phytoplankton growth is around June 7 to November 3. This result also explains why critical values of nutrient展开更多
Analysis and comparison of Jiaozhou Bay data collected from May 1991 to February 1994(12 seasonal investigations) provided by the Ecological Station of Jiaozhou Bay revealed the characteristic spatiotemporal variation...Analysis and comparison of Jiaozhou Bay data collected from May 1991 to February 1994(12 seasonal investigations) provided by the Ecological Station of Jiaozhou Bay revealed the characteristic spatiotemporal variation of the ambient concentration Si:DIN and Si:16P ratios and the seasonal variation of Jiaozhou Bay Si:DIN and Si:16P ratios showing that the Si:DIN ratios were < 1 throughout the year in Jiaozhou Bay; and that the Si:16P ratios were < 1 throughout Jiaozhou Bay in spring, autumn and winter. The results proved that silicate limited phytoplankton growth in spring, autumn and winter in Jiaozhou Bay. Analysis of the Si:DIN and Si:P ratios showed that the nutrient Si has been limiting the growth of phytoplankton throughout the year in some Jiaozhou Bay waters; and that the silicate deficiency changed the phytoplankton assemblage structure. Analysis of discontinuous 1962 to 1998 nutrient data showed that there was no N or P limitation of phytoplankton growth in that period. The authors consider that the annual cyclic change of silicate limits phytoplankton growth in spring, autumn and winter every year in Jiaozhou Bay; and that in many Jiaozhou Bay waters where the phytoplankton as the predominant species need a great amount of silicate, analysis of the nutrients N or P limitation of phytoplankton growth relying only on the N and P nutrients and DIN:P ratio could yield inaccurate conclusions. The results obtained by applying the rules of absolute and relative limitation fully support this view. The authors consider that the main function of nutrient silicon is to regulate and control the mechanism of the phytoplankton growth process in the ecological system in estuaries, bays and the sea. The authors consider that according to the evolution theory of Darwin, continuous environmental pressure gradually changes the phytoplankton assemblage's structure and the physiology of diatoms. Diatoms requiring a great deal of silicon either constantly decrease or reduce their requirement for silicon. This will cause 展开更多
Chinese mitten crab （Eriocheir sinensis） has higher commercial value as food source than any other species of Eriocheir in China. To evaluate the germplasm resources and characterize the genetic diversity and popula...Chinese mitten crab （Eriocheir sinensis） has higher commercial value as food source than any other species of Eriocheir in China. To evaluate the germplasm resources and characterize the genetic diversity and population structure of the crabs in different water systems, two stocks and two farming populations were assessed with 25 polymorphic microsallite loci available in public GenBank. Basic statistics showed that the average observed heterozygosity （Ho） amongst populations ranged from 0.5789 to 0.6824. However, a remarkable presence of inbreeding and heterozygote deficiencies were observed. To analyze population structure, pairwise FST coefficients explained only -10.3% variability from the subdivision of mitten crab populations, the remaining variability stems from the subdivision within subpopulations. Although the four populations had slight differentiation, different allelic frequencies resulted in distinct population structures. Two stocks and one farming population were clustered together to the phylogenetic branch of Yangtze crab, with an approximate membership of 95%. Whereas, another farming population was clustered singly to the phylogenetic branch of the Liaohe crab, with a membership of 97.1%. The tests for individual admixture showed that Yangtze crab had probably been contaminated with individuals from other water systems. Genetic relationships between populations also supported the conclusion that Yangtze crab and Liaohe crab had different gene pools in spite of the origins of the same species.展开更多
We examined the scale impacts on spatial hot and cold spots of CPUE for Ommastrephes bartramii in the northwest Pacific Ocean. The original fishery data were tessellated to 18 spatial scales from 5′×5′ to 90′&...We examined the scale impacts on spatial hot and cold spots of CPUE for Ommastrephes bartramii in the northwest Pacific Ocean. The original fishery data were tessellated to 18 spatial scales from 5′×5′ to 90′×90′ with a scale interval of 5′ to identify the local clusters. The changes in location, boundaries, and statistics regarding the Getis-Ord Gi＊ hot and cold spots in response to the spatial scales were analyzed in detail. Several statistics including Min, mean, Max, SD, CV, skewness, kurtosis, first quartile（Q1）, median, third quartile（Q3）, area and centroid were calculated for spatial hot and cold spots. Scaling impacts were examined for the selected statistics using linear, logarithmic, exponential, power law and polynomial functions. Clear scaling relations were identified for Max, SD and kurtosis for both hot and cold spots. For the remaining statistics, either a difference of scale impacts was found between the two clusters, or no clear scaling relation was identified. Spatial scales coarser than 30′ are not recommended to identify the local spatial patterns of fisheries because the boundary and locations of hot and cold spots at a coarser scale are significantly different from those at the original scale.展开更多
The neon flying squid （Ommastrephes bartramii） is a short-lived opporttmistic species widely distributed in subtropical and temperate waters in the North Pacific Ocean. The life cycle of O. bartramii from planktonic...The neon flying squid （Ommastrephes bartramii） is a short-lived opporttmistic species widely distributed in subtropical and temperate waters in the North Pacific Ocean. The life cycle of O. bartramii from planktonic eggs to nektonic adults is closely linked to oceanographic conditions. The fluctuations in O. bartramii abundance and distribution tend to increase and widen continu- ously due to the heavy influences of ocean-climate events on various spatio-temporal scales. In this study, we reviewed the interac- tion between O. bartramii and oceanography variability in the North Pacific with respect to large-scale climatic-oceanic phenomena including E1 Nifio, La Nifia, Kuroshio, Oyashio and Pacific Decadal Oscillation （PDO）, as well as regional environmental variables such as sea surface temperature （SST）, sea surface height （SSH）, sea surface salinity （SSS）, chlorophyll-a （Chl-a） concentration, and plankton density. The population dynamics of O. bartramii is mediated mainly by meso- and large-scale climatic-oceanic events （e.g., Kuroshio and Oyashio Currents） rather than other local environmental conditions （e.g., SST and Chl-a concentration）, because all of the oceanographic influences are imposed on the context of large-scale climate changes （e.g., PDO）. An unstructured-grid finite- volume coastal ocean model coupled with an individual-based model is proposed to simulate relevant physical-biological oceano- graphic processes for identifying ocean-climate influence and predicting O. bartramii distribution and abundance in the North Pacific. Future research needs to be focused on improving the knowledge about early life history of O. bartramii and evaluating the relation- ship between marine physical environment and two separate passive drifting life stages of O. bartramii including free-floating eggs and planktonic paralarvae.展开更多
AIM To study the cell types,localization,distribution density and morphology of APUDcells in the intestinal mucosa of stomachlessteleost fishes.METHOD By using the peroxidase-antiperoxidase complex(PAP)immunocytochemi...AIM To study the cell types,localization,distribution density and morphology of APUDcells in the intestinal mucosa of stomachlessteleost fishes.METHOD By using the peroxidase-antiperoxidase complex(PAP)immunocytochemical staining technique theidentification,localization and morphology ofimmunoreactive(IR)endocrine cells seattered inthe intestinal mucosa of grass carp(Cyenopharyngodon idellus),black carp(Mylopharyngodon piceus)and common carp(Cyprinus carpio)were investigated with 20kinds of antisera prepared against mammalianpeptide hormones of APUD cells,and likewise byusing avidin-biotin-peroxidase complex(ABC)method those of silver carp(Hypophthalmichthys molitrix),bighead(Aristichthys nobilis),silver crucian carp(Carassius gibelio)and bluntnose black bream(Megalobrama amblyocephala)were alsostudied with 5 different antisera.Thereplacement of the first antiserum by phosphatebuffered saline(PBS)was employed as a control.IR endocrine cells were counted with asquare-mesh ocular micrometer from 10 fieldsselected randomly in every section of each partof the intestine specimen.The average numberof IR endocrine cells per mm2 was counted toquantify their distribution density.RESULT Gastrin(GAS)-,Gastric inhibitorypeptide(GIP)-,glucagon(GLU)-,glucagon-likeimmunoreactants(GLI)-,bovine pancreaticpolypeptide(BPP)-,leucine-enkephalin(ENK)-and substance P(SP)-IR endocrine cells werefound in the gut of grass carp,black carp andcommon carp,and somatostatin(SOM)-IRendocrine cells were only seen in common carp.GAS-,GIP-and GLU-IR endocrine cells werefound in the intestinal mucosa of silver carp,bighead,silver crucian carp and bluntnose blackbream.Most of IR endocrine cells had the higherdistribution density in the foregut and midgut,and were longer in shape.They had a long apicalcytoplasmic process extended to the gut lumenand a basal process extended to adjacent cellsor basement membrane and touched with it.Sometimes,the basal cytoplasmic processformed an enlarged synapse-like structure in thecontiguous part with basement memb展开更多
Fishery-independent surveys are often used for collecting high quality biological and ecological data to support fisheries management. A careful optimization of fishery-independent survey design is necessary to improv...Fishery-independent surveys are often used for collecting high quality biological and ecological data to support fisheries management. A careful optimization of fishery-independent survey design is necessary to improve the precision of survey estimates with cost-effective sampling efforts. We developed a simulation approach to evaluate and optimize the stratification scheme for a fishery-independent survey with multiple goals including estimation of abundance indices of individual species and species diversity indices. We compared the performances of the sampling designs with different stratification schemes for different goals over different months. Gains in precision of survey estimates from the stratification schemes were acquired compared to simple random sampling design for most indices. The stratification scheme with five strata performed the best. This study showed that the loss of precision of survey estimates due to the reduction of sampling efforts could be compensated by improved stratification schemes, which would reduce the cost and negative impacts of survey trawling on those species with low abundance in the fishery-independent survey. This study also suggests that optimization of a survey design differed with different survey objectives. A post-survey analysis can improve the stratification scheme of fishery-independent survey designs.展开更多
Due to increasing safety concerns regarding human consumption of fish products, an increasing number of medicinal chemicals are prohibited from use in aquaculture. As a result, Chinese herbal medicines are being incre...Due to increasing safety concerns regarding human consumption of fish products, an increasing number of medicinal chemicals are prohibited from use in aquaculture. As a result, Chinese herbal medicines are being increasingly used, coining the use of the term ＂green medicine.＂ Research shows that Chinese herbal medicines have many beneficial effects on fish, including growth promotion, enhancement of disease resistance, and improvement in meat quality. Many effective ingredients have been discovered in Chinese herbal medicines, which function to promote feed intake, improve meat flavor, and increase digestive enzyme activity. They also regulate and participate in processes that improve the specific and non-specific immunity of fish; however, the composition of Chinese herbal medicines is very complex and it is often difficult to identify the effective ingredients. This article reviews the latest research and application progress in Chinese herbal medicines regarding growth and feed utilization, immunity and disease resistance, and the meat quality of cultured fish. It also discusses research on the chemical constituents of classical Chinese medicinal herbs and problems with the application of Chinese herbal medicines in fish culture. This article concludes by proposing that future studies on Chinese herbal medicines should focus on how to cheaply refine and extract the effective ingredients in classical Chinese medicinal herbs, as well as how to use them efficiently in aquaculture.展开更多
Aquatic viruses include infected viruses in aquatic animals, plants and microorganisms, and free-floating viruses(virioplankton)in water environments. In the last three decades, a huge number of aquatic viruses, espec...Aquatic viruses include infected viruses in aquatic animals, plants and microorganisms, and free-floating viruses(virioplankton)in water environments. In the last three decades, a huge number of aquatic viruses, especially diverse free-floating viruses,including cyanophages, phycoviruses, archaea viruses, giant viruses, and even virophages, have been identified by virological experiments and metagenomic analyses. Based on a comprehensive introduction of aquatic virus classification and their morphological and genetic diversity, here, we summarize and outline main virus species, their evolutionary contribution to aquatic communities through horizontal gene transfer, and their ecological roles for cyanobacterial bloom termination and global biogeochemical cycling in freshwater and marine ecosystems. Thereby, some novel insights of aquatic viruses and virus-host interactions, especially their evolutionary contribution and ecological rolesin diverse aquatic communities and ecosystems, are highlighted in this review.展开更多
Polyploidization is a major driver of speciation and its importance to plant evolution has been well recognized.Bamboos comprise one diploid herbaceous and three polyploid woody lineages,and are members of the only ma...Polyploidization is a major driver of speciation and its importance to plant evolution has been well recognized.Bamboos comprise one diploid herbaceous and three polyploid woody lineages,and are members of the only major subfamily in grasses that diversified in forests,with the woody members having a tree-like lignified culm.In this study,we generated four draft genome assemblies of major bamboo lineages with three different ploidy levels(diploid,tetraploid,and hexaploid).We also constructed a high-density genetic linkage map for a hexaploid species of bamboo,and used a linkage-map-based strategy for genome assembly and identification of subgenomes in polyploids.Further phylogenomic analyses using a large dataset of syntenic genes with expected copies based on ploidy levels revealed that woody bamboos originated subsequent to the divergence of the herbaceous bamboo lineage,and experienced complex reticulate evolution through three independent allopolyploid events involving four extinct diploid ancestors.A shared but distinct subgenome was identified in all polyploid forms,and the progenitor of this subgenome could have been critical in ancient polyploidizations and the origin of woody bamboos.Important genetic clues to the unique flowering behavior and woody trait in bamboos were also found.Taken together,our study provides significant insights into ancient reticulate evolution at the subgenome level in the absence of extant donor species,and offers a potential model scenario for broad-scale study of angiosperm origination by allopolyploidization.展开更多
AIM To identify the type localization andmorphology of APUD endocrine cells in thegastroenteropancreatic(GEP)system ofstomach-containing teleosts,and study APUDendocrine system in the stomach,intestine andpancreas of ...AIM To identify the type localization andmorphology of APUD endocrine cells in thegastroenteropancreatic(GEP)system ofstomach-containing teleosts,and study APUDendocrine system in the stomach,intestine andpancreas of fish species.METHODS Two kinds of immunocytochemical(ICC)techniques of the streptavidin biotin-peroxidase complex(SABC)and streptavidin-peroxidase(S-P)method were used.Theidentification,localization and morphology ofAPUD endocrine cells scattered in the mucosa ofdigestive tract,intermuscular nerve plexus andglandular body of northern snakehead(Channaargus),ricefield eel(Monopterus albus),yellow catfish(Pelteobagrus fulvidraco),mandarinfish(Siniperca chuatsi),largemouthbass(Micropterus salmoides),orientalsheatfish(Silurus asotus),freshwater pomfret(Colossoma brachypomum)and nile tilapia(Tilapia nilotica)were investigated with 8 kindsof antisera.RESULTS The positive reaction of 5-hydroxytryptamine(5-HT)immunoreactiveendocrine(IRE)cells was found in the digestive tract and glandular body of 8 fish species indifferent degree.Only a few gastrin(GAS)-IREcells were seen in C.argus,M.albus and P.fulvidraco.Glucagon(GLU)-IRE cells were notfound in the digestive tract and glandular bodybut existed in pancreatic island of most fishspecies.The positive reaction of growthhormone(GH)-IRE cells was found only inpancreatic island of S.Chuatsi and S.Asotus,no positive reaction in the other 6 fish species.Somatostatin(SOM)-,calcitonin(CAL)-,neurofilament(NF)-and insulin(INS)-IRE cellsin the stomach,intestine and pancreas of 8 kindsof fish were different in distribution and types.The distribution of all 8 APUD cells was the mostin gastrointestinal epithelium mucosa and then indigestive glands.The positive reaction of SOM-and 5-HT-IRE cells was found in intermuscularnerve plexus of intestine of P.fulvidraco andS.chuatsi.Only GH-IRE cells were denselyscattered in the pancreatic islands of S.chuatsiand S.asotus,and odd distribution in thepancreas of S.asotus,SOM-IRE cells weredistributed in the pancreatic islands of S.aso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
Age, maturation and population structure of the Humboldt squid Dosidicus gigas were studied based on random sampling of the Chinese jigging fishery off the Peruvian Exclusive Economic Zones （EEZ） during 2008-2010. E...Age, maturation and population structure of the Humboldt squid Dosidicus gigas were studied based on random sampling of the Chinese jigging fishery off the Peruvian Exclusive Economic Zones （EEZ） during 2008-2010. Estimated ages ranged from 144 to 633 days, confirming that the squid is a short-lived species with longevity no longer than 2 years. Occurrence of mature females and hatching in each month indicated that Humboldt squid spawned year-round. Back-calculated hatching dates for the samples were from January 22^nd, 2008 to April 22nd, 2010 with a peak between January and March. Two size-based and two hatching date-based populations could be defined from mantle length （ML） at maturity and back-calculated hatching dates, respectively. Females matured at a larger size than males, and there was a significant difference in ML at maturity between the two hatching groups （P〈0.05）. The waters adjacent to 1 l^S off the Peruvian EEZ may be a potential spawning ground. This study shows the complexity of the population structure and large variability in key life history parameters in the Humboldt squid off the Peruvian EEZ, which should be considered in the assessment and management of this important resource.展开更多
The hydrodynamic forces and flow field of artificial reef models in steady flow were numerically investigated using the RNG κ-ε turbulent model. The numerical simulation results are consistent with results observed ...The hydrodynamic forces and flow field of artificial reef models in steady flow were numerically investigated using the RNG κ-ε turbulent model. The numerical simulation results are consistent with results observed by experimental means. A comparative study indicates that the corresponding errors of forces between calculated values and values observed in the experiment vary in the range of2.3%-11.2% and that the corresponding errors of velocities vary in the range of 1.3%-15.8%. The flow field numerical results show that upstream and vortices exist when the current passes over and through the surface of the reef model. This study suggests that the numerical simulation method can be applied to predict the forces and flow field associated with artificial reefs.展开更多
Length frequency data of small yellow croaker （Larimichthys polyactis） were acquired from the survey vessel in May, July, September and December, 2011 in Haizhou Bay of China. In this study, 921 fish individuals wer...Length frequency data of small yellow croaker （Larimichthys polyactis） were acquired from the survey vessel in May, July, September and December, 2011 in Haizhou Bay of China. In this study, 921 fish individuals were analyzed for the estimation of growth and mortality parameters. Between length and weight, the power coefficient b was 2.7321, 2.9703, 3.0418 and 2.7252 for the 4 surveying months, respectively. The estimated von Bertalanffy growth function parameters were 230mm （L∞） and 0.26yr-1 （K） as were calculated with ELEFAN method equipped in FiSAT computer package. With length-converted catch curve analysis, the total mortality rate （Z） and its 95% confidence interval were 2.16 （1.69-2.64） yr-1, 0.59 （0.15-1.04） yr-1, 1.16 （0.80-1.52） yrl and 0.96 （0.70-1.23） yr1 for the 4 surveying months, respectively, with the pooled data the value was 1.15 （0.81-1.48） yr1. The natural mor- tality rate （M） was 0.516 yr 1 as was calculated with Pauly＇s equation （the annual average sea water temperature was 11 ℃）. Therefore, fish mortality rate was 0.634 yrz. The yield-per-recruit analysis indicated that when tc was 1, Fmax, was 0.7 and F01 was 0.55. Cur- rently, the age at first capture is about 1 year and Fcurrent was 0.634. Therefore, Fcurrent was larger than F0.1 and less than Fmax. This indicates that current fish mortality is at a dangerously high level. With Gulland method, the biological reference point for fishery （Fopt） was estimated as 0.516 yr1, lower than current fish mortality. Accordingly, reducing catch in the region was strongly recom- mended.展开更多
Generalized linear models （GLM） and generalized additive models （GAM） were used to standardize catch per unit fishing effort （CPUE） of Ommastrephes bartramii for Chinese squid-jigging fishery in Northwest Pacifi...Generalized linear models （GLM） and generalized additive models （GAM） were used to standardize catch per unit fishing effort （CPUE） of Ommastrephes bartramii for Chinese squid-jigging fishery in Northwest Pacific Ocean. Three groups of variables were considered in the standardization： spatial variables （longitude and latitude）, temporal variables （year and month） and environmental variables, including sea surface temperature （SST）, sea surface salinity （SSS） and sea level height （SLH）. CPUE was treated as the dependent variable and its error distribution was assumed to be log-normal in each model. The model selections of GLM and GAM were based on the finite sample-corrected Akaike information criterion （AICC） and pseudo-coefficient （Pcf） combined P-value, respectively. Both GAM and GLM analysis showed that the month was the most important variable affecting CPUE and could explain 21.3% of variability in CPUE while other variables only explained 8.66%. The interaction of spatial and temporal variables weakly influenced the CPUE. Moreover, spatio-temporal factors may be more important in influencing the CPUE of this squid than environmental variables. The standardized and nominal CPUEs were similar and had the same trends in spatio-temporal distribution, but the standardized CPUE values tended to be smaller than the nominal CPUE. The CPUE tended to have much higher monthly variation than annual variations and their values increased with month. The CPUE became higher with increasing latitude-high CPUE usually occurred in 145°E-148°E and 149°E-162°E. The CPUE was higher when SST was 14-21℃ and the SLH from -22 cm to -18 cm. In this study, GAM tended to be more suitable than GLM in analysis of CPUE.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 estim展开更多
Aquaculture is one of the most efficient modes of animal protein production and plays an important role in global food security.Aquaculture animals exhibit extraordinarily diverse sexual phenotypes and underlying mech...Aquaculture is one of the most efficient modes of animal protein production and plays an important role in global food security.Aquaculture animals exhibit extraordinarily diverse sexual phenotypes and underlying mechanisms,providing an ideal system to perform sex determination research,one of the important areas in life science.Moreover,sex is also one of the most valuable traits because sexual dimorphism in growth,size,and other economic characteristics commonly exist in aquaculture animals.Here,we synthesize current knowledge of sex determination mechanisms,sex chromosome evolution,reproduction strategies,and sexual dimorphism,and also review several approaches for sex control in aquaculture animals,including artificial gynogenesis,application of sex-specific or sex chromosome-linked markers,artificial sex reversal,as well as gene editing.We anticipate that better understanding of sex determination mechanisms and innovation of sex control approaches will facilitate sustainable development of aquaculture.展开更多
基金supported by the National Natural Science Foundations of China(41621002,41661134036)the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences(QYZDJ-SSW-DQC008)+3 种基金the USA National Science Foundation(1240851)MARS Project Funded Under the 7th EU Framework Program(603378)the AU Water Technology Centre(WATEC)the University of Adelaide Environment Institute
文摘With the expansion of urban, industry, and agriculture after World War II, eutrophication firstly emerged as a major water quality threat in small water bodies [1]. As the increasing magnitudes and scales of nutrient pollution and habitat alteration, many of the world's large lakes exhibit symptoms of eutrophication, e.g., toxic cyanobacterial blooms, deoxygenation, and habitat loss.
基金supported by the National Key Basic Research Program(2010CB126301)the Special Fund for Agro-scientific Research in the Public Interest from Ministry of Agriculture of China(2009030406)+1 种基金the Autonomous Project of State Key Laboratory of Freshwater Ecology and Biotechnology(2011FBZ17)the National Natural Science Foundation of China(31301931)
文摘Aquaculture has made an enormous contribution to the world food production,especially to the sustainable supply of animal proteins.The utility of diverse reproduction strategies in fish,such as the exploiting use of unisexual gynogenesis,has created a typical case of fish genetic breeding.A number of fish species show substantial sexual dimorphism that is closely linked to multiple economic traits including growth rate and body size,and the efficient development of sex-linked genetic markers and sex control biotechnologies has provided significant approaches to increase the production and value for commercial purposes.Along with the rapid development of genomics and molecular genetic techniques,the genetic basis of sexual dimorphism has been gradually deciphered,and great progress has been made in the mechanisms of fish sex determination and identification of sex-determining genes.This review summarizes the progress to provide some directive and objective thinking for further research in this field.
文摘Analysis and comparison of Jiaozhou Bay data collected from May 1991 to February 1994 revealed the spatiotemporal variations of the ambient Si(OH) 4∶NO 3 (Si∶N) concentration ratios and the seasonal variations of (Si∶N) ratios in Jiaozhou Bay and showed that the Si∶N ratios were < 1 throughout Jiaozhou Bay in spring, autumn, and winter. These results provide further evidence that silicate limits the growth of phytoplankton (i.e. diatoms) in spring, autumn and winter. Moreover, comparison of the spatiotemporal variations of the Si∶N ratio and primary production in Jiaozhou Bay suggested their close relationship. The spatiotemporal pattern of dissolved silicate matched well that of primary production in Jiaozhou Bay. Along with the environmental change of Jiaozhou Bay in the last thirty years, the N and P concentrations tended to rise, whereas Si concentration showed cyclic seasonal variations. With the variation of nutrient Si limiting the primary production in mind, the authors found that the range of values of primary production is divided into three parts: the basic value of Si limited primary production, the extent of Si limited primary production and the critical value of Si limited primary production, which can be calculated for Jiaozhou Bay by Equations (1), (2) and (3), showing that the time of the critical value of Si limitation of phytoplankton growth in Jiaozhou Bay is around November 3 to November 13 in autumn; and that the time of the critical value of Si satisfaction of phytoplankton growth in Jiaozhou Bay is around May 22 to June 7 in spring. Moreover, the calculated critical value of Si satisfactory for phytoplankton growth is 2.15-0.76 μmol/L and the critical value of Si limitation of phytoplankton growth is 1.42-0.36 μmol/L; so that the time period of Si limitation of phytoplankton growth is around November 13 to May 22 in the next year; the time period of Si satisfactory for phytoplankton growth is around June 7 to November 3. This result also explains why critical values of nutrient
基金funded by the NSFC(No.40036010)subsidized by Special Funds from the National Key BaBic Research Program of P.R.China(G19990437)+2 种基金the Postdoctoral Foundation of Ocean University of Qingdaothe Director’s Foundation of the Beihai Monitoring Center of the State Oceanic Administrationthe Foundation of Shanghai Fisheries University
文摘Analysis and comparison of Jiaozhou Bay data collected from May 1991 to February 1994(12 seasonal investigations) provided by the Ecological Station of Jiaozhou Bay revealed the characteristic spatiotemporal variation of the ambient concentration Si:DIN and Si:16P ratios and the seasonal variation of Jiaozhou Bay Si:DIN and Si:16P ratios showing that the Si:DIN ratios were < 1 throughout the year in Jiaozhou Bay; and that the Si:16P ratios were < 1 throughout Jiaozhou Bay in spring, autumn and winter. The results proved that silicate limited phytoplankton growth in spring, autumn and winter in Jiaozhou Bay. Analysis of the Si:DIN and Si:P ratios showed that the nutrient Si has been limiting the growth of phytoplankton throughout the year in some Jiaozhou Bay waters; and that the silicate deficiency changed the phytoplankton assemblage structure. Analysis of discontinuous 1962 to 1998 nutrient data showed that there was no N or P limitation of phytoplankton growth in that period. The authors consider that the annual cyclic change of silicate limits phytoplankton growth in spring, autumn and winter every year in Jiaozhou Bay; and that in many Jiaozhou Bay waters where the phytoplankton as the predominant species need a great amount of silicate, analysis of the nutrients N or P limitation of phytoplankton growth relying only on the N and P nutrients and DIN:P ratio could yield inaccurate conclusions. The results obtained by applying the rules of absolute and relative limitation fully support this view. The authors consider that the main function of nutrient silicon is to regulate and control the mechanism of the phytoplankton growth process in the ecological system in estuaries, bays and the sea. The authors consider that according to the evolution theory of Darwin, continuous environmental pressure gradually changes the phytoplankton assemblage's structure and the physiology of diatoms. Diatoms requiring a great deal of silicon either constantly decrease or reduce their requirement for silicon. This will cause
文摘Chinese mitten crab （Eriocheir sinensis） has higher commercial value as food source than any other species of Eriocheir in China. To evaluate the germplasm resources and characterize the genetic diversity and population structure of the crabs in different water systems, two stocks and two farming populations were assessed with 25 polymorphic microsallite loci available in public GenBank. Basic statistics showed that the average observed heterozygosity （Ho） amongst populations ranged from 0.5789 to 0.6824. However, a remarkable presence of inbreeding and heterozygote deficiencies were observed. To analyze population structure, pairwise FST coefficients explained only -10.3% variability from the subdivision of mitten crab populations, the remaining variability stems from the subdivision within subpopulations. Although the four populations had slight differentiation, different allelic frequencies resulted in distinct population structures. Two stocks and one farming population were clustered together to the phylogenetic branch of Yangtze crab, with an approximate membership of 95%. Whereas, another farming population was clustered singly to the phylogenetic branch of the Liaohe crab, with a membership of 97.1%. The tests for individual admixture showed that Yangtze crab had probably been contaminated with individuals from other water systems. Genetic relationships between populations also supported the conclusion that Yangtze crab and Liaohe crab had different gene pools in spite of the origins of the same species.
基金The National Natural Science Foundation of China under contract No.41406146the Open Fund from Laboratory for Marine Fisheries Science and Food Production Processes at Qingdao National Laboratory for Marine Science and Technology of China under contract No.2017-1A02Shanghai Universities First-class Disciplines Project-Fisheries(A)
文摘We examined the scale impacts on spatial hot and cold spots of CPUE for Ommastrephes bartramii in the northwest Pacific Ocean. The original fishery data were tessellated to 18 spatial scales from 5′×5′ to 90′×90′ with a scale interval of 5′ to identify the local clusters. The changes in location, boundaries, and statistics regarding the Getis-Ord Gi＊ hot and cold spots in response to the spatial scales were analyzed in detail. Several statistics including Min, mean, Max, SD, CV, skewness, kurtosis, first quartile（Q1）, median, third quartile（Q3）, area and centroid were calculated for spatial hot and cold spots. Scaling impacts were examined for the selected statistics using linear, logarithmic, exponential, power law and polynomial functions. Clear scaling relations were identified for Max, SD and kurtosis for both hot and cold spots. For the remaining statistics, either a difference of scale impacts was found between the two clusters, or no clear scaling relation was identified. Spatial scales coarser than 30′ are not recommended to identify the local spatial patterns of fisheries because the boundary and locations of hot and cold spots at a coarser scale are significantly different from those at the original scale.
基金financially supported by the National High-Tech R&D Program(863 Program)of China(2012AA092303)the Project of Shanghai Science and Technology Innovation(12231203900)+3 种基金the Industrialization Program of National Development and Reform Commission(2159999)the National Key Technologies R&D Program of China(2013BAD13B00)the Shanghai Universities First-Class Disciplines Project(Fisheries A)the Funding Program for Outstanding Dissertations in Shanghai Ocean University
文摘The neon flying squid （Ommastrephes bartramii） is a short-lived opporttmistic species widely distributed in subtropical and temperate waters in the North Pacific Ocean. The life cycle of O. bartramii from planktonic eggs to nektonic adults is closely linked to oceanographic conditions. The fluctuations in O. bartramii abundance and distribution tend to increase and widen continu- ously due to the heavy influences of ocean-climate events on various spatio-temporal scales. In this study, we reviewed the interac- tion between O. bartramii and oceanography variability in the North Pacific with respect to large-scale climatic-oceanic phenomena including E1 Nifio, La Nifia, Kuroshio, Oyashio and Pacific Decadal Oscillation （PDO）, as well as regional environmental variables such as sea surface temperature （SST）, sea surface height （SSH）, sea surface salinity （SSS）, chlorophyll-a （Chl-a） concentration, and plankton density. The population dynamics of O. bartramii is mediated mainly by meso- and large-scale climatic-oceanic events （e.g., Kuroshio and Oyashio Currents） rather than other local environmental conditions （e.g., SST and Chl-a concentration）, because all of the oceanographic influences are imposed on the context of large-scale climate changes （e.g., PDO）. An unstructured-grid finite- volume coastal ocean model coupled with an individual-based model is proposed to simulate relevant physical-biological oceano- graphic processes for identifying ocean-climate influence and predicting O. bartramii distribution and abundance in the North Pacific. Future research needs to be focused on improving the knowledge about early life history of O. bartramii and evaluating the relation- ship between marine physical environment and two separate passive drifting life stages of O. bartramii including free-floating eggs and planktonic paralarvae.
基金the National Natural Science Foundation of China.No.39070666.
文摘AIM To study the cell types,localization,distribution density and morphology of APUDcells in the intestinal mucosa of stomachlessteleost fishes.METHOD By using the peroxidase-antiperoxidase complex(PAP)immunocytochemical staining technique theidentification,localization and morphology ofimmunoreactive(IR)endocrine cells seattered inthe intestinal mucosa of grass carp(Cyenopharyngodon idellus),black carp(Mylopharyngodon piceus)and common carp(Cyprinus carpio)were investigated with 20kinds of antisera prepared against mammalianpeptide hormones of APUD cells,and likewise byusing avidin-biotin-peroxidase complex(ABC)method those of silver carp(Hypophthalmichthys molitrix),bighead(Aristichthys nobilis),silver crucian carp(Carassius gibelio)and bluntnose black bream(Megalobrama amblyocephala)were alsostudied with 5 different antisera.Thereplacement of the first antiserum by phosphatebuffered saline(PBS)was employed as a control.IR endocrine cells were counted with asquare-mesh ocular micrometer from 10 fieldsselected randomly in every section of each partof the intestine specimen.The average numberof IR endocrine cells per mm2 was counted toquantify their distribution density.RESULT Gastrin(GAS)-,Gastric inhibitorypeptide(GIP)-,glucagon(GLU)-,glucagon-likeimmunoreactants(GLI)-,bovine pancreaticpolypeptide(BPP)-,leucine-enkephalin(ENK)-and substance P(SP)-IR endocrine cells werefound in the gut of grass carp,black carp andcommon carp,and somatostatin(SOM)-IRendocrine cells were only seen in common carp.GAS-,GIP-and GLU-IR endocrine cells werefound in the intestinal mucosa of silver carp,bighead,silver crucian carp and bluntnose blackbream.Most of IR endocrine cells had the higherdistribution density in the foregut and midgut,and were longer in shape.They had a long apicalcytoplasmic process extended to the gut lumenand a basal process extended to adjacent cellsor basement membrane and touched with it.Sometimes,the basal cytoplasmic processformed an enlarged synapse-like structure in thecontiguous part with basement memb
基金The Public Science and Technology Research Funds Projects of Ocean under contract No.201305030the Specialized Research Fund for the Doctoral Program of Higher Education under contract No.20120132130001
文摘Fishery-independent surveys are often used for collecting high quality biological and ecological data to support fisheries management. A careful optimization of fishery-independent survey design is necessary to improve the precision of survey estimates with cost-effective sampling efforts. We developed a simulation approach to evaluate and optimize the stratification scheme for a fishery-independent survey with multiple goals including estimation of abundance indices of individual species and species diversity indices. We compared the performances of the sampling designs with different stratification schemes for different goals over different months. Gains in precision of survey estimates from the stratification schemes were acquired compared to simple random sampling design for most indices. The stratification scheme with five strata performed the best. This study showed that the loss of precision of survey estimates due to the reduction of sampling efforts could be compensated by improved stratification schemes, which would reduce the cost and negative impacts of survey trawling on those species with low abundance in the fishery-independent survey. This study also suggests that optimization of a survey design differed with different survey objectives. A post-survey analysis can improve the stratification scheme of fishery-independent survey designs.
文摘Due to increasing safety concerns regarding human consumption of fish products, an increasing number of medicinal chemicals are prohibited from use in aquaculture. As a result, Chinese herbal medicines are being increasingly used, coining the use of the term ＂green medicine.＂ Research shows that Chinese herbal medicines have many beneficial effects on fish, including growth promotion, enhancement of disease resistance, and improvement in meat quality. Many effective ingredients have been discovered in Chinese herbal medicines, which function to promote feed intake, improve meat flavor, and increase digestive enzyme activity. They also regulate and participate in processes that improve the specific and non-specific immunity of fish; however, the composition of Chinese herbal medicines is very complex and it is often difficult to identify the effective ingredients. This article reviews the latest research and application progress in Chinese herbal medicines regarding growth and feed utilization, immunity and disease resistance, and the meat quality of cultured fish. It also discusses research on the chemical constituents of classical Chinese medicinal herbs and problems with the application of Chinese herbal medicines in fish culture. This article concludes by proposing that future studies on Chinese herbal medicines should focus on how to cheaply refine and extract the effective ingredients in classical Chinese medicinal herbs, as well as how to use them efficiently in aquaculture.
基金supported by grants from the National Natural Science Foundation of China (31430091, 31772890)the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA08030202)
文摘Aquatic viruses include infected viruses in aquatic animals, plants and microorganisms, and free-floating viruses(virioplankton)in water environments. In the last three decades, a huge number of aquatic viruses, especially diverse free-floating viruses,including cyanophages, phycoviruses, archaea viruses, giant viruses, and even virophages, have been identified by virological experiments and metagenomic analyses. Based on a comprehensive introduction of aquatic virus classification and their morphological and genetic diversity, here, we summarize and outline main virus species, their evolutionary contribution to aquatic communities through horizontal gene transfer, and their ecological roles for cyanobacterial bloom termination and global biogeochemical cycling in freshwater and marine ecosystems. Thereby, some novel insights of aquatic viruses and virus-host interactions, especially their evolutionary contribution and ecological rolesin diverse aquatic communities and ecosystems, are highlighted in this review.
基金funding from Strategic Priority Program of the Chinese Academy of Sciences(CAS)(XDB31000000 to D.-Z.L)the National Natural Science Foundation of China(grants 31430011 to D.-Z.L.and 31670227 to Z.-H.G.)+3 种基金Leading Talents Program of Yunnan Province(2017HA014 to D.-Z.L.)CAS Youth Innovation Promotion Association(2015321 to P.-F.M.)a grant from Germplasm Bank of Wild Species(Y77P4412Z1 to Z.-H.G.)CAS Pioneer Hundred Talents Program(292015312D11035 to J.-Y.H.).
文摘Polyploidization is a major driver of speciation and its importance to plant evolution has been well recognized.Bamboos comprise one diploid herbaceous and three polyploid woody lineages,and are members of the only major subfamily in grasses that diversified in forests,with the woody members having a tree-like lignified culm.In this study,we generated four draft genome assemblies of major bamboo lineages with three different ploidy levels(diploid,tetraploid,and hexaploid).We also constructed a high-density genetic linkage map for a hexaploid species of bamboo,and used a linkage-map-based strategy for genome assembly and identification of subgenomes in polyploids.Further phylogenomic analyses using a large dataset of syntenic genes with expected copies based on ploidy levels revealed that woody bamboos originated subsequent to the divergence of the herbaceous bamboo lineage,and experienced complex reticulate evolution through three independent allopolyploid events involving four extinct diploid ancestors.A shared but distinct subgenome was identified in all polyploid forms,and the progenitor of this subgenome could have been critical in ancient polyploidizations and the origin of woody bamboos.Important genetic clues to the unique flowering behavior and woody trait in bamboos were also found.Taken together,our study provides significant insights into ancient reticulate evolution at the subgenome level in the absence of extant donor species,and offers a potential model scenario for broad-scale study of angiosperm origination by allopolyploidization.
基金the National Natural Science Foundation of China,No.39470554
文摘AIM To identify the type localization andmorphology of APUD endocrine cells in thegastroenteropancreatic(GEP)system ofstomach-containing teleosts,and study APUDendocrine system in the stomach,intestine andpancreas of fish species.METHODS Two kinds of immunocytochemical(ICC)techniques of the streptavidin biotin-peroxidase complex(SABC)and streptavidin-peroxidase(S-P)method were used.Theidentification,localization and morphology ofAPUD endocrine cells scattered in the mucosa ofdigestive tract,intermuscular nerve plexus andglandular body of northern snakehead(Channaargus),ricefield eel(Monopterus albus),yellow catfish(Pelteobagrus fulvidraco),mandarinfish(Siniperca chuatsi),largemouthbass(Micropterus salmoides),orientalsheatfish(Silurus asotus),freshwater pomfret(Colossoma brachypomum)and nile tilapia(Tilapia nilotica)were investigated with 8 kindsof antisera.RESULTS The positive reaction of 5-hydroxytryptamine(5-HT)immunoreactiveendocrine(IRE)cells was found in the digestive tract and glandular body of 8 fish species indifferent degree.Only a few gastrin(GAS)-IREcells were seen in C.argus,M.albus and P.fulvidraco.Glucagon(GLU)-IRE cells were notfound in the digestive tract and glandular bodybut existed in pancreatic island of most fishspecies.The positive reaction of growthhormone(GH)-IRE cells was found only inpancreatic island of S.Chuatsi and S.Asotus,no positive reaction in the other 6 fish species.Somatostatin(SOM)-,calcitonin(CAL)-,neurofilament(NF)-and insulin(INS)-IRE cellsin the stomach,intestine and pancreas of 8 kindsof fish were different in distribution and types.The distribution of all 8 APUD cells was the mostin gastrointestinal epithelium mucosa and then indigestive glands.The positive reaction of SOM-and 5-HT-IRE cells was found in intermuscularnerve plexus of intestine of P.fulvidraco andS.chuatsi.Only GH-IRE cells were denselyscattered in the pancreatic islands of S.chuatsiand S.asotus,and odd distribution in thepancreas of S.asotus,SOM-IRE cells weredistributed in the pancreatic islands of S.aso
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Supported by the National Natural Science Foundation of China (No.41276156)the National High Technology Research and Development Program of China (863 Program) (No. 2012AA092303)+3 种基金the Innovation Program of Shanghai Municipal Education Commission (No. 13YZ091)Shanghai Leading Academic Disciplin Projectsupported by National Distant-Water Fisheries Engineering Research Center, and Scientific Observing and Experimental Station of Oceanic Fishery Resources, Ministry of AgricultureYong Chen’s involvement in the project was supported by the Shanghai Dongfang Scholar Program
文摘Age, maturation and population structure of the Humboldt squid Dosidicus gigas were studied based on random sampling of the Chinese jigging fishery off the Peruvian Exclusive Economic Zones （EEZ） during 2008-2010. Estimated ages ranged from 144 to 633 days, confirming that the squid is a short-lived species with longevity no longer than 2 years. Occurrence of mature females and hatching in each month indicated that Humboldt squid spawned year-round. Back-calculated hatching dates for the samples were from January 22^nd, 2008 to April 22nd, 2010 with a peak between January and March. Two size-based and two hatching date-based populations could be defined from mantle length （ML） at maturity and back-calculated hatching dates, respectively. Females matured at a larger size than males, and there was a significant difference in ML at maturity between the two hatching groups （P〈0.05）. The waters adjacent to 1 l^S off the Peruvian EEZ may be a potential spawning ground. This study shows the complexity of the population structure and large variability in key life history parameters in the Humboldt squid off the Peruvian EEZ, which should be considered in the assessment and management of this important resource.
基金Supported by the National High Technology Research and Development Program of China(863 Programs)(No.2006AA100301)Science and Technology Development Program of Shandong Province(No.2005GG3205102)
文摘The hydrodynamic forces and flow field of artificial reef models in steady flow were numerically investigated using the RNG κ-ε turbulent model. The numerical simulation results are consistent with results observed by experimental means. A comparative study indicates that the corresponding errors of forces between calculated values and values observed in the experiment vary in the range of2.3%-11.2% and that the corresponding errors of velocities vary in the range of 1.3%-15.8%. The flow field numerical results show that upstream and vortices exist when the current passes over and through the surface of the reef model. This study suggests that the numerical simulation method can be applied to predict the forces and flow field associated with artificial reefs.
基金supported by the Fundamental Research Funds for Central Universities (Grant No. 201022001)
文摘Length frequency data of small yellow croaker （Larimichthys polyactis） were acquired from the survey vessel in May, July, September and December, 2011 in Haizhou Bay of China. In this study, 921 fish individuals were analyzed for the estimation of growth and mortality parameters. Between length and weight, the power coefficient b was 2.7321, 2.9703, 3.0418 and 2.7252 for the 4 surveying months, respectively. The estimated von Bertalanffy growth function parameters were 230mm （L∞） and 0.26yr-1 （K） as were calculated with ELEFAN method equipped in FiSAT computer package. With length-converted catch curve analysis, the total mortality rate （Z） and its 95% confidence interval were 2.16 （1.69-2.64） yr-1, 0.59 （0.15-1.04） yr-1, 1.16 （0.80-1.52） yrl and 0.96 （0.70-1.23） yr1 for the 4 surveying months, respectively, with the pooled data the value was 1.15 （0.81-1.48） yr1. The natural mor- tality rate （M） was 0.516 yr 1 as was calculated with Pauly＇s equation （the annual average sea water temperature was 11 ℃）. Therefore, fish mortality rate was 0.634 yrz. The yield-per-recruit analysis indicated that when tc was 1, Fmax, was 0.7 and F01 was 0.55. Cur- rently, the age at first capture is about 1 year and Fcurrent was 0.634. Therefore, Fcurrent was larger than F0.1 and less than Fmax. This indicates that current fish mortality is at a dangerously high level. With Gulland method, the biological reference point for fishery （Fopt） was estimated as 0.516 yr1, lower than current fish mortality. Accordingly, reducing catch in the region was strongly recom- mended.
基金Supported by the Program for New Century Excellent Talents in University (No.NCET-06-0437)the National High Technology Research and Development Program of China (863 Program) (No.2007AA092201+2 种基金2007AA092202)Shanghai Leading Academic Discipline Project (No.S30702)Doctorship Fund of Shanghai Ocean University (No.06-326)
文摘Generalized linear models （GLM） and generalized additive models （GAM） were used to standardize catch per unit fishing effort （CPUE） of Ommastrephes bartramii for Chinese squid-jigging fishery in Northwest Pacific Ocean. Three groups of variables were considered in the standardization： spatial variables （longitude and latitude）, temporal variables （year and month） and environmental variables, including sea surface temperature （SST）, sea surface salinity （SSS） and sea level height （SLH）. CPUE was treated as the dependent variable and its error distribution was assumed to be log-normal in each model. The model selections of GLM and GAM were based on the finite sample-corrected Akaike information criterion （AICC） and pseudo-coefficient （Pcf） combined P-value, respectively. Both GAM and GLM analysis showed that the month was the most important variable affecting CPUE and could explain 21.3% of variability in CPUE while other variables only explained 8.66%. The interaction of spatial and temporal variables weakly influenced the CPUE. Moreover, spatio-temporal factors may be more important in influencing the CPUE of this squid than environmental variables. The standardized and nominal CPUEs were similar and had the same trends in spatio-temporal distribution, but the standardized CPUE values tended to be smaller than the nominal CPUE. The CPUE tended to have much higher monthly variation than annual variations and their values increased with month. The CPUE became higher with increasing latitude-high CPUE usually occurred in 145°E-148°E and 149°E-162°E. The CPUE was higher when SST was 14-21℃ and the SLH from -22 cm to -18 cm. In this study, GAM tended to be more suitable than GLM in analysis of CPUE.
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 estim
基金supported by the Key Program of Frontier Sciences of the Chinese Academy of Sciences(QYZDY-SSWSMC025)the Strategic Priority Research Program of Chinese Academy of Sciences(XDB31000000)+5 种基金the National Natural Science Foundation of China(31873036,32072958,31922084,31872960,32102789)the National Key Research and Development Project(2018YFD0900204,2018YFD0901201,2018YFD0900203,2018YFD0900201)the Consulting Research Projects of Hubei Institute of Chinese Engineering Development Strategies and Academic Divisions of the Chinese Academy of Sciences(2021-SM02-B-010)the China Agriculture Research System of MOF and MARA(CARS-45-07 and CARS-46)the Autonomous Project of the State Key Laboratory of Freshwater Ecology and Biotechnology(2019FBZ04)the Youth Innovation Promotion Association CAS(2020334)。
文摘Aquaculture is one of the most efficient modes of animal protein production and plays an important role in global food security.Aquaculture animals exhibit extraordinarily diverse sexual phenotypes and underlying mechanisms,providing an ideal system to perform sex determination research,one of the important areas in life science.Moreover,sex is also one of the most valuable traits because sexual dimorphism in growth,size,and other economic characteristics commonly exist in aquaculture animals.Here,we synthesize current knowledge of sex determination mechanisms,sex chromosome evolution,reproduction strategies,and sexual dimorphism,and also review several approaches for sex control in aquaculture animals,including artificial gynogenesis,application of sex-specific or sex chromosome-linked markers,artificial sex reversal,as well as gene editing.We anticipate that better understanding of sex determination mechanisms and innovation of sex control approaches will facilitate sustainable development of aquaculture.
