The diploid chromosome number, karyotype, and DNA content were studied in metaphase chromosome in kidney cells and blood of blue common carp Cyprinus carpio blue var injected with PHA and colchicin by airdrying technique. It was found that the diploid chromosome number was 2n=100. The karyotype was found to be composed of 30 m, 26sm and 44st＋t chromosomes, and NF=156. The diploid nucleus DNA content was measured from the somatic cell of the blue common carp using flow cytometer （Beckman cellLab Quant, made in USA） and the DNA content （2.3 pg· N^＋） in erythrocytes of chick （Gallus sp） as standard. The common carp had DNA content of3.99pg·N^-1, corresponding to the result measured chromosome number as ploidy.

The chromosomes were prepared in the backcross progenies from female hybrids of common carp and crucian carp crossed with male mirror carp and common carp by injection of PHA and colchieines. Results showed that the genome ofbackcross progenies consists of 150 chromosomes which can be divided into four groups according to the centromere site. Each chromosome subgroup is made up of three homologous chromosomes. The chromosome number of the progenies from the female hybrids of common carp and crucian carp crossed with the male common carp is 3 n = 150, the number of chromosome arms 234,and the karyotype formula 3n = 60m ＋ 24sm ＋36st ＋ 30t. The chromosome number of the backcross progenies from female hybrids of common carp and crucian carp crossed with male mirror carp is 3n = 150,the number of chromosome arms 258, and the karvotvoe formula 3n = 63m ＋ 45sm ＋12st ＋30t.

The wild juvenile skin carp Hemibarbus labeo （Pallas） were collected from the YaLu River and Ai River, and cultured in ponds and net cages for 3~4 years until they became broodstocks. A total of 231 females and 231 males were induced to spaw by injection of the hormone （LHRH-A2＋DOM＋HCG）, and 4700,000 fertilized eggs and 2825,000 fry were obtained in 2009 and 2010. In the study, the techniques of artificial propagation of the skin carp were studied including sexual distinguish, identification of maturity degree, spawning temperature and time, hormone injection, artificial insemination and hatching.

Juvenile lenok Brachymystax lenok were reared in ponds with running water at 2.8-16.8℃.,and had mean body weight of 60.53±27.60g in 12 months, 323.37±74.61g in 24 months, and 735.83±164.80 g in 30 months. The lenok will have marketable body weigh of over 500 g in 24-28 months. The lenok showed better growth in 2-3 years old than in 1 year old. The coefficient varia- tion in body weight wase changed from 20% to 55%.

The types of digestive enzymes were analyzed in digestive tracts of common carp Cyprinus carpio silver carp Hypophthalmichthys rnolitrix, bigheand carp A ristichthys mobilis, grass carp Ctenopharyngodon idellus by polyacrylamide gel electrophoresis, and the relative activities of the digestive enzymes were determined in the fishes by colorimetry and titration.The results showed that the order of the protease activity was arranged as common carp 〉silver carp 〉 bighead carp 〉 grass carp, and that for amylase activity as grass carp 〉 bighead carp 〉common carp 〉silver carp. The digestive enzyme expression in these fishes was found to be paralleled to the histology structure of digestive tracts. The maximal digestive enzymic activity was observed in the 2/5 parts in anterior end of the digestive tract （G1, G2）, where was found to be the main place for digestion in those stomachless fishes, followed by the following 1/5 part of digestive tract （G3）. The minimal digestive enzymic activity was occurred in the last 2/5 parts （G4, G5） of the intestines. The findings provide a theoretical basis for the nutritional physiology, the development of feedstuff and the management for germplasm in these fisheries.

Grass carp Ctenopharyngodon idellus juveniles with body weight of 110±5g reared in a net cage of 1.0m×0.5m×1.0m were fed the basal diets supplemented with different levels ofhypericin （0%, 0.066%, and 0.132%）, chlorogenic acid （0%, 0.04%, and 0.08%） and scleroglucan （0%, 0.2%, and 0.4%） at water temperature of 25±2℃ for 35 days to evaluate the effects of the additives on growth performance and immune ftmction of the grass carp juveniles. The results showed that there were no significant differences in weight gain rate and specific growth rate in the juveniles in all experiments （P〉0.05）.However, the juveniles fed the diet containing 0.08% chlorogenic acid had significantly higher final body weight and hepatosomatic index than the juveniles fed the control diet did （P〈0.05）. All of the additives significantly enhanced the activity of alkaline phosphatase （AKP）, the peak value in the fish fed the diet supplemented with 0.08% chlorogenic acid, and no significant differences in AKP activity among all treatments. There was significantly higher activity of superoxide dismutase （SOD） in 0.132% hypericin group than that in the control, whereas there was no significant difference in SOD between the treatments and the control groups. The grass carp juveniles fed the diet supplemented with 0.2% scleroglucan had significantly higher lysozyme activity. The three additives were not found to affect significantly the content of malondialdehyde （MDA） in the serum.

The relationship between morphometric attributes and body weight ofEsox reichrti Dyhowsk were analyzed on the basis of the measurement of 13 morphometric attributes form 332 E. reichrti in this study. Total length（X1）, standard length（X2）, head length（X3）, snout length（X4）,body width（X5）, head width（X6）, interorbital distance（XT）, body depth（Xs）, head depth（Xg）, caudal peduncle depth（X10）, caudal peduncle length （X11）, oral fissure width （X10）, oral fissure length （Xn）and body weight （Y） were measured. The correlation coefficients and path coefficients were calculated by correlation analysis, path analysis and multiple regression analysis. The results showed that all the correlation coefficients between each independent variable and dependent variable （body weight） were all at significant level （P〈0.05） or extremely significant level （P〈0.01） excepting for the correlation coefficients between head length and body weight of 0^＋ years old. There were some differences on path coefficients of Esox reichrti from different years old. While the pathcoefficients of standard length and head depth to body weight all achieved very significant level （P〈0.01）, among them standard length was the most predominant variable to affect body weight, and it was a key effective factor to body weight. The results of determinant coefficients analysis revealed that the determinant coefficients of standard length gave a predominant determinative effect, whereas the others exhibited a slight direct effect and significant indirect effect on the body weight via standard length. The diversification of determinant coefficients analysis was consistent with that of path analysis. The high value of multiple correlation index R2 〉0.85 between morphometric attributes and body weight suggested that the selected attributes were practical. The morphometric attributes were used to establish the multiple regression equations as LgY = -1.411 ＋ 0.395Lg X8 ＋ 0.576Lg X1 ＋ 0.092Lg X10＋ 0.538Lg X7＋ 0.35Lg X6;LgY = -4.132 ＋ 0.866Lg X1 ＋ 0.102Lg X12 ＋ 0.083Lg X7;LgY -4.186 ＋ 0.772Lg Xj ＋ 0,195Lg X7;LgY = -2.542 ＋ 0.372Lg X1 ＋ 0.185Lg X3 ＋ 0.256Lg X5＋ 0.23Lg X7;LgY =-4.585 ＋ 0.816Lg X1 ＋ 0.178Lg X7 for 0＋ to 4＋years old. This paper provided theoretical evidence and perfect measure target for breeding of E. reichrti in aquaculture.

The body weight, total length, standard length, fork length, body height, body width, head length, head height, head width, eye diameter, interorbital width and snout length were measured in 900 over 1-year old Hucho taimen juveniles from 20 full-sib families. The correlation index （R2）, path coefficients （Pi） and determination coefficients （Di） were calculated based on independent variables of morphometric attributes and dependent variables of body weight by correlation analysis, path analysis and multivariate analysis. There were significant difference in all 11 correlation coefficients between each morphometric attribute and body weight （P 〈 0.05）. Exclusion of standard length, fork length and head length attributes that shared the collinear with total length, the path analysis revealed that the eye diameter and snout length had no significant effect on the body weight. Among the remain six attributes, the total length was found to show the significant effect on the body weight with the direct effect efficiency s of 0.5549. Judging by the results of high determination coefficients （R2=0.9643）, the six attributes were the key effective factors to the body weight. The path formula was expressed based on the independent variables of total length, body height, body width, head height, head width, interorbital width and dependent variables of body weight by using multivariate analysis as log （body weight） =-3.9130＋1.7039 log （total length）＋0.2626 log （body height）＋0.2740 log （body width）＋0.1765 log （head height）＋0.3460 log（head width）＋0.2624 log（interorbital width）. These results provided a theoretical basis with selection of taimen broodstock and measurement of the morphometric attributes in aquaculture.

The enzyme activities of superoxide dismutase （SOD） in blood plasma and liver were analyzed 2 days after Enrofloxacin withdrawal in starlet （Acipenser ruthenus Linnaeus） and Amur sturgeon （Acipenser schrenckii Brandt） orally administrated for En- rofloxacin at a dose of 0, 20, 40, 60, 80 and 100mg/kg fish for 5 days to evaluate changes in SOD activities and mechanism of the drug metabolism in both sturgeon. There was SOD enzyme in both sturgeons at a different level and the SOD activities were found higher in the livers than those in the blood plasma no matter whether the drug was delivered or not. The SOD activities were found to be increased first and then decreased in the two tissues under the different drug delivery concentration, with the maximal value at the concentration of 40 mg/kg fish. In the blood plasma, hardly change in the SOD activities was observed through the period of drug delivery and there were higher SOD activities in the starlet than those in the Amur sturgeon. However, the SOD activities were fluctuated sharply through drug delivery in the liver, in which there significantly higher SOD activities in the Amur sturgeon than those in the starlet at a concentration of less than 40 mg/kg fish. It was the opposite case at a concentration of more than 40 mg/kg fish.

The changes in plankton species community, cells abundance, dominate species and seasonal variation in brood sturgeon culture ponds were studied from May to September in 2009. The results showed that the sediment resuspension caused by brood sturgeon＇s daily movements induced Secchi depth transparency stable at low levels. The Chlorophyta Selenastrum spp. and Chlorella spp. were found to be dominant in phytoplankton community. The abundance of phytoplankton were found to range from 1.0883 × 10^7ind./L to 1.5662x 10^7ind./L, and biomass range from 14.6438 mg/L to 19.2535 mg/L. The Rotifera and Copepoda were dominant in zooplankton community. The abundance of zooplankton was ranged from 162.0000ind./L to 560.0000 ind./L ,and biomass from 0.3795 mg/L to 1.5482 mg/L. The changes in plankton community structure were attributed to the daily movements of the brood sturgeon.

An investigation on the community structure of phytoplankton and environmental impact assessment was carried out in Harbin section of Songhua River in August,2008. The results showed that a total of 72 species 43 genera 7 phylums of phytoplankton were recorded, the community structure of which mainly belongs to Chlorophyta, Bacillariophyta and Cyanophyta. The dominant species are completely from Chlorophyta Cyanophyta and Cyclotella of Bacillariophyta.Based on the dominant species, abundance and biomass, pollution indicator community and physical-chemical indicators, the comprehensive assessment indicates that Harbin section of Songhua River was eutrophication in summer.The construction of Dadingzishan Navigation and Hydropower Project has been leading to raising the water level and reducing the flow rate in Harbin section of Songhua River, resulting the slow succession of phytoplankton community structure from blue and green algae to the diatom in this water in summer.And the water bloom will break out easily.

In situ hybridization molecular hybrid technology as a combination of the basic principle of molecular hybridization and immunohistochemical is provided with a high application value, especially digoxigenin marker, which is characterized by safety, convenient, time-saving, and superior to biotin markers and radioactive marker technology in sensitivity and quality control. In this paper, the basic principles of digoxigenin in situ hybridization was described, and the current applications of this technique in breeding and disease diagnose were discussed in aquatic animals.

In this paper, existing forms of arsenic in the seafood that are connected with food safety and seashells physiology and biochemistry was reviewed. The limit content of arsenic in seawater is no more than 0.03mg/kg based on the standards, while, inorganic arsenic in soft tissue of seashell is between 0.Smg/kg and lmg/kg. At present, two-compartment model was applied to describe the heavy metal harm on shells. The other models was changed or improve from two-compartment model. It is proposed to strengthen the hazards of heavy metals on the description ofAnadara uropygimelana. This work responds to international technical barriers to trade actively, and also expands the area of heavy metals in shellfish.

Salmons and trouts are fishes that are sensitive to the temperature and the environment, the impacts of climate change on salmons and trouts especially the increased temperature arouse the change of environment impact salmons and trouts is obvious.This paper reviews the scientific literatures about the impacts of climate changes on salmons and trouts, reviews the impacts of climate changes on aquatic organisms in terms of habitat environment,then reviews temperature, change in C02 concentration, change in precipitation and acid rainfall, the change in the increased UVB radiation and the disease of salmons and trouts. This paper finds some existed problems such as the research blank,zone limitations,lack of estimate model and give some advices about the future research.

The effects of feeding regimes on growth and immune indices in juvenile sea cucumber（Apostichopus japonicus） with body weight of 0.745±0.3g fed the diet containing selenomethionine（0.5 mg/kg） were studied at water temperature ranging from 9℃ to 13℃ from March 10,2010,to May 9,2010 in a lab.Total of 150 individuals were selected,randomly stocked into tanks of each 50 cm ×40 cm ×30 cm at a rate of 10 individuals per tank,and fed the diet containing seleniomethionine once daily（Group 1）,once every 5 days（Group 2）,once every 10 days（Group 3）,once every 15 day（Group 4） and once daily for the diet without selenium（Group 5,as control group） with triplication for 60 days.The results showed that the sea cucumber fed the diets containing selenium had significantly higher survival than that in the control group（P 0.05）,even though they had no significant differences in the specific growth compared with the animals in the control group（P 0.05）.There were very significantly higher activities of superoxide dismutase（SOD）（78.34 U/ml） and glutathione（GSH）（2.87×10-5mol/L） in the Group 2 than those in the control group（P 0.05）.No significant difference in the concentration of GSH was found between Group 2 and Group 3,and Group 4（P 0.05）.Compared with the other groups,there were higher acid and alkaline phosphatase activities（2.42 U/ml,and 5.76 U/ml） in Group 1,without significant difference（P 0.05）.It is recommended that the sea cucumber be fed the diet containing seleniumomethionine every day for promotion of survival and immunity.

A 21-day feeding experiment was carried out to investigate the effect of water temperature on activities of digestive protease,amylase and lipase in stomach,pyloric caeca,liver,and gut in juvenile lenok Brachymystax lenok with body weight of 11.3±0.94g cultured and fed to satiation twice（08：00,and 15：00）a day）at water temperature of ：6℃,14℃,or 22℃.The results showed that： the minimal protease activity was observed in the stomach at 22℃,significantly lower than that in the other groups（P 0.05）.The maximal activities of lipase were found in the gut and pyloric caeca at 14℃（P 0.05）.There were significantly higher activities of amylase were showed in the gut and pyloric caeca than those in the stomach and liver at 14℃ and 22℃（P 0.05）.The maximal activities of amylase were occurred in all examined digestive organs at14℃,and there were significantly lower amylase activities in the liver and gut at 6℃than that at 14℃（P 0.05）.

The acute toxicity including median lethal concentration（LC50） and the safe concentration of seven kinds of disinfectants to hybrid sturgeon（Acipenser baeri♂ × A.schrenkii ♀） juveniles with body weight of 12.2±0.7 g was studied in a 90 cm×60 cm×30 cm tank at water temperature of 22-24 ℃.The sensitivity rank of the hybrid sturgeon to the drugs was found to be arranged as the following：trichloroisocyanuric acid powder chloramine T povidone lodine solution chlorine dioxide formalin oxytetracycline hydrochloride sodium chloride.The safe concentration was found 0.21 mg/L for trichloroisocyanuric acid powder,2.59 mg/L for chloramine T,3.88 mg/L for povidone lodine solution,6.35 mg/L for chlorine dioxide,9.86 mg/L for formalin,143.45 mg/L for oxytetracycline hydrochloride,and 2396.03 mg/L for sodium chloride.It was found that the povidone lodine solution,chlorine dioxide,formalin and sodium chloride were better choices for hybrid sturgeon＇s disinfection,while trichloroisocyanuric acid powder and oxytetracycline hydrochloride have a special sensitivity to the hybrid sturgeon juveniles,whose disinfection concentration was lower than that in conventional cultured fish.Since the toxicity of chloramine T was found to be closely related with the water pH value,more attention should be paid to the pH value in the water in which the chloramine T is administrated.

The histological and morphological ontogenesis of liver and pancreas in taimen Hucho taimen was studied by serial section technique.The results showed that there are significant differences in the taimen from most of the teleost in that the liver ontogenesis initiated before hatching in the taimen and the pancreas ontogenesis was appeared after hatching.The liver primodium was observed 18 days after fertilization,and the pancreatic cells were found 8 d after hatching,and the liver cells to have fat storing 18 days after hatching,indicating that the liver development is involved in yolk absorption.The liver and pancreas are independent organs,and have prolific tubes.

Influence of salinity on digestive enzyme activity of juvenile jade perch Scortum barcoo was investigated in this study.Variations in specific activities of pepsin,amylase and lipase were studied in the juveniles with body weight of 2.50 ±0.23 g cultured at a salinity of 0,5,8,11,13 and 16 for 20 days at water temperature of 25±2℃.The salinity was showed to have significant effect（P0.05） on the activity of pepsin and to have very significant effect（P0.01） on the activities of amylase and lipase of juvenile jade perch Scortum barcoo.The activity of pepsin was showed to increase with the salinity rising first and then to decrease,the peak at a salinity of 13.The activity of lipase was inhibited by the salinity rising,but increased rapidly at a salinity of 13.The activity of the amylase,however,was found to be significantly decreased as the salinity rising.It can be concluded that the environmental salinity has influence on the digestive enzyme activities of the juveniles significantly,and different digestive enzyme activity will vary with the change in salinity.

Japanese dace（Leuciscus hakonensis）,the only anadromous member in the family of Cyprinidae,is found at the coast of Pacific in Asia.The main ecological characteristics including body length,body weight,age,growth and fecundity,gonado-somatic index,and condition factor in spawning migration period were evaluated by the 890 samples collected in Suifen River in 2009.The broodstock migrating to the upstream were found to spawn in Suifen River three times,from mid-march to the beginning of April,from middle to the end of April,and in May.The spawning fish showed golden in body color in the first spawn,silver in body color in the second spawn,and deep color in the third spawn.There were different sex ratio,gonado-somatic index,and condition factor in spawning population,the second batch being the main predominant reproductive population.Some measurements to protect the proliferation of this fish were proposed based on the main ecological characteristics here.

In this paper,genetic structure of the broodstock of mirror carp（Cyprinus carpio L.） including 208 samples（106 females and 102 males） was analyzed using 26 microsatellite markers.Total 153 alleles ranging from 108 bp to 400 bp in size were screened and several genetic parameters were used to evaluate the parental population.There were 5.8846 alleles on average with the mean effective alleles of 2.8625.The mean observed heterozygosity value was found to be 0.5063 and the mean expected heterozygosity value of 0.5602.The mean value of polymorphism information content was 0.5292 in 26 microsatellite loci.The relatively high level of genetic diversity was statistically found in the breeding population.Although the population accorded with Hardy-Weinberg equilibrium by checking by χ2 test and genetic departure index,severe heterozygote deficit was shown to be derived from artificial selection in many loci.The genetic distance was varied from 0.0256 to 0.9943 among the individuals.A cluster gram was constructed based on UPGMA methods using PHYLIP 3.6 software package.Based on the map,two breeding groups were selected to breed offspring and the fry from the control population was reared from the total broodstock.The selective offspring populations showed relatively high genetic diversity with the average expected heterozygosity ranging from 0.5414 to 0.5449.In Addition,the selective offspring population had good growth,from 14.81% to 63.71% higher than that in the control population.The successive two year growth revealed that the microsatellite markers-assisted population selection could hold genetic diversity and avoid inbreeding.It is superior to construct a good growth population of the mirror carp.

The resources of migratory spawning groups and changes in population structure were surveyed in a total of 9160 statistical samples of chum salmon Oncorhynchus keta collected in Ussuri River from October 4 to October 21 in 2010.The results showed that water temperature and dissolved oxygen have a great impact on the quantity of spawning chum salmon daily.Two peaks were observed with an average of 64 individuals in a daily single boat catch.The individuals with body length of 55~65 cm were found to account for 74% in the group,with very similar ratio of male（36.82%） to female（36.58%） for the individuals with body length of 55~60cm.For the individuals with body length of less than 55 cm,however,the male individuals（27.17%） had higher proportion than the females（12.75%） did.There was higher proportion in the female（48.61%） than in the males（34.25%） in the chum salmon with body length of over 60 cm.The individuals with body weight of 2 000~3 000 g comprised of 57% in the group surveyed,and for the individuals with body weight of over 2.500 g,there was higher proportion in the females（61.73%） than in the males（46.06%）,with the ratio of female to male = 1.09：1.In the group of the chum salmon with body weight of above 2 500 g the females were shown the maximal proportion（36.06%）,followed by in males（28.8%） with body weight of less than 2.500 g.The chum salmon production in this year was the maximum in the past 15 years compared with the past data,indicating that the overall amount of resources presents an increasing trend year by year,but that the fish become smaller in size,with predominant females.

Lake Xingkai（Khanka） and lake Mini-xingkai locate in the northeast boundary of China,are just separated by a natural mound.Large ice fish（Protosalanx hyalocraniu） was introduced into lake Mini-xingkai to increase the fish yield unsuccessfully,however,it developed its population very well after getting into Lake Xiangkai with the flood from lake Mini-xingkai.Fish composition of Lake xingkai and lake Mini-xingkai was investigated from January through December in 2010 to find out the relationship between Large ice fish population development and the differences of fish community.The investigation results in 56 species of fish including 3 new record（i.e.chum salmon Oncorhynchus ketaPike,perch Lucioperca lucioperca and Misgurnus moloity（Dybowski）,Misgurnus moloity（Dybowski））in lake Xingkai,and 33 species of fish including 3 new records（i.e.fat minnow Sarcocheilichthys lacustris,northern sheatfish Silurus soldatovi and Large ice fish）,meaning sharp reduce of 10 species in the past 15 years in lake Mini-xingkai.There is still relatively high similarity in species composition between the two lakes with Sorenson index of 0.72 while the biomass composition was significantly different resulted from the different environmental characteristics.As a large lake located in subfrigid zone,Lake xingkai has its own special hydrological and ecological characteristics,indicated in less biomass of fish that prefer living in macrophyte lakes.The contribution of fish community differences of lake Xingkai from lake Mini-xingkai to Large ice fish population growth was discussed in this paper.

Seasonal changes and horizontal distribution of zooplankton community structure and diversity were investigated in the lower branch of River Wusuli in spring（May）,summer（July） and autumn（October） of 2010.The results showed that the zooplankton population was heavily comprised of Protozoa（abundance of 87.8 %）,and Rotifera（biomass of 68.4 %） in which there were small dominant species in size and higher diversity,supplying abundant natural food resources for many excellent native aquatic animals,especially for Pacific salmon Oncorhynchus keta Walbaum in the lower branch of River Wusuli where was the important reproductive and growth grounds of the excellent native aquatic animals in China.The abundant zooplankton featuring active metabolism,rapid reproduction,and wide distribution had a great role in material circulation and energy flow because it was the important part of aquatic ecological system in River Wusuli.Also,the zooplankton was characterized by sensitive reflection to changes in water quality,and then was widely used in river health assessment.

With the development of molecular biology,the approaches for closely related species and origin identification of aquatic organisms has developed from morphological way to molecular level.The article summarizes current protein and DNA techniques that have been applied in corresponding identification（e.g.,chromatography,immunology identification,and protein electrophoresis,DNA sequence analysis,PCR-RFLP,RAPD,AFLP,SNP,SSR,ISSR,Real-Time PCR,species-specific primer PCR,PCR lab-on-a-chip） and makes comparison of their advantages and disadvantages.On the basis of the advances above,the future development tendency of the approaches is expected in the present article.

Endocrine cell could produced many kinds of gut hormones with the function of regulating stomach and intestine.Besides promoting the digestion and absorption of nutrient substance in stomach and intestine,these hormones could controlled feeding behavior,regulated the movement of digestive tract and trophic action of cell,even influenced the activity of other endocrine glands.Understanding the basic overview of endocrine cell in intestine was conducive to progress the penetrating research on digestive physiology of fishes.Histochemistry immunocytochemistry and electron microscope technique were important ways to study the identification,location and morphology of endocrine cell in digestive tract.Using these techniques could revealed biological function and mechanism of action of endocrine cell in digestive tract,which has meaning to research the physiological mechanism of ingestion,digestion and absorption of fishes.Thus,aimed to offer reference for digestive physiology,endocrinology and nutriology of fishes,we overviewed the progress and main methods in internal and overseas studies of endocrine cell in digestive tract of fishes for the past few years.

Climate warming has been a world-concerned global problem.It brings a series of serious consequences,greatly impacts human survival and development.To reduce carbon dioxide emissions and mitigate global warming,the development of the low carbon economy based on low energy consumption,low pollution and low emission has been our common sense.Fixing and sequestrating greenhouse gases by biological carbon sink is one of the most economical and effective ways.By filtering plankton,filter-feeding fish can reduce indirectly atmospheric carbon dioxide concentration and exert carbon sink function.The paper described carbon cycle of freshwater ecosystem without feeding,and presented carbon sink function of filter-feeding fish.At last,carbon sink amount of filter-feeding fish is evaluated based on 2009 relevant statistics of Chinese aquaculture.The research will make a good preparation for low carbon development of freshwater fisheries,and impel the scientific and healthy development of modern fisheries.

The effects of probiotics I containing primarily Bacillus subtilis and probiotics II containing a mixture of various microorganisms on weight gain,food conversion ratio and drug cost of common carp（Cyprinus carpio）,Crucian carp（Carassius auratus） and grass carp（Ctenophyargodon idellus） in culture ponds in Heilongjiang and Liaoning provinces.The probiotics,alone or together,were showed to have influence on weight gain,the food conversion ratio and the drug cost in the fish culture.There were 423.57% higher weight gain in Heilongjiang province and 90% higher weight gain in Liaoning province in the ponds treated with the probiotics used together,than that in the control ponds with lower drug production cost of 29% in Heilongjiang province and 56.25% in Liaoning province.The food conversion ratio was found to be decreased by 0.35 and 0.05 in the ponds treated with probiotics used together,indicating that the probiotics have important influence on the profit of grass carp culture in Liaoning province and of common carp farming in Heilongjiang and have a promotion of green aquaculture with less drugs,less feed and more profits.