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.