Abstract:This study is based on a survey carried out by the longliner “Shengliancheng 719” in waters near Marshall Islands from Oct,2006 to May,2007.Based on the survey data collected by “Shengliancheng 719” at 43 sampling stations,the vertical profile data of temperature,salinity,dissolved oxygen concentration and the catch rate data of blue shark were applied to develop the “Integrated Habitat Index (IHI)” models by the quantile regression method.Models were developed for six water strata from 40 m to 280 m(40 m each)and the entire water column to understand the blue shark’s spatial distribution.Models were developed with the consideration of interactions among environmental variables. IHI model of the entire water column was developed using the weighted average temperature,salinity,dissolved oxygen concentration and the thermocline parameters,such as,upperlimit depth,lower-limit depth,upper-limit temperature,lower-limit temperature,intensity,thickness,temperature difference.Models of five water strata from 40 m to 240 m and the entire water column were reasonably developed.The measured environmental variables at 43 sampling stations were input into the IHI models to predict the IHI of five strata and the entire water column.The paired two sample t-test was used to calculate the Poisson correlation coefficients between predicted IHI and observed catch per unit effort(CPUE)of five strata and the entire water column.The Poisson correlation coefficients were assumed to indicate the predictive power of the IHI model.The trend line of the arithmetic average about the predicted IHI of five strata was compared with those of the catch rates in the specific depth stratum.The measured environmental variables at the other 18 sampling stations were used to validate the models’ predictive power.These data were input into the CPUE models to predict the CPUE of five strata and the entire water column.A comparison between the predicted and observed catch rates at five strata and the entire water column was conducted by a paired two sample t-test to validate the IHI models.The results showed:(1) the predicted CPUE had greater relevance to the observed CPUE,the models’ predictive power was good;(2) the key environmental parameters in the IHI models differed among the depth strata.This might be resulted from the blue shark’s specific biology characteristic,the different ecological factors,and the different life stages of blue shark;(3) the blue sharks’ IHI s in the areas of 9°N-12°N,172°E-176°E and 3°N-5°N,166°E-169°E were relatively higher;(4) the optimal depth that blue shark inhabit was from 80 m to 120 m in the survey area.The high IHI area in 80-120 m stratum was similar to the high IHI area of the entire water column.It means we could use the IHI distribution in 80-120 m stratum to express the IHI distribution of the entire water column.

Abstract:Concentrations of Zn were measured in oysters collected from 15 stations along Guangdong coastal areas during the period from 1989 to 2010.According to the more recent sampling data and the historical data,the spatialtemporal characters of Zn in oysters were analyzed,and then the pollution level of Zn was evaluated with single factor index and noncarcinogenic hazard index.The results showed the average concentration of Zn in oysters from the study sites was about 211.5 mg/kg with a lognormal distribution.In addition,annual variation of Zn in oysters depicted a threephased trend pattern,the average concentration of Zn in oysters decreased slightly during the period from 1989 to 2007,and then reached a stable concentration of 197.0 mg/kg,and increased obviously during the period from 2007 to 2009,and then presented a gentle decline from 2010.Spatial variation of Zn in oysters showed the pollution level of Zn in oysters from Pearl River Estuary was higher and a different spatial trend of Zn was observed,which was different from the results from East Guangdong coastal waters and west Guangdong coastal waters.Furthermore,the results showed no obvious effect on human health according to the evaluation of single factor index and noncarcinogenic hazard index,which indicated a low pollution level of Zn in oyster,but there is no established standard of Zn level limit in consuming the oysters.

Abstract:The cDNA sequence of CD4 homologue was cloned from the mandarin fish Siniperca chuatsi.It consists of 2 356 bp,encoding 469 amino acids,and this molecule has a typical four Ig-like domains(V1-C1-V2-C2)and shares some fundamental conserved structures,i.e.WTC motif in D2 domain,N-glycosylation site in D4 domian and the CXC motif in the cytoplasmic tail.Unlike avian and mammalian CD4 molecules,the mandarin fish CD4 sequence lacks the Cys pairs in the first Ig-like domain,but has a unique possible disulfide bond in the third domain.These differences suggest that mandarin fish CD4 molecule may have a different structure,which may in turn influence its binding with MHC Ⅱ molecule and probably subsequent T-cell activation.The CD4 was expressed mainly in thymus,and following stimulation with LPS,its significant increase(P<0.05)at mRNA level was observed 8 hours post injection in thymus,spleen and headkidney.The mandarin fish CD4 shared a relatively high level of similarity(57%) with that in sea bass Dicentrarchus labrax,and in the phylogenetic tree,the mandarin CD4 was clustered with that in sea bass.The cloning of CD4 in the mandarin fish may serve as a basis for further functional characterization of fish T lymphocytes.

Abstract:Effects of different temperatures (5-34 ℃),different salinities(10-50),different nutrient concentrations and different nitrogen forms on chlorophyll fluorescence parameters of young seedlings of Sargassum thunbergii were researched in this paper.The main parameters determined in the study included the optimal chlorophyll fluorescence quantum yield(F_v/F_m)and the maximum relative electron transport rate(rETR_max)of photosystem II.The results are shown as follows:(1) If nitrogen concentration or phosphorus concentration was higher than 8 mg/L and 1.2 mg/L respectively,or temperature was greater than 28 ℃,there were significant effects on the photosynthesis of young seedlings of S.thunbergii.(2) Short time treatments in 5-15 ℃ and six hours treatments in 10-50 salinity of seawater did not affect the F_v/F_m of young seedlings of S.thunbergii obviously.(3) If nitrogen concentration and phosphorus concentration was 2-4 mg/L and 0.2-0.8 mg/L respectively,and moreover,NH⁺₄-N∶NO^-₃-N was equal to 1-3,it was beneficial to the photosynthesis of young seedlings of S.thunbergii.

Abstract:In this study,full-length cDNA sequence of heat shock protein 70(HSP70) was isolated from hepatopancreas of Exopalaemon carinicauda,which was named Ec-HSP70.The fulllength cDNA sequence of heat shock protein 70 is 2 250 bp,which contains a 83 bp 5′-UTR(untranslated region),208 bp 3′UTR(untranslated region),and 1 959 bp open reading frame(ORF) that encodes 652 amino acid residues.There are three HSP70 family signatures between 8-15,199-206 and 334-348 amino acids residues of Ec-HSP70,and these sequences are highly conserved in Fenneropenaeus chinensis,Litopenaeus vannamei,Penaeus monodon,Marsupenaeus japonicus,Metapenaeus ensis.The phylogenetic analysis based on amino acid sequence shows that Ec-HSP70 has the highest similarity(99.8%) with HSP70 of L.vannamei and F.chinensis, and has above 90% similarities with other crustacean species,indicating that this protein is one of heat shock protein HSP70 family members.The expression of the gene in hepatopancreas and muscle was analyzed by quantitative Real-time PCR,the result shows that the expression of HSP70 gene was higher in hepatopancreas and muscle after stimulation with the tempreture,pH and NH4Cl.The higher expression time of Ec-HSP70 cDNA in hepatopancreas was earlier than in muscle.HSP70 mRNA expressions were inhibited with longer stress time.Hepatopancreas were more sensitive than muscle to the tempreture,pH and NH4Cl stresses.

Abstract:Algae accumulate heavy metal elements from waters and are used to deal with polluted waters.Gracilaria lemaneiformis has been extensively cultivated as a source of commercial agar and the ecomaterials along the eastern coast of China and Nan′ao county,Guangdong Province.This seaweed has very high productivity and could absorb large quantities of N,P,CO₂,and have excellent effect on decreasing eutrophication.Copper and cadmium are extensively used in industry and agriculture and pollute the marine environment.In order to remove the copper and cadmium in polluted waters,the author investigated the accumulation and elimination for copper and cadmium using cultivated G.lemaneiformis as materials in the low copper and cadmium concentration waters.The accumulation experiment results showed that the copper and cadmium could be accumulated by G.lemaneiformis,the copper and cadmium contents in G.lemaneiformis were obviously positively related with the copper and cadmium concentrations in waters,and with the exposed time of G.lemaneiformis.The copper and cadmium contents in G.lemaneiformis exposed to waters mixed copper with cadmium were higher than that exposed to waters with copper or cadmium alone.The uptake rate constant and elimination rate constant were obtained from twocompartment model by nonlinear curve fitting.The curve fitting results showed that the accumulation capacity for copper by G.lemaneiformis was higher than that for cadmium.And the accumulation capacity for copper and cadmium by G.lemaneiformis decreased when the G.lemaneiformis was exposed to higher copper and cadmium concentration waters.The elimination experiment results showed that the copper and cadmium were accumulated in G.lemaneiformis mainly by way of ion exchange,and some of these copper and cadmium were eliminated by the same way.According to the experiment results,to remove copper and cadmium from polluted waters using G.lemaneiformis as materials is feasible.

Abstract:The changes and functions of mitochondria during the process of fertilization membrane(Fm)formation in Scylla paramamosain were investigated by transmission electron microscope.The results are as follows:Many mitochondria assembled densely at one place in the cortex just before the outburst of the ring-shaped granules.When exocytosis happened,numerous mitochondria scattered rapidly around the cortex where cortical reaction was proceeding.Mitochondria increased dramatically by splitting and budding,meanwhile lots of mitochondria that formed in endoplasm migrated to cortex,as numerous ringshaped granules involving exocytosis needed abundant energy.While Fm was swelling,most of the mitochondria gathered under the new plasm membrane to participate in its restoring and formation.After Fm swelled completely,mitochondria decreased suddenly and disappeared since cortical granules’ exocytosis had ceased.In short,the changes of mitochondria on its numbers,shapes and distribution,reflected the trait on physiological activation and energy supply in different stages of Fm formation.From the angle of the changes and functions of mitochondria,this study illuminated the mechanism of Fm formation on cellular level,and provided a new research field for Fm formation in Crustacea.

Abstract:To evaluate effects of thermal effluent on the planktonic ecosystem,we carried out a mesocosm experiment according to the sea surface temperature gradient,near Guohua Ninghai Power Plant in Xiangshan Bay during October 5th to 11th of 2010,and determine biomass(B),respiration rate(R)and primary productivity(P)of marine planktons and the ratio of total primary production and total respiration(TPP/TR)and turnover rate in the planktonic ecosystem.The results show that:in the range of 25.20-26.40 ℃,effects of 0.25 ℃ warming on the B,R and P of all plankton were not obvious,0.52 ℃ warming can elevate the R,P of microplankton and nanophytoplankton.Effects of 0.52 ℃ warming on the B,R and P of picoplankton were not obvious.The TPP/TR and turnover rate in the planktonic ecosystem were increased 1.2 times and 1.5 times,respectively.A theoretical basis is provided for evaluating effects of thermal effluent on the marine planktonic ecosystem.

Abstract:Vitellin is the most important nutrient and energy source for the development of oocytes as well as developing embryos.The quality and quantity of vitellin in the mature ovary play a vital role in the crustacean reproduction and offspring quality.The swimming crab,Portunus trituberculatus,is a commercially important fisheries resource and mariculture species in East Asian countries.Because of overfishing,destruction of coastal spawning and nursery grounds and marine pollution,the landing of this crab has shown a declined trend in East China Sea since 1990s.The decline in natural stock and increase in market demands have driven substantial aquaculture interests for the crab species.However,the seed production of the crab is dependent on wild-caught broodstock,which could become a constraint to the sustainable development of this crab aquaculture.Our previous studies have shown pond-reared female broodstock have poor ovarian development and worse reproductive performance compared to wild females.Therefore,it is very urgent to understand the mechanism of vitellin synthesis and accumulation for female P.trituberculatus. The present study was conducted to purify vitellin from mature ovary of female P.trituberculatus by gel filtration chromatography,and the elution process was monitored at wavelength of 280 nm and 470 nm,respectively.The number and molecular weight of subunits were identified by sodium dodecyl sulphatePAGE(SDS-PAGE)and marker protein,respectively.Then,the rabbit polyclonal vitellin anti-serum was prepared and purified.Based on the vitellin anti-body,we optimized the reaction parameters of Enzyme-Linked Immunoabsorbent Assay(ELISA),and then the stable and standard ELISA was developed for female P.trituberculatus.The results showed that vitellin was divided into three major polypeptides with molecular weight of 102,75,and 66 ku,respectively by the denatured SDS-PAGE.The Western-blotting confirmed all three major polypeptides had specific reactivity with vitellin anti-body.The higher linear correlationship could be found on the sample direct coating ELISA than the antibody sandwich coating ELISA.Then,the optimal dilution rate of purified vitellin antibody and coating period were shown to be close to 1∶90 000 and 8 hours at 4 ℃,respectively.At 37 ℃,the appropriate reaction duration of the first antibody and the second antibody were 2 hours and 1 hour,respectively,while the best color development solution was around 20 minutes.Furthermore,based on these parameters,the standard linear equation,y=0.000 9x+0.399 1(R²=0.986 1,x and y represent Vn concentration and OD₄₅₀value,respectively),was established for the determination of female P.trituberculatusvitellin concentration with the valid range of 200-900 ng/mL.The susceptibility of this ELISA was around 14.9 ng/mL for Vn contents.Finally,the ELISA was used to determine ovarian Vn contents for the identification of validity of this assay.The results demonstrated the mean coefficients of variation of intraassay and interassay were 3.59% and 3.10%,respectively.In conclusion,the developed ELISA of this study is precise,stable and repeatable.

Abstract:Rotifer species are cosmopolitan and the endemism is very low.They are highly susceptible to physical and chemical changes in their environment due to their small size and permeable integument,and they are known to be an important link between the microbial loop and higher trophic levels,so rotifer is an excellent indicator of the water status of a lake.Yangcheng Lake is one of the most important freshwater lakes in China.The total area of the lake is 119.04 km²,aquatic plants are dense providing a food source for crabs and the lake yields high numbers of the Chinese mitten crab(Eriocheir sinensis).Currently,although the ecological effects of the pen culture on the environment have received extensive attention,expert mainly focus on aquatic plants,physical and chemical factors,environmental effects and benthic animals,but rarely reported on the rotifer community structures.To date,no studies have been done on rotifers in Yangcheng Lake in detail.Thus,the aim of this study was to analyze the spatial and temporal variation of rotifer community structure and species diversity in net-pen closing and lake areas,in order to provide the data and theoretical basis for aquatic ecosystem of Yangcheng Lake,biodiversity conservation and sustainable development of ecological-pen-culture.Rotifer community structure and several feature parameters of water quality were investigated in 3 controlled sites in net-pen closing and lake areas of Yangcheng Lake,during June 2008 to May 2009.The relationship of rotifer community structure and environmental parameters was analyzed,various parameters were used to assess the water quality.The totals of 83 rotifer species were collected,belonging to 30 genera and 12 families.The study showed that the annual average density and biomass of 3 sites in netpen closing were lower than those in lake areas,density exhibited significant positive correlations with temperature.The CCA biplot of samples and environmental variables showed that rotifer assemblages followed a water temperature gradient,suggesting that water temperature was the most important factor in determining seasonality,but the pH was the lowest.Different months were affected by different environmental parameters,there was no differentia in sites except April.The CCA biplot of species and environmental variables shows that the warmstenotherm species like Trichocerca sp.,Anuraeopsis fissa,Hexarthra mira in the downleft quadrant have strong positive correlations; the cold-stenotherm species like Keratella quadrata,Synchaeta sp.in the top-right have strong negative correlations; the eurytherm species like Polyarthra trigla and Keratella cochlearis are in the middle of the biplot,which support these two species are dominant ones in a year.According to the Jaccard similarity index(S_J),the high similarity in dominant species occurred between net-pen closing and adjacent lake areas.Water quality showed that 6 sites were all eutrophication and β-α mesosaprobic,although there was a slight degree in sites C₁ and A₁,no significant differences in 6 sites,which was similar to the results by TSI.

Abstract:In this paper,larvae of crayfish Procambarus clarkii were exposed to different concentrations of M.aeruginosa (1.0×10⁶,5.0×10⁶,1.0×10⁷ and 2.0×10⁷/mL)to investigate their impacts on survival and the hepatopancreas ultrastructure of the crayfish.At the same time,adult crayfish were exposed to the same different concentrations of M.aeruginosa and the total hemocyte counts density(THCs),content of hemocyanin in the serum,superoxide dismutase(SOD),peroxidase(POD),phenoloxidase(PO) and Na⁺/K⁺-ATPase in the gill filament were detected.The result shows that:(1) M.aeruginosa can significantly reduce the survival rate of crayfish larvae.When algae cells reached 1.0×10⁷/mL,the survival rate was significantly lower than that of the control group on the 19^th day(P<0.05).When the experiment finished,the survival rate was 48%.(2) The hepatopancreas of crayfish larvae became darkened and hepatopancreas cells were observed to be damaged under the transmission electron microscopy.(3) When exposed to the highest concentration of M.aeruginosa,crayfish acted a stress reaction:THCs of the adult crayfish increased significantly and stayed at a high level after being exposed for 1 d.There were not significant differences for hemocyanin content at the beginning while significantly decreased on 5 d(P<0.05).The activity of T-SOD in serum was inhibited after 1 d,and was activated to a high level on 5 d.The activity of POD and PO showed fluctuation trend.The activity of Na+/K+-ATPase in gill dropped significantly after 1 d (P<0.01),then increased and stayed at a higher level finally.The result indicated that M.aeruginosa has negative impact on the survival of the juvenile crayfish and affects immunity of the adult crayfish which may cause loss of output of crayfish.

Abstract:Induced rate,growth and gonad were studied in triploid Japanese flounder(Paralichthys olivaceus).The result indicated that triploidy flounder was achieved successfully by cold shocking fertilized eggs at 3 ℃ for 45 minutes duration,3 minutes after fertilization when the temperature of fertilization was 14.8-15.5 ℃.Regular growth measurements were done on the achieved triploid Japanese flounder and the control group 120 days,348 days and 630 days after that.The results revealed that there was no significant difference in growth between diploid flounder and triploid flounder after 120 days.But the weight was significantly different between them after 348 days(P<0.05).And the triploid growth rates(full-length,weight)showed extremely significant difference compared to the diploid controls’(P<0.01).The indexes of the ovaries and the testes in the diploid control were respectively 3.3 and 3.1 times of the indexes of the ovaries and the testes in the triploid Japanese flounder.Furthermore,the gonadosomatic indexes(GSI)of the triploid were significantly higher than the control group’s after 630 days(P<0.001).From these gonadal sections,a lot of normal oocytes could be found in the section of diploid ovary,but the triploid ovary stayed in the stage of oogonium stage.Meanwhile,the number of spermatocyte in triploid testis was significantly less than that of the number of spermatocyte in diploid testis.The study obtained 100% triploid rate with this method.Meanwhile,the triploid gonad was hypogenetic and the growth rate of the triploidy was significantly higher than the control group.Thus,the triploid is suitable for promotion in production.

Abstract:To further study the functional characteristics of Apostichopus japonicus mannanbinding lectin(AJ-MBL)and to improve the natural immunity of A.japonicus, a prokaryotic vector of AJ-MBL gene CDS region was constructed.The fusion protein was expressed and purified in prokaryotic system and its bioactivity was studied.The coding sequence of AJ-MBL was amplified by RT-PCR method.After being identified by the restriction digestion and sequencing,the 498 bp of AJ-MBL gene was inserted into pET28a plasmid to yield an identified recombinant plasmid pET-AJ-MBL,which was used to transform the competent expressive cells of E.coli BL21(DE3).After induction with IPTG,samples analysis results revealed that a fusion protein of approximately 17 ku was yielded,and it occurred in the form of inclusion bodies,and could be purified with Ni²⁺ affinity chromatography.The results showed highly expressed fusion protein was acquired.The purified 17ku AJ-MBL underwent hemagglutination assay to test its bioactivity,the results showed that the minimum hemagglutination concentration was 10 μg/mL.These results indicated that the CDS domain of AJ-MBL had high expressed and the fusion protein(17 ku AJ-MBL)was highly bioactivity.

Abstract:The gel-forming properties of salt soluble protein are one of the most important functional properties in processed surimi products,which could affect the texture,emulsion,water holding capability(WHC),gel strength and sensory characteristics of fish products.However,the gelforming properties of salt soluble protein are affected by a lot of factors including additives.To study the influence of several additives(TGase,sodium alginate,carrageenan,kanjoc gel)on the gel properties of salt-soluble protein from Cynoglossus robutu,the multiple regression models were set up between the WHC,strength of salt-soluble protein gel and content of additives according to the quadratic composite rotational experimental design and response surface method,then the optimal quantities of four additives were determined.When the additive composition was TGase 0.36%,sodium alginate 1.00%,carrageenan 1.00% and kanjoc gel 0.71%,the net structure of gel was dense evenly,and the WHC and strength of salt-soluble protein gel were 60.36% and 55.20 g,respectively.Compared with the control group,the WHC and gel strength of salt- soluble protein from Cynoglossus robutus increased by 36.41% and 351.80%.Appropriate additives combination could significantly improve the WHC and gel strength of salt-soluble protein from Cynoglossus robutus.

Abstract:Aestivation is a kind of dormancy that is probably defined as a survival strategy for dealing with arid conditions,food shortage and high environmental temperature.As an adaptation for life in stressful environments,multiple adjustments occurred in aestivated organism including the regulation of defense system.Antioxidant enzymes are regulated in aestivating animals usually.To evaluate the transcriptional regulations associated with antioxidant defense in sea cucumber during aestivation,gene expression of antioxidant enzymes in respiratory tree was analyzed in this study.Five partial sequences of antioxidant enzyme genes were obtained from Apostichopus japonicus transcriptome database:Cu/Zn-SOD(copperzinc superoxide dismutase),CAT(catalase),PHGPx(Phospholipid hydroperoxide glutathione peroxidas),PRDX5(Peroxiredoxin5)and PRDX6(Peroxiredoxin6).The multiple sequence alignment(MSA)was conducted and special primers were designed for Real-time PCR assay.These genes expressions were normalized by multiple internal control genes of NDUFA13(NADH dehydrogenase［ubiquinone］1 alpha subcomplex subunit 13)and ACTB(beta actin),and their variations during aestivation of A.japonicus were analyzed.Compared with the active sea cucumbers (sampled in May),the antioxidant enzymes got transcriptional change in respiratory tree of aestivated sea cucumbers(sampled in Aug):the expression of Cu/Zn-SOD genes got increase to 1.66 fold(P>0.05);the expression of PRDX5 genes got significant increase to 1.69 fold(P<0.05);the expression of CAT and PHGPx got significant decrease to 0.60 and 0.38 fold respectively (P<0.05);no notable expression variation of PRDX6 was found.It was mainly consistent with the variation of these genes expressions in later phase of thermal induced aestivation of A.japonicus(aestivated sea cucumbers sampled on 40 d):the expressions of Cu/Zn-SOD and PRDX5 genes got significant increase to 1.85 and 1.91 fold respectively(P<0.05);the expressions of CAT and PHGPx genes got significant decrease to 0.60 and 0.34 fold respectively(P<0.05);no notable expression variation of PRDX6 was found.The result indicated that the gene expressions of different antioxidant enzymes were regulated differently during aestivation of sea cucumber.

Abstract:With the increasing production and trade of surimi and surimibased foods,consumers have a higher quality requirement.Traditional analysis methods are timeconsumed,consumed large quantities of chemical reagents.Quality of surimi can be rapidly detected using nearinfrared analysis.Seawater surimi(including Alaska pollock surimi,hairtail surimi,sea bream surimi and mix surimi)and freshwater surimi(including silver carp surimi and grass carp surimi)were used in the study.Chemometric methods,including cluster and linear discriminant analysis(LDA)as well as partial least square(PLS)regression,were used to interpret spectral data.Results indicated that NIR method could successfully classify seawater and freshwater surimi with 100% prediction rate.In addition,the PLS models for water and protein content in surimi had good predictability:the correlation coefficients of the models were 0.98 for water and 0.96 for protein.Results showed that NIRS has great potential to be used in determining surimi quality.And important efforts for the practical application of nearinfrared have been made.In future studies,more representative samples should be added to enhance adaptability of models.

Abstract:The pharmacokinetics of enrofloxacin and its metabolite ciprofloxacin were investigated in the mud crab(Scylla paramamosain)kept at a salinity of 33 after a single oral gavage and intramuscular injection(10 mg/kg).The concentrations of enrofloxacin and ciprofloxacin in the main tissues (hemolymph,muscle and hepatopancreas)were simultaneously detected by HPLC.The parameters in hemolymph and tissues were calculated by non-compartment model based on statistic moment theory.The peak plasma enrofloxacin was fast reached after oral gavage and intramuscular injection.The peak time were 0.5 h and 1 min for oral gavage and intramuscular injection,respectively and the peak concentration of enrofloxacin was 12.90 and 31.86 μg/mL,respectively.Area under the concentrationtime curve (AUC)in hemolymph was 216.1 and 816.8 μg/(mL·h),respectively.Enrofloxacin was widely distributed in mud crab tissues.AUC of muscle and hepatopancreas were 445.9 and 817.6 μg/(g·h),respectively,following oral gavage and AUC of muscle and hepatopancreas were 554.7 and 2 573.7 μg/(g·h),respectively,after intramuscular injection.Compared with other aquatic animals,enrofloxacin was eliminated at a medium level.Half-life of elimination(t_1/2z)and body clearance(CL_z)were 26.45 h and 0.054 L/(h·kg),respectively,for oral gavage,and 57.02 h and 0.012 L/(h·kg),respectively,for intramuscular injection.The AUC ratios of ciprofloxacin and enrofloxacin in mud crab hemolymph,muscle and hepatopancreas were 6.68%,3.60% and 4.78%,respectively,following oral gavage,and the corresponding values were 4.16%,7.24% and 1.48%,respectively,after intramuscular injection.Enrofloxacin in mud crab metabolized less ciprofloxacin and enrofloxacin played a main role in the efficacy in the mud crab.The efficacy of enrofloxacin in mud crab was evaluated with C_max/MIC ratio and AUC_0-24/MIC ratio.Oral gavage of enrofloxacin at a single dosage of 10 mg/kg once every 24 h could yield good therapeutic efficacy on vibrio diseases.

Abstract:According to the samples of neon flying squid (Ommastrephes bartramii)collected by Chinese squid jigging vessels during July to October in 2007 in the traditional fishing ground of northwest Pacific Ocean,the population structure,age and growth of O.bartramii are obtained from the statolith microstructure.The results indicated that the mantel length of female squid ranged from 200 to 395 mm with the age ranging from 123 to 256 d,and the mantel length of male squid is between 200 to 353 mm with age ranging from 127 to 274 d.In July and August the dominant age is from 151 d to 180 d,the ages of 181 to 210 d account for the most in September,and the age class of 211 to 240 d takes up the dominant part in October.The hatching dates of sampled squid were from December 2006 to June 2007,and the peak hatching dates are distributed in the months of January to April.The average absolute growth rates of mantle length reached (1.175±0.127) mm/d and (0.952±0.213) mm/d for female and male squids respectively.The relationships between mantle length and age,between body weight and age were best described by linear and exponential functions respectively.The female and male growth showed significant differences.The results indicated most of the catch in the traditional fishing ground belonged to the winter-spring spawning cohort.The monthly dominant age class changes the same as time going on,which further confirms the daily deposition of growth increments of O.bartramii.It is deduced that the squid spent about 4-6 months on the migration from spawning ground to feeding ground.

Abstract:Based on seven bottom trawl surveys conducted in the central and southern Yellow Sea,which covered the range of 120°-124°E,33°-37.5°N,in seven months from January 2006 to July 2009,total of 3 005 stomach samples of seasnail Liparis tanakae with body length of 18-525 mm were collected.Stomach content analysis,cluster analysis and trophic level were used to study the feeding habits and their ontogenetic variation and monthly variation.The results showed that seasnail is important fish species in food web and plays an important role in the marine ecosystems of the Yellow Sea.Seasnail fed on more than 60 prey species.Crangon affinis was the dominant prey item of seasnail,and Enedrias fangi became the dominant prey item instead of anchovy Engraulis japonicus. The feeding habits of seasnail had significant monthly and ontogenetic variations.Seasnail mainly fed on benthon at less than 50 mm body length; on zooplankton,benthon and demersal shrimps at 51-100 mm body length; When it mainly fed on demersal shrimps at 101-350 mm body length,the frequency of fish in the food increased gradually with increasing fish size,whereas the frequency of demersal shrimps decreased; It mainly fed on demersal shrimps and fish at greater than 350 mm body length.Therefore,there were three shifts in feeding habits in the fish at about 50 mm,100 mm and 350 mm body length,respectively.Seasnail at different body lengths belonged to different functional groups in the Yellow Sea ecosystem.Seasnail with less than 50 mm body length belonged to benthivores functional group,fish with 51-100 mm body length belonged to generalist predators functional group,fish with 101-350 mm body length belonged to shrimp predators functional group,and fish with greater than 350 mm belonged to shrimp/fish predators functional group.The food composition of seasnail varied monthly.Cluster analysis revealed that feeding habits in seven months could be divided into four groups.The body length was the main factors that cause monthly variation in feeding habits of seasnail.Seasnail was one kinds of fish with higher feeding activity in the Yellow Sea,but the feeding activity,as indicated by the percentage of empty stomachs(PES) and mean stomach fullness index(MSFI),varied significantly among different classes of sizes and different months.The PES and MSFI each had highest value at 101-150 mm and 51-100 mm size classes,respectively,then all decreased with increasing fish size.So,seasnail with small size obtained higher feeding activity by higher food consumption,but fish with larger size obtained higher feeding activity by higher feeding opportunity.By integration of the PES and MSFI in each month,seasnail had two feeding peaks in August and January in a year.