Abstract:Based on the trawl survey data of krill (Euphausia superba) fishery from the vessel “FURONGHAI” in 2012/2013 fishing season, the temporal and spatial distribution of krill resources were analyzed with the index of CPUE which was standardized as the yield of 3 n mile drag distance in one hour. The results showed that the monthly average of CPUE was relatively stable from January to June, but declined after July. The mean CPUE on sub-area 48.1 was the highest with (25.12 ± 31.04) t/h, and the lowest mean CPUE was on sub-area 48.3 with (11.49 ± 12.06) t/h. The change of net CPUE was greater in sub-area 48.1 than those in sub-area 48.2 and 48.3. Antarctic krill aggregated mainly in the depth of 0-100 m in sub-area 48.1 with the highest CPUE in 25-50 m layer, but they gathered in sub-area 48.2 mainly in 50-150 m layer with the highest CPUE in 100-150 m layer and in sub-area 48.3 mainly in 100-250 m layer with the highest CPUE in 200-250 m layer. Antarctic krill aggregations were mainly found in the coastal areas less than 500 m in depth which were formed as commercial fishing grounds, and the highest population density was in shallow water of 250 m with the CPUE of (17.54 ± 35.26) t/h. The average CPUE was lightly changed between 12–14 t/h in the grounds of 250–1500 m in depth, and the average CPUE was decreased to (9.62±9.54) t/h while the grounds was more than 1500 m in depth. The ground SST was mainly between –1–2℃, and the average CPUE was higher when the SST was in the range of –1–0℃. There were 5 major aggregations found in this survey, which could last more than 2 months with various densities over time. These results provide the basic data for searching Antarctic krill fishing ground and fisheries management, and provide some reference for commercial fishing as well.

Abstract:According to the fishery data of light purse seine fisheries of China, Japan and South Korea and the associated economic data during 2000 to 2011, the Bayesian method was used to construct the bio-economic models of Chub mackerel (Scomber japonicus) in the East China Sea and the Yellow Sea under three assumptions (uniform distribution, normal distribution and log-normal distribution). The resource status and economic benefits under three different management strategies (short-term, medium-term and long-term) were compared and the suitable management strategies were evaluated. The results showed that the most estimated expectation (except for BMSY under the normal distribution scenario) of management reference points under the normal distribution and log-normal distribution was less than that under the uniform distribution. It suggested that from the biological perspective, if the harvest rate is settled to more than 0.4, the biomass after 2031 may collapse, and the more conservative management strategy should be settled the harvest rate at 0.3. The probability of B2031>BMSY is greater than 0.85, and MSY is about 350 thousand tons. Likewise, if only from the economics perspective, the harvest rate is controlled at 0.1, the probability of B2031>BMEY is 1, and the probability of B2031

Abstract:Mandarin fish (Siniperca chuatsi) is a rare and precious economic species of freshwater fish with a long standing reputation because of its fast growth, meat delicate, delicious and nutrient rich. The mature artificial propagation technology has created good conditions for Siniperca chuatsi large- scale cultivation since 1980 s. However, the wild Siniperca chuatsi population is declining due to over exploitation and environmental pollution in their habitat, which may cause the decline of genetic diversity. Mandarin fish is one of abundant species in Poyang Lake and plays an important role in the lake ecosystem. Based on Poyang Lake fishery resources investigation data, we assessed biological parameters and stock biomass of Siniperca chuatsi using FiSAT II software. The results indicated that the length of Siniperca chuatsi population ranged from 77 to 526 mm, and that the relationship between body length (mm) and body weight (g) can be expressed as W = 1.888´10-5L3.042(R2=0.951, n = 577). The estimated parameter for von Bertalanffy growth equation was L∞= 551.25 mm, K= 0.210, and t0 = -0.601. Total mortality (Z) was 1.06 a-1; natural mortality was (M) 0.44 a-1; fishing mortality (F) was 0.62 a-1; the optimum catchable size was 150 cm. The exploitation rate was 0.58, which is in the situation of over exploitation. The initial stock of Siniperca chuatsi in the Poyang Lake was up to 1.92´104 tons, and the Maximum sustainable yield (MSY) was 4384.93 tons. The recruitment and young surplus populations of the spawning stock increased significantly in the reproductive population. Low-age and miniaturization tendency was obvious; however, the growth potential was still high based on the growth equation. The results suggest that active strategies such as reducing fishing intensity of the reproductive population and protecting the spawning grounds are imperative to maintain this precious fishery resources.

Abstract:Fleshy prawn Fenneropenaeus chinensis is one of the most important species for stock enhancement in the Laoshan Bay. To evaluate the potential effectiveness of releasing fleshy prawn stock enhancement, we analyzed the survival rate, growth rate, migratory pattern, and recapture rate of the released fleshy prawn using the Bhattacharya method based on the monitoring survey monitoring survey monitoring surveymonitoring and recapture survey of fleshy prawn from July to September 2012 in the Laoshan Bay. We found that the released prawn mainly inhabited in inner or middle part of the Laoshan Bay, in which the sediments were sandy or sand-mud substratum. In mid-August, the mean body length of the first and second batch released fleshy prawn were 144.9 mm and 130.5 mm, respectively. The ratios of the released and wild fleshy prawns to the total population were 92% and 8%, respectively. The fleshy prawn moved from shallow water to deep water when the water temperature decreased. During the study period (from late August to early October), a total of 0.996 million released prawns were collected with the 0.58% mean recapture rate of fleshy prawn in the Laoshan Bay, which might be explained by the food competition, enemy creature and habitat destruction. Although the recapture rate of fleshy prawn was low, the ecological, economic and social benefits were still gained from the stock enhancement of fleshy prawn in the Laoshan Bay.

Abstract:To investigate the seasonal and spatial distribution of phytoplankton in terms of Chlorophyll a (Chl a) in the scallop Patinopecten yessoensis aquaculture area of Zhangzidao island, northern China, four filed investigations were conducted in June 2011, October 2011, December 2011 and April 2012. Chl a was further divided into pico-phytoplankton (< 2 μm), nano-phytoplankton (2-20 μm) and micro-phytoplankton (>20 μm) size fractions. Results showed that the concentration of Chl a in the surface and bottom seawater of Zhangzidao area ranged from 0.07-6.28 µg/L and 0.16-5.28 µg/L, respectively, and the related average was (1.60±1.38) and (1.31±1.10) µg/L. There were significant differences in the concentration of Chl a among different seasons (P<0.05). The differences of Chl a’s concentration between surface and bottom seawater were highly significant during autumn and spring (P<0.01). Nano-phytoplankton was the most important size-fraction regardless of surface and bottom seawater and accounted for 50.85% and 44.64% of the total phytoplankton, respectively. CCA analysis of the main environmental factors showed that NO3-, PO43- and NH4+ contributed greatly to nano-phytop­lankton while seawater temperature and NO2- gave a great contribution to pico-phytoplankton. The annual photosynthetically produced particulate organic carbon (PPOC) in this area ranged from 40.31 to 1017.64 mg C/(m2·d) with an average value of (386.07±281.80) mg C/(m2·d). More than 38.3% of the fixed carbons by the photosynthesis were taken by the classical food web via the microbial food loop. These results highlight the important role of the microbial loop in aquaculture system of Zhangzidao coastal area.

Abstract:The current study analyzed the distributional and variational feature of nutrients of seawater in the southern offshore area of Huangdao District based on the environmental data collected by surveys from 2008 to 2013. The methods of Eutrophication Index (E) and Organic Pollution Comprehensive Index (A) were used to assess nutritional status and organic pollution condition of seawater. Based on the surveys from 2012 to 2013, the concentrations of dissolved inorganic nitrogen(DIN), dissolved inorganic phosphate(DIP) and chemical oxygen demand (COD) varied within 20.82-197.62 µg/L, 4.52- 52.91 µg/L and 0.39-1.25 mg/L, respectively. Except one station that the concentration of DIP was above the standard limit, all other concentration including DIP, DIN and COD met the second class of national standard. In three seasons, the highest concentration of DIN (86.42 µg/L) was in the spring, and the lowest (38.59 µg/L) was in the summer. The highest concentration of DIP (18.68 µg/L) was in the autumn, and the lowest (9.10 µg/L) was in the summer. The highest concentrations of COD (0.962 mg/L) was in the summer, and the lowest (0.682 mg/L) was in the spring. The concentrations of DIN and COD was gradually decreased from 2008 to 2011 and then was increased in 2012. The concentration of DIP was gradually decreased from 2008 to 2010 and then was gradually increased from 2010 to 2012. The seawater of the surveyed area was at oligotrophic level, showing the low possibility of red tide occurrence. The water quality in the surveyed area was good, indicating that seawater was not polluted by organic matters.

Abstract:To explore the role of insulin-like factor Ⅱ(IGF-Ⅱ) in growth regulation of Cynoglossus semilaevis Günther, the IGF-Ⅱ gene was expressed in vitro and the bioactivity was determined by methyl thiazolyl tetrazolium (MTT method). The mature peptide domain of IGF-Ⅱ gene of C. semilaevis Günther was cloned by PCR amplification and sequenced for verification. The obtained mature peptide fragment was then subcloned into the prokaryotic expression vector pET-28a (IGF-Ⅱ/pET28a). The recombinant plasmid was expressed in E.coli BL21 (DE3) cells and the recombinant IGF-Ⅱ protein containing 6×His tag at N-terminus was induced by IPTG. SDS-PAGE analysis indicated that the obtained IGF-Ⅱ protein was found in the form of inclusion bodies with molecular weight of 11.4 kDa, which accounted for 43.7% of the whole bacterial protein post 2-hour induction with IPTG. Western blotting analysis indicated that the recombinant IGF-Ⅱ protein had the antigenicity to 6×His antibody. The inclusion bodies containing recombinant protein were denaturalized, purified and annealed. The recombinant IGF-Ⅱ protein significantly promoted the proliferation of human breast cancer cells MDA231. Results could provide basic information on the role of IGF-Ⅱ in fish and be helpful to better understand the endocrine mechanism of sex-based dimorphic growth performance of C. semilaevis Günther.

Abstract:The current study investigated the embryonic and early larval development of Rhinogobio ventralis using the micro electronic imaging technology. The running-water hatching way was used to incubate the fertilized egg. The hatching water temperature was 17.6-18.3℃ and DO was 7-9 mg/L. The results showed that the range of R.ventralis egg diameter，egg membrane diameter and egg weight was 1.7-1.9 mm, 6.6-7.0 mm and 0.0059-0.0077 g, respectively, and that the life and swirling movement time of sperm were 96.56-119.12 s and 25.43-31.43 s, respectively. The time period for embryonic development was 56 h at 17.6-18.3℃. Eight embryo development stages of R.ventralis were described, which included fertilized egg, blastoderm, cleavage, blastula, gastrula, neurula, organogenesis, and hatching period. The yolk-sac of larvae disappeared after being reared for 5 days in the water at 18.5-22℃. The yolk-sac of 6-days age larvae disappeared completely, and the late larval stage began. The fin of 30-days age larva was basically formed and scales began to form. The growing larvae further developed into juvenile stage after 30 days. Our study provides theoretical basis and scientific reference for the mass reproduction of R.ventralis.

Abstract:To study the mackerel tuna (Euthynnus affinis) feeding habits and its ontogenetic diet shifts, 435 mackerel tuna were collected for an annual research from September 2008 to September 2009 in the main fishing ports such as Beihai, Basuo, Sanya and Jianghong of the Beibu Gulf, South China Sea. Results showed that the mackerel tuna of the Beibu Gulf was omnivorous and it predated not only the small pelagic fish but also the benthic fish, crustaceans and cephalopods. Pisces were dominant in the diets with the percentage of Index of Relative Importance (IRI%) of 98.57%. Among these, 21 species were identified. As indicated with IRI%, Bregmaceros rarisquamosus (45.50%), Stolephorus zollingeri (11.81%), Theyssa setirostris (5.89%), and Sardinella aurita (5.87%) were principal in the food cons­ituent. The main species changed monthly and it was Sardinella aurita in January; Bregmaceros rarisquamosus in February, March, November, December; Unidentified Pisces from April to July; Sardinella aurita in August; Leignathus riviulatus in September; Stolephorus zollingeri in October. The prey weight and numbers increased when body size of mackerel tuna was less than 340 mm (SL<340 mm), but there were decreased when body size of mackerel tuna was from 341 to 520 (341-520 mm). The spawning periods of the mackerel tuna were spring and summer, mainly from April to August. There were two spawn peaks, June and August, which were recognized by the female gonad somatic index (GSI) that maintained strong feeding intensity during the reproduction periods. Moreover, the peak periods were consistent with the water temperature of pelagic layers provided by France CATSAT fisheries remote sensing system.

Abstract:Turbot (Scophthatmus maximus) breeding, especially the larval breeding, has been seriously affected by the bacterial diseases that were caused by the interactions of fish, pathogens and the environment. The gastrointestinal flora is the dominant location for the occurrence of diseases. This study is to analyze the gastrointestinal microflora of turbot larvae and expound their formation and succession. Using conventional bacteriological culture techniques, we isolated and quantified the bacteria from the gastrointestinal tract of turbot larvae, tank inlet water and feed in a turbot breeding farm. The dominant strains were identified by sequencing their 16S rDNA for alignment with NCBI 16S rDNA sequences database. The results showed that the total bacteria count in turbot larvae GI tract was increased and then decreased from Day 5 to Day 36. From Day 17 to Day 26, the culturable bacteria in GI tract were approximately 105−106 CFU/g, which showed extremely significant difference compared to the other stages (P<0.01). Similarly, vibrio counts were increased initially and then tended toward stable. Day 17 is the cutoff for the significant differences (P<0.05). Ultimately, the numbers of total bacteria and vibrio remained stable at 104 CFU/g in GI tract. Naturally, Vibrios were the dominant strains in the GI tract of turbot larvae. These results indicated that the dominant bacterial strains in the GI tract changed significantly at different developmental stages of turbot larvae. The bacteria in biological feeding could obviously impact the microflora formation in GI tract in the early stage of turbot, and that Vibrio ichthyoenteri was the dominant strain in the GI tract.

Abstract:Tilapia is a very important freshwater aquacultural species in China; however, bacterial disease caused huge economic losses in recent years with the continous expansion of tilapia aquaculture. The aim of this research was to isolate, identify, and test drug sensitivity of bacteria pathogen found in diseased Tilapia nilotica. Six bacteria were isolated from diseased T. nilotica as suspected pathogenic bacteria. The bacteria (NL05) isolated from intestine of diseased T. nilotica was determined as pathogenic bacteria by infection experiment. The LD50 was 1×103 CFU/g. Bacteria NL05 was identified as Aeromonas jandaei. Morphology observation indicated that NL05 was gram-negative, rod-shaped. Thirteen physiological and biochemical indexes were positive including maltose, mannitol, glucose, salicin, and hydrogen sulfide. Ten indexes were negative including saccharum, arabinose, xylose, inositol, and dulcitol. There was 1442 bp in the sequence of 16S rRNA, which was submitted into GenBank (Accession number: KC916744). The phylogenetic tree based on 16S rRNA showed that NL05 was A. jandaei. Drug sensitivity test indicated that NL05 was sensitive to 13 antibiotics including ofloxacin, ciprofloxacin, amikacin, polymyxin B, norfloxacin, rifampicin, and lincomycin, and intermediate sensitive to 5 antibiotics including azithromycin, ceftriaxone, kanamycin, streptomycin and minocycline, and resistant to 13 antibiotics including ampicillin, amoxicillin, enrofloxacin, sulfamethoxazole, and trimethoprim. The results will provide references for the prevention and treatment of diseases caused by T. nilotica.

Abstract:In order to understand the change in the expression of genes associated with the oxidation and the signaling pathway, we infected the shrimp with the white spot syndrome virus, then we used quantitative real-time PCR to analyze the mRNA expression of thioredoxin (TRx), Litopenaeus vannamei p38 (LvP38), catalase (CAT), and peroxidase (POD) genes in the lymph nodes and gill of the shrimp at different time points after the infection (0, 6, 12, 24, 48 and 72 h). The shrimps were divided into two groups (the WSSV-injected group and the PBS-injected group), and we collected 3 shrimps from each group at 0, 6, 12, 24, 48, and 72 h after the injection, and isolated individual samples of the lymph nodes and gills. After the extraction of the total RNA, we synthesized and quantified the first-strand cDNAs with a kit and NanoDrop 3000 respectively, and performed quantitative real-time PCR using Rotor Gene 3000. The results showed that in the WSSV-injected group, the expression levels of TRx, LvP38, CAT, and POD in lymph nodes reached the maximum at 72 h post infection, and there was no significant difference between the WSSV-injected group and the PBS-injected group during the period of 6−48 h. The expression level in the gill of the WSSV-injected group was the highest at 12 h post infection, and then decreased over time. Significant differences in TRx mRNA expression were observed at 48 h and 72 h, and there was a significant difference in CAT mRNA expression at 48 h between the WSSV-injected group and the PBS-injected group. Our data indicated that TRx, LvP38, CAT, and POD might be correlated with the WSSV infection.

Abstract:he amphipod crustacean Eogammarus possjeticus is an ideal live feed for fish and shrimp. However, little is known about the optimal aquaculture conditions for this species. Here we investigated the effects of temperature on the feeding rate and digestive enzymes activities of E. possjeticus using physiological ecology method and enzymatic analysis. Our results demonstrated that there were significant differences in digestive enzymes activities between groups treated at different temperatures (P<0.01). In the range of 15−25℃ the activities of pepsin, trypsin and amylase in E. possjeticus were elevated along with the increase of temperature, especially higher above 20℃. Thus, the optimal temperature for digestive enzymes activities should be 20−25℃. The amylase/trypsin (A/T) value was used to evaluate the feeding habits of crustacean. The A/T values were between 1.2 and 1.5 with small fluctuation, which indicated that the larvae of E. possjeticus had preference to plant diets. The feeding rate of E. possjeticus juveniles was largely affected by temperature (P<0.05), and the predicted maximal feeding rate was 89.84% according to the correlation equation (y= −0.754x2+33.297x−277.57, R2 =0.958) between 20℃ and 25℃. The predicted maximal feeding rate of adults was 32.47% according to the correlation equation (y=−0.247x2+10.463x–78.287 (R2=0.998) at around 20℃. The assimilation rates were similar between the juveniles and the adults of E. possjeticus. The maximal assimilation efficiency was 59.86% for juveniles, and 56.86% for adults, and the corresponding optimal temperatures were 21.30℃ and 21.24℃ respectively. These data suggested that 20−25℃ could be an appropriate temperature range for the cultivation of E. possjeticus.

Abstract:The current study was to develop a PCR-based method to detect Enterobacter cloacae and Enterobacter aerogenes in Macrobrachium rosenbergii. Two pairs of primers targeted sequences located within the omp A gene of E. cloacae and gyr B gene of E. aerogenes were used to detect E. cloacae and E. aerogenes. Samples collected from infected larvae were detected with the developed PCR method. The expected DNA fragments of 385 bp and 201 bp were from E. cloacae and E. aerogenes, respectively, and no PCR products were amplified from other bacterium. The sensitivity test showed that the detection limits of PCR were 103 CFU/ml for E. cloacae and 102 CFU/ml for E. aerogenes. In addition, the detection results of larval samples were consistent with the actual case of the infectious disease. In summary, the PCR diagnostic method was specific and sensitive and is a reliable tool for identification of E. cloacae and E. aerogenes in infected samples with a little time and cost, which would play an important role in quick diagnose, epidemiology investigation and SPF populations construction of the giant freshwater prawn.

Abstract:Cannibalism is one characteristic of Marsupenaeus japonicas with little understanding, which affects the survival rate and the production of M. japonicas. The current study was designed to investigate the effects of the stocking density, food types and abundance on the agonistic behavior of M. japonicas. Three stocking densities (10, 25 and 50 ind/m2) and three food amounts (full food, less food, and no food) were designed. Agonistic behavior were observed and recorded one hour before feeding, during feeding and 1 hour after feeding. The results showed that the agonistic behavior increased with the increasing stocking density. There were significant differences between “before feeding”, “during feeding” and “after feeding” (P<0.05). Feeding time significantly improved the agonistic behavior. Food types and abundance significantly affected the agonistic behavior(P<0.05). Clam meat had better improvement in agonistic behavior than artificial feed. The stocking density did not impact the agonistic behavior before feeding and during feeding, but it had significant effect after feeding(P<0.05). These results revealed that stocking density, food type and abundance could impact the agonistic behavior of M. japonicus.

Abstract:The sea cucumber Apostichopus japonicus is a major aquaculture species in China. The fast development of sea cucumber culture in China has generated some problems such as genetic degradation, frequent diseases outbreak and natural resource depletion, which have impacted the sustainable develop­ment of agro industry of sea cucumber. Heterosis resulting from crosses between different populations is an important component of breed improvement in marine animals. The objective of this study is to determine if heterosis exists between China and Korea populations of A. japonicus. The first generation of four combinations, C(♀)×C(♂), K(♀)×K(♂), K(♀)×C(♂), and C(♀)×K(♂), were obtained from mating and crossing within and between Chinese population (C) and Korean population (K) of A. japonicas. The fertilization rate, hatch rate, settlement rate, growth, disease resistance and heterosis at larval and juvenile stages were compared among four combinations in this study. The results indicated that fertilization and hatch rates were not significantly different between the hybridization groups and self-fertilized groups. The settlement rates of hybridization groups were significantly higher than those of self-fertilized groups (P<0.05). The body length of C(♀)×K(♂) group at juvenile stages was longer than other three groups, showing marked heterosis 9.43%–23.75%. Compared with other three groups, heterosis on body weight of C(♀)×K(♂) group ranged from 4.09% to 34.96% since 150 days after fertilization. In contrast, the K(♀)×C(♂) group did not show positive heterosis except at Day 150. The K(♀)×C(♂) group showed the best resistance against V. splendidus, and the heterosis reached 26.21%. These results indicated that the crosses between different populations might be effective for genetic improvement in A. japonicus.

Abstract:The current study investigated the effects of temperature (7, 12, 17, 22, and 27℃) and salinity (23, 26, 29, 32, 35, and 38) on oxygen consumption rate (OCR) and ammonia-N excretion rate (AER) of small group (S) (1.68-3.48 g) and large group (L) (15.78-20.79 g) red Apostichopus japonicus. The results showed that temperature had significant effect on OCR and AER of red A. japonicus, and that body size significantly affected the AER but not OCR. There was significant interaction between body size and temperature (P<0.01). OCR and AER of S group was increased with the increasing of temperature; however, OCR and AER of L group were enhanced when temperature ranged from 7 to 17℃, and diminished at 22℃, and then increased at 27℃. Salinity and body size had significant effect on OCR and AER (P<0.05), and there was no significant interaction between body size and salinity (P<0.01). The effects of salinity on OCR and AER of two body groups of red A.japonicus showed a shape of ‘M’, which was lower at salinity of 29 and 32 and higher at salinity of 26 and 35. There is a negative regressive function R = aWb between the OCR/AER and body size. O:N ratios in different temperatures were covered range of 4.75-11.74 for S group and 10.71-15.52 for L group, respectively; O:N ratios in different salinities were covered range of 6.37-12.29 for S group and 8.24-12.10 for L group, respectively. These results demonstrated that the large group red type A. japonicus could not tolerate higher temperature and two group sea cucumbers were sensitive to lower and higher salinity. The study indicated that the optimum salinity range for red type A. japonicus was 29-32.

Abstract:To investigate whether Myriophyllum spicatum can substitute Sargassum thunbergii in sea cucumber culture industry, five diets containing 0(A0), 15%(A1), 30%(A2), 45%(A3) and 60% (A4) Myriophyllum spicatum meal were formulated to identify the effect of substituting M. spicatum L. in growth performance, body composition and digestive enzymes activities. The results showed that the growth rate (GR) of sea cucumbers in group A4 was significantly higher than other groups, and that sea cucumbers in group A4 showed the best survival rate (SR) (97.78%). Significantly higher crude protein content was observed in group A4 (50.92%) compared with other groups (P<0.05). The amylase activity of group A3 (0.83 U/g prot) was significantly higher than other groups (P<0.05). The protease activity in group A4 (1.62 U/g prot) was significantly higher than all other groups (P<0.05). The results of this study provide strong evidence to replace S. thunbergii with M. spicatum L. in the sea cucumber culture industry.

Abstract:In recent years, with the rigorous limits on drug residues in the loach Misgurnus anguillicaudatus from importing countries, the M. anguillicaudatus exporting enterprises and the export inspections are facing enormous challenges in drug use and control. The current study investigated the residues and elimination of enrofloxacin (ENR) and ciprofloxacin (CIP) in M. anguillicaudatus to provide a reasonable dosing plan and withdrawal period for the aquaculture industry. The loach M. anguillicaudatus purchased from an aquaculture farm were fed 7 days to adapt the experimental water quality and then divided into three groups at different temperatures, and fed with enrofloxacin or ciprofloxacin at a dosage of 20 mg/kg per day for 7 consecutive days. Samples were collected at various time points to measure the contents of ENR and CIP by the high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). The results showed that both the elimination of ENR and CIP were complied with the first-order kinetics, and the water temperature significantly affected the elimination rate of both drugs. At 25℃, 20℃ and 15℃, it took 25, 32 and 50 days, respectively, for the enrofloxacin compound metabolized to less than 10.0 μg/kg in the body of M. anguillicaudatus. It took 27, 31 and 33 days for ciprofloxacin to metabolize to less than 10.0 μg/kg. Based on the South Korea limits of no more than 10 μg/kg for quinolones in M. anguillicaudatus, a withdrawal period of 32 days is recommended for the M. anguillicaudatus exporters by considering the actual culturing environments in Xuzhou and nearby area.

Abstract:To measure herbicides residues in fishery water, gas chromatography-mass spectrometry was developed to determine trifluralin, pendimethalin, alachlor, acetochlor, butachlor, simazine, atrazine, and prometryn. The samples were adjusted to salinity 20−30 with NaCl, extracted by dichloromethane, and cleaned up with Florisil solid phase extraction (SPE) column. The analytes were detected by gas chromatography-mass spectrometry under the selected reaction monitoring mode and quantified by external standard method. The peak area was linear to the concentration of eight herbicides residues (0.010−1.000 µg/L), and the correlation coefficients (R2) were all more than 0.990. According to S/N≥3, the detection limit of rifluralin, simazine, atrazine, acetochlor, alachlor, prometryn, pendimethalin, and butachlo were 0.022, 0.031, 0.028, 0.038, 0.041, 0.035, 0.025, and 0.020 μg/L, respectivly. The limit of quantification was 0.05 μg/L for all eight herbicides based on the actual samples spiked recoveries between 70% and 120%, S/N≥10, and the relative standard deviation≤15%. The average recovery of the eight herbicides fortified in different negative samples at 0.05, 0.5, and 2.0 µg/L were in the range of 74.7%−97.7%, and the relative standard deviations were less than 12.00%. These results indicated that the method has the advantage of simplicity, sensitivity and repeatability, which could provide technical support for the detection of these eight herbicides residues in fishery water.

Abstract:According to the results of the Phthalic Acid Esters (PAEs) content in the aquatic products collected from Minnan region (Xiamen, Zhangzhou, and Quanzhou) in January and July of 2013, we discussed the PAEs residue levels and the distribution characteristics in different aquatic products and evaluated the contamination status and the ecological risk caused by PAEs. The results showed that the content of PAEs in seawater fish varied from 2.45×102 to 1.13×103 µg/kg (wet weight, similarly hereinafter) and the mean value was 6.78×102 µg/kg. The PAEs content in freshwater fish varied from 4.36×102 to 1.37×103 µg/kg with the mean value of 8.73×102 µg/kg. The PAEs content in shrimp varied from 3.22×102 to 1.27×103 µg/kg and the mean value was 7.76×102 µg/kg. The PAEs content in crab varied from 6.17×102 to 1.20×103 µg/kg with the mean value of 7.91×102 µg/kg. The PAEs content in shellfish varied from 9.77×102 to 1.35×103 µg/kg and the mean value was 1.22×103 µg/kg. Butyl benzyl phthalate (BBP) and di-n-octyl phthalate (DNOP) were not detected in all aquatic products. The order of other four PAEs residues content was di(2-ethylhexyl) phthalate (DEHP) > di-n-butyl ortho-phthalate (DBP) > diethyl phthalate (DEP) > dimethyl phthalate (DMP). PAEs had different levels of residues in aquatic products, suggesting a common phenomenon for the enrichment of PAEs in the aquatic products. Compared with other domestic regions, the detection rate and the value of DEHP were higher, indicating that part of the ecological environment in Minnan region had been polluted by DEHP. The expose risk index (ERI) of DBP and DEHP in organic pollutants through feeding was less than 1, suggesting that the risk of exposure to the PAEs was low and acceptable by consuming the aquatic products.

Abstract:Entenmorpha sp. is widely distributed along the coast of China, particularly in the eastern regions, but it has not been utilized fully. To investigate the adsorption of glucose, cholesterol and nitrite to the dietary fiber extracted from Entenmorpha sp. by the method of complex enzymes (protease and cellulase), different ratios of protease to cellulase (5:1, 10:1, 15:1, 20:1, and 25:1) were used to extract dietary fiber from Entenmorpha sp. The results showed that the ratio of protease to cellulase in the complex enzymes had obvious effects on the adsorption capabilities of the dietary fiber. With the increased protease in the complex enzymes, the adsorption of glucose and cholesterol to the dietary fiber increased and then decreased. The dietary fiber using the 10:1 ratio of protease and cellulase had highest adsorption of glucose (20.03 mg/g). The dietary fiber using the 15:1 ratio of protease to cellulose had the highest adsorption of cholesterol (21.93 mg/g). With the increased protease, the adsorption of nitrite to the dietary fiber increased. The dietary fiber had highest adsorption of nitrite (29.25 µmol/g) at the 25:1 ratio of protease to cellulose. Furthermore, the adsorption capabilities of the diary fiber in the simulated gastric fluid at pH 2.0 and the intestinal fluid at pH 7.0 were investigated. The adsorption of cholesterol to the dietary fiber was higher in the simulated intestinal fluid than that in the simulated gastric fluid, while nitrite was the opposite. The adsorption of glucose to the dietary fiber had no significant difference in the simulated intestinal and the simulated gastric fluids. These results indicated that the adsorption of nitrite to dietary fiber happened in the stomach and cholesterol happened in the intestinal, and that the adsorption of glucose to the dietary fiber happened both in the stomach and in the intestinal.

Abstract:In this study, we analyzed the qualities of fish sauce, fish soy sauce and light soy sauce using the electronic nose. An electronic nose captured the flavors of light soy sauce, fish sauce and fish soy sauce, and the information was assessed with principal component analysis (PCA), linear discriminant analysis (LDA) and loadings analysis. The qualities of the sauces were then determined with the results above together with factors such as amino acid nitrogen, total nitrogen, salinity and the content of free amino acids. The results showed that fish sauce and light soy sauce were first-class products, and that fish soy sauce was a super product. There were a variety of free amino acids in the three sauces. The contents of threonine, glycine, alanine, methionine and lysine in fish sauce were higher than those in fish soy sauce and light soy sauce. The content of flavor amino acids in light soy sauce and fish soy sauce was significantly higher than that in fish sauce. This was because sodium glutamate was added into fish soy sauce and light soy sauce, but there was no added substance in fish sauce. However, the content of essential amino acids in light soy sauce was the lowest. The flavors in the light soy sauce, fish sauce and fish soy sauce were complex. The electronic nose responded differently to the three kinds of sauce, and the ten sensors of the electronic nose could distinguish the flavors in fish sauce, fish soy sauce and light soy sauce. Sensors W5S, W1S and W2S had a relatively higher resistivity than others, and the W2S sensor played an important role in recognizing the first and the second principal components. These enabled the electronic nose to identify light soy sauce, fish sauce and fish soy sauce .The first and the second principal components were the same in all three sauces, but the contribution rate of ethanol and nitrogen oxides was different to the first and to the second principal components.