Abstract:The purpose of adding xylanase to wheat basal diet in this paper was to study the influences of xylanase on the quantity and composition of intestinal microflora, display the mechanism of xylanase promoting Oreochromis niloticus growth. Oreochromis niloticus were used as experiment objects in this study and their initial body weight was (100.39±17.83)g. Wheat basal diet was control. The tested diets were wheat basal diet added with different levels of xylanase (0.05%, 0.10%, and 0.15% respectively). Each treatment was devised with 5 repeats and each repeat had 40 male Oreochromis niloticus. The fish in floating cages were fed to satiation for 78 days. In this paper, we measured the amount of bacteria in intestinal of Oreochromis niloticus. Anaerobic bacteria were identified by BIOMERIEUX VITEKⅡ Automated Identification Systems and VITEKANA ID Kit. The results showed that the quantity and composition of intestinal microflora of Oreochromis niloticus were changed by dietary xylanase to wheat basal diets. The forgut quantity of aerobic bacteria of 0.10% and 0.15% xylanase groups were significantly lower than that of the control (P<0.05 respectively).The midgut quantity of aerobic bacteria of 0.05%, 0.10% and 0.15% xyanase groups were significantly lower than that of the control (P<0.05 respectively). The hindgut quantity of aerobic bacteria of the test groups were lower significantly than that of the control (P<0.05). The foregut quantity of anaerobic bacteria of 0.15% xylanase group was decreased by 76.85%, 75.62% and 75.83% compared with those of the control, 0.05% and 0.10% groups (P<0.05 respectively). The midgut quantity of anaerobic bacteria of 0.10% and 0.15% xylanase groups were lower significantly than those of the control and 0.05% xylanase group (P<0.05). The hindgut quantity of anaerobic bacteria of 0.05%, 0.10% and 0.15% xylanase groups were decreased by 13.13%, 48.30% and 60.62% compared with that of the control(P>0.05, P<0.05, P<0.05 respectively). The xylanase mainly influenced the proportion of Ent., Bac., Bact., Bif. and Lac.. The proportion of foregut Ent. of 0.05%, 0.10% and 0.15% xylanase groups were decreased by 13.16%, 29.61% and 49.34% compared with that of the control (P>0.05, P<0.05, P<0.05 respectively). The proportion of foregut Bac. of three test groups were significantly higher than that of the control (P<0.05). The proportion of Bac. in midgut and hindgut of 0.10% and 0.15% xylanase groups were higher than those of the controls (P<0.05). The proportion of foregut Lac. of 0.15% xylanase group was significantly higher than those of the control and 0.05% xylanase group (P<0.05 respectively). The proportion of foregut Bact. of the control was significantly higher than those of 0.10% and 0.15% groups(P<0.05 respectively). The proportion of midgut Bif. of test groups were increased significantly compared with that of the control(P<0.05). The proportion of midgut Lac. of 0.15% xylanase group was significantly higher than those of the control and 0.05% xylanase group(P<0.05). The proportion of midgut Bact. of 0.10% and 0.15% xylanase groups were decreased significantly compared with that of the control(P<0.05).

Abstract:A cDNA library was constructed from turbot, Scophthalmus maximus, spleen by unidirectional cloning. A total of 3 656 ESTs from the library were sequenced and compared with sequences in the GenBank database. 1 765 clones (48.3%) appeared to be completely unknown and are likely to represent newly described genes, whereas 1 891 clones (51.7%) were identified based on matches to sequences in the database. These identified clones were derived from at least 149 genes which were categorized into six categories: 9 in cell structure/motility (6.0%), 26 in metabolism (17.5%), 45 in cell defense/immunity (30.2%), 43 in gene/protein expression (28.9%), 16 in cell signal transduction/communication (10.7%), and 10 genes lacking enough information to be classified (6.7%). Immune related cDNAs identified from the spleen were: CC/CXC chemokine, MHC class Iα, complement component C1/C₃, natural killer cell enhancing factor (NKEF), thymosin beta4/ beta12, interferon inducible protein Gig1, ILB4 receptor, STAT4, and hot shock protein 70/90.

Abstract:540 grass carps ［initial body weight （8.25±0.37） g ］ were randomly divided into 6 treatments (90 for each treatment, 30 for each replicate) to investigate the nutritional physiological effects of dietary isoleucine on grass carp by feeding with six graded levels of crystalline isoleucine (0.77 g, 1.07 g, 1.37 g, 1.67 g, 1.97 g and 2.27 g per 100 g dry diet) which have the same isonitrogenous diets (35.25 % protein) with caseingelatincorn gluten mealcrystalline amino acid mixtures as protein source supplemented. Amino acid pattern in diet is to simulate the amino acid pattern found in the whole body protein of grass carp except for isoleucine. Each diet was randomly assigned to triplicate groups of 30 juvenile grass carp in freshwater floating net cages (1.0 m ×1.0 m ×1.0 m). After a 72day feeding trail, the results showed that: When the dietary isoleucine level was 1.67 % level, weight gain (WG), specific growth rate (SGR), protein efficiency ratio (PER) got the maximum and feed conversion rate (FCR) got the minimum (P<0.05); deinternal organ ratio (DOR) and condition factor (CF) got the maximum, viserosomatic index (VIS) got the minimum; moisture and crude lipid of body were minimum, protein and ash content of it were the maximum(P<0.05); Moisture of muscle was minimum, protein were the maximum(P<0.05), but the difference of crude lipid was not significant(P<0.05). When the dietary isoleucine reached 1.67 % level, both the content of isoleucine and total amino acids in the muscle were maximum. The RNA/DNA of muscle rose first and then went down, when the dietary isoleucine reached 1.67 % level, RNA/DNA of muscle were the maximum, and the difference was significant(P<0.05). Glutamate hydrogenase activity of liver went down first and then raise, when the dietary isoleucine reached 1.67 % level, glutamate dehydrogenase activity was the lowest, and the difference was significant(P<0.05). When the content of isoleucine went up, the blood ammonia was leveling off at the beginning, when the dietary isoleucine reached 1.67% level, the blood ammonia rose. The difference of the albumin in the serum was not significant(P<0.05). TG and CHO went down first and then rose, when the dietary isoleucine level was 1.67 % level, TG and CHO were the lowest, and the difference was significant among groups(P<0.05). The conic analysis of WG, SGR, FE and PER against dietary isoleucine level indicated that optimal dietary isoleucine requirement for juvenile grass carp was 1.46 %,1.49 %,1.45 %and 1.41 % of the diet (corresponding to 4.14 %, 4.23 %, 4.11 % and 4.0 % of dietary protein on a dry weight basis). So the range of optimal dietary isoleucine requirement for juvenile grass carp was 1.41%-1.49%(dietary base) or 4.0 %-4.23 %(protein base).

Abstract:The ubiquitinproteasome system (UPS) plays an important role in posttranslational process, which is responsible for a diverse array of biologically important cellular processes. The UPS is also involved in the protein quality control, which maintains the health of the cell. Thus, the UPS provides a clue for understanding of the molecular mechanisms underlying various tolerances of organism to diversiform adverse conditions as well as stress combination. Ubiquitinconjugating enzyme (E2) is a critical component of UPS. Cloning of ubiquitinconjugating enzyme gene (PyE2) of Porphyra yezoensis Ueda will facilitate us to investigate tolerance of P. yezoensis to diversiform adverse conditions and degradation of enable protein by UPS. cDNA sequence (GenBank accession: FJ232910) of PyE2 was isolated successfully through experiment of RT-PCR under direction of in silico cloning. This cDNA contained a 444 nt of complete open reading frame (ORF) coding a 16.6 ku protein (PyE2) of 147 amino acids sequence. PyE2 had significant amino acid sequence identity and similarity with E2s from other organism, which indicated E2 was highly conserved in the evolution. PyE2 contained conserved sequence and cysteine residue of active site of E2 family, and tertiary structure of PyE2 was similar to human class I E2. PyE2 was a class I member of E2 family of P. yezoensis according to bioinformatics analysis.

Abstract:Foodborne pathogenic microorganism compositions of tilapia and their cultivation environment which were from different areas of Guangdong Province were analyzed. Methods: Using different selective media，the Merieux Microbiological system and microorganism automation appraisal system to separate and identify foodborne pathogenic microorganism. The results showed: The species of foodborne pathogens varies with the season change，most the types of pathogens in the summer and less in the spring. The numbers of pathogenic species of fish body and its culture environment are 11 and 12 in the summer, respectively. And in the spring, the number of pathogenic species of fish body is only six. Pathogenic Aeromonas hydrophila, diarrheogenic Escherichia coli, Salmonella are mostly common in tilapia and their cultivation environment each season. Detection rate of pathogenic Aeromonas hydrophila was higher in spring and summer, of which 83%-89% in cultivation environment and 44%-67% in fish. The detection rate of diarrheogenic Escherichia coli was 83%-100% in spring, summer and autumn from cultivation environment and was 48%-67% in summer and autumn from fish. The detection rate of Salmonella was 33%-39% from cultivation environment and was 44%－52% from fish in spring and autumn. The other foodborne pathogenic microorganisms have been identified from fish such as Vibrio cholerae, Vibrio parahaemolyticus, Vibrio vulnificus, Enterobacter cloacae, Enterobacter sakazakii, Pseudomonas aeruginosa, Pseudomonas putida and so on. The aim of the survey is to provide theoretical basis for predictive foodborne pathogenic microorganism in tilapia.

Abstract:Sequencerelated amplified polymorphism (SRAP) markers were used to examine the genetic variation of three consecutive generations (F₁, F₂ and F₃) and one backcross generation (BC₁) in pearl oyster Pinctada martensi family with redcolor shell. A total of 63 bands were generated with 7 primer pairs, among which 55 were polymorphic bands. On average, 7.86 polymorphic loci were generated with each primer pair. The Shannon information index and the Nei’s gene diversity indexes in the F₁, F₂ and F₃ showed a reduction in genetic diversity, with no significant difference in genetic diversity among generations (P>0.05). With the increasing of generations, the differentiation between contiguous generations showed a inclination of reduction, but genetic identity within generation increased. The genetic similarity between BC₁ and F₁ was higher than that between F₃ and F₁, and the result showed that offspring inclined to recurrent parent by backcross. The results would provide theoretical guidance to the farming and breeding of pearl oyster.

Abstract:Genotype segregation of parents livestocks (G₀ generation)and their offspring (G₁ generation)of 6 Litopenaeus vannamei families was analyzed on basis of 7 microsatellite DNA markers.In addition, heterogeneity analysis for pairwise comparisons of expected heterozygosities (H_e) of all loci between G₀ and G₁ was carried out and genetic differentiation through F-statistics at each locus in G₁ population was expected to monitor genetic variation in Litopenaeus vannamei breeding. The results showed that 44 alleles were detected in total across 7 loci assayed,mean number per locus,mean expected heterozygosity and mean polymorphism information content of G₀ generation were 6.14, 0.786 and 0.709 respectively, and those of G₁ generation were 6.27, 0.733 and 0.695 respectively. The combined exclusion probability of 7 microsatellite markers arrived at 0.99 and could seperate all 6 families with known parent. Heterogeneity analysis for pairwise comparisons of expected H_e of all loci between G₀ and G₁ indicated that H_e of G₀ was significantly higher than G₁(P<0.01). F_ST of G₁ per locus ranged from 0.270 3 to 0.465 4 and average was 0.358 4 which meant that genetic differentiation in its subpopulation was high. The UPGMA analysis based on six families genetic distances showed all individuals of G₁ generation could be classified into 4 categories.Similarly to families C and D, families A and B sharing father had high similarity coefficient and clustered together, family E and F were assigned into another group respectively.

Abstract:In this study, two mitotic gynogenesis families GF1 and GF2 were produced and verified with 10 microsatellite markers，8 in GF1 and 4 in GF2 respectively. The inheritance and segregation of 10 microsatellite loci in putative gynogenetic doubled haploids (GDH) were investigated. All of fries in control families were abnormal, while normal fries reappeared in GF1 and GF2 after hydrostatic pressure shock, with normality rate of 40.0% and 17.1% respectively. In GF1, twenty genotypes have been observed in 30 assayed progenies. All samples of GF1 were demonstrated as GDH for exclusive maternal inheritance and homozygous at each locus. In 30 tested offspring in GF2, 27 fries were demonstrated as GDH, 2 fries contained male parent specific band, and 1 fry remained undefined. These results suggested that the homozygous gynogenesis could be induced with the method reported in this paper. In addition, the segregations of microsatellite markers in GDHs were consistent with the expected ratio according to Mendel’s law at all the loci except LYC0026 and LYC0053. We also found that the segregation mode of GDH was completely identical between LYC0002 and LYC0014. In the present study, the artificial induction of homozygous gynogenesis and the inheritance and segregation of microsatellite markers in GDH in large yellow croaker was first reported, which will server as a foundation for rapid establishment of homozygous lines and making a genome map with GDH and homozygous lines in large yellow croaker.

Abstract:Eight stable monoclonal hybridomas were successfully produced by immunization of Balb/C mice with purified softshelled turtle iridovirus (STIV) antigen. The Mabs obtained were three kinds of isotype. Mab 2A4 was subclass IgA, Mab8E1 was subclass IgG2a, and the other Mabs 1D3, Mab2H1, Mab3A1, Mab4B5, Mab5E1 and Mab6F2 were subclass IgG1. ELISA(enzyme linked immunosorbent assay) assays showed that eight Mabs could specifically recognize the antigen of STIV, and had no cross reaction with the cell lines EPC, Co, FHM. The ELISA titers of ascites were between 10⁵ and 10⁶. Immunofluorescent studies showed that all Mabs (except for Mab5E1) had fluorescence characteristics, and the specific fluorescence signals appeared in the cytoplasm of STIVinfected (EPC) cells. None of the Mabs possessed the ability to neutralize STIV in vitro cell cultures. In this experiment, Westernblot was used to analyze the epitope of monoclonal antibodies against STIV. It demonstrated that Mab1D3 and Mab2A4 reacted specifically to a single linear protein with an approximately molecular weight of 84 ku and 35 ku respectively, Mab3A1 reacted with two STIV proteins at molecular weight of about 14 ku, 16 ku. The results suggested that these three Mabs target conformationindependent determinants within STIV protein. The identity of the target antigen of the other five Mabs could not be determined by Westernblot. These Mabs against STIV might be specific and sensitive, and they might also be used to detect STIV and analyze its structure proteins.

Abstract:Studies on the eggs and embryonic development of Chiloscyllium plagiosum showed that the eggs were big, the egg yolks were oval,with the longer diameter of 25.91-36.16 mm and the short diameter of 13.56-19.44 mm. The eggs covered by brown, leathery with a little malleable, and opaque external shell with the longer diameter of 75.25-107.30 mm, the short diameter of 33.39-47.70 mm and the thickness of 15.82-24.65 mm. Under water temperature of 28.0 ℃ and salinity of 26.2-28.8, the young fish hatched between 65 and 80 d after deposition. The embryonic development of Chiloscyllium plagiosum was divided into 23 stages with suitable names.The toal length of the newly hatched young were 121.82-166.80  mm, while the body mass were 5.30-18.22 g. The yolk remained just a little or nothing at all out of the body, but there were yolk inside the body. They had the figure of the adult fish. There was a significant linear correlation between toal length（L/mm）and incubation time（D/d）：L=2.1368D－11.175（R=0.9862）,while a significant curvy correlation between body mass（M/mg）and the accumulative time（D/d）：M=0.0001D^4.3763（R²=0.9579）. The curve between body mass（M/mg）and toal length（L/mm）was fitted by M=0.0005L^3.4278 (R²=0.9822）.

Abstract:Protein phosphorylation and dephosphorylation are the most important regulatory mechanisms governing many aspects of biology. Phosphoproteome studies have revealed that phosphorylation and dephosphorylation modulate functions of more than one third of the total cellular proteins. In eukaryotes, dephosphorylation at serine/threonine residues are executed by four major protein phosphatases, Phosphatase-1(PP-1), Phosphatase-2A(PP-2A), Phosphatase-2B(PP-2B), Phosphatase-2C(PP-2C), and several minor phosphatases including Phosphatase-4(PP-4), Phosphatase-5(PP-5), Phosphatase-6(PP-6), and Phosphatase-7(PP-7). Among these different phosphatases, Protein Phosphatase-1(PP-1) is one of the most important protein serine/threonine and plays distinct roles in regulating gene expression, signal transduction, cell proliferation, differentiation, transmission, apoptosis, autophagy, morphogenesis, organogenesis and other cellular activities. Our previous studies have demonstrated that PP-1 is a major phosphatase that dephosphorylates Pax6 to modulate its function in regulating brain and eye development. More recently, we have established the expression patterns of the catalytic subunits and the regulatory subunits for PP-1 in mouse eye. To explore the possible functions of PP-1 in various tissues of the lower vertebrates, here, we have analyzed the differential expression patterns and the cellular localizations of the catalytic subunit for PP-1 using western blot and immunohistochemistry on four different ploidy fish: the allotetraploid hybrids and their diploid parents, common carp (♂) and red crucian carp (♀) as well as the triploid crucian carp derived from crossover between the allotetraploids and common carp or between the allotetraploids and the red crucian carp. Our study demonstrated the following results: (1) PP-1c is expressed in the brain, heart, muscle, kidney, liver, and gonads with defined differential expression patterns. (2) The most striking feature is that a relatively higher level of PP-1c expression was found in the muscle of the above fish. (3) Compared among the muscle tissues from 4 types of fish, the lowest level of PP-1c expression was detected in the allotetraploid fish, an intermediate level of PP-1c detected in both parents and the highest level of PP1c observed in the triploid crucian carp. Such a pattern illustrates its variability between filial generation and the corresponding parents. (4) The immunohistochemistry study revealed similar localization of PP-1c in certain groups of cells within the same tissue from the four different organisms. Together, these results lead to the following conclusions: (1) PP-1c is differentially expressed in various tissues of the four different ploidy level fishes; (2) PP-1c functions are highly regulated in different tissues; (3) Within the same tissue of the four types of fish, PP-1c is localized in the same types of cells; and (4) the presence of strong PP-1c immunofluorescence signal in certain nuclei of neurons in both allotetraploid and triploid brains but not in those of the diploid parents indicates that PP-1c may be used as a biochemical marker to distinguish the different types of fish. In summary, our results represent the first report on the differential expression patterns of the protein phosphatase-1c in six tissues from the different ploidy level fish, and provide valuable information for the future study of the PP-1c functions in these organisms.

Abstract:Siberian sturgeon Acipenser baeri is one of the most popular fresh water aquaculture species in China. Artificial spawning of this species has succeeded. In order to provide information that may help with the improvement of fry rearing techniques, the morphological observation during postembryonic development of Siberian sturgeon Acipenser baeri (F₂) were studied under rearing conditions. Newborn prelarval (0 day age) ［mean ±SD full length (FL) (9.16±0.21) mm］ was conducted till the age of 53 days (87.12±1.92) mm. According to morphological development, postembryonic development of Siberian sturgeon was divided into two different phases, the prelarval stage between hatching (0 day age) and first feeding (9day age ), and the larval stage between the initiation of external feeding and metamorphosis (37day age ). During the prelarval stage, the differentiation and morphological development of respiratory, swimming, sensorial and feeding systems were very intense, while the larval period as characterized by the development of dorsal, lateral and ventral rows of scuta. Morphogenesis and differentiation were more intense during the prelarval than larval and early juvenile stages. Such abrupt changes on growth patterns were related with improvement on respiration, feeding and swimming ability. Rapid development of those functional systems helped larvae escape from predators and get external food efficiently, which contributed to its survival. For the improvement of artificial fry rearing technique, specific conditions should be provided in time which depend on the early life stage growth patterns, so that important organs might have priority to develop normally and survival rate of early life stage might increase.

Abstract:This study used suppression subtractive hybridization (SSH) for construction of the cDNA subtractive library of the liver from the living body infected Hyriopsis cumingii plague virus. After testing, differentially expressed genes were enriched in the 2¹⁰ times that the proof of the cDNA library has strong subtractive efficiency. Three hundred positive clones were randomly picked and identified by PCR method; 95% clones contained 0.2-1.0 kb by inserts,which might be the cDNA frag menu of differentially expressed genes in Hyriopsis cumingii plague virus infected group. Three hundred clones were sequenced and obtained 214 known function EST for 58 different genes were reported in H.cumingii for the first time in this study. According to the classification of functional genes by Adam,the identified EST in H.cumingii fell into eight categories relevant to 2 belong to cell division genes, 9 belong to cellular structure and movement genes, 10 belong to metabolism genes, 7 belong to signal transduction genes,10 belong to cell immuneaction genes, 20 belong to gene and protein expression associates genes and 26 belong to other proteins with unknown functions.In addition,there are 14 no similar sequence in Genbank, conjecturing its new genes. Results show, the method to construct cDNA subtractive library could well reflect the gene information of abalone affected by H. cumingii plague virus. Results of the present study provide the basic data to research of relationship between resistance breeding and gene expression of liver.

Abstract:In this paper, the optimization for blade photosynthesis and culture conditions at different light intensity and temperature in Ulva linza with pulse amplitude modulation chlorophyll fluorometer (PHYTO-PAM). The results showed that F_v/F_m, F_m, F_v and α value were the highest at 25 ℃ temperature and 72 μmol/(m²·s) light intensity, up to 0.74, 4567, 3406 and 0.305 respectively. When temperature and light intensity were lower than the point, light unsaturation would occur. And the farther the temperature and light intensity was from the point, the greater their F_v/F_m, F_m, F_v and α value decreased (P<0.01). At 5 ℃ and 35 ℃ with 72 μmol/(m²·s) light intensity, the F_v/F_m, F_m, F_v and α values were the lowest, about 32.24%-64.88% and 22.99%-53.44% of that at 25 ℃ with 72 μmol/(m²·s) light intensity, respectively. And at 18 μmol/(m²·s) and 216 μmol/(m²·s) light intensity with 25 ℃, the F_v/F_m, F_m, F_v and α values also were lowest, which were 44.94%-82.62% and 51.82%-76.72% of that at 72 μmol/(m²·s) light intensity with 25 ℃, respectively. F₀ did not change much. At 5-30 ℃, F₀ first increased and then decreased or increased again, while at 35 ℃, it firstly declined and then increased. As for fitting parameter α, it was showed that Ulva linza enhanced photosynthesis by increasing light energy absorption before light saturation point, but after that, they would increase photosynthesis by rapid declining light energy absorption. rETRmax Duncan test showed that the high / low temperature and high light intensity inhibited photosynthesis rate significantly (P<0.01). It indicated that the temperature between 15 ℃ and 25 ℃ and light intensity between 54 μmol/(m²·s) and 72 μmol/(m²·s) were feasible photosynthesis and growth conditions for Ulva linza, and too high or too low were not good. The temperature order for photosynthesis and growth rate was 25> 20> 15> 30> 10> 5> 35 ℃, and the light intensity order was 72>54/108>36/162>18/216 μmol/(m²·s).

Abstract:Nitrobenzene is an important chemical raw material. Owing to human activities of production and living, it may become the pollution source of the water and the environment. In order to understand the possible toxicity of nitrobenzene to aquatic animals, the DNA damage of the nitrobenzene was studied at different concentrations to the liver and pancreas, kidney, fin, sperm cell of zebrafish by singlecell gel electrophoresis technique. When the treatment dose of nitrobenzene was at the national standard for surface water environmental quality（GB3838-2002, 0.017 mg/L）, the DNA damage of the liver and pancreas, kidney and sperm cell was not obvious, being 30%, 33% and 44% respectively. The results were no significant difference compared with the control group（P>0.05）. In the same concentration, the DNA damage rate was as high as 69% for epidermal cells of fins. When the concentration of nitrobenzene was higher than the national standard, it caused the serious DNA damage to the liver and pancreas, kidney and sperm cell. When the concentration of nitrobenzene was 0.106, the damage rates were 48%，62%，61%，82%；at 0.213 mg/L those were 42%，87%，76%，56%； those were 52%，87%，75%，75% at 0.425 mg/L； those were 58%，95%，93%，85% at 0.850 mg/L； those were 62%，90%，99%，83% at 1.700 mg/L respectively. All the treatments concentration above the national standard were significant differences compared with the control group（P<0.05）. The result showed that the nitrobenzene had no obvious toxicity to the somatic cells and the sperm cells of the zebrafish when the concentration of nitrobenzene in the water environment was lower than the national standard. When the concentration of nitrobenzene was higher than the national standard, the nitrobenzene had stronger toxic effect on the somatic cells and the sperm cells of the zebrafish, and the DNA damage rate rose with the nitrobenzene dose increasing, and it presented the specific dose of the damage effect. So the concentration of nitrobenzene in fishery water standard should not be higher than the national standard.

Abstract:Jumbo flying squid (Dosidicus gigas) distributed in the southeastern Pacific is not only an important economic oceanic squid, but also one of the important fishing targets for Chinese jigging fleets. The researches on distribution of this squid and its relationship with environmental conditions such as water temperature and its structure are the key content in searching for the mechanism of fishing ground and inherent laws. In this study, based on the fishing data from Chinese squid jigging fleets in the waters off Peru from January to December 2006, and the environmental data including sea surface temperature (SST), the water temperatures between 5 and 180 m, and the horizontal gradient of temperature (D) calculated by three different methods (D_max, D_square and D_mean), the spatial plots of CPUE, SST, D and the vertical temperature structure are drawn respectively by use of software ArcGIS 9.0 and Sufer 8.0 to analyze the distribution of fishing ground and its relationship with structure of sea water temperature. The result indicated that the main fishing ground was around 80-85°W and 10-17°S with the range of 18-28℃ SST, and the spatial variations in the catch distribution were evident. From June to August, the monthly catch was relativly high in the waters of 81-83°W and 12-13°S with the range of 18-23 ℃. The distribution of fishing ground was closely related to the D, the indicator D_square (P<0.001) was better than the two others, and the range of D_square was 0.6-1.7 ℃ in the main fishing ground. The results also showed that the upwelling was centralized around 12-13°S and 81°W during June to August, and the fishing ground was mainly distributed at the edge of upwelling between 81°30′-82°30′W. Therefore, it could be concluded that the fishing ground was formed by the upwelling, which was distributed at the mixed region between oceanic warm water and cool water caused by upwelling, and was closely related with the optimum SST, D and vertical temperature structure.

Abstract:A largemouth bass ulcerative disease broke out in the summer and autumn of 2008 at Foshan area of Guangdong Province. The clinical signs of this disease were a great size of ulcer and necrosis on body surface and inflamed fin bases. The ulcerative disease broke out quickly and caused a high rate of mortality, which led to large losses for many largemouth bass breeding farms and threatened its aquaculture industry. So it was necessary to find out the cause of this disease and take corresponding countermeasures for prevention and cure or diagnosis. In this research, in order to identify the pathogen of largemouth bass ulcerative disease, five Aeromonas hydrophila strains were isolated from the muscle of diseased fish for artificial infection. Experimental infection under aquarium conditions suggested the infected largemouth bass did not show any clinical sign. The homogenated muscle ultrafiltrate from diseased fish with no bacteria was prepared and injected into healthly largemouth bass. 7 days later, these treated largemouth bass showed typical symptoms of ulcerative disease similar to ehose of natural diseased fish. The muscle specimens of artificially infected and naturally diseased largemouth bass were prepared and made into ultrathin sections for observing the morphological character of the pathogen. Electron microscopic observation showed that a large amount of viral particles existed in the cytoplasm. The maturated particles were enveloped and had hexagonal outline. The diameter of these virions was about 145.5 nm. A pair of primers based on the conserved region of the reported iridovirus major capsid protein（MCP）gene was designed, and a 530 bp fragment was amplified from the DNA extracted from the muscle of artificial infected largemouth bass and sequenced. The amino acid sequence showed 39.5％-100％ homology with the MCP gene sequences of other iridoviruses. Both electron microscopic observation and MCP gene sequences analysis results showed the virus belonged to the genus ranavirus of family Iridoviridae，which was different from LMBV on molecular character and induced clinical signs. These results indicated that this virus was the lethal pathogen of largemouth bass ulcerative disease. The ulcerative disease reported here was designated temporally largemouth bass ulcerative syndrome.

Abstract:Habitat preference plays an important role in the life of fish. Illumination intensity preference and its effects on feeding efficiency of juvenile Chinese sturgeon, Acipenser sinensis were studied by Single Factor Experiments．The result shows that the percentage of time spent by Juvenile Chinese sturgeon in dark area(1.4-2.2 lx), transition area(10.4-12.3 lx) and illuminated area (200.2-209.1 lx) are (1.32%±3.50%) , (7.17%±13.5%) and (91.52%±14.9%) respectively; and the number percentage of the fish in three areas are (6.42%±4.13%)，(14.2%±7.45%) and (82.38%±15.2%). Juvenile Chinese sturgeons are photopositive significantly (KruskalWallis Test, P<0.05). The typical behavior of juvenile Chinese sturgeon in the illuminated area is circling movement around the light source. The behavior type is coincident with the mechanism of fish phototaxis of ‘signaladaption hypothesis’. When provided 206 lx illumination intensity, the feeding consumption(Fc), feeding intensity(Fi) and feeding rate(Fr) of juvenile Chinese sturgeon on Rhinogobius giurinus were (9.67±2.08), (0.97±0.21) and (0.24±0.05). When illumination intensity were 0 lx, the value of Fc, Fi and Fr were (10.67±2.31), (1.07±0.23) and (0.27±0.06). The feeding efficiency of juvenile sturgeons were not significantly different between two illumination conditions(P>0.05, MannWhitney Test). The result shows that feeding behavior of juvenile Chinese sturgeon might not be dependent on vision.

Abstract:Floating collar, an important component of deepwater net cage, plays a great important role in the performance of withstanding strong winds and waves for net cage, and studying the movement characteristics of floating collar exposed to waves is a key to deeply understand the properties of withstanding strong winds and waves about net cage. In this paper, based on the lumped mass method, floating circular collar is discreted with lots of microelements, and by using the linear wave theory and the rigid body kinematics principle, a numerical model for movement response of floating collar exposed to waves is set up. Reference to practical floating collar parameters: 40 m in circumference, 12.7 kN in total weight, 15 m in water depth, r=125 mm, t=15 mm,ρ=953 kg/m3. Under the conditions of different wave heights（H=4.2-7.0 m）and wave periods（T=7.2 s, 8.6 s）, the motion trajectories of the fore and rear points of the floating collar, the horizontal and vertical displacement of the central point of floating collar, pitch angles of floating collar are calculated in the way of computer numerical simulation method. By comparing and analyzing, the calculated results show that:（1）The vertical motion amplitude of the collar is greater than the horizontal one, and the influence of wave period on the vertical displacement of the collar is less than that of the horizontal one;（2）The horizontal displacement, the vertical displacement and the pitch angle of the collar all have direct proportional relation with wave height. Under the condition of wave height of 4.2-7.0 m, the increase of the horizontal displacement, the vertical displacement and the pitch angle of the collar are 1.84 m, 1.0 m and 7.18° when T=7.2 s, while they are 1.66 m, 1.05 m and 5.43° when T=8.6 s;（3）When wave period increases, the vertical displacement of the collar increases accordingly, while the horizontal displacement and the pitch angle of the collar decrease.

Abstract:Stable isotopes have been used in many research areas as natural labels, and are becoming the more appropriate option for the aquatic ecological studies. An organism’s stable isotope ratios (δ¹⁵N and δ¹³C etc) are an integration of the isotopic signatures of preys that have been assimilated through time, the organism will come into isotopic equilibrium with its diets depending on growth and tissue turnover rates, and the ratios can change with different food, are good labels of organism living conditions. According to the carbon stable isotope ratio of organisms from Changjian Estuary and adjacent Southern Yellow Sea in spring, we calculated their feeding habits. It is found that, (1) the feeding habits of some organisms calculated with stable isotope method or stomach analysis method in Changjians Estuary and Southern Yellow Sea were different, we could speculate that the energy sources of the two areas were different or some organisms could change with the habits, change their food sources with time and areas; (2) if the feeding habit types of stomach isotope analysis method was the same to that of stable isotope technique, only three organisms had different feeding habits in twentyfour common organisms, which showed the table isotope technique could be used to calculate the feeding habit of organism, and it had many advantages in calculating feeding habits of organism in different areas or time.

Abstract:Using the amount of vessels, gross tonnage, total power and professional fishing labor as four input indexes, the total fishing yield in a year as an output index, the fishing capacity and the capacity utilization of Chinese inshore and pelagic fleets were systematically measured by the data envelopment analysis (DEA) method from 1994 to 2005. Based on the calculated results, the policy performance carried out by Chinese fishing managers was quantificationally analyzed for Chinese inshore fishing industry in these years. The research showed: the fishing capacity of inshore fleets was increased before 2000; it was decreased and had been curtailed about 8% from 2001 to 2005. It displayed that Chinese inshore fishery management achieved some effect in these years. According to the research on the fishery input by inputoriented DEA method, the rate of surplus for the amount of fishing vessels and the professional fishing labor has been better controlled than for the gross tonnage and total power to Chinese inshore fleets. It showed that the inshore fishing capacity has been mainly enhanced by the increasing fleets′ power and tonnage at present. It should be attached importance by the related managers. Comparing the inshore fishery to pelagic industry, the research affirmed: there is more than 50% surplus for Chinese inshore fleets. The capacity utilization of these inshore fishing fleets is not ideally high enough and its increased extent will be limited. Contrarily, the fishing capacity utilization of pelagic industry will be more probably promoted than the inshore fleets′. Although the ratio of capacity output of pelagic industry to inshore fishery was heightened from 0.10∶〖KG-*2〗1 to 0.17∶〖KG-*2〗1, but the fishing capacity of pelagic industry has not come to 20% to the inshore fishery. It indicated that Chinese pelagic industry is now still in an elementary phase. At the same time, the research also found that there is a closer trend for the capacity utilizations between the inshore fleets and pelagic industry after they parted from each other. It may be explained that the inshore fishing fleets will be attracted to go to ocean if the capacity utilization of pelagic industry is high enough. This will lighten the pressure of the inshore fishery resources. So it resulted in the fact that the capacity utilization of inshore fleets was increased and the capacity utilization of pelagic industry was decreased. On the opposite, if the capacity utilization of pelagic industry was lower enough than the inshore fishery, some fleets will switch into the inshore fishery instead of pelagic fishing. It will increase the pressure of the inshore fishery resources and reduce the fishing capacity utilization of inshore fishery. Hereby the development of pelagic industry will directly influence the inshore fishing capacity. So improving and holding the high efficiency for pelagic industry would be useful to control inshore fishing capacity. Atfention should be paid to this problem by our administration departments.

Abstract:In April of 2006, the firstgeneration selected group (SG) was established by selecting eleven breeders with yellow shell color in Liusha Bay stock of pearl oyster Pinctada martensii. A control group (CG) was also obtained by randomly selecting fifty mature individuals in the same stock as breeders. In October of 2007, the individuals with the uniform size were separately sampled from the SG and CG groups and differences in physiological indices such as oxygen consumption rate and NH3 excretion rate between the two groups were evaluated at different temperature and salinity levels. The results obtained from this experiment included (1) oxygen consumption rate (OCR) and NH3 excretion rate (NR) were positively correlative to the temperature. Under the test temperatures, the increasing OCR and NR values of the SG covered the range of 0.117-1.009 mg / (g·h) and 0.013-0.028 mg / (g·h), while those of the CG were 0.142-0.827 mg / (g·h) and 0.016-0.028 mg / (g·h). (2) No significant differences of OCR and NR were found in the two groups at 15 ℃ (P> 0.05). At 20, 25 and 30 ℃, however, the SG displayed higher oxygen consumption rate and NH3 excretion rate than the CG, with significant differences observed in oxygen consumption rate at 30 ℃ (P < 0.05). (3)Q₁₀ respiration and )Q₁₀ excretion of the SG were 4.87 and 1.91 respectively; while those of the CG were 3.54 and 1.46. The average O/N ratios of the SG and CG were observed at 20.50 and 19.56. (4)At test salinity of 20-36, OCR and NR of the two groups increased with the increasing salinity, and reached the peak value at salinity of 28, and then the values decreased beyond 28. The OCR of the SG was in range of 0.435 to 0.678 mg / (g·h) while that of the CG was 0.233 to 0.671 mg / (g·h). The NR value of the SG covered the range of 0.011 to 0.027 mg / (g·h), and that of the CG 0.014-0.025 mg / (g·h). (5) At salinity 24, 28, 32 and 36, the SG had higher oxygen consumption rate than the CG, with significant differences observed at salinity 20, 24 and 36 (P < 0.05). The SG had higher NH₃ excretion rate than the CG at salinity 28 and 32, while the SG had lower NH₃ excretion rate than the CG at salinity 20, 24 and 36. (6) At salinity 20-36, the average O/N ratios of the SG and the CG were 34.50 and 25.01 respectively. The present results indicate that there exist evident differences in physiological indices between the SG and CG after one generation selection for yellow color, which will provide some useful information for further breeding in the groups.

Abstract:Starry flounder (Platichthys stellatus) is the large carnivorous fish and demands diet with high level protein. This experiment was carried out to study the effect of replacing fishmeal with new protein sources in diets of juvenile starry flounder ［initial weight, (75.6±0.18) g］. Five isonitrogenous and isoenergetic diets (D0, D17, D35, D52 and D69) were formulated by regulating amino acid level with new protein resources (soy protein concentrate, dephenolized cottonseed protein, spraydried blood meal, etc). D0 with 58% defatted fishmeal as the control group, fishmeal was replaced by new protein sources at four levels of 17%, 35%, 52%, 69%. Five groups in triplicate were divided randomly for the 60day experimental period. At the end of the experiment, growth performance, body composition and partial immunological parameters were studied. The results show that weight growth rate(WGR), protein efficiency ratio (PER) and specific growth rate (SGR) of D0 are 141.84%，229.88%and 1.47%/d，respectively, no significant differences occurred among D17, D35 and D52 (P>0.05), but D69 is significantly low at 107.77%,186.37% and 1.22%/d (P<0.05), respectively；Feed conversion ratio (FCR) of D0 is 0.80 and not significant to D17, D35 and D52(P>0.05), but D69 is 0.98 and higher than the other four groups obviously(P<0.05)；Digestive tube index(DTI) tends to enhance with increasing level of new protein sources，D0 is 2.01% , significantly lower than D69(P<0.05); Condition factors (CF) has no significant difference (P>0.05) in five groups. There are no significant differences (P>0.05) in the contents of protein and fat in whole fish and muscle，while the mineral content in whole fish increases with the replacement of fishmeal；erythrocyte, leukocyte，hemoglobin and serum protein have no significant difference(P>0.05) among groups，but increase of new protein sources has some negative impact on hematocrit(HCT) and lysozyme activity. These results show clearly that dietary fishmeal levels can be considerably reduced without any adverse effect on growth performances for juvenile starry flounder. Digestive enzyme activities, amino acid and the utilization of minerals of juvenile starry flounder are the target of research at present.