Abstract:Genetic diversity of the first filial generation of two cultured populations of Platichthys stellatus from South Korea (S) and Russia (R) was examined. Eleven from 40 random primers were used for population genetic analysis, and a total of 57 clear RAPD bands ranging from 300 to 2500 bp were recognized. The numbers of polymorphic bands of S and R populations were 33 and 32, respectively, and the mean percentages of polymorphic bands of them were 57.89% and 56.14%, Nei's diversity index of them were 0.230 5 and 0.194 7, and Shannon information index of them were 0.338 4 and 0.296 3. Partitioning analysis of genetic diversity in Shannon index indicated that 74.65% of genetic variation was distributed within populations and 25.35% was between populations.

Abstract:Pathological study on Scophthalmus maximus affected by an iridovirus in China revealed that the most prominent and consistent characteristics of this disease were the basophil enlargement of cells, mainly in the spleen, and also in the kidney, intestine, liver, gill, heart and skin. There were various pathological changes to the tissues associated with iridovirus. The spleen suffered the marked pathological changes with the heavy necrosis of hematopoietic tissue. In addition, necrosis of hematopoietic tissue in kidney, haemorrhage and oedema in submucosa of intestine, hydropic degeneration of hepatic cells, local necrosis of cardiac muscle and hemorrhage with inflammatory exudation in dermis were also observed. Electron microscopy showed that numerous viral particles were present in the enlarged cells. The viral particles were distributed in the cytoplasm, tissue interstice and lument of blood vessel. Cells infected by the virus presented obvious cytopathological changes. The mitochondria and endoplasmic reticulum fragmented and dissolved in the swollen cytoplasm. The haemorrhage in subcutaneous tissue with virus infection was responsible for the reddish appearance of diseased turbot. Anaemia caused by the virus infection was the main cause of death in affected fish and organ failure as a result of tissue necrosis also accelerated the death of diseased fish.

Abstract:Combined with artificial breeding techniques of Sepiella maindroni, embryonic development of Sepiella maindroni was observed under microscope or anatomical lens by peeling off egg membrane of fertilized eggs. Egg of S.maindroni was anisolecithal and adhesive, and black in color. Its egg membrane was tertiary egg membrane; it showed meroblastic cleavage, and was discoblastula and directive occurrence type. The incubation period was from 14 d to 23 d at temperatures of 23.8-26.2 ℃, salinity 29.3, and the peak hatching time was 18~21 d. The hatching rate was 83.1%, accounting for 79.4% of the whole amount of hatched larvae. The speed of embryonic development was positively connected with water temperature (20-30 ℃), and the hatching rate greatly decreased when salinity was lower than 22.

Abstract:The classification and relationships of Pampus have been disputed for almost 200 years. The confusion and debates have brought much trouble to the study of phylogenetic relationships. Lately, some researchers partitioned Pampus into 5 species according to the morphological specializations in China seas. In this study, to evaluate the phylogenetic relationship of 3 species (Pampus argenteus, P. punctatissimus, P. chinensis) from the China Seas, the mitochondrial cytochrome b-gene of 19 individuals were amplified using PCR techniques. About 1150bp length fragments were obtained and sequenced. After being aligned, a fragment of 1 123 bp nucleotide sequence which could be used for sequence analysis was obtained. The genetic information indexes, including Kimura-2 parameter genetic distance, basal composition and phylogenetic trees were generated using MEGA3-1 software. Of the 1 123 aligned base pairs, 141 sites were variable. The mutation sites were mainly transition and transversion. Transitions were found to be more common than transversions which suggested that the sequences had not reached saturation. The average basic compositions of all sequences were as follows: 29.1% T, 30.5% C, 27.4% A, and 13.0% G. Of the 19 sequences we defined 11 haplotypes. The genetic distances between haplotypes ranged from 0.1% to 11%. The sequences were combined with homologous sequences of Peprilus medius, Stromateus stellatus and Psenopsis anomala downloaded from GenBank. Molecular phylogenetic trees were constructed by neighbor joining (NJ) and minimum evolution (ME) methods based on the 1 123 bp Cytb gene sequences, with P. anomala as the designated outgroup. Both NJ tree and ME tree indicated a closer relationship between P. punctatissimus and P. chinensis and a farther relationship between P. argenteus and the above two species. P.anomala was basal in the NJ and ME tree and diverged before Stromateidae. The result is consistent with the conclusion of morphological analysis.

Abstract:Studies on the oxygen consumption rate, its diurnal variation and asphyxiation point of rock bream Oplegnathus fasciatus at different salinities (20, 25, 30) and temperatures (15℃, 20℃, 25℃) were carried out in Qingdao Zhonghai Fishery Corporation, Ltd. from April to August, 2008. The experimental fish were divided into two groups: 70d-old group at an average body weight of 1.07g and an average body length of 37.68 mm; 105d-old group at an average body weight of 5.59g and an average body length of 65.71 mm. The results showed that relative oxygen consumption rate of 105d-old fish was significantly higher than that of 70d-old fish, while the asphyxiation point of the former was lower. The oxygen consumption rate of rock bream decreased as their body weight increase. Both relative oxygen consumption rate and individual oxygen consumption increased with the rise of water temperature when salinity was unchanged. The effect of salinity on oxygen consumption rate of 70d old fish was significant (P＜0.05) whereas it was not significant for 105d-old fish (P＞0.05). The optimum salinity for growth of rock bream was 25, and the optimum temperatures were 20～25 ℃. The asphyxiation point of rock bream were between 1.602 1 mg O2/L and 2.953 8 mg O2/L at different temperatures and salinities and it decreased with the increase in body weight. Neither salinity nor temperature had significant effects on which (P＞0.05). The oxygen consumption rate of the young fish was 0.945 9 mg O2/g.h in daytime, which was about 3-5 times higher than the nighttime. Rock bream showed high metabolism rate till 22∶00pm. 

Abstract:The first generation of four broodstock combinations, C (♀) ×C (♂), J (♀) ×J (♂), J (♀) ×C (♂) and C (♀) ×J (♂) were obtained from mating and crossing within and between Japanese broodstock (J) and China disease resistante broodstock (C) of Japanese flounder Paralichthys olivaceus using complete diallel crosses. Comparisons of fertilization rate, hatch rate, albinism rate and survivorship were made among four treatments in this study. Heterosis and correlations were found in different characteristics. The results showed that there were significant differences between the hybridization groups and self-fertilized groups on albinism rate and survival rate. Heterosis on hatch rate reached 33.99% and heterosis on survivor rate reached 31.37% in C (♀) ×J (♂) group. Correction analysis demonstrated highly significant correlations (P<0.01) between fertilization rate and hatch rate (0.657), and fertilization rate and survival rate (0.432). These results indicated that the crosses between different stocks might be potentially effective for genetic improvement in Japanese flounder.

Abstract:Litopenaeus vannamei was fed with basal diets respectively supplemented with 0%, 1%, 2% and 4% salt and cultured in low salinity water for 40 d. The study was conducted to investigate the histology and morphology of the shrimp reared in low salinity using light microscope and electron microscope, and also compared with the seawater shrimp. Light microscope observation showed porosity of muscle fibre in shrimps of the control and 1% treatment group, some were gathered cord, some were bent, and the gap were wide between some perimysium. But as the addition of salt increased, muscle fiber characteristics were improved, especially for the 2% and 4% treatments. Muscle fibres of shrimps in these treatments were better distributed than the other group. The ultrastructure of the shrimp under electron microscope showed irregular array of the myofilament, and incomplete in the control and 1% treatment. The distribution of myofilament in 2% treatment was relatively homogeneous, but the thin filaments had small diameter and large quantity. Some irregular filaments were arranged in clumps. But the 4% treatment was much better, and not different from seawater shrimp; the filaments all distributed uniformly and in the form of hexagonal lattice array. On longitudinal section, the sarcomere in the 1% and 2% treatments were untidy, some were twisted and overlapping; while those in the 4% treatment were well-shaped, clearly distinguishable, and the length of sarcomere were significantly greater than the other treatments (P<0.05). As the addition of dietary salt increased, myofibril diameter, solid thick filament diameter, hollow thick filament diameter, and A and H band width showed no significant difference（P>0.05）.

Abstract:This paper dealt with the embryonic and nectochaeta development of Perinereis nuntia Savigny under different conditions of temperature, salinity and diet. The results showed that: The ranges of suitable temperature and salinity for embryonic development were 18~25℃ and 25~32 respectively; The ranges of suitable temperature and salinity for nectochaeta growth were 24~32℃ and 20~35 respectively;Tenuous diet could be ingested, but the survival rate of larval feeding on microalgae was higher than that of larval feeding on egg york or yeast.

Abstract:Nutritiona1 components in muscle of Epinephelus septemfasciatus were analyzed with routine methods．The results showed that contents of crude protein, crude fat and dressed fish of fresh muscles were 19.60%, 2.70% and 76.73%, respectively．The tota1 content of amino acids was 18.33%；the content of essentia1 amino acids was 7.59%；the percentage of essentia1 amino acids in tota1 amino acids was 41.40%. The five delicious amino acids accounted for 8.22% and the amount of po1yunsa1turated fatty (PUFA ) was 32.45%．The essential amino acids index (EAAI) was 82.38. The content of EPA and DHA was 6.11% and 12.78%, respectively. It was apparent that the content of the different amino acids was stable and the corrtrition rate of the essentia1 amino acids accorded with FAO/WHO standard. The composition of mineral and trace elements of the fish was reasonable. It was indicated that E. septemfasciatus is a fish species with better nutritive value and therefore E. septemfasciatus will be an important cultured species in the future.

Abstract:Perkinsus sp. are parasites for marine bivalves. They can have severe pathogenic effect on their hosts and cause significant economic loses to the bivalve culture industry. To facilitate rapid and sensitive diagnosis of Perkinsus sp. the real time TaqMan PCR method was developed to detect Perkinsus sp. infection in oysters and other bivalves. The primers and TaqMan probe were designed and chosen to amplify the conserved internal transcript spacer 2 (ITS-2) segment of genus Perkinsus sp. ribosomal DNA. The sensitivity and specificity of the developed method were examined using the plasmid containing the targeted ITS-2 fragment as template. The online BLAST analysis showed that the primers and probe were specific enough to distinguish Perkinsus sp. from Bonamia sp. and other protistan parasites while not affected by bivalve tissue DNA at the same time. The dynamic range of the developed method was between 2.6×101and 2.6×107copies, meaning that the target DNA could be reliably detected and quantified for plasmid template DNA at a concentration as low as 26 copies. Thirty samples, collected from different sea areas of China, were tested for Perkinsus infection and 3 samples, collected from Shandong and Fujian coastal areas respectively, gave positive results. This test result was confirmed by traditional FTM culturing method. In conclusion, the real time PCR method is rapid, sensitive and specific for Perkinsus, and can be used to inspect Perkinsosis in the farm and for quarantine use. 

Abstract:There are many food quality indices, such as carbon content, fat content, protein content, P.content, C and N ratio, RNA and DNA ratio and various amino acids content etc. In this study, five food quality indices including C/N, fat content, protein content, carbon content and dry matter content of six species of forage fish were calculated and ranked with the major component analysis method. The results showed that, according to the first major component which represented energy content of the organisms, quality of the six fish species ranked from high to low was: Japanese anchovy, tapertail anchovy, scaly hairfin anchovy, madura anchovy, lined cardinalfish and bighead croaker. The second major component represented nutrition of the organisms, and the ranking of the fish, from high to low was: scaly hairfin anchovy, tapertail anchovy, bighead croaker, madura anchovy, Japanese anchovy and lined cardinalfish. The integrated major components represented food quality, by which the ranking of the six organisms was: tapertail anchovy, scaly hairfin anchovy, Japanese anchovy, madura anchovy, lined cardinalfish and bighead croaker. It is suggested that single food quality index or one sort of food index could not fully represent food quality of the organisms.

Abstract:In this experiment, the survival rate and change of physiological and biochemical indices of turbot Scophthalmus maximus which were kept alive at 3±0.1℃ were examined. The results showed that: ⑴ The survival rate after 60h was 95% without water. ⑵ The ATP contents of the muscle decrease obviously, and it was lower for fish kept in water than fish kept without water. ⑶ During the experiment, the MCV, BUN, CR and UA of the fish blood showed a trend of increase; however, the CR, UA and GLU for fish kept in water were obviously lower than those kept without water. The physiological and biochemical analysis revealed that, one of the reasons for fish mortality may be the inhibited excretion of metabolites, resulting in excessively high content of ammonia nitrogen which was harmful to the fish.

Abstract:A method for early production of large-size Sargassum thunbergii seedling in north China was developed, which consisted of procedures such as 50 d advancement of seed collection, timesaving of indoor cultivation and accelerated artificial maturation of broodstock thalli. This method should be used in combination with a set of off-shore mariculture and management techniqes. It is applicable in north China as proved by trials for three consecutive years. About 33.737 million healthy seedlings with uniform size were bred with this method, which grew into vertical young thalli (4~6 cm in length) with 3~4 branches after being cultured off shore for over three months. This method overcomes the difficulty of breeding large-size seedlings met in previous S. thunbergii seedling production practice, and will certainly facilitate the large scale seedling production and cultivation of S. thunbergii.

Abstract:The ecological environmental quality of Lüsi fishing ground of Jiangsu Province was analyzed by integrated assessment methods. The results of NQI's assessment showed that Lüsi fishing ground was at eutrophication or medium nutrition level, and A value analysis showed slight or medium organic pollution all through this fishing ground. Contents of heavy metals, including Cu, Zn and Hg were above the standard limit at some sampling sites; while contents of Pb, Cd and As were within the range of natural background value. Analyzed by integrated assessment methods, the eco environment quality of Lüsi fishing ground was relatively poor most of the time, and calls for improvement.

Abstract:The method for the determination of three nitroimidazole residues in aquatic products was developed by high performance liquid chromatography tandem mass spectrometry(HPLC-MS/MS). Deuterated dimetridazole (DMZ-D3) was added to the sample as internal standard before extraction. The sample was extracted with ethyl acetate. The mass spectrometer was operated in the positive ion mode using multiple reaction monitoring for qualitative and quantitative analysis of MTZ,DMZ and RNZ at the same time. The preliminary treatment included predigestion，and no solid phase extraction(SPE) procedure was adopted. The advantage of the method was simple operation，less organic chemicals consumed，and shorter operation time. The limits of detection for DMZ,MTZ and RNZ were 0.5 μg/kg. The limits of quantitation for DMZ、MTZ and RNZ were 1.0 μg/kg.

Abstract:Based on the survey data in Enteromorpha prolifera outbreak area of the Yellow Sea during July 9-14,2008, distribution patterns of temperature, salinity, dissolved oxygen (DO), nutrients and their relationships with green tide were studied. The results showed that DO was oversaturated for nearly all the stations, averaged 9.22 mg/L. Generally, DO showed lower values in southern area and higher values in northern area, lower in eastern area and higher in western area. Average concentration of dissolved inorganic nitrogen (DIN) was 9.07 mol/L. The DIN values in northern area were lower than in southern area, and that in offshore area were lower than in northern Jiangsu coastal area. Average concentration of phosphate was 0.19 mol/L, with a decreasing trend from the east to the west and from the open sea to the Haizhou Bay. The higher nutrient values were found in the eastern survey area. It was observed that temperature, salinity, DO, nutrient values were suitable for the growth and spore release of E.prolifera. In a large accumulation area of E.prolifera, the average concentrations of DIN (14.89 mol/L) and phosphate (0.27 mol/L) were higher than the other areas. It was indicated that adequate nutrients were the material base for green tide. Meanwhile, the average N/P ratios at the surface layer, ten meters layer and bottom layer were 702, 194 and 411, respectively, higher than the Redfield value. Most investigated waters were subjected to potential phosphorus limitation.

Abstract:The interaction between HDPE submersible deep-sea cage and wave current was analyzed by a number of in situ tests for cage submergence. The submersible cage could not sink completely because the sinking speed of the pipe cabins was different. And another important reason was the cage barycenter drift due to the water flow in the pipe cabins.The key technology of net cage sinking is controlling the sinking obliquity and eliminating block of the exhaust pipeline.

Abstract:Enteromorpha prolifera is a seaweed species that is responsible for widespread green tides. It is also a seafood species and contains relatively high levels of protein, fatty acids and trace elements. In this study, fresh E. prolifera was treated by protease, cellulase, formic acid and natural fermentation, before being used as feed for young sea cucumber Apostichopus japonicus. The protease treated E. prolifera obtained good growth in sea cucumbers. It is suggested that, after proper treatment and processing, E. prolifera may be a good feed source for sea cucumbers, and this is a feasible way to utilize this green tide species as a resource.

Abstract:Effects of light qualities (white light, red light and blue light) on the growth and rhizoid development of Laminaria japonica Aresch young sporophyte were investigated. During the culture period of 56 days, the young sporophyte cultured in blue light had a frond size of 9530±125 μm length/1 350±49 μm width, about four folds greater than that in white light; and the young sporophytes’ growth was much delayed in red light, at a size of 580±63 μm length/135±11 μm width. However, the development of rhizoid showed little difference between different light qualities. The ratios of rhizoid length to frond length were the highest in red light and lowest in blue light, which all decreased as the cultures prolonged. Fucoxanthin, one of the major light harvesting pigments in Laminaria with absorption spectrum peaking in blue light region is highly effective in capturing blue light. Consequently, the more the blue light irradiance was provided, the more the light energy was captured, resulting in the higher photosynthetic rate. Because the rhizoid is differentiated from the Laminaria frond and possesses degraded photosynthetic capacity, it was less reactive to light qualities than the frond and showed similar development under the three lights.

Abstract:Two specimens of gerreid fish were collected by trawl from Qiaogang, Beihai City, Guangxi Zhuang Autonomous Region. These two specimens were identified as Gerres macracanthusBleeker, 1854 and represented the first record from the South China Sea. It could be distinguished by a combination of the following characteristics: Body compressed, oblong in shape, its depth 2.2 to 2.3 times in standard length. Dorsal and ventral profiles of body convex, and body deepest at the beginning of dorsal fin. Mouth small, protractible, pointing downward when protracted. Body covered with deciduous cycloid scales; scales on lateral line 41 to 43. Dorsal fin with IX spines and 10 soft rays, second spine laterally compressed and reducing to a filament, reaching the base of caudal fin when depressed; anal fin with Ⅲ spines and 7 soft rays, its third spine a bit more longer than the second anal-fin spine; pectoral fins long, tip of depressed fins reaching the first anal-fin spine; caudal fin deeply forked. Body silvery, with 7 to 10 blue-grayish dusky bands on upper half of sides, more apparent in juveniles. Dorsal fin hyaline except for the end of filamentous spine, which is black; anal, pectoral, and pelvic fins yellowish; caudal fin dusky yellowish, inner margins of two lobes of caudal fin dark, outer margin of lower lobe of caudal fin white.