Abstract:To further understand the physiological mechanism of growth of different mandarin fish, the relationship between growth rates and daily food intake, pepsin activities, relative expression of pepsinogen PGA1, PGA2, PGC in stomach of juveniles of S. chuatsi, S. scherzeri and their hybrids (S. scherzeri ♀×S. chuatsi ♂ F₁) were compared and analyzed during 30 days' experiment. Results showed that average growth weight (AGW) of three species was (1.171± 0.180) g/d of S. chuatsi, (1.019± 0.104) g/d of hybrids, (0.433± 0.078) g/d of S. scherzeri, respectively, and their growth rates ranked as S. chuatsi > F₁> S. scherzeri. Daily food intake of the three species was (6.1±0.31) g/d of S. chuatsi, (4.24±0.23) g/d of S. scherzeri and (5.26±0.33) g/d of hybrids, respectively, S. chuatsi was higher than hybrids and S. scherzeri. The maximum specific pepsin activity was found in stomach, specific pepsin of the three species was (347.8±13.3) U/g of S. chuatsi, (272.1±10.9) U/g of S. scherzeri (303.4±12.1) U/g of hybrids during later periods. Among the three species, pepsin activities ranked as S. chuatsi > F₁ >S. scherzeri. Gastric PGs mRNA expression of three species all increased during the experiment. Proportion of PGC: PGA1: PGA2 was 1.1:1.0:0.7.The highest expression level of PGs was observed in S. chuatsi, PGs expression of F₁ was slightly higher than S. scherzeri (P<0.05). Growth rate was in direct correlation with amount of food intake of the three Siniperca species, and there was a corresponding relationship between amount of food intake and digestive capacity.

Abstract:Lin-29 gene from Japanese flounder (Paralichthys olivaceus) was cloned by PCR, and its gene sequence is 1 769 bp including a 1 329 bp open reading frame (ORF) which encodes a polypeptide of 442 amino acids. The lin-29 gene was predicted encoding a zinc finger protein and was highly similar to amino acid sequence in other fishes through phylogenetic analysis. BLAST analysis indicated that the lin-29 from P. olivaceus showed an average homology of 95.25 % to Larimichthys crocea. Real-time quantitative PCR revealed that expression level of the lin-29 was the highest during gastrulation stage and in the tissue of brain. The expression of lin-29 was highly up or down-regulated by thyroid hormone (TH) at different stages while thiourea (TU) up-regulated significantly the lin-29 levels. The results showed that LIN-29 played an important role in development and metabolism of P. Olivaceus. These results provided the basic information for further study on the role of lin-29 gene in the development of P. olivaceus.

Abstract:The lipopolysaccharide-induced TNF-α factor (LITAF) gene was identified from humphead snapper (Lutjanus sanguineus) spleen using homologous cloning and RACE PCR, designated as Ls-LITAF. The full length cDNA of Ls-LITAF was 815 bp, contained an ORF of 447 bp encoding a polypeptide of 148 amino acids with predicted molecular mass of 15.7 ku. Sequence alignment showed that Ls-LITAF possessed a typical LITAF domain with a CXXC and (H)xCxxC motif, shared high similarities with other fish LITAF proteins. Phylogenetic analysis indicated that Ls-LITAF clustered closely with known fish LITAFs. Ls-LITAF was distributed in all analyzed tissues with higher expressions in gill, spleen, skin and head kidney. After Vibrio harveyi infection, the expression levels of Ls-LITAF were up-regulated significantly in spleen and head kidney. These results provided a reference to further investigate the roles of Ls-LITAF in immune response of Lutjanus sanguineus.

Abstract:Japanese eel (Anguilla japonica) is a commercially important fishery species throughout eastern Asia. The effective management of this resource necessitates accurate information on the ecology of this migratory species, much of which is currently lacking. In this study, we investigated the demographic structure and growth of catadromous Anguilla japonica from the Yangtze River Estuary, China. We captured 121 individuals from the Jingjiang reach of the Yangtze River throughout October 2012. We found that males and females differed significantly in several key characteristics. Females, which were more numerous than males with an overall sex ratio of 78:43, were significantly older (5.5±1.18 years) and larger (654.9±67.6 mm, 522.1±176.2 g) than males (5.0±1.23 years, 527.8±40.1 mm、249.8±63.7 g) and had on average faster growth rate (110.48±12.76 mm year^-1) than males (96.46±16.75 mm year^-1). Although males reached a smaller theoretical asymptotic length (918.88 mm) and mass (1432.89 g) than females (610.04 mm, 385.87 g). The sampled eels at our study site were on average younger and larger than those of other populations at other sites, suggesting that maybe this region is more suitable for the growth of A. japonica;(5)The growth difference between female and male may come from their different growth strategies.

Abstract:The morphology and innervation of the statocyst in Octopus variabilis are examined by using light microscope, scanning electron microscope(SEM), transmission electron microscope(TEM) and Synchrotron radiation. The result reveals that the statocyst tissues are paired membrane sacs suspended in cartilage cavities by surface fibers, and located respectively beneath the eyes in back of head. There are two sensory epithelia in each statocyst: the macula and the crista. A single calcium statolith is covered by a mucus layer and is only lying over the top of macula hair cells. The tips of kinocilia of the macula hair cells that protrude into the crevices among loosely arranged crystal units of the ventral bottom layer of the statolith mass. Hair cells in crista are arranged in a spiral shaped strip. It consists of nine sections and all are covered by copular. Scanning electron microscope (SEM) examinations indicate that there are only equal lengths long kinocilia in hair cells surrounded by short length of microvillia, but no stereocilia are found in statocyst. The transmission electron micrographs (TEM) confirm that the kinocilia are in 9+2 tubular structure. Our Synchrotron radiation examination results reveal that there is only one ramus of nerve from brain to innervate the macula system while there are two separated nerve rami to the crista that are branched again to innervate different target sections of the hair cell strip respectively.

Abstract:Elemental concentrations were compared in Coilia ectenes, C. ectenes taihuensis, C. mystus and C. grayii. An Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES, iCAP6300) was used to measure the concentrations of 23 chemical elements(Al, B, Cd, Co, Ca, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, S, Se, Sn, Sr, Ti and Zn). The concentrations of 10 chemical elements (B, Cd, Co, Cr, Li, Mo, Pb, Se, Sn and Ti ) were below the detection limit. All samples were analyzed by One-Way ANOVA analysis, principal components analysis (PCA), hierarchical cluster analysis(HCA) and linear discriminant analysis (LDA). Results indicated that significant difference was observed among the elements concentrations of four groups. The groups of fish could be distinguished by both PCA and HCA. Discriminant function analysis allowed correct classification rate of 100%for all 30 individuals. The analysis results of elemental concentrations features indicated that the species of genus Coilia could be distinguished effectively.

Abstract:The appearance of one-year precocious crabs is a severe problem during the first year culture of Chinese mitten crab (Eriocheir sinensis), but it is unclear for the growth and precocious trait of the offspring produced by the one-year precocious crabs. Therefore, this study was conducted to investigate and compare body weight, carapace length, carapace width, weight gain rate (WGR), specific growth rate (SGR), survival rate, precocious rate, yield, distribution of body weight and final average weight of juvenile Eriocheir sinensis from one-year precocious family and two-year normally mature family during the first year culture stage. The results showed that: (1) except for carapace length of male crabs at 215-day-old, despite of males or females, the juveniles from the one-year precocious families had significantly lower (P<0.05) body weight, carapace length, carapace width, WGR and SGR than the juveniles from the two-year normally mature families at 155-and 215-day-old; (2) there was no significant difference in survival rate and yield of two types of families. Although the precocious rate of male juveniles from one-year precocious families was slightly higher than that of two-year normally mature families, no female precocious crabs was found in one-year precocious families. Overall, the precocious rate of two-year normally mature families normal crabs families was about twice that of one-year precocious families; (3) the size distribution of body weight was normal for juveniles from the two types of families, and the highest proportions of body weight were concentrated on 3-6 g and 6-9g for both males and females despite of families; however, both male and female, two-year normally mature families had the higher proportion of large size crabs (body weight>6 g) and lower proportion of small size crabs (body weight<6 g) than the one-year precocious families. In conclusion, the growth performance of juveniles from two-year normally mature families was better than that of one-year precocious families during the first year culture, and the precocity rate was different for the two types of families. Therefore, the further study should be conducted to investigate the physiological mechanism and gender differences for the one-year precocity.

Abstract:A 45-day feeding test was conducted to investigate the effects of different kinds and levels of dietary starch on liver histology of largemouth bass (LMB) with an initial body weight (23.45±0.08) g. Eight iso-nitrogenous and iso-energetic diets were formulated with four kinds of starch (wheat starch, waxy corn starch, high-amylose corn starch, and cassava starch) at 5% and 10% levels, respectively. At the end of the feeding test, liver samples of test fish were collected. Biochemical analysis and histological observation of the liver tissues were performed. The results showed that the liver of fish, fed with all diets containing 5% starch and diet containing 10% high-amylose corn starch, was found bright red as usual, while the liver of fish, fed with the other diets with 10% starch, turned pale. Meanwhile, compared to fish with diets including 5% starch and 10% high-amylase corn starch, the hepatocyte size, hepatosomatic index, hepatic glycogen content and occurrence rates of the hepatocyte vacuolization and nuclei shifting to the cellular periphery were much higher in fish fed other 10% starch diets. It would be concluded that both dietary starch kind and its level can have a significant effect on glycogen content and tissue structure of the liver in LMB, high-amylose corn starch is more suitable than wheat starch, waxy corn starch and cassava starch, and that an inclusion level of 5% dietary starch is more suitable than of 10%.

Abstract:Transferring adult Japanese flounder (Paralichthys olivaceus) directly from salinity 30 into salinity 3 and 30, effects of abrupt low salinity stress on plasma osmolality, cortisol(COR), prolactin(PRL), growth hormone(GH) were studied after 0 h, 8 h, 1 d, 2 d, 5 d, 8 d and 14 d, and the changes of Na⁺, K⁺ and Cl^- in the plasma were also monitored. Results showed that, all plasma indicators had no significant changes between control group and 0h blank group; after transfer to salinity 3, plasma osmolality decreased in 8 h, continued to decline in 1 d, and then rose slightly in 2 d and then kept stable; the levels of Na⁺ and Cl^- showed similar changes, decreased in 8h-1d, then stabilized; K⁺ gradually increased after transferring into salinity 3, then rose to the highest level in 1 d, while in 2 d it dropped to the level that was slightly higher than control group; the concentration of COR in plasma rose to the highest value in 1 d, then declined in 2 d, significantly lower than control group; PRL level reduced firstly then elevated 2 d,and it was significantly higher than the value in 30‰ seawater. Plasma GH in experimental group decreased in 1 d and then remained the lower level. As a euryhaline fish, Japanese flounder has strong adaptability to abrupt low salinity stress,and it could increase or decrease hormones rapidly, such as COR, PRL, GH, to re-establish a new internal environment homeostasis.

Abstract:Low water temperature is one of the common enviromental stressors for fishes, but no available information could be found on the physiological response to low water termperature for Epinephelus moara. The current study was conducted to investigate the effects of low water temperature stress ( 0-7 days) on the activities of antioxidant enzymes and immune parameters in serum and liver of juvenile E moara, and three water temperatures were set at 9, 13 and 17 ℃,respectively. The result demonstrated that the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) increased with the decreasing water temperature and the increasing stress time. The total antioxidant capacities (T-AOC) and malondialdehyde (MDA) contents showed different trends in the livers of the different temperature treatments, i.e., the trends of “increasing-decreasing” were found in the livers from 9 and 13 ℃ treatments while no significant difference was found in the liver of 17 ℃ treatment. The significant differences were detected in the serum T-AOC and SOD from the beginning to the end of the experiment, and the significant decrease was found on the MDA in the serum. However, the other parameters were not related significantly to the low temperature. As for immune indices in the serum, the trends of “high-low-high” were found in lysozyme (LZM) activities and contents of immunoglobulin M (IgM), but no significant difference was found on the Ig M. In conclusion, the low water temperature stress had the significant effects on the antioxidant and immune abilities for juvenile E. moara, and the low temperature led to the increasing MDA in E. moara, which may induce the synthesis of some antioxidant in the liver.

Abstract:The Vibrio parahaemolyticus(Vp) is paid much attention to as a zoonosis pathogen at present.In order to compare the virulence and pathogenicity of seven Vp strains from different sources, we used zebrafish as the model to test median lethal dosage (LD₅₀)by acute toxicity experiment within 96h, and analyzed the data with ReeD-Muench method and Bliss method.The results suggested that the LD₅₀ tested by ReeD-Muench method of human pathogenic bacteria (ATCC17802, ATCC33847) and aquatic animal pathogens(Vp13, Vp31, Vp41, Vp57)were 6.0×10⁷, 7.4×10⁷, 3.9×10⁷, 1.6×10⁸, 1.6×10⁸, 9.3×10⁷CFU/mL, respectively and 5.0×10⁷,7.6×10⁷,3.6×10⁷,1.5×10⁸,1.6×10⁸,9.4×10⁷ CFU/mL, respectively, with Bliss method. The results showed that these two kinds of calculation methods had little difference for the LD₅₀, and the virulence of these seven different Vp strains were as follows: Vp13 > ATCC17802 > ATCC33847 > Vp57 > Vp31 > Vp41 > VpKNH1.To conclude, ReeD-Muench method and Bliss method can both be used to test Vp strains virulence.However, Bliss calculation method is more simple and accurate than the ReeD-Muench method with the development of computer technology.As a result, it is the better choice for LD₅₀.

Abstract:In this paper, the phenomenon of filamentous branches hanging and their adjustment mechanism to the high light intensity for the free-floating green tide algae (Ulva prolifera) blooming in the Yellow Sea were studied.Yearly field surveys have been carried out throughout the occurring of green tide in the Yellow Sea during the past three years (2012-2014). The results showed that free-floating green algae can be divided into two parts—— floating air-sac and filamentous branches hanging under water.The floating air-sac bleached to death due to the stress of the high solar irradiance, whereas the filamentous branches could avoid specular adversity stress to survive. In July 2014, free-floating green algae were collected in the Qingdao Sea area, the air-sac and suspending filamentous branches were taken out for the measurement of chlorophyll fluorescence parameters, buoyancy and microscopic observation of cell structure. The floated air-sac Ulva thallus was white and green, and its F_v/F_m average value was about 0.29, concentration of chlorophyll was about 0.32 mg/g, with shrinking cytoplasm most skewed or discoloration. Suspending branches showed fresh green and its F_v/F_m value was relatively higher, the average was about 0.6, and the chlorophyll concentration was 0.87 mg/g, the thallus was filled with cell contents, and only a few cells began to shrink. Air-sac and suspending branches were separately cultivated at 25 ℃under 80 μmol/(m²·s) for a second observation a week later. Air-sac formed germ cell capsule and further formed the empty cells; suspending branches grew healthily and its shrinking cytoplasm ratio decreased after being cultivated.

Abstract:Based on the investigation data of pH, total alkalinity (TA), sea surface temperature (SST), salinity (S), dissolved oxygen (DO), dissolved inorganic carbon (DIC), Chl.a, etc. during four cruises from November 2012 to August 2013, the spatial and seasonal variations of dissolved inorganic carbon system parameters and aqueous pCO₂ were investigated in a large-scale mariculture area in Yantian Harbor,Sansha Bay. And the sea-air CO₂ flux was also evaluated. The results showed that the annual concentration of DIC, HCO₃^-, CO₃^2- and CO₂ was in the range of 955-1957.08,905.08-1848.13, 10.14-124.78 and 11.48-39.78 μmol/L, respectively. There were significant differences between seasons in concentrations of DIC, HCO₃^-, CO₃^2- and CO₂ (P<0.01). The annual value of aqueous pCO₂ was in the range of 391.27-1 200.49μatm, and sea-air CO₂ flux was in the range of 0.252-6.925 μmol/ (m²·d). These demonstrated that the Yantian Harbor was the weak source of atmospheric CO₂. There was significant difference for sea-air CO₂ between different sampling sites (P<0.05), and highly significant difference between different seasons (P<0.01). The sea-air CO₂ flux was the highest in autumn and spring, and was the lowest in summer. The sea-air CO₂ flux in winter was lower than that in autumn, but there was no significant difference with that in spring. The sea-air CO₂ flux was lower in the bay mouth than that in the upstream sea area in autumn, spring and winter. Distribution of pCO₂ and sea-air CO₂ flux were mainly controlled by hydrological conditions and biological uptake in Yantian Harbor. The large-scale seaweed aquaculture is helpful diffusion of CO₂ across the sea-air interface.

Abstract:Ecological niche can be used as an indicator to symbolize the resources utilization capability of certain groups of related species and inter-species relationship, and it's essential for ecology research.A survey to determine the fishery in the Zhejiang Oufei reclamation area was conducted in May 2014. The index of relative importance (IRI) was measured to determine the dominant species of fish assemblage. The niche breadth and overlap of the dominant fish species were analyzed with the Bray-curtis similarity clustering and non-metric multidimensional scaling(MDS) analysis,and the differentiation of the niche was studied with canonical correspondence analysis(CCA),aiming to approach the community structure of fishery resources and related influencing factors in the area.The results showed that:(1)There are 12 dominant species,the main dominant species were Argyrosomus argentatus Houttuyn similar with that in 2007.(2)The niche breadth index varied from 0.31 to 2.32. Argyrosomus argentatus Houttuyn, Johnius belangerii,Pampus argenteus, Squilla orarotia,Portunus trituberculatus, Collichthys lucidus and Harpadon nehereus had large niche breadths.Niche overlaps varied from 0.01 to 0.95, Clupanodon punctatus and Lepidotrigla scaled searobins had a niche overlap value about 0.95. CCA results showed that the niche breadth and overlap of dominant species were closely related with the functional groups of species and habitat conditions, and they do not have a simple positive correlation. (3) Suspended matter had more important influence on the species spatial distribution than water temperature, salinity, pH and chlorophyll a, and the species spatial distribution was less affected by dissolved oxygen.These factors could account for 59% of the species variation.

Abstract:Understanding shrimps community structure in regional scales is vital in the study of its ecological roles to predators, especially when studied area are happened to be idea feeding and spawning grounds for commercial fishes. Based on samples collected by shrimp trawls from summer(July) and autumn(October) in 2013 to winter(march) and spring(may) in 2014 in the protected Ma'an Archipelago area, we analyzed the seasonal variations in species composition, dominance, resource density and species diversity and richness of shrimps, and discussed the contribution of dominant species to the total resource density. In all, 20 species of shrimp were collected, which belonged to 9 families under 16 genera. From summer to spring, the number of shrimp species turned out to be 12, 16, 13 and 14. Palaemon gravie, Parapenaeopsis tenella and Oratosquilla oratoria were dominant species in all year, which were the main species influencing the variation in shrimp resource density. The biomass and abundance of shrimp were greatest in summer(206.7kg/km² and 117.4×103 ind/km²), while the least in autumn (46.9kg/km² and 28.7×10³ ind/km²). The Margalef richness index(D) of shrimp was 1.12-1.55, the Shannon-Wiener diversity index(H') was 0.84-1.55, and the Pielou evenness index(J') was 0.41-0.76. Diversity indinces tend to be highest in autumn, and then was in winter and summer, but lowest in spring. One-way ANOVA declared that diversity indinces had notable difference between seasons (P<0.05).

Abstract:Voyage statistics is often required in fishery management, fishing benefit calculation and resource surveys. It is used as an important reference value. Vessel monitoring system based on Beidou provides a fast and convenient means for obtaining voyage. More than fifty thousand fishing vessels had installed the terminal unit of the Beidou satellite positioning system since the Ministry of Agriculture of China started to construct fishing vessels monitoring system in Nansha Islands in 2006. The data sent by the terminal unit have a temporal resolution by 3 minutes, and a spatial resolution by 10 meters. Thus, after carrying out these fishing services for nine years, the system has recorded billions of historical cruising data for each vessel, including the time, position, speed, direction, rate of turn, etc. During the fishing operation, a complete voyage includes sailing, marine operations, and return. The ports of fishing boats sailing and return are often different. A surface was formed by the buffered land and islands with ports. Offshore distance is between ship's position and the surface. Fishing voyage is determined by the change of distance offshore. Voyages are extracted by programming. The results of six research ship voyages were compared with 43 cruises actually recorded. The difference proportion within two days of the start voyage was 95.1%. The difference proportion within two days of the end voyage was 95.2%. It can provide a more accurate reference for fisheries analysis.

Abstract:Based on the monthly Satellite remote sensing Sea Surface Temperature (SST) from 2002 to 2013, Empirical Orthogonal Function (EOF) analysis was accomplished to analyze the temporal and spatial characteristics of upwelling over Zhoushan Coastal region. The effect of wind on upwelling was analyzed by using sea surface wind field data. The result showed that first two modal variance contribution rates are 71.66% and 16.55% in July, 87.03% and 7.3% in August respectively, all of which pass the North test. The Zhoushan coastal upwelling displayed inter-annual variability and had a negative relationship to the meridional wind. The prevailing southeast wind in summer was conductive to development of the upwelling. According to the calculation of Ekman Volume transport, the order of mean velocity of upwelling in Zhoushan coastal region are respectively 3.0×10^-5 m/s and 1.5×10^-5 m/s in July and August. The upwelling in August was significantly weaker than in July, which was relevant with a significant low SST anomaly observed in August.

Abstract:According to the latest fishermen income statistics system stipulated by China National Bureau of Statistics, this paper analyzes the changes about fishermen's income structure between 2008-2013 in China. Through comprehensive computation model of grey incidence degree, we analysed the correlation degree about fishermen's income structure and fishermen's income in view of the rate differences and the absolute differences. We found the fishermen's family management income has the highest relevancy degree with fishermen's income. Based on the rate differences, the relevancy degree of fisehermen's property income is at the second place. Based on the absolute differences, the relevancy degree of fisheermen's wage income is at the second place. Through the analysis of the contribution rate and the traction from every part of Chinese fishermen's total income. We found that the contribution rate and traction offered by other household income to household business operation income are higher than that offered by fishery production income. It shows that the labour force of fishermen has obviously differentiated. The productive subsidy becomes the second element which affects fishermen income. The productive subsidy has the second relevancy degree with fishermen's income, the contribution rate and traction to fishermen's income. The traction of fishermen's wage income mainly came from the other industries, it means the low level of fishery employment and the low level of fishery industry wage. Fisheremen's rent of land-use right has the obvious negative impact to the increase of fishermen's property income, the cutting of fishing grounds restricts fishermen to increase their income.