Abstract:PiggyBac(PB) transposon is derived from Trichoplusia ni of lepidopteran and has been widely used in transgenic and insertion mutagenesis studies in mouse. Currently, relevant research about PiggyBac transposons used in farmed fish has not yet been reported. To study insertion efficiency of PiggyBac transposon in the genome of M. amblycephala, we built pPBs-EF1α-eGFP donor plasmid with PiggyBac transposon left and right arms, EF1α promoter and eGFP gene,then co-injected with PiggyBac transposase mRNA into the 1-2 cell stage fertilized eggs of M. amblycephala. The concentrations of donor plasmid and transposase mRNA were 50 ng/μL and 100 ng/μL respectively. The eGFP fluorescence expression rate was 58.26%. In adult fish, PCR results demonstrated that integration efficiency of PiggyBac transposition system was 53.04% in M. amblycephala genome. Our data suggest that PiggyBac transposon can efficiently mediate gene insertion in M. amblycephala, which could be used in insertional mutagenesis in M. amblycephala.

Abstract:In the experiment, enterobacterial repetitive intergenic consensus (ERIC-PCR) was used to analyze the typing of the 105 strains of Aeromonas hydrophila collected from freshwater aquaculture area in Jiangsu, Henan, and Fujian. The genotyping technique was used to apply in the epidemiological investigation of the strains and evaluate the relationship of the genotype, regional distribution and the ecological niches. Electrophoresis prints was analysed by using Quantity one 4.6 and used UPGMA to make a tree plot to analyse hereditary character. 28 special genotypes were identified from the 105 isolates. Genotype ⅩⅤ was the dominant genotype, consisting of 20 strains, whereas genotypes Ⅳ, Ⅺ, ⅩⅪ, ⅩⅩⅤ, ⅩⅩⅥ, ⅩⅩⅦ and ⅩⅩⅧ contained only one strain. There is a tendency that the strains from the same geographic area or ecological niches could be clustered into one group. In addition, A. hydrophila from different regions and ecological niches might get together for the same genotype. The results suggest that there is likely some relevance between the genotype and ecological niche among A. hydrophila strains.

Abstract:The detailed descriptions of the histological observation of the brain and thoracic ganglion mass in Chinese mitten crab, Eriocheir sinensis were reported in this study. The brain was located between the bases of two eyestalks. It consisted of protocerebrum, deutocerebrum, tritocerebrum and each part of the nerve bundles. A variety of neuropiles and 12 types of cell clusters were observed in brain sections. The thoracic ganglion mass was observed as a flat disc in shape, close to the ventral central of carapace, and with a number of outgoing nerve bundles. Different types of cell clusters could also be observed. These results not only lay the foundation for the further research of neurosecretory cells in Chinese mitten crab, but also provide reference to investigate the brains and thoracic ganglion masses in other crustaceans.

Abstract:Serotonin (5-HT) exists in all kinds of animals' digestive tract, which has some important physiology effects on the growth and reproduction of crustaceans. Tryptophan hydroxylase (TPH) is the rate-limiting enzyme for 5-HT biosynthesis and can be used to identify 5-HT as a marker. The morphology and distribution of TPH in the midgut, the hindgut ampulla and hindgut of Eriocheir sinensis were mainly studied in this research by using histology and immunohistochemical technique. The result shows that: the histology of the crab intestine in midgut is similar to that in hindgut. There four layers can be identified in midgut and hindgut including the mucosa, submucosa, muscularis and adventitia. However, the size of adventitia of the hindgut ampulla composed of connective tissue is larger than that of midgut and hindgut. Except adventitia, the histology of distant rostrol and near rostrol of hindgut ampulla is similar to midgut and hindgnut respectively. TPH can be detected by immunolocalization in the midgut, the hindgut ampulla and hindgut. In the midgut, TPH is mainly distributed in the nucleus of mucosal epithelial cells. In the hindgut ampulla, TPH was widely distributed in the nucleus of mucosal epithelial cells close to the midgut and the cytoplasm of mucosal epithelial cells close to the hindgut,and peripheral connective tissue. In the hindgut, TPH is mainly found in the cytoplasm of mucosal epithelial cells. These results will be helpful for future studies on physiological regulation mechanism of 5-HT in the digestive tract of the crustaceans.

Abstract:The crustacean plankton community structure and water quality were compared between freshwater prawn (Macrobrachium rosenbergi) monoculture ponds and prawn+pearl mussel (M. rosenbergi+Hyriopsis cumingii) polyculture ponds located in Baibu Town, Haiyan County, Zhejiang Province from June to October in 2011. This study aimed at understanding the ecological effects of prawn + pearl mussel polycuture. TN, TP, NO₃-N and DO were significantly lower in polyculture ponds than those in monoculture ponds, and no differences in other parameters of water chemistry between two culturing modes were found. A total of 22 crustacean plankton species were identified, including 13 Cladoceran species and 9 Copepod species, accounting for 59.09% and 49.91% of the total species number of crustacean plankton, respectively. Significant difference between culture modes in Shannon-wiener diversity index of the crustacean plankton was found, but not detected in Pielou evenness index. Density and biomass in monoculture ponds were significantly higher than those in polyculture ponds. Stepwise regression analysis showed that water temperature and total phosphorus from 12 environmental factors were the main factors affecting density and biomass of crustacean plankton. Canonical correspondence analysis (CCA) indicated that water temperature was the key factor influencing the temporal and spatial distribution of crustacean plankton. The output of M. rosenbergii (533.30±104.24 kg/m²) was significantly lower in monoculture ponds than that in polyculture ponds (866.70±214.92 kg/m²) (P<0.01). Results suggest that prawn and pearl mussel polyculture can improve the water quality of the aquaculture ponds. Although the polyculture can't significantly change the species composition of crustacean plankton, it can significantly decrease the diversity, density and biomass of crustacean plankton. Meanwhile, prawn and mussel polyculture can also raise the output of prawn.

Abstract:Siniperca scherzeri, one of the most important economic freshwater fishes, is distributed in China widely. In recent decades, the resources of Siniperca scherzeri declined rapidly because of the deterioration of ecological enviroments and excessive catching. In order to protect and exploit it reasonably, the artificial propagation was conducted in Fujian province. The fertilized eggs were obtained by injecting interior hormone into the parent female fish and using artificial dry-fertilization, and were hatched at temperature 20 ℃. The development of embryo and larva of Siniperca scherzeri was observed consecutively. The morphological features and development characteristics of Siniperca scherzeri were described during the embryo and larva stages. The adhesive eggs were found to be about glutinous,light yellow in color,and (1.76±0.08)mm in diameter, and grew (2.20±0.09)mm 5 min after fertilization and inflation. When water temperature was 20 ℃,the hatching time was 189.33 h, and the newly hatched larvae had mean total length (5.57±0.18)mm and phototaxis. At the water temperature 24 ℃, the larvae began feeding when 3 days old and entered the mixed nutrition stage and the phototaxis disappeared. The yolk-sac exhausted when 5 days old, their oil globes were absorbed completely at the 6 days old when larvae came into the stage of nutrition outside completely. There was an extremely significant linear relationship between total length and age:y=0.4916x＋5.7209(P<0.01).

Abstract:In order to get suitable cultivating conditions, the effects of environmental factors on growth of the 60-days-old Sargassum horneri seedlings were investigated in laboratory. The results showed that, S. horneri seedlings survived at 15 to 30 ℃, and suitable temperature range was from 20 to 25 ℃. The seedlings grew up under light intensity from 500 to 7 500 LX, and the better light intensity range was from 2 500 to 4 500 LX. Seedlings could grow in the salinity range from 10 to 40, and the suitable salinity was 30. Long photoperiod (18L:6D) was more beneficial to growth of S. horneri seedlings. The low cultivation density (5-25·L^-1) was beneficial to growth and development of the seedlings. These results provided basic technical data for artificial seeding of S. horneri to spend summer indoors.

Abstract:In this study, a liquid-phase oxygen electrode system and an antioxidant enzymes kit were used to determine the photosynthetic characteristics and antioxidant system of Sargassum thunbergii at various pH and salinities. The net photosynthetic rates (P_n), pigment content, maleic dialdehyde (MDA) content and antioxidant enzymes activity of S. thunbergii were investigated. The major results included: (1) P_n rapidly decreased at pH 6.0 and pH 9.5 for 24 h, which were remarkably significant (P<0.05) compared with that of the control (pH 8.5) for 48 h. (2) Both superoxide dismutase (SOD) and catalase (CAT) activity increased significantly (P<0.05) at pH 9.5 for 48 h. And MDA content firstly increased, then decreased at pH 9.5 for 48 h. Compared with that of control (salinity 31), P_n decreased significantly (P<0.05) at salinity 15 for 24 h and at salinity 25 or salinity 20 for 48 h. However, P_n had some rise at salinity 25, 20 and 15 for 72h. (4) MDA content increased significantly (P<0.05) at first 24 h and then rapidly decreased at salinity 20. And both SOD and CAT activity increased significantly (P<0.05) at salinity 20 from 24 h to 48 h. MDA content increased significantly (P<0.05) with SOD, CAT activity relatively low at salinity 15 after 72 h. Above results indicated that photosynthetic capacity of S. thunbergii was inhibited at pH 6.0 and pH 9.5. S. thunbergii was damaged by reactive oxygen species (ROS) under strong alkaline stress. Antioxidant enzymes eliminated ROS readily at salinity over 15, but had low activity at salinity 15. In a word, these results revealed the change of photosynthetic capacity and provided reference for the regulating mechanism of antioxidant system response under adversity stress.

Abstract:This paper used Ulva compressa which is the composing species of green algae communities in Rudong seaweed farming sea area for investigation. Experiments studied the effects of sodium hypochlorite on chlorophyll composition, fluorescence characteristics and photosynthetic rate of U.compressa by chlorophyll extract, chlorophyll fluorescence technology and liquid oxygen electrode. The results showed that with the NaClO concentration increasing, the chlorophyll content and fluorescence characteristics of U.compressa were gradually decreasing. After 10.0 mmol/L NaClO treatment, Chl.a and Chl.b respectively reduced to 0.030 mg/g and 0.039 mg/g; 0.00-6.00 mmol/L NaClO have significant influence on the fluorescence characteristics of the algae; 10.0-100 μmol/L NaClO can make the photosynthetic rate of U.compressa decline significantly in 3 min, in which 100 μmol/L group declined from the control group of 1 315 nmol O₂/(min·g) to -472 nmol O₂/(min·g). According to the experiments and verification in aquaculture area, 4.0 mmol/L NaClO could be regarded as an ideal reagent in green algae removing.

Abstract:This study aimed to analyze flesh quality traits of wild and farmed Sinonovacula constricta in Sanmen Bay, including crude protein, moisture, crude fat, ash, amino acid, fatty acid, texture and colour. The results showed that moisture, crude protein, crude fat and ash had significant differences between wild and farmed Sinonovacula constricta in Sanmen Bay (P<0.05). The composition and content of amino acids in muscle had difference between wild and farmed Sinonovacula constricta. The higher amino acids contents of farmed Sinonovacula constricta arranged in the following order: glutamic acid> aspartic acid>lysine>arginine>leucine>alanine>valine>glycine; The higher amino acids content of wild Sinonovacula constricta arranged in the following order: glutamic acid> aspartic acid> alanine> leucine> lysine> arginine> glycine> valine. The components and contents of fatty acid did not have the same diversification in wild and farmed Sinonovacula constricta, but the total percentage of polyunsaturated fatty acid content in wild was higher than that of farmed Sinonovacula constricta. Texture profile analysis with different areas of wild and farmed Sinonovacula constricta was experimented, and the results showed that the adhesiveness and springiness of visceral and foot muscle of farmed better than wild Sinonovacula constricta(P<0.05). However, the colour of muscle showed no significant difference between wild and farmed Sinonovacula constricta (P>0.05). Hence, it is concluded that farmed Sinonovacula constricta show better size, dressing percentage and texture than wild Sinonovacula constricta, but lower nutritional value than wild Sinonovacula constricta in Sanmen Bay.

Abstract:In this research, the quality of water in Sansha Bay was analyzed and evaluated from May 2009 to May 2010, with 20 sampling stations, and 8 voyages. The results showed: In terms of seasonal change, the best seawater quality of Sansha Bay appeared in spring with a poor nutrient status and the tested indices were lower than the second-grade water quality criteria. The nitrogen concentration of Sansha Bay was very low in summer, while phosphate concentration was always higher than 0.045 mg/L. The quality of water in Sansha Bay in summer was at the stage of nitrogen-limited potential eutrophication. The worst seawater quality of Sansha Bay appeared in autumn. During this period, phosphate concentration in most stations were higher than 0.06 mg/L and nitrogen concentration were higher than 0.6 mg/L in some areas, which were both much higher than those in summer. Water quality of Sansha Bay in autumn was at the stage of middling nitrogen-limited potential eutrophication. Tested indices showed that the seawater quality in winter, which was similar to that of spring, fitted the third-grade water quality criteria and was at the stage of middling nutrient level. In terms of the spatial distribution, poor water quality obviously appeared in the west region of Sandu Island because of its cage culture, and better water quality obviously appeared in the east region of Sandu Island because of its laminaria culture. Downtrend of DO could be found from bay mouth to bay top. Compared with bay mouth, lower conductivity and TSP (Total Suspended Particles) were found at bay top due to runoff from inland.

Abstract:In this paper, coupling ocean and oil spill model, an oil spill trajectory forecast model for Yangtze Estuary was developed. The ocean model can better simulate the sea surface current field. Oil spill model by using oil particles tracking method of random walk and Lagrange, can quickly predict the drift trajectory and swept area of oil particles. Result shows that oil particle distribution and swept areas in spring tide are greater than those in neap tide. Spilled oil particles in the south branch would drift to south and north channels and south and north passages. The greatest harms to ecological environment will affect water intake of Chenhang and Qingchaosha reservoirs, and has potential ecological harm to the Chinese sturgeon and Jiuduansha wetland reserve; Spilled oil particles in the north branch are mainly distributed in the north branch channel and both shores. If oil spill spot is in upper north branch, oil particles would flow backward into the south branch channel, will do great harm to ecology; spilled oil particles in south channel would drift to the north and south passage, and will not harm two reservoirs and Chinese sturgeon reserve, but will do potential harm to Jiuduansha reserves; Spilled oil particles in the north channel would drift to Chongming island out sea, and diffusion range is very large, only harming the Chinese sturgeon reserve.

Abstract:As an economically important target species, anadromous Coilia nasus palys a role in both ecology and fishery in Yangtze River. According to the monitoring data collected by four study fleets in Yangtze River estuary, we analyzed the annual changes of the features and the stock status of C.nasus in the fishing season. The results indicated that there were significant differences in size distribution of C.nasus in Yangtze River estuary among the four year from 2008 to 2011. Furthermore, the mean fork length in 2011 was the smallest among these four years, and on the contrary, the dominant length in 2008 was 26-38 cm that was the greatest from 2008-2011. Moreover, the percentage of the larger C.nasus (W≥150 g) catch was dropping from 2008 to 2011 and that of the smaller C. nasus (W≤50 g) was increasing,which reflected that the miniaturization of C. nasus was evident. CPUE of C. nasus was decreasing by year in 2008-2011 and the lowest CPUE occurred in 2011 which decreased by 95.5% compared to the CPUE in 2010. The peak fishing period usually started from late March to middle April with the high yield in each year based on the catch analysis.

Abstract:In order to understand the feeding ecology of Agrammus agrammus in the rocky reef habitat off the Ma'an Archipelago Special Marine Reserves, the dietary composition and feeding strategy of Agrammus agrammus were analyzed based on the 252 fish samples collected from March, 2009 to February, 2010. The results showed that A. agrammus mainly preyed on Amphipoda (Caprellidae) and was a specialized feeder on Caprellidae. The diet of A. agrammus showed significant seasonal patterns, and was dominated by Amphipoda (Caprellidae) in spring, summer and autumn and crabs, gastropods and others in winter. Agrammus agrammus showed a specilized feeding strategy in spring, summer and autumn and genralized feeding strategy in winter.

Abstract:Cephalopods are important economic marine animals not only because of high quality animal protein they supply for people, but also an vital role they play in the marine ecosystem. It is of important significance to explore their spatial distribution patterns and evolutionary history from the molecular level as cephalopods are distributed widely in three oceans and Polar seas with a great variety of species. This paper introduced the history of molecular phylogeography briefly, and illustrated its theoretical principle and practical basis. It reviewed the research progress in molecular phylogeography, and summarized population genetic structure of cephalopods and phylogeographic patterns as well as factors that influenced them. Distribution patterns of cephalopods were also disscussed from the point of view of molecular phylogeny, and the existing shortage was put forward followed by with several prospects and analysis.

Abstract:Fisheries association, fisheries society, and fisheries cooperative, which are established and operated legally, and managed democratically, belong to fisheries intermediary organizations that have similar appearance. Through deep research from three dimensions of nature, function and registration authority, distinct differentiations can be found. Similar appearance leads to certain problems, which reflects critically on the concepts abuse and the dislocation, offside and lack of functions between fisheries society and fisheries cooperative. At the same time, a few of local governments can't master the way and strength of support among them correctly. In order to safeguard their healthy existence and orderly development space, they need further clarification in concept differentiation, function orientation, the way and strength of support carefully.

Abstract:Jumbo flying squid (Dosidicus gigas) is a kind of short life cycle species, which is widely distributed in the eastern Pacific Ocean. The abundance and distribution of D. gigas are highly subjected to the fluctuated environmental conditions from the spawning and fishing ground in different spatio-temporal scales. In this study, we use the fishing data from the Chinese squid jigging fleets to compare the habitats in the open waters of Chilean and Peruvian EEZs and the high sea in Equator by using the information gain technology (IGT), combined with the data obtained from the satellite remote sensing. The research showed that the range of suitable sea surface temperature (SST) in the central fishing ground in the open waters of Chilean and Peruvian EEZs are 15-23 ℃ and 16-25 ℃, respectively. The SST corresponding to the largest fishing frequency showed obvious seasonal variability and has a close relationship with the monthly average SST. The result of the information gain technology indicated that the key factors affecting the distribution of fishing ground of Dosidicus gigas in the open waters of Chilean and Peruvian EEZs are SST, T₅₅ and G_0-55. The environment factors affecting the fishing ground were basically the same between Chile and Peru. The study suggested that there were differences in the key environmental factors indicating fishing ground of Dosidicus gigas in different waters, which were mainly caused by different marine environment.

Abstract:Fishery energy-saving and environmental protection play an important role in promoting the development of marine economy. Compared with traditional marine power system, hybrid propulsion system has some advantages, such as, wide speed range, strong driving force, easy positive inversion, small volume, flexible layout, convenient installation and maintenance, low vibration and noise. When tuna longliner is working, the main engine is in the low speed and low load operation conditions. It will cause higher specific fuel consumption and carbon deposition. Then the back pressure of turbocharger will increase, and the surge will be caused in the end. In addition, the main engine is limited by minimum stable engine speed. Suddenly quick and slow speed is not conducive to the production. According to the methods and characteristics of tuna longliner, a kind of electromechanical hybrid propulsion system is presented in this paper. Sectional drive parallel electrical hybrid propulsion structure is used in this system. It can reduce the dependence on main engine when tuna longliner sails or works. The redundancy of propulsion system can be improved, as well as the operating flexibility. The ship maneuverability and integrated propulsion efficiency can be promoted significantly. Through the analysis of the economic and environmental protection index, compared with the conventional hybrid tuna longliner, the general fuel consumption can reduce by 20% under the same condition in shooting, cruising and reeling. Also the system reliability, safety and comprehensive propulsion efficiency are improved.

Abstract:In order to avoid continous occurrence of stealing equipments and forcibly occupying fishing grounds, it is so important to develop position indicating radio beacon system with warning function. The system integrates the fishing sonar and position indicating radio beacon as a whole by means of low power consumption data collection technology and satellite data compression technology together with the combination of audio information extraction and infrared technology. Dependent on cavitation effect of the propeller, noise of the diesel engine would be collected through the underwater microphone. In the preliminary experiment, the signal of diesel noise were collected and saved in the computer, in addition, the engine would be turned off and the underwater noise would be collected. In order to observe spectrum and bands of the noise, the signal of noise would be transformed to digital signal and analysed by fast fourier transform with software program in computer. So that the alarm hardware could be designed which depended on ARM board. In embedded systems, acoustic signals were collected and processed with micro controller, and it could indicate whether there is a diesel boats. As the system integrates satellite positioning, sonar detection, radio communication, satellite communication and anti-theft on equipments, the real time transmission and monitering of fishes information could be achieved, which greatly improves the informatization level and fishing efficiency in China's tuna detection, and promotes the high efficiency of oceanic fishery resources. Experimental results show that the common small hook propeller will radiate noise, and frequency of the sound signal is about 8.5 kHZ when it runs steady.

Abstract:On the basis of the longline survey targeting albacore tuna (Thunnus alalunga) data collected from September 2012 to November 2012 in the waters near Cook Islands, the soak time calculation models of every branch line in each operation were developed by both models of hook retrieval and the hook depth prediction model of every branch line was also developed. The hook depth data were assigned to six layers of 40 m each (40-80 m, 80-120 m,120-160 m,160-200 m,200-240 m,240-280 m). The numbers of hooks and individual of fish in the whole water bin and each depth layer were estimated. The soak time of longline gear in the whole water bin and each depth layer were estimated. The soak time of longline gear were divided into one hour interval for the quantity of hooks and the individuals of albacore tuna, respectively. The respective catch rate of albacore tuna in each hour interval was calculated. The results showed that (1) the quadratic curves could be used to fit the relationship between soak time and the catch rate of albacore tuna, the catch rate of albacore tuna showed increasing at first and then decreasing trend with the increase of soak time; (2) the catch rate of albacore tuna was the highest when soak time was 11.0～11.4 h in the 40～280 m water body and six water layers. This study suggested that (1) the soak time of each hook lasted about 10.0～12.0 h in the longline operation targeting albacore tuna for improving the fishing efficiency; (2) for the pelagic longline, the optimum soak time of the whole water bin can be used to indicate the optimum soak time of various depth layers; (3) the optimum pelagic longline soak time varies with the target species; (4) the soak time of the longline gear could be considered as the effective fishing effort. The results will be applied to improve the fishing efficiency and will be used for the references to the fishing strategy and CPUE standardization.

Abstract:Ocean energy is an important marine resource and clean energy. Its development and utilization has become necessary requirements of national development strategy. Ocean energy test site can give the grid-connection test in real sea state for ocean energy devices, this is the key link for ocean energy devices transforming from engineering prototypes into scale industrialization applications. Large-scale wave energy and tidal current energy test site construction and operation conditions are introduced in this paper and a brief comparative analysis is also given; developing status and related technologies on ocean energy power generation test site in China are also discussed. And then, this paper investigated the necessity of grid-connection test on ocean energy generation,and pointed out that the construction of ocean energy test site is a way to ensure efficient use of our ocean energy resources.

Abstract:The biochemical components of two freshwater microalgae, Oocystis solitaria and Selenastrum sp., which were cultured in the media supplemented with different ferric citrate (0, 0.0039, 0.039 and 0.39 mg/L), were studied in this paper. The results indicated that O. solitaria in medium added with 0.039 mg/L ferric citrate had the highest protein content, carbohydrate content, chlorophyll a content and carotenoid content, while Selenastrum sp. in medium with 0.39 mg/L ferric citrate had the highest protein content, carbohydrate content, chlorophyll a content and carotenoid content. Both the microalgae in media with 0.39 mg/L ferric citrate had the highest total lipid contents, which were 13.7% and 22.78% for O. solitaria and Selenastrum sp. respectively, and increased 318% and 160% of that in media without ferric citrate supplementation. 18:3n3 and 18:2n6 were the dominant fatty acids in O. solitaria and Selenastrum sp. respectively. A higher ferric citrate concentration in medium induced higher level of saturated fatty acids in both the microalgae. It is therefore suggested that compared to O. solitaria, Selenastrum sp. has stronger tolerance with high ferric ion concentration and is more suitable for production of microalgae biodiesel.

Abstract:Sea area along Fengxian District is located in the northern Hangzhou Bay,where the migratory fish such as Coilia mystus,Pampus argenteus, etc must pass through for spawning and feeding migration.Set net is the only way for fishing in this sea area,so studying on the variety of yield and yield value from a set net fishing boat is very helpful to evaluate the current fishing income on the sea along Fengxian District.As no study has been carried out investigating the variation of yield value and value per unit effort (VPUE) from set net fishing boat on the sea along Fengxian District, the methods of curve estimation and cluster analysis were applied in this study to evaluate the variation of yield value and VPUE,which may be helpful to find out the relationship among yield, yield value and VPUE from a set net fishing boat in Fengxian District(from May 2009 to October 2012).The results indicated that yield value and VPUE from set net fishing boat increased year by year,yield value and VPUE in 2009 was 205.7 thousand yuan and 44.59 yuan per net respectively,and in 2012 increased to 313.5 thousand yuan and 61.98 yuan per net respectively.Yield and VPUE had no significant correlation (P=0.501>0.05),but yield value and VPUE had significant correlation(P=0.008<0.05),and the relationship between yield value and VPUE can be expressed as following equation: y= 33.812lnx + 5.3808.In seasonal variation of VPUE,there was no significant correlation between spring and summer(P=0.093>0.05),there was also no significant correlation between spring and autumn(P=0.165>0.05),but there was significant correlation between summer and autumn(P=0.008<0.05).The research showed that it was inadvisable for fishman to pursue profits by maximizing total catch and they should increase yield and proportion of commercial fishes,which can not only increase fishing income,but also promote protection of juvenile fish and recovery of fishery resources.