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  • 2018 Volume 45 Issue 5
    Published: 20 October 2018
      
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  • Connotation and characteristics of deep blue fishery
    LIU Huang, XU Hao, XU Yanfei
    2018, 45(5): 1.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    As a promising new industry, deep blue fishery is the main way to solve the pressing problems of declining inshore fishery resources, insufficient space for aquaculture, low-quality aquatic products and urgent needs for superior animal protein. It has developed rapidly in recent years. But currently the concept and connotation of deep blue fishery is not clear at home and abroad. To further clarify the concept, connotation and characteristics of deep blue fishery, the paper summarizes the background and progress of deep blue fishery at home and abroad, puts forward the concept and connotation of deep blue fishery based on our country’ actual development, clarifies the fact that the deep blue fishery is an organic integrity consisting of sustainable fishing fishery, offshore industrialized green mariculture, high-value aquatic product processing, maritime cold chain logistics and information guarantee services, and expounds the industrial characteristics of the deep blue fishery including whole industry chain integration, high intensity of capital and technology, high risk, high investment and high return and so on, thus laying a theoretical foundation for promoting the construction of deep blue fishery.
  • Research progress of aquaculture wastewater treatment with aerobic denitrification technology
    HUANG Zhitao, JIANG Yuli, SONG Xiefa
    2018, 45(5): 7.
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    The arising of aerobic denitrification has made up for the deficiency of traditional biological denitrification. The research progress of aerobic denitrification technology and its application in aquaculture wastewater treatment are reviewed in this paper. The mechanism of action of aerobic denitrifying bacteria is reviewed from three aspects: microenvironment, biochemistry and enzyme system. The effects of environmental factors such as carbon source, dissolved oxygen and carbon-nitrogen ratio on the efficiency of aerobic denitrification are summarized. The application of aerobic denitrification technology such as aerobic denitrifying reactor, immobilized bacteria and external carbon source in aquaculture wastewater treatment is summarized. The advantages of aerobic denitrification in nitrate nitrogen removal and nitrogen regulation on the whole are highlighted. Aerobic denitrification technology has obvious advantages in aquaculture wastewater treatment, and it is an effective way to treat aquaculture wastewater. There are many problems in practical application, for which the technology needs further study.
  • Study on hydrodynamic characteristics of float-type net enclosure
    CUI Yong, GUAN Changtao, HUANG Bin, JIA Yudong
    2018, 45(5): 14.
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    The offshore net enclosure is usually located in open sea and affected by the wave and current obviously. It is necessary to carry out study on hydrodynamic characteristics for the safety of the net enclosure. Herein, a kind of float-type net enclosure is chosen to analyze the resistance characteristics of net enclosure through towing tank experiment. A numerical model of the net enclosure structure in wave is developed based on the finite element method, and then the maximum displacement of the float and the tension of net are studied through computer simulation. The results show that the resistance of the net enclosure increases with the velocity of flow. There is a power function relationship between resistance and velocity. The maximum resistance is 196 kN. The displacement of the float at the midpoint of head line is the maximum when the float-type net enclosure is under wave. The maximum displacement is 80mm. Furthermore, the tension of the net at the points where the net connects with the mooring line and the lower four corners is greater. It is suggested to increase the buoyancy of net at incident flow side to maintain the shape of the net enclosure under high speed flow. Moreover, the net where the mooring line connects with the lower four corners should be reinforced in the production of actual net.
  • Effects of plant density on water quality and growth of fish and vegetables
    CAI Shufang, CHEN Yongkuai, CHEN Min, BAO Xingsheng, ZHANG Zhong, LEI Jingui
    2018, 45(5): 19.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to evaluate the effects of different plant densities on water quality and growth of fish and vegetables in aquaponics system, an aquaponics experiment was conducted in 2017. The effective volume of water for Carassius auratus gibelio breeding was 350 L, and the breeding density was 10 kg/m3. The cultivated area of Ipomoea aquatica was 1.0m2, and the density was 60, 45 and 30 plants /m2. The results showed that when the water temperature was 29.37 - 31.40 ℃, the dissolved oxygen was 2.33 ~ 5.00 mg/L, pH was 6.22 ~ 7.42 and EC was 0.19 ~ 0.66 mS/cm, the water quality could basically meet the demand for growth of fish and vegetables. The mass concentration of system ammonia nitrogen, nitrite nitrogen and nitrate nitrogen changed significantly with time (P=0.000), the mass concentration of nitrate nitrogen in different treatment was significantly different (P=0.028), and the average mass concentration of nitrate nitrogen in the system with density of 45 plants /m2 was the highest. The experiment lasted for 33d, during which the total fresh weight of fish increased by (1.70±4.36) kg, (1.50 ± 1.57) kg, (1.67 ± 6.01) kg, and the total fresh weight of vegetables increased by (7.71 ± 2.27) kg, (6.15 ± 5.49) kg, (4.04 ± 3.01) kg. The effect of plant density on the relative growth rate of nitrogen content in the aboveground part was significant (P=0.037), and the relative growth rate of nitrogen content in the aboveground part in the system with density of 45 plants /m2 was positive. Studies have shown that fish and vegetables in the systems with three plant densities grew well, the system with density of 45 plants /m2 had higher nitrogen conversion efficiency, and the nitrogen conversion of the system and more economic output could be promoted by expanding the cultivated area of plants.
  • Effect of Nano-TiO2 coating on water purification of recirculating aquaculture system
    YANG Jing, GUAN Chongwu, SONG Hongqiao
    2018, 45(5): 26.
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    The nano-TiO2 coating was applied to the surface of the fish pond to construct a recirculating aquaculture system consisiting of test group and control group. The effect of nano-TiO2 coating on purification of the wastewater in the water circulation treatment mode was studied. The influences of mass concentration of ammonia nitrogen in the raw water C0, DO and pH value on ammonia nitrogen degradation effiency were investigated. The results showed that after 48h treatment by test group of the recirculating aquaculture system with pH 7.0-7.8, TAN 14.2-15.3 mg/L, NO3--N 20.8-21.9mg/L and colonies number > 106/mL, ammonia nitrogen degradation reaction kinetics accordedwith the first-order kinetic equation. The reaction rate constant was 0.0697h-1, the half-life was 9.92h, and the ammonia nitrogen degradation and bacteriostatic effect were good. The order of the extent of influences of mass concentration of ammonia nitrogen in the raw water C0, DO and pH on ammonia nitrogen degradation in the test group was C0> DO>pH. When the mass concentration of ammonia nitrogen in the raw water C0 was 15 mg/L, DO was 6 mg/L and pH was 7.5, the ammonia nitrogen removal rate reached 41.9% when the test group of the recirculating aquaculture system was operated for 8h. The nano-TiO2 coating applied to the surface of the fish pond has a good purifying effect on the water body of the recirculating aquaculture system, and has a broad application prospect.
  • Study on industrialized breeding of Ictalurus punctatus in Ningxia
    WANG Yuanji1, SAI Qingyun2, LI Yongjun2, WANG Yan2
    2018, 45(5): 31.
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    In order to explore the suitable conditions for artificial breeding technology of Ictalurus punctatus in Ningxia, specific to technical requirements for artificial breeding and seed rearing, some experiments, for example, effects of different oxytocin combinations and artificial parent fish combinations on reproduction rate, hatching temperature on hatching rate of fertilized eggs and seed rearing experiment in that year of Ictalurus punctatus were carried out. The result showed that the use of oxytocic drugs enabled the Ictalurus punctatus to spawn in relatively concentrated time when the water temperature was 23.5℃, and the combination of drugs was better than the use of a single drug to spawn, but the effect was not obvious. Compared with natural spawning in ponds, artificial spawning could increase the spawning rate of parent fish, the optimum incubation temperature for fertilized eggs was 24℃~26℃, and the suitable spawning temperature was 23℃~27℃. Seed rearing experiment showed that the one-year-old seed grew fast, and from larva to one-year-old seed, the optimum stocking density of the Ictalurus punctatus was 375 000- 450 000 fishes/hm2 in Ningxia.
  • Analysis and evaluation of nutritional components in the muscle of 5 strains of Penaeus vannamei cultured in circulating water in ponds#br#
    MA Lin1, JIANG Jufeng1, WU Huimin1, BAI Xiaohui1, LIU Xiaolian1, CAI Chao1, XUE Yangyang2, ZHANG zhenguo1, LI Chunyan1
    2018, 45(5): 31.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to study nutritional characteristics of 5 strains of Penaeus vannamei under culture conditions of circulating water system in ponds, nutritional components in the muscle were determined with conventional method for determination of biochemical component, analyzed and evaluated. The results showed that the flesh content of Penaeus vannamei ranged from 50.57% to56.13%. In normal nutritional components, Strain A contained the most protein (20.27%), fat (0.57%) and ash content (1.32%). The essential amino acid (EAA)/total amino acid (TAA) for the muscle of 5 strains of Penaeus vannamei was about 35%, and the structure conformed to the standard requirement of FAO/WHO. The essential amino acid index (EAAI) from high to low was Strain A (71.54%), Strain E (71.10%), Strain D (70.00%), Strain C (69.31%) and Strain B (69.17%). A total of 16 fatty acids were identified in the muscle, and there were differences in the types and contents of fatty acids in each strain. Monounsaturated fatty acids (ΣMUFA), polyunsaturated fatty acids (ΣPUFA) and EPA+DHA were the highest in Strain B and lowest in Strain C. For microelement, the iron (7.62 mg/kg) and copper (4.05 mg/kg) contents of Strain D were the highest; the highest selenium content (0.24mg/kg) was found in Strain E. It was indicated that the 5 strains cultured in circulating water in ponds all belonged to high protein and low fat food, and had balanced amino acid composition, abundant microelements and high nutritional values, where A and Strain C respectively had the highest and lowest nutritional value.
  • Study on operation effect of recirculating aquaculture system based on constructed wetland
    CHENG Guofeng1, LU Shimin1, LIU Xingguo1, ZENG Xianlei2, GU Zhaojun2
    2018, 45(5): 45.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to explore for establishment of a viable recirculating aquaculture mode, a recirculating aquaculture system reasonably combining culture pond with subsurface flow constructed wetland was designed with Carassius auratus as cultured species. The conditions of fish growth and water quality were analyzed during the culture period. The results showed that, after 68d of culture, the stocking density of fishes in the 4 culture ponds (A, B, C, D) increased to 2.8, 5.1, 10.3 and 20 kg/m⊃3; respectively from initially 2, 4, 8 and 16 kg/m3, and the average survival rate was (95.30±3.28)%, which realized recirculating aquaculture based on wetland. The result of water quality monitoring showed that total nitrogen (TN), total ammonia nitrogen (TAN), nitrite nitrogen (NO2-N), chemical oxygen demand (COD) and total suspended solids (TSS) removed by the wetland were respectively (35.6±7.6)%, (61.2±9.3)%, (76.5±11.5)%, (58.3±7.5)% and (88.0±3.7)%; during the culture period, the average value of TAN, NO2--N and COD was respectively (0.29±0.10), (0.075±0.023) and (11.17±2.37) mg/L; the average value of DO and TSS in the culture pond was respectively (6.84±0.92) mg/L and (64.11±17.89) mg/L. This study showed that the recirculating aquaculture system based on constructed wetland has such advantages as high survival rate, good growth and remarkable water saving and emission reduction effect.  
  • Application of low field NMR technology to screening of protective agents of freeze-dried fish vaccines
    CHEN Hui 1,2,3, CHEN Sijin 2,3, HONG Bihong 2,3, PENG Hui 1, HONG Zhuan 2,3, YI Ruizao2,3
    2018, 45(5): 51.
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    To screen protective agents suitable for freeze-dried fish vaccines, low-field nuclear magnetic resonance (LF-NMR) was applied to analyze the water distribution and mobility in different protective agents after freeze drying. According to the relaxation time of hydrogen protons, resident water can be divided into three states: bound water, immobilized water and free water. Results showed that secondary drying temperature had a great impact on the water distribution in mannitol and sucrose, and with the increase of temperature from 4℃ to 37℃, most free water desorbed and some shifted to bound water. When placed in environment with relative humidity of 43% and temperature of 25℃, most protective agents absorbed water and immobilized it to bound water, except that some bound water in mannitol shifted to free water which desorbed to the environment. Water distribution and mobility in different freeze-drying protective agents were not the same, which indicated their different ability in water binding. This research would be helpful for screening of protective agents of freeze-dried fish vaccines and optimization of freeze-drying process, to form a more stable vaccine product.
  • Experimental study on process parameters of Antarctic krill sheller
    ZHANG Junwen, ZHENG Xiaowei, OUYANG Jie, SHEN Jian
    2018, 45(5): 57.
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    In order to improve the utilization value of Antarctic krill, with self-designed Antarctic krill sheller taken as the object of study, ship loading experiment was carried out for the key components and process parameters such as the roller length, roller clearance and feed rate; sensory evaluation and yield determination were carried out for the shelled Antarctic krill to determine the optimal combination of roller clearance, roller length, feed rate and krill storage period. The results showed that when the roller length was 1.0m (A2), the roller clearance was 1.0mm (B2), the feed rate was 125 kg/h (C3) and the storage period was 15min (D1), the experimental indicators were the best; when the combination of A2B2C3D1 was used in actual production, the yield of Antarctic krill reached 24%. The study showed that the equipment could improve the shelling efficiency of Antarctic krill, and improve the level of automation during high-value processing of Antarctic krill, thus promoting the industrialization process of Antarctic krill.
  • Design and test of solar - thermal coupled drying system for kelp
    ZHU Ye, JIANG Tao, HONG Yang, CHEN Chao, ZOU Haisheng, XING Jingzhu
    2018, 45(5): 63.
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    In order to reduce the energy consumption of kelp drying, improve the drying quality and the efficiency of the drying system, modeling and research were carried out based on thermodynamics and heat transfer theory, and solar-thermal coupled drying system for kelp with sunlight greenhouse as the main body, air heat pump and heat collecting plate as heat source was designed. Drying temperature and time were set through the touch screen for kelp drying,  temperature sensor, humidity sensor and light sensor were used for measurement, and data was recorded for analysis. The drying system could recover the residual heat discharged during the drying process, dehumidify the residual heat, and then repeatedly use the heat; the solar thermal collector stored the heat energy in the water tank for secondary drying to save energy. The results showed that when the maximum air temperature was 27.5 ℃, the moisture content was about 90%, the weight of fresh kelp was 60.32 kg and the drying time was 10 h, the new kelp drying system had a good effect if the moisture content of dry kelp was 14.5 %, the weight of dry kelp was 6.9 kg and the lowest quantity of electricity was 3.91 (kW·h) / kg. The research has provided a new technical method for the large algae drying, and the technology is suitable for promotion in large algae drying of medium and large enterprises.
  • Design of automatic drafting and hanging kelp harvesting vessel
    TAN Yongming1,2, CHEN Zhixin2,3, CHU Shupo2, LOU Shangyou1, JIANG Tao3
    2018, 45(5): 69.
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    In order to solve the problem of low mechanization, high labor intensity, poor working environment and backwardness of kelp industry in China's kelp harvesting, and to resolve the contradiction between large labor consumption for kelp harvesting and difficulties in employment due to aging of labor force, planning and design are carried out from the comprehensive efficiency of the whole production process including kelp harvesting and subsequent machining, so as to optimize the production process of kelp. In view of the current traditional kelp harvesting process and specific to main problems and difficulties encountered by kelp equipment during harvesting, the environmental factors and solutions for the problems encountered in the equipment use are discussed. On the basis of solving the problems existing in the current harvesting equipment, design scheme of the key equipment of kelp harvesting – automatic drafting and hanging kelp harvesting vessel - is put forward, and the main components of the harvesting vessel and the realization of its function are introduced. It is of great significance to the mechanization of kelp industry.
  • Ultrasonic biotelemetry and its application to modern fishery
    LIU Jing1,2, TANG Yong1, XING Binbin1, YIN Leiming1, ZHUANG Xin1,2, BI Fuyang1, ZHANG Guosheng1
    2018, 45(5): 75.
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    Ultrasonic biotelemetry is a kind of acoustic telemetry technology which uses acoustic transmitters to mark and track aquatic organisms. Since its first application in 1956, it has been widely used in telemetering many aquatic animals in oceans, rivers, estuaries, lakes and reservoirs. It is the most effective method to study the behavior characteristics of aquatic animals in natural waters. However, the research of this technology in China is relatively few. Related papers of this research field are analyzed, comprehensively summarized and discussed. The research progress at home and abroad and the system composition of ultrasonic biotelemetry are summarized. This paper summarizes the classification of methods, working principle, differences between and application conditions of different ultrasonic biotelemetry, and analyzes the application prospect and problems of the technology in modern domestic fishery, providing some reference for the application of the technology in China.