10 December 2023, Volume 45 Issue 6

    

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• Research Papers
• Comparative study of three kinds of sea wind field data for the wind energy utilization in the China adjacent sea

  LIN Yifan, LIU Yufei, WANG Xiaohe, LU Peng, YANG Zihao, DONG Sheng

  2023, 45(6): 1-11. https://doi.org/10.13984/j.cnki.cn37-1141.2023.06.001

  Abstract ( ) PDF ( )

  CCMPv2, ERA5 and CFSR&CFSv2 are widely used in numerical simulation of wave and tide for their higher resolution in spatial and temporal, however the quality of the reanalysis wind field data is not constant in space. For the China Sea, due to the limited number of measured data, yet no scholar conducts extensive and detailed comparison of wind field data quality within the scope. In this paper, we extract ICOADS measured data from 1998 to 2014 and correct them to 10 meters height uniformly by utilizing anemometer height. Afterwards, the qualities of the three kinds of wind field data are compared firstly from the angle of wind speed and direction within China sea and different sea areas of it, the results show that: (1) The reanalysis wind speed and direction data from CFSR&CFSv2 and CCMPv2 respectively are consistent with measured data best in China Sea; (2) The optimal wind speed and direction data in the specific sea area mostly do not appear in the same wind field. From the angle of wind speed, ERA5 is optimal in area around the Sanba strait, the western Pacific and the northern Part of the South China Sea, and the optimal wind field in other sea areas is CFSR&CFSv2. From the angle of wind direction, CFSR&CFSv2 is optimal for the Bohai Sea, sea area around Fujian and Taiwan and Beibu Gulf respectively, and the optimal wind field in other sea areas is CCMPv2.
• Morphological change of Jiaozhou Bay from 1985 to 2020 and its driving factors as were revealed with GEE

  ZHAO Shiqi, XU Yandong, CHEN Jianqiang, WEI Xiao, WANG Yuzhen

  2023, 45(6): 12-18. https://doi.org/10.13984/j.cnki.cn37-1141.2023.06.002

  Abstract ( ) PDF ( )

  The coastal area of Jiaozhou Bay (JZB) is occupied by the heaviest population and the most developed economy of Qingdao. It is of great significance to analyze the morphological change of the coastal marine environment protection and maintain the regional sustainable development. In this paper, we retrieved Landsat series remote sensing images from the cloud platform of Google Earth Engine (GEE), extracted the spatial information of gulf shoreline from 1985 to 2020, 5 years each, automatically and comprehensively with maximum inter-class variance method, mathematical morphological method processing and Canny edge detection. The temporal and spatial variation process of JZB in 35 years was quantitatively analyzed from three dimensions, point, line and plane, and its driving factors were discussed. The results showed that the automatic interpretation of remote sensing images on GEE cloud platform can improve the extraction efficiency of gulf shoreline spatial information. From 1985 to 2020, the average direction of the center of gravity displacement of JZB was 7.61° north to east. The south bank of the bay expanded to the sea much more than the north bank did, and the west bank expanded to the sea slightly more than the east bank did. In the studying period, the length of shoreline, fractal dimension and bay morphological development index all maximized in 1990, and the shoreline length increased first, and rapidly decreased, slightly increased and slowly decreased then. In the studying period, the development and utilization degree index of shoreline have been increasing, and the bay area decreased by 17.31% (70.34 km²). The main driving factors of the bay morphological change were reclamation activities including inshore breeding ponds, port projects, urban construction, coastal communication line construction among others.
• Dynamic tests of long-term deformation of MICP cemented calcareous sand

  ZHANG Lei, YANG Junjie, WANG Ziyu

  2023, 45(6): 19-26. https://doi.org/10.13984/j.cnki.cn37-1141.2023.06.003

  Abstract ( ) PDF ( )

  The Microbially-induced calcite precipitation (MICP) method was used to test the calcareous sand collected from an island of South China Sea. A series of long-term dynamic triaxial tests of cemented samples were carried out to investigate the evolution of accumulated axial strain under different cyclic loading and nutrient concentrations. The experiments results indicated that the capability of the resisting deformation of MICP cemented calcareous sand are improved, and the increase of nutrients can improve the ability of MCP cemented calcareous sand to resist deformation. The accumulated axial strain of MICP cemented calcareous sand showed a hyperbolic relationship with the cyclic vibration number. The accumulated axial strain increased rapidly at the early stage of loading. With the loading progresses, the growth rate of the accumulated axial strain gradually slowed down and the accumulated axial strain eventually tended to be stable. On this basis, the cyclic stress ratio was introduced to establish the permanent deformation prediction formula of MICP cemented coral sand under cyclic loading, which was of positive effects on predicting the long-tern deformation of MICP cemented coral sand under cyclic loading.
• Shear deformation characteristics of sand in South China Sea revealed with digital image measurement system

  DU Qizhi, ZHANG Hong, CHENG Sheng, SHAN Hongxian

  2023, 45(6): 27-33. https://doi.org/10.13984/j.cnki.cn37-1141.2023.06.004

  Abstract ( ) PDF ( )

  The digital image measurement technology is used to carry out the conventional triaxial test to obtain the deformation information each point of the sample surface during triaxial test, and analyze the shear deformation characteristics of samples. In this study, consolidation and drainage shear tests with different confining pressures and initial relative compactness were carried out on the soil from Shen Hu area in the South China Sea. The law of shear strength variation of sand was studied, and the law of shear deformation and failure of sand samples was emphatically discussed based on the digital image measurement system. The results showed that the sand in the South China Sea has different strain softening characteristics at different confining pressures and compactness. The failure types of the samples were all "single-type". The shear band began to form at about 1/2 of the peak shear strength, and formed completely at the strain softening stage. The measured inclination of the shear band varied between 53.5° and 56.5°, which was between the inclinations of the shear band calculated by Mohr-Coulomb and Roscoe theories, and Arthur criterion can better predict the inclination of the shear band.
• Geographically weighted regression residual Kriging method applicable for the spatial prediction of sediment grain size compositions

  SUN Sijia, LIU Fucheng, ZHOU Yi, LI Rong

  2023, 45(6): 34-42. https://doi.org/10.13984/j.cnki.cn37-1141.2023.06.005

  Abstract ( ) PDF ( )

  In view of characteristics of autocorrelation and environmental correlation of the spatial distribution of grain size components in offshore surface sediments, a geographically weighted regression residual Kriging (GWRRK) method is proposed with its application feasibility analyzed and evaluated in spatial prediction of grain size compositions and sediment types using the grain size composition data of surface sediment in Haizhou Bay, north Jiangsu Province. The results showed that GWRRK method can obtain a higher spatial prediction accuracy of sediment grain size components and mapping accuracy of sediment types than the ordinary Kriging method. The overall predictive mapping accuracy of sediment types by GWRRK method reached 89.6%. Its corresponding Kappa coefficient is 0.873, indicating that the mapping types of sediments are in good agreement with their actual types. As the new method can comprehensively consider the spatial autocorrelation and environmental correlation of variables, it has practical value in quantitative spatial prediction of sediment particle size components and mapping of sediment types.
• Studies on factors affecting the bearing performance of high-pile wharf

  LYU Peng, YAN Zhen, DONG Sheng

  2023, 45(6): 43-50. https://doi.org/10.13984/j.cnki.cn37-1141.2023.06.006

  Abstract ( ) PDF ( )

  In addition to the influence of structure and material on the bearing performance of high-piled wharf, the strength of soil and the friction between pile and soil also have important influences on such performance. In the study, a three-dimensional finite element model of a high-piled wharf was established based on ABAQUS and compared with the testing results. The numerical simulation showed a good agreement with those revealed by the physical experiments. On this basis, the influences of soil strength, elastic modulus and pile-soil friction coefficient on the structural bearing performance were analyzed. The results showed that both soil strength and elastic modulus have a certain effect on the ultimate bearing capacity of the structure. Under the same horizontal load, the greater the soil strength and elastic modulus, the smaller the horizontal displacement of the structure and the smaller the bending moment. The soil strength has little effect on the maximum negative bending distance. The maximum difference appeared at 1/4 from the bottom of the pile. The elastic modulus affected both the maximum positive and negative bending moments, and the maximum bending moment change was 10%~15%. The pile-soil friction coefficient also had a certain influence on the bearing performance of the structure. Within a certain range, with the increase of μ, the ultimate bearing capacity of the structure increased gradually, and its variation range increased gradually also. However, the influence of the friction coefficient on the bending moment was mainly concentrated at the negative bending moment, and had little effect on the part affected by the positive bending moment.
• Studies on voltage stabilization strategy of underwater power transfer system with multiple receivers

  FANG Junfeng, LI Xingfei, LI Hongyu, XU Jiayi, XIE Ziming

  2023, 45(6): 51-59. https://doi.org/10.13984/j.cnki.cn37-1141.2023.06.007

  Abstract ( ) PDF ( )

  Inductive coupled power transmission technology (ICPT) has been widely applied in the power supply system of underwater equipment due to its advantages in reliability and security. To avoid the obvious fluctuation of the output voltage of ICPT system with multi-receivers with the working distance and the secondary quantity changes, we proposed a primary-side control strategy based on the active disturbance rejection controller (ADRC). By capturing the primary-side current as feedback, the strategy can maintain a constant voltage output without any communication module or voltage stabilizing module. The hardware circuit and control flow of the power transfer system was designed, respectively, by establishing the circuit model of multi-receivers ICPT system. The simulation based on Matlab/Simulink & Maxwell and the experiment of third-receivers ICPT system provided the rationality and validity of the above theory. At the same time, experiment result proved that the control strategy has better robust performance and dynamic characteristics compared with other methods.
• A comparative study on element concentrations in blood cells and plasma of three Schizothoracine species

  HOU Weiwei, WU Zhichao, JIANG Shouwen, LIN Feng, XU Qianghua

  2023, 45(6): 60-65. https://doi.org/10.13984/j.cnki.cn37-1141.2023.06.008

  Abstract ( ) PDF ( )

  To explore the mechanism underlining the adaptation of Schizothoracine species to the plateau hypoxia, we measured and compared the concentrations of 11 elements of the blood cells and plasma of two Schizothoracine fish species inhabiting high altitude, Gymnocypris scleracanthus (4 580 m) and Oxygymnocypris stewartia (3 650 m) and one inhabiting low altitude, Schizothorax prenanti (650 m), with inductively coupled plasma mass spectrometry (ICP-MS) method. In blood cells, elements Cr, Mg and Cu were different in concentration among three fish species. In the plasma, elements K and P of fish species inhabiting low altitude (S. prenanti) were significantly higher than those of two species inhabiting high altitude, and element Na of S. prenanti was significantly lower than that of fish species inhabiting high altitude. To adapt the low temperature and hypoxia at high altitude, Schizothoracine may have adjusted their body metabolism by regulating the content of elements in their body. Our findings provided a new insight into the plateau hypoxia adaptation of Schizothoracine fish species.
• Characterization of volatile substances of different product formats of Chinese mitten crab (Eriocheir sinensis)

  YIN Jing, GUAN Weibin, SHI Wei, WANG Jianglong, YU Xiaoyan, ZHANG Guangdi

  2023, 45(6): 66-74. https://doi.org/10.13984/j.cnki.cn37-1141.2023.06.009

  Abstract ( ) PDF ( )

  Based on the visual characteristics demonstrated in the headspace-gas chromatography-ion mobility spectroscopy (HS-GC-IMS), the volatile substances of the muscle and gonad of Chinese mitten crab were determined for the fresh, the refrigerated and anesthetized, and the frozen products of the crab harvested from rice crab symbiotic system. The differences in the contents of these materials were revealed according to the fingerprints in the spectra through principal component analysis and with the matching matrices method. In total, 47 volatile substances were identified among three formats of products. The main volatile substances included ketones, aldehydes, alcohols, acids, esters and heterocyclic, of them the most important were 12 ketones, 9 aldehydes and 8 alcohols. In the muscles of fresh, refrigerated and anesthetized, and frozen products, 15, 19 and 22 volatile substances were identified. In the Chinese mitten crab gonad in different product formats, 17, 19 and 32 volatile substances were found, and some of them were shared among the product formats. The volatile substances (ketones, alcohols, aldehydes) increased with freezing. From the fresh to the anaesthetized to the frozen, a large number of aldehydes, furans, pyrazines among others produced in gonads and muscles, of these substances, 2-pentylfuran causes the quality decrease of Chinese mitten crab. The volatile substance variation and PCA of three formats of products can clearly distinguish the three formats. Our findings provides a reference for volatile substance evaluation, product format identification, deep processing, preservation and cold chain circulation of Chinese mitten crab.
• Study on microbial diversity in Daihai lake, Inner Mongolia

  XU Chaoqun, XUE Junzeng, WANG Qiong, WU Huixian

  2023, 45(6): 75-82. https://doi.org/10.13984/j.cnki.cn37-1141.2023.06.010

  Abstract ( ) PDF ( )

  Microbial community and diversity of water and sediment samples were investigated by the 16S rRNA gene based on a high-throughput sequencing platform. Results showed that the species annotation OTU (Operational taxonomic unit) numbers of Daihai water and sediments were 3 253 and 640 respectively, and the bacterial community in the sediments are more diverse than that in the water body. The bacteria species in the sediments of Daihai Lake belong to 58 phyla (782 genera), and the dominant groups are Proteobacteria (49%), Bacteroidetes (11), Chloroflexi (8%) and Firmicutes (6%). The bacteria in the water are assigned to 29 phyla and 318 genera, and the dominant populations are Actinobacteria (45%), Proteobacteria (26%), Bacteroidetes (16%) and Tenericutes (13%). ANOSIM test showed that there was a significant difference in the bacterial community structure between the sediment and the water samples of Daihai Lake. Salinity is a major constraint to the bacterial diversity in lakes. The higher abundance of Proteobacteria, Bacteroidetes, cyanobacteria, Planctomycetes, which showed the deterioration trend of water samples.
• Decomposition dynamics of three macroalgal species inhabiting Gouqi Island seaweed bed

  LIU Zhangbin, WANG Kai, CHEN Yifan, LI Xunmeng, ZHANG Shouyu

  2023, 45(6): 83-90. https://doi.org/10.13984/j.cnki.cn37-1141.2023.06.011

  Abstract ( ) PDF ( )

  It is of great significance to study the decomposition process and nutrient dynamics of macroalgae for understanding the material cycling process in the seaweed bed ecosystem. Through outdoor decomposition simulation experiment, the changes of nutrient components in the decomposition process of the dominant species Sargassum horneri, Grateloupia livida and Ulva lactuca L. and the decomposition of three macroalgae at different temperature gradients were analyzed. Measurement results demonstrated that the decomposition rate of G. livida was the fastest, which was followed by that of S. horneri and U. lactuca L. In the decomposition process, the carbon content of three macroalgae fluctuated slightly in the first 24 days of decomposition. The nitrogen content of different macroalgae changed differently, and the phosphorus content declined rapidly at the early stage of decomposition. At the end of the experiment, the phosphorus content decreased. The C/N and C/P of the three macroalgae were similar in general. The C/N ratio decreased in the decomposition process. C/P raised first and then falled down. The change of N/P was a little complicated. G. livida showed an up-down fluctuation while U. lactuca L. and S. horneri showed a process of rising first and then falling. Correlation analysis showed that the higher the C/N ratio of S. horneri, the lower the decomposition rate, the higher the C/P ratio of U. lactuca L., the lower the decomposition rate. The decomposition rate of macroalgae remained different at different temperature gradients. The higher the temperature, the faster the decomposition of macroalgae. Our findings indicated that the aged and apoptotic algae should be salvaged in macroalgal culture areas and marine reserves in time, especially in summer when the temperature becomes high. It is necessary to deal with the decaying macroalgae properly to avoid the secondary pollution to the ocean.
• Effects of dissolved oxygen and sediment on decomposition of Sargassum thunbergii debris

  CHEN Yifan, WANG Kai, LIU Zhangbin, ZHAO Xu, CHENG Xiaopeng, ZHU Yue, ZHANG Shouyu, LIU Hongsheng

  2023, 45(6): 91-99. https://doi.org/10.13984/j.cnki.cn37-1141.2023.06.012

  Abstract ( ) PDF ( )

  Sargassum thunbergii, the dominant macroalgal species inhabiting Gouqi Island, was selected as the researching object to explore the release of macroalgal nutrients and the effects of dissolved oxygen and sediment on its decomposition during the process of litter decomposition and detritus formation through indoor experimental simulation. The results showed that S. thunbergii decomposed rapidly at the early stage of decomposition; the dry matter loss rate was high and the contents of orthophosphate and active acid salt in water increased significantly. The dry matter residue rate of S. thunbergii was significantly correlated with the decomposition time (P<0.01). After 48 days, the dry matter residue rate of S. thunbergii was lower than 30%. High oxygen condition promoted the decomposition of S. thunbergii and the release of inorganic nitrogen and reactive silicate. Under low oxygen condition, the decomposition of S. thunbergii reduced the pH of water and promoted the release of orthophosphate. At the later stage of decomposition, the absorption rate of nutrients by microorganisms in sediment was higher than that of algal decomposition, and the content of nutrients in water gradually decreased. The decomposition process of S. thunbergii was affected by the dissolved oxygen content and substrate conditions. Our findings may serve as a basis of exploring the effect of macroalgal decomposition on the ecosystem service efficiency of algal farms inhabiting the island and reef waters.
• Effects of salinity and acidity on oxygen consumption and ammonia excretion rates of Coelomactra antiquata

  LUO Jie, WANG Zhongduo, CAO Fujun, LIANG Libin

  2023, 45(6): 100-108. https://doi.org/10.13984/j.cnki.cn37-1141.2023.06.013

  Abstract ( ) PDF ( )

  At salinities (12, 17, 22, 27, 32 and 37) and acidities (pH5.0, 6.0, 7.0, 8.0, 9.0 and 10.0), the effects of large (L), medium (M) and small (S) of C. antiquata on oxygen consumption and ammonia excretion rates were studied with experimental ecological method. The results showed that salinity has a significant effect on the oxygen consumption rate of C. antiquata (p<0.05), and a very significant effect on ammonia excretion rate (p<0.01). Within the salinity range set, the oxygen consumption rate of C. antiquata rised with the increase of salinity when the salinity varied between 12 and 22, and maximized at 22 and decreased with the increase of salinity. The ammonium excretion rate reached its maximum when the salinity was 27, and then decreases with the increase of salinity. Acidity had significant effects on both oxygen consumption rate and ammonia excretion rate of C. antiquata (p<0.05). With the increase of acidity, the oxygen consumption rate and ammonia excretion rate of C. antiquata increased first and then decreased, reached the maximum at pH8, and then decreased gradually. Under the same salinity or acidity, the oxygen consumption rate and ammonium excretion rate of C. antiquata of different specifications decreased with the increase of unit body mass, and unit body mass had a very significant influence on the oxygen consumption rate and the ammonia excretion rate (p <0.01). In the salinity experiment, the O:N ratio of the three specifications of C. antiquata ranged from 5.733 to 7.543, increasing first and decreasing then with the increase of salinity. With the increase of acidity, the variation of O:N varied in a similar way of salinity, ranging from 5.722 to 6.574, and reached the maximum at pH 7. The O:N increased with the increase of individual. The change of salinity or acidity had little effect on O:N ratio.
• Research Report
• Analyses of marine environment characteristics of the deep-sea observation sites innorthern South China Sea

  TAN Junfeng, SONG Xiaoyang, ZHANG Fei, YANG Jie, CHANG Yongguo

  2023, 45(6): 109-115. https://doi.org/10.13984/j.cnki.cn37-1141.2023.06.014

  Abstract ( ) PDF ( )

  The CTD and ADCP mounted on the submarine dynamic platform were used to conduct long-term and fixed-point observation of the deep waters in the northern South China Sea. Based on data such as thermohaline and ocean currents, we analyzed the marine environment characteristics by various data processing methods. According to the data analyzed, the temperature and salinity of the deep waters in the northern South China Sea were relatively stable with some seasonal differences, and the main characteristics were low temperature, high salt and high density. The current velocity ranged from -100 mm/s to 100 mm/s, and mainly about 50mm/s. The current velocity was inversely proportional to water depth, forming a typical deep ocean velocity profile. Tidal current harmonic analysis demonstrated that tidal currents are dominated by diurnal and semidiurnal tides, and the flow ellipse rotated with depth and changed in a complex way. Different vertical modes were calculated based on the Empirical Orthogonal Function (EOF) analysis of the eastern and northern components of the tidal currents, with a variance contribution for the first two modes of at least 85%, higher order modes were less than 5%. The results revealed a strong barotropic character for the tidal currents of this region.
• Water environment carrying capacity of Dachen Island sea area, Taizhou

  WANG Zuanyi, LI Yingdong, ZHENG Xinyun, CHENG Xiaopeng, HAUNG Hong, WANG Zhenhua

  2023, 45(6): 116-123. https://doi.org/10.13984/j.cnki.cn37-1141.2023.06.015

  Abstract ( ) PDF ( )

  Water quality at 20 sites in the sea area of Dachen Island, Taizhou City, was examined in Nov., 2019. The comprehensive pollution index of heavy metals was calculated with improved Nemerow index method, the water quality data were analyzed screened was with principla component analysis method, and the water environment carrying capacity was calculated and evaluated with BP neural network strategy. The results showed that all indexes meet the second grade of seawater quality standard except DIN and PO₄-P; Pb content of individual sites is slightly higher than others, but the overall concentration of heavy metals meet the second grade; the main driving factors of water environment quality are DIN, PO₄-P, COD_Mn, DO, comprehensive pollution index of heavy metals and petroleum hydrocarbons. The water environment carrying capacity revealed by BP neural network was spatially heterogeneous, being lower in the northwest sea area and increasing to the southeast with the increase of the distance from the island. The water environment carrying capacity of the ecological protection zone was capable, and the water quality met the requirements of marine ranching construction. While the human activity area was slightly overloaded, the monitoring and management of water quality should be strengthened.
• Assessment of marine ecological risk of Beibu Gulf sea area based on pressure state response model

  WU Ni, SUN Qingyang, HUANG Huamei, HUANG Youjia, PAN Jingyun, MIN Tingting, ZHANG Liuli, CHEN Mianrun

  2023, 45(6): 124-132. https://doi.org/10.13984/j.cnki.cn37-1141.2023.06.016

  Abstract ( ) PDF ( )

  In this study, an ecological risk index system based on the pressure-state-response (PSR) model was developed to evaluate the marine ecological risk of Beibu Gulf sea area, Guangxi. Fifteen representative indicators were picked up for the ecological risk index system. Analytic hierarchy process (AHP) was used to obtain weights of the selected indicators. Marine risk index was calculated using synthetic index method. The result showed that the marine risk of Beibu Gulf sea area was at the level of early warning. Optimistically, the marine risk presented a declining tendency in recent 10 years. Some marine risk management countermeasures were put forward for marine sustainable development, which included science-based and strictly controlled land reclamation, controlling land-based pollution, controlling alien species invasion, controlling the population of coastal cities, reinforcement of coastline renovation and restoration among others.
• Ecological safety assessment of Dishui Lake and its diversion channels based on PSR model

  HU Jingyang, YUAN Lin, CHEN Yan, ZHANG Yu, XUE Junzeng, CHEN Chong, CHEN Jiajie, HU Qianye

  2023, 45(6): 133-141. https://doi.org/10.13984/j.cnki.cn37-1141.2023.06.017

  Abstract ( ) PDF ( )

  Ecological safety construction is an important foundation for our country to achieve sustainable development. No research has been carried out for the ecological safety of Dishui Lake and its diversion channels including many rivers and dense water networks. In this study, we constructed an ecological safety evaluation index system suitable for the Dazhi River-Dishui Lake basin based on the water environment monitoring data collected at 23 sampling points from Sept. 2018 to Aug. 2020 and the PSR model. During the evaluation of the ecological security status, relevant methods such as principal component analysis (PCA) and entropy method weighting were used. The evaluation results showed that the ecological safety level of the water diversion source area of Dazhi River is at level II, which is relatively unsafe; the ecological safety level of the main urban area of Lingang New City is at level III, which is in a critically safe state; the ecological safety level of the Dishui Lake area is at level III, which is in a critically safe state. Comprehensive assessment of the ecological safety level of the Dazhi River-Dishui Lake Basin covering the Dishui Lake and its diversion channels is at level III, which is in a critically safe state.
• Seasonal variation of phytoplankton community and its relationship with environmental factors in the influent rivers of Dishui Lake

  CHEN Yan, YUAN Lin, HU Jingyang, ZHANG Yu, XUE Junzeng, CHEN Chong, CHEN Jiajie, HU Qianye

  2023, 45(6): 142-151. https://doi.org/10.13984/j.cnki.cn37-1141.2023.06.018

  Abstract ( ) PDF ( )

  In order to clarify the spatial and temporal distribution of phytoplankton community and its relationship with environmental factors in the influent rivers of Dishui Lake, twelve sampling sites were set up at the lake inlet, Neilian River, Zhonglian River and Wailian Rivier, and the phytoplankton there were field surveyed from Sept. 2018 to Aug. 2019. In total, 8 phyla, 93 genera and 232 species of phytoplankton were collected in the survey area. Among the total, species in Chlorophyta accounted for 41.81%, species in Bacillariophyta for 22.41%, species in Cyanophyta for 18.97% and species in Euglenophyta for 11.64%. The number of phytoplankton species in Neilian River and Zhonglian River was high, especially in the sample 8. The phytoplankton density ranged from 584×10⁴ cells/L to 1985×10⁴ cell/L. The phytoplankton was mainly composed of Chlorophyta and Cyanobacteria, with the highest density documented in spring and the lowest in winter. The phytoplankton density in the second route of Neilian River was significantly high than that in other sampling sites. Pearson correlation analysis showed that pH, DO, TN and NO^-₃-N were the main factors affecting phytoplankton density, but there was no correlation wss found between the density and sal, NO^-₂-N and SD. Canonical correspondence analysis showed that WT, DO, TN, NH⁺₄-N and NO^-₃-N are the main factors affecting phytoplankton composition.
• Research Review
• On feasibility of power expansion of International Seabed Authority to manage BBNJ issues

  ZOU Leilei, HAO Zhijian

  2023, 45(6): 152-160. https://doi.org/10.13984/j.cnki.cn37-1141.2023.06.019

  Abstract ( ) PDF ( )

  Issues on biodiversity of areas beyond national jurisdiction (BBNJ) have entered into the final intergovernmental negotiation stage, but the BBNJ management subject has not been decided yet. In this paper, we argue that power expansion of the International Seabed Authority (ISA) could be a feasible option. ISA has accumulated much experience in managing the mineral resources in the Area, protecting the marine environment, and promoting and encouraging marine scientific researches,which will shed light on its BBNJ management. There is also legal basis for the implied power expansion of ISA, and BBNJ agreement could also authorize ISA with new power. If ISA takes up the BBNJ management, it will help to prevent the overlapping of jurisdiction from different authorities over the Area. ISA has also accumulated much experience in zoning, environmental impact assessment, capacity building and technology transfer, which will shed light on its BBNJ management as well. In addition, as a platform for extensive international cooperation, ISA has developed a good mechanism, which will also facilitate its BBNJ management.
• Proceedings of fisheries biology and assessment of Jack mackerel (Trachurus murphyi) inhabiting South Pacific

  ZHANG Chang, LI Gang, CHEN Xinjun

  2023, 45(6): 161-170. https://doi.org/10.13984/j.cnki.cn37-1141.2023.06.020

  Abstract ( ) PDF ( )

  Jack mackerel (Trachurus murphyi) is an important economic fish species with a wide range of distribution, which is one of the main fishing targets in many countries and regions. In this study, the biological research progresses in the population structure, migration, growth, reproduction and feeding studies of jack mackerel inhabiting the South Pacific were preliminarily reviewed, which will provide a basis for systematically mastering the basic biology and management of this fish species. The migration pattern of this fish species is complex, and the population structure of this fish species is still controversial. Jack mackerel predates a variety of species. Its day and night vertical movement is related to the feeding habits. The fish species has multiple spawning grounds in both coastal waters and the high seas. Jack mackerel has an obvious diurnal vertical migration habit, and two types of horizontal migrations, seasonally from high seas to coastal waters and geographically New Zealand coasts to Chilean coasts on large scales. However, the specific migration patterns are still unclear, waiting for more studies. Many environmental factors like ocean currents, water masses, mesoscale eddies of different natures, sea surface temperatures, wind and salinity affect the resource of jack mackerel. In order to rationally develop and use jack mackerel resources in the future, it is necessary to continuously strengthen the cooperation among countries and regions, systematically surveying and studying the jack mackerel resources in the south Pacific Ocean, and take the impact of the environment on jack mackerel resources into account, so that a theoretical support for the sustainable use and scientific management of this fish species can be provided.
• Ecosystem-based integrated coastal zone management: A case study of Zhanjiang City, Guangdong Province

  CHU Xiaolin, ZHANG Haoyue

  2023, 45(6): 171-179. https://doi.org/10.13984/j.cnki.cn37-1141.2023.06.021

  Abstract ( ) PDF ( )

  Ecosystem-based integrated coastal management is the overall consideration of the interaction of various factors in marine ecosystem, and the comprehensive use of legislation, planning and law enforcement to achieve the sustainable management of marine environmental resources. As an important coastal development city for the “Belt and Road” construction and an important growth pole of the marine economy in Zhanjiang City, Guangdong Province is a representative in the implementation of integrated coastal management based on the ecosystem. With the rapid development of Zhanjiang's marine economy, its coastal environmental resources have also been suffering increasingly serious damage. However, Zhanjiang's current coastal management has not yet implemented the ecosystem concept, and our aspects including coastal legislation, coordination mechanisms, law enforcement forces and public participation are problematic. In response to these problems, the following countermeasures are proposed, which included formulating coastal zone protection regulations, establishing a coastal zone coordination mechanism, establishing a coastal zone joint law enforcement mechanism, and encouraging the public participation in coastal zone protection, so that the integrated coastal zone management of Zhanjiang City can be strengthened.
• On theconstruction mode and approach of “marine granary” of east Shandong Peninsula in new era

  WANG Xuehui, YIN Zhaolu

  2023, 45(6): 180-188. https://doi.org/10.13984/j.cnki.cn37-1141.2023.06.022

  Abstract ( ) PDF ( )

  From the beginning of the new era, Chinese government encourages advancing the development of the socialism with Chinese characteristics by establishing five developmental concepts, innovation, coordination, green, opening, and sharing, and strongly supports the idea of ‘healthy China' and “big food”. The constructing marine granary will effectively and systematically coordinate the constructions of ecological civilization, food security and modern fishery. The new development model explored during the construction of marine granary of east Shandong Peninsula included coordinated development of resource exploitation with ecological protection, synergistic integration of modern management and technical supporting, simultaneous improvement of fishery proliferation and quality, collective development of public service and policy supporting, and promotion of fishery transformation and upgradation of the east Shandong Peninsula to be ecological, scalable, systematic, and standardized. In the new era, we are required to utilize the Marxist Theory and Xi Jinping's Thoughts on Marine Power to explore the new mode of constructing marine granary of east Shandong Peninsula.
• Researching progress of Chinese marine ranches based on bibliometric analysis

  YU Jiayue, JIA Tianyu, WANG Chunrui, LI jun, WANG Jiaqiao, LIU Xiande, HUANG Liangmin

  2023, 45(6): 189-197. https://doi.org/10.13984/j.cnki.cn37-1141.2023.06.023

  Abstract ( ) PDF ( )

  Marine ranches have been evolving as the fishery models in China. In this study, we retrieved 481 documents from CNKI, analyzed their publication, theme, discipline, researching levels and fund distributions, and drew the author's cooperative network analysis and keyword emergence maps using CiteSpace software. The results showed that the researches relating to marine ranches in China meet the policy requirements, the number of literature keeps rising in a fluctuation way, and the multidisciplinary integration researches have aided to breaking the researching bottleneck. It is necessary to increase the collaborative scientific researches among universities, research institutes and management departments to ensure the support of the technical system. The researches in future will be policy-oriented, aiming to fill the gaps in monitoring and assessment mechanisms of marine ranches. More attentions should be paid to ecological efficiency and modernization.
• Studies on the fishery administrative law enforcement and criminal justice convergence mechanism: the crime of illegally catching aquatic products as an example

  WANG Xiaojun, WANG Lu, LI Wenlu

  2023, 45(6): 198-207. https://doi.org/10.13984/j.cnki.cn37-1141.2023.06.024

  Abstract ( ) PDF ( )

  Strengthening the convergence of fishery administrative punishment with criminal justice is an inevitable requirement for effectively combating fishery illegal and criminal activities. It is of great significance for strengthening fishery management according to law and maintaining ecological safety. In this article, we take the crime of illegally fishing aquatic products as the starting point and analyze the problem of poor connection of execution in the practice of fishery law enforcement in our country. At present, the main reason for the poor connection of fishery law enforcement in our country is the incoordination of relevant legislation and the uncoordinated mechanism of fishery execution connection procedures. It is necessary to improve relevant legislation, clarify the transfer procedures and evidence conversion standards of fishery execution connection cases, and establish a law enforcement information sharing mechanism. We must improve the fishery administrative punishment and criminal justice convergence mechanism in three aspects.
• Dual alienation dilemma of the appraisal system of river chief system and its legal regulation

  ZHANG Zhiguo

  2023, 45(6): 208-214. https://doi.org/10.13984/j.cnki.cn37-1141.2023.06.025

  Abstract ( ) PDF ( )

  The appraisal system of river chief system is fundamental for the effective running of river chief system; however, there is a dual alienation dilemma found in its original designing and practical running. At the beginning of its designing, there were some problems in its appraisal system like the theoretical dilemma of rationality, the doubt of the scientific nature of the assessment accountability system, and the fuzziness of the top-level design. During its practical running, there were some problems also in its appraisal like the virtual assessment, the incomplete assessment mechanism and the unfair assessment results. The reasons for the dual alienation dilemma included the inherent deficiency of the river chief production as an emergency system, and the problems of imperfect and unclear legal provisions. The legal regulation of the dual alienation dilemma of the river leader system include the special legislation of the river chief system at the national level, and the ability building of the administrative law enforcement team to improve the law enforcement. More importantly, improving the legal awareness of social environmental protection and broadening the public participation channels in environmental protection are absolutely necessary.