This paper proposed a new method of measuring coefficient of friction using the texture feature value extraction technology in image recognition. The texture feature value was used to characterize and quantify the roughness of the surface of an object, so as to obtain the coefficient of friction of the surface of the object. This method can be utilized to solve the problem that is difficult to measure the friction coefficient conveniently in the caisson sliding experiment. The friction coefficient of concrete test block was measured through physical model test, and the relationship between image texture feature value and coefficient of friction was analyzed. The results showed that there was a good correlation between the image texture feature value and the coefficient of friction. Using the functional relationship between image texture eigenvalues and friction coefficient established on this basis, the measurement of friction coefficient can be simplified.

In this paper, a storm surge and wave coupled inundation simulation model at high resolution was established based on the ADCIRC (a parallel advanced circulation model for oceanic, coastal and estuarine waters) and the SWAN (simulating waves nearshore) ocean numerical models, which was applied for the simulation and calculation of the typhoon-induced storm surge in Wenchang. Based on Typhoon Kalmaegi (No. 1415), a series of paths were designed to perform sensitivity analysis of landing location. The results showed that the landing location had a significant impact on the storm surge. We also designed different intensity path sets to calculate the storm surge and perform hazard assessment. The results showed that the stronger the typhoon intensity, the larger the submerged range, the deeper the submerged depth, and the larger high-risk area. With the decrease of typhoon intensity, the submerged area gradually decreased. However, due to the low terrain of Bamen bay and Puqian bay, under the intensity of 990 hPa, there was still more than 1.2 m submerged depth, which was easily submerged. It is a vulnerable area and needs more attention and prevention.

Coastal ecosystems such as salt marshes and mangroves can effectively dissipate wave energy and reduce the risk of coastal disasters caused by waves. Accurate prediction of wave attenuation caused by vegetation is of significant importance for the design of nature-based coastal protection engineering. This study is based on the open-source fully nonlinear Boussinesq equation model FUNWAVE-TVD, incorporating the momentum dissipation term caused by vegetation to simulate wave attenuation by vegetation. The model uses results from 6 different physical model experiments and 113 sets of experimental data for simulation and validation, and determines the optimal vegetation drag coefficient C_D. The results show that the model can accurately quantify the attenuation of wave height by vegetation, and that the optimal vegetation drag coefficient C_D varies greatly under different experimental conditions. The calibrated drag coefficients are compared with several mainstream empirical formulas for vegetation drag coefficients in the literature, and the effective calculation method of C_D in numerical simulation of vegetation wave attenuation is discussed. The study can provide technical support for the synergy of coastal disaster protection and ecological restoration.

Based on the measured wave data of Yangjiang sea area for one year(September 1,2021 to August 31,2022), the characteristics of wave parameters are statistically analyzed, and the correlation between wave parameters is fitted and analyzed by the least square method. The results show that: (1)The annual average significant wave height is 0.82 m, the annual average period is 3.8 s, the annual maximum wave height is 10.98 m occurs during the transit of typhoon “Ma-on” in August 2022. (2)The study area is dominated by light waves, accounting for 74.15%; the normal wave direction is SE, the secondary normal wave direction is ESE and SSE; and the strong wave direction is ESE; the significant wave period is mainly 4~8 s; the normal wave direction is dominated by light waves with a period of 4~8 s. (3)There is a good linear correlation between characteristic wave heights. (4)During the transit of typhoon “Ma-on”, the wave spectrum is dominated by double peak spectrum, with the maximum spectrum peak of 53.79 m²/Hz and the corresponding spectrum peak frequency of 0.18 s.

The local scour characteristics of pile foundation and the protective effect of sandbag throwing are studied when the pile foundations of jack-up platform are shallow in mud. By simplifying the wave-flow interaction, Flow-3D numerical simulation software was used to obtain the scouring condition of pile boot when it was immersed in mud at 1.5 m and 3.0 m. Numerical simulation results show that local scour is mainly distributed on both sides of the pile boot, and the silt is formed behind the pile boot, and the scour depth can reach 3.5 m and 2.95 m respectively. Local scour affects the seabed bearing layer near the pile boots and reduces the stability of the jack-up platform, which requires scour protection. The sand bag protection was used to protect the pile foundation of jack-up platform from scour, and Flow-3D numerical simulation was used to obtain the scour results under sand bag protection when the pile boot was immersed in mud at 1.5 m and 3.0 m. It was considered that the scour protection effect of sand bag was better.

In order to investigate the seasonal stability of remote sensing image fusion models in the nearshore region, the Landsat panchromatic (PAN) data and MODIS multispectral (MS) data from four seasons were fused in five ways: nearest neighbour diffusion (NNDiffuse), ratio transform (Brovey), colour transform (HSV), phase recovery (Gram-Schmidt) and principal component analysis (PCA). The quality of the fused images was evaluated in terms of qualitative, quantitative and applicability, and the seasonal stability of the remote sensing fusion model was analyzed using variance (S²). The results showed that in terms of qualitative evaluation, NNDiffuse, Brovey and HSV had high seasonal stability and good fusion effect. In terms of quantitative evaluation, nine quantitative evaluation indexes were selected. Using normalization to calculate the integrated evaluation index, the HSV fusion model S² was 2.4×10^-3, which had high stability and could significantly improve the remote sensing image quality in all seasons in the nearshore region. In terms of the inversion accuracy of chlorophyll concentration, the S² of HSV fusion model was 4.9×10^-3, which had high stability among the four seasons and was correlated well with the measured chlorophyll concentration (R²>0.619). Therefore, the HSV fusion model with high seasonal stability, good fusion quality and high accuracy of chlorophyll inversion was the optimal model for nearshore remote sensing image fusion.

In this paper, three columnar sediment cores in the southern waters of the Shandong peninsula and 19 surface sediments in four small rivers in the southern part of the Shandong peninsula were used as research objects to identify the sediment sources in the argillary region of the southern Shandong peninsula through systematic analysis of the geochemical characteristics of rare earth elements. According to the 210Pb test results, the sedimentation rates of Z02, Z10 and Z16 in the argy region of the southern Shandong peninsula were 0.621 cm/a, 0.36 cm/a and 0.4 cm/a, respectively. The standardized results of chondrites showed that the core sediments in the study area showed a negative slope right-leaning pattern of light rare earth element enrichment and a loss of heavy rare earth element. Eu was obviously negative abnormal. The results of the DF calculation of the source discriminant function showed that the contribution of the Yellow River sediment in the past 300 a was significantly reduced, and the contribution of small and medium-sized rivers in the Shandong peninsula was increased, which may be affected by the decrease of the sediment of the Yellow River into the sea.

Apostichopus japonicus Selenka is a commercial species in China. During its larval development, it experiences body color change stage important for its development. Current studied centralized on the mechanism underlining white and purple body color of A. japonicus while that underlining the common green color was scarce. The transcriptomes at early (JW), mid- (JV), and late- (JB) pigmentation stages were sequenced and compared to find the differentially expressed genes (DEGs). A total of 252,397 genes were obtained by sequencing. The number of DEGs (JW vs. JV) was 10,266 while that of DEGs (JW vs. JB) was 12, 811 and that of DEGs (JV vs. JW) was 9,657. GO and KEGG analyses showed that the genes such as those encoding calmodulin, protein kinase C, putative tyrosine kinase receptor Cad96Ca, and putative tyrosine kinase differentially expressed during the change of body color of juvenile A. japonicus. It was speculated that Ras, Wnt, MAPK signaling pathways among others are involved in the melanin synthesis of juvenile A. japonicus. Our findings provided valuable information for in depth studies on the molecular mechanism of the pigmentation of A. japonicus with different body colors.

Caspase-dependent apoptosis plays an important role in immune defense and degeneration of metamorphic larvae-specific structures of marine invertebrates. However, studies on caspase-mediated programmed death regulating immune response and early development in Apostichopus japonicus are scarce. In this study, qRT-PCR was used to detect expression level of pro-apoptotic caspase-2, -3, -6, -8 genes in tissues and at early developmental stages of A. japonicus. The results showed that in contrast to gonad where these genes express at the lowest level, the expression level of caspase-3, -6, and -8 mRNA was the highest in coelomocytes while that of caspase-2 was the highest in tube feet and respiratory trees (P <0.05). The expression of caspase-2, -3, -6, -8 was continuous at a low abundance during the cleavage stages from fertilized egg to gastrula, which increased from auricularial phase (P <0.05). With the rapid enhancement following a metamorphosis process, their expression peaked at the postmetamorphic juvenile stage, significantly higher than that at other stages (P<0.05). Our findings indicated that apoptotic caspases are likely to be essential in the immune response and metamorphosis of echinoderms like A. japonicus.

Suspended soils (SS) are the main factor causing physical clogging during artificial recharge. Dissolved organic matter (DOM) exists widely in recharge water and aquifer. It is of great scientific significance and application value to study the influence of DOM on physical clogging. One-dimensional seepage simulation experiments were used to explore the influence of low concentration (1 mg C/L) humic acid (HA), a representative DOM, on the transport and deposition behavior of SS in porous media, and on the physical clogging during artificial recharge. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and dynamic light scattering (DLS) were used to reveal the influence mechanism of HA on physical clogging in porous media. The results showed that after adding HA, the transportability of SS was enhanced, the deposition amount of SS was reduced, and the physical clogging in porous media was inhibited. When HA was adsorbed on the surface of kaolinite, the steric hindrance effect between kaolinite was enhanced, and then the agglomeration between kaolinite was reduced, thus enhancing the dispersion stability of kaolinite.

When the receiver is stationary and the sound source is moving uniformly along a straight line at the same depth, the phase of the received sound pressure signal in the frequency domain changes nonlinearly with time, and the phase linearization can be realized by using warping transform. Firstly, the Warping operator under different motion parameters was constructed, and then the operator was used to resampling the received sound pressure in the frequency domain. Finally, the corresponding wave number spectrum was obtained by Fourier transform of the resampling sound pressure. Therefore, the maximum spectral energy of wave number in a specific interval could be used to estimate the velocity of sound source. In addition, under the condition of low SNR, a speed-wave number spectral energy graph was proposed to estimate the velocity of sound source. Experimental and simulation data verify the effectiveness of the above methods.

As one of the important economic cephalopods in Zhejiang coastal waters, Sepiella maindroni plays an important role in ecosystem. Its hard tissue, beak, can be used as an important material for the studies of fishery ecology. Morphological and growing characteristics of 494 pairs of beaks of S. maindroni were studied. The principal component analysis showed that the upper hood length (UHL), the upper crest length (UCL), the lower crest length (LCL) and the lower wall length (LLWL) can be selected as an analysis parameters of external morphological characteristics of beak. Covariance analysis (ANCOVA) showed that there is significant difference among all external morphological parameters and between sexes (P<0.01). Akaike's information criterion confirmed that the power function is the best for describing the relationship between mantle length (ML) and UCL, ML and LLWL of males and females, and that of ML and UHL of females. The relationship between LCL and ML of females was optimally described by the exponential function while that between UHL and UCL of males was best fitted with ML by logarithm function. The absolute growth and the relative growth rates of beaks decreased when the daily age of S. maindroni increased with their minimum value appeared at 86 to 95 daily age. The determination of external morphological analysis parameters of beaks and its relationship with ML can be used to identify the populations of S. maindroni. In addition, the growth characteristics of beaks can provide a scientific basis for the studies of feeding ecology in large-scale cultivation of S. maindroni.

Heterocapsa bohaiensis perform a significant toxic effect on Brachionus plicatilis; however, the toxins of H. bohaiensis are not known yet. In addition, whether the algal toxins are stable or not during extraction, separation and identification is crucial. To explore the extraction condition of the toxins of H. bohaiensis, the toxicity of its crude extracts on B. plicatilis was evaluated for a set of extraction and preservation conditions in this study. The results indicated that H. bohaiensis toxins are intracellular; a similar rotifer mortality is found in algal cells and ruptured cell suspension but not in cell-free filtrates. Temperature impacted on the algal toxin. It was found that the toxins are most stable at 25℃. Light condition was not concerned with the toxicity of H. bohaiensis. Acetonitrile crude extract from ruptured cell suspension showed the heaviest toxic effect. The maximum absorption wavelength of acetonitrile extraction was 442 nm which is usable in detection during toxin separation. The extraction and preservation conditions of H. bohaiensis toxins were figured out in this study, which will contribute to isolating and structurally identifying the toxins in further.

The long-term trends of sea surface chlorophyll and sea surface temperature of northwest Pacific were analyzed. The time distribution of chlorophyll was divided into bloom outbreaking and non-outbreaking times with the defined threshold method. It was found that the annual algal bloom days have a short oscillation due to the periodic sea surface temperature change (ENSO), and a downward trend of 2.80 D/y. The observation sea areas included three sites on the longitude section near the Hokkaido fishing ground. The trend analysis showed that the outbreaking time of algal blooms in spring comes first each year, with an average advancing time of 0.6 days/year, and the algal bloom in northwest Pacific may come earlier and sustain shorter in future. When studying the impact of climate change on phytoplankton in northwest Pacific, we should consider the factors of periodic fluctuations of sea surface temperature and changes of phytoplankton phenology.

River pollutant flux estimation can provide scientific and technical support for environmental management such as marine water quality early warning and total control. However, the frequency of river water quality monitoring was currently low, and the common low-frequency manual monitoring data of 1-2 times per month could not meet the requirements of accurate pollutant flux estimation. In order to improve the accuracy of the pollutant flux estimation results of the Yellow River, this paper established the regression equation between pollutant fluxes and fluxes based on LOADEST model to estimate the fluxes of major pollutants such as COD, total nitrogen, total phosphorus and oil in the river, using the daily flow data and monthly water quality data of the Lijin section of the river from 2009 to 2019. The results showed that the average annual fluxes of the above four major pollutants in the Yellow River were 31×10⁴ t/a, 8.9×10⁴ t/a, 1.4×10⁴ t/a and 2.5×10² t/a respectively, and the intra-year distribution of fluxes was closely related to the flood season, with the highest monthly flux in July and the lowest in February. The uncertainty in the estimation of COD fluxes to the sea in the river was the smallest, within 15%, and the uncertainty in the oil was the largest, around 30%-50%. LOADEST model gave excellent results for COD, TN and TP, but the results for oil were poor, so it is not recommended to use LOADEST model to estimate oil fluxes in preference.

In this paper, the influence of clay content and penetration rate on the critical state parameters and consolidation coefficient of silty soil in the Yellow River delta was discussed by using the laboratory geotechnical test method, and the calculation method of the critical state parameters of silty soil in the Yellow River delta was summarized. Based on the CPTU experiment, the influence law of clay content on the skeleton curve of rate effect of silty soil was discussed. The “N_kt-V” and “B_q-V” rate effect of silty soil with different clay content was summarized by adopting the normalized penetration rate V=vD/c_v. The results showed that the boundary between fully drained and partially drained regions was V=0.45, and the boundary between partially drained and completely undrained regions was V=30. The recommended values of the cone-tip resistance coefficient N_kt for the reconstructed silty soil without drainage were 9.6~10.3, which could be used for the inversion of the strength parameters of silty soil in the Yellow River delta region. The research results can provide reference for the evaluation of seabed stability in the region.

Under the background of increasing attention to marine ecological environmental protection, ecological revetment has become the development trend of current revetment design. Selecting a suitable type of ecological revetment to repair and renovate the damaged shoreline can reduce the adverse impact of the project implementation on the ecological environment of the coastal waters, and it is also conducive to the protection of biodiversity in addition to the function of preventing tides and waves. The shoreline renovation and restoration project from the Weihe river estuary to the Jiaolai river estuary in Changyi city selected the type of fence panels revetment to repair the damaged seawall. It was shown that the ecological revetment type had limited impact on the surrounding marine ecological environment, and it was feasible to use this restoration type to remediate and restore near the coastline.

As the important hard tissues of cephalopods, the beak has the characteristics of stable structure and corrosion resistance, and stores a wealth of growth information. In northwest Pacific, Watasenia scintillans is not only important in terms of commercial value, but also the food of marine mammals and fishes. The studies on the characteristic parameters such as the morphology and pigmentation area of beak should aid to the further studies of growth rhythm and feeding behavior transformation. In this study, 156 species of W. scintillans collected in northwest Pacific in July, 2021, were selected as experimental samples. Morphological length, pigment deposition area and individual mantle length were measured, and the phenotypic change was studied. The results showed that the external morphological data and the proportion of pigmentation of beak increased with the increase of mantle length. Morphological parameters increased significantly when the mantle length was 22, 27 mm, especially the upper hood length, upper crest length, upper lateral wall length and lower lateral wall length. The proportion of pigmentation of upper and lower beak saltated in 26 mm. The phenotypic change of beak between three mantle length groups showed a significant difference (P < 0.05).

Aquaculture wastewater is produced during the aquaculture process of maricultured animals, which may lead to eutrophication and pollution of seawater environment when discharged directly. Macroalgae, as the primary producers in marine ecosystem, can absorb nitrogen and phosphorus and reduce the eutrophication of seawater effectively. In this study, two economic macroalgae, Ulva lactuca and Eucheuma denticulatum, were choosed to absorb nitrogen and phosphorus in aquaculture wastewater. Orthogonal experiment was performed to explore the effect of four factors, combination of macroalgae, ratio of nitrogen phosphorus, type of nitrogen source and concentration of inorganic nitrogen. The optimal combination scheme for the treatment of aquaculture tail water was obtained and applied to the treatment of aquaculture tail water, and a certain economic seaweed yield was obtained at the same time. The best combination of different nutrients was obtained by orthogonal experiment. For the absorption of NH₃-N, the best combination was U. lactuca and E. denticulatum (layered) + ratio of nitrogen phosphorus 6∶1 + NH₃-N + concentration of inorganic nitrogen 200 μmol/L. For the absorption of NO₃-N, the best combination was U. lactuca + ratio of nitrogen phosphorus 12∶1+NO₃-N+concentration of inorganic nitrogen 150 μmol/L. For the PO₄-P absorption rate index, the best combination is E. denticulatum + ratio of nitrogen phosphorus 3∶1+NH₃-N∶NO₃-N 1∶1+concentration of inorganic nitrogen 200 μmol/L. During absorbing N and P, the two economic seaweeds also maintained a high daily growth rate with U. lactuca up to 24.46±0.53 %/d and E. denticulatum up to 8.11±0.15 %/d. The optimal scheme was selected to treat the aquaculture wastewater produced in mariculture farm. According to the discharge requirement of aquaculture tailwater of Hainan Province, China (local standards DB46/T 475-2019), the first-level discharge standard of inorganic nitrogen should be less than 35.7 μmol/L, the secondary discharge standard of active phosphate should be less than 3.12 μmol/L. It was found that the inorganic nitrogen concentration and PO₄-P concentration can be reduced to below the provincial emission standard within 9 days by the selected two optimal combinations. Similar results can also be obtained after reducing the density of macroalgae from 1.0 g/L to 0.7 g/L. In this study, we established an efficient and ecological treatment for aquaculture wastewater with different types of nutrients and also proposed a new model for large-scale, high density and mixed cultivation of U. lactuca and E. denticulatum.

Laizhou bay is an important spawning ground in the Bohai sea and the temporal and spatial changes of chemical oxygen demand (COD) have an important impact on fishery resources and ecological environment. In order to understand seasonal changes of chemical oxygen demand (COD) in Laizhou bay, four on-site surveys were conducted during 2020-2021 and the organic pollution index method was employed to evaluate the survey area. Based on the relevant literature and the monitoring data of our laboratory from 1979 to 2021, the temporal and spatial trend of chemical oxygen demand (COD) concentration in Laizhou bay and its impact factors were discussed. The results showed that the seasonal chemical oxygen demand (COD) concentration in the northern Laizhou bay was lower than that in the south bank, and the high values occurred in the Weihe, Yuhe and Xiaoqing river estuaries. The organic pollution index illustrated that the polluted sea area was the largest in summer and mainly concentrated in the southwest coast of Laizhou bay. The spatial distribution of chemical oxygen demand (COD) in different periods indicated that the area with high chemical oxygen demand (COD) content tended to shrink and was still mainly concentrated in the southwest coast of Laizhou bay. The chemical oxygen demand (COD) concentration in Laizhou bay had shown an “M-type” trend in the past 40 years, and it decreased after 2014 obviously. The land-source transportation of rivers such as the Yellow river and Xiaoqing river, and the rapid economic development around the Laizhou bay had a significant impact on the temporal and spatial changes of chemical oxygen demand (COD). This work can provide scientific basis for further analysis of the spatiotemporal evolution trend of organic pollution in Laizhou bay.

To study the impact of marine ranching construction on ecosystem energy flow and provide a reference for later ecological restoration, the ecological model of marine ranching area and contrast area consisting of 14 and 15 functional group was built with Ecopath model. The data stemmed from the ecological research data of Tianjin Dashentang National Marine Ranching Demonstration Area in Tianjin Shallow-sea area in 2020. the model simulated the ecosystem well. The results showed that the ecosystem structure of the fish marine ranching area is similar with the contrast area, and the benthic organisms are abundant. However, the structure of high trophic level part of food web was simple. Compared with the contrast area, the total primary production/total respiration (TPP/TR), connectance index (CI), system omnivory index (SOI) and Finn's mean path length (FMPL) in the marine ranching area were 1.14, 0.448, 0.255 and 3.942, respectively, better than those in the control area (1.16, 0.408, 0.106 and 3.072, respectively). These findings indicated that the marine ranching makes the structure of the ecosystem more complex, mature and stable. The key species in the marine ranching area were seabirds, Rapana venosa and Eucrate crenata. Through the simulation of the ecological capacity of R. venosa and E. crenata biomass, it was concluded that the ecological capacity of R. venosa under this condition is 21.50 t·km^-2, and the current biomass has exceeded the maximum sustainable yield, 10.75 t·km^-2. The follow-up work should focus on the introduction of other medium andswimming animals at high trophic levels, so that the growth of economic benefits and the improvement of ecological restoration efficiency can be achieved.

In order to explore the purification effect of rice crab cocultivation fields on the circulating water aquaculture system in a coupled system of rice crab co cultivation ponds, the water quality of the inlets and outlets and the intermediate water of in-pond raceway system, rice-crab culture and ecological ditch system were tested in 2021. At the same time, five sites were selected to monitor the water quality of the in-pond raceway system. The studies showed that the variation range of dissolved oxygen in pond raceway system is from 3.59 to 11.3 mg/L, the variation range of phosphate is from 0 to 0.129 mg/L, and the variation range of acidity is from pH 8.43 to pH 9.03. In-pond raceway system can provide water with high dissolved oxygen and purify most of the dissolved phosphate. The rice-crab culture can reduce about 91.79% of ammonia nitrogen and 71.15% of nitrite nitrogen. It can purify the tail water of the in-pond raceway system, which is beneficial to the growth of fish. The coupled system of circulating water aquaculture in rice crab cocultivation ponds is an ideal ecological aquaculture model.

Chlorophyll a (Chl-a) and primary productivity were measured during four expeditions to Miaodao Archipelago in August and October, 2018, April and June, 2019, to characterize their temporal and spatial distribution, and analyze the correlation among Chl-a, primary productivity and main environmental factors. The results showed that the concentration of Chl-a is generally higher in south than in north, and change seasonally. The highest value appeared in June while the higher appeared in August followed that in October and the lowest appeared in April with the average of 4.19±0.75 μg·L^-1, 0.79±0.41 μg·L^-1, 0.75±0.37 μg·L^-1 and 0.27±0.07 μg·L^-1, respectively. High value of primary productivity mainly occurred in the northeastern part of the surveyed area, which varied seasonally. The primary productivity in June was the highest, with an average of 801.86±627.97 mgC·m^-2·d^-1, followed by 204.84±118.76 mgC·m^-2·d^-1 in August, 102.19±77.41 mgC·m^-2·d^-1 in October and 32.07±13.25 mgC·m^-2·d^-1 in April. Correlation analysis among chlorophyll a, primary productivity and main environmental factors showed that nutrient is the important factor affecting the distribution of chlorophyll a around Miaodao Archipelago, and the distribution of primary productivity is closely related to dissolved inorganic nitrogen.

Recreational fishery is one of the five modern fishery industries determined by the 12th five-year plan of national fishery development. In recent years, recreational fishery has developed rapidly in the coastal areas of China. In this study, the grey correlation analysis method was used to select the industry data of recreational fishery and activities associated with recreational fishery performance from 2006 to 2020 in 8 coastal provinces (cities) of China, and compare the industry correlation degree during the period of 11^th, 12^th and 13^th Five-Year Plans. The correlation degree between recreational fishery and related industries in coastal areas shows an upward trend from 2006 to 2020, with an average of 0.6406-0.7456, a moderate to high correlation range. The correlation between recreational fishery and culture, sports and entertainment industry ranked the first in the three periods, >0.6. During 12^th Five-Year Plan, the correlation between recreational fishery and culture, sports and entertainment industry in Shanghai, Zhejiang and Guangdong was higher than 0.8, a high correlation. Compared with 11^th Five-Year Plan, the 12^th Five-Year was a starker choices- and graver consequences-in period with increased leisure fishery industry. Correlated industry included the information transmission, software and information technology services, accommodation and catering industry, water conservancy, environment and public facilities management. The correlation declining industries included the wholesale and retail, transportation, warehousing and postal service. The change of correlation degree of related industries in different regions was obviously different. The development of recreational fishery has the most significant driving effect on culture, sports and entertainment industry, but the driving effect of recreational fishery on related industries is different among periods and regions. It is necessary to further support and promote the integrated development of superior industry and recreational fishery based on local natural resource conditions, and improve the social, ecological and economic benefits of recreational fishery.

Ecosystem-based management emphasizes the balance between protection and utilization, and emphasizes adaptive management and ecological priority, which has guiding significance for coastal zone planning under the territorial spatial planning system. This paper analyzed the relationship between ecosystem-based management and coastal zone planning, and believed that ecosystem-based management could guide coastal zone planning, and the coastal zone planning could enrich the practice of ecosystem-based management. This paper proposed an ecosystem-based coastal zone planning framework, including the determination of management objectives, demarcation of management areas, formulation of management measures, implementation of monitoring and evaluation, and designed an ecosystem-based coastal zone planning path accordingly, in order to provide decision-making support for ecosystem-based coastal zone planning.

Based on the DEA, super efficiency SBM model and Malmquist index, 11 coastal provinces and cities in China were selected as case areas in this paper. The input-output indicators reflecting the development efficiency of marine tourism were used to quantitatively characterize and compare the regional differences of marine tourism development efficiency. The results showed as follows: (1) From the inter provincial and regional level, the temporal and spatial differences of marine tourism development efficiency were significant, and the temporal and spatial regularities were obvious. (2) The utilization capacity and output capacity of marine tourism resources in different regions were quite different. The overall input factors of marine tourism development in coastal areas had a certain degree of inefficient utilization and idle resources. (3) From the perspective of individual provinces, the comprehensive efficiency of marine tourism in Zhejiang maintained a leading position, with a good overall development level, more input and more output. In recent years, the comprehensive efficiency of marine tourism in Guangxi has shown a relatively positive development trend. The comprehensive efficiency of marine tourism in other regions has changed relatively steadily.

In the perspective of the “profound change unseen in a century”, frequent and cutting-edge issues in ocean governance, serious ideological divisions and challenges to governance regulations have been emerging. Global ocean governance is facing numerous contradictions including the mismatch between the supply and demand of public goods, the ideological conflict between neoliberal institutionalism and populism and the misalignment of the rights, responsibilities and capabilities of governance actors. As a specific form of global ocean governance, the South China Sea (SCS) governance is facing severe challenges including legal and institutional deficiencies and geopolitical issues. The COVID-19 pandemic, populism threatening to cooperative governance and intensification of geopolitical competition hindering governance development have put additional pressures on the human-ocean relationship, further exacerbating the contradictions in SCS governance. In the new era, China should fully leverage the enhanced discourse power brought about by the peaceful rise of China, improve the efficiency of governance product provision through the advancement of island and reef functional construction, deepen the construction of governance regulatory systems to safeguard maritime order, and cooperate with ASEAN to develop the blue economy, so that a community of ASC can share the future of the South China Sea, and jointly address the coming challenges.

Seagrass refers to a group of monocotyledonous plants growing in marine environment, which perform great ecological functions and hold obvious economic values. In recent years, the global seagrass area has been decreasing significantly. How to repair seagrass beds quickly has evolving as a researching hotspot. At present, the methods of seagrass bed restoration, such as transplantation, seed planting and habitat improvement, hold both advantages and disadvantages. In contrast, tissue culture technology of seagrasses has advantages including fast propagation, large yield and low cost, showing great potentials for seagrass bed restoration. In this paper, we summarized the advances in the tissue culture of seagrasses at home and abroad in recent years, analyzed its success and failure factors and main problems, and put forward the corresponding solutions.

The study adopts the bibliometric methodology to investigate the scientific and technological literatures produced by six marine-related universities with the title“ocean university”(i.e., Guangdong Ocean University, Ocean University of China, Dalian Ocean University, Shanghai Ocean University, Zhejiang Ocean University and Jiangsu Ocean University), and conducts an in-depth and systematic analysis from six dimensions, namely, literatures publication time, collaborative country/region, collaborative research institutes, discipline (research direction), major journals, and highly cited literatures. The study found that the basic scientific research implemented by China's marine universities is becoming increasingly active, and the Ocean University of China plays a leading role in terms of the number and quality of published papers. The frequency of collaboration between China's marine universities and foreign institutions was low, and the Chinese Academy of Sciences was the preferred institution for China's marine universities when implementing domestic collaboration. Disciplinary research implemented by each marine university was widely distributed. Except for Jiangsu Ocean University, the discipline development in other marine universities was relatively balanced, and their scientific and technological papers were largely published in journals of JCR Quarter I. This study contributes to comprehensively grasping the basic scientific research status of China's marine universities, and to objective evaluation of their critical role in the context of today′s building an ocean power, therefor having great theoretical value and practical implication.

Year 2022 is a key for the full development of rural revitalization. Trying our best in agricultural and rural works is special and important. The development of leisure fisheries should aid to implementing the national rural revitalization strategy. In this study, we reviewed the developmental process, current situation and existing problems of leisure fishery, and put forward corresponding suggestions. The developmental process of leisure fishery in China can be roughly divided into three stages, the embryonic developmental stage from 1985 to 2002, the rapid developmental stage from 2003 to 2015 and the standardized developmental stage since 2016. The contribution of China′s leisure fishery to the fishery economy is steadily increasing; however, such contribution is relatively limited. The overall developmental level is not high, and the regional difference is significant. Biological resource and socio-economic systems are found to be the basic obstacles affecting the development of leisure fishery in China while the management and consumer systems are the main obstacles restricting further improvement. In order to promote the high-quality development of leisure fishery, suggestions are put forward, which include all-round, green and scientific developments, three aspects in total. To realize the all-round development of leisure fishery, the national development plan of leisure fishery should be formulated, the personnel management should be strengthened and the quality of practitioners should be improved. Simultaneously, the policy supervision and incentive mechanism of leisure fishery should be established. To realize the green development of leisure fishery, the leisure fishery industry standards and regulations should be formulated, the leisure fishery monitoring system and establish database should be improved, and improve the fishery resource evaluation and protection should be carried out. To realize the scientific development of leisure fishery, the discipline construction and academic research of leisure fishery and strengthen the popularization and application of science and technology should be strengthened. In future, the development of China′s recreational fishery may face both the policy and market driving forces brought about by the full implementation of the rural revitalization strategy and the great opportunity of cracking the problem of the transformation of the industry in the ten years of the Yangtze River. It may also face the challenge of the steady development of the leisure fishery industry and the adjustment of industrial structure under the impact of COVID-19.