Efficiency Measurement and Determinant Factors of Marine Economy in China: Based on the Belt and Road Perspective

School of Economics and Management, Nantong University, Nantong 226019, Jiangsu, China Jiangsu Yangtze Economic Belt Research Institute, Nantong 226019, Jiangsu, China School of Humanities and Arts, Jiangsu Shipping College, Nantong 226010, Jiangsu, China Department of Construction Engineering and Management, North China University of Water Resources and Electric Power, Zhengzhou 450046, China Statistics School, Southwestern University of Finance and Economics, Chengdu 611130, China


Introduction
e eastern coast of China carries 40% of the population with 13% of the land area and creates more than 65% of the GDP. However, the gross marine economic output accounts for only 9% of GDP, which shows a significant gap compared with 15% of GDP, the highest marine economy among the world marine powers.
In response to changes in the global situation, taking into account the strategic direction of land and sea and coordinating the overall international and domestic situation, China proposed the Belt and Road Initiative in 2013. In 2017, the national policy emphasized on focusing on the construction of the Belt and Road, insisting on both importing and exporting, forming an open pattern of landsea domestic and foreign linkages and east-west mutual assistance, and setting the new requirements and a higher starting point for the development of the marine economy in coastal areas. In 2019, China proposed at the Second Belt and Road International Cooperation Summit Forum that the promotion of the Belt and Road Initiative is inseparable from the construction of a global connectivity partnership. It can be seen that the Belt and Road Initiative has brought China the dual opportunities of a large international land channel as well as a large maritime transportation channel, which provided China with strong support for accelerating the development of the marine economy in coastal areas. As a "great bridge" for the Chinese economy to the world, the marine economy is an important part of the coastal economy, and its position in national development strategy has steadily improved. It is becoming a new growth point for Chinese economic development.
However, the rapid development of the marine economy has inevitably increased people's intervention in the ocean, and marine resources, environment, and ecology have been severely damaged. Under the background of the new normal of the marine economy, there is a need for scientific and quantitative research on the efficiency of the marine economy, exploring the ineffective links of its marine efficiency and seeking effective ways to improve the quality of marine economic development, in order to strengthen the Chinese marine economy and maritime power construction. erefore, in the context of the significant imbalance between the input and output of marine production factors, starting from the role of the Belt and Road Initiative on the marine economy, there is a need to accurately grasp the key influencing factors of the changes in marine economic efficiency and analyze the direction and extent of their influence. It is of great significance for improving the quality of marine economic development, speeding up achieving the strategic goal of maritime power, and ensuring the smooth implementation of the Belt and Road Initiative.
is study intends to select a super-efficiency Slacks-Based Measure (SBM) model to measure marine economic efficiency and analyze its temporal and spatial pattern evolution characteristics. Based on the influence mechanism of the Belt and Road on marine economic efficiency, a marine economic efficiency impact index system is established to analyze the factors influencing efficiency and contributing causes by application of the Bayesian model averaging (BMA) approach. It aims to provide a theoretical basis to identify the influencing factors of marine economic efficiency, improve the construction of the Belt and Road, and realize the high-quality development of the marine economy.

e Belt and Road and the Marine Economy.
Since the Belt and Road was put forward, it has had a significant impact on the Chinese national economy from many aspects. Studies have found that the political connection of leaders can affect the infrastructure investment, industrial structure changes, and economic growth of the source or related regions through the implementation of fiscal, monetary, financial, and foreign trade policies [1,2]. e improvement of transportation infrastructure and traffic density along the New Silk Road economic belt will help play a positive role in promoting trade and boost the integrated development of the regional economy [3]. e strong cooperation with the infrastructure construction of the countries along the Belt and Road can effectively promote the reconstruction of the global value chain [4]. e smooth implementation of the Belt and Road Initiative will not only promote the overall balance of the Chinese eastern, central, and western regions of the economy but also provide a diversified medium of cooperation for facilitating and liberalizing the world economy and trade [5]. It can strengthen appropriate trade policy communication with countries along the route and enhance the stability of bilateral trade settlement. e initiative will help China and the countries along the route to jointly construct a mutually beneficial and win-win trade growth pattern and effectively promote economic cooperation among the countries along the route [6]. From the current point of view, the intensive marginal expansion has shown a significant promotion effect on the investment of the Belt and Road Initiative [7]. e leading role of finance in the Belt and Road Initiative must be fully exerted. Attention must be paid to improving the efficiency and quality of finance in countries along the route and deepening the financial cooperation between China and countries along the route [8]. It can be seen that the Belt and Road construction has laid a solid foundation for regional economic development to shift from quantity growth to quality improvement.
With the development of research, scholars have introduced relevant theories about the impact of the Belt and Road Initiative on economic development in the marine field and researched the impact of the Belt and Road Initiative on the marine economy. It was pointed out that the Belt and Road, as China caters to the deepening of reform and opening-up, advocated the reconstruction of ocean awareness and encourages people to actively develop and utilize the ocean and breakthrough geographical barriers to walk into the world economic network [9].
It was emphasized that the implementation of the Belt and Road Initiative was a manifestation of the arrival of the land-sea economy era and provides an essential platform for China and countries along the route to carry out blue economic cooperation and construct "blue partnership" [10]. Some other scholars pointed out that the Belt and Road is intended to adhere to land-sea coordination and mutual benefit, and the key to its smooth implementation lies in the promotion of the status and role of the marine economy [11]. e Belt and Road is applied to develop the marine economy and achieve land-sea overall planning which is the core means of Chinese progressive geostrategic [12]. By analyzing the economic development of coastal node cities and the coordinated development of port and city, it is found that, after removing the influence of common trends and impacts, the net effect of the policy of the Belt and Road is negative [13]. e expansion of development levels, transportation infrastructure construction, and optimization and upgrading of the marine industry structure are the main aspects of marine economy development under the Belt and Road [14]. It can be seen that the continuous advancement of the Belt and Road initiative is conducive to the maritime economic cooperation between China and countries or regions along the route. e continuous strengthening of maritime economic cooperation between countries has also pointed out the direction for China to better plan the construction of the Belt and Road and then attract more maritime countries to participate.

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Discrete Dynamics in Nature and Society

Marine Economic Efficiency.
e intensity of marine resource consumption and the pressure on the marine ecological environment continue to increase, which has seriously affected the output benefits of marine production factors [15]. eories of economic efficiency are gradually introduced into the marine field. Evaluation methods mainly include DEA, SFA, SBM, and Malmquist. e research content mainly focuses on the efficiency of single marine industry and the overall efficiency of the marine economy.
At the efficiency level of the single marine industry, it was found that the growth rate of comprehensive technical efficiency of the fishery industry was significantly lower than that of fishery GDP and was mainly contributed by scale efficiency [16,17]. rough methods such as the transformation of production and output constraints, it can effectively improve scale efficiency and increase the output efficiency of marine fisheries. Some scholars have gradually extended the efficiency theory to industries such as marine transportation, marine shipping, and coastal tourism. Talley [18] and Pablo et al. [19] analyzed the economic efficiency of ports and found that there is a negative relationship between port scale and economic efficiency. Pang [20] and Sun and Xiao [21] further found that the key to reducing port scale efficiency was caused by redundant input and low output efficiency. Yu and Pan [22] and Zhou and Guan [23] analyzed the efficiency values of the marine transportation industry, marine shipping industry, and coastal tourism and found that pure technical inefficiency was a reduction in overall technical efficiency, which is the direct cause that leads to regional differences. e research results on the overall efficiency of the marine economy are mostly domestic. Scholars mainly combined their research themes and used models such as data envelopment analysis (DEA) and SBM to select marine employees, marine capital stock, port cargo throughput, etc., as input variables, and the added value of the marine economy as output variables. e efficiency is measured and calculated to obtain the changing rules of efficiency accurately. Marine industrial structure, resource environment, science and technology, and regional openness are the key to the formation of marine economic efficiency [24][25][26]. Due to the in-depth research, some scholars classified environmental factors into the evaluation system of marine economic efficiency. e green efficiency and ecological efficiency of the marine economy became research hotspots [27,28].
By sorting out the existing literature, it is found that the research on the development of the marine economy by the Belt and Road is also relatively wealthy, but further improvement is needed in the following two aspects. On the one hand, the research on the impact of the Belt and Road Initiative on marine economic efficiency is blank. On the other hand, the efficiency-influencing factors selected by different scholars are different, and the conclusions drawn by different analytical frameworks are quite biased and lack specific theoretical support. e review of existing literature found that scholars are relatively mature in the research on the influencing factors of marine economic efficiency and affirmed the important impact of the Belt and Road on the development of the marine economy, and the research on the development of the marine economy in the context of the Belt and Road is relatively rich. But it was mainly concentrated on the impact of the Belt and Road on the regional economy and marine economic efficiency. ere were few studies on the impact of the Belt and Road Initiative on the efficiency of the marine economy.
Given this, this study applies the super-efficiency SBM model to measure the marine economic efficiency of coastal provinces and uses time series and standard deviation ellipses to analyze the characteristics of temporal and spatial patterns. A marine economy efficiency impact index system is constructed based on the relationship between the Belt and Road and marine economic efficiency. e research not only provides a theoretical basis for choosing a suitable coastal area marine economic development model, formulating macroeconomic policies for the marine economy, and promoting the construction of the marine economy but also pointing out the direction for coastal areas to use the Belt and Road Initiative to achieve high-quality marine economic development goals.

eoretical Framework.
e construction of the Belt and Road will promote the all-round development strategy of countries along the route, promote the free flow and optimal allocation of production factors such as talents, technology, and capital, improve the output efficiency of factors, and improve the quality of economic development. Marine economic efficiency is a measure of the ability of marine labor and capital to transform into the gross marine product and an essential manifestation of the output benefits of production factors.
e Belt and Road Initiative brings significant opportunities to the eastern region. It is necessary for coastal areas to establish the relationship between the Belt and Road construction and marine economic efficiency from multiple perspectives such as industry, transportation, trade, technology, and environment to seek a double-win cooperation path. e specific relationship is shown in Figure 1. e detailed description is as follows.
(1) With the continuous advancement of the Belt and Road construction, the "One Road" regional development platform will be completed, and the regional integrated development pattern of the coastal marine economy will gradually be shaped [11]. e advantages of the marine industry foundation, labor force, and market in the eastern region will be highlighted. ey promote the upgrading and transformation of the marine industry structure, thereby realizing reasonable allocation of marine production factors and improving the output efficiency of the marine economy.
(2) e key to constructing the Belt and Road lies in constructing infrastructure such as aviation, highspeed rail, and ports [13]. It is necessary to build a comprehensive transportation network as a guide, Discrete Dynamics in Nature and Society plan the interconnection layout of the countries along the route, and form a diversified, multilevel international cooperation channel. e network will deepen international cooperation in transportation, promote the facilitation of investment and trade, and maximize the social welfare of humankind. (3) Trade opening-up and investment opening-up are the two main aspects of opening to the outside world. e promotion of the Belt and Road strategy will not only help open up the logistics, trade, and investment channels between the eastern region and southeast Asia but also accelerate the exploration of open economic development. e pace of system reform also laid the foundation for Chinese participation in the future development model of economic globalization and international division of labor [7]. (4) Relying on the major strategic opportunities of the Belt and Road, China will actively cooperate with countries along the route to build marine science and technology parks and jointly cultivate high-tech marine science and technology talents, gradually establishing a stable long-term partnership [9]. China would take advantage of the favorable conditions for international exchange and cooperation of marine science and technology and give full play to marine science and technology to the marine economy. (5) e intensity of marine environmental protection and marine pollution control and the rational use of marine resources are the prerequisites for transforming the marine economy to quality and efficiency. e concept of the 21 st Century Maritime Silk Road emphasizes the green development path and promotes organic integration with the construction of marine ecological civilization [10]. e Chinese government proposes to participate in the global marine ecological environment governance system actively and jointly implement marine ecological environmental protection actions with countries along the route. It will provide high-quality marine ecological services, ensure the ecological safety of global oceans, and reduce the marine economy's undesired output through strong ecological constraints.

Super Efficiency SBM Model.
e DEA model is a commonly used method for efficiency estimation. Its basic idea is to obtain more output with minimal input. It is mainly measured from radial and angular perspectives.
ere is no need for the preset production function. It can effectively avoid the bias of function form setting. Due to insufficient consideration of the slackness of input and output, the accuracy of the measured efficiency value is insufficient. Tone proposed the SBM model in 2001, which effectively solved the traditional DEA model [29]. e model made the efficiency value conform to the strictly monotonous decreasing law by changing the level of relaxation. Besides, the traditional DEA model analysis method will cause multiple decision-making units to be useful simultaneously, and the resulting efficiency values are not greater than 1, while the effective decision-making units on the frontier are all at 1. It is difficult to distinguish further and the problem of sorting. Andersen and Petersen proposed a super-efficiency DEA model in 1993 [30]. e core idea is to remove the evaluated decision-making unit from the reference set. e efficiency value of the invalid decisionmaking unit remains unchanged, and the efficiency value of the effective decision-making unit refers to other decisionmaking units. e efficiency of the composition is obtained along the surface, which effectively solves the problem of  sorting the efficiency values of the traditional DEA model. Tone combined the SBM model and super-efficiency DEA model to construct a super-efficiency SBM model [31], distinguishing effective decision-making units based on slack variables.

Bayesian Model Averaging Method.
In 1978, the Bayesian model averaging (BMA) method was an effective method to solve model uncertainty [32]. An average model is obtained mainly by setting prior information and probability of explanatory variables, and it calculates the posterior inclusion probability of potential explanatory variables with the assistance of relevant information of the dataset to judge the relative importance of each explanatory variable. e details are as follows.
Consider the general multiple linear regression model In the model, y is the marine economic efficiency, x is the explanatory variable set that affects marine economic efficiency, k is the number of explanatory variables, α is the constant, β is the coefficient, and ε is the error term ε ∼ N(0, σ 2 ). If M � M 1 , M 2 , . . . , M N } is a model space that is arbitrarily constructed by k explanatory variables, there are models of N � 2 k . e BMA method is employed to estimate each model to obtain the posterior probability and statistical coefficient indicators of each explanatory variable and mark M j as one model in M, and the prior probability of M j is P(M j ), and based on Bayesian theory, calculate the posterior probability of the model M j : In the above formula, X is a matrix of explanatory variables of k, and j � 1, 2, . . . , N. It can be seen that the weighted average of the prior probability of the model is the posterior probability of the model. So the relevant statistical indicators of regression coefficients of each explanatory variable can be obtained [33], including posterior inclusion probability (PIP), posterior mean (PM), and posterior variance (PV). Among them, the value of PIP indicates the relative importance of each explanatory variable, the sign of the PM value reflects the direction of action of the explanatory variable, and the absolute number of the ratio of PM to posterior standard deviation reflects the explanatory ability of the explanatory variable. Besides, it should be emphasized that different models, prior parameter probabilities, and model space sampling methods will all affect the final result of BMA estimation.

Data Source and Variable Description.
e research takes the panel data from 11 provinces along the coast of China between 2006 and 2017 as the research object. e data involved are drawn from the Chinese Marine Statistical Yearbook, Chinese Statistical Yearbook, and Statistical Yearbooks of coastal areas.

Selection of Variables for Ocean Economic Efficiency Measurement.
(1) Input variables: comprehensively, considering the availability and scalability of the data and referring to the research by Wang  Ocean Product (GOP) is a total indicator that reflects the level of regional marine economic development.
Referring to the practice of Ji and Wang [36], the added value of marine economy in coastal provinces is applied as the output variable in the super-efficiency SBM model, and the constant price in 2006 is adopted to deflate it to remove the effect of price factors.

Selection of Influencing Factors for Marine Economic
Efficiency. Based on the analysis of the mechanism of the Belt and Road Initiative on the efficiency of the marine economy, the influencing factors of the marine economy under the Belt and Road Initiative are selected in line with the principles of scientificity, operability, and comparability of the evaluation indicators (see Table 1).
(1) Marine industry structure: based on the research by [37,38], the rationalization, diversification, and advancement of the marine industrial structure are selected to reflect the optimization of the industrial structure. Among them, rationalization is obtained by quantifying the proportion of each industry as an entropy coefficient, diversification is obtained by the weighted average of the proportions of the tertiary industry, and advancement is obtained by the ratio of the added value of marine tertiary and secondary industries.
Discrete Dynamics in Nature and Society (2) Transportation integration: combined with the research of [3,4], the density of transportation network and investment are selected to determine the spacetime cost of transportation and the utilization of regional industrial advantages, reflecting the development of integrated transportation. Among them, the density of the transportation network is obtained by the weighted average of the density of roads, railways, inland rivers, and aviation, and the scale of transportation investment is measured by the proportion of transportation expenditures in public financial expenditures. (3) e level of opening-up: based on the research by Pei [39], trade opening and investment development are selected to reflect the level of opening-up. Trade opening is measured by the proportion of total import and export trade in GDP. Investment opening selects foreign direct investment as a percentage of GDP. e proportion is measured. (4) Marine science and technology: based on the research of [40,41], indicators such as the conversion rate of marine scientific and technological achievements, the reserve of high-level talents, the density of scientific research institutions, and the level of scientific and technological innovation are selected to reflect the development of marine science and technology. e innovation level of marine science and technology here is calculated by the weighted average of the number of topics, patents, and articles undertaken by marine science and technology institutions, and the reserve of marine high-level talents is measured by the proportion of marine postgraduates in school. (5) Marine ecological environment: more than 80% of total marine pollution in China comes from the land. Industrial wastewater that does not meet the set standards or industrial solid waste that has not been effectively treated is the source of sea pollution.
Concerning the practices of [27,42], the rate of compliance of industrial wastewater discharge and the rate of comprehensive utilization of solid waste were selected to measure marine ecological environmental protection.

Time Characteristics of Marine Economic Efficiency.
With the assistance of MaxDEA software, a variable return to scale, nonoriented super-efficiency SBM model is selected to calculate the marine economic efficiency values of 11 coastal provinces in China between 2006 and 2017, and the change trends of efficiency across the country and provinces are plotted, as shown in Figure 2.
It is easy to see that the national average of marine economic efficiency has not changed much between 2006 and 2017, and they are all on an effective frontier. From the perspective of the changes in the marine economic efficiency of the province, Tianjin and Jiangsu have become highly efficient in 2008 and 2009, respectively, after the low efficiency in the initial years. e efficiency value of Fujian Province has shown high efficiency since 2014. Zhejiang Province has always been in a state of low efficiency, and the efficiency values of other regions have always been on an effective frontier. e reason is that, from 2006 to 2008, China actively advocated the construction of a "resourcesaving and environment-friendly" society, and the eastern coastal areas successively introduced relevant measures for energy saving and emission reduction. However, the exportoriented marine economy was hit by a financial crisis that suffered strong impact, by which the intensive effect of marine economic development has been hindered.
From 2009 to 2012, China was transitioning from the "Eleventh Five-Year" period to the "Twelfth Five-Year" period.
e "National Science and Technology Support Plan," "863," and "973" plans were launched one after another. e scale effect and supporting the capacity of marine science and technology have been releasing continuously. "Transformation and structural adjustment" has become the focus of marine economic growth. However, the foam effect caused by mandatory investment in the marine industry, while accelerating the optimization and upgrading of the marine industry, harms marine resources and ecological environment, which hindered the development of the  Coastal areas have regarded the marine economy as the focus of regional development, and three major marine economic circles have gradually formed. e radiation-influencing effect of the economy on coastal and hinterland has become increasingly prominent. It should be noted that the previous "reclamation of sea and land" project has caused severe damage to marine resources and the ecological environment and has a certain negative effect on marine economic efficiency during this period.

Spatial
Features. ArcGIS 10.5 software is used to calculate the basic parameters of the standard deviation ellipse of marine economic efficiency in coastal provinces from 2006 to 2017. e spatial pattern characteristics of marine economic efficiency are analyzed in terms of center of gravity, scope, shape, and direction.
From the changes in the center of gravity in Figures 3  and 4, from 2006 to 2017, except for a few years, the overall marine economic efficiency gradually moved from northeast to southwest with overall movement of 142.6 km. It showed an east-west movement of 83.9 km and a north-south movement of 97.34 km. Among them, during 2006-2010 and 2013-2014, it mainly moved to the southwest. During 2014-2017, it moved south, indicating that the output efficiency of marine production factors in the Yangtze River Delta and Pan-Pearl River Delta has been steadily improving. From the perspective of the range and shape changes in Figure 5(a), the overall spatial range of marine economic efficiency shows a shrinking trend. Compared with 2006, the range of efficiency distribution in 2017 decreased by about 4.07%, indicating that the growth rate of regional marine economic efficiency in the interior ellipse is significantly faster than that of the outer ellipse. e shape change is characterized by the degree of flatness, showing a changing trend of "increasing first and then decreasing." Among them, the flatness index dropped from 0.332 in 2006 to 0.318 in 2009. It then quickly increased to 0.349 in 2017, which shows that the efficiency value growth rate of the area distributed in the long axis direction of the ellipse is higher than that of the short axis direction. e higher efficiency growth rate in the Pan-Pearl River Delta region drives the efficiency standard deviation ellipse to expand southward. From the perspective of the change in the direction in Figure 5 e abovementioned spatial pattern changes are strongly related to geographic location, marine industrial structure, and policy environment. For example, Liaoning Province in Bohai Rim is relatively backward in terms of environmental protection and resource optimization, and its comprehensive utilization rate of industrial solid waste is only 38%. Hebei Province, dominated by mineral resources and steel industry, suffers severe marine resources and environmental problems. Shandong Province, where the fishery is the leading industry, consumes lots of marine biological resources, which has severely affected the marine economic efficiency of the Bohai Rim. e Yangtze River Delta region has benefited from better geographical location advantages and land economic foundation. With the continuous advancement of national strategies such as the Belt and Road and the Yangtze River Economic Belt, the development of the green marine economy has been significantly accelerated. e efficiency of the marine economy has been significantly improved. Fujian Province in the Pan-Pearl River Delta region has always had preferential policies given by the state and has an excellent marine economic foundation. During the Eleventh Five-Year Plan and Twelfth Five-Year Plan period, it pays more attention to the development of marine emerging industries and has good marine resources and environmental benefits. Hainan Province has abundant marine resources and is dominated by the "high-yield, low-polluting" marine tertiary industry. However, due to the impact of marine disasters and disputes of rights, efficiency improvement is slow. e improvement of marine economic efficiency in other regions Discrete Dynamics in Nature and Society such as Zhejiang and Guangdong has benefited from the superior marine industrial structure and the scale effect and technology-induced effect brought by the input of marine production factors such as the number of sea employees and marine capital stock.

Drivers of Marine Economic Efficiency.
Given the regional differences in natural resource endowments, land economic foundations, industrial development policies, and spatial interactions, the unbalanced development of the coastal marine economy is more prominent. e same explanatory variable produces a different-level impact on the efficiency of each regional marine economy. Concerning geographical locations of the South (including Fujian Province, Guangdong Province, Guangxi Zhuang Autonomous Region, and Hainan Province), Centre (including Shanghai, Jiangsu Province, and Zhejiang Province), and North (including Hebei Province, Liaoning Province, Tianjin City, and Shandong Province), the observation objects are divided into regions. From regional perspectives, the marine economy's efficiency is estimated by BMA to Regarding marine economic efficiency as the explained variable, the influencing factors mentioned above act as an explanatory variable, and a total of 16,384 candidate models are formed. e R software is used to call the BMS software package that integrates the BMA method and MC 3 sampling technology. In the premise of the model obeying random prior probability and hyperparameters, the BMA estimation results of the determinant factors of regional marine economic efficiency are obtained, as shown in Table 2.
(1) From the perspective of marine industry structure variables, the efficiency of the marine economy in the southern and central regions is hugely dependent on diversification, advancement, and rationalization of the marine industry structure and a strong positive effect. e northern region is strongly dependent on the diversification of the industrial structure. e proposal of the Belt and Road Initiative has fully released the advantages of marine resources, geographical location, and economic foundation of core coastal cities. It has a strong effect on improving the Discrete Dynamics in Nature and Society 9 efficiency of the marine economy. Further analysis found that, except for Guangdong and Shandong, other neighboring provinces with close GDPs have a small gap in marine economic GDP, but the industrial structure difference is noticeable. For example, Zhejiang and Fujian have a higher level of advanced industrial structure. e industrial structure has been formed earlier, making the southern and central regions have similar effects on the efficiency of the marine industrial structure. e northern region is overly dependent on the pull of marine primary and secondary industries, and the problem of overexploitation of marine resources is serious. e level of rationalization and advancement of the industrial structure is relatively backward, and the ability to explain efficiency is unobvious.
(2) From the perspective of transportation integration variables, the density of the transportation network promotes the efficiency of the three major regions to varying levels. e southern region has the most substantial dependence on the density of transportation network; the scale of transportation investment in the central region reflects strong explanatory ability (84.88%) and adverse effect (−0.311).
e reason for this is that most of the southern cities are located in Guangdong Province, where the intercity traffic correlation is relatively strong and the spatial spillover effect of the marine economy is more significant. Lianyungang and Yancheng in the middle and Cangzhou, Dandong, Binzhou, and other cities in the north have transportation infrastructure, and the level of its interconnection and interoperability is low. e regional transportation master plan still needs to be improved, resulting in a weaker influencing force for radiation from Tianjin and Shanghai. e Belt and Road Initiative has increased investment in transportation projects in coastal areas, especially the Yangtze River Delta and Guangdong. However, public finances cannot afford the long-term, highinvestment, and high-risk transportation infrastructure construction. Private participation in the investment and financing model gradually dominates. e substantial investment competitiveness of the central region is the main reason for its strong negative effect on marine economic efficiency.
(3) From the perspective of variables such as the level of opening to the outside world, the explanatory capacity of all variables on the efficiency of the marine economy in the central region is between 10% and 20%. e explanatory capacity and adverse effects of trade opening on the efficiency of the southern and northern regions are more significant. e explanatory capacity of foreign direct investment in the northern region is relatively strong. e explanatory capacity of foreign direct investment in the southern and northern regions is between 60% and 70%. In the early stage of reform and opening-up, foreign investment in China was mostly concentrated on the southeast coast. With the development of Pudong, the policy advantages enjoyed by the Pearl River Delta gradually disappeared, and the foreign direct investment performance index in coastal areas gradually declined. e central region thoroughly enjoyed the dividends brought by Shanghai constructing an international economic, trade, financial, and shipping center. e past export experience will help increase eastern coastal area investment in countries along the Belt and Road. Besides, the Chinese economic structure and growth model have inherent shortcomings, making the development of the marine industry not keep pace with the level of trade and investment, leading to traditional industries dominating the foreign investment industry. e degree of integration with the world economy still needs to be improved. us, the positive effect of marine economic efficiency needs to be further explored. (4) From the perspective of marine science and technology variables, the southern marine scientific and technological innovation level and high-level talent reserves have a substantial impact on marine economic efficiency. e central and northern parts are similar, and all variables have less than 30% explanatory capacity for marine economic efficiency. e reason is that the layout of Chinese marine scientific research institutions is characterized by the spatial pattern of the North being more important than the South. Since the Belt and Road Initiative was put forward, China has paid more attention to the growth of the total marine economy in the short term, which has led the marine industry sector to commit to scaling expansion. More than half of the institutions engaged in marine basic scientific research are different from the actual needs of the regional marine industry. Among them, the southern region is more obviously driven by the radiation of central cities such as Shanghai and Guangzhou, enjoying a higher level of marine technology and a complete platform for transforming scientific and technological achievements, and most regions have high technical efficiency. e cities such as Tangshan, Qinhuangdao, Qinhuangdao, Panjin, and Yancheng in the central and northern regions lack government support and intervention.
e lack of investment in scientific research and innovation motivation weakened the marine technology spillover effect in core cities, and the overall technical efficiency level was not prominent. (5) From the perspective of marine ecological environment variables, the industrial wastewater discharge compliance rate has a strong explanatory capacity and negative effect on the marine economic efficiency of the three major regions. e comprehensive utilization rate of industrial solid waste has a high explanatory capacity of 99.67% for the efficiency of the southern region. e northern and central regions do not exceed 20%, and both show adverse effects.
e Belt and Road construction has promoted the rapid development of the coastal industrial economy. Although the growth rate of industrial wastewater and solid waste discharge in various regions has been declining year by year, but affected by the environmental governance model of the heavy end, light source, and weak cycle, land-source sewage is discharged into the sea. e phenomenon of excessive discharge and substandard monitoring has become severe, and nearly 40% of solid waste cannot be effectively used. For example, the discharge of industrial wastewater and solid waste per GOP in Liaoning, Hebei, Jiangsu, Guangxi, and other places has been above average. e total solid waste utilization rate in Hebei, Guangxi, Hainan, and Fujian is less than 80%.
e Pearl River Delta region with better industrial bases actively introduces advanced foreign capital technology and management to promote industries with high technological content and low environmental pollution.
It can be seen that, during the study period, the industrial wastewater discharge compliance rate and the PIP of the marine industrial structure diversification were both greater than 77%, and the corresponding absolute numbers of the posterior mean and standard deviation ratios were both greater than 1.1. Both have the strong explanatory capacity in marine economic efficiency. Further analysis of the variables that have a strong negative effect on the efficiency value found that the southern region needs to tap the potential of the transformation rate of marine scientific and technological achievements and the density of marine scientific research institutions. e central region needs to pay attention to the impact of the marine high-level talent pool. e northern region needs to focus on stimulating the effect of the marine tertiary industry on the marine economy.

Conclusions and Recommendations
is study takes the panel data of 11 coastal provinces in China as a sample between 2006 and 2017. It applies the super-efficiency SBM model to measure the marine economic efficiency and analyzes its temporal and spatial pattern evolutionary characteristics. en, the marine economic efficiency-influencing indicator system is established based on the impact of the Belt and Road mechanism on marine economic efficiency. At last, it adopts the BMA method to analyze efficiency-influencing factors and causes. It provides a theoretical basis for advancing the construction of the Belt and Road and achieving the goal of high-quality marine economic development, also it provides advice on promoting marine economic efficiency in coastal areas, choosing appropriate development models, and formulating macroeconomic policies for the marine economy. e results show the following: (1) e average change of the national marine economic efficiency during the observation period is not large. e efficiency values of most provinces are relatively stable.
e overall efficiency center of gravity is gradually shifting from the northeast to southwest, and the spatial scope was in shrinking trends. e flatness level shows "increase at first followed by decrease," and the direction angle indicates a fluctuating trend.
(2) e compliance rate of industrial wastewater discharge and the diversification of the marine industry structure have a robust explanatory capacity in marine economic efficiency in the three major regions. e southern region needs to tap the potential of the transformation rate of marine scientific and technological achievements and the density of marine scientific research institutions. e central region needs to pay attention to the role of the marine high-level talent pool. e northern region needs to Discrete Dynamics in Nature and Society focus on the role of the marine tertiary industry in pulling the marine economy.
In specific practice, it is necessary to start from various factors that affect the efficiency of the marine economy and combine the level of impact and the direction of action to comprehensively improve the quality of marine economic development. e specific approaches are as follows: (1) Facilitating the optimization of the marine industry structure: based on the characteristics of rationalization, diversification, and advanced nation of the marine industrial structure of each province, appropriate marine industry development goals will be formulated. With the development trend of the world's marine fisheries, the marine aquaculture industry should be developed to reduce the contribution of traditional marine fisheries to marine economic growth. With the progressing of technology and achievement transformation of the marine industry, the marine industry would be built with strong brands and excellent technology, to improve the added value and efficiency of the marine secondary, grasp the "service" function of the marine tertiary industry, scientifically determine the development scale of the marine tertiary industry, and avoid blindly pursuing the increase in the value of the industrial proportion. For example, for Tianjin, Shanghai, and Guangdong, there is a need to break the trend of centralized development of a single marine industry; for Liaoning, Shandong, Jiangsu, Zhejiang, and Fujian, there is a need to focus on the diversified development of marine industries, and for Hebei and Guangxi, there is a need to focus on increasing marine labor productivity. (2) Strengthening the construction of integrated transportation: based on the Belt and Road policy guarantee function, there is a need to fully release the advantages in the prioritized areas of facility connectivity, attach importance to the investment and construction of transportation infrastructure, accelerate the realization of international interconnection in the transportation field of coastal areas, and enhance the radiation and driving capacity of the marine industry to achieve marine production factors to effectively flow around the world. Regarding the transportation industry as the basic industry and tourism and port industry as advantageous industries, gradually build the eastern port industry cluster, resource development industry belt, and tourism industry belt to strengthen the dominant position of the marine industry. For example, for the coastal areas of Liaoning, Hebei, and Jiangsu, there is a must to continuously improve the overall transportation planning, increase investment, fully play the leading role of the surrounding areas with higher accessibility, and strive to improve the connectivity of the eastern coastal transportation infrastructure. (3) Improving the opening-up level of the marine economy: in order to promote the construction of the Belt and Road as the top-level design of China's economic diplomacy and a key guideline for opening-up, we should focus on alleviating the shortage of land resources, breaking through resource bottlenecks, and expanding development space. We should also make full use of the advantages of coasts opening to the outside world and absorb optimized allocation methods for marine economic production factors and advanced ocean management concepts from other countries or regions. Under the new development pattern of "circulation," we should match the cooperation for the double win with the essential connotation of "opening," take the matching and reform of both supply and demand sides as the starting point to cater to the market demand for marine high-tech and high value-added market, and change the traditional labor-intensive, primary product marine industry supply model. Besides, we also need to optimize the structure of marine foreign trade and cultivate new momentum for marine trade, continue to enhance the status of maritime foreign trade in services, and finally achieve the purpose of enhancing the positive impact of opening-up on the growth of marine economic efficiency. (4) Promoting the progress of marine science and technology: combined with the short-, medium-, and long-term development plan of marine science and technology, we should allocate the national marine science and technology resources scientifically, improve the unreasonable layout of marine scientific research institutions, and pay attention to the problems of obvious regional advantages and weak scientific research force. e coastal regions should be encouraged to strengthen human capital investment, improve the induction system of high-level marine talents, train high-quality marine scientific and technological personnel, enhance the cooperation between "politics, industry, university, and research" in coastal cities, which aims to change the current unitary marine technological research and developmental model, encourage enterprises and universities or scientific research institutions to jointly establish marine technology research and development centers, and share scientific and technological patent dividends employing capital or technology shares. Also, it needs to fully exert the radiative and driving function of the three major coastal city clusters, relies on the flow of talents and technology transfer, promotes the effective application of marine scientific and technological resources, improves the efficiency of the marine economy, and builds the eastern coastal zone full of modern science and technology vitality.
(5) Contributing to the improvement of the marine ecological environment: it is advocated to use the Belt and Road to strengthen marine cooperation with other countries in the field of marine environmental protection and restoration, marine endangered species protection, marine environmental pollution prevention, marine acidification, etc., adhere to the principle of "jointly protecting and avoiding largescale development" to formulate a sustainable marine development strategy from the overall situation, strengthen the development of marine economic management and planning, and ensure the coordinated development of marine economy, society, and ecology with the "large-scale, paid, and orderly" marine industry. We should also need to establish a land-sea linkage pollution prevention mechanism to strictly control the increase in pollution sources and improve the ecological carrying capacity of shorelines and beaches. Besides, there is a need to participate in global marine environmental governance action actively, relying on the idea of systematic governance and multiple forces to improve the efficiency of marine ecological environment governance and force the efficient development of marine resources through ecological environmental constraints and promote the marine economy to take quality and benefit-oriented development path.

Data Availability
e data used to support the findings of this study are available from the corresponding author upon request.

Conflicts of Interest
e authors declare that there are no conflicts of interest regarding the publication of this paper.