Analysis of Regional Differences and Convergence of Equalization Level of Marine Public Services in China’s Coastal Areas

Abstract

The equalization of marine public services is an effective way to achieve harmonious coexistence of the sea. In this paper, a variable fuzzy recognition model is used to measure the equalization level of marine public services in 11 provinces and cities in China’s coastal areas from 2006 to 2019. The Dagum Gini coefficient, kernel density estimation model, and convergence model are used to study their regional differences, distribution dynamics, and convergence characteristics. The results show that the equalization level of marine public services in China’s coastal areas increased year by year from 2006 to 2019. In terms of spatial distribution, the equalization level of marine public services in coastal areas presents an unbalanced distribution pattern. The overall regional differences in the equalization level of marine public services in China’s coastal areas have narrowed, and the inter-regional differences are the main reasons for the overall differences. The absolute difference in the equalization level of marine public services in China’s coastal areas shows an expanding trend. The equalization level of marine public services in China’s coastal areas has α convergence and β convergence.

1. Introduction

Despite the challenges posed by the COVID-19 pandemic and a complex global economic landscape, China’s marine economy has exhibited steady growth. According to the Statistical Bulletin of China’s Marine Economy, in 2021, China’s marine GDP surpassed 9 trillion yuan for the first time, representing 8% of the national GDP and 15% of the GDP in coastal regions [1]. Consequently, the marine economy has emerged as a new driver of national economic development. To facilitate stable growth within this sector, it is imperative for the government to fulfill its fundamental responsibilities regarding marine public services. This includes optimizing resource allocation and enhancing utilization rates through improvements to public service platforms and establishing a comprehensive marine public service system aimed at promoting economic expansion in this domain. However, disparities in supply levels of marine public services have resulted in variations in infrastructure quality, industry informatization, and ecological conditions across different coastal areas—factors that hinder high-quality development within the marine economy. In formulating China’s 14th Five-Year Plan for National Economic and Social Development, central authorities emphasized ongoing efforts toward equalizing basic public services. As part of this strategic initiative, achieving equality in these services plays a crucial role in fostering coordinated development among coastal regions’ marine public services while addressing regional imbalances that affect overall economic progress. Therefore, investigating equitable access to marine public services along coastlines is vital; understanding discrepancies will aid efforts to rectify uneven developments and achieve high-quality advancement within China’s maritime economy.

Research on international models for equalizing public services predominantly centers around health systems [2], education frameworks [3], and various ethnic groups [4,5]. With an increasing focus on equitable access principles since their introduction into policy discourse in China, research fields concerning equalization have diversified significantly over time. Current studies primarily address urban–rural divides [6], educational equity [7], healthcare accessibility [8], and cultural inclusivity [9]. The scope ranges from national analyses [10] down to urban agglomerations [11], as well as provincial-level assessments [12] extending even further into county-specific investigations [13]. Notably emerging are considerations surrounding migrant workers’ rights to equitable access [14] alongside those pertaining to transient populations [15].

Although the research on equalization of public service is increasingly abundant, there are few studies in the marine field. The studies of marine public service mainly focus on the following aspects: (1) Definition of connotation. Zhang [16] defined the connotation of marine public service based on the new public service theory, and Ye [17] defined marine public service based on the concept value that all people share the fruits of marine development. However, due to the complexity of marine systems, the connotation of marine public service should be more abundant. (2) Horizontal measurement. Wu et al. [18] constructed an evaluation index system for the supply level of marine public services from five aspects: marine production services, marine public management, marine science and technology services, marine environmental protection, and marine economic and social development, and concluded that the supply capacity of marine public services in coastal areas should be improved in the aspects of marine production services and marine economic and social development [19]. As China’s economy enters a new era of high-speed development to medium-high-speed development, the new development concept requires marine public services to provide services from a multi-dimensional perspective, and the existing evaluation index system lacks the perspective of informatization and green development. (3) Lifting path. Zhang et al. [19] took Shanghai as an example to analyze the strategic positioning of Shanghai’s marine public service from four perspectives: international, regional, public service, and industrial positioning, and proposed that marine public services should be developed jointly with all sectors of society. Most of the existing literature has put forward countermeasures and suggestions from the macro level, and there is a lack of research and analysis on the promotion path at the micro level.

Based on this, in order to further improve the relevant research on equalization of marine public services, this paper makes supplements in terms of the following aspects: (1) Further enrich the connotation of equalization of marine public services according to the theory of marine economic system. (2) Add public information, cultural development, and environmental governance indicators to the marine public services equalization evaluation system, and use the variable fuzzy recognition model to measure and analyze the marine public services equalization level of 11 provinces and cities in China’s coastal areas from 2006 to 2019. (3) Use the Dagum Gini coefficient, kernel density estimation, and convergence model to study the regional differences, distribution dynamics, and convergence characteristics of the equalization level of marine public services in China. Then, according to the causes of regional differences and convergence characteristics, propose countermeasures and suggestions in order to achieve the overall improvement in the equalization level of marine public services in China and help the coordinated development of the marine economy in coastal areas. The marginal contributions of this paper are as follows: First, at the theoretical level, this paper combines the theory of marine economic systems with the equalization of public services, expands the theoretical boundary of the equalization of marine public services, and provides a new perspective and ideas for subsequent research. Second, in terms of empirical research, this paper constructs an evaluation system that includes new indicators such as public information, cultural development, and environmental governance, which more comprehensively reflects the actual level of equalization of marine public services. Third, by introducing the Dagum Gini coefficient, kernel density estimation, and convergence model, this paper makes an in-depth analysis of the regional differences, distribution dynamics, and convergence characteristics of the equalization of marine public services in China, reveals the differences and changing trends of equalization levels of marine public services in different regions, and provides a scientific basis for policy formulation. Through these studies, this paper not only enriches the theoretical and practical research on the equalization of marine public services, but also provides a decision-making reference for relevant government departments, which is conducive to the sustainable development of the marine economy.

2. Operation Mechanism, Index System, and Research Method

2.1. Operation Mechanism of Equalization of Marine Public Services

Through reviewing the existing literature, this paper holds that the equalization level of marine public services is realized by the joint action of both sides of supply and demand of marine public services. Due to the increasing industrial demand for the balanced development of the marine economy and the social demand for fairness of marine public services of residents in coastal areas, the equal supply level of marine public services is required to match it, and the equal supply level of marine public services is constructed by four subsystems: marine production services, marine social services, marine cultural services, and marine ecological services. The improvement in the equalization level of each subsystem stimulates the increase in the demand for equalization of marine public services. Under the joint action of both the supply and demand sides of marine public services, the equalization level of marine public services will be continuously improved, so as to achieve harmonious coexistence of people (see Figure 1).

2.2. Marine Public Services Equalization Level Evaluation Index System

Based on the theory of the marine economic system [20] and combined with the connotation of equalization of public services [21], this paper defines the connotation of equalization of marine public services. This paper holds that the equalization of marine public services means that the government takes the lead and the market and society participate together to ensure that all coastal areas enjoy roughly equal opportunities for marine development, and coastal residents enjoy roughly equal fruits of marine development. Based on the connotation of equalization of marine public services, and referring to relevant research results on equalization level measurement of public services, an evaluation index system of equalization level of marine public services is constructed from a total of 30 indexes in four dimensions of marine production services, marine social services, marine cultural services, and marine ecological services, and a comprehensive measurement is carried out (

Table 1. Indicator system for the equalization level of marine public services.

Target Layer	System Layer	Dimension Layer	Indicator Layer	Weight
Equalization of marine public services	Marine production service	Basic infrastructure	Port infrastructure density C1 (+)	0.086
			Cargo traffic by sea C2 (+)	0.030
			marine infrastructure investment per kilometer of coastline C3 (+)	0.062
		Safety guarantee	marine use fee amount C4 (+)	0.029
			Number of marine laws and regulations issued C5 (+)	0.063
		Public information	Distribution of coastal observation stations per kilometer of coastline C6 (+)	0.056
			Mobile phone exchange capacityper 10,000 people C7 (+)	0.010
			Number of Internet broadband ports per 10,000 people C8 (+)	0.025
	marine social service	Employment status	Sea-related employment ratio C9 (+)	0.021
			Per capita expenditure on sea-related unemployment insurance C10 (+)	0.068
		Medical and health	Per capita marine medical and health expenditure C11 (+)	0.034
			Number of healthy beds per 10,000 people C12 (+)	0.012
			Number of health workers per 10,000 people C13 (+)	0.008
		Social security	Per capita marine social security expenditure C14 (+)	0.039
			Number of community service agencies per 10,000 people C15 (+)	0.025
	marine cultural service	Educational level	Number of full-time marine teachers per 10,000 people C16 (+)	0.016
			Per capita expenditure on marine education C17 (+)	0.031
		Science and technology innovation	Per capita expenditure on marine science and technology C18 (+)	0.058
			Number of marine science and technology projects per 10,000 p C19 (+)	0.034
			Number of marine patents per 10,000 people C20 (+)	0.077
		Cultural development	Per capita expenditure on marine culture C21 (+)	0.04
			Library collection per 10,000 people C22 (+)	0.037
			Number of museums and cultural centers per 10,000 people C23 (+)	0.017
	marine ecological service	Environmental status	Per capita sea-related wetland area C24 (+)	0.018
			Per capita industrial wastewater discharge C25 (−)	0.006
			Per capita production of industrial solid waste C26 (−)	0.005
			Number of marine nature reserves C27 (+)	0.052
		Environmental governance	Per capita investment in marine environmental pollution C28 (+)	0.027
			Utilization rate of general Industrial Solid waste C29 (+)	0.008
			Harmless disposal rate of domestic waste C30 (+)	0.006

). Among them, the construction of marine infrastructure, the protection of marine laws and regulations, and the equalization of marine public information services are the basic services needed to satisfy the development of marine economy. The equalization of employment, medical and health care, and social security is an important reflection to measure the basic living standard of residents in coastal areas. The equalization of marine education, marine science, and technology and marine culture is the basic content of the marine economic development level. The equalization of marine ecological environment and environmental governance is the main factor to measure the quality of life of residents in coastal areas under the guidance of the concept of “green development”.

2.3. Research Method

2.3.1. Variable Fuzzy Recognition Model

The variable fuzzy recognition model is based on the relative membership function and builds a new model by changing the model and parameters to increase the credibility and reliability of evaluation, recognition, and decision making [22,23]. Therefore, the variable fuzzy recognition model is adopted in this paper to measure the equalization level of marine public services. The calculation formula is as follows:

$$V_A\left(u\right)=1/\left[{1+(d_g/d_b)}^a\right]$$

(1)

where $V_A\left(u\right)$ is the relative membership degree of equalization of marine public services. a is the optimization criterion parameter, a = 1 is the least one power criterion, and a = 2 is the least square criterion. $d_g$ is the optimal distance. $d_b$ is the aggregation distance. The calculation method is:

$$d_g={\left\{{\sum }_{i=1}^m\left[1-u_A{\left(u\right)}_i\right]\right\}}^{{\displaystyle \frac{1}{P}}}$$

(2)

$$d_b={\left\{{\sum }_{i=1}^m\left[w_i(u_A{\left(u\right)}_i\right]\right\}}^{{\displaystyle \frac{1}{P}}}$$

(3)

where $w_i$ is the weight of each index i in the equalization of marine public services. B is the relative membership vector corresponding to index i; p is the distance parameter, p = 1 is the Hamming distance, p = 2 is the Euclidean distance. There are four kinds of collocation between a and p: when a = 1 and p = 1, it is a fuzzy comprehensive evaluation model; when a = 1 and p = 2, it is the ideal point model; when a = 2 and p = 1, is the sigmoid function; and when a = 2 and p = 2, it is a fuzzy optimization model.

Based on the criteria of variable fuzzy recognition model level characteristic value judgment in the marine economy in coastal areas of China and related studies [24], this paper divides the equalization level of marine public services in coastal areas into five levels, and the evaluation criteria are shown in

Table 2. Marine public services equalization level: judgment criteria for each evaluation level.

Level	Evaluation Level	Value Range
Level 1	Low level	[0, 2)
Level 2	Lower level	[2, 2.5)
Level 3	Medium level	[2.5, 3)
Level 4	Higher level	[3, 4)
Level 5	High level	[4, 5)

.

2.3.2. Dagum Gini Coefficient

The Dagum Gini coefficient refers to the calculation method of the Gini coefficient based on subgroup decomposition proposed by Dagum. The Dagum Gini coefficient can solve the cross-overlap problem among samples when the level of all provinces in a region is not higher than that of all provinces in other regions. Therefore, the Dagum Gini coefficient is adopted in this paper to study and analyze the regional differences in the equalization level of marine public services in China’s coastal areas. For the specific calculation formula, see reference [25,26].

2.3.3. Kernel Density Estimation

Kernel density estimation is a density function often used to estimate the unknown in probability theory. In this paper, kernel density estimation is used to study the distribution dynamics of the absolute difference in the equalization level of marine public services in China’s coastal areas [27]. The calculation formula is as follows:

$$f_h\left(x\right)={\displaystyle \frac{1}{nh}}{\sum }_{i=1}^{n}K\left({\displaystyle \frac{x-x_i}{h}}\right)$$

(4)

where $f_h\left(x\right)$ is the estimated nuclear density; n is the number of samples; h is the bandwidth. $K\left({\displaystyle \frac{x-x_i}{h}}\right)$ is the kernel function; $x-x_i$ is the distance from the estimate point to the measurement point $x_i$.

2.3.4. Convergence Model

Alpha converges. α convergence reflects the convergence of differences in the equalization level of marine public services over time [28,29]. In this paper, the coefficient of variation is used to calculate α convergence of marine public services equalization, and the calculation formula is as follows:

$$\sigma ={\displaystyle \frac{1}{\overline{E}}}\sqrt{{\displaystyle \frac{1}{{\mathrm{n}}_{\mathrm{j}}}}{\displaystyle \sum _{i=1}^{n_{\mathrm{j}}}{(E_{\mathrm{ji}}-\overline{E})}^2}}$$

(5)

where $\overline{X}$ is the mean value of equalization of marine public services, $E_{ji}$ is the equalization value of marine public services of cities i in region j, and ${ n}_j$ is the number of cities in region j.

Beta converges. β convergence means that as time goes by, regions with a low equalization level of marine public services have a faster growth rate to catch up with regions with a high equalization level of marine public services, and finally reach a convergence state with the same growth rate, which is specifically divided into absolute beta convergence and conditional beta convergence [28,29].

By measuring the negative correlation between the growth rate of marine public services equalization and its initial level, absolute β convergence reflects the temporal change trend of marine public services equalization. The calculation formula is as follows:

$$\ln \left(E_{i,t+T}/E_{i,t}\right)/T=\mathrm{c}+\beta \ln \left(E_{i,t}\right)+{\epsilon }_{i,t}$$

(6)

where $E_{i,t+Th}$ and $e_{i,t}$ are the equalization values of marine public services in the i region at the end of the observation period and the beginning of the observation period, n is the number of samples, t is the year, T is the research period, c is the constant term, β is the regression coefficient, and is the error term. If β < 0, it indicates that there is a convergence trend in the equalization of marine public services; otherwise, it is a divergence trend. The convergence rate λ is obtained from the formula λ = −ln(1 − β)/T.

Condition β convergence means that the equalization level of marine public services in each region converges to its own steady state level over time under the consideration of other regional differences. The calculation formula is as follows:

$$\ln (E_{i,t+1}/E_{i,t})=\alpha +\beta \ln \left(E_{i,t}\right)+\gamma \ln X_{i,t}+{\epsilon }_{i,t}$$

(7)

where $X_{i,t}$ represents the conditional variables marine economic development level, government financial capacity, marine resource endowment, population density, and urbanization level; γ is its coefficient; other variables are the same as for the β convergence model. If β < 0, it indicates that the condition β converges for the equalization of marine public services, and otherwise it diverges.

2.4. Data Source

Due to the change in the statistical caliber of the marine Statistical Yearbook in 2006, the research time range of this paper is 2006–2019, and the research area covers 11 provinces and cities in China’s coastal areas (excluding Hong Kong, Macao, and Taiwan). According to the Outline of the National Plan for Marine Economic Development, China has divided its coastal areas into three major marine economic circles, namely, the Northern Marine Economic Circle (including the coasts and waters of Tianjin, Hebei, Liaoning, and Shandong), the Eastern Marine Economic circle (including the coasts and waters of Jiangsu, Shanghai, and Zhejiang), and the Southern Marine Economic Circle (including the coasts and waters of Fujian, Guangdong, Guangxi, and Hainan). The research data came from the China Statistical Yearbook (2007–2020), China Marine Statistical Yearbook (2007–2017), and China Marine Economic Statistical Yearbook (2018–2019).

3. Measurement of Equalization Level of Marine Public Services in China’s Coastal Areas and Analysis of Regional Differences

3.1. Measurement of Equalization Level of Marine Public Services in China’s Coastal Areas

Table 3. Measurement results of marine public services equalization in China’s coastal areas.

Year	Tianjin	Hebei	Liaoning	Shanghai	Jiangsu	Zhejiang	Fujian	Shandong	Guangdong	Guangxi	Hainan	Mean
2006	2.373	1.409	1.783	2.766	1.644	1.844	1.822	1.681	2.139	1.334	1.958	1.887
2007	2.421	1.441	1.828	2.954	1.718	1.923	1.933	1.748	2.183	1.369	2.014	1.957
2008	2.451	1.465	1.87	3.337	1.774	2.022	2.028	2.025	2.261	1.386	2.056	2.061
2009	2.632	1.503	2.075	3.373	1.844	2.05	2.151	1.945	2.31	1.49	2.142	2.138
2010	2.742	1.566	2.117	3.385	1.935	2.102	2.206	2.007	2.285	1.525	2.144	2.183
2011	2.778	1.645	2.197	3.398	2.037	2.177	2.264	2.05	2.274	1.567	2.212	2.236
2012	2.878	1.694	2.229	3.495	2.102	2.276	2.357	2.114	2.388	1.609	2.281	2.311
2013	2.977	1.724	2.288	3.603	2.174	2.404	2.461	2.184	2.375	1.679	2.352	2.384
2014	3.132	1.718	2.341	3.689	2.221	2.381	2.525	2.286	2.417	1.696	2.34	2.431
2015	3.138	1.879	2.487	3.824	2.282	2.461	2.757	2.33	2.541	1.798	2.448	2.54
2016	2.949	1.905	2.313	3.66	2.319	2.52	2.822	2.523	2.598	1.85	2.509	2.543
2017	3.073	1.983	2.275	3.824	2.367	2.577	2.864	2.563	2.713	1.912	2.552	2.609
2018	3.046	2.05	2.275	3.901	2.412	2.669	2.796	2.39	2.79	1.949	2.672	2.632
2019	3.332	2.061	2.425	4.014	2.458	2.725	2.854	2.487	2.836	1.996	2.718	2.719

provides detailed data on the equalization level of marine public services in 11 provinces and cities in China’s coastal areas from 2006 to 2019. Through in-depth analysis of these data, we can clearly observe that in the past 14 years, the level of marine public services equalization in China’s coastal areas has shown a steady upward trend. Specifically, the value of the equalization level of marine public services has increased year by year from 1.887 in 2006 to 2.719 in 2019. This growth trend shows that marine public services in China’s coastal areas are constantly improving and upgrading, and gradually achieving a more equitable and balanced allocation of resources. However, although the level of equalization of marine public services has improved, according to the results of data analysis, the current level is still in the medium range. This means that although some progress has been made, there is still much room for improvement. In order to further optimize marine public services, relevant departments need to continue their efforts and take effective measures to ensure that the equalization level of marine public services can reach a higher standard, so as to better meet the needs of residents in coastal areas and promote the sustainable development of the marine economy.

3.2. Regional Differences in Equalization of Marine Public Services in China’s Coastal Areas

3.2.1. Overall Difference and Intra-Regional Difference

According to Figure 2, the overall level of marine public services equalization in China’s coastal areas and the Gini coefficient within the three major marine economic circles show a slight downward trend in the fluctuation. Specifically, the change trend of the Gini coefficient in the Eastern Marine Economic Circle and the coastal areas is generally the same, showing a trend of “three rising and two falling”. The highest value of the Gini coefficient appeared in 2008, and the lowest value appeared in 2016. The Gini coefficient of the Northern Marine Economic Circle fluctuates greatly, reaching the peak value in 2014 and the lowest value in 2018. After that, the Gini coefficient shows a divergence trend, and the difference in the equalization level of marine public services in the northern marine economic circle may have an expanding trend. During the observation period, the Gini coefficient of the Southern Marine Economic Circle showed a downward trend, except from 2013 to 2016. At the end of the observation period, compared with the beginning, the Gini coefficient of the Southern Marine Economic Circle showed the largest decline, decreasing by 0.02332 (26.4%). The non-equalization degree of marine public services equalization in the Southern Marine Economic Circle has been significantly improved. To sum up, the equalization level of marine public services in China’s coastal areas as a whole and the three major marine economic circles all have disequilibrium characteristics, but the degree of disequilibrium has been improved. Although the regional differences within the Northern and Eastern Marine Economic Circles have been reduced, the degree of disequilibrium within the regions is still obvious. The key to improving the equalization level of marine public services in coastal areas is to pay attention to coordinating the differences in the equalization level of marine public services in the Eastern Marine Economic Circle.

3.2.2. Regional Differences Among the Three Major Marine Economic Circles

According to Figure 3, in general, the equalization level of marine public services in China’s coastal areas is different among different regions, and the regional differences between the North–South and East–South Marine Economic Circles show a slight downward trend in fluctuations, while the Gini coefficient of the regional differences between the North–East Marine Economic Circle remains basically unchanged at the end and beginning of the observation period. Specifically, in terms of the numerical value of the Gini coefficient, from 2006 to 2019, the numerical order of the Gini coefficient between the three major marine economic circles has always been North–East Marine Economic Circle > East–South China Sea Marine Economic Circle > North–South Marine Economic Circle. In terms of the variation trend of the Gini coefficient, the variation trend of the difference curves between the North and South and the East and South Marine Economic Circles was the same and showed a slight downward trend. The Gini coefficient between the North and South Marine Economic Circles decreased by 8% during the observation period, and the Gini coefficient between the East and South Marine Economic Circles decreased by 7.6% during the observation period, showing a changing trend of “three rises and two declines”. The turning point of change is the same. The inter-regional Gini coefficient of the North–East Marine Economic Circle remained basically unchanged at the end and beginning of the observation period. In summary, although the regional differences between the East–South Marine Economic Circle have been reduced, the regional differences still exist in the long run, and the regional differences between the North–East Marine Economic Circle remain basically unchanged and still rank the highest among the three marine economic circles. The reason for this may be that the Northern Marine Economic Circle has a higher level of marine economic development, but the implementation of marine ecological protection is insufficient. As a result, the ecological environment of residents in coastal areas has deteriorated, resulting in a low level of equalization of marine public services, while the Eastern Marine Economic Circle attaches importance to the development of marine science and technology and marine education, and focuses on sharing marine science and technology achievements with residents in coastal areas, resulting in a high level of equalization of marine public services, and thus in a large regional gap between the Northern and Southern Marine Economic Circles.

3.2.3. Sources of Regional Differences and Their Contribution Rates

According to Figure 4, inter-regional differences are the main source of the disparity in the equalization level of marine public services in China’s coastal areas. On the whole, the inter-regional difference contribution rate curve and the contribution rate curve of supervariable density presented a symmetrical distribution. During the observation period, the inter-regional difference contribution rate curve and the contribution rate curve of supervariable density presented a fluctuating upward trend and a fluctuating downward trend respectively, while the intra-regional difference contribution rate curve changed gently and presented a slight downward trend. Specifically, the contribution rate of inter-regional differences reached a minimum value of 25% in 2006, then reached 39% in 2013 through “N-type” fluctuations, then reached a maximum value of 42% in 2018 through “N-type” fluctuations, and then showed a downward trend. The change trend of the contribution rate of supervariable density is opposite to that of the contribution rate of the inter-regional difference. The contribution rate of supervariable density reached a maximum value of 45% in 2006, reached 32% in 2013 after an inverted “N” type change, then reached a minimum value of 31% in 2018 after an “N” type change, and then showed an upward trend. The contribution rate of intra-regional differences changed steadily and showed a slight downward trend during the observation period. Taking 2006 as the base period, the contribution rate of intra-regional differences and supervariable density decreased by 1.97% and 6.94%, respectively, in 2019, while the contribution rate of inter-regional differences increased by 8.91%. The source of contribution rate changes from supervariable density to inter-regional differences. Due to the characteristics of openness and the complexity of the marine economy, the equalization level of marine public services exhibits a cross-over phenomenon among coastal areas. With the standardization of marine management and systematic management of the marine economy, the source of the overall difference of equalization of marine public services further changes to inter-regional differences. Therefore, the main reason for the difference in the equalization of marine public services is the difference between regions. Paying attention to the coordinated development of the three marine economic circles will help improve the equalization level of marine public services in coastal areas.

4. Dynamic Evolution of Marine Public Services Equalization in China’s Coastal Areas

In this paper, the kernel density estimation method is used to analyze the dynamic evolution and evolution law of the equalization level of marine public services in China based on an absolute difference perspective. Figure 5 shows the results of kernel density estimation and overall evolution characteristics.

5. Convergence Analysis of Equalization of Marine Public Services in China’s Coastal Areas

5.1. Convergence Analysis of α

It can be seen from Figure 6 that the α convergence values of China’s coastal areas as a whole and the three major marine economic circles all show a slight downward trend in the fluctuation, and the ending values are all lower than the initial values of the period, that is, there is an α convergence feature, indicating that the differences in the equalization level of marine public services in China’s coastal areas will eventually converge to the same steady state level. Specifically, comparing the average value of α convergence of the three major marine economic circles, it is found that the average value of α convergence of the Eastern Marine Economic Circle is the largest (0.240), the average value of α convergence of the Northern Marine Economic Circle is second (0.184), and the average value of α convergence of the Southern Marine Economic Circle is the smallest (0.149). This shows that the difference in the equalization of marine public services in the Eastern Marine Economic Circle is larger than that in other regions, which is caused by the large differences in government financial capacity and population density among provinces and cities in the Eastern Marine Economic Circle, while the distribution of marine resource endowment and population density among provinces and cities in the Southern Marine Economic Circle is closer to the average, so the α convergence value is the smallest. The results are basically consistent with the previous Dagum Gini coefficient calculation results.

5.2. Absolute β Convergence Analysis

According to

Table 4. Evolution trend of β convergence of marine public services equalization in China’s coastal areas.

V	China’s Coastal Areas		Northern Marine Economic Circle		Eastern Marine Economic Circle		Southern Marine Economic Circle
	Absolute Convergence	Conditional Convergence	Absolute Convergence	Conditional Convergence	Absolute Convergence	Conditional Convergence	Absolute Convergence	Conditional Convergence
β	−0.024 **	−0.546 *** (−8.40)	−0.120 ** (−2.53)	−0.754 *** (−5.83)	−0.106 *** (−3.35)	−0.415 *** (−5.21)	−0.046 * (−1.86)	−0.290 *** (−3.59)
c	0.047 *** (−5.43)	−0.783 ** (−2.06)	0.120 *** (−3.24)	−1.303 *** (−4.86)	0.127 *** (−4.34)	−0.715 *** (−3.44)	0.063 *** (−3.33)	−0.391 ** (−2.38)
X1		0.032 (−1.56)		0.094 *** (−3.32)		0.089 *** (−3.24)		0.048 *** (−3.53)
X2		0.054 *** (−2.84)		0.086 *** (−3.88)		0.013 (−0.79)		0.014 (−1.65)
X3		0.003 (−0.96)		0.009 (−1.27)		−0.006 * (−1.79)		0.004 (−0.7)
X4		0.04 (−0.62)		0.032 (−1.04)		0.024 * (−1.98)		0.016 (−0.7)
X5		0.356 ** (−2.46)		0.131 (−1.46)		0.017 (−0.11)		−0.012 (−0.08)
R2	0.0357	0.3859	0.1197	0.4559	0.2423	0.5481	0.0686	0.2793
F	5.21	13.2	6.39	6.28	11.19	6.47	3.46	2.91

Note: *, ** and *** are significant at the level of 10%, 5% and 1% respectively, and the values in brackets are standard deviation.

, the β coefficients of the coastal area as a whole and the three major marine economic circles are significantly negative, that is, they all have the absolute β convergence feature, indicating that under the same conditions, the differences in the equalization level of marine public services among provinces and cities in each region will eventually converge to the same steady level over time. Provinces with a low equalization level of marine public services have a faster growth rate than provinces with a high equalization level of marine public services, that is, there is a “catch-up effect”. Specifically, the convergence rate of the Northern, Eastern, and Southern Marine Economic Circles is 0.91%, 0.8%, and 0.34% respectively, and the convergence rate is the fastest in the Northern Marine Economic Circle, mainly because Hebei and Liaoning have put forward measures to strengthen marine infrastructure service capabilities and build public service platforms for marine science and technology research and development in their marine economic development plans in recent years. In order to catch up with the provinces and cities with a high level of equalization of marine public services, the Northern Marine Economic Circle converges the fastest.

5.3. Conditional β Convergence Analysis

According to Table 4, the β coefficients of the coastal areas as a whole and the three major marine economic circles are significantly negative, that is, conditional β convergence characteristics exist in all of them. This indicates that, when considering the development level of the marine economy, financial expenditure capacity, marine resource endowment, population density, urbanization level, and other factors, with the passage of time, the difference in the equalization level of marine public services among provinces and cities in the region will eventually converge to the same steady state level. Specifically, the coefficient of marine economic development level is significantly positive in the three major marine economic circles, indicating that the development of the marine economy will improve the equalization level of marine public services, but has a restraining effect on reducing the differences in the equalization level of marine public services between regions. The unbalanced development of the marine economy is the leading factor causing the differences in the equalization level of marine public services. The coefficient of fiscal expenditure capacity is significantly positive in the coastal areas as a whole and in the Northern Marine Economic Circle, but not in other regions, indicating that the increase in government fiscal expenditure will improve the equalization level of marine public services, but has a restraining effect on narrowing the differences in the equalization level of marine public services between regions. In coastal areas, the governments of different provinces and cities have different financial expenditures on marine public services, which leads to regional differences in the equalization of marine public services. Marine resource endowment and population density coefficients are significantly positive and negative, respectively, in the Eastern Marine Economic Circle, but are not significant in other regions, indicating that the development and utilization of marine resource endowment will improve the equalization level of marine public services in the Eastern Marine Economic Circle. However, due to the large population density in the Eastern Marine Economic Circle, there is an uneven distribution of public resources, thus affecting the equalization level of marine public services. The urbanization level coefficient is significantly positive in the coastal areas as a whole, indicating that the scale effect caused by the increase in the urbanization rate will improve the equalization level of marine public services. However, due to the different urbanization processes of various provinces and cities in the coastal areas, there is a certain inhibitory effect on reducing the regional differences in the equalization level of marine public services.

6. Conclusions and Suggestion

6.1. Conclusions

Based on the connotation of equalization of marine public services, this paper constructs a comprehensive evaluation index system for equalization of marine public services from four dimensions: marine production services, marine social services, marine cultural services, and marine ecological services, and adopts a variable fuzzy identification model to measure the equalization level of marine public services in 11 provinces and cities in China’s coastal areas from 2006 to 2019. Using the Dagum Gini coefficient, kernel density estimation model, and convergence model, regional differences, distribution dynamics, and convergence characteristics are studied, and conclusions are drawn as follows:

(1) Overall, the equalization level of marine public services in China’s coastal areas showed an increasing trend year by year from 2006 to 2019. In terms of spatial distribution, the equalization level of marine public services in coastal areas presents a non-equilibrium distribution pattern, which is low in the northeast coastal area and high in the southeast coastal area.

(2) According to the Dagum Gini coefficient and its decomposition results, the overall regional differences in the equalization level of marine public services in China’s coastal areas showed a slight downward trend during 2006–2019, and the regional differences narrowed somewhat. The equalization level of marine public services in the Eastern Marine Economic Circle region is the most different. The difference in marine public services between the Northern and Eastern Marine Economic Regions is the largest. The difference between regions is the main reason for the difference in the equalization level of marine public services in China’s coastal areas.

(3) According to the estimated distribution curve of nuclear density, the equalization level of marine public services in China’s coastal areas as a whole and the three major marine economic circles showed an overall upward trend during 2006–2019, and the absolute differences showed an expanding trend. China’s coastal areas as a whole and the three major marine economic circles show a “Matthew effect”, and the overall distribution of China’s coastal areas is bimodal to multi-modal. The Northern Marine Economic Circle showed a bimodal distribution in 2006–2008 and 2016–2019, and a multi-modal distribution in 2008–2016, while the Eastern and Southern Marine Economic Circles always showed a bimodal distribution.

(4) According to the convergence characteristics, α convergence and β convergence exist in the equalization of marine public services in China’s coastal areas, of which the α convergence value of the Eastern Marine Economic Circle is the greatest, and the absolute β convergence value of the Northern Marine Economic Circle is the greatest. The levels of marine economic development, fiscal expenditure capacity, and urbanization have a strong influence on the convergence characteristics of marine public services equalization in China’s coastal areas.

6.2. Suggestion

The improvement in the equalization level of marine public services is a direct path to improve the happiness of residents in coastal areas, and an important factor to achieve stable and sustainable development of the marine economy. According to the above research, the insights into the equalization development of the marine public service level are as follows:

(1) Pay attention to the coordinated development of coastal areas between regions. Strengthen the linkage mechanism of marine infrastructure and marine resources, take full advantage of the marine resources of the three ocean circles, and strengthen the division of labor and cooperation among regions. This will improve the inter-regional marine coordinated management mechanism, and strengthen the management of inter-regional marine coordinated development through administrative means by formulating joint maritime law enforcement actions and maritime emergency law enforcement plans.

(2) Increase the financial expenditure of provinces and cities with a low equalization level of marine public services. Increase the intensity of transfer payments, increase the scale of transfer payments, focus on helping provinces and cities with a low equalization level of marine public services in the three marine economic circles to solve their financial problems, and promote coordinated development among regions. This will adjust the structure of fiscal expenditure, and increase expenditure on marine education, marine science and technology, and marine social security in Liaoning, Hebei, Guangxi, and other places, and improve the overall level of equality in marine public services.

(3) Pay attention to the convergence characteristics of the equalization level of marine public services. While narrowing the differences in the equalization of marine public services between regions, attention should be paid to the coordination of the development speed of equalization of marine public services among provinces and cities in coastal areas, that is, while increasing the government financial expenditure in Liaoning, Hebei, Guangxi, and other places, the expanding effect of equalization of marine public services in Tianjin, Shanghai, Guangdong, and other places should also be taken into account.

6.3. Discussion

Previous studies mostly focused on a single dimension of equalization of public services, such as education, medical care, or infrastructure [30,31], whereas this study builds a more comprehensive evaluation index system from the multi-dimensional perspective of marine public services. Most studies have found that the level of equalization of public services is different in different regions, and, with the passage of time, this difference has a trend of decreasing. However, this study pays special attention to regional differences in marine public services, revealing differences within and between marine economic circles, which have been less closely examined in previous studies.

In theory, this research will enrich the research field of equalization of public services, especially in the marine field. The results show that the equalization level of marine public services is not only related to the level of regional economic development, but also closely related to the policy orientation and resource allocation ability of local governments. In practice, this study provides a reference for policy makers on how to optimize the allocation of marine public services resources and reduce regional differences. In particular, for the differences within and between the marine economic circle, this study provides a targeted analysis, which can help in formulating a more accurate regional balanced development strategy.

Although this study has achieved certain results, there are still some limitations. First, due to data availability limitations, this study only covers the time span from 2006 to 2019, and future studies can expand the time range to obtain a longer-term equalization trend. Secondly, this study mainly focuses on the coastal areas of China, and future studies can expand the vision to the global scope and compare the equalization level of marine public services in different countries and regions, so as to provide references for international cooperation and exchanges. Finally, with the continuous development of the marine economy and the progress of marine science and technology, future research should focus on emerging marine public services, such as marine renewable energy services and deep-sea resources development services, in order to adapt to the new trend of marine economic development.