Port Service Coordination Sustainability in the Yangtze River Delta in China Based on Spatial Effects

Abstract

With the prevalence of international trade protectionism and transformation and the upgrading of the domestic market structure, the contradiction between the demand for and the competitive development of the port market in the Yangtze River Delta in China has become increasingly prominent. The 19 major ports of the Yangtze River Delta in China were selected for this study, and using the methods of index evaluation, gravitational model, and spatial interpolation, the spatial effects in the hinterland were calculated from three dimensions, central potential, spatial gravity and distribution convenience, and the regional coordination of port services. The results show that the potential of the Shanghai Port and Ningbo Zhoushan Port in China is stronger, and the difference in the distribution of the ports is quite clear. The spatial gravity of each port city can be superimposed over one another to form a clear dense semi-circular zone, and the ability of the marginal ports to participate in this zone is weak. The convenience of their distribution in the hinterland changes from being location-dependent to traffic-dependent. The service gap in the hinterland of the port system is more significant, but the expansion of spatial effects makes the sustainability of regional coordination gradually improve. Finally, several policy suggestions are proposed to ensure ecological responsibility among resource-oriented enterprises.

1. Introduction

With the advantages of an open location and hinterland resources, the Yangtze River Delta in China has formed a complete port system. The viewpoint represented by the theory of “port overcapacity” holds that port construction in the Yangtze River Delta region tends to be competitive and decentralized [1]. At the same time, due to the strong dependence of long-distance multimodal transport on shoreline endowment and transportation facilities, it has been difficult for this system to support the industrial development of the whole region, especially the marginal cities, and the integration of port resources [2]. Views changed from a centralized layout to decentralized distribution and then to diversified cooperation. Considering the regional development laws in the port hinterland, with the continuous improvement in the ability of ports to integrate their resources into the hinterland cities, the process of regional integration has also been accelerated in the processes of system division and transshipment cooperation. Port service coordination could be characterized as a balanced spatial service system formed by regional ports in competition and cooperation. For the Yangtze River Delta region, the spatial structure of the port system is more complex, and the service statuses of the ports vary greatly among regions due to large hub ports such as Shanghai Port, Ningbo Zhoushan Port, Suzhou Port, and so on. Therefore, only by clarifying the cooperation status and service ability of the central ports in the port system can we scientifically evaluate the status of the hinterland affected by the ports.

The spatial arrangement of port services has a relative regional pattern formed by the cooperation and competition between neighboring ports. Port center potential is not only the main basis for the strength of the port service hinterland but also the important premise for the scale structure and hinterland division of a port system. In a multiport area, the ports with a strong central potential can occupy more of the hinterland with the help of a centralized multimodal transport system. With the weakening of the limitation of physical space on port services, the scope of ports’ functions to radiate into the hinterland is also expanding. In this process, the functions of port services are differentiated. Large ports have changed from simple cargo ports to comprehensive hub ports that include financial and settlement services, while small and medium-sized ports have been transformed to take on subsidiary or professional functions. The differences in the spatial organization of the collection and distribution networks in regions are the basis for the integrated allocation of port system resources. Under the premise of homogenizing the distribution of port facilities at the management level, the collection and distribution network and the city in the integrated region will follow the principle of minimum cost when choosing port services and the gravity model based on the scale economy and distance attenuation rule can better reflect the choice of a port hinterland.

2. Literature Review

With the increasingly perfect service function of ports for regional economic development, many scholars have tried to analyze the spatial relationship between ports and their internal ports from the perspective of the mechanism of the formation and evolution of port systems since the end of the 20th century. Through the establishment of a port system development model, Notteboom et al. [3] found that, in the environment of economic globalization and market integration, the relationships between ports would eventually change to the regional mode. Lamb indirectly reflected on the degree of connectivity and coordination between the ports from the service modes of the ports in the shipping network based on the sea hinterland. Fan et al. [4] reflected on the coordinated state of global ports through the flow of container trade. At the same time, some scholars took typical ports as examples to analyze the influence of port spatial organization on the hinterland. Zhang et al. [5] thought that the evolution of regional port combination and transportation patterns could affect the regional industrial interaction pattern. Jiang thought that cities could directly improve their regional portal function through port services. The Yangtze River Delta is an important port space and gathering place in China. Many scholars pay attention to the level and characteristics of port shipping service. Jiang et al. [6] carried out a comprehensive evaluation of the coordination between ports through cluster analysis. Talley and Ng [7] proposed and studied a new performance evaluation method using port congestion probability as a proxy variable for port efficiency by introducing the equilibrium theory of cargo port selection. By introducing the new concept of composite connectivity and innovatively using two-stage data envelopment analysis (DEA) and complex network theory, Wang et al. [8] evaluated the efficiency of port “basic connectivity” and used it as an input variable to measure the strength of port centrality. Chen et al. [9] have obtained a lot of spatiotemporal data on port activities based on port monitoring videos, which can be used to improve port management efficiency.

The existing research focused on summarizing the competitive and cooperative relationships within the spatial evolution of a regional port system from a theoretical perspective, or evaluating the hinterland service structure of the port system, but seldom considered the effect of coordination from the perspective of a spatial comparison of port service. In particular, due to the lack of port connectivity data, it is rare for quantitative evaluations of the port service cooperation pattern to be conducted [10,11,12,13,14]. Therefore, this study adopts the spatial perspective to analyze the regional coordination of port services from multiple perspectives.

3. Methodology

3.1. Calculation of Port Space Effect

The study reflects on the coordination level of port services by comparing the service differences between the port systems of different regions [15,16,17]. Therefore, the service capacity of the different ports should be defined, and then the service capacity of different hinterlands can be calculated. According to analysis on the development rules and driving characteristics of the port hinterlands system [18,19], spatial effects of the port service are calculated as follows:

$${{\displaystyle E}}_i={\displaystyle \sum _{j=1}^n{{\displaystyle L}}_i{{\displaystyle G}}_{ij}{{\displaystyle R}}_{ij}}\hspace{1em} {{\displaystyle E}}_j=\max \left\{{\displaystyle \frac{{{\displaystyle E}}_i}{{{\displaystyle d}}_{ij}}}\left|j\in \left(1,2\cdots ,N\right)\right.\right\}$$

(1)

E_i is the total spatial effect of port i on all regions, and L_i is the central potential of port i. G_ij is the gravity value of port i and city j, and R_ij is the convenience level of port i to the inland freight service. E_j refers to the port space effect of hinterland j. Considering the competition of port systems, the maximum value of many port space effects is taken.

(1)

Port center potential

Port central potential refers to the concept of physics reflecting the possibility of interaction among all units in the system. The study is used to measure the total capacity of the port to influence the region based on its own development scale, location conditions, and service functions [20]. The central potential represents the service potential of a port to all cities in the study, usually represented by the direct scale indicators such as cargo throughput and container throughput of this port or by alternative indicators that reflect the unique functions of the port. The study considers that the central potential of a port is not only reflected in its cargo transfer function but also in its comprehensive service capabilities of trade, finance, logistics, and other aspects. Therefore, indicators are selected from the scale of port development and the level of urban functional support to construct an evaluation system for the port central potential indicators (as shown in

Table 1. Evaluation result value of initial evaluation indices of ecological responsibility of resource-oriented enterprises.

Primary Indicators	Secondary Indicators	Unit
Port development scale	Port cargo throughput	10 thousand tons
	Container throughput	10 thousand TEUs
	Proportion of foreign trade goods	Percentage point
	Proportion of container cargo	Percentage point
City function level	GDP of port cities	RMB 100 million
	Industrial added value of port cities	RMB 100 million
	Total deposits of financial institutions in port cities at the end of the year	RMB 100 million
	Total import and export trade of port cities	RMB 100 million
	Total amount of post and telecommunication services in port cities	RMB 100 million
	Total retail sales of consumer goods in port cities	RMB 100 million

).

In terms of calculating the central potential, considering the possible correlation of relevant indicators, the factor analysis method is selected to reduce the original data into a few common factors [21] and then calculate the comprehensive score of the central potential based on the above analysis. The calculation formula is as follows:

$$\left\{\begin{array}{c}{{\displaystyle x}}_1={{\displaystyle a}}_{11}{{\displaystyle f}}_1+{{\displaystyle a}}_{12}{{\displaystyle f}}_2+\dots +{{\displaystyle a}}_{1n}{{\displaystyle f}}_n+{{\displaystyle \xi }}_1\\ {{\displaystyle x}}_2={{\displaystyle a}}_{21}{{\displaystyle f}}_1+{{\displaystyle a}}_{22}{{\displaystyle f}}_2+\dots +{{\displaystyle a}}_{2n}{{\displaystyle f}}_n+{{\displaystyle \xi }}_2\\ ⋮\\ {{\displaystyle x}}_{10}={{\displaystyle a}}_{101}{{\displaystyle f}}_1+{{\displaystyle a}}_{102}{{\displaystyle f}}_2+\dots +{{\displaystyle a}}_{10n}{{\displaystyle f}}_n+{{\displaystyle \xi }}_{10}\end{array}\right.$$

(2)

$${{\displaystyle X}}_i={{\displaystyle \beta }}_1{{\displaystyle f}}_1+{{\displaystyle \beta }}_2{{\displaystyle f}}_2+\cdots +{{\displaystyle \beta }}_n{{\displaystyle f}}_n$$

(3)

x_i is the original variable after standardization, which can be summed up as a linear combination of n vectors f_i. ${\xi }_i$ is the error term. x_i is the final score of city i central potential obtained from each factor. The weight coefficient of each factor ${\beta }_i$ is expressed by variance contribution rate.

(2)

Gravity value of port city

The urban agglomeration led by channel construction has made the flow of people and logistics between cities more closely connected, and the spatial attraction between cities has also been enhanced. Similarly, in order to enhance their export-oriented economic functions, port cities actively seek economic cooperation with neighboring ports by taking the advantages of ports, thereby generating the spatial gravity between port cities. When a port is faced with multiple market cooperation options, the marginal cooperation cost and transportation turnover cost of the port will be comprehensively considered [22]. Port cities with higher service levels and closer distances often have stronger appeal. The calculation formula is as follows:

$${{\displaystyle G}}_i={\displaystyle \sum _{j=1}^n\sqrt{\frac{{{\displaystyle m}}_i{{\displaystyle m}}_j}{{{\displaystyle D}}_{ij}^2}}}$$

(4)

G_i is the comprehensive gravity value of the city where port i is located. m_i and m_j are corresponding indicators of port city size. The study selects the comprehensive value of GDP, port number, and cargo throughput to replace the distance index and selects the shortest road distance.

(3)

Convenient level of collection, distribution, and transportation

Port collection and distribution refer to the use of the basic transportation network serving cities by the ports to transport, concentrate, and allocate goods through waterway and land transfers [23]. The convenient collection and distribution system can directly reduce the cost of goods circulation between ports and hinterlands, as well as within the hinterlands. The factors affecting convenience of cargo collection and distribution between ports and service cities mainly include urban traffic convenience, port city accessibility, and location conditions of collection and distribution. Therefore, the calculation formula for the convenience of collection and distribution is defined as:

$$R_{ij}={\displaystyle \frac{S_j\times K_j}{D_{ij}}}$$

(5)

$$R_i={\displaystyle \sum _{j=1}^n{R}_{ij}}$$

(6)

where S_j is the traffic convenience of city j, which is replaced by highway mileage per unit area, k_j is the location condition of city j, expressed by the number of directly adjacent cities, D_ij is the accessibility from port i to city j and expressed by the shortest road transportation time.

3.2. Data Processing and Sources

Research objects mainly involve cities and ports in the Yangtze River Delta of China. In terms of cities, considering that service intensity of ports in the Yangtze River Delta of China is concentrated in the coastal and Yangtze River estuary areas and remote areas have a strong dependence on other port clusters, according to the national definition of high-quality integration in the Yangtze River Delta, Shanghai, Zhejiang, Jiangsu, and Anhui provinces are selected as the hinterland research objects [24]. In terms of ports, based on the most recently released “China Port Statistical Yearbook”, Shanghai Port, Ningbo Zhoushan Port, Jiaxing Port, Taizhou Port, and Wenzhou Port are selected. Huzhou Port and Lianyungang Port, Nantong Port, Suzhou Port, Taizhou Port, Jiangyin Port, Changzhou Port, Zhenjiang Port, Yangzhou Port, Nanjing Port, Ma’anshan Port, Wuhu Port, Tongling Port, Hefei Port, and other major ports are included in the statistics for the study area. It should be pointed out that in 2006, Ningbo Port and Zhoushan Port were essentially merged and this article will analyze them as a unified entity. The administrative division of the research area was drawn based on the 1:1 million standard data in the National Basic Geographic Information Database [25,26], and the coordinates of each port were searched using Google Earth and uniformly entered into ArcGIS 10.2 software, as shown in Figure 1. The index data are mainly from China Port Yearbook in 2012 and 2018, China Urban Statistical Yearbook, and statistical websites of three provinces and cities. In terms of distance data, actual distance in 2011 is derived from the Atlas of Highway Operating Mileage in China (2011 Edition), while the mileage in 2017 was calculated based on the impedance coefficient set in the ArcGIS database.

4. Empirical Analysis

4.1. Analysis of Port Center Potential

Firstly, based on the constructed index system of the port center potential, the panel data of ports in the Yangtze River Delta region from 2011 to 2017 were standardized, and principal component analysis was performed by using SPSS19.0 software, so as to calculate the strength of port center potential (as shown in

Table 2. Score of port center potential in Yangtze River Delta from 2011 to 2017.

Ports	2011	2013	2015	2017	Ports	2011	2013	2015	2017
Shanghai Port	0.695	0.792	0.897	0.891	Jiangyin Port	0.116	0.128	0.132	0.156
Ningbo Zhoushan Port	0.387	0.498	0.553	0.594	Changzhou Port	0.046	0.055	0.065	0.079
Jiaxing Port	0.044	0.062	0.067	0.082	Zhenjiang Port	0.059	0.077	0.079	0.120
Taizhou Port	0.043	0.053	0.059	0.055	Yangzhou Port	0.051	0.055	0.067	0.075
Wenzhou Port	0.062	0.073	0.338	0.080	Nanjing Port	0.129	0.181	0.218	0.223
Huzhou Port	0.066	0.070	0.049	0.055	Ma’anshang Port	0.026	0.038	0.044	0.041
Lianyungang Port	0.089	0.124	0.127	0.123	Wuhu Port	0.040	0.052	0.067	0.063
Nantong Port	0.093	0.123	0.142	0.159	Tongling Port	0.017	0.026	0.035	0.035
Suzhou Port	0.242	0.315	0.371	0.348	Hefei Port	0.035	0.057	0.073	0.087
Taizhou Port	0.056	0.081	0.093	0.117

).

According to the calculation results in Table 2, it can be seen from the distribution trend of port central potential that there are significant changes in the center potential of each port, but the trend differences are significant. The service potential of ports in Yangtze River Delta to the hinterland still shows spatial differentiation. Shanghai Port, Ningbo Zhoushan Port, and Suzhou Port have always been in the top three positions, among which Shanghai Port has become the core port in the Yangtze River Delta region with its absolute advantages of cargo transshipment, especially container transshipment, and a comprehensive port and shipping trading service platform. The center potential of Ningbo Zhoushan Port has increased steadily from 0.387 to 0.594, indicating that it has developed from a subsidiary port to a hub port for sea to sea transit in the spatial game with Shanghai Port, relying on the characteristics of hinterland industry demand and service features. Suzhou Port, relying on its unique location at the mouth of the Yangtze River, has an advantage in the hinterland market during the process of river–sea intermodal transportation. However, with the promotion of port system reform based on the principle of “one port, one city”, the surrounding ports have gradually established a port system guided by the local market, which reduced the strength of Suzhou Port’s central potential to certain extent. In terms of other ports, there are obvious differences in the distribution of center potential strength among provinces. Jiangsu Province has established a more balanced port system with the advantages of the Yangtze River coastline and relying on the industrial scale of cities. For example, the center potentials of Nanjing Port, Lianyungang Port, Jiangyin Port, Taizhou Port, and Zhenjiang Port all exceed 0.1. The port system of Zhejiang Province in China is more in line with the “center periphery” structure, with the center potential of ports other than Ningbo Zhoushan Port not exceeding 0.1. Due to the weak port service capacity and unclear growth trend in Anhui Province, it indicated that the supporting role of hinterland economy in spatial cooperation is not strong.

4.2. Analysis of Gravitation Between Port Cities

Taking the spatial gravity model as a reference, the gravity values of various ports in the Yangtze River Delta in 2011 and 2017 were calculated, and the connection scale was classified by ArcGIS 10.2 software (as shown in Figure 2). It can be seen that the overall connection pattern of the port system has not undergone significant changes, and a semi-circular dense connection belt has always existed between the two shipping channels of the Yangtze River and the coast. Among them, Shanghai Port has always maintained the top two links with Suzhou Port and Ningbo Zhoushan Port, relying on its own perfect port and shipping service system and logistics capacity, and its connection level with other ports has also been improved, always occupying a dominant position in the port system. As an important medium connecting inland ports and coastal ports, Suzhou Port has a more balanced gravitation with surrounding ports, especially in the centrality of ports system, However, its connection with Zhejiang ports such as Huzhou Port has weakened. Although Ningbo Zhoushan Port in China has an advantage in cargo throughput capacity, it only forms a high-intensity connection with surrounding large ports such as Shanghai Port and Suzhou Port, indicating its service functions cannot meet the leading demand for regional ports. From the distribution of gravity levels among ports in various provinces, it can be seen that ports in Jiangsu Province have a more dense organizational system, which is attributed to the high-quality coastline in the lower reaches of the Yangtze River in China, which can support more regional port layouts. A complete port system is conducive to enhancing the market share of coastal goods. With the support of cooperation in the Yangtze River Economic Belt, various ports in Anhui Province have obvious port connections. The gravity level of ports in Zhejiang Province is generally low, mainly due to the scattered distribution of ports, but the growth rate is relatively obvious, indicating the feeding capacity of hinterlands to the core ports has been significantly improved.

4.3. Analysis on the Convenience of Collection and Distribution in Port Hinterland

Based on the analysis of the potential and gravity of port services, standardized port index and distance index are used to calculate the score of the hinterland collection and distribution convenience of each port (as shown in

Table 3. The 2011–2017 Yangtze River Delta port hinterland collection and distribution convenience score.

Ports	2011	2013	2015	2017	Ports	2011	2013	2015	2017
Shanghai Port	1.009	0.994	0.981	0.824	Jiangyin Port	1.017	1.838	1.323	1.412
Ningbo Zhoushan Port	0.722	0.688	0.873	0.964	Changzhou Port	1.875	1.220	1.629	1.882
Jiaxing Port	0.822	0.942	1.008	1.012	Zhenjiang Port	1.746	1.688	1.533	1.663
Taizhou Port	1.187	1.122	1.264	1.280	Yangzhou Port	1.072	1.322	1.227	1.149
Wenzhou Port	1.061	1.170	1.148	1.238	Nanjing Port	1.881	1.629	1.130	1.997
Huzhou Port	1.265	1.643	1.631	1.681	Ma’anshang Port	1.970	1.034	1.595	0.910
Lianyungang Port	1.047	1.026	1.088	1.112	Wuhu Port	0.960	1.110	1.257	1.233
Nantong Port	1.350	1.993	1.457	1.455	Tongling Port	1.271	0.945	0.931	1.002
Suzhou Port	1.989	1.920	2.164	1.948	Hefei Port	1.575	1.409	1.429	1.549
Taizhou Port	1.045	1.509	1.471	1.356

).

According to the calculation results, it can be seen that there is a significant difference in the convenience of collection and distribution of various ports compared to their central potential. In 2011, Suzhou Port, Ma’anshan Port, and Wuhu Port ranked in the top three, mainly due to the fact that the three ports go deep into the hinterland of the Yangtze River Delta, resulting in stronger spatial extension of cargo transportation and location advantages in situations where transportation infrastructure is insufficient to support resource allocation efficiency. However, with the increasing popularization of regional corridor construction supported by road networks, ports located in the core of urban agglomerations or metropolitan areas are more likely to diffuse goods in the surrounding markets, resulting in greater cooperation and transshipment pressure for ports on the geographical edge of the economic zone. By 2017, the top three ports had shifted to Nanjing Port, Suzhou Port, and Changzhou Port. As the hub ports of international and domestic freight transportation, Shanghai Port and Ningbo Zhoushan Port often have an advantage of sea to hinterland in the logistics system, but they need to rely on branch ports or land sea intermodal transportation to better extend the market from land to hinterland. From the comparison of different provinces, Jiangsu and Anhui provinces generally have higher convenience in collection and distribution, which is not only influenced by geographical conditions but also by the inherent advantages provided by the Yangtze River impact plain for the construction of transportation networks in the two provinces.

4.4. Analysis on the Overall Spatial Effect of Ports in the Yangtze River Delta

Based on the calculation of the central potential of each port, the city gravity value, and the convenience of collection and distribution, the comprehensive score of each port’s spatial effect is obtained by multiplying the scores (as shown in

Table 4. Score of port spatial effect in Yangtze River Delta from 2011 to 2017.

Ports	2011	2013	2015	2017	Ports	2011	2013	2015	2017
Shanghai Port	1.8102	1.8003	1.7942	1.7890	Jiangyin Port	0.2186	0.3716	0.4071	0.4219
Ningbo Zhoushan Port	0.4738	0.6571	0.8267	1.0117	Changzhou Port	0.0984	0.0816	0.1572	0.1923
Jiaxing Port	0.0343	0.5524	0.7357	0.0881	Zhenjiang Port	0.1393	0.2849	0.3182	0.3398
Taizhou Port	0.0367	0.0351	0.4279	0.0531	Yangzhou Port	0.0724	0.1082	0.1179	0.1251
Wenzhou Port	0.0286	0.0313	0.0382	0.0404	Nanjing Port	0.3534	0.5927	0.6833	0.7211
Huzhou Port	0.0992	0.1132	0.0949	0.0851	Ma’anshang Port	0.0357	0.0383	0.0283	0.0279
Lianyungang Port	0.0568	0.0608	0.0752	0.0885	Wuhu Port	0.0289	0.0381	0.0572	0.0646
Nantong Port	0.1744	0.3375	0.3217	0.3575	Tongling Port	0.0091	0.0101	0.0153	0.0190
Suzhou Port	1.1361	1.5382	1.5819	1.6060	Hefei Port	0.0262	0.0468	0.0672	0.0845
Taizhou Port	0.0833	0.1924	0.2518	0.2843

), which are imported into ArcGIS 10.2 software (as shown in Figure 3). The spatial effect of ports in the Yangtze River Delta region in 2011 and 2017 was visualized by using the inverse distance weight spatial interpolation model.

The gap in spatial effect of ports in the Yangtze River Delta region is obvious and the level distribution is shifting from polarization to equilibrium. Among them, the spatial effect of Shanghai Port and Suzhou Port is the most obvious, mainly attributed to the significant advantages of port cities in port and shipping services and the demand for hinterland industries, which forms a collaborative advantage through frequent interaction. However, with the continuous rise of the surrounding ports in recent years, the growth rate of spatial effect between the two has slowed down, verifying that regional port services are more dispersed and port synergy has increased. The spatial effect of Ningbo Zhoushan Port and Nanjing Port increases greatly, among which Ningbo Zhoushan Port has the largest absolute increase. Both have already dominated the port service system with their own advantages. The spatial effect of other ports has been improved, but there is still an absolute gap in the position of branch ports.

Overall, the spatial effect exhibits a block distribution and a trend of extension along two lines. In 2011, two high-intensity concentration points were formed centered around Suzhou and Shanghai and gradually extending to cities such as Changzhou, Jiaxing, Nantong, and Huzhou, indicating that this region is generally strongly served by port services. In addition, the spatial effect of Ningbo Zhoushan Port is also obvious. But at this time, it is still dominated by local hinterland services, with limited regional impact. In terms of other ports, except for Nanjing Port showing a small spatial effect, the service capacity of the Yangtze River Delta port system is still in its infancy. For hinterland cities far away from the ports, the spatial effect of ports extends first along the coastline. Coastal cities such as Yancheng and Taizhou, as well as coastal cities like Shaoxing, Jinhua, and Hangzhou along the Hangzhou Bay, are all affected by port services. This indicates that a significant gap between the core port and branch port space effect makes some regions undergo market segmentation, and the areas with weak port resources are more likely to accept the service of the core port business.

In 2017, the spatial effect of port systems forms a double fan-shaped distribution centered around Shanghai Port and Suzhou Port in the north, and the extension of high-intensity services in the hinterland was more obvious. On the basis of stabilizing the hub position of Shanghai Port, the high-intensity service scope of Suzhou Port was further expanded to Wuxi, Yangzhou, and Ma’anshan. The hub port status of Ningbo Zhoushan Port in the south is further highlighted, and its service capabilities for Shaoxing and Hangzhou are gradually improving. It is worth noting that high-intensity service areas in the hinterland of the southern and northern ports have realized spatial connectivity, indicating that that cooperation between core ports is more obvious in the process of scale expansion. In addition, the low-intensity service areas are more malleable, including central Jiangsu Province, eastern Anhui Province, and the central and western regions of Zhejiang Province. The port service capacity of Taizhou Port and Wenzhou Port in Zhejiang Province and many ports in Anhui Province to the surrounding hinterland still needs to be improved.

5. Conclusions and Prospects

Based on the perspective of spatial effect, the study analyzes regional coordination sustainability of port services in the Yangtze River Delta. Conclusions are as follows. Shanghai Port and Ningbo Zhoushan Port are stronger in the center of the Yangtze River Delta, while Suzhou Port is facing greater expansion pressure. The port score distribution in Jiangsu Province is closer to the average, while Zhejiang Province is more in line with the “center periphery” trend. The overall service potential of ports in Anhui Province to the hinterland is still low.

Spatial gravity between ports forms a semi-circular dense contact zone with the above seaports as the hub and the Yangtze River Delta in China and Zhejiang coastal areas as the boundary. Gravitational connection between Jiangsu and Anhui provinces is more obvious. Decentralized distribution of ports along coast of Zhejiang Province limits connection strength between ports, and cooperation ability in service hinterland needs to be strengthened.

The convenience of port hinterland has changed from location dependence to traffic dependence. The score of Shanghai Port and Ningbo Zhoushan Port has been reduced by influence of the sea orientation. The convenience of the ports in Jiangsu and Anhui provinces is generally higher than that in Zhejiang Province.

Grade distribution of the spatial effect between ports has changed from polarization to equilibrium. Suzhou Port and Shanghai Port are the hub ports, and radiation capacity of Ningbo Zhoushan Port and Nanjing Port is enhanced. The service gap between regions is obvious, but the overall development is more coordinated.

The Yangtze River Delta ports should enhance the overall awareness of serving the region. Against the strategic background of the Yangtze River Delta integration recommended by the national high standard, it should give full play to the inherent advantages of port service in regional resource allocation and promote regional linkage development in the cargo integration of hinterland. It should strengthen port linkage and cooperation and cultivate a more scientific port system. According to the shipping demand of different hinterlands, the service spillover level of Shanghai, Ningbo Zhoushan, and other port groups should be enhanced through enterprise mergers and equity investment, so as to form a more scientific port functional service system. Stakeholders should also actively build branch terminals of Shanghai Port and Ningbo Zhoushan Port, break through the limitation of the Yangtze River Delta in China, and build a more accessible comprehensive shipping service channel. In particular, in-depth cooperation with inland ports in terms of customs clearance mechanism, port cooperation, and river–sea transit should be increased. There may be a focus on supporting construction of ports in northern Jiangsu and southern Zhejiang of China, a plan to lay out the main trunk roads connecting coastal ports with inland hinterland, and enhancing the capacity and sustainability of distributing goods along the line through the opportunity of “one belt and one road” in construction of the passage of land and sea.

Follow-up studies can expand the case objects, conduct in-depth horizontal comparative analysis, and more comprehensively evaluate the degree of port service coordination sustainability in the Yangtze River Delta region to provide support for a high level of service quality.