Marine Ecological Function Zoning and Management Countermeasures: A Case Study of the Sea Area of Zhejiang Province

Abstract

The contradiction between the development of marine resources and ecological protection in Zhejiang is prominent, which restricts the high-quality and continuous supply of marine ecological products. As a result, the efficient maintenance of the ecological security pattern of inshore waters relies on the scientific division of marine ecological function zones and the management and maintenance of zoning areas. This paper constructs a technical framework for marine ecological function zoning from the aspects of marine ecosystem health, marine ecosystem diversity and economic and social development balance using GIS-based overlay analysis and the three-dimensional matrix discriminant model to divide marine ecological function zones in the managed waters of Zhejiang Province. The results indicate that the managed sea areas in Zhejiang Province are divided into ten marine ecological function areas, including three marine ecological supply areas (54%), four marine mariculture and resting areas (24%) and three marine ecological restoration areas (22%). As per the zoning results of the marine ecological function, this study further proposes protection and management strategies for different zoning units, in the hopes of providing technical support and practical reference for the division and management of marine ecological function areas in other sea areas.

1. Introduction

The ocean is not only a precious natural resource, but also an important living space for human survival and development. With the development of science and technology in recent years, the Earth has been a witness of an increased consumption rate of terrestrial resources, making people gradually turn their attention to the ocean as a huge treasure and begin to vigorously develop and utilize marine resources. Nevertheless, the overdevelopment of marine resources has led to increasingly prominent marine environmental problems. The rational utilization of marine resources, protection of the marine ecological environment and promotion of sustainable marine economic development have become significant issues for China’s marine ecological environment management [1]. The National Ecological Function Regionalization (Revised Edition) [2], jointly issued by the Ministry of Environmental Protection of China and the Chinese Academy of Sciences in 2015, pointed out that ecological function regionalization is a process of dividing ecological function areas on the basis of a full understanding of the structure, the process of the ecosystem and the differentiation rule of the ecosystem service function space. The definite guarantee of areas of great significance to national ecological security can provide a reference for our country’s ecological protection and construction, the orderly development of natural resources and the rational layout of industries, in addition to providing impetus for the coordinated and favorable development of our country’s economic, social and ecological protection.

However, there are still some challenges in our country’s marine zoning protection system. Before the implementation of territorial spatial planning, our country’s protection system for zoning areas of marine space was constructed based on protected marine areas in the marine functional zoning system [3]. The correct and reasonable utilization of ocean areas can be realized through the ocean spatial pattern constructed by ocean zoning areas [4,5]. The proposal of management requirements for ocean utilization and requirements for marine environmental protection reflects the role played by functional management and control [4]. With the gradual implementation of territorial spatial planning, the optimized protected marine areas will be incorporated into the natural protection area system and the marine ecological red line system to achieve the protection of specific sea areas [5]. At present, the planning scheme for sea area space implemented in my country has accomplished the efficient utilization of marine resources and marine environmental protection to a certain extent. The protection of the marine ecological environment can be attained through the establishment of protected marine areas, prohibited development areas and red line areas for ecological protection [6]. Nevertheless, this reflects that the protection system of marine spatial zoning currently implemented in my country is a specific marine space delineated for protection objects, while ignoring the integrity, connectivity and systematisms of marine ecosystems. On the basis of the zoning system for marine ecological elements in the whole sea area, the necessity of human survival and development ought to be considered when analyzing the systematic development of marine ecological elements as well. Consequently, it is particularly crucial to establish a plan for the development and protection of zoning areas based on marine ecological protection in the whole sea area.

The marine economy serves as an advantage to Zhejiang Province. In 2020, the province’s GOP reached CNY 920 billion, an increase of 48.9% over the CNY 618 billion in 2015, and its proportion in the province’s GDP remained above 14%, 4 to 5 percentage points higher than the national average [7]. However, with the continued rapid development of the marine economy and the acceleration of urbanization, the inshore waters of Zhejiang Province have also been affected by human activities. For instance, landfill pollutant discharging into the sea, marine engineering, transportation and marine aquaculture. Social and economic development has led to the shrinkage of the ecological space of inshore waters, the reduction of natural coastlines, the overload of environmental carrying capacity, the serious damage to marine ecological functions and the intensification of marine ecological risks [8]. In the context of rapid social and economic development in Zhejiang Province, the marine ecological environment should indeed be identified and delimited properly for protection, and the areas that should be governed effectively are of great significance. As a result, this paper establishes the technical zoning system and zoning management objectives of marine ecological function areas at the provincial space scale of sea area through analyzing the marine ecological characteristics and focusing on the service functions such as material production, biodiversity maintenance and blue carbon sink carried by the ocean. Moreover, empirical research was carried out within the inshore waters of Zhejiang Province as the research area for the purpose of providing a scientific basis for guiding marine ecological environment protection and resource development and utilization.

2. Summary of the Research

Zhejiang Province is located in the south wing of the Yangtze River Delta and borders the East China Sea to the east, Fujian to the south, Jiangxi and Anhui to the west and Shanghai and Jiangsu to the north. The area of water and territorial sea in Zhejiang Province is about 44,000 km², and the total length of the coastline is approximately 6600 km (including the coastline of the island), therefore making its rank first in the country. With the core geographical superiority of the “T”- shaped economic belt and the world-class urban agglomeration in the Yangtze River Delta, the coastal areas of Zhejiang are the hubs of river–sea intermodal transportation internally, and the bridges connecting the Circum-Bohai Sea Economic Zone and the Pearl River Delta Economic Zone. Externally, it is strategically adjacent to the international shipping corridor. As a result, it occupies a pivotal position in our country’s open pattern. Apart from the suitable natural environment and abundant natural resources, the coastal areas of Zhejiang are rich in resources such as ports, fisheries, tourism, tidal flats, islands and marine energy, which provide superior location advantages and sufficient resources for accelerating the province’s marine economic development and building a powerful marine province.

The inshore waters of Zhejiang Province are subject to intensive marine development activities and embrace a variety of sea-use types. As of October 2018, the sea area of Right in Zhejiang Province has exceeded 550 km², most of which are concentrated in the sea area with a water depth of 30 m and shallower. Concurrently, 18 national and provincial marine-protected regions have been built in the waters of Zhejiang Province, with a total area of about 4000 km². Moreover, the sea area designated as the red line for marine ecological protection reaches 1.4 × 10⁴ km², accounting for 31.72% of the sea area managed by Zhejiang Province [7]. Consequently, conflicts between marine production space, living space and ecological space will inevitably occur in the process of the development and utilization of sea areas in Zhejiang Province, and require proper coordination. It is crucial and realistic to adopt zoning marine ecological function areas, taking this sea area as a case.

The evaluation scope of this study was divided in the jurisdictional sea area using a standard grid, in accordance with the standard demarcation mesh method, and the length of the coastline or the different requirements for the sea area. This study divides the sea area under the jurisdiction of Zhejiang Province into several km grids (1 × 1 km) as evaluation units according to the continental coastline length and jurisdictional area of Zhejiang Province (Figure 1).

3. Data and Research Methods

3.1. Research Framework

This paper proposes the technical zoning method of marine ecological function areas, with National Ecological Function Regionalization as a reference. This paper takes the following measures to carry out the zoning of marine ecological function areas: (1) After combining the natural attributes of the sea area in the study area, key characteristics of marine ecology and the social and economic development of adjacent land areas and ecosystem survey data, an evaluation index system is established by the confirmation of dominant ecosystem function types that require assessment and analyzing. (2) The spatial distribution of each indicator is obtained through a standard kilometer grid (1 × 1 km) used as the evaluation unit, and spatial interpolation and grid processing based on ArcGIS 10.7 software. (3) The equal area method is adopted to divide the normalized evaluation indicators into three grades: low, medium and high. (4) A three-dimensional discriminant matrix is used to divide preliminary discriminant results marine ecological function areas. (5) The ultimate zoning plan is drawn up as per expert opinions, policies for marine ecological and environmental protection and the relationship between the overall utilization and protection of marine resources. The technical roadmap is shown in Figure 2.

3.2. Indicator System and Data Sources

The delineation of marine ecological function areas is based on a set of indicator systems, consisting of target aspect (A), standard aspect (B) and indicator aspect (C), aiming to characterize the dominant ecological functions of various sea area units.

With regard to marine ecosystem health, the concentration of chlorophyll a (C1) and the water quality environment (C2) were selected as evaluation indicators. The concentration of chlorophyll a is a parameter of marine primary productivity [9], which can reflect the supply capacity of the research sea area. As a parameter of the quality of the living environment, the water quality environment can reflect the quality of seawater in the sea area.

With respect to marine ecosystem diversity, phytoplankton diversity (C3), zooplankton diversity (C4), the macrobenthic biodiversity of shallow seas (C5) [10] and ecosystem type (C6) were selected as evaluation indicators [11]. The diversity of phytoplankton is crucial to the stability of the community structure, which reflects the unique species composition and individual density characteristics of the community. Zooplankton diversity can better reflect the purification efficiency of seawater. The macrobenthic biodiversity of shallow seas can reflect the changes of the marine ecological environment and accurately reflect the long-term changes of the habitat environment, so it has been widely used in the assessment of the ecological environment quality of coastal zones. Ecosystem types reflect the synergistic relationship between the interaction of different biological communities and the inorganic environment. The ecosystem types in this paper include important coastal wetlands, specially protected islands and important estuarine ecosystems. The closer to the above ecosystem types, the larger the ecosystem type index. Swimming animals, bacteria and other related indicators were not selected for the evaluation of marine ecosystem diversity because of the availability of data.

$$D_{{ }_{\mathrm{i}}}={\displaystyle \sum _{i,j=0}^n\frac{1}{{\left\{d_{ij}\right\}}_{\min }}}$$

(1)

In the formula, D_i is the distance index of ecosystem type and d_ij is the distance between the center of the ith assessment unit and the jth ecosystem type.

With regard to the discussion of the balance of economic and social development, data such as per capita GOP (C7), the investment in fixed assets of the whole society in adjacent land areas (C8) and the employment in adjacent land areas (C9) were selected for research. Among them, the per capita GOP reflects the development of the marine economy, and the investment in fixed assets of the whole society in adjacent land areas demonstrates the scale, speed, proportional relationship and direction for utilization of fixed asset investment in adjacent land areas. Affected by the economic structure and economic growth model, employment in adjacent land areas reflects economic development [12].

The data used in this study are derived from the biological data of various marine areas in Zhejiang Province downloaded from the National Oceanic Data Center, and the interpolation of sampled data obtained from the environmental survey of sea-related projects in Zhejiang Province. Moreover, the map data were registered and vectorized through ArcGIS software. Data such as per capita GOP, investment in fixed assets of the whole society adjacent to the land area and the employment in adjacent land areas were obtained from the 2018 China Marine Statistics Yearbook and the 2018 China County Statistics Yearbook. The name, time and data source of each indicator are listed in

Table 1. Index system and data sources.

Target Aspect	Standard Aspect	Indicator Aspect	Date	Data Source
Health of the marine ecological environment	Supply capacity	C1 Concentration of chlorophyll a	February 2020	National Marine Data Center (Statistics) http://mds.nmdis.org.cn/pages/home.html, (accessed on 11 December 2020)
	Survival conditions	C2 Water quality environment	2017	2017 Ecological Environment Quality Bulletin of China’s Inshore Waters (grid picture)
Diversity of marine ecosystem	Biodiversity	C3 Phytoplankton diversity	2018	Environmental investigation and sampling of sea-related projects in Zhejiang Province (Sampling statistics)
		C4 Zooplankton diversity	2018	Environmental investigation and sampling of sea-related projects in Zhejiang Province (Sampling statistics)
		C5 Diversity of macrobenthos in shallow seas	2018	Environmental investigation and sampling of sea-related projects in Zhejiang Province (Sampling statistics)
	habitat diversity	C6 Ecosystem type	2018	Environmental Investigation of Sea-related Projects in Zhejiang Province (Vector Data)
Balance of economic and social development	Economic growth	C7 per capita GOP	2017	2018 China Marine Statistics Yearbook (Statistics)
	Social development	C8 Investment in fixed assets of the whole society adjacent to the land area	2017	2018 China Marine Statistics Yearbook (Statistics)
		C9 Employment adjacent to land areas	2017	2018 China County Statistics Yearbook (Statistics)

. The values and the high, medium and low level range of indicators are shown in

Table 2. Index value ranges and attributes.

Serial Number	Indicator Aspect	Unit	Range of Values	High	Medium	Low
C1	Concentration of chlorophyll a	μg/L	0.54–3.20	2.00–3.20	1.26–1.99	0.54–1.25
C2	Water quality environment	dimensionless	1–5	1–2	3–4	5
C3	Phytoplankton diversity	dimensionless	0.50–3.02	2.09–3.02	1.39–2.08	0.50–1.38
C4	Zooplankton diversity	dimensionless	0.78–3.59	2.68–3.59	1.85–2.67	0.78–1.84
C5	Diversity of macrobenthos in shallow seas	dimensionless	0–2.87	2.03–2.87	1.23–2.02	0–1.22
C6	Ecosystem type	km	0–90,948.86	0–20,329.75	20,329.76–43,512.79	43,512.80–90,948.86
C7	per capita GOP	CNY million	0.10–0.90	0.51–0.90	0.31–0.50	0.10–0.30
C8	Investment in fixed assets of the whole society adjacent to the land area	CNY million	1450.31–5009.58	4995.63–5009.58	2999.65–4995.62	1450.31–2999.64
C9	Employment adjacent to land areas	CNY million	23.14–183.1	132.92–183.10	108.46–132.92	23.14–108.45

.

3.3. Evaluation Method

3.3.1. Identification of Zoning Units

The index system is constructed from three aspects of marine ecological environment health, marine ecosystem diversity and the balance of economic and social development in adjacent land areas through learning from the definition of ecological function area in National Ecological Function Regionalization and combining the natural attributes and ecological attributes of marine resources, forming three major functional areas: the marine ecological restoration area, marine ecological supply area and marine mariculture and resting area.

• Marine ecological supply area: It refers to an area that is rich in marine ecological environment resources and strong carrying capacity. The primary management and control objectives of this area are to protect biodiversity, including national and provincial marine nature reserves, ensure the supply of marine materials and ecological products and protect marine areas and uninhabited islands with marine ecological functions such as fishery resources, marine ecological environment and marine biodiversity.
• Marine mariculture and resting area: It refers to the marine ecological environment with high development suitability, including the sea area suitable for human life, health preservation and recreation and uninhabited islands.
• Marine ecological restoration area: It refers to an area with poor marine ecological environment resources, weak carrying capacity and damaged ecological environment. The primary goal of this area is ecological restoration.

3.3.2. Three-Dimensional Discrimination Matrix

The three-dimensional discrimination matrix of marine ecological function areas is set according to the basic connotations of marine ecological support areas, marine mariculture and resting areas and marine ecological restoration areas, in addition to the relationships between the health of the marine ecological environment, the balance of economic and social development and the diversity of the marine ecosystem.

The principle for delimiting the three-dimensional matrix is that areas with high and medium levels of health of the marine ecosystem are classified as marine ecological supply areas; areas with low levels of health of marine ecosystem are classified as marine ecological restoration areas and areas with a high diversity of the marine ecosystem and a good balance of economic and social development are classified as marine mariculture and resting areas.

The type of marine ecological function area of each evaluation unit is determined based on the evaluation criteria of the three-dimensional discrimination matrix, resulting in preliminary discrimination results of marine ecological supply areas, marine mariculture and resting areas and marine ecological restoration areas.

3.3.3. Determination of the Division Plan

The preliminary discrimination results reflect the natural characteristics of the basic functions of the marine ecological environment but cannot fully express the actual management needs. The following three aspects should be considered when dividing marine ecological functional areas: Firstly, the principles of promoting the national strategy should be followed to ensure the smooth implementation of the national marine ecological environment protection policy. Secondly, the relationship with the overall layout of land and space planning should be coordinated, and a development pattern in which the ocean and land resources and environment are coordinated, and economic and social development are positively interacted, should be established. Thirdly, the relationship between the resource utilization and pattern protection of the sea area should be coordinated. Accordingly, the type of marine ecological function regionalization was eventually determined, combined with the result judged by the three-dimensional discrimination matrix as the preliminary result, as well as the opinions of management and experts.

4. Results and Management Strategy

4.1. Indicator Normalization

ArcGIS-based spatial superposition analysis is employed to generate evaluation results after the evaluation indicators of marine ecological function areas have been standardized and counted based on zoning units. Among them, positive indicators are standardized according to Formula (2), and negative indicators are standardized according to Formula (3). The spatial distribution of each indicator is shown in Figure 3.

$$X_{{ }_{positive}}=\frac{X-X_{\min }}{X_{\max }-X_{\min }}$$

(2)

$$X_{{}_{negative}}=\frac{X_{\max }-X}{X_{\max }-X_{\min }}$$

(3)

In the formula, X symbols the indicator value and X_positive and X_negative are the index normalization results; X_max is the maximum value in the indicator and X_min is the minimum value in the indicator.

4.2. Indicator Weight

To evaluate the weights of each index, AHP is used. Based on the AHP principle [13,14], the 9-scale method is adopted to first establish the discriminant matrix of the index from the first-level target aspect, before establishing the discriminant matrix from the second-level index aspect. Ultimately, the indicators at all levels are compared on the importance of pairs (

Table 3. Comparison matrix of target level index system.

Target Aspect	Health of the Marine Ecological Environment	Diversity of the Marine Ecosystem	Balance of Economic and Social Development
Health of the marine ecological environment	1	3	2
Diversity of the marine ecosystem	1/3	1	2
Balance of economic and social development	1/2	1/2	1

and

Table 4. Comparison matrix of index level index system.

Indicator Aspect	Concentration of Chlorophyll a	Water Quality Environment	Phytoplankton Diversity	Zooplankton Diversity	Diversity of Macrobenthos in Shallow Seas	Ecosystem Type	Per Capita GOP	Investment in Fixed Assets of the Whole Society Adjacent to the Land Area	Employment Adjacent to Land Areas
Concentration of chlorophyll a	1	1/2	-	-	-	-	-	-	-
Water quality environment	2	1	-	-	-	-	-	-	-
Phytoplankton diversity	-	-	1	3/2	3	1	-	-	-
Zooplankton diversity	-	-	2/3	1	2	2/3	-	-	-
Diversity of macrobenthos in shallow seas	-	-	1/3	1/2	1	1/3	-	-	-
Ecosystem type	-	-	1	3/2	3	1	-	-	-
Per capita GOP	-	-	-	-	-	-	1	3/2	3
Investment in fixed assets of the whole society adjacent to the land area	-	-	-	-	-	-	2/3	1	2
Employment adjacent land areas	-	-	-	--	-	-	1/3	1/2	1

). After obtaining the largest eigenvalue of the discriminant matrix and its corresponding eigenvectors, the obtained eigenvectors are normalized to obtain the weight composition vector of each evaluation factor. If the calculated consistency scale coefficient is less than 0.1, the discriminant matrix satisfies the consistency test standard and obtains the corresponding weight. Otherwise, the matrix is judged to be inconsistent, and the discriminant matrix needs to be reconstructed until the consistency coefficient is less than 0.1. In this study, the consistency coefficient of the target layer judgment matrix is 3.8 × 10⁻¹⁶, and the consistency coefficient of the discriminant matrix from the index aspect is 0, 6.8 × 10⁻⁴, 4 × 10⁻⁴, showing that the matrix meets the consistency test. The following results are obtained (

Table 5. Index system and weight.

Serial Number	Target Aspect	Indicator Aspect	Weight
C1	Health of the marine ecological environment	Concentration of chlorophyll a	0.132
C2		Water quality environment	0.268
C3	Diversity of the marine ecosystem	Phytoplankton diversity	0.132
C4		Zooplankton diversity	0.088
C5		Diversity of macrobenthos in shallow seas	0.048
C6		Ecosystem type	0.132
C7	Balance of economic and social development	per capita GOP	0.1
C8		Investment in fixed assets of the whole society adjacent to the land area	0.066
C9		Employment adjacent to land areas	0.034

).

4.3. Analysis of Zoning Results

The delineation results of marine ecological functional areas in Zhejiang Province based on GIS and a 3D matrix discriminant model are shown in Figure 4. As is visible from the figure, the sea areas managed by Zhejiang Province are divided into 10 marine ecological function areas, including marine ecological supply areas, 3 marine ecological restoration areas each and 4 marine mariculture and resting areas. Among them, the area of the marine ecological supply area is 23,453 km², accounting for 54%, the area of the marine mariculture and resting area reaches 10,687 km², accounting for 24%, and the area of the marine ecological restoration area occupies 22 km², accounting for 24%. The zoning results indicate that the marine ecological restoration areas are mainly distributed in Hangzhou Bay, Yueqing Bay and Taizhou Bay, the marine ecological supply areas are primarily distributed in the offshore areas with better marine ecological health and the marine mariculture and resting areas are distributed in the sea area with the Putuo Mountain as the core, the inshore waters of Wenling City and the inshore waters of Cangnan County. In general, Zhejiang Province is facing a fragile marine ecological environment, low-quality ecosystems and functions, a still severe ecological security situation and outstanding contradictions between marine ecological protection and utilization.

4.4. Analysis of Zoning Effectiveness

To illustrate the rationality of the zoning system, this paper seeks to compare and analyze some regulations related to marine ecological zoning issued by the state and local governments and the explanatory documents on the situation of marine ecological zoning. In accordance with the Technical Instructions for the Management and Control of Ecological Environment Zoning in the Inshore Waters [15] and following the principle of “Three Lines and One Order” issued by the Ministry of Ecology and Environment of the PPC, the ecological environment control area is divided into priority protected areas, key protected areas and general control areas. Priority protected areas focus on maintaining ecosystem health and biodiversity. Key protected areas concentrate on areas with serious development damage such as semi-enclosed bays and substandard water quality. The general management area focuses on maintaining the quality of the marine ecological environment and combining the sea-use methods to determine the corresponding management measures. Marine ecological suitability is evaluated from three aspects: marine ecological environment suitability, marine natural resource suitability and marine social and economic suitability, according to the Technical Guidelines for Marine Ecological Suitability Evaluation issued by Zhejiang Province [16]. The quality of the marine ecological environment is the determinant for the need for marine ecological restoration in the region. The abundance of marine natural resources affects the regional marine material supply and ecological product supply capacity. The function positioning of marine ecological supply areas and the marine socio-economic suitability reflect the suitability of human beings to live, preserve health and rest in the area. The above regulations and explanatory documents are basically consistent with the zoning idea of this study, so the zoning type of marine ecological functions constructed in this paper is reasonable.

To further illustrate the rationality of the evaluation results, this paper seeks to compare the zoning results of marine ecological functional areas with the Marine Functional Regionalization of Zhejiang Province [17]. As a crucial basis for the management department to approve the development of marine space, the Marine Functional Regionalization of Zhejiang Province divides the study area into fishery area, transportation area, protected area, reserved area, industrial area, etc., and puts forward specific control requirements for each functional area. Primarily distributed in agricultural and fishery areas, the marine ecological supply area’s primary function is to increase the aquaculture of fishery resources, which is in line with the positioning of the marine ecological supply area to protect biodiversity and ensure the reserve function of marine aquatic products. Marine mariculture and resting areas are primarily included protected areas, tourism, leisure and entertainment areas. Among them, the protected area promotes the coordinated development of marine ecological protection and the development and utilization of surrounding sea areas without changing the natural attributes of the sea area and affecting the ecological environment of the sea area. This is in line with the development location of ecotourism suitable for humans to live, preserve health and rest in the marine mariculture and resting area. The marine ecological restoration area mainly covers the coastal industrial and urban marine areas. Attention should be paid to the intensive development of sea areas and the low-carbon and circular development of the marine economy, improving the quality of coastal habitats. Therefore, the zoning results are basically consistent with the functional positioning and management requirements of the areas described in the Marine Functional Regionalization of Zhejiang Province.

4.5. Management Strategy

• Marine ecological supply areas are primarily used to carry out sea-use activities for the development and conservation of fishery resources. In addition, they are also used to develop modern fisheries that ensure the supply of marine materials and ecological products. Activities that damage aquatic living resources and pollute the water environment within the specified marine ecological supply area are prohibited. The sea-use projects that fail to meet the requirements of zoning management in this area should be gradually adjusted. On the other hand, the sea areas with substandard environmental quality should be improved, and the damaged coasts, estuaries and other ecosystems in the area should be restored, aiming to protect fishery resources and important fishery waters such as spawning grounds, wintering grounds, bait farms and migratory passages.
• Marine mariculture and resting areas are mainly used for humans to live, preserve health and rest. In accordance with the requirements of centralized and intensive sea use, the use efficiency of marine space resources in this area should be improved, ecological environmental protection measures should be strictly implemented and coastal natural landscapes and beach resources should be protected to dodge the negative impact of human activities on the marine ecological environment. The scale of the development and construction of marine mariculture and resting areas should be rationally controlled, the spatial layout of the area should be optimized and crucial ecological resources such as coastlines, bays and islands appropriately utilized. Coastal restoration work in the waters around towns should be carried out to build new marine mariculture and resting areas
• The supervision and environmental monitoring of sea-use activities in the marine ecological restoration area ought to be strengthened. Strict restrictions should be placed where sea-use activities affect and interfere with the protected objects in the marine ecological restoration area. The marine ecological environment and biodiversity should be maintained, restored and improved. The natural landscape should also be protected, and protection measures need to be improved. The monitoring and management of the operation quality of the marine ecological restoration area require strengthening and the unreasonable sea-use projects in the area should be regulated, while the damaged marine ecosystem should be restored.

Additionally, to avoid the loss of basic functions of functional areas caused by human activities, this study determines the protection objects of each marine ecological functional area based on the distribution characteristics of marine organisms, ecological function positioning and ecological environment quality in Zhejiang Province, and guides the development direction of functional areas (

Table 6. Information table of marine ecological function zoning in Zhejiang Province.

Function Code	Type of Function Area	Protected Target	Development Direction
A-1	Marine ecological supply areas	Aquatic genetic resources	Focus on ensuring the functions of fishery sea use and fishing sea use. On the premise of not affecting the basic functions of agriculture and fishery, the sea uses for transportation and tourism and entertainment can be compatible, and it is forbidden to change the natural attributes of the sea area.
A-2	Marine ecological supply areas	Important habitats for marine organisms and their birds, and living environment of macroalgae, thick-shelled mussels and striped mussels	Continue to restore important habitats of marine life and its birds to maintain a positive development direction. After the ecosystem is stabilized, the cultural tourism function can be properly released, promoting the gradual transformation of zoning areas into mariculture and resting areas.
A-3	Marine ecological supply areas	Marine geology and landform landscape, coastal organisms, marine biodiversity, important shellfish and algae	Protect the marine geology and landform landscape, continue to restore the biological and marine biodiversity of the coastal zone, realize the sustainable development of the island’s ecological environment and maintain the positioning of the ecological supply area.
B-1	Marine ecological restoration areas	Important habitats of marine organisms	Steadily achieve the restoration of marine biodiversity according to the requirements of the repair object. After achieving the goal, its cultural tourism function should be gradually released and its transformation into a marine mariculture and resting area should be promoted positively.
B-2	Marine ecological restoration areas	Marine biodiversity	Steadily achieve the restoration of marine biodiversity according to the requirements of the repair object. After achieving the goal, its cultural tourism function should be gradually released and its transformation into a marine mariculture and resting area should be promoted positively.
B-3	Marine ecological restoration areas	Comprehensive management of marine environment	Comprehensively improve the bay ecosystem, estuary wetland ecosystem, coastal habitat and its landscape to achieve the significant restoration of ecological functions in Taizhou Bay, obvious positive development of the estuary wetland ecosystem and significant improvement in coastal habitat quality.
C-1	Marine mariculture and resting areas	Develop culture, entertainment, religion and tourism industries with Mount Putuo as the core	Drive the development of the island’s cultural tourism industry and maintain a well-developed marine ecological environment.
C-2	Marine mariculture and resting areas	Coastal tourism	Drive the development of coastal tourism and maintain the continuous development of the marine ecological environment.
C-3	Marine mariculture and resting areas	Coastal tourism	Drive the development of coastal tourism and maintain the continuous development of the marine ecological environment.
C-4	Marine mariculture and resting areas	Coastal tourism	Drive the development of coastal tourism and maintain the continuous development of the marine ecological environment.

). As is visible from the table, the development goals of some functional areas have changed to the function of marine mariculture and resting areas, therefore aiming to form marine ecological restoration areas, marine ecological supply areas and marine mariculture and resting areas with an area ratio of 1:2:6. Coastal ecological development, aquaculture construction and environmental restoration should be comprehensively considered, establishing an eco-friendly development model of the sea area.

5. Discussion

Compared to the ecological function regionalization of the land area [18,19,20,21,22,23,24,25,26], the research on marine ecological function regionalization has received less attention. Research on marine spatial planning and management concentrating on typical marine ecosystems has become mainstream in the international field, mainly focusing on biologically and ecologically vital areas [27], assessment maps of marine biological value [28,29], key ecological areas [30,31], biodiversity conservation priority areas [32], hotspots [33] and other fields. Gilliland formulated marine spatial planning indicators and technical processes based on ecosystems [34], while Crowder studied the intrinsic connection between marine spatial planning and management on the basis of ecosystems [35]. Chassot, E. is based on the classification indicators of ecosystem structure, and screens them according to the marine ecological function information reflected by each indicator and obtains the zoning results through spatial clustering [36]. Most of the relevant research in our country concentrates on terrestrial and freshwater waters. Song Xiaoye et al. proposed three development directions for the future of ecological function regionalization: implement systematic research on the ecological function regionalization of basin water, deepen research on the application of ecological function regionalization and conduct additional education for users or potential users engaging in ecological function regionalization [37]. Xiongwei established various spatial scales and various types of classification systems for regional ecological spaces and classified and managed these systems in a targeted manner. Xu Baiqi used watershed as the basic unit for dividing ecological function areas [38]. Lu Qiaomei suggested that comprehensive environmental management should be incorporated into the system for dividing county-level ecological environment function areas [39]. Xu Yan et al. [40] took Changxing Island as an example to carry out research on small-scale marine ecological function regionalization. Nevertheless, there remains a lack of a technical method systems for zoning and case studies on broadscale spatial scales. At present, the limited understanding of the importance of marine ecological protection and the lack of ecological theoretical support have resulted in great conflicts between marine production space, living space and ecological space, making it difficult to efficiently build marine ecological civilization.

This paper combines the characteristics of marine ecosystem integrity, connectivity and the systemic characteristics of marine ecosystems, as well as the whole sea area division system of marine ecological elements, and considers the necessity of human survival and development when analyzing the development system of the marine ecological element, thus bringing a general direction aimed at protecting the priority development and conservation functions of zoning areas of the whole sea area. This paper’s objective is to provide a scientific basis for formulating plans of regional marine ecological environment protection and ecological construction, maintaining regional marine ecological security, promoting the rational utilization of marine resources, forming industrial production layouts and protecting the marine ecological environment of conservation areas.

Nevertheless, the following deficiencies remain existent in this paper:

• Based on the spatial differentiation theory, this study’s focus is on the zoning system for marine ecological elements of the whole sea area, mainly selecting indicators from the perspectives of ecological environment elements, ecological environment sensitivity and ecological service functions. In addition, it also comprehensively evaluates the sea area from three aspects: marine ecosystem health, marine ecosystem diversity and the balance of economic and social development. At the same time, this study considers the necessity of human survival and development when analyzing the systematic development of marine ecological elements, a supplement to the spatial planning of marine resources in national ecological function regionalization. However, the quantitative analysis does not address the functioning of our country’s inshore ecosystem services.
• Combined with the characteristics of marine ecosystem integrity, connectivity and systemization and current marine management experience, this study proposes that marine ecological function zones should be divided into first-level functional zones and second-level functional zones. This paper focuses on the exploration of the zoning structure of the first-level marine ecological function and does not conduct research on the zoning type of the second-level marine ecological function.
• Since the marine ecological function zoning in this study is only for the sea area, it is recommended to refer to the National Ecological Function Regionalization for the ecological function zoning of islands and continents.

6. Conclusions

As a result of the increase in demand for marine development in Zhejiang Province, the contradiction between the development and protection of marine resources has become increasingly significant, posing new challenges to the coordinated and orderly development of marine ecological environment protection and construction. This paper constructs the index system of marine ecological function zoning in Zhejiang Province based on the actual situation of the marine ecological environment and utilization in Zhejiang Province. This was after a full consideration of the coordination between ecological environment protection and development. This paper also optimizes and improves the current ecological zones based on qualitative ocean data and sets a three-dimensional discriminant matrix divided in accordance with the type of marine ecological functional area, thus effectively avoiding the influence of subjective factors on the index. Relying on the comprehensive consideration of the matching and contrasting relationship between marine ecological environment health, balanced economic and social development and marine ecosystem diversity, the method can identify marine ecological supply areas, marine mariculture and rest areas and marine ecological restoration areas against the background of high-intensity marine development. Consequently, it provides a scientific basis for formulating plans for regional environmental protection and construction, maintaining regional ecological security, promoting the rational development and utilization of resources and forming production layout, as well as protecting the marine ecological environment in conservation areas.

The area of marine ecological supply areas in the managed sea areas of Zhejiang Province accounts for 54%, the area of marine mariculture and rest areas makes up 24% and the area of marine ecological restoration areas occupies 22%. To avoid industrial sea-use conflicts in inshore waters, the deep-water offshore areas in marine ecological supply areas should be prioritized for development with respect to the coordinated development of marine ecological protection and utilization in Zhejiang Province. Marine mariculture and resting areas should adhere to the eco-friendly sea area development model. Ecological protection and landscape protection require to be considered together as a result of high ecological vulnerability value and landscape resource value kept in the marine ecological restoration area. The cultural and tourism function should be properly released after the ecosystem of some marine ecological restoration areas is stabilized, promoting the gradual transformation of planning areas into mariculture and resting areas.