1 Introduction

Since the 1990s, the world economy has grown rapidly, and the marine economy has become a new growth point for regional economic development (Zhong, 2021). In May 2001, the United Nations treaty document stated that ‘the twenty-first century is the century of the sea’. Nearly 60% of the world's total economic output is contributed by the coastal ports and their hinterlands of the world's economies. In this process, the level of human development and use of the ocean is constantly improving, and problems such as marine environmental pollution and overexploitation of marine resources are persistent (Zhang et al., 2020). In 2015, the United Nations General Assembly’s seventh session adopted the ‘2030 Agenda for Sustainable Development’, which urges all countries to achieve several sustainable development goals, including ‘protecting and sustainable use of the oceans and marine resources to promote sustainable development’. The 2022 World Summit on Sustainable Development and the 2012 Rio + 20 Summit further advanced sustainable development into global action. With the global understanding of the concept of sustainable development and the clear practice of the world's marine economy, researchers have extensively studied sustainable development of the marine economy and created a knowledge graph and research system in its dynamic development process.

Among these, addressing the problems in the development of the marine economy, finding a scientific sustainable development plan, and promoting the healthy development of the marine economy have received much academic attention (Zhu, 2021). Due to time constraints or limited analytical perspectives, earlier studies failed to fully extract the experience, achievements, and contributions of research on the sustainable development of the marine economy and lacked exploration and prospects for new trends. This study quantifies and highlights the literature on the sustainable development of the marine economy since 1994 and comprehensively classifies the thematic lineage, characteristic evolution, hotspot tracking, and trend outlook of the studies from a qualitative perspective to provide a useful reference for future research on the promotion of the high-quality development of the marine economy.

2 Data source collection

The World Commission on Environment and Development defines sustainable development as ‘development that meets the needs of the present without compromising the ability of future generations to meet their own needs’. It is an integrated and dynamic concept involving economy, society, culture, technology, and natural environment. The fundamental purpose of sustainable development of the marine economy is to support the development of the national economy and society and continuously contribute to building a strong marine economy. Accordingly, we gathered articles from the Chinese Social Science Citation Index Database and Web of Science Core Collection Database with topics on ‘marine economy sustainable’, ‘marine economy sustainability’, ‘ocean economy sustainable’, and ‘ocean economy sustainability’. In 1994, China's State Council adopted the ‘China 21 Century Agenda’, which laid out the overall strategic framework for China's sustainable development; therefore, the publication year is limited to 1994–2023. Excluding invalid data such as low relevance to the topic, journal, conference call for papers, volume headings, introduction of personal academic achievements, book reviews, missing author details, and duplicates, we finally obtained 1186 articles, in which 366 articles were from CNKI and 232 articles from WOS. The articles examined in this study is closely related to sustainable development. It presents a macroscopic view of the studies on sustainable development of marine economy for China and other countries.

2.1 The annual trend of publications

Figure 1 shows the distribution of annual research publications. Little relevant literature was published before 2000, and the number of publications fluctuated between 2000 and 2012. China’s Ocean Agenda 21 was proposed in 1996 as a strategy for sustainable development of its ocean industry. In 2003, the National Ocean Economy Development Planning Outline emphasized the need to strengthen the coordination, management, and support of ocean economy development planning. In 1992, the United Nations Conference on Environment and Development adopted Agenda 21. In 1994, the 49th General Assembly of the United Nations declared 1998 the International Year of the Ocean to highlight the importance of oceans, marine environment, marine resources, and sustainable development to the world. After 2012, the number of studies fluctuated steadily, and the annual number of published articles remained relatively flat in China, while those published in other countries increased rapidly and far exceeded that of China. In 2012 the United Nations Conference on Sustainable Development was held in Rio de Janeiro. It proposed the concept of a blue economy focused on marine sustainable development. Since then, sustainable development of marine economy has been hotly debated. Similarly, the 2017 ‘Sustainable Development Goals Report’ proposed by the United Nations has drawn broader attention to this topic.

Fig. 1
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Annual number of publications on research on the sustainable development of the marine economy (1994–2023)

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2.2 Major research institutions

CiteSpace software was used for statistical analysis of the institutions publishing literature on the cooperation between research institutions and their contribution to the sustainable development of marine economy (Figs. 2, 3 and 4). Figure 2 shows 302 nodes, 171 connections, and a network density of 0.0038. Figure 3 shows 186 nodes, 259 connections, and a network density of 0.0151. Figure 4 shows 366 nodes, 647 connections, and a network density of 0.0097. The larger font size of the research institution’s name in the graph indicates how often the institution has published articles. A combination of the map and frequency table of publishing institutions (Table 3 in Appendix 1) shows that Liaoning Normal University and University of Tasmania have the highest number of publications; however, their research directions are varied. For example, the Research Center for Marine Economy and Sustainable Development of Liaoning Normal University and the School of Economics of Ocean University of China are both outstanding in marine economy research. Their research is conducted mainly from the economic development or industrial transformation perspective. The Institute of Marine Development Strategy of the State Oceanic Administration focuses on the perspectives of legislation, management, and development planning. The University of Tasmania and the University of British Columbia both have the geographical advantages of the sea and contribute high-quality scientific research results in the areas of marine environmental science, marine green development science, and technology.

Fig. 2
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Map of institutions that publish research on sustainable development of the marine economy in China (Data from CNKI)

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Fig. 3
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Map of institutions that publish research on sustainable development of the marine economy in China (Data from WOS)

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Fig. 4
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Map of research institutions on sustainable development of the marine economy in other countries

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2.3 Analysis of authors

Author co-occurrence analysis is used to identify the core authors of a discipline or field and their intensity of cooperation and mutual citation (Figs. 5, 6 and 7). The larger the nodes in the map, the more frequently the authors appeared. Figure 5 shows 389 nodes, 417 connections, and a network density of 0.0055. Figure 6 shows 225 nodes, 269 connections in the research map, and a network density of 0.0107. Figure 7 shows 425 nodes, 568 connections in the research map, and a network density of 0.0063. A combination of the map and the frequency table of authors (Table 5 in Appendix 3) shows that there were already cooperative teams with stable partnerships in Chinese research and other studies shows a certain dispersion.

Fig. 5
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Map of authors of published articles in China on sustainable development of the marine economy (Data from CNKI)

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Fig. 6
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Map of authors of published articles in China on sustainable development of the marine economy (Data from WOS)

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Fig. 7
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Map of authors in other countries publishing studies on sustainable development of the marine economy

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3 Research hotspots

3.1 Keyword co-occurrence visualization network analysis

Keywords are a high generalization of a paper’s theme, reflecting its main point. In the literature analysis, the source of clustering words is set as title, abstract, author keywords, and keywords plus; the clustering thesaurus is selected as burst terms. The node type is the keyword, and the keyword co-occurrence, clustering, timeline, and burst maps are obtained.

Figures 8 and 9 show the co-occurrence map of research keywords. Figure 8 shows 411 nodes, 674 connections, and a network density is 0.008. Figure 9 shows 294 nodes, 1203 connections, and a network density of 0.0297. The keywords with a higher frequency are shown as larger nodes, such as ‘ocean economy’. Other larger nodes include ‘marine industry’ and ‘marine resources’. Combined with the keywords in Table 1, we find that existing Chinese studies emphasize scientific evaluation of sustainable development of the marine economy by constructing a data analysis model and establishing an evaluation index system. For example, based on the perspective of biased technological progress, the PCA-DEA and network DEA models are established to measure the efficiency of sustainable development of the regional marine economy (Erkkilä-Välimäki et al., 2022; Hu & Yu, 2018; Hu et al., 2018); based on an input–output table, some studies conduct a benefit–cost analysis of the sustainable development of marine economy, a regional analysis of marine economic efficiency (Li & Liu, 2017; Zhao et al., 2016; Zheng et al., 2019), and others construct an evaluation index system from the perspectives of resources, environment, science, and technology, talents, policies, and capital, to systematically evaluate the comprehensive growth capacity of the sustainable development of the marine economy, and accordingly propose basic references for local support policies and inter-regional synergistic policies (Ding et al., 2021; Sun & Zhang, 2023; Wang & He, 2020; Wang et al., 2018). In addition, it focuses on realizing sustainable development of the regional marine economy. For example, based on the characteristics of the marine economy of different provinces or regions in China, studies have analyzed the current situation of marine economic development, development potential, and marine environmental quality to provide a reference for creating a marine economic development model for a particular region according to local conditions (Chen & Wen, 2022; Gai et al., 2022; Wang et al., 2022). Finally, the studies also emphasize research on the sustainable development goal planning of the marine industry. For example, from the industrial agglomeration and marine carbon perspectives, the study discusses the development direction of fisheries, marine manufacturing, and other marine industries in the context of sustainable development (Han et al., 2022; Ji et al., 2023; Xu et al., 2020).

Fig. 8
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Keyword co-occurrence map of research on sustainable development of the marine economy in China (Data from CNKI)

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Fig. 9
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Keyword co-occurrence map of research on sustainable development of the marine economy in China (Data from WOS)

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Table 1 Keywords for research on sustainable development of the marine economy (frequency ≥ 8)
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Figure 10 shows 500 nodes and 2409 connections in research keyword co-occurrence map, with the network density of 0.0193. The key nodes are ‘management’, ‘blue economy’ and ‘sustainable development’. Combined with the keywords in Table 2, we find that the hotspots of the existing research on the sustainable development of the marine economy focus on the protection of marine ecology and the path of sustainable development of the marine industry. The three keyword nodes with the highest betweenness centrality are management (0.15), impact (0.15), and fishery (0.15). Tahazzud proposed strategic measures for developing Canadian ports to achieve the goal of balancing economic growth, social development, and environmental protection. The ‘measures’ include sustainability as a key principle in port operations, aiming to achieve the goal of improving environmental quality in the operations of Canadian ports and maintaining competitiveness in the global shipping supply chain (Hossain et al., 2019); Al-Masroori used an improved ecologically sustainable development framework to assess the long-term progress of fisheries in Oman in terms of sustainable development. The study results can be used to guide the evaluation of sustainable development of fisheries in other regions (Al-Masroori & Bose, 2021); Kronfeld-Goharani discussed the implementation of sustainable development strategies by companies investing in marine economy. The study highlights that companies’ efforts, such as the rational use of marine resources, have been effective although not enough to achieve the desired goal of sustainable development of the marine economy. There is still room for improvement in the economic behavior of marine companies (Kronfeld-Goharani, 2018). To better understand the development and distribution of high seas marine resources, Gutiérrez analyzed high seas catches and found an unfair distribution of high seas catches. Therefore, it is essential to develop effective policies to maintain the sustainable development of high seas fisheries (Gutiérrez & Inguanzo, 2019). According to the above analysis, the research focuses more on making scientific evaluations of the sustainable development of the marine economy with indicator systems. Moreover, Chinese researchers focus more on realizing sustainable development of marine economy in a certain region, while others concentrate on certain marine industry.

Fig. 10
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Keyword co-occurrence map of research on sustainable development of marine economy in other countries

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Table 2 Keywords of research on sustainable development of marine economy in other countries (frequency ≥ 15)
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3.2 Keyword clustering mapping analysis

High-frequency keywords are often used to identify hot topics and evolutionary trends in a research field. Figure 11 shows the keyword clustering map of Chinese research. The clustering Modularity Q is 0.6951, which is greater than 0.3; therefore, the clustering effect is significant. The clustering weighted mean silhouette S is 0.9539, which is greater than 0.7; therefore, the clustering result is credible. Different clusters reflect different research hotspots. Software clustering results show that the keywords contained in clusters 0 ‘Marine economy’, 1 ‘Marine Industry’, 2 ‘Marine resources’, and 7 ‘Marine carbon sink’ directly reflect the main research content. The high-frequency keywords contained in Cluster 3 ‘National Economy’ are similar to those in Cluster 0; the keywords contained in Cluster 4 ‘Guangdong Province’ and Cluster 8 ‘Guangdong’ are basically the same, as are the keywords in Cluster 11 ‘Shandong Province’, which are not the research direction but the research scope; Cluster 5 ‘Outlook’, Cluster 9 ‘coordination mechanism’, Cluster 12 ‘Integrated Strategy’, Cluster 13 ‘Direct Influence’, and Cluster 19 ‘Spatial Variation’ do not reflect the main research content. The keywords contained in Cluster 6 ‘Marine Environment’ and Cluster 10 ‘Ocean’ are reflected in Clusters 0, 1, 2, and 7. Therefore, these keywords are discussed in this study.

Fig. 11
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Clustering mapping of keywords for research on sustainable development of the marine economy in China

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Cluster #0 is titled ‘Marine economy’, including keywords such as green development, emerging industry, science and technology innovation, and countermeasures and suggestions. This cluster reflects the research perspectives and contents, and the extent of coordinated development and trend of the marine economy is an important part of building a strong marine country (Zhang & Ren, 2021). Cluster #1 is titled ‘Marine Industry’, and includes keywords such as island economy, research progress, development strategy, and marine management. This shows that marine industry research on the structure and spatial layout focuses on regional differences, spatial agglomeration, spatial and temporal evolution, and the evolution of industrial structure (Li et al., 2022). Optimization, transformation, and upgrading of marine industries should be based on the use of marine resources and its comparative advantages (Zhao et al., 2022). Cluster #2 is titled ‘Marine resources’ and includes keywords such as marine resources, influencing factors, industrial structure, marine strategy, marine science, and technology. This cluster reflects the current situation and protection of marine resources, which is a key objective in the research of sustainable development of the marine economy. Resource and environmental problems arising from the process of marine economic development is increasingly attracting attention. Coordinated development of the marine economy and resource environment should be addressed for the healthy development of the marine economy (Liu et al., 2020). Cluster #7 is titled ‘Marine carbon sink’ and includes keywords such as blue economy, green low carbon, offshore wind power, and energy transition. This cluster shows that ocean carbon sink is a new hotspot in the research of sustainable development of marine economy in China. The ocean is the largest carbon reservoir on the earth. To achieve the strategic goal of ‘peaking carbon dioxide emissions and achieving carbon neutrality’, some key methods include promoting the construction of marine carbon sinks, adjusting the development structure of marine industry (Wang et al., 2021), increasing the scientific and technological research of marine low-carbon technology, vigorously developing the marine renewable energy resource industry, promoting the low-carbon transformation of marine economy, accelerating the construction of an efficient blue carbon system for marine economic development, and improving the level of intensive, economical and sustainable development of marine economy (Tan, 2022; Wang, 2022).

Figure 12 shows the keyword clustering map of research from other countries. The clustering Modularity Q of the research keyword clustering map in other countries is 0.4707, and the weighted mean silhouette S is 0.7631; therefore, the clustering results are significant and the conclusions credible. Clusters 5, 6, 8, and 10 are not directly related to this study. The keywords contained in cluster 2 ‘fisheries management’ and cluster 4 ‘aquaculture’ are repeatedly reflected in clusters 7. We, therefore, do not discuss this issue further.

Fig. 12
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Clustering map of keywords for research on sustainable development of marine economy in other countries

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Cluster #0 is titled ‘ocean governance’ and includes keywords such as blue growth, ocean economy, and sustainable development goals. The studies cover various aspects, such as the definition of a blue economy, building a blue economy to achieve sustainable development goals, the importance of healthy oceans for present and future generations, and saving oceans (Lee et al., 2021). Cluster #1 is titled ‘circular economy’ and includes keywords such as circular economy, plastic pollution, sustainable development, and economic complexity, indicating that circular economy is one of the research focuses (Black et al., 2019). Cluster #3 is titled ‘sdg’ (Sustainable Development Goals), and includes keywords such as marine policy, blue carbon, and ocean governance. Most studies on ocean sustainable development are associated with other disciplines to analyze how other industries can contribute to the sustainable development of marine economy, such as examining the impact of the digital economy, financial policy, and various marine industries on marine low-carbon and carbon trading (Ding et al., 2018, 2021). Cluster #7 is titled ‘fishery’ and includes keywords such as management, governance, and marine resources. Studies have mainly focused on marine fisheries, including development dilemmas, measurement of policy subsidies, fishery ecosystem planning (Cisneros-Montemayor et al., 2022), and comparison and suggestions for fishery development in other regions (Kyvelou et al., 2023). Cluster #9 is titled ‘marine spatial planning’ and includes keywords such as ecosystem services, ecological principles, marine spatial planning, and biodiversity. Studies on marine spatial planning mainly focus on evaluating the applicability of marine spatial planning methods, providing innovations based on practical conclusions, exploring the path of rationally organizing human activities in terms of marine space (Madarcos et al., 2022), and seeking balanced regional development and healthy marine environment.

4 Research and evolutionary trends

The CiteSpace timeline map for keyword clustering uses time as a dimension and connection to establish the inheritance relationship between nodes. By combining the keyword timeline map and the keyword burst map, we can better understand the change process of keywords and the evolution law of hotspots.

In Figs. 13, 14, 15 and 16, keywords appear more frequently during 2000–2010, including marine environment, coordinated development, circular economy, low-carbon economy, regional economy, and path selection. The high-frequency keywords appearing in 2011–2015 are emerging industry, blue economy, evaluation index, marine strategy, index construction, and strong province strategy. The high-frequency keywords appearing after 2016 are relatively fewer than the previous stage. The keyword timeline map shows that sustainable development of the marine economy was extensively studied in China during 2000–2015, and the body of research is constantly evolving.

Fig. 13
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Keyword timeline map of research on sustainable development of the marine economy in China (Data from CNKI)

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Fig. 14
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Keyword burst map of research on sustainable development of marine economy in China (Data from CNKI)

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Fig. 15
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Keyword timeline map of research on sustainable development of the marine economy in China (Data from WOS)

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Fig. 16
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Keyword burst map of research on sustainable development of marine economy in China (Data from WOS)

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In Figs. 15 and 16, keywords, such as environment, sustainability, marine reserve, and marine protected, began to appear more intensively between 2000 and 2010. Then, 2010 onward was the most intensive period of keywords, including protected area, efficiency, blue economy, circular economy, CO2 emission, and green economy. The keyword timeline map shows that research on the sustainable development of the marine economy reached a maturity stage after 2010 in other countries, with new keywords appearing intensively and more keywords from different research perspectives and disciplines.

Over the past three decades, current research topics have constantly evolved over time and process of national development. On the right side of the keyword timeline map are cluster titles of different colors. The timeline axis of the same color as the cluster title represents the evolution of the keywords included in the cluster, and the connection between each keyword represents the existence of evolutionary relationships between different keywords. Figures 13 and 14 show that the marine economy, marine industry, marine resources, national economy, and other clusters of keywords related to the emergence of the time were intensively discussed before 2000. ‘Marine economy’ is closely related to other keywords on the time axis of clustering, indicating the cross-integration of research and knowledge systems of different disciplines. ‘The sustainable development of technological innovation of marine industry’ can be further researched.

Figures 17 and 18 also show similar development characteristics abroad. Take the theme of ‘marine economy’ as an example, the earliest keyword on its timeline is sustainable development; however, studies have found that research development on marine ecosystem, ecology, and other keywords have evolved over the same timeline. The keywords marine ecosystem, ecology, and circular economy have evolved over the same timeline and are closely related to the keywords that appear in different years in the other clustered themes. It can be seen that ‘marine environmental protection’ will continue to be the focus of research in the future.

Fig. 17
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Keyword timeline map of research on sustainable development of the marine economy in other countries

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Fig. 18
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Keyword burst map of research on sustainable development of marine economy in other countries

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5 Conclusion and discussion

This study used a bibliometric method and a literature review method to visualize and analyze research on sustainable development of marine economy over the past thirty years.

An analysis of the number and changing trends of literature on sustainable development of marine economy showed that the research on sustainable development of the marine economy has yielded rich results. Researchers from China already had cooperative teams with stable cooperative relationships, focused on assessing the sustainable development of the marine economy, optimization of marine industry structure, and other areas, with strong policy orientation. Studies on the assessment of marine ecological and environmental benefits analyze the path of sustainable development of the marine industry. The research themes are relatively fragmented and focus more on green development, resource utilization, and the environment. In the past thirty years, sustainable development of the marine economy has gained the much attention. We developed a tentative research framework with systems theory and ecology theory as the theoretical basis, sustainable development of human society as the ultimate goals, and comprehensive sustainable development of politics, economy, society, culture, and ecology as the core content. A multiple evaluation index system for the sustainable development of the marine economy was gradually formed.

Hotspot research on the sustainable development of the marine economy and the visualization and analysis of research frontiers have an important reference value for the issue of development and use of marine resources. Accordingly, an outlook into the future is provided: the factors influencing the sustainable development of marine economy in different regions are not simply linear or non-linear, but a result of the interweaving of several factors. More methods, such as SEM (Structural Equation Modeling) or matter-element model, can be used to accurately identify and determine the impact of various factors on the high-quality development of the marine economy. Existing studies confirm the need for and significance of research on green ocean economic efficiency at the provincial level. Future studies will focus on strengthening of inter-regional linkages, the evolution characteristics, and formation mechanism of marine economic linkage networks from the perspective of flow space. Future studies will also focus on identifying and analyzing the resilience of the subdivided marine economy industry.