Towards Sustainable Development of Fisheries in the Yellow and East China Seas Shared by South Korea and China

Abstract

South Korea and China are located adjacent to Korea’s West and South Seas and China’s Yellow, Bohai, and East China Seas. These seas are semi-closed and are inhabited by many transboundary species. Korea and China signed a Fisheries Agreement in 2000, pledging cooperation for conservation in the Yellow and East China Seas. Discussions for collaborative fisheries management continued; however, competitive fishing has been occurring between them. Moreover, Korean and Chinese fisheries suffer overcapacity, deterioration, and decreased production. Accordingly, they strengthened the fisheries management of their own seas; however, issues continue to exist. Thus, there is an urgent need to develop more effective measures by evaluating and refining the existing system; fisheries management mainly focuses on fishing capacity control. Window-DEA is useful for analyzing the trend of efficiency over time and has been widely used as an evaluation tool for fisheries management measures, particularly fishing capacity. We comprehensively assessed the dynamic fishing capacity of the fishing ground shared by Korea and China per coastal region using Window-DEA for its sustainable development. Our results show the shared fishing ground has suffered from long-term overcapacity, which is expanding further with the intensification of fishing competition between the two countries, implying that the regime currently employed has inherent drawbacks because most naturally inhabiting fish species are transboundary and characterized by active ecological interactions. Our study proposes to set a Korea–China joint fisheries management regime.

1. Introduction

Fisheries management has been shifting from a single-species approach to an ecosystem-based one due to the latter being considered more effective in ensuring the long-term sustainability of living marine resources [1,2]. The ecosystem approach has been applied in various fisheries management systems such as shared resources and designated Large Marine Ecosystems (LMEs). (The concept of transcending national boundaries considering the ecological characteristics of an ecosystem is a global issue, and the concept of “Large Marine Ecosystems (LMEs)” appeared in 1991 by Sherman and colleagues. LMEs are inherently cross-border concepts due to interconnected algae, movement of biological resources, and cross-border pollution in political terms. There are 66 mega-marine ecosystems between the world’s continental borders and the oceans, which are vast oceanic spaces of more than 200,000 km², extending from river basins and estuaries to seaward shelves, including continental shelves, to major ocean current systems.) Therefore, the need for fishery management at the multi-national level has emerged [3,4,5]. South Korea (hereinafter referred to as “Korea”) and China share fishery resources in Korea’s West Sea and South Sea and China’s Yellow, Bohai, and East China Seas. The shared seas are semi-enclosed seas inhabited by many transboundary migratory aquatic species and are thus characterized by an active ecological interaction between the two countries (Figure 1) [6,7,8,9]. In addition, the Yellow Sea is one of the 66 LMEs designated by the Food and Agricultural Organization (FAO), and both Korea and China take part in a cooperative management system through the Yellow Sea Large Marine System (YSLME) program (Korea and China started cooperation in 1991 when they started the “Environment Improvement Project for the Conservation of Biological Resources and Environment in the Yellow Sea” proposed by the World Bank and the Global Environment Fund) that aims to establish a cooperative system between the countries sharing the Yellow Sea by applying the concept of “transboundary” resources and marine environment management [10]. That is, the seas of Korea and China belong to one ecosystem and are closely related to each other [10]. Moreover, the countries already recognize the need for cooperation for the sustainability and environmental conservation of the seas [11].

The United Nations Convention on the Law of the Sea (UNCLOS) was adopted in 1982. It divided maritime space into jurisdictions of a coastal state and clarified the rights and obligations of states within each zone. At the same time, it states that “the problems of ocean space are closely related and must be considered as a whole.” It also mandated cooperation between bordering countries in semi-enclosed and closed seas and recommended that countries cooperate or at least negotiate on cross-border resource management, such as management and conservation of shared resources [12]. Korea and China signed a fisheries agreement in 2000 for overlapping waters after the declaration of the Exclusive Economic Zone (EEZ) and promised cooperation in fisheries [13]. However, it has not yet defined a maritime boundary, and a practical cooperative management system has not been implemented yet [14]. The delimitation of maritime boundaries between the two countries goes beyond the expansion of maritime jurisdiction. Diverse political, social, and economic interests, such as national security, resource utilization, sea routes, and fisheries, are sharply opposed, making it difficult to reach an agreement [15,16,17]. Thus, the two countries are still competing over the sea, causing various problems such as destruction of the marine ecosystem, reduction in fishery resources, maritime accidents, and fishing disputes [16].

The Northwest Pacific fishing ground, common to both countries, is the most intensive fishing area in the world [18]. Korea and China are the most active fishing entities as representative fisheries producers, and their fishing industries have developed rapidly with economic development. Meanwhile, there are signs of apparent ecosystem destruction and resource depletion, such as decreased production and overall biological layer, miniaturization, and early maturity [19,20,21,22]. Korea and China control these effects by implementing various management measures, but the practical effects of these measures have not been significant, and the sustainability of the fishing grounds is still threatened [23,24].

One of the essential elements of sustainable marine ecosystems is to reduce “overcapacity” [25]. Since the FAO adopted the International Plan of Action for the Management of Fishing Capacity in 1999, fishing capacity management has been one of the most critical issues in international fisheries management, based on the “Code of Conduct for Responsible Fisheries” in 1995. In order to reduce overcapacity, the committee recommended that each country measure the fishing capacity of each fishery and set a management plan [26].

Diverse methods ranging from qualitative to quantitative approaches have been proposed to measure fishing capacity. After an extensive review of analysis methods, an FAO expert group proposed the Data Envelopment Analysis (DEA) as the most effective way to measure international fishing capacity [27]. DEA can effectively measure fishing capacity as defined by the FAO, even when data are limited to only information regarding input and output levels in fisheries. For implementing the International Action Plan and the FAO recommendations under the Code of Conduct for Responsible Fisheries, studies on fishing capacity measurement have been actively conducted, with most of them utilizing DEA.

Pascoe et al. (2001) evaluated the fishing capacity of the UK otter trawlers using DEA and observed an overcapacity of approximately 10% on average [28]. Kirkley et al. (2003) also used DEA to measure the fishing capacity of the Malaysian purse seine fishery and emphasized the need for implementing fishing capacity management policies rather than promoting fisheries as overcapacity increases [29]. Castilla-Espino et al. (2014) evaluated the fishing capacity of Georgia, Turkey, and Ukraine fishing vessels participating in anchovy fishing in the Georgia EEZ in the southeastern part of the Black Sea during 2005–2009. Their study showed that overcapacity is continuously occurring and needs to be actively managed. To ensure the sustainability of anchovy stocks, joint fishery management considering ‘transboundary stocks’ was proposed [30].

Window-DEA, a dynamic technique, has been used in many studies to analyze changes and trends in fishing capacity over time. For example, Lindebo (2004) used this technique to analyze the effects of fisheries management systems on the fishing capacity trends of Danish fin-fishing and commercial fishing vessels from 1996 to 2002. The fishing capacity of these vessels was found to be partially increased upon implementation of the fisheries management system [31]. Kim et al. (2007) analyzed the static and dynamic fishing capacity of the Korean large purse seine fishery and found an increase in its overcapacity. This trend is consistent with the profitability trend to some extent [32].

Research using DEA has been actively conducted in Korea and China as well. In Korea, the octopus coastal trap fishery was analyzed for its fishing capacity and a plan was suggested to reduce its fishing effort [32]. Another study used the Window-DEA technique to dynamically evaluate the fishing capacity of each fleet of the large purse seine fishery. Moreover, the effect of fishing capacity changes on the business situation was analyzed [33]. Lee et al. (2008) investigated the fishing capacity of large pair-trawl vessels by size, estimated their appropriate size, and suggested ways to improve fisheries management based on their results [34]. In China, the available data are relatively limited; therefore, the research in each region and sea has mainly focused on each region and sea rather than individual fisheries and species. Rao et al. (2016) evaluated the fishing capacity of the Yellow, South, and East China Seas in 2009–2014 using the DEA and found that the fishery management system was effective [35]. Sun et al. (2016) used DEA to investigate the fishing capacity of 11 coastal areas during 2008–2014, evaluating the effectiveness of implementing the dual control system. They found that more than 30% overcapacity still existed [36]. Zheng et al. (2008) also used DEA to evaluate the fishing capacity of 11 coastal areas during 1994–2005 and identify the problems of the fishing industry. The fishing vessel buyback, dual control, zero growth, and relocation policies introduced in earnest in 1999 showed clear effects. They also recommended utilizing the DEA as a performance measurement tool without quantitative evaluation indicators of the fisheries management system [37].

Korea and China utilize a fishing ground with numerous shared resources because of their geographical, ecological, and water distribution characteristics, and have been actively engaged in fishing activities [6,7,8,9,10]. They have been making individual and cooperative efforts for the sustainable development of marine ecosystems and resources. The total marine capture fisheries landings in the waters of Korea and China have significantly decreased since the 2000s, while fishing effort is continuously increasing. Thus, we expect the seas have been further overexploited, and the overcapacity of the Chinese and Korean fishing fleets has increased remarkably. In this study, we analyzed how effective individual and cooperative fishing capacity management efforts were, by comprehensively considering the fishing activities of both countries in the Yellow and East China Seas shared between Korea and China by applying Window-DEA; we propose a joint fisheries management plan for the future.

2. Korea–China Fishing Ground

2.1. Status

Korea and China have been utilizing the fishing grounds adjacent to the Yellow Sea between them. Fishing conflicts have frequently arisen between the two countries because of the narrow sea between them [38]. These conflicts show different patterns depending on the period. Until the early 1980s, more Korean fishing vessels went out to Chinese waters. However, from the mid-1980s, China’s fishing industry began to develop rapidly, and Chinese vessels entered more and more frequently into Korean waters, a situation which has continued to the present day. As such, the fishing effort of both increased rapidly, and competitive fishing has taken place in the Korea–China fishing ground, leading to problems such as resource depletion. However, the legal norm was not set for a long time between the two countries [13].

With the enforcement of the 1994 UNCLOS, the existing international fishing order based on the principle of “freedom of the seas” has undergone a fundamental change to the sovereignty of a coastal state founded on the EEZ system. Globally, many countries declared EEZs, and Korea (1996) and China (1998) also introduced these zones. This change caused a conflict between Korea and China regarding the delimitation of maritime boundaries and resource management and use [16]. Working-level talks began in December 1993 between the two governments to conclude a fishery agreement on the issue of demarcation of the fishing line between the two countries. From the point of view of the 200 nautical mile EEZ prescribed by the UNCLOS, the distance between the two countries was less than 400 nautical miles, and the maritime boundaries between the Yellow and East China Seas were not agreed upon quickly. Finally, after 19 summits, the Korea–China Fisheries Agreement was signed in 2000. Through a provisional agreement, the two countries have designated the provisional measure zone (the provisional measure zone is an area in which fishing vessels of both countries fish following the laws of the two countries but aquatic resources are jointly managed by the two governments. Article 7, Paragraph 2 of the agreement stipulates that "common conservation measures and quantitative management measures shall be taken in the provisional zone according to the Korea–China Joint Fisheries Committee", including restrictions on the number of vessels and allocation catch quota), the middle zone, and the immediate zone. The purpose of the agreement is to promote the conservation and rational use of marine resources in the Yellow and East China Seas, which are of common interest, maintain fishing order at sea, and strengthen and encourage cooperation in fisheries [13].

Article 13 of the Fisheries Agreement stipulates that the Korea–China Fisheries Joint Committee (hereafter referred to as Committee) should jointly manage resources [39]. The Marine Biological Resources Specialized Subcommittee and the Fishery Guidance Enforcement Working Group have been established and operated. Since the first mutual agreement on the number of vessels and catch quotas in 2001, the 21st Committee has been held annually. The Fishery Guidance Enforcement Working Group has continued to strengthen cooperation on bilateral measures to establish fisheries order, such as joint patrols in the provisional zone and the management of Chinese ships entering the sea on the North Korean side. Additionally, the two countries are also trying to implement common resource conservation measures such as the release of fishery resources. Nevertheless, a practical joint management plan has not yet been established, and most decision-making is still based on the political situation at the time, lacking a scientific basis. However, effective fisheries management is impossible without an accurate understanding of resource status.

Disputes such as illegal fishing and maritime accidents continually occur for shared resources between the two countries. From 2015 to 2019, the Korean Coast Guard seized 1037 Chinese illegal fishing vessels, of which 807 (77.8%) were cases of restriction violations, 171 (16.4%) of illegal fishing in the EEZ, and 59 (5.6%) of territorial water invasions (Unfortunately, only the Korea Coast Guard data was described because there was no statistical data on the Chinese side. In addition, the Korean government did not count the damage by Chinese fishermen, so only Korea’s was presented). In addition, conflicts intensify, with casualties occurring during the crackdown on illegal fishing [40]. These illegalities are of more significant concern because they are usually destructive. In particular, they are utilizing fisheries resources through prohibited fishing methods such as dredging (trawl fishing of Chinese vessels takes the method of sweeping resources by lowering the nets to the bottom of the sea, where the fry of various fish species mainly inhabits. Diggers scrape the bottom of the sea and sweep away fish and shellfish. At this time, all blue crab larvae in the mud are also sucked into the net. The trap mesh of Korean crab fishing vessels is regulated to be over 65 mm, but Chinese vessels have no mesh size restrictions, making it more difficult to manage), stow nets (stow netting is a fishing method in which juvenile fish fishing are overfished by illegally and densely installing fishing gear with a small net size), and trawl nets.

Generally, shared resources subject to competitive fishing are weaker than those not subject to competitive fishing [41,42]. Most of the commercial fish species in the Korea–China fishing ground are “transboundary stocks” that migrate between the EEZs of both countries. Thus, the competition between Korean and Chinese fishermen is becoming more intense. Moreover, with the depletion of aquatic resources in Chinese coastal areas, fishing vessels are moving to farther seas [24]. In particular, the dependence on fishing in the Korean EEZ, which has a relatively high resource abundance, is increasing, and these problems have not been solved. Even though they have established a basis for cooperation in the Korea–China fishing ground, there have been no noticeable outcomes, such as designating a practical joint management system. On the contrary, the situation at the fishing ground is deteriorating.

2.2. Catch

Catch in the coastal regions, located in the Korea–China fishing ground, showed a steep growth until the late 1990s, and after peaking in 1999, a gradual decline (Figure 2). In line with this clear resource depletion trend, both countries implemented various fisheries management systems [24,43]. Nevertheless, the reduction in aquatic resources continues. The decline in the catch of each country indicates that the overall resources in the Korea–China fishing ground are declining. In fact, many studies have reported deterioration of aquatic resources, miniaturization and early maturation of major economic fish species, and a decrease in biosphere diversity [19,20,21,22].

In 1986, China produced approximately 2.5 times more fish (3,884,540 tons) than Korea (1,537,287 tons), and in 2019, China’s catch (10,001,515 tons) was ~13 times that of Korea (766,644 tons), indicating the widening of the fish production gap between the two countries. Korea’s fishing industry developed relatively earlier than China, peaked in 1986, and then showed a downward trend, though there were fluctuations. Compared to the fish production in 1986 (1,537,287 tons), it dropped by ~50.2% (766,644 tons) in 2019. A variety of factors, such as overfishing, reduced fishing ground, increased fishing expenses and decreased fishing population contributed to this decline. In contrast, China showed explosive growth in fish production, increasing by ~3.6 times (3,884,540 tons in 1986 to 14,071,732 tons in 1999 until peak production in 1999; subsequently, it gradually decreased [23,44]. This decline in catch is due to overfishing and the implementation of the Chinese government’s zero-growth policy for fisheries, which controlled production and fishery development [24,43]. In particular, the 13th 5-Year Economic Development Plan in 2016 offshore presented a bold target of reducing fish production by 30% (2020) [45], and in fact, the production of fisheries in China is declining.

2.3. Fishing Efforts

The fishing efforts of Korea and China showed apparent similarities and differences. First, although there is a different period between the two countries, the number of fishing vessels generally rises to a certain point at first and shows a downward trend due to the implementation of the fishing capacity management system (Figure 3a). Since 1994, Korea has restructured fishery through the “Vessel Buyback Program,” as productivity deteriorated because of decreased resources and increased operating expenses (fuel and labor costs). Consequently, the 18,000 offshore fishing vessels decreased from 1994–2002 [46]. The number of fishing vessels reduced in China as well. Under zero growth (1999) and negative growth (2000) for fisheries, a target value (222,000 ships in 2002 to 160,000 ships by 2020) was established in 2003. The number of fishing vessels has gradually fallen to the target value (158,105 vessels in the Korea–China fishing ground) [43].

However, in both countries, the engine power of vessels (kW (kW (kilowatt) is a measure of 1000 watts of electrical power)) increased (Figure 3b). Korean fishing vessels showed a steep rise in engine power of ~5.3 times until the mid-2000s (1,706,631 kW in 1986 to 9,110,002 kW in 2004), declined afterward, and then stabilized. With the rapid increase in fish production in China, the dramatic expansion of the overall fishing industry continued until the late 1990s. Accordingly, the total kW of fishing vessels also increased rapidly (from 4,173,074 kW in 1986 to 11,517,164 kW in 1999, an increase of 286%) [24]. That is, the actual fishing efforts continued to increase despite the government’s restrictions on growth (negative growth and dual control). This is because fishermen expanded their fishing power by increasing engine power according to the fishing vessel control policy which also affected technical development and fishing vessel enlargement. The fishing capacity management system in China was evaluated as insufficient [23,24,44]. After the recently strengthened dual control method of management (2016–2020), total vessel power decreased for the first time in history, suggesting that the strengthened system effectively controlled the fishing capacity of China.

Similarly to the power trend, the fishing effort input per fishing vessel (kW/vessel) in both countries also increased, implying that fishing vessels are getting bigger and fishing power is intensifying (Figure 3c). In contrast to the number and engine power of the fishing vessels described above, Korea’s fishing effort input per fishing vessel was significantly higher than China, being 1.5, 3.03, and 2.54 times that of China in 1986 (38.9 kW/Vessel vs. 25.4 kW/Vessel), 2000 (125.1 kW/Vessel vs. 41.38 kW/Vessel), and 2019 (203.72 kW/Vessel vs. 80.2 kW/Vessel), respectively. The gap widened and then gradually narrowed again.

The fishing labor force trends between the two countries are remarkably different (Figure 3d). Korea’s labor force has steadily declined since 1990, showing a noticeable decrease by the 2000s (a 50% decrease from 51,707 people in 2000 to 27,223 people in 2019). This decrease is attributed to diverse reasons, such as reduced fish production, fishing ground, the number of fishing vessels, increased fishing expenses, and the avoidance of the fishing industry by young people (under 40 years). The rapid decline and aging of the labor force in Korean fisheries are being treated as serious social problems leading to the collapse of the fishing industry [49]. In contrast, the labor force in China reached 1.15 million in 1999, as many rural residents “open access” in response to an increase in production during the fishery growth period in the 1980s and 1990s. Despite policies to restrict fisheries growth, its growth continued into the early 2000s. Thus, in China, the labor force has a relatively large influence on fishing capacity [24]. As the fishermen relocation policy was implemented in 2002, the labor force gradually decreased, and the policy is still being implemented as a major management measure.

3. Materials and Methods

3.1. Research Area

Korea and China are adjacent to Korea’s West and South Seas and China’s Yellow and East China Seas. In addition, their EEZs overlap in these seas. Many studies have comprehensively considered both countries’ production and fishing efforts based on the environmental condition of the single ecosystem between them and the homogeneity of fishing grounds and aquatic resources [50,51], emphasizing that the seas of both countries should be managed cooperatively as one fishing ground based on the ecological concept [8,10]. Accordingly, this study focused on Korea’s West and South Seas and China’s Bohai, Yellow, and East China Seas as the study area, which is referred to as the Korea–China fishing ground because it serves as a fishing ground shared by both countries. Our research aims to examine the dynamic utilization status of the fishing ground by evaluating the regional fishing capacity of the coastal regions of Korea and China adjacent to this fishing ground; thus, the decision-making units (DMUs) are respective coastal regions.

The boundary of each sea differs slightly from study to study [35,52]. In particular, the scope of fishing activities of vessels has been widened because of technological advancement and the reduction in aquatic resources in coastal areas. However, in general, the East Sea of Korea and the South China Sea are not geographic neighbors. Their features are also clearly separated from other seas, and there are significant differences in fish species inhabiting them [47,48]. Therefore, eight regions in Korea, including Gyeonggi-do, Incheon, Chungcheongnam-do, Jeollabuk-do, Jeollanam-do, Jeju, Gyeongsangnam-do, and Busan, and eight regions in China, including Tianjin, Hebei, Liaoning, Shandong, Jiangsu, Shanghai, Zhejiang, and Fujian, were studied (Figure 1).

3.2. Data and Variables

An integrated analysis of the Korea–China fishing ground’s fishing capacity requires unified and extensive data from both countries; in this regard, the only available data is the Fisheries Yearbook of both countries. Although it has the advantage of being the most stable data as public data provided by the government, it is restrained by the fact that it does not offer data by fishery and fish species. Under such a limited range of available data, this study, using the public data on regional fish production (catch) and fishing efforts (number of fishing vessels, engine power of vessels, and labor force) in Korea (the West and South Seas) and China (the Bohai, Yellow, and East China Seas) from 1986 to 2019, we analyzed long-term trends and changes in fishing capacity—data obtained Korean Fisheries Yearbook [48] and China Fishery Statistical Yearbook [47]. Korea’s available data were relatively restricted; with the abolition and inauguration of the Ministry of Oceans and Fisheries, data were transferred. Therefore, we set 1986 as the starting year, using only publicly available data.

The China Fishery Statistical Yearbook classifies “Marine capture fisheries” as a combination of coastal, offshore, and high-seas fisheries. Therefore, it is necessary to subtract the high-seas fisheries from the marine capture fisheries to obtain data from the coastal and offshore fisheries. The number and engine power of high-sea fisheries vessels were obtained from the Yearbook. In contrast, the data on the labor force in high-sea fisheries have not been compiled from 2008 to the present. A previous study estimated the labor force (represented by L) of high-sea fisheries through Ordinary Least Squares (OLS) with kW, and we used this data. As there is, in general, a particular proportional relationship between the two variables as the more kW (denoted by K) of the vessel, the more workers must be employed [36,53]. The regression equation for the labor force in China’s high-sea fisheries was estimated to be $\mathrm{L}=0.0442\mathrm{K}-738.18 \left({\mathrm{R}}^2=0.795\right)$. Based on this, the number of laborers in high-sea fisheries in each region was estimated for the period of 2008–2019, and the coastal and offshore fisheries data were calculated by region.

As the analysis variables, the annual catch of the coastal and offshore fisheries was set as the output, and the labor force (person), fishing effort (kW), and catch per unit effort (catch/vessel) were selected as input variables. Catch Per Unit Effort (CPUE) was set as a proxy variable for the resource quantity. The number of resources is one of the most important variables affecting fishery production and needs to be considered in the production capacity analysis of the fishery sector [29,33]. However, since Korea and China’s resource data are difficult to obtain, a proxy variable was used. The number of fishing vessels is utilized for CPUE calculation, because: (1) fishing vessels are controlled by the fishing license system and vessel buyback in both countries [33]; (2) many previous studies have also used it as an input factor [35,36,37].

3.3. Methods: Fishing Capacity and Overcapacity

Capacity is generally defined in economics as “the level at which a company or industry can produce potential output”, and is a concept widely applied in decision-making and policymaking in various industrial sectors. In previous studies, the concept of fishing capacity is broadly defined as a product definition and an economic definition, just like the general concept of ability discussed above [54,55,56,57]. In a productive context, the fishing capacity refers to the maximum output that an individual fishing vessel or an entire fishery can produce for a certain period when there are no restrictions on fishing activities under the given market, fishery resource, and technical conditions on production maximization [54,57].

In contrast, in an economic context, fishing capacity refers to the level of production that a fishing vessel or an entire fishery can produce for a certain period when there are no restrictions on fishing activities under the given market, fishery resource, and technical conditions based on cost minimization [55,56]. Therefore, in the production context, the input factors determine the maximum potential output under resource, market, and technological conditions. In the economic context, potential production or capacity is determined by the resource, market, technological conditions, fishermen’s decision-making and production activities, and economic utilization of input factors. From an economic point of view, the economic context can be considered to define fishing capacity adequately because it considers economic factors, particularly the production behavior of fishermen concerning revenues and costs so that more specific fishing capacity levels can be assessed.

However, to measure the economic fishing capacity of a country, economic data, such as fishing activity-related costs, must be estimated, and collecting this data is very difficult in reality. In addition, it is more challenging to measure fishing capacity in an economical sense in the case of multi-species fisheries that generally catch a variety of fish species using different inputs [57].

In this respect, an FAO expert group meeting defined fishing capacity as a productive concept and proposed to measure it for each fishery based on it [27]. That is, as defined by Johansen (1968), the maximum potential production level that a fishing vessel or an entire fishery can produce for a specific time when there are no restrictions on fishing activities under the given market, fishery resource, and technical conditions. It measures overcapacity by comparing it with the actual production level [58].

Overcapacity is a phenomenon in which the production level, in the long run, is lower than the target maximum sustainable yield or the fishing cost is higher than the maximum economic yield level—signs such as overfishing investment or overfishing [59]. The overcapacity of fisheries results from the characteristics of fishery resources. Gordon (1954) points out that as fisheries resources are a common commodity that cannot be privatized, there are no exclusive rights to their use, and so, anyone can participate in the fishery. Thus, additional enhancement of fishing capacity is inevitable to preoccupy resources in fishing competition [60]. Moreover, even though fisheries resources have been reduced because of overfishing and reduced production, fishermen try to enhance their fishing capacity further to preserve income. Despite a decrease in fishery resources, the fishing capacity increases [61]. Therefore, if overcapacity is not properly managed, the fishing pressure intensifies, further reducing the resources, and the profitability deteriorates significantly. As a result, sustainable fishery development cannot be expected. In addition, as changes in market conditions cannot automatically resolve overcapacity, fisheries managers must reduce fishing capacity by establishing a management policy.

At the FAO expert group meeting, the peak-to-peak (PTP) analysis, statistical frontier analysis (SFA), and data envelopment analysis (DEA) were suggested as methods to measure fishing capacity. Among these methods, DEA has been most widely used because it can be used even when the available data is limited and can consider multiple output and input factors together [30,62].

3.3.1. Data Envelopment Analysis

Data envelopment analysis (DEA) is an efficiency measure based on linear programming and a non-parametric approach. It estimates the efficiency of a target by comparing the empirical efficiency frontier (relative technical efficiency of production activities, Technical Efficiency) using the data between the input and output factors under several criteria applied in the production possibility set. It was proposed by Charnes et al. (1978), who extended Farrell’s (1957) Technical Efficiency (TE) concept of multiple input-single output to a case where there are multiple inputs and outputs, thereby estimating it for production activities in various fields such as public sector, agriculture, fishery, and resource environment industries [63,64].

The basic principle can be expressed as Equation (1), a model that maximizes the efficiency of DMUs to be evaluated under the constraint—the efficiency of all DMUs is less than or equal to 1 [65].

$$MAX \frac{{\sum }_{m=1}^M{z}_m{u}_{jm}}{{\sum }_{n=1}^N{z}_n{x}_{jn}}$$

(1)

$$s.j. {\displaystyle \sum }_{m=1}^M{z}_m{u}_{j,m}/ {\displaystyle \sum }_{n=1}^n{z}_n{x}_{jn}\le 1$$

$$z_m,z_n\ge 0, j=1, 2, \cdots ,J$$

where, M is the number of outputs for the target DMU, whose efficiency is to be measured; N represents the number of inputs; $u_{jm}$ and $x_{jn}$ represent the observed input and output values of DMU; $z_m$ and $z_n$ represent the weights of each output and input.

The DEA measures fishing capacity based on a linear relationship between the input of fishing effort and production frontier using linear mathematical programming. In other words, it produces the maximum yield for a given amount of input, which is fully consistent with the definition of Johansen (1968) and the productive concept of fishing capacity suggested by FAO (2000).

According to Fare et al. (1989, 1994), to build a DEA for measuring fishing capacity, individual companies (j) were 1, 2, 3, …, J, and the industry uses N inputs to produce M output, the output for j can be expressed as $u_{jm}$ and the input for j as $x_{jn}$ as in Equation (1). However, this must satisfy the conditions of the following Equations (2)–(6):

$$u_{j, m}\ge 0, x_{j, n}\ge 0;$$

(2)

$${\displaystyle \sum }_{j=0}^J{u}_{j,m}>0, m=1, 2, 3, \dots , M;$$

(3)

$${\displaystyle \sum }_{n=0}^N{x}_{j,n}>0, j=1, 2, 3, \dots , J;$$

(4)

$${\displaystyle \sum }_{j=0}^J{x}_{j,n}>0, n=1, 2, 3, \dots , N;$$

(5)

$${\displaystyle \sum }_{m=0}^M{u}_{j,m}>0, j=1, 2, 3, \dots , J;$$

(6)

Equation (2) represents the condition that the input and output must always be positive (+), and Equations (3) and (5) represent the condition that both the sum of the inputs and output must be positive (+). Moreover, Equations (4) and (6) mean that j must input at least one unit of a production factor and produce at least one unit of output. Under these inputs and production assumptions, Fare et al. (1989, 1994) expressed the DEA for estimating production capacity according to the actual input as Equation (7).

$$MAX {\Theta }_{1 }$$

(7)

$$s.t \Theta u_{j,m}\le {\displaystyle \sum }_{j=1}^J{z}_j{u}_{j,m}, m=1, 2, \dots , M;$$

(8)

$${\displaystyle \sum }_{j=0}^J{z}_j{x}_{j,n}, \le X_{j,n}, n=1, 2, \dots ,N$$

(9)

$$z_j\ge 0, j=1, 2, \dots ,J;$$

(10)

where $\Theta$ is a scalar showing how much each DMU can increase output using the input $u_{jm}$ and $x_{jn}$ represent the output (m) and input factor (n) of each DMU (j), respectively, as in Equation (1) above. Furthermore, $z_j$ is the weight of input factors for each DMU. Equation (8) is the constraint on production-by-production type for DMU, and Equation (9) represents the constraint for each input factor by DMU. Equation (10) represents a non-negative condition as a constraint on the weight for each input factor. In DEA, the objective function according to the constraint is analyzed by linear programming to determine the values of $\Theta$ and z that maximize TE.

3.3.2. Window-DEA

Window-DEA is useful for analyzing the trend of efficiency over time by applying the principle of the moving average to multiple periods [66,67]. At first, the window’s width should be determined, which can be defined as a value between 1 and the entire period. If the width is too small, sufficient DMU cannot be obtained, and the analysis result is different from the cross-sectional analysis. Contrarily, if the width is too large, it is not easy to understand the trend over time [68]

There is no specific theoretical method to determine the width, and it can be set according to the researcher’s intention. When the width is p and the analysis period is k, the number of windows ($w$) is $w=k-p+1$ as shown in

Table 1. Window-DEA model.

	Width	1	2	3	⋅	⋅	⋅	⋅	$\mathit{k}$
Window
1		1	⋅	⋅	p
2			2	⋅	⋅	p + 1
3				3	⋅	⋅	p + 2
⋅							⋅
⋅							⋅
w							k + p + 1	⋅	k

. When p is determined, the window efficiency is evaluated sequentially through a moving average. When the number of DMUs is n, pn DMUs are targeted from period 1 to p in the first window, and pn DMUs are targeted from period 2 to $p+1$ in the second window. Evaluations are performed up to the last window, moving backwards by one period.

Window-DEA calculates efficiency metrics over time to analyze the trends and stability in efficiency for each DMU. The row views, averaging through the window of a particular DMU, show trends in how efficiency changes as the window changes. In addition, column views, average by term, of a particular DMU can be compared to the same period efficiency of other DMUs or to assess the time-series stability of efficiency measures.

4. Results

4.1. Fishing Capacity Trends of the Korea–China Fishing Ground

The evaluation of the fishing capacity of the Korea–China fishing ground showed that the fishing ground is in a state of long-term overcapacity despite efforts through various systems to control its overexploitation (Figure 4). In other words, each country’s fishing capacity management was considered ineffective based on the fishing capacity of the fishing ground.

In the first period (~1986–1988 to 1996–1998), the fishing capacity of the Korea–China fishing ground declined (down to 73.1–60.5%) and reached its lowest point (60.5%) in the 1996–1998 period. In other words, its overcapacity increased from 26.9% to 39.5%. Although there were slight fluctuations during this period, Korea and China’s overcapacity expanded (25.8–42% and 22.2–30.6%, respectively). Although Korea’s catch in the fishing ground has decreased continuously since 1986, the fishing efforts—explained by the kW of fishing vessels—have rapidly increased, and the imbalance between the input and output factors has worsened. To raise yield, fishermen expanded their fishing efforts but were unable to improve fish production, which, in turn, increased overcapacity. As China’s catch increased, large access to labor and an increase in the number of fishing vessels expanded the fishing industry, but this growth resulted in overcapacity as the growth of input factors exceeded that of output factors. Their fisheries were in a transition phase during this period and emphasized the need for a fishery management system to overcome the problem of resource overexploitation.

In the second period (~1996–1998 to 2001–2003), the overcapacity of the Korea–China fishing ground decreased again (down to 39.5–32.4%). Even during this period, Korea’s fish production continued to decline, but with the implementation of fishing capacity management measures, the fishing vessel reduction was carried out quickly, and the labor force also declined. These resulted in a slight improvement in overcapacity (down to 42–39.5%) despite a decrease in catch. As China’s fish production started decreasing in 1999, the fishing effort was controlled by following the zero-growth target and by implementing dual control. Thus, the increase in overfishing capacity has subsided to some extent (down to 30.6–28.6%), though with a decrease in production.

In the third period (~2001–2003 to 2003–2005), although China’s production declined after the peak in 1999, the fishing capacity of the Korea–China fishing ground remained stagnant. During this period, Korea’s fishing vessels were adequately reduced in number along with a decrease in fish production, but the overcapacity increased (39.5–45.6%). Because the fishing intensity at domestic fishing grounds increased because of the downsize in the fishing ground after the Korea–China and Korea–Japan fisheries agreements. Moreover, the engine power of the vessels increased significantly. However, although fish production in China has decreased, fishing capacity has enhanced (up to 71.4–75.5%). Because input factors were managed correctly by the effect of policies, such as fisherman relocation, dual control, and zero-growth target. In the fourth period (~2003–2005 to 2016–2018), the entire overcapacity did not change remarkably but increased overall (up to 32.9–37.5%). During this period, both countries had a downward trend in the catch. In particular, while China showed a moderate decline, Korea showed a relatively steep decrease. They implemented various systems to manage the previously expanded fishing effort, but the actual fishing intensity was not controlled enough, thus causing increased overcapacity.

In the fifth period (~2016–2018 to 2017–2019), the overfishing capacity in the fishing ground slightly decreased (down to 37.5–35.2%). Recently, concerns about fisheries resource depletion have become a reality in both countries. They have recognized the failure of existing management policies and have implemented a strengthened system. Korea implemented a plan to improve the structure of coastal and offshore fisheries to implement the existing fishing capacity management system systematically. In addition, the management system was changed from input to output control—based on the total allowable catch (TAC) system [69]. China has proposed a target for reducing production and fishing effort under the 13th 5-Year Economic Development Plan and has subsequently met this target. The resulting improvement is referred to as a positive signal for sustainable development in the Korea–China fishing ground.

Regardless of the 16 regions studied, two regions in China (Tianjin and Liaoning) showed an increase in overcapacity by 5% and 3%, respectively (

Table 2. Results of window-DEA, by region. [Tianjin (TJ), Hebei (HB), Liaoning (LN), Shanghai (SH), Jiangsu (JS), Zhejiang (ZJ), Fujian (FJ), Shandong (SD), Busan (BS), Incheon (IC), Gyeonggi-do (GG), Chungcheongnam-do (CN), Jeollabuk-do (JB), Jeollanam-do (JN), Gyeongsangnam-do (GN), Jeju Island (JJ)].

Window	BS	IC	GG	CN	JB	JN	GN	JJ	TJ	HB	LN	SH	JS	ZJ	FJ	SD	Average
1986–1988	0.964	0.510	0.693	0.415	0.499	0.997	0.758	0.644	0.000	0.553	0.445	0.589	0.706	0.969	0.960	0.962	0.667
1987–1989	0.982	0.487	0.783	0.378	0.481	0.968	0.726	0.685	0.000	0.566	0.527	0.598	0.655	0.997	0.983	0.998	0.676
1988–1990	0.986	0.446	0.668	0.377	0.447	0.928	0.822	0.553	0.000	0.564	0.600	0.581	0.614	0.967	0.977	0.962	0.656
1989–1991	0.970	0.420	0.674	0.455	0.429	0.998	0.916	0.467	0.000	0.562	0.656	0.595	0.641	0.963	0.966	0.981	0.668
1990–1992	0.954	0.445	0.613	0.458	0.437	0.935	0.907	0.424	0.000	0.549	0.668	0.581	0.587	0.937	0.982	0.949	0.652
1991–1993	0.938	0.438	0.701	0.454	0.441	0.916	0.936	0.443	0.000	0.590	0.744	0.600	0.552	0.842	0.984	0.919	0.656
1992–1994	0.980	0.373	0.573	0.425	0.456	0.974	0.959	0.381	0.000	0.567	0.730	0.583	0.572	0.891	0.986	0.973	0.652
1993–1995	0.993	0.345	0.470	0.409	0.499	0.974	0.974	0.378	0.000	0.543	0.743	0.575	0.612	0.924	0.982	1.000	0.651
1994–1996	0.993	0.320	0.361	0.402	0.487	1.000	1.000	0.386	0.000	0.538	0.664	0.559	0.617	0.982	0.974	0.995	0.642
1995–1997	0.991	0.324	0.367	0.397	0.432	1.000	0.999	0.395	0.000	0.522	0.659	0.553	0.468	0.901	0.988	0.958	0.622
1996–1998	0.937	0.329	0.380	0.491	0.409	0.977	0.994	0.396	0.116	0.531	0.652	0.565	0.465	0.884	0.993	0.974	0.631
1997–1999	0.983	0.363	0.507	0.552	0.480	0.948	0.988	0.412	0.345	0.544	0.727	0.623	0.455	0.928	0.992	0.998	0.678
1998–2000	0.960	0.416	0.492	0.618	0.503	0.981	0.991	0.523	0.573	0.550	0.786	0.672	0.439	0.971	0.992	0.991	0.716
1999–2001	0.963	0.411	0.422	0.535	0.473	0.997	0.987	0.556	0.613	0.489	0.766	0.656	0.431	0.995	0.995	0.977	0.704
2000–2002	0.958	0.455	0.431	0.524	0.483	0.990	0.979	0.656	0.794	0.448	0.863	0.689	0.454	0.993	0.992	0.947	0.728
2001–2003	0.945	0.426	0.326	0.517	0.507	0.979	0.965	0.661	0.806	0.375	0.829	0.667	0.512	0.989	0.938	0.994	0.715
2002–2004	0.991	0.433	0.288	0.608	0.623	0.987	0.981	0.660	0.893	0.451	0.941	0.714	0.489	0.987	0.915	1.000	0.748
2003–2005	0.991	0.362	0.162	0.615	0.500	0.981	0.963	0.637	0.559	0.430	0.839	0.640	0.506	0.995	0.996	0.999	0.698
2004–2006	1.000	0.390	0.166	0.641	0.451	0.983	0.969	0.617	0.494	0.490	0.834	0.639	0.509	0.991	0.988	0.995	0.697
2005–2007	0.987	0.451	0.167	0.666	0.429	1.000	0.973	0.585	0.457	0.507	0.773	0.636	0.524	0.970	0.973	0.994	0.693
2006–2008	0.986	0.432	0.171	0.558	0.376	1.000	0.988	0.538	0.333	0.525	0.799	0.609	0.532	0.947	0.983	0.983	0.672
2007–2009	1.000	0.439	0.156	0.559	0.368	0.975	0.994	0.508	0.272	0.532	0.804	0.601	0.556	0.989	1.000	0.994	0.672
2008–2010	0.965	0.422	0.166	0.598	0.361	0.960	0.995	0.483	0.266	0.516	0.793	0.593	0.589	0.988	0.995	0.986	0.667
2009–2011	0.965	0.433	0.178	0.661	0.384	0.999	0.997	0.453	0.278	0.501	0.778	0.602	0.580	0.998	0.993	0.986	0.674
2010–2012	0.986	0.443	0.216	0.677	0.394	0.982	0.990	0.467	0.274	0.463	0.795	0.608	0.567	1.000	0.987	1.000	0.678
2011–2013	0.998	0.434	0.219	0.639	0.374	0.932	0.987	0.473	0.286	0.466	0.792	0.600	0.544	0.998	0.990	1.000	0.671
2012–2014	1.000	0.423	0.215	0.659	0.362	0.945	0.995	0.469	0.339	0.479	0.824	0.610	0.544	1.000	0.996	1.000	0.679
2013–2015	1.000	0.401	0.220	0.686	0.368	0.980	0.999	0.458	0.303	0.518	0.796	0.612	0.544	0.996	1.000	1.000	0.680
2014–2016	0.980	0.394	0.245	0.698	0.409	0.981	0.981	0.463	0.259	0.544	0.759	0.610	0.536	1.000	1.000	1.000	0.679
2015–2017	0.979	0.367	0.268	0.748	0.426	0.967	0.976	0.508	0.249	0.529	0.740	0.614	0.522	0.992	0.966	0.950	0.675
2016–2018	0.982	0.352	0.276	0.781	0.448	1.000	0.979	0.533	0.254	0.573	0.745	0.629	0.510	0.978	0.913	0.918	0.680
2017–2019	0.987	0.357	0.284	0.861	0.468	0.998	0.976	0.561	0.260	0.562	0.724	0.640	0.548	0.991	0.943	1.000	0.697
Average	0.978	0.408	0.370	0.564	0.444	0.976	0.958	0.512	0.282	0.518	0.744	0.614	0.543	0.967	0.979	0.981	0.677

), because of the slight increase in their fishing efforts despite the decrease in production. Thus, we believe that it is necessary to recognize that an increase in fishing effort will inevitably lead to an increase in overfishing capacity under the resource condition that has deteriorated. Furthermore, we propose further strengthening the institutional effect by preparing improvement measures for areas where the overfishing capacity has increased.

4.2. Fishing Capacity Trends of the Korea–China Fishing Ground in Korea and China

Comparing the fishing capacities of Korea and China, the overcapacity of Korea was generally higher than that of China (Figure 4). On average, over the entire period, there was an overcapacity of 40.5% in Korea’s region and 28.9% in China because the average fishing effort (kW/vessel) in Korea was more severe than that in China. Although China showed a much higher level of absolute fishing effort (kW, number of fishing vessels) than Korea, the development of the Korean fishing industry was relatively faster than the Chinese fishing industry, and the technical development and enlargement of vessels advanced earlier in Korea than in China. Moreover, the CPUE (Catch/Vessel) of Korea in 2019 (21 tons) was found to be only 27.6% of that of China (76 tons). This value shows that China has a higher fishing vessel level than Korea in catch.

We analyzed the fishing capacity trends of both countries closely and found an inverse relationship between the two. Moreover, the correlation of the results from 2000–2002 to 2017–2019 showed a significant negative relationship (−0.64416). The correlation analysis of the fishing capacity 2000–2002~2017–2019 periods in Korea and China was −0.64416, and the p-value was 0.002. In this regard, we believe that the condition of the Korea–China fishing ground has further deteriorated since the signing of the Korea–China Fisheries Agreement in 2000. That is, through the agreement, Korea and China promised to rationally use and preserve the fishing ground and resources, but the goal was not achieved under the competition between them. Both countries evaluated that their fishing grounds were reduced, and interests were infringed because of the agreement [70,71,72]. The establishment of EEZ granted exclusive rights to systematic ecosystem development and conservation. However, under the conditions of the Korea–China fishing ground, this can act as an element of conflict and an obstacle to rational resource management; hence, multi-national level management is required.

5. Discussion

The purpose of fisheries management is to ensure the sustainability of marine ecosystems and fisheries resources [25]. As major fishing countries, Korea and China have fulfilled their obligations and responsibilities for fisheries sustainability through individual and cooperative efforts for decades. However, our results show that the Korea–China fishing ground is in a state of long-term overcapacity, which is gradually worsening, threatening the sustainability of the shared fishing ground. Such trends were also observed in the respective fisheries of Korea and China. In addition, the overcapacity of each country demonstrates an inverse relationship after the 2000s—when one increased, the other decreased. During this period, the production of both countries dropped, and their overcapacity increased, indicating that the fisheries competition between the two countries can adversely affect resource conservation. These results imply that the fishing activities of Korea and China are closely influenced by each other and that joint fisheries management is crucial for the sustainable use of the fishing ground.

Fisheries management in Korea and China has been implemented for decades and has been strengthened due to the deterioration of the production environment and the sustainable development goals. However, the production of the Yellow and East China Seas shows an overall decline, while the overcapacity is increasing, gradually worsening with time. That is, it is no longer possible to increase production by expanding the amount of fishing effort, such as the number of fishing vessels and by improving technology, which only increases the overcapacity of the fishing ground. Moreover, idle fishing capacity resulting from overcapacity caused excessive fishing activities, worsening fishery management, and competitive fishing. In particular, competitive fishing went beyond the border, and fishing activities expanded from within each country to overseas, which caused fishing disputes [38,73]. In this regard, overcapacity is the fundamental problem of the Korean and Chinese fisheries, and effective control of fishing efforts is required. In the YSLME Project of UNDP and GEF, the priority for the Yellow Sea was also the input control [10,74].

Recently, due to serious overexploitation, Korea and China enhanced fishing capacity controls, which have shown to be adequate. The fishing capacity management should be continuously supplemented through annual/quarterly evaluation and managed in more detail through the region, fishery, and species assessment. In particular, each fishery and fish species’ fishing capacity management is comprehensively implemented with output control—TAC, ITQ—which could make the overall management measures conducted systematically.

Korea and China are using limited aquatic resources together in one marine ecosystem [8,10,50]. Previous studies have clearly indicated that in the case of the fish resources that are distributed across the EEZs of several countries or when there is competition for shared resources if the coastal countries do not cooperate to manage resources, its condition accessible to weaker than other resources [41,42,75]. Through this study, we find out the same phenomenon is occurring in the Korea–China fishing ground. Korean and Chinese vessels compete for common resources because most of the major commercial fish species migrate between the EEZs of both countries. Under such a complicated environment, shared resources are being threatened. International norms strongly recommend the duties and responsibilities of joint management of common aquatic resources [76]. Korea and China signed the Korea–China Fisheries Agreement in 2000, pledging cooperation for the conservation of the Yellow and East China Seas, discussions for cooperation in fisheries management continued, but a system was not yet set.

Korean and Chinese fisheries management are switching priorities to output control [43,69]. In this process, various limitations were encountered, due to the failure to establish an appropriate cooperative system. For example, both countries conducted resource assessments in their EEZs in response to the decrease in their domestic fisheries resources, aiming to fully implement the resource management system, including setting up TAC. However, owing to the migratory stocks, results will highly likely be misinterpreted. Moreover, although many studies have been conducted on limited conditions and in the short-term, as evidence for such resource management measures requires sufficient long-term ecological and scientific data, it is difficult to carry this out. In addition, domestic fisheries control is constrained because of competitive fishing between Korean and Chinese vessels. Korea introduced the TAC system in 1999 and is making efforts to fully execute it. However, regarding fishing in the Yellow and East China Seas, Korea could not impose restrictions only on domestic vessels, making the enforcement incomplete. Under the environmental conditions of the Korea–China fishing ground, sustainability cannot be guaranteed without cooperation.

The bilateral agreement regime currently employed by Korea and China has inherent drawbacks. However, these are not just limited to Korea and China. The transition from “free of the sea” to the “coastal state system” aimed at systematically developing and conserving fishery resources by granting exclusive rights by establishing EEZs has caused many countries to face the problems of maritime boundary delimitation and shared resource management. Since fisheries resources do not move following jurisdictional boundaries, conflicts between bordering countries over shared and migratory resources have arisen. Indeed, some countries are successfully established joint fisheries management under similar circumstances. These examples may be of considerable significance to Korea and China and should be utilized. Therefore, the Korea–China fishing ground should also be managed by a collaborative approach to eliminating the race-to-fish and the resulting depletion of fish stocks, and it must advance to the Korea–China joint fisheries management system.

The Norwegian–Russian (in the Barents Sea) and Canada–USA (in the Gulf of Maine) joint fisheries management systems are regarded as the most successful cases [76,77]. Norway and Russia signed the 1975 Agreement on Cooperation in the Fishing Industry, which targeted cod (Gadus morhua) and haddock (Melanogrammus aeglefinus)—species with high commercial value migrating around the Barents Sea. Because these species have a high risk of depletion if overfished by one country not implementing appropriate conservation measures, they are easily exposed to the race-to-fish. The Joint Russian–Norwegian Fisheries Commission was established as a consultative body for joint fisheries management. Scientific tasks, such as stock assessment, are carried out by the International Council for the Exploitation of the Sea (ICES) separately from the joint committee to ensure transparency and propose recommendations to the committee. The joint committee organizes delegations, including the Ministry of Foreign Affairs and Trade, the Ministry of Oceans and Fisheries, marine scientists, and fishermen from each country for bilateral consultation, and holds annual meetings. This practical resource management is based on trust and research cooperation [78,79]. This case provides many implications as a cooperative initiative has successfully developed though an ideological gap. Surprisingly in 2010, Russia and Norway succeeded in establishing a maritime boundary, and their cooperation has been shown to have distinct outcomes reducing conflicts and conserving the condition of resources [80,81].

In the Gulf of Maine, enforcement of the Canada–USA fisheries agreement in 1990, set up a series of collaborative management initiatives to deal with transboundary resources [77]. The subject of maritime boundaries delimitation was resolved as the International Court of Justice (ICJ) established the international boundary in the Gulf of Maine in 1984 [77,82], but the issue remained regarding managing transboundary resources. The Canada–USA Transboundary Resources Steering Committee was established in 1995 and meets every 2 years and serves as an overall consultative forum for coordinating transboundary fisheries management. In 1998, the Steering Committee established the Transboundary Resource Assessment Committee (TRAC) to provide scientific advice on cod, haddock, and yellowtail flounder stocks and recommend appropriate catch levels. Founded in 2000 and made up of government-industry representatives from both countries, the Transboundary Management Guidance Committee (TMGC) is the primary group for addressing resource management strategies [77,82]. Canada–USA successfully created cooperating system managing transboundary marine living resources, moving forward collaboratively approaching the conservation of ecosystems—how to respond to climate change.

For sustainable development of the Korea–China fishing ground, a Korea–China joint fisheries management system must be created. Specifically, the Korea–China Joint Fisheries Management Steering Committee, Management Guidance Committee, and Resource Assessment Committee will organize by referring to the Canada–USA model. Since the two countries’ mutual interests are sharply opposed, each committee and the working group should execute tasks independently to help ensure freedom from national interests.

Regular meetings are held twice a year for three years until the establishment of the system, and after the implementation of the integrated TAC pilot program (scheduled in 2026) once a year. Korea and China each appoint one representative of the Steering Committee and consist delegation of the Steering Committee. The committee (1) comprehensively reviews all issues related to the implementation of cooperation; (2) takes charge of overall decision-making related to the implementation based on the implementation and investigation results of the working group of the resource investigation committee and management guidance committee; (3) holds a regular meeting for consultations and makes proposals and recommendations for the parties. The delegation to the Steering Committee consists of 18 people: a designated representative (one each), a representative of the Management Guidance Committee (one each), a representative of each division of the Management Guidance Committee (three each), a representative of the Resource Investigation Committee (one each), and a representative of the Fisheries Authority (one each) and representatives of fishermen from each country (one each).

The Korea–China joint fisheries management system aims at the conservation and sustainable development of the Korea–China fishing ground based on scientific cooperation. The short-term goal is to introduce a collaborative resource management plan, an integrated TAC, for highly commercially valuable fish species and to establish joint management initiatives. In the long term, led by Korea and China, a maritime order in Northeast Asia by encouraging other neighboring countries’ participation, namely North Korea and Japan, will be founded and should fulfill responsibilities for sustainable development.

First, conduct close scientific cooperation. A successful joint management system cored scientific cooperation [76,78,79]. Unfortunately, that is the vulnerability of the current system. At first, countries unify the standard for ecological and scientific resource assessment conducted individually and proactively share the results. The Resource Assessment Committee should guide a resource survey on major commercial fish species in the Korea–China fishing ground, and advice from North Pacific Marine Science Organization (PICES), ICES, and leading countries is used. Accurate ecological evidence helps ensure the success, confidence, and transparency of cooperative management initiatives. Moreover, it also eradicates political decision-making and enables more scientific and rational decision-making.

Second, unify resource management standards for major common fish species. Applicable regulations include closed seasons, mesh size restrictions, prohibited fishing gear, and minimum size requirements. This step reduces contradictions and disputes in resource management resulting from different standards between countries and fundamentally prohibits acts of ecosystem destruction in illegal fishing.

Third, enhance the efforts of sanctions and support between the two governments to prevent illegal fishing. If illicit fishing is discovered, fishermen should be warned by taking strong measures—bans on licenses and exclusion from subsidies. In addition, by adjusting and expanding subsidies—fishermen relocation and closed season subsidies—such social support should provide to discourage fishermen from inevitably engaging in illegal fishing.

Fourth, intensify guidance and education for fishermen. Korea and China have combated illegal fishing by strengthening supervision and regulation. Although strong sanctions generally act as incentives for compliance, they do not fundamentally solve the problem [83]. It is no exaggeration to say that the target of fisheries management measures is fishermen, and their participation determines the success or failure of the system. In this respect, to improve the awareness of fishermen, the Management Guidance Committee should produce educational programs for fishermen to enhance their understanding of Korea–China fishing cooperation, management system, regulation, and resource conservation, and provide regular training. Moreover, fishermen should be positively involved in the decision-making process as stakeholders, as in the case of the Barents Sea [84]. Currently, the Korea–China Fisheries Joint Committee and YSLME consist only of government and working-level officials, and fishermen sometimes do not assent to its determination [70,71]; partaking makes them voluntarily conserve common resources with responsibility.

The maritime boundary delimitation between Korea and China is not simply an extension of maritime jurisdiction, but various interests—EEZ delimitation, territorial disputes, national security, maritime land routes, and resource utilization—are in intense conflict [15,16,17]. It will take considerable time to establish a joint management system. Fortunately, the current system has a foundation for decision-making and cooperation (Korea–China Fisheries Agreement, Korea–China Joint Fisheries Management Committee) [8] and an institution (TACs). The committee is the communication channel between Korea and China and should be utilized as the main body of Korea–China joint fisheries management. Furthermore, Resource management requires numerous ecological and scientific data, institutional basis, and experience. To implement TACs entirely, Korea and China already conduct ecological and scientific work. Under such experiences, a joint management system could be easily achieved if both countries actively cooperate.

6. Conclusions and Future Work

Much controversy surrounds the Korea–China fishing ground. Its aquatic resources are significantly reduced, which is not an individual trend in each country; it is an overall trend of the shared fishing ground. Nevertheless, to catch a little more, both countries have been fighting an exhausting battle. The irony is that they are seriously aware of the resource depletion in their own seas and are constantly making efforts to manage it. However, the other party still regards it as an object of pursuit of profit and does not stop competition. Under the current competitive relationship, the fishing ground is inevitably the target of profit-seeking, and it is no longer possible to design a rational and effective management plan. Both countries must cooperate and act for the sustainable development of the Korea–China fishing ground.

The existing Korea–China fisheries management regime lacks scientific cooperation and limits the available data. Our study utilized the data on production, the number of vessels, kW, and labor force per coastal region and did not take into account data on various production factors and resources; thus, the results cannot explain the status of all individual fish species and fisheries. Moreover, many factors cause resource depletion; thus, our proposal alone cannot solve all the problems. Therefore, through implementing the Korea–China fisheries joint management, data sharing and joint research should conduct, and complementary analysis by considering the fish resources and various production data.

The Korea–China fishing ground is also adjacent to other countries—North Korea and Japan—for the sustainable development of our fishing ground should unite with them. However, such cooperation is challenging given the complex interests of Northeast Asian countries, especially in maritime issues. Insufficient cooperation in fisheries restricts related research and data, our study also could not utilize data from other countries. In this respect, as major fishing producers, Korea and China should establish a joint fisheries management system and lead other countries to encourage participation; through this, we will work together to set the maritime order in Northeast Asia and ensure the sustainable development of our fishing ground.