Study on Improving International Cooperation Frameworks for Combating Illegal, Unreported, and Unregulated Fishing to Achieve Sustainable Use of Fishery Resources

Abstract

Despite global initiatives to combat Illegal, Unreported, and Unregulated (IUU) fishing, such activities continue unabated. As a response, states are encouraged to join the Food and Agriculture Organization of the United Nations Port State Measures Agreement (PSMA) as a countermeasure. Despite these efforts, it is suspected that many IUU fishing activities involve non-party or unknown vessels that evade international sanctions. This study aims to propose technical and institutional improvement measures in light of these challenges. First, using available IUU vessel lists, we conducted independent-sample comparisons and paired-sample comparisons to analyze the characteristics of IUU vessels. As key solutions, we propose the formation of a global collaborative body to facilitate an integrated information chain, the implementation of advanced technologies for systematic operations, strategies to encourage PSMA accession by non-parties, market investigations, and enhanced national inspection and organizational capabilities. Furthermore, this study seeks to strengthen global deterrence of IUU fishing activities by proposing a phased international cooperation framework to enhance the feasibility of integrating the PSMA, Global Record (GR), Global Information Exchange System (GIES), and Regional Fisheries Management Organization (RFMO) systems. These strategies are expected to contribute positively to the transparent governance, sustainable management of fishery resources, and safety officers and vessels.

1. Introduction

With the increasing awareness of the social and environmental consequences associated with IUU fishing, the international community has undertaken multifaceted initiatives to eradicate excessive and unregulated exploitation as well as conserve fishery resources for sustainable marine ecosystems [1]. According to one study, the economic damage caused by IUU fishing is estimated to range from USD 26 billion to 50 billion annually [2]. Some scientists suggest that if current rates of depletion persist, most large predatory fish stocks will have collapsed by 2048 [3]. To combat IUU fishing, the international community incorporated regulatory frameworks into various instruments, including the 1982 United Nations Convention on the Law of the Sea (UNCLOS), 1993 FAO Compliance Agreement, and 1995 United Nations Fish Stock Agreement (UNFSA) [4]. In addition, an international legal and policy framework to combat IUU fishing has been established through the United Nations Convention on the Law of the Sea (UNCLOS) and the FAO Port State Measures Agreement (PSMA), both of which aim to ensure sustainable fisheries governance [5]. A prominent initiative in this domain is the Port State Measures Agreement (PSMA), which is led by the Food and Agriculture Organization (FAO). The PSMA is the first binding international agreement specifically targeting IUU fishing. It establishes a minimum set of standard measures for parties to apply when foreign vessels request entry into their ports or are present in their ports [6]. Numerous Regional Fisheries Management Organizations (RFMOs) have also incorporated Port State Measures (PSM) as components of their Conservation and Management Measures (CMMs) [7]. Additionally, to support the effective implementation of the PSMA, the FAO established the Global Record (GR) to identify vessels and operates the Global Information Exchange System (GIES), which facilitates the sharing of port inspection results among parties [8,9]. Although the GR and GIES have only been officially operational since 2017 and 2023 [8,9], respectively, there is still a lack of data, significant information gaps among countries, and insufficient linkage with RFMO information systems. In addition, the intention to engage in IUU fishing is presumed to be determined by several factors. First, the potential offender will consider the degree of effort involved in getting the illegally caught species to the intended markets [10]. Second, the offender will calculate the possible reward by considering the availability of the resource sought (i.e., commercially significant species), regardless of the effort [11]. Third, the offender will calculate the possible risk of being caught [12]. This risk calculation will entail not only the risk of being caught while fishing illegally at sea but also the risk of being detected while offloading the fish at a port [13]. Nevertheless, despite international efforts to eliminate IUU fishing through the PSMA, high-risk vessels that have not acceded to the PSMA are still more likely to call at “safe haven” ports, which contributes to the persistence of IUU fishing activities [14]. To address these risks, port states must possess both the surveillance systems and the willingness to detect IUU fishing activities at their ports. Likewise, flag states must thoroughly monitor their own vessels, take appropriate sanctions when IUU fishing is detected, and demonstrate the will to enforce compliance. To achieve this, more countries need to accede to the PSMA, collect and promptly share information, and strengthen the cooperation framework among member states. Accordingly, this study aims to analyze the relationship between the flag states of IUU vessels and their PSMA membership status and to propose a technical and policy-oriented international cooperation model to enhance information integration and strengthen global collaboration.

1.1. Research Objectives

As shown in

Table 1. Previous studies on PSMA implementation capacity and RFMO cooperation.

Title	Key Findings
IUU Safe Havens or PSMA Ports: A Global Assessment of Port State Measures [14]	Evaluated global IUU fishing risk levels of ports using AIS data, and highlighted characteristics such as port ranking. Emphasized the need for port state cooperation, as PSMA non-party ports may serve as safe havens for IUU catch.
The Collective Effort of the United Nations Specialized Agencies to Combat IUU Fishing [15]	Analyzed the Joint Working Group (JWG) cooperation framework among UN agencies such as FAO, IMO, and ILO to combat IUU fishing. Highlighted the importance of port inspections and interagency collaboration at both the national and regional levels.
Don’t Follow Trends, Start Trends: PSMA Implementation and Port State Measures [16]	Assessed port rankings based on vessel traffic and IUU fishing risk. Provided recommendations for enhancing PSMA implementation capacity, including international cooperation and technical assistance.
International Cooperation as a Key Tool to Prevent IUU Fishing and Disputes over It [17]	Stressed the importance of international cooperation, including the sharing of experiences and information among countries, due to existing disparities in IUU fishing enforcement capabilities.
Coordination between RFMOs on mutual recognition of IUU vessel lists [18]	Identified the lack of a centralized body for compiling IUU vessel lists across RFMOs as a problem. Proposed policy solutions to promote mutual recognition and the exchange of these lists.
A study on the IUU Fishing Management System in the United States [19]	From 2014 to 2015, 25 Ecuadorian fishing vessels were found to have violated sea turtle conservation measures and dumped tuna and trash at waters of the Inter-American Tropical Tuna Commission (IATTC), and some vessels were found to have engaged in repeated IUU fishing, leading to the U.S. designating them as IUU fishing countries. The Ecuadorian government imposed sanctions on the fishing vessel in question, resulting in its removal from the list of IUU fishing countries, and in 2016, it joined as a party to the PSMA.

, previous studies have highlighted the importance of cooperation not only among port states through PSMA accession but also among international organizations such as FAO, IMO (International Maritime Organization), and ILO (International Labor Organization). Furthermore, they emphasized the critical role of information exchange in overcoming disparities in implementation capacity among countries striving to eliminate IUU fishing. And, at the time when it was a PSMA non-party, it was designated by the USA as an IUU fishing country and, after being delisted as an IUU fishing country, appropriate measures were taken for the relevant vessel, and in the process, it joined as a PSMA party. In this case, it can be seen that the PSMA party has made significant efforts to be delisted from IUU fishing and to combat IUU fishing. However, they have not addressed specific models or operational frameworks. In this study, empirical data on IUU fishing were analyzed and verified, revealing that PSMA non-party vessels and vessels of unknown nationality constitute most IUU fishing operators. This underscores a critical vulnerability in the current regulatory system. Based on this insight, we aimed to develop comprehensive technical and institutional strategies to enhance global capabilities in combating IUU fishing. Additionally, we attempted to develop and present a model framework for integrating multiple information systems and datasets related to IUU fishing activities. Therefore, this study, while building on the implications of previous research, presents concrete policy measures that are both empirically analyzed and practically feasible. Given this fact, its academic and policy contributions are expected to be significant.

1.2. Research Methods

First, this study analyzed IUU vessel lists published by RFMOs and Trygg Mat Tracking (TMT) to identify current trends, patterns, and types of IUU fishing. Second, independent-sample comparisons (using independent-sample t tests) and paired-sample comparisons (using paired-sample t tests) were conducted using the TMT IUU list to verify whether PSMA non-party vessels have a higher likelihood of being delisted from the IUU vessel list and a higher likelihood of engaging in IUU fishing activities. The analysis was performed using SPSS (Version 25.0, IBM Corp., Armonk, NY, USA), applying a significance level of 0.05, and both independent-sample t tests and paired-sample t tests were conducted. The IUU vessel list contained many “dark vessels,” such as unknown vessels deliberately engaging in IUU fishing, which limited the use of data suitable for conducting independent-sample and paired-sample t tests. Third, the objectives and operational mechanisms of the Global Record (GR) and Global Information Exchange System (GIES)—established under the PSMA of FAO—were examined. Fourth, we compared the information obtained from the analysis of IUU vessel lists with the structures of the GR and GIES to identify areas for improvement. Fifth, we proposed enhanced measures to address IUU fishing to promote transparent fisheries management.

2. Status and Specification Analysis of IUU Vessels

The global list of IUU vessels is accessible through the websites of RFMOs, the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR), as well as through TMT. CCAMLR’s primary objective is the conservation of Antarctic marine life, whereas the main focus of traditional RFMOs is fisheries resource management.

A key difference between the two datasets is that IUU vessel lists registered with RFMOs frequently include cross-listed vessels, that is, vessels listed across multiple RFMOs. Contrastingly, the RFMO IUU lists provide information on the current and previous flags of the vessels at the time of listing. TMT data, simultaneously, include delisting histories, which provide additional information on changes over time. Considering the value of both datasets, we used information from both RFMOs and TMT to analyze the specifications of IUU vessels.

2.1. Status of IUU Vessel Listings by RFMOs and CCAMLR

2.1.1. Yearly Trends in IUU Vessels

Figure 1 shows that the number of IUU vessels did not exhibit a consistent decline. The data revealed temporary increases in 2015 and 2019, primarily owing to extensive cross-listing among RFMOs. This practice was more common from 2018 onward, with 2019 showing the highest level of cross-listing activity. A total of 494 vessels were listed as IUU vessels. However, when cross-listed entries were excluded, the actual number of unique IUU vessels was 205.

2.1.2. Distribution by Nationality of IUU Vessels

Individuals or entities that violate or circumvent fisheries management regulations frequently employ practices, such as registering their vessels under foreign flags (commonly referred to as “flags of convenience” [FoCs]), to facilitate activities that are often illegal [20]. Therefore, the flags of IUU vessels, both at the time of listing and prior to listing, were analyzed as presented in

Table 2. Status of flags at the time of and prior to RFMO IUU vessel listings (excluding duplicates).

Flag at the Time of Registration and Previous	Total	~2014	2015– 2019	2020– 2024
Total	205	51	94	60
(Ratio, %)	(100.0)	(100.0)	(100.0)	(100.0)
Unknown	106	29	65	12
(Ratio, %)	(51.7)	(56.9)	(69.1)	(20.0)
PSMA Non-Party	67	17	19	31
(Ratio, %)	(32.7)	(33.3)	(20.2)	(51.7)
PSMA Party	32	5	10	17
(Ratio, %)	(15.6)	(9.8)	(10.6)	(28.3)

.

The analysis revealed that among the 205 unique IUU vessels, 51.7% (106 vessels) comprised undetermined or unknown flags, 32.7% (67 vessels) were PSMA non-party vessels, and only 15.6% (32 vessels) were flagged to PSMA party states.

2.2. Status of IUU Vessels Listed by TMT

2.2.1. Yearly Trends in Vessels

Figure 2 shows all vessels listed as IUU vessels in their respective years, totaling 365 vessels. Similar to the RFMO data, no evident downward trend was observed. The temporary spike observed in 2005 was attributed to a substantial number of listings that year by various organizations: 49, 16, and 12 vessels by IATTC, NEAFC, and IOTC, respectively.

Figure 3 shows the number of delisted IUU vessels, calculated by subtracting the delisted vessels from the total listed in Figure 2, resulting in 196 vessels. Most IUU vessels listed between 2003 and the early 2010 s were likely delisted owing to flag management changes, decommissioning.

2.2.2. Distribution by Nationality of Vessels

Of the 365 IUU vessels, 182 vessels had identifiable flags, whereas 183 vessels could not be traced to a specific flag. The 182 flagged vessels represented 45 countries, exceeding the 33 countries identified in the RFMO data. The flag distribution by country is presented in Figure 4. Of the 365 vessels, 183 vessels (50.1%) were of unknown nationality, 86 vessels (23.6%) were flagged to PSMA non-parties, and 96 vessels (26.3%) were flagged to PSMA party states. This result contrasts with the RFMO data, where non-party flags accounted for an increased share of IUU fishing vessels. The discrepancy indicates that IUU vessels under party flags were more likely to be delisted owing to appropriate national actions, whereas non-party flagged vessels remained on the list, possibly due to a lack of effective enforcement. (For the full tabulated data, see Appendix A,

Table A1. Flag states of IUU vessels listed by TMT.

Flag states	Registered	Currently Listed	Delisted
Total	365	196	169
(Ratio, %)	(100.0)	(100.0)	(100.0)
Unknown	183	123	60
(Ratio, %)	(50.1)	(62.8)	(35.5)
PSMA Non-Party	86	31	55
(Ratio, %)	(23.6)	(15.8)	(32.5)
PSMA Party	96	42	54
(Ratio, %)	(26.3)	(21.4)	(32.0)

.)

2.3. Specification Analysis of IUU Vessels

2.3.1. Nationality-Based Distribution of IUU Vessels

According to TMT data, the average number of IUU vessels listed as IUU fishing vessels between 2003 and 2024 was 15.8 per year. By excluding the anomaly in 2005, which showed a sudden increase, the average was 12.7 vessels per year. This figure is similar to the recent three-year average of 12.3 vessels from 2022 to 2024, suggesting that IUU vessels have been consistently active.

PSMA non-party vessels predominated in the RFMO IUU lists, whereas PSMA party vessels were more prevalent in the TMT IUU list. However, TMT data showed that, except for China (PSMA party), India (PSMA non-party), and Sri Lanka (PSMA party), most countries had only one vessel listed, suggesting limited representation and concentration in a few states. The enforcement of the PSMA establishes international minimum standards, thereby denying stateless vessels port access or use worldwide. Enhancing measures against stateless vessels target vessels and operators that intentionally operate outside of legal frameworks [21].

Additionally, numerous vessels continue to evade PSMA regulations by registering under FoCs and targeting ports outside PSMA jurisdictions, which remain vulnerable to IUU activities owing to inadequate oversight [22]. Considering that vessels of unknown nationality are likely to be flagged under PSMA non-parties, a substantial proportion of IUU fishing activities originate from non-party states.

2.3.2. IUU Vessel Classification by Type

The classification of IUU vessels by type, based on TMT data, shows that most vessels listed as IUU at the time of registration were fishing vessels. Figure 5 shows the breakdown, with (a) indicating vessels currently listed as IUU and (b) indicating vessels that have been delisted. In both categories, fishing vessels were most prevalent. However, even a single reefer vessel can transfer large quantities of catch at sea from numerous fishing vessels, underscoring the need for continued monitoring and caution. (For detailed vessel type data, see Appendix A,

Table A2. Vessel types of IUU vessels listed by TMT.

Vessel Type	Registered	Currently Listed	Delisted
Total	365	196	169
(Ratio, %)	(100.0)	(100.0)	(100.0)
Fishing Vessel	249	124	125
(Ratio, %)	(68.2)	(63.3)	(74.0)
Reefer	27	13	14
(Ratio, %)	(7.4)	(6.6)	(8.3)
Unknown	87	59	28
(Ratio, %)	(23.8)	(30.1)	(16.6)
Other	2	0	2
(Ratio, %)	(0.5)	(0.0)	(1.2)

.)

3. Results of IUU Vessel Analysis

A comprehensive analysis was conducted to determine whether vessels flagged to PSMA parties or non-parties are more likely to be currently listed or delisted as IUU vessels based on the flags listed in RFMOs. ‘Currently listed’ means there is a high likelihood that vessel’s flag state has not taken appropriate action against IUU fishing. On the other hand, ‘delisted’ means there is a high likelihood that the country has taken appropriate action. The data used for the analysis were derived from the TMT database, which compiles IUU vessel lists registered by RFMOs since 2002 and are publicly available. The target groups were intended to be categorized as PSMA parties, non-parties, and unknown.

However, due to the limited statistical representation of the unknown category (single classification), it was integrated into the non-party group for analysis. This is because unknown flags are deliberately used to conceal vessel identity to engage in IUU fishing. Generally, vessels flagged to PSMA parties can at least be identified and monitored through the vessel monitoring system (VMS).

The analysis results showed statistically meaningful findings in the comparison of mean registration status of PSMA parties through the paired t-test and descriptive statistics by registration status.

3.1. Independent-Sample T Test

An independent-sample t-test was conducted, as shown in

Table 3. Comparison of means by PSMA membership status.

PSMA		N	Mean	SD	t	p
Registered	Non-party	19	14.16	41.71	1.311	0.197
	Party	27	3.56	5.53
Currently Listed	Non-party	19	8.11	28.44	1.174	0.247
	Party	27	1.56	5.26
Delisted	Non-party	19	6.05	13.62	1.529	0.134
	Party	27	2.00	2.04

, to analyze the mean differences in registration-related indicators between PSMA parties and non-parties. For the registration category, the mean for PSMA non-parties was 14.16 (SD = 41.72), higher than the mean of 3.56 (SD = 5.53) for parties. However, this difference was not statistically significant (t = 1.311, p = 0.197). In the delisted category, the mean for non-parties was 6.05 (SD = 13.62), compared to 2.00 (SD = 2.04) for parties, yet the difference was also not statistically significant (t = 1.529, p = 0.134). These results suggest that PSMA membership may lead to some differences in the number of registered, currently listed, and delisted vessels, but the differences were not statistically significant. Notably, the generally higher means and larger standard deviations among non-parties imply a possibility of greater variability between countries.

3.2. Paired-Sample T Test

To analyze the mean differences in registration-related indicators by flag for PSMA non-party, a paired t-test was conducted as shown in

Table 4. Comparison of means of PSMA non-parties.

		Mean	SD	t	p
Paired analysis	Registered	14.16	41.71	1.937	0.069
	Currently Listed	8.11	28.44
Paired analysis	Registered	14.16	41.71	1.242	0.230
	Delisted	6.05	13.62

. First, when comparing the differences between registered and currently listed cases, the mean for registered cases was 14.16 cases (standard deviation = 41.72), while currently listed cases had a mean of 8.11 cases (standard deviation = 28.44), and this difference showed a marginal statistical significance (t = 1.937, p = 0.069). This suggests that, among PSMA non-parties, the frequency of registered cases tends to be relatively higher than that of currently listed cases, but this tendency is limited in terms of statistical significance. In the comparison between registered and delisted cases, the mean for registered was 14.16 cases, while that for delisted cases was 6.05 cases, and the difference in means between the two items was not statistically significant (t = 1.242, p = 0.230). These results show that for PSMA non-parties, the number of registered cases is higher than the number of currently listed and delisted cases, but the difference is not statistically significant, and the variability (standard deviation) between individual countries was also quite large. Consequently, these findings may reflect differences in the level of policy implementation or the intensity of monitoring among these countries, indicating the need for country-specific case studies or complementary qualitative research.

A paired t-test was conducted as shown in

Table 5. Comparison of means of PSMA parties.

		Mean	SD	t	p
Paired analysis	Registered	3.56	5.53	5.099	0.000
	Currently Listed	1.56	5.26
Paired analysis	Registered	3.56	5.53	1.535	0.137
	Currently Listed	2.00	2.04

to analyze differences between countries regarding measures related to registered cases for PSMA parties. First, in the comparison between registered and currently listed cases, the mean number of registered cases was 3.56 (standard deviation = 5.53), while the number of currently listed cases was 1.56 (standard deviation = 5.26), showing that the number of registered cases was significantly higher (t = 5.099, p < 0.001). This suggests that the proportion of cases proceeding from registered to currently listed is low in PSMA member countries and that cases which have been registered are more likely to be terminated or deactivated than to be currently listed. On the other hand, in the comparison between registered and delisted cases, the mean number of registered cases was 3.56, and for delisted cases, it was 2.00. While there was a difference, it was not statistically significant (t = 1.535, p = 0.137). In other words, within PSMA member countries, there is no significant difference between registered and delisted cases, and the proportion of registered cases that eventually become delisted may remain relatively constant. These results indicate that PSMA member countries tend to have a relatively small number of registered cases, with only a few being maintained over the long term, while most eventually end. Especially, the significant difference from currently listed cases suggests that responses are more event-driven rather than based on a continuous monitoring system.

3.3. Descriptive Statistics by Registration Status

In the descriptive statistics analysis by registration status, clear differences were observed in registration-related indicators among countries depending on their PSMA membership status, as shown in

Table 6. Descriptive statistics by PSMA membership status and registration status.

		Registered		Currently Listed		Delisted
		Mean	SD	Mean	SD	Mean	SD
PSMA	No-party	14.16	41.71	8.11	28.44	6.05	13.62
	Party	3.56	5.53	1.56	5.26	2.00	2.04

. PSMA non-parties had an average of 14.16 registered cases, 8.11 currently listed cases, and 6.05 delisted cases, showing relatively high volatility. In contrast, PSMA parties had lower averages, with 3.56 registered cases, 1.56 currently listed cases, and 2.00 delisted cases, all noticeably lower than those of non-party countries. These results indicate that countries that have joined the PSMA implement more stringent and consistent management measures regarding registrations. In particular, the differences in the averages and standard deviations for the currently listed and delisted items indirectly demonstrate that PSMA parties have established a systematic and stable response mechanism against IUU fishing. Therefore, whether a country is a party to the PSMA can be interpreted as a factor that affects the strength and consistency of a party’s monitoring and control activities in fisheries management. In the future, the international community needs to seek ways to encourage participation to the PSMA and develop policy linkages for PSMA non-parties.

4. Limitations of the Current System

First, IUU activities involving PSMA non-party vessels continue unabated. Globally, internal port state risk decreased, driven by parties to the PSMA, while external risk increased primarily as a result of non-parties to the PSMA. High-risk fleets are now diverting to PSMA non-parties [6]. Specifically, based on the analysis of this study, vessels from non-party states may engage in unauthorized fishing on the high seas and enter non-party ports, where they may offload their catch without undergoing PSM.

Second, IUU fishing frequently involves the use of FoCs. Vessels previously engaged in IUU activities may conceal their operational histories or deliberately switch to non-party flags to evade PSMA regulations and continue illegal fishing operations.

Third, a high probability exists that vessels conducting or supporting IUU fishing activities are operating with their Automatic Identification System (AIS) deactivated. Countries with vast Exclusive Economic Zones (EEZs) encounter considerable challenges in conducting inspections using patrol vessels. Additionally, on the high seas, inspection activities by vessels from RFMO member states are limited. Therefore, detecting IUU vessels relies heavily on tracking systems such as AIS and the vessel monitoring system (VMS). However, IUU vessels frequently deactivate these tracking devices during their operations, complicating detection and enforcement efforts.

Fourth, the GIES data remain limited. Since the system was officially launched in December 2023, the volume of accumulated data remains low, and inconsistencies exist in the quantity and formatting of registered information. These issues hinder comprehensive data sharing and analysis among PSMA parties.

Fifth, institutional and technical capacity gaps exist among PSMA parties. In particular, developing countries and coastal states may lack adequate infrastructure and human resources, creating difficulties in implementing PSMA and operating within the GIES framework.

Sixth, interoperability between RFMOs, the Global Record (GR), and GIES is limited. Although mechanisms for information sharing exist among these entities, they cannot currently exchange data swiftly and in real time, which limits the effectiveness of coordinated monitoring and enforcement.

5. Solutions

First, the most critical need is the establishment of a global joint coalition, coordinated by the FAO, in collaboration with PSMA parties and RFMOs, to collectively identify, track, and rapidly exchange IUU fishing information. This coalition should also develop an integrated monitoring portal. Through this coalition, IUU vessel lists maintained by various organizations should be standardized, and the standardized data must be quickly and universally shared among all participating organizations and states. Ultimately, the coalition should serve as the central hub with the most up-to-date and comprehensive information, equipped to analyze vulnerable regions and directly monitor those areas. This requires advanced surveillance equipment and a centralized control tower. For example, the system must include capabilities to operate and analyze Earth Observation (EO) data via optical sensors and Synthetic Aperture Radar (SAR) satellite imagery.

Second, a thorough evaluation of the advantages and disadvantages of EO and SAR technologies is essential. There have been reports of cases in which SAR has been used to continuously track the routes of vessels suspected of engaging in IUU fishing [23]. As presented in

Table 7. Comparison of SAR and EO systems.

Category	SAR	EO
Operating principle	Radar signal reflection	Natural light (visible)
Observation conditions	All weather, nighttime	Daytime, clear weather only
Resolution	Medium to high (1–30 m)	High (up to 0.3 m)
Vessel identification capability	Shape and size	Shape, color, features
Advantages	Observation anytime	Visual evidence
Disadvantages	Complex, costly	Weather-dependent, costly

, both systems comprise strengths and weaknesses and should therefore be used complementarily. Both technologies have high operational costs and require a general estimate of vessel positions prior to observation. These constraints limit the ability of individual states to operate these technologies independently. Therefore, a mechanism should be established to receive initial position data from port states or maritime authorities within the EEZ, thereby enabling targeted monitoring. From a cost-effective perspective, open-source satellite imagery can be utilized. Alternatively, each PSMA party can make use of its existing marine weather observation satellites, which would also be a necessary measure. By conducting continuous monitoring of specific risk-prone areas within certain designated zones, the surveillance area can be reduced and cost reductions can be achieved. In particular, since information is lacking in the early stages, it is necessary to observe a wide area of seas; however, each party will have limitations in significantly increasing their contributions from the start, which is why this is necessary.

Third, mechanisms should also be developed within individual countries to allow for interagency information sharing. This includes building frameworks connecting coast guards, port authorities, and fisheries management agencies, ensuring end-to-end monitoring from at-sea operations through to landing and distribution. For example, when an unidentified vessel engaged in fishing activity is detected within an EEZ of the state, the coast guard should implement a system to report to the national port authority, enabling verification and follow-up actions.

Fourth, when VMS or AIS is deactivated, port entry should be conditionally allowed only after submission of complete route records. Vessels not on an IUU list but lacking AIS data from EEZ or high-seas segments should be prioritized for inspection by the port state.

Fifth, the coalition should investigate the status of PSMA non-party ports and the distribution and sale of fishery products in major landing ports. This will facilitate the identification and assessment of high-risk ports. Port states identified as high-risk should be placed under increased global scrutiny. Similarly, market states importing fishery products from such ports should implement stricter import procedures. For example, under a Catch Documentation Scheme (CDS), the port state must certify that all associated fishing vessels and reefers involved in the catch, transshipment, and landing were authorized, had no history of infractions, and exhibited no suspicious routing behaviors.

Sixth, efforts should be made to encourage PSMA non-party states to join the agreement. Successful international cooperation in addressing IUU fishing can be contagious, with effective measures adopted by one state or organization encouraging others to follow suit [24]. Non-party states listed in IUU vessel registries should be invited to relevant PSMA meetings to promote engagement and eventual accession. Lastly, programs should be implemented to enhance national inspection capacities. In addition, programs to provide technical and informational support should be developed to help PSMA parties reduce disparities in GR and GIES data. These could include technology transfers and training from FAO and developed countries, education programs on the use of GIES and GR, and incentives for PSMA parties excelling in information registration and compliance—promoting healthy competition and shared responsibility.

6. Conclusions

Proposing an Integrated Management Model Framework

While the proposed solutions address current challenges, an integrated system is essential for effective implementation, allowing more IUU vessels to be tracked and information to be shared promptly among port states. It is argued that overcoming the complexity of IUU fishing governance requires effective regulatory pluralism, in which multiple institutions and frameworks coordinate their efforts [25]. Therefore, the necessity of the integrated multi-tier cooperation model proposed in this study is further emphasized. Accordingly, we proposed a model framework for the integrated management of diverse systems and datasets, as shown in Figure 6.

This study proposed an integrated management model and a phased implementation plan to strengthen global efforts to combat IUU fishing. We recommended a three-step approach, as illustrated in Figure 7, starting with the most feasible measures and progressively enhancing cooperation and monitoring capabilities. In addition, the proposed framework incorporates a comprehensive set of control and management mechanisms designed to facilitate effective collaboration among multiple organizations, clarify institutional roles and responsibilities, and ensure consistent implementation across jurisdictions. These mechanisms aim to establish clear governance protocols, data security standards, and enforcement tracking systems, thereby reinforcing the operational feasibility and sustainability of the proposed integrated framework.

The proposed solutions address current system limitations, but as detection technologies advance, IUU fishing methods will also evolve. Therefore, it is imperative to periodically reassess existing frameworks and pursue next-generation monitoring systems. Global fisheries governance demonstrates how a state can leverage its political and economic influence to shape international anti-IUU norms and highlights that strengthening a state’s implementation capacity and commitment is crucial to eradicating IUU fishing [26]. Therefore, many countries should employ various means to demonstrate their determination and interest in eradicating IUU fishing, while also making dedicated efforts toward practical enforcement. Additionally, this study identified a significant number of unknown-flag vessels, making it difficult to reconcile the statistics across datasets, underscoring the need for more comprehensive and standardized datasets in future research.