The pioneering effort of Korea's distant water fisheries can be traced back to 1957 when Jinam-ho, affiliated with Jedong Industry Co., embarked on a tuna longline sea trial in the Indian Ocean. The success of this sea trial holds significant importance as it laid the groundwork for Korea to venture into the Pacific tuna fishing grounds, which were predominantly dominated by the United States and Japan at that time. The Korean distant water fisheries experienced remarkable growth in a short period, from the inception period in the 1950s, the pioneering period in the 1960s, the growth period in the 1970s, and the development period in the 1980s. However, a series of changes in the international situation, including the global oil crises of 1973 and 1978, the declaration of 200-nautical-mile zones by coastal states in 1977, and the adoption of the United Nations Convention on the Law of the Sea (UNCLOS) in 1982 and the United Nations Fish Stocks Agreement (UNFSA) in 1995, made a significant transformation in the Korean distant water fisheries inevitable. In particular, UNFSA grants the authority to conserve and manage fisheries resources to the Regional Fisheries Management Organizations (RFMOs), and stipulates that coastal states and fishing nations cooperate with each other through RFMOs. In order to reclaim the once vast fishing grounds and secure maritime territories, it is imperative to have both the keen attention of the fishing industries and the strategic support of the government. In addition, to secure competitiveness in the international community, we should faithfully fulfill the role as a responsible fishing nation and contribute to RFMOs by strengthening scientific activities.

After the United Nations Convention on the Law of the Sea (UNCLOS) and the United Nations Fish Stocks Agreement (UNFSA) came into effect, international cooperation through Regional Fisheries Management Organizations (RFMOs) was required, and each RFMO established and adopted the Conservation and Management Measure (CMM) for the regional Observer Programs to collect data on fishing activities and biological information and to monitor compliance with its CMMs. The observer coverage required by RFMO is set differently for each organization, ranging from 5% to 100%. In addition, tuna-RFMOs recommend increasing observer coverage in longline fisheries by at least 20% for reliable quantitative analysis of not only target species but also bycatch species and ecologically related species such as sharks, seabirds, sea turtles, and marine mammals. Therefore, in this study, we discussed ways to improve the national observer programs of Korean distant water fisheries that should be addressed in the future to respond to the RFMO trends.

The IUU Fishing Index is composed of 40 indicators. These indicators were grouped by state responsibilities (flag, coastal, port, and general including market) defined in the FAO IPOA-IUU (2001) and then by type into vulnerability, prevalence, and response. A total of 152 coastal nations was surveyed. Korea's total combined IUU Fishing Index was 2.49 in 2019 and 2.91 in 2021, indicating a drop in the ranking to the third worst out of 152 countries followed by China and Russia in 2021. The indicators that increased the IUU fishing risk in 2021 compared to 2019 included seven indicators of prevalence and two indicators of response while those reducing the risk included one prevalence and one response indicator. The IUU Fishing Index revealed that many fisheries observers and monitoring, control and surveillance (MCS) practitioners active in the waters of RFMOs jurisdiction where Korean distant water vessels operate have mentioned concerns about the compliance with RFMO conservation measures or fishing practices. It suggested that strengthening management intervention in the fishing sector is needed. The primary tool for management is the MCS system. Given the logistical difficulty of oversight from land, air and at-sea, there is a need to enhance MCS strategies through logbook data, at-sea observer and electronic monitoring program. It also suggested that MSC fisheries certification and fisheries improvement projects, which are widely used for improving fishing sector performance, could contribute to the eradication of IUU fishing and the promotion of sustainable distant water fisheries.

Tuna fisheries were applied to an integrated ecosystem-based fishery risk assessment method using indexes of target species status, inhabited species in a target ecosystem, habitat quality and socio-economic benefit of affected fisheries. This study suggested more effective and efficient management measures to break away from traditional management methods, such as limitation of catch and fishing effort. The results presented that the objective risk index (ORIS) on sustainability of bigeye and yellowfin tunas by purse seine fishery was estimated high due to the high catch ratio of small fishes. The ORIs of biodiversity (ORIB) and habitat quality (ORIH) of purse seine fishery were also estimated at a high level from using fish-aggregating devices (FAD). However, due to skipjack tuna’s high catches, the ORI of socio-economic benefit (ORIE) was estimated at a very low level. Due to the high bycatch rate, ORIB was high, and ORIS and ORIH were evaluated at a low level in longline fishery. Due to strengthern of fishing restrictions and increase of fishing costs, the ORIE was assessed to be very high. The ecosystem risk index (ERI) for two tuna fisheries was assessed low, but the overall FAD management by purse seine fishery is necessary at the ecosystem level.