This study aimed to enhance the operational efficiency and safety of offshore eel trap fisheries by developing six types of automated fishing equipment: a bait crusher, bait cutter, main line arranging device, trap cleaning device, eel sorting device, and fish pump system. Sea trials demonstrated that the bait crusher and bait cutter significantly reduced manual labor and processing time while maintaining bait quality. The main line arranging device improved productivity and safety by automating the sorting of looped cords. The trap cleaning device effectively removed fouling organisms using high-pressure water and rotating brushes. The eel sorting device enabled automatic size-based selection, improving resource management and operational efficiency. The fish pump system transferred eels rapidly with minimal physical damage, reducing unloading time by over 80% and decreasing labor requirements. A satisfaction survey of fishery participants confirmed that all developed devices were highly effective in reducing workload, enhancing safety, and improving operational performance. The automated equipment developed in this study is expected to contribute to the sustainable management of offshore eel trap fisheries and to offer potential applicability to other coastal and offshore fisheries.

This study examined the offshore eel trap fishing process using one year of fishing logs and fishermen’s insights to identify key operational challenges and propose equipment improvement for greater efficiency and safety. Conger eel catches varied significantly by season, depth, and temperature, peaking in winter at 85–90 m and 23°C. The western waters of Jeju Island were identified as a major fishing ground, with the highest catch recorded in November and the lowest in July, reflecting seasonal trends. Each fishing operation deployed about 10,000 traps, with an average loss of 38 traps, posing economic concerns. The process involved intensive manual labor in bait preparation, trap retrieval, catch separation, line loading, and unloading, leading to high physical demands and safety risks. To address these issues, the study proposed automation through the development of a line loading device, trap cleaning device, bait processing machine, and automatic catch separator. These innovations could reduce the labor force required by one to two workers per process, alleviate workloads, and enhance resource management. By integrating quantitative logbook analysis with field-based knowledge, this study offers practical value. Further research is recommended on automation development, cost-effectiveness, and field validation to support safer and more sustainable eel trap fisheries.

특정 선박의 조종성능이 실질적으로 제한되어 있는지 여부는, 특정한 선박을 기준으로 해당 선박의 기능적 특성과 운항 당시의 환경을 종합적으로 고려하여 판단하여야 하는 상대적 개념이다. 어로에 종사하고 있음으로 인해 조종성능이 실질적으로 제한되어 있는지 여부를 다른 선박이 명확히 판단하는 것은 용이하 지 않다. 따라서 해상교통안전법 제83조의 적용에 있어서는 특정 선박이 자신 의 항법상 지위를 정확히 판단한 후 이에 부합하는 등화 및 형상물을 표시하는 것이 무엇보다 중요하다. 다수의 재결에서 해양안전심판원은 통발조업 어선의 법적 지위를 어로에 종사하고 있는 선박으로 인정한 사례가 있지만, 일부 재결에서는 이에 반대되는 사례도 있다. 그러나 위와 같은 해양안전심판원의 재결 은 개별 사안에서 구체적 타당성을 고려한 심판원의 고민의 결과라고 해석하는 것이 타당하다. 어업실무상 통발조업에 사용되는 통발의 종류는 다양할 뿐만 아니라 규격화되어 있지 않다는 점과 통발을 사용하여 어획하는 어류도 다양하 다는 점을 고려하면, 유사한 성능을 가진 선박이 유사한 환경에서 통발조업을 하더라도 해당 선박의 항법상 지위에 관해 항상 동일한 결론이 도출된다고 보 기는 어렵다. 해양안전심판원은 일부 재결을 통해, 어로에 종사하고 있는 선박 의 판단기준으로서 사고 당시 선박의 침로나 속력의 변경 가능성 외에 적극적 인 피항동작으로 인한 어구 등의 손상 가능성을 고려하고 있다. 그렇다면 통발 조업 어선의 어로에 종사하고 있는 선박으로서의 지위에 관해서는 향후 심판원 의 재결을 통해 해당 문제에 대한 명확한 입장 표명이 요구된다.

This study analyzed the catch data of Chionoecetes japonicus in the offshore trap fishery from 2009 to 2022 to investigate the spatial distribution changes of fishing grounds in the East Sea. The results showed that the center of the fishing grounds consistently shifted offshore and northward from 2009 to 2020, but moved back towards the coastal areas since 2020. When comparing the catch of C. japonicus from the offshore trap fishery between 2009-2015 and 2016-2022, statistically significant differences were found (p<0.01). Analysis of the center of the fishing grounds revealed that they gradually shifted offshore while the fishing grounds were initially concentrated in the coastal areas of the East Sea. This suggests that the center of the fishing grounds moved offshore and northward as the C. japonicus in the coastal fishing grounds decreased. The shift of the fishing grounds back towards the coastal areas since 2020 is attributed to the increased operational costs due to the soaring fuel prices and the impact of the COVID-19 pandemic, which led to a decline in consumer demand for live seafood consumed in restaurants. Consequently, the offshore trap fishery for C. japonicus shifted their focus from offshore areas, which required higher operational costs due to increased fuel consumption and longer fishing times, to coastal areas, that were relatively less costly. This study is the first scientific results of its kind to investigate the formation of fishing grounds and annual changes in the fishing grounds of C. japonicus caught in offshore trap fishery in the East Sea from 2009 to 2022.

This study analyzed the selectivity of Octopus minor using the extended SELECT model in netpots. The data used for the analysis were collected from ten sea trials conducted between 2009 and 2010 using cylindrical octopus traps with six mesh sizes (16, 18, 20, 22, 24, and 26 mm). The selectivity analysis was performed using two models: the p-fixed split model and the p-estimated split model, depending on whether the encounter probability (split parameter) was estimated. The model fit was evaluated by comparing the model deviation and AIC values. The results showed that octopus catch decreased as mesh size increased, with a general tendency for larger individuals to be caught. The 16 mm trap, which had the smallest mesh size, accounted for 25.9% of the total octopus catch by number of individuals while the 22 mm trap, a commercial mesh size, accounted for 14.1%. The CPUE based on weight was highest for the 18 mm trap. The selectivity analysis results indicated that the p-estimated split model provided the best fit, and the 50% selection length for the 22 mm trap was 64.57 mm. In this study, reliability of various models was considered in the mesh selectivity analysis, and the findings are intended to serve as basic data for improving relevant regulations and deriving scientific research results.

To analyse and review the fishing performance and species composition according to the size of the entrance and mesh of the pot in the southern coastal waters (Tongyeong, Gyeongsangnam-do and Yeosu, Jeollanam-do), the experiment in this study caught one class, eight orders, 17 families, 23 species, 662 fishes, and 99,833 g. The largest number of fish species was Conger myriaster (301 fishes caught) accounting for 45.5%, followed by Octopus vulgaris (152) accounting for 23.0%, Charybdis japonica (45) accounting for 6.8%, Sebastiscus marmoratus (43) accounting for 6.5%, and Parapercis sexfasciata (42) accounting for 6.3%. Conger myriaster, Octopus vulgaris, Charybdis japonica, Sebastiscus marmoratus, and Parapercis sexfasciata accounted for 88.1% of the total catch. For other fish species, 68 fishes of 18 species were caught, accounting for 12.5% of the total. As a result of the total catch survey, the catch rate of Conger myriaster was the highest at 50.9% in B. 22 mm/280 mm. In addition, the average total length per fish increased as the entrance size increased. The weight ratios of Conger myriaster, Octopus vulgaris, and other fish species based on the total weight caught in each pots of the six species of test fishing gear are as follows. A pots 66.6%, 26.5%, 6.9%, B pots 57.2%, 24.5 %, 18.3%, C pots 43.2%, 31.5%, 25.3%, D pots 7.4%, 56.7%, 35.9%, E pots 43.6%, 0%, 56.4%, and F pots 5.0%, 79.6%, 15.4%.

This study employs Bayesian network analysis to quantitatively evaluate the risk of incidents in trap boats, utilizing accident compensation approval data spanning from 2018 to 2022. With a dataset comprising 1,635 incidents, the analysis reveals a mortality risk of approximately 0.011 across the entire trap boat. The study significantly identifies variations in incident risks contingent upon fishing area and fishing processes. Specifically, incidents are approximately 1.22 times more likely to occur in coastal compared to offshore, and the risk during fishing processes outweighs that during maintenance operations by a factor of approximately 23.20. Furthermore, a detailed examination of incident types reveals varying incidence rates. Trip/slip incidents, for instance, are approximately 1.36 times more prevalent than bump/hit incidents, 1.58 times more than stuck incidents, and a substantial 5.17 times more than fall incidents. The study concludes by providing inferred mortality risks for 16 distinct scenarios, incorporating fishing areas, processes, and incident types. This foundational data offers a tailored approach to risk mitigation, enabling proactive measures suited to specific circumstances and occurrence types in the trap boat industry.

The United States enforces the seafood import regulations so-called the Marine Mammal Protection Act (MMPA), and by 2023, all exports of aquatic products and processed fish products by fisheries which have not obtained an “Comparability Finding” from the National Oceanic and Atmospheric Administration will be completely banned. Therefore, to respond to the US MMPA, it is critical to identify technologies and methods used in worldwide for reducing bycatch of marine mammals. In particular, marine mammals are frequently caught in five fisheries (trawl, gill net, trap, stow net and set net) in Korea, which is facing a great challenge. This study presented bycatch reduction methods by five fisheries, classified the methods by country, and suggested appropriate reduction methods which can be applied in Korea.

In this study, for the purpose of reducing the catch of small giant octopus in a net pot, an escape experiment of octopus was performed on five types of escape rings of different sizes. As a result of the experiment, the smallest giant octopus with a weight of 406 g was found to escape from an escape ring with a diameter of 30 mm or larger, and 592 g octopus, a weight similar to the octopus of the current minimum landing weight (600 g), escaped from an escape ring with a diameter of larger than 40 mm. An individual weight with 406 g becomes 39 mm when converted from a diameter of 25 mm circular escape vent; that is, the circumference to the inner diameter of the mesh. It can be inferred that the converted mesh size of 39 mm cannot escape. Logistic regression analysis was performed using a generalized linear model (GLM) to investigate the correlation between the ratio of escape ring size/Mantle diameter (R/MD) and the escape rate. As a result, it was found that there was a significant correlation between the R/MD ratio and the escape rate and that the higher the R/MD ratio, the greater the escape rate. As a result of logistic regression analysis, the R/MD value was denoted 0.520 with the 50% escape rate. In addition, it can be estimated to be about 50 mm when converted to the mesh size. Therefore, in this study, the diameter of the escape ring and the size of the escape possible of the octopus were experimentally considered. It was found that there was a significant correlation.

Fisheries is known as a high-risk industry in Korea, and various efforts have been made to reduce occupational accidents. Trap fisheries represent crustacean production, accounting for 4.7% of total fisheries production and 10.7% of its production value, which is classified as a relatively high-risk industry. With the disaster insurance payment data of the National Federation of Fisheries Cooperatives (NFFC) from 2016 to 2020, the accident rate of the entire fishery, the accident rate of trap fisheries, and the type of disasters in the past five years were analyzed. As a result, the average fishery accident rate for the past five years was 5.31%, but it was high at 6.15% for coastal trap fisheries and 5.59% for offshore trap fisheries. Slips and trips, struck by objects and contact with machinery were the most common types of the accident according to the characteristics of the work, and hand injuries were analyzed the most. Additional efforts, including education for accident prevention, development of personal protective equipment and improvement of the working environment, are needed to prevent accidents caused by repeated types of disasters.

In this study, the fishery status of the octopus pot fishery in the east coastal sea were investigated, and the fishing performance of each pot shape was compared and analyzed. The fishery status survey was conducted through listening surveys at Jukbyeon Port, Uljin Port and Pohang Daebo Port in Gyeongbuk Province, and the amount of fishing gear used, fishing method, size and loss of octopus pot fishery was investigated. On the east coastal sea, octopus is one of the commercially important fish stocks and is caught in inshore pots, inshore combos, inshore gillnets and offshore pots. Among these fishing methods, pot fishing yields the highest catch. The shape of the pot differs depending on the region. In Uljin (Jukbyeon Port and Hupo Port), Gyeongbuk, rectangular type net pots are mainly used, and in Pohang (Daebo Port) in Gyeongbuk, drum-type pots are mostly used. Enteroctopus dofleini accounts for more than 90% of the catch of octopus. For the octopus fishing performance test by trap type, three types of traps (rectangular pot, drum pot and cylinder pot) were used on the coastal sea of Pohang Daebo. As a result, the total catch by pot shape was shown in the order of rectangular-type pot > drum-type pot > cylinder-type pot. The catch of octopus, the target species, was in the following order: rectangular-type pot > drum-type pot > cylinder-type pot. Such result shows a significant difference (Mann-Whitney test, p<0.05).