Kyung-Jin Ryu

Assessing occupational workload under dynamically unstable offshore conditions is challenging because physiological demands and biomechanical exposures may vary across tasks and may not be adequately characterized using a single measure. This exploratory field study characterized physiological, ergonomic, and kinematic workload during coastal gillnet fishing using an integrated assessment approach. Four fishermen (one captain and three crew members) were monitored during three fishing sessions under real offshore conditions. Heart rate, physical activity, ergonomic exposure using the Quick Exposure Check, and lumbar–pelvic kinematics using inertial measurement units were assessed across operational phases. Workload was temporally concentrated during hauling, with heart rate and physical activity increasing particularly during the mid-to-late hauling stages. Ergonomic exposure of the lower back, shoulder/arm, and neck also increased during hauling. Kinematic analysis revealed moderate trunk flexion accompanied by non-neutral flexion exposure of up to 28.62%, while the lumbar contribution to lumbar–pelvic motion frequently exceeded 50%. These findings suggest that integrating wearable sensing with ergonomic assessment may help characterize task-specific workload patterns that are not readily captured by average physiological intensity alone. This approach may support field-based occupational workload assessment in dynamically unstable working environments.

Advanced time series interpolation techniques used for estimating marine environmental factors encounter challenges regarding their usability, practical implementation, and reproducibility outside of marine science laboratories. This study aimed to interpolate NIFS Serial Oceanographic Observations and develop a system for analyzing complex factors in offshore and coastal fishing ground formation in South Korea. Additionally, the study explored the potential for integration of spatiotemporally discontinuous in situ data with continuously available satellite data through interpolation methods. Specifically, daily sea temperature and salinity data were generated through conventional time series interpolation techniques such as linear, cubic spline, and STL + PCHIP, and spatial interpolation techniques such as IDW, kriging, and natural neighbor were used to construct monthly raster data. The generated data were compared with the output of the GOFS3.1 model, and statistical indices such as MAE, RMSE, R², and Pearson or Spearman correlation coefficients were used to evaluate the accuracy and reproducibility. Cubic spline temporal and kriging spatial interpolation methods demonstrated strong performance for the sea temperature data; however, the interpolation performance for the salinity data exhibited limited effectiveness owing to unique local variability. This study introduces techniques for transforming discontinuous in situ observational data into high-resolution data and demonstrates that the integrated use of in situ data can enhance our understanding of the fishing ground formation mechanisms and ecosystem-based fishery management.

Open-sea fishing vessel accidents are difficult to assess systematically because no state holds exclusive jurisdiction, and reporting and investigative duties are not applied consistently. This study analyzed 67 officially reported accidents from the International Maritime Organization (IMO) Global Integrated Shipping Information System (GISIS) using a bow-tie framework combining fault tree analysis (FTA), Firth logistic regression, event tree analysis (ETA), and quantitative risk assessment (QRA). COLREG violations and watchkeeping failures dominated collisions; overload and stability issues caused capsizes; pump capacity, hull leakage, and vessel aging (≥30 years) caused sinkings. Firth regression confirmed older vessels and high beam-to-length ratios (≥0.30) significantly increased sinking likelihood. ETA and QRA estimated probabilities of 0.522 for collisions, 0.090 for capsizes, and 0.388 for sinkings, with risks of R = 0.155, 0.048, and 0.036. Because open-sea accident data rely on limited and voluntary reporting, results are preliminary. However, the bow-tie framework effectively identifies dominant causal factors and high-severity event pathways in open-sea fishing operations.

The Korean aquaculture sector relies heavily on foreign workers, who face elevated risks due to language barriers and limited safety training. This disparity necessitates data-driven safety interventions addressing specific worker vulnerabilities to ensure sustainable industry growth. This study quantitatively investigated accident characteristics and economic losses by nationality in Korean aquaculture by integrating 325 approved cases (2018–2022) from Industrial Accident Compensation Insurance (268 Korean; 57 foreign) and field survey data into the Formal Safety Assessment and Fault Tree Analysis frameworks recommended by the International Maritime Organization (IMO). The study revealed that entanglement during machinery operations accounted for 63.5% of the total cost among foreign workers. For Korean workers, slip and fall accidents were most frequent, while falls from height were the most severe in terms of unit cost and fatality. Based on the importance index and Human Element analysis, four risk control options were proposed: guarding and interlocks retrofit, multilingual training for foreign workers, and fall-protection upgrades and permit-to-work systems with lockout/tagout for Korean workers. Scenario analysis demonstrated consistent cost-saving effects. Both direct and indirect costs were incorporated into total loss estimation, with indirect costs calculated as 0.5–1.0 times the direct costs following the Ministry of Employment and Labor (2021).

Sea anchors for fishing operations are essential equipment to enhance catch efficiency and ensure operational stability at sea. However, previous studies have mainly focused on theoretical modeling or experiments under restricted conditions, which have not sufficiently reflected the complex operating environments and practical needs of real-world fisheries. To address this gap, this study derived key factors to improve the design and operation of sea anchors and quantitatively analyze the relative importance and rank of these factors. An expert panel was formed from 25 participants, including jigging vessel captains, recreational fishing boat captains, sea anchor manufacturers, and research institute workers. Using a three-round Delphi process followed by Analytic Hierarchy Process (AHP) analysis, we distilled an initial list of 52 improvement suggestions into 15 prioritized items, quantitatively ranked by relative importance based on expert consensus. The highest-ranked factor was ‘Enhancement of fabric drying performance’, followed by ‘Application of low-cost, high-efficiency materials’, ‘Improvement of recovery’, ‘Enhancement of UV resistance’, and ‘Product quality certification’. The highest-weighted metric was ‘Improvement of usability’, followed by ‘Enhanced durability’ and ‘Improvement of functionality’. The consistency ratio (CR) of the pairwise-comparison matrix was 0.0014 (AHP acceptability criterion: CR ≤ 0.1), confirming the reliability and consistency of the analysis. By reflecting real-world priorities through a robust and systematic analytical process, this study offers a foundation for evidence-based improvements in sea anchor design and operation, overcoming the limitations of earlier approaches rooted in subjective judgment or trial-and-error experience.

Worker safety has been relatively overlooked in the rapidly growing aquaculture industry. To address this gap, industrial accident compensation insurance data—mainly from floating cage and seaweed farming—were analyzed to quantify accident types and frequencies, with a focus on human elements as root causes. Basic causes were selected based on IMO Resolution A/Res.884 and assessed through a worker awareness survey. Fault Tree Analysis (FTA), a Formal Safety Assessment technique, was applied to evaluate risks associated with these causes. The analysis identified organization at the farm site (23.3%), facility and equipment factors (22.8%), and people factors (21.4%) as the primary causes. Among secondary causes, personal negligence (13.2%), aging gear and poor maintenance (11.4%), and insufficient risk training (10.4%) were the most significant. Selective removal of these causes reduced the probability of human element-related accidents from 64.6% to 48.6%. While limited in scope to Korean data and self-reported surveys, the study demonstrates the value of combining quantitative data with worker perspectives. It provides foundational data for developing tailored safety strategies and institutional improvements—such as standardized procedures, multilingual education, and inclusive risk management—for sustainable safety in aquaculture.

Fisheries and Aquatic Sciences

Fisheries and Aquatic Sciences

Sea anchors are crucial for stabilizing fishing vessels and improving operations, specifically for jigging vessels. Their effective performance depends on design and material choice, with the canopy material playing a key role. We compared the drainage and drying rates of sea anchor canopies made from polyamide (PA) fabric, polyester (PES) fabric, and canopies designed with alternating strips of PA and PES (PA-PES) fabric to improve sea anchor performance, work efficiency, safety, and the stability of fishing operations. PA fabric had a fast initial draining rate due to high seawater absorption but a slow drying rate, resulting in a heavy canopy. PES fabric showed optimal draining due to low seawater absorption and fast drying. PA-PES fabric showed intermediate performance. Statistical analyses revealed that Sample B performed significantly better than PA fabric and PA-PES fabric, which showed no significant differences in performance. The low absorption and fast drying properties of PES fabric enhance the handling and efficiency of sea anchors, reducing worker fatigue and improving safety. These characteristics make it an exceptional alternative to PA fabric for sea anchor canopies. Future studies should examine the roles of sea anchor canopy material and structure in fishing operation safety and efficiency.