Research Article  |   Maritime Science and Management

Assessment of Coastal Navigation Safety: A Case Study of Boka Bay with Stakeholder Perspectives 

BY Ivan Mraković, Rino Bošnjak

Keywords : Coastal navigational safety, Non-SOLAS crafts, Maritime questionnaire, Virtual AtoN

The navigational safety of Boka Bay, i.e., a critical maritime area along the Adriatic coast, is of great importance owing to its ecological sensitivity, diverse marine traffic, and significant economic activity. This study provides a comprehensive assessment by analyzing the perspectives of various stakeholders, including seafarers, local pilots, skippers, regulatory authorities, and others engaged in maritime activities within the bay. Using a structured questionnaire survey, both quantitative and qualitative data were collected in formats such as descriptive responses, Yes/No choices, and Likert scale ratings, ensuring a well-rounded understanding of navigational practices and challenges. The data were analyzed using descriptive statistics, correlation analysis, and regression analysis to assess the impact of key factors on navigational safety. The analysis revealed several key contributors to navigational risks, including the inadequate navigational aids, non-compliance with regulations, and growing traffic of non-SOLAS vessels. The findings highlight the critical need for improvements in navigational infrastructure and stricter enforcement of maritime safety protocols. The study concludes with actionable recommendations aimed at enhancing navigational safety, minimizing risks, and ensuring the protection of Boka Bay's unique environmental and economic resources while promoting sustainable maritime operations.

Research Article  |   Marine Biology And Ecology

DNA Barcoding in Species Identification of Flying Fish (Exocoetidae) and Halfbeaks (Hemiramphidae) Larvae: A Comparative Study of the Database Over a Decade

BY Hui-Ling Ko, Kwang-Tsao Shao, Ching-Yi Chen , Yen-Wei Chang

Keywords : Cushion mount, Carbon fiber reinforced polymer (CFRP), Finite element analysis (FEA), Experimental modal analysis (EMA), Frequency response function (FRF), Damping

The families Exocoetidae and Hemiramphidae comprise migratory species, whose identification based on their external morphological characteristics can be challenging because of their similarities. DNA barcoding has been used in taxonomic and evolutionary studies to address these issues. The morphological characteristics of fish larvae change rapidly and often lack distinctive features, posing a challenge for species-level identification. This study used DNA barcoding to identify flying fish and half-beaked larvae. Using plankton nets, sampling was conducted seasonally between 2010 and 2013 in Nanwan, Taiwan. A total of 903 individuals were collected, of which 111 were identified as f lying and half-beaked fish based primarily on morphological characteristics. The individuals were further classified into 18 distinct morphotypes. DNA barcoding was performed between 2011 and 2013 using the Taiwan Fish and Barcode of Life Data Systems (BOLD) database. Among the 18 morphotypes, 13 were identified at the species level, 3 at the genus level, and 2 at the family level. After a decade, we utilized a database and phylogenetic tree for reanalysis, enabling species-level identification. The species identification rate increased from 61.11 % to 100 %. Therefore, a robust database can improve species identification accuracy. DNA barcoding allows accurate identification of larval fish at the species level. The morphological characteristics of larval fish confirmed using DNA can be used for future morphological classification and research on their early life histories, including their spawning grounds, spawning seasons, and migratory distributions. This is crucial for resource management and sustainable utilization of flying fish fisheries.  

Research Article  |   Maritime Science and Management

Instruments Implementation Audits and Development Strategies for Taiwan as a Non-Member State of the IMO

BY Hui-Huang Tai, Tun-Hao Hsu

Keywords : IMO, Mandatory audit, III Code, Non-member state

The International Maritime Organization (IMO) has formulated numerous maritime-related conventions. The promotion of mandatory audits is required to ensure that the implementation of maritime management systems in various countries complies with the IMO Instruments Implementation Code (III Code) and that both member states and non- member states implement these conventions. This is not only an obligation but also a responsibility for all countries to promote the development of the maritime industry. This study investigates how Taiwan, one of the non-member state of the IMO, implements the audit process and develops future implementation strategies for various maritime conventions. This issue is of great significance to Taiwan as an important hub in the international maritime industry. The results of the study reveal that the proactive efforts of government authorities and officials and active participation in audits are considered the most crucial driving factors by most experts. However, more attention should be given to the challenging issues associated with international participation, which currently represent external threats and internal weaknesses. Furthermore, the continuous and proactive participation in audits of relevant IMO regulations is a key strategy for non-member states to maintain long-term strength in the maritime industry. Other non-member states can also refer to Taiwan's experience, strive to keep up with international standards, and seek to join the IMO to contribute to global maritime efforts. In addition, Taiwan's government should make better use of and continue to support Taiwan's maritime industry and strong private sector. Moreover, cooperation with international allies is a critical strategy for completing audits and sustaining the development of Taiwan's maritime industry. 

Research Article  |   Marine Engineering

Operational Risk Evaluation of Oil Tankers via Multivariate Gaidai Reliability Framework Incorporating Memory Effects

BY Oleg Gaidai, Shicheng He, Jinlu Sheng , Yan Zhu, Alaa Elsayed, Mahmoud El-Wazery

Keywords : Transportation, Crushed ice model, Oil tanker, Gaidai methodology, ANSYS/LS-DYNA, Ice-thickness distribution, Arctic navigation

The retreat of Arctic Sea ice may exert a major impact on economy，potentially transforming the nature of commerce between Asia, Europe, and the Americas. Projections indicate a 40% reduction in transit distance and a 30% decrease in voyage time between Europe and northwest Asia compared to traditional routes such as the Suez Canal. However, even during summer navigation, fragmented floating ice persists, generating stochastic ice loads on vessel bows and hulls through complex ship-to-ice interaction. For structural design, statistical extrapolation methods are required to accurately assess excessive areal bow/hull stresses. This study proposes a novel multi-modal structural damage risk assessment framework to evaluate extreme bow areal stresses in oil tanker traversing Arctic routes. The operational hazards assessment was performed in two distinct stages. In the first stage, the vessel areal stress distribution across the oil tanker’s bow/hull was assessed using the ANSYS/LS-DYNA software package. In the second stage, characteristic/design excessive bow/hull stresses were predicted by utilizing multi-modal Gaidai hazards assessment approach, with specified return periods of interest as input parameters. Realistic ice-thickness distributions were incorporated into the model as critical environmental input variables. Vessel routes are strategically selected to exploit ice thinning patterns during specific seasonal navigation windows. A key advantage of the proposed risk assessment methodology lies in its capacity to evaluate dynamic system risks for high-dimensional system with theoretically unbounded component interactions. This study aims to propose and validate a novel multi-modal Gaidai hazards assessment methodology for quantifying extreme bow/hull stresses in oil-tanker operating on Arctic routes.

Research Article  |   Ocean Science

Evaluation of Carbon Sequestration in Seagrass Meadows of Kenting: A Comparative Study with Penghu and Dongsha Island

BY Zih-Wei Tang, Huei-Fen Chen, Jordi Mahardika Puntu, Ping-Yu Chang, Li Lo, Jian-Jhih Chen, Wen-Chen Chou, Lan-Feng Fan, and Ying-Ju Chang

Keywords :  Seagrass, Carbon sink, Blue carbon, Sediment, Volume, Carbon storage

This study investigates the controlling factors of carbon sequestration (CS) in seagrass bed sediments across three distinct environments in Taiwan: the Kenting (KT) coastal area, the Penghu (PH) open inner bay, and the Dongsha (DS) Atoll lagoon. Actual measurements of the substrate depth beneath the sediment and ground-penetrating radar (GPR) scans of the beach reveal that the coral reef bedrock in KT slopes landward. A field survey of the seagrass area in KT was conducted, and three cross-sectional profiles were analyzed to determine their topography, yielding a median sediment thickness of 88.2cm. Based on these measurements, the sediment volume was estimated at 5.16 × 10¹⁰ cm³. By analyzing the total organic carbon (TOC) content of seagrass sediments, this study provides insights into how regional environmental conditions influence carbon storage in Taiwan’s seagrass meadows. Our results reveal significant regional variability, with sediment carbon storage reaching 49.0 MgC/ha in KT, over 13.2 MgC/ha in PH, and an exceptional 145.7 MgC/ha in the extensive seagrass meadows of DS. These findings underscore the critical role of environmental stability in enhancing carbon sequestration. In particular, the Dongsha Islands exemplify how regions with low wave energy offer favorable conditions for maintaining high carbon storage. Additionally, our analysis suggests that carbon from aquatic plant sources may have potential contributions in the KT area. Finally, this study also compares the global and regional contributions of seagrass beds to carbon storage, including examples from the Mediterranean region, Japan, Taiwan, and Thailand. Preliminary findings indicate that the carbon sink capacity of seagrass meadows in Asia is significantly lower. This observation warrants further investigation and continued research. 

Research Article  |   Other Related

Calculation of Aquifer Transmissivity from Borehole Resistance Measurements and Pumping Test Results

BY Fen-Rong Yang, Chien-Wei Huang, and Tien-Kuen Huang 

Keywords : Groundwater, Pumping tests, Transmissivity, Ground resistance surveys, Formation factor

Transmissivity is a crucial hydrogeological parameter for evaluating groundwater resources. This parameter is conventionally evaluated using pumping tests; however, these tests are costly and can be conducted at few sites. Many researchers have used ground resistance and pumping test data to estimate various hydrogeological parameters. In this study, borehole resistance survey and pumping test data collected by the Taiwan Groundwater Monitoring Network were used to establish the relationship between transmissivity and formation factor for aquifers in the Zhuoshui River alluvial fan. This relationship was then used to estimate the water output of the aforementioned aquifers in a cost-effective manner from the formation factor estimated through borehole resistance surveys. The results indicated that the shallower aquifer in the aforementioned alluvial fan exhibited its highest transmissivity in the top-fan area, whereas the deeper aquifer exhibited its higher and lower transmissivity in the northern and southern regions of the alluvial fan, respectively. These lower transmissivity distributions may be attributable to local land subsidence. Throughout the entire Zhuoshui River alluvial fan, the transmissivity and formation factor of aquifers at different depths could be favorably modeled by an exponential relationship. Furthermore, this relationship could be simplified into a linear relationship with a high coefficient of determination (0.84). The strong correlation between the transmissivity and the formation factor suggests that the proposed method is effective for reducing the cost of groundwater resource evaluation.

Research Article  |   Marine Engineering

Research on Multi-ship Collision Avoidance Decision-Making based on Improved Velocity Obstacle Method using Dynamic Elliptical Ship Domains

BY Tang Xinwei, Li Weifeng

Keywords : Velocity obstacle, Collision avoidance, Ship domain

The velocity obstacle method offers collision avoidance solutions for critical multi-ship encounter scenarios. This thesis introduces a Reciprocal Velocity Obstacle (RVO) approach based on dynamic elliptical ship domains for multi-ship collision avoidance. Initially, the concept of dynamic elliptical ship domains is presented, building upon the original static elliptical ship domain Velocity Obstacle (VO) method. Subsequently, multi-ship encounter scenarios are simulated in both virtual environments and real nautical charts, comparing the two methods. The analysis results demonstrate the improved method's excellent performance in both cases, underscoring its advantages. This research provides more effective collision avoidance strategies for multi-ship encounters.

Research Article  |   Maritime Science and Management

A Hybrid Model to Assess Commercial Port Resilience in Taiwan

BY Po-Hsing Tseng and James J.H. Liou

Keywords : Port, Resilience, BWM, Dombi, CoCoSo

Since 2021, international commercial ports have faced unprecedented challenges (e.g., COVID-19 pandemic, Suez Canal congestion), impacting daily life, work, human well-being, properties, the environment, and socio-economic activities. The adaptation capability resilience of international commercial ports to respond to external changes has become crucial. This study develops an expert knowledge-based hybrid multi-criteria decision-making model integrating Best-Worst Method (BWM), Rough Dombi Aggregator, and Combined Compromise Solution (CoCoSo) to evaluate port resilience capabilities, using Taiwan's international commercial ports as a case study. We propose four evaluation dimensions encompassing 13 indicators: detection capability, resistance capability, resource integration capability, and recovery capability. The BWM determined indicator weights, while the CoCoSo method explored gaps between alternatives and aspiration levels. The Rough Dombi Aggregator was used to integrate collected data, addressing expert uncertainty and inconsistent judgments. Results showed the top three weighted indicators are CIQS, Vessel Traffic Center, and human education and training. The CoCoSo analysis ranked port adaptation capability resilience as: Kaohsiung, Keelung, Taichung, Taipei, Anping, Hualien, and Suao. Management implications for improvement are provided. These findings can guide decision-making for international port authorities, shipping industry operators, and stakeholders.

Research Article  |   Maritime Science and Management

Exploring the Red Sea Crisis’s supply chain disruption impacts on the shipping industry

BY Po-Hsing Tseng and Nick Pilcher

Keywords : Red Sea crisis, Shipping, Supply chain, Grounded theory

Since October 7, 2023, the Houthi militia in Yemen has continuously attacked Israel and its nearby ships in the Red Sea. This crisis has impacted on global ship operations, freight rates, and shipping networks, since this conflict seriously affects the international trade between Europe and Asia and brings many unpredictable butterfly effects (e.g. supply chain disruption, and high transportation costs in shipping and air cargo). This papero explores its impact on the supply chain and suggests potential solutions;, and to consider perceptions on who should be responsible for the crisis, and who will actually shoulder the responsibility for the crisis. The potential extra fuel consumption is calculated using one real containership’s data in this paper. Also, theis paper adopts semi-structured interviews of nine shipping operators and four governmental officials from Taiwan to illustrate expert perceptions of this key shipping area, and analyses and summarizes the research findings using grounded theory analysis. Results provide the latest insights and operational decision analysis suggestions for shipping operators and relevant stakeholders.

Research Article  |   Other Related

Key Steering Characteristics for Training Remote Operators of Maritime Autonomous Surface Ships in Collision Avoidance

BY Soyeong Lee,  Ik-Hyun Youn

Keywords : Maritime Safety, Collision Avoidance, Remote Operation, Maritime Education and Training

Maritime Autonomous Surface Ships (MASS) require remote operators (ROs) who need to be trained in collision avoidance (CA) maneuvers. In order to develop a training system, this study investigated differences in the steering characteristics of expert and novice navigators such as the timing of the initial rudder operation, rudder angle at a relative bearing 0°, heading at the maximum rate of turn to starboard, and, heading at the closest point of approach. The experts exhibited relatively consistent and controlled steering patterns characterized by earlier rudder adjustments and smoother heading transitions while novices demonstrated delayed reactions and greater variability in heading changes. These results were used to develop guidelines for ROs to execute CA maneuvers safely and efficiently.

Research Article  |   Maritime Science and Management

Subsurface Origin of TEX₈₆ Signals Revealed by Cross-seasonal GDGT Distributions in Suspended Particulate and Sediment Samples From the Southern East China Sea

BY Hung-Lin Tsai, Da-Cheng Lin

Keywords : TEX ₈₆ , GDGT, Sub-sea surface temperature

The TetraEther indeX of 86 carbon atoms (TEX₈₆) proxy, which is based on isoprenoid glycerol dialkyl glycerol tetraethers (isoGDGTs) produced by Thaumarchaeota in marine environments, is widely used to reconstruct past sea surface temperatures (SSTs). However, evidence suggests that this proxy often instead reflects subsurface conditions, particularly in dynamic marginal seas. Therefore, we conducted a cross-seasonal study of glycerol dialkyl glycerol tetraether (GDGT) distributions in the southern East China Sea (ECS), which is characterized by strong monsoonal and current-driven hydrographic variability. We analyzed surface sediments and the high-resolution vertical profiles of suspended particulate matter (SPM) collected from 2016 to 2022. Our results indicate that the sedimentary TEX₈₆ values correlated more closely with annual mean subsurface temperatures (subT) than with SSTs. The concentrations of isoGDGTs consistently peaked between 100 and 150 m, with limited seasonal variation. Linear regression overestimated SSTs, with BAYSPAR Bayesian calibration yielding values matching the observed subT, particularly at isoGDGT production depths. These findings suggest that the TEX₈₆ calculations integrate a stable subsurface signal rather than capture transient surface variability. This study observed a resemblance between SPM and sediment TEX₈₆, indicating that vertical transport dominates the delivery of GDGTs to the seafloor. Overall, our findings underscore the importance of identifying the subsurface origin of TEX₈₆ signals and indicate that BAYSPAR calibration should be used in marginal sea environments. This study provides key cross-seasonal evidence of GDGT stratification in the ECS and refines TEX₈₆-based paleotemperature reconstructions in climatically sensitive western Pacific settings.