Marine Environmental Management Research Articles

Detection of mussels contaminated with cadmium by near-infrared reflectance spectroscopy based on RELS-TSVM.

Eating mussels contaminated with cadmium (Cd) can seriously harm health. In this study, a non-destructive and rapid detection method for Cd-contaminated mussels based on near-infrared reflectance spectroscopy was studied. The spectral data of Cd-contaminated and non-contaminated mussels were collected in the range of 950-1700nm. The model based on a robust energy-based least squares twin support vector machine (RELS-TSVM) was established to detect Cd-contaminated mussels. The influence of parameters on the RELS-TSVM model was analyzed, and the most suitable parameters were determined. The average accuracy of the proposed RELS-TSVM model in detecting Cd-contaminated mussels reached 99.92%, which was better than other twin support vector machine-derived models. For test datasets with different kinds of spectral noises (Gaussian noise, baseline shift, stray light, and wavelength shift), the RELS-TSVM model had a high robustness for noise disturbance. The results show that near-infrared spectroscopy combined with the RELS-TSVM model can realize the detection of Cd-contaminated mussels, which can provide technical support for the monitoring of heavy metals in shellfish. PRACTICAL APPLICATION: The method of detecting Cd-contaminated mussels by the NIRS has important practical significance for ensuring the safety of consumers. It provides a new way for the quality assessment and safety detection of shellfish and provides a technical basis for the marine environment assessment and management.

Embryonic and Pre-Larval Developmental Patterns in Cryptocentroides arabicus (Teleostei, Gobiidae).

The Arabian goby, Cryptocentroides arabicus (Gobiidae: Gobiinae), is a significant species in marine and brackish water ecosystems. However, limited information is available about the reproductive biology and the early life history of this species. This study aimed to understand the embryonic and pre-larval development of C. arabicus under controlled laboratory conditions using light microscopy. Ten fish pairs were placed in five 70-L glass aquaria, and environmental parameters were carefully monitored. After 4 months, spawning began, with each event yielding between 700 and 1500 eggs, totaling 10 spawning events. The elliptical-shaped eggs, measuring 3.9 ± 0.1 mm in length and 1.6 mm in maximum width, hatched after 7 days and 4 h at a water temperature of 28°C. This process resulted in the identification of eight distinct larval developmental stages. Parental care by both the male and female was observed during the incubation period. Documenting the morphological changes during incubation contributes to a better understanding of the reproductive behaviour and early life history of C. arabicus. This is essential for the conservation management of marine and brackish water environments.

The effects of changes in the coastline and water depth on tidal prism and water exchange of the Laizhou Bay, China

Laizhou Bay’s coastline has undergone multiple alterations due to human activities such as land reclamation and port construction. These changes in the coastline have led to modifications in the bay’s hydrodynamic conditions, which, in turn, can impact the marine environment and potentially result in a decline in biodiversity. To date, there has been no comprehensive study focusing on the coastline changes and hydrodynamic variations in Laizhou Bay. Therefore, this study utilizes coastline and water depth data from four time points—1990, 2003, 2013, and 2023—to establish a two-dimensional tidal current model of Laizhou Bay using Delft3D. Based on the good agreement between the simulated tidal current results and the observed data, this study further investigates the changes in tidal prism and water exchange in Laizhou Bay. The results indicate that tidal currents dominate the bay, with significant influences of topographic changes on the velocity and direction of tidal flows. The Eulerian residual current velocity is substantially lower than the tidal current velocity. Both tidal and residual currents play a role in controlling the distribution of materials within Laizhou Bay. Over the past three decades (1990-2023), the tidal prism in Laizhou Bay has shown a downward trend, with the tidal prism during spring, intermediate, and neap tides in 2023 reduced by 2.03%, 6.36%, and 10.19%, respectively, compared to 1990. The water exchange capacity has also weakened, with the half-exchange time being 71 days in 1990, increasing to 73 days in 2003 and 81 days in 2013, and showing a slight increase of 1 day in 2023 compared to 2013. Thus, changes in the coastline and water depth of Laizhou Bay can alter its hydrodynamic conditions, significantly impacting the tidal prism and water exchange, leading to a decrease in tidal prism and exchange rate, an increase in the water exchange period, a slower dispersion rate of pollutants, and a reduced water environmental carrying capacity. This research provides a scientific reference for protecting the marine environment and coastal management in Laizhou Bay.

Valuing community awareness and willingness to pay for marine environment management: empirical analysis in coastal central region of Vietnam

Vietnam is a country with strengths in marine resources and economy. The coast provides habitats and livelihoods for millions of households but is in decline due to economic activity and climate change. This study’s purpose is to evaluate the awareness of people in the central coastal provinces of Vietnam about marine environmental values and their willingness to pay for the management and improvement of marine environmental quality. The study applied a binary random assessment model and surveyed 980 households in 4 coastal provinces to evaluate community payments. The results show that people have good awareness of tangible environmental values, associated with life and livelihood. They also highly agree with protecting marine environmental values and emphasize passing these values on to future generations. Community payment for sea environment management was estimated at 420 thousand/household/year in parametric model and 398 VND thousand/household/year in non-parametric model. Bid level, income and education are main factors affecting people’s ability to pay. The study also proposes implications for marine environmental management including strengthening community awareness and capacity, establishing financial mechanisms for community-led conservation at the local level, and integrating education marine environmental values for high school students to aim for sustainability in community awareness and behavior.

China: 2023 Revision to China’s Marine Environment Protection Law: Interpretations and Implications

Abstract On 24 October 2023, the 6th Session of the Standing Committee of the 14th National People’s Congress published the newly revised Marine Environment Protection Law of the People’s Republic China (“2023 Revised China’s mepl”), which became effective on 1 January 2024. Compared with the previous version, the 2023 Revised China’s mepl mainly involves four changes. Firstly, the 2023 Revised China’s mepl clarifies the legislative purpose and basic principles; secondly, it further strengthens the government’s supervision and control over the marine environment; thirdly, it improves the system design of marine environmental management; fourthly, it incorporates stricter legal liability for violations. It is expected that the 2023 Revised China’s mepl will not only help China address many environmental problems and fulfill its legal obligations under treaties with respect to the marine environment, but also contribute to the advancement of global ocean governance. However, it is crucial to acknowledge that further efforts are necessary to achieve the legislative objectives of the 2023 Revised China’s mepl.

Spatio-temporal dynamics of phytoplankton community structure in the coastal waters of the Southern Beibu Gulf.

This study was conducted during October 2021 (autumn) and April 2022 (spring) to explore the phytoplankton community structure, their distribution characteristics, and the influence of environmental factors in the coastal waters of the Southern Beibu Gulf. The 15 sampling sites were grouped based on the difference in offshore distance to analyze the temporal and spatial differences in community structure and environmental driving in the investigated sea area of the coastal waters of the Southern Beibu Gulf. Permutational multivariate analysis of variance was conducted on the sample data in time and space, revealing that there is no significant difference in space (p > 0.05), but there is significant difference in time (p < 0.05). Notably, water pressure, pH, chemical oxygen demand, nitrite, and labile phosphate were higher in autumn, while total ammonia nitrogen, dissolved oxygen, and suspended solids were significantly higher in spring. Additionally, the study identified 87 phytoplankton species belonging to 6 phyla, dominating by Bacillariophyta, followed by Dinophyta and Cyanophyta. The phytoplankton density, Shannon Weiner's diversity index (H'), Pielou's evenness index (J), and Margalef's richness index (D) ranged from 84.88 to 4675.33 cells L-1, 0.56 to 2.58, 0.26 to 0.89, and 1.21 to 3.64, respectively. Permutational multivariate analysis of variance showed non-significant spatial differences in phytoplankton composition (p > 0.05) but seasonal differences (p < 0.05). Furthermore, canonical correspondence analysis (CCA) identified pH, dissolved oxygen, suspended solids, chemical oxygen demand, nitrite, and labile phosphate as key environmental factors influencing the phytoplankton community structure (p < 0.05). In this study, the dynamic changes of phytoplankton community structure and environmental factors in the southern coastal waters of Beibu Gulf were analyzed in detail from two aspects of time and space. The key environmental factors to protect the ecological environment in the southern coastal area of Beibu Gulf were found out. It provides a reference method and theoretical basis for the management and protection of Beibu Gulf and other tropical marine environment.

DETERMINING SHALLOW WATER BATHYMETRY BY STEREO PHOTOGRAMMETRY TECHNIQUE USING WORLDVIEW-2 IMAGERY

Bathymetry in shallow-water areas plays an important role in marine environment management, marine economic resource development, and national defense and security. The echo sounding method is currently highly accurate; however, it has to deal with a variety of challenges as a result of the high cost, terrain influence, and meteorological conditions at sea. As remote sensing technology progresses, estimating bathymetry using satellite imagery will help lower measuring costs and expand monitoring coverage, particularly in shallow water, offshore areas, and difficult-to-access areas. In this article, the authors present a technique for determining bathymetry in shallow water regions by utilizing WorldView-2 stereoscopic images. The accuracy of stereoscopic depth measurement using WorldView-2 images is assessed by field depth measurement using the single-beam echo sounder. The study area is Nam Yet Island. The coefficient of determination (R2) between the two datasets (field measurement data and using satellite images) is 0.9. The stereoscopic satellite image method of depth measurement is highly accurate for regions with depths below 5 meters. The accuracy of the stereoscopic measurement decreases as the depth increases by more than 5 meters.

A hotspot and mechanism of enhanced bottom intrusion on the southern New England shelf

Understanding the occurrence of the intrusion of open ocean water onto continental shelves has scientific significance and societal relevance as the intrusion can significantly disrupt the marine ecosystem and fisheries. High-resolution numerical modeling is used to investigate the spatiotemporal occurrence and mechanisms of highly anomalous bottom intrusions on the southern New England shelf. Based on multi-year numerical simulations, this study reveals a hotspot of cross-isobath bottom-intensified intrusions at a topographic trough. Examination of multiple events portrays a robust mechanism of locally enhanced bottom intrusions. Persistent upwelling-favorable winds set up an enhanced pressure gradient field at the topographic trough and drive the intrusion a large-distance onshore. Numerical experiments with and without the topographic trough show that the localized pressure gradient results from a combination of the shelf orientation and local bathymetry. Although highly anomalous waters on the shelf relate to wind forcing, correlations between the wind stress anomaly and bottom salinity anomaly at the location of the enhanced intrusion is modest, implying the need to incorporate other environmental factors to develop more deterministic prediction models for subsurface conditions on the shelf. The results have important implications for marine environment and fisheries management.

Integrated assessment of trace elements in a marine ranching area based on multi-species and multi-level biomarkers: a case study in China’s national-level marine ranching demonstration area

The goal of this study was to evaluate the trace element pollution in a marine ranching area in China based on molecular responses (expression of metallothionein and antioxidant enzyme genes), and biochemical biomarkers (metallothionein content, antioxidant enzyme activities, and malonaldehyde level) in four indicator species. We collected samples of two fish (Lateolabrax maculatus and Sebastes schlegelii), one crustacean (Charybdis japonica), and one gastropod (Rapana venosa) from the western Furong Island marine ranching area and from an adjacent area in March 2022 and measured the trace element content in these indicator species as well as in the seawater and sediment. We found that the bioaccumulation characteristics of trace elements and the response patterns of biomarkers were species specific. Moreover, not every biomarker was significantly correlated with environmental trace element content. We then established two biomarker combinations indicative of trace element pollution in seawater and sediment, respectively, based on the correlation between biomarkers and trace element contents. The selected biomarkers were integrated using integrated biomarker response version 2 (IBRv2). IBRv2 values in the studied marine ranching area were lower than those in the adjacent area. Additionally, these values were consistent with the bioaccumulation of trace elements in the indicator species, the integrated trace element pollution index for seawater, and the potential risk index for sediment. These results show that this multi-biomarker and multi-species IBRv2 approach provided a comprehensive diagnosis of trace element pollution in the marine ranching area. Therefore, its application may be beneficial for marine environmental monitoring and management in view of the ecotoxicological impact of pollutants on organisms.

Unveiling the eutrophication crisis: 20 years of nutrient development in Zhanjiang Bay, China

Coastal eutrophication is a major issue of marine pollution. The main factors controlling eutrophication must be identified to ensure effective marine environmental management according to the respective local conditions. Zhanjiang Bay (ZJB), located northwest of the South China Sea, is a semi-closed bay influenced by complex water flows and the development of surrounding cities. In this study, we investigated the development of nutrient concentrations and compositions in ZJB seawater over the past 20 years and the factors influencing eutrophication based on several field investigations from 2006 to 2022 and historical data. High concentrations of dissolved inorganic phosphorus (DIP) and dissolved inorganic nitrogen (DIN) were the main contributors to the severe long-term eutrophication in ZJB; however, light eutrophication was observed in the outer bay, primarily caused by chemical oxygen demand (COD) and DIP. The primary sources of COD and nutrients were riverine freshwater, sewage outfalls, mariculture and domestic effluents carried by rivers. Tidal effects diluted the nutrient concentrations in the bay with seawater from the outer bay, thereby playing a key role in nutrient redistribution. The DIN: DIP ratio of ZJB showed long-term nitrogen restriction and excess phosphorus, primarily owing to mariculture activities. Marine undertakings can exert various impacts on water quality. Eliminating illegal aquaculture and launching aquaculture tailwater treatment can improve water quality, whereas practices such as channel dredging may worsen it. This study demonstrates the intricate dynamics of the ZJB ecosystem and offers valuable insights for effective environmental management and conservation efforts.

Fluorescent labelling combined with confocal differential Raman spectroscopy to detect microplastics in seawater

As an emerging marine pollutant, microplastics represent a focal point in global monitoring and management efforts. With seawater accounts for 97 % of the total global water resources, scientific assessments of microplastics in seawater are crucial for pollution control and management of marine environments. This study focuses on investigating microplastics in near-shore seawater and proposes a rapid and accurate detection method using a constructed confocal Raman spectroscopy detection system. By optimizing the pretreatment process of seawater microplastic samples, the efficient removal of organic matter interference in microplastic detection is achieved. Employing fluorescent labeling addresses the issues of prolonged detection time and high false positive rates associated with traditional methods, enabling rapid differentiation between microplastics and other substances and significantly enhancing detection efficiency and accuracy. Additionally, the use of differential Raman spectroscopy effectively mitigates fluorescence signal interference, thus improving the signal-to-noise ratio of the spectra. By employing dual-wavelength laser excitation at 784 nm/785 nm, microplastics such as polyethylene (PE), polypropylene (PP), polystyrene (PS) ranging in size from 60 to 500 μm are successfully detected in seawater. The results demonstrate that the proposed pretreatment method for seawater microplastics and novel detection techniques enable rapid screening and comprehensive non-destructive detection of microplastics in seawater, thereby facilitating the characterization of marine microplastics and providing scientific support for enhancing the management of microplastic pollution and ecological risk control.

ECR Spotlight – Emma Strand

ECR Spotlight is a series of interviews with early-career authors from a selection of papers published in Journal of Experimental Biology and aims to promote not only the diversity of early-career researchers (ECRs) working in experimental biology but also the huge variety of animals and physiological systems that are essential for the ‘comparative’ approach. Emma Strand is an author on ‘ Coral species-specific loss and physiological legacy effects are elicited by an extended marine heatwave’, published in JEB. Emma conducted the research described in this article while a PhD candidate in Dr Hollie Putnam's lab at University of Rhode Island, Kingston, USA. She is now a postdoctoral scientist in the lab of Tim O'Donnell at Gloucester Marine Genomics Institute, Gloucester, MA, USA, investigating sustainable fisheries and aquaculture, focused on developing genomic tools to advance research-based sustainable management of marine environments, and climate change resilience, focused on investigating how marine organisms respond to rapidly changing environments.

Predictive mapping of organic carbon stocks in surficial sediments of the Canadian continental margin

Abstract. Quantification and mapping of surficial seabed sediment organic carbon have wide-scale relevance for marine ecology, geology and environmental resource management, with carbon densities and accumulation rates being a major indicator of geological history, ecological function and ecosystem service provisioning, including the potential to contribute to nature-based climate change mitigation. While global analyses can appear to provide a definitive understanding of the spatial distribution of sediment carbon, regional maps may be constructed at finer resolutions and can utilise targeted data syntheses and refined spatial data products and therefore have the potential to improve these estimates. Here, we report a national systematic review of data on organic carbon content in seabed sediments across Canada and combine this with a synthesis and unification of the best available data on sediment composition, seafloor morphology, hydrology, chemistry and geographic settings within a machine learning mapping framework. Predictive quantitative maps of mud content, dry bulk density, organic carbon content and organic carbon density were produced along with cell-specific estimates of their uncertainty at 200 m resolution across 4 489 235 km2 of the Canadian continental margin (92.6 % of the seafloor area above 2500 m) (https://doi.org/10.5683/SP3/ICHVVA, Epstein et al., 2024). Fine-scale variation in carbon stocks was identified across the Canadian continental margin, particularly in the Pacific Ocean and Atlantic Ocean regions. Overall, we estimate the standing stock of organic carbon in the top 30 cm of surficial seabed sediments across the Canadian shelf and slope to be 10.9 Gt (7.0–16.0 Gt). Increased empirical sediment data collection and higher precision in spatial environmental data layers could significantly reduce uncertainty and increase accuracy in these products over time.

A Comparison of new and age-old approaches treating microplastics in the marine environment

In recent years, microplastic pollution in the ocean has become a new environmental threat, posing a serious potential threat to marine ecology. Due to its high degradation resistance and bioaccumulation, it is an urgent and critical issue for the environment. Unfortunately, current technologies for removing, recycling, or degrading microplastics are not sufficient to eliminate them. The main sources of microplastics (MPs) in the ocean are ocean drift inputs, river inputs, fishing and shipping activities, microplastic emissions from human settlements, and atmospheric migration. Microplastics may pose a threat to marine life and affect the stability of marine ecosystems. Therefore, it is urgent to further study governance methods and analysis processes, and strengthen the source control of marine microplastic pollution. This study aims to analyze and discuss different methods for treating marine microplastics, analyze their respective advantages and limitations, and evaluate their feasibility and effectiveness in practical applications. The study ultimately emphasized the importance of effective management of marine microplastics, which is crucial for protecting marine ecosystems and human health. Through a comprehensive analysis of physical, chemical, and biological methods, this study provides valuable insights for marine environmental management and research institutions, thereby promoting the development and application of effective management technologies to achieve sustainable environmental outcomes.

An empirical study of marine environmental civil public-interest litigation in China: Based on 216 cases from 2015 through 2022

This article examines marine environmental civil public-interest litigation landscape in China based on a comprehensive empirical study of 216 cases adjudicated from 2015 through 2022. Marine environmental civil public-interest litigation is under robust development in China with the number of cases increasing and high-profile cases emerging. Many cases were built upon related criminal and administrative proceedings and the procuratorate, as a qualified plaintiff, has led in initiating litigation. The liability system is maturing with flexible remedies and a high plaintiff win rate. First-instance judgments were rendered effectively and alternative dispute resolution was used. Besides the notable progress deserving attention, there are still several obstacles yet to be overcome, such as the divergence in the categorization of cases, the application of law and the attitude towards the standing of environmental NGOs. Besides, the number of cases initiated by marine environmental supervision and management departments is relatively small and jurisdictional matters also need to be further clarified. A feasible approach to overcome these obstacles is to come up with a set of systematic and coordinated rules in this field either by releasing specialized judicial interpretations on marine environmental public-interest litigation or by revising the existing Marine Environmental Protection Law when appropriate. By this means, it could potentially optimize the system of marine environmental civil public-interest litigation and enhance its efficacy in protecting the marine environment and resources.

Using the Heavy Metal and Biotic Indices to Assess Ecological Quality in the Central Area of the East Sea, South Korea

With the rapid development of the South Korean economy, human activities have extensively affected Korea’s coastal environment. A precise ecological quality assessment remains paramount despite the relatively lower impact of human activities on the East Sea compared to the West and South Seas of South Korea. Accurate ecological quality assessments can provide valuable marine environmental protection and management references. In our study, we employed seven indices based on heavy metals and macrobenthos to comprehensively assess ecological quality. Our results indicated the final ecological quality in the central East Sea of South Korea was acceptable at most stations; however, the ecological quality in winter marginally falls short compared to that in spring. The concentration of heavy metals emerges as a significant determinant of the final ecological quality, underscoring the need for subsequent studies to investigate the origins of heavy metals in the central East Sea of South Korea and the influence of anthropogenic activities on heavy metal concentrations. Furthermore, employing a single biotic index proves challenging for accurately assessing ecological quality in the East Sea of South Korea.

An insight into the Application of AI in maritime and Logistics toward Sustainable Transportation

This review article looks at the developing field of artificial intelligence and machine learning in maritime and marine environment management. The marine industry is increasingly interested in applying advanced AI and ML technologies to solve sustainability, efficiency, and regulatory compliance issues. This paper examines maritime and marine AI and ML applications using a deep literature review and case study analysis. Modeling ship fuel consumption, which impacts the environment and operating expenses, is a top responsibility. The study demonstrates that ML approaches such as Random Forest and Tweedie models can estimate ship fuel use. Statistical analysis demonstrates that the Random Forest model beats the Tweedie model regarding accuracy and consistency. For the training and testing datasets, the Random Forest model has high R2 values of 0.9997 and 0.9926, indicating a solid match. Low Root Mean Square Error (RMSE) and average absolute relative deviation (AARD) suggest that the model accurately reflects fuel use variability. While still performing well, the Tweedie model has lower R2 values and higher RMSE and AARD values, suggesting reduced accuracy and precision in fuel consumption prediction. These findings provide light on the potential applications of artificial intelligence and machine learning in maritime and marine environment management. Advanced analytics enables decision-makers to analyze fuel consumption patterns better, increase operational efficiency, and decrease environmental impact, thus improving maritime sustainability.

Importance of integrating mixoplankton into marine ecosystem policy and management-Examples from the Marine Strategy Framework Directive.

Marine plankton capable of photosynthesis and predation ("mixoplankton") comprise up to 50% of protist plankton and include many harmful species. However, marine environmental management policies, including the European Union Marine Strategy Framework Directive (MSFD) and the USEPA, assume a strict dichotomy between autotrophic phytoplankton and heterotrophic zooplankton. Mixoplankton often differ significantly from these two categories in their response to environmental pressures and affect the marine environment in ways we are only beginning to understand. While the management policies may conceptually provide scope for incorporating mixoplankton, such action is rarely implemented. We suggest that the effectiveness of monitoring and management programs could benefit from explicit implementations regarding the ecological roles and impact of mixoplankton. Taking the MSFD as an example of marine management guidelines, we propose appropriate methods to explicitly include mixoplankton in monitoring and marine management. Integr Environ Assess Manag 2024;20:1366-1383. © 2024 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Biosensors for ocean acidification detection

Ocean acidification is a global environmental problem that significantly impacts Marine ecosystems and biodiversity. The traditional chemical analysis method has the problems of complex equipment and high cost in ocean acidification monitoring. In recent years, fluorescent protein biosensor technology, as an innovative monitoring method, has provided a new solution for the real-time detection of ocean acidification. Compared with traditional chemical analysis methods, fluorescent protein biosensors have the advantages of simple operation, high sensitivity and low cost. Current studies have demonstrated the potential of fluorescent protein biosensors for ocean acidification monitoring. The researchers designed a variety of fluorescent protein biosensors and conducted indoor and outdoor experimental validation. These results show that fluorescent protein biosensors can detect ocean acidification quickly and accurately and maintain stable performance under different environmental conditions. Further studies are needed to verify the consistency and reliability of fluorescent protein biosensors and traditional chemical analysis methods for ocean acidification monitoring. Future research directions include further improving the performance of the fluorescent protein biosensor, increasing its sensitivity and stability, and verifying its application in real Marine environments. This will help establish a better monitoring network for ocean acidification and provide a reliable scientific basis for Marine environmental protection and management decisions. The development and application of fluorescent protein biosensor technology will provide important support and guidance for us to better understand the impact of ocean acidification.

Assessing the Benthic Ecological Quality in the Intertidal Zone of Cheonsu Bay, Korea, Using Multiple Biotic Indices

With the growing global focus on marine environmental conservation and management, it is imperative to evaluate the ecological quality of marine ecosystems accurately. In this study, we employed seven biotic indices, namely the AZTI marine biotic index (AMBI), BENTIX, benthic opportunistic polychaetes amphipods index (BOPA), benthic pollution index (BPI), multivariate AZTI marine biotic index (M-AMBI), abundance biomass comparison (W-value), and Shannon diversity index (H’), to assess the benthic ecological quality in the intertidal zone of Cheonsu Bay, South Korea. Except for the H’ and W-value, the indices (AMBI, BENTIX, BOPA, BPI, and M-AMBI) suggest that the ecological quality at most stations in the intertidal zone of Cheonsu Bay was acceptable. Furthermore, the influx of a large amount of eutrophic freshwater has impacted the intertidal zone of Cheonsu Bay, but the applicability of the seven biotic indices requires further investigation.