Zacco Platypus Research Articles

Microplastic characterization in small freshwater fishes collected in Gyeongan-cheon, a tributary stream of Han River in South Korea: Ingestion and depuration study of Nylon

Plastic inventions have had an impact on various industries, and people easily approach to plastic products, degrading into microplastic (MP). In this study, distribution of MP was evaluated in freshwater fishes collected in a tributary stream of the Han River, Gyeongan-cheon. Totally 38 fishes, mostly Zacco platypus, were used to analyze, and they were collected in two different seasons as the normal and rainy seasons. Fishes contained 34–284 particles/individual. The prevalent size of MP in fishes ranged from 45 to 100 μm, followed by 100–300 and 20–45 μm. Shapes of MP in fishes were mostly fragments, and types of MP were polypropylene (PP) > polyethylene (PE) > polytetrafluoroethylene (PTFE). By 4-day ingestion of Nylon at 100 μg/L (equivalent to 55,000 particles/L, about 20–40 μm) in Zacco koreanus, the treated fish showed MP concentration with an average number of 53 Nylons. Mean retention time value was considered as 13.4 days by the uptake-depuration test using Z. platypus at 500 μg/L Nylon. Taken together, MP concentration found in smaller freshwater fish was dependent on living habitat and MP size. These findings underscore the importance of ongoing monitoring of MPs in freshwater ecosystems and the need to understand MP ingestion and excretion patterns in small freshwater fish species.

Assessing and Optimizing Ecological Flow Rates for the Habitat of Zacco platypus in the Tan River

As rivers face growing environmental challenges due to climate change and the construction of artificial structures, it is essential that we improve river ecosystems to maintain their ecological functions and preserve the health of aquatic habitats. The aim of this study was to assess the aquatic ecosystem health of the lower reaches of the Tan River. We employed the Physical Habitat Simulation System and Hydrologic Engineering Center’s River Analysis System to calculate the ecological flow rate based on the weighted usable area (WUA) of Zacco platypus, which is a representative fish species in the Tan River, and the flow rate relationship curves. By analyzing the flow rates in the Tan River across different seasons from 2012 to 2021, we determined that the seasonal optimal ecological flow rate was 10.21–10.27 m3/s. Meanwhile, the WUAs for spring, summer, and autumn and winter were 90–100%, 95–100%, and 75–100%, respectively. Despite meeting the ecological flow criteria for summer, fall, and winter over 50% of the time, spring fell short at 41%; hence, the Tan River flow rates should be secured particularly in spring. This study highlights the urgency of addressing seasonal variations to ensure the overall health of the Tan River ecosystem.

Annotation and Characterization of the Zacco platypus Genome

The pale chub Zacco platypus (Cypriniformes; Xenocyprididae; Jordan & Evermann, 1902) is widely distributed across freshwater ecosystems in East Asia and has been recognized as a potential model fish species for ecotoxicology and environmental monitoring. Here, a high-quality de novo genome assembly of Z. platypus was constructed through the integration of a combination of long-read Pacific Bioscience (PacBio) sequencing, short-read Illumina sequencing, and Hi-C sequencing technologies. Z. platypus has the smallest genome size compared to other species belonging to the order Cypriniformes. The assembled genome encompasses 41.45% repeat sequences. As shown in other fish, a positive correlation was observed between genome size and the composition of transposable elements (TE) in the genome. Among TEs, a relatively higher rate of DNA transposon was observed, which is a common pattern in the members of the order Cypriniformes. Functional annotation was processed using four representative databases, identifying a core set of 12,907 genes shared among them. Orthologous gene family analysis revealed that Z. platypus has experienced more gene family contraction rather than expansion compared to other Cypriniformes species. Among the uniquely expanded gene families in Z. platypus, detoxification and stress-related gene families were identified, suggesting that this species could represent a promising model for ecotoxicology and environmental monitoring. Taken together, the Z. platypus genome assembly will provide valuable data for omics-based health assessments in aquatic ecosystems, offering further insights into the environmental and ecological facets within this species.

Evaluation of fish habitat suitability based on stream hydrodynamics and water quality using SWAT and HEC-RAS linked simulation

The objective of this study was to evaluate fish habitat suitability by simulating hydrodynamic and water quality factors using SWAT and HEC-RAS linked simulation considering time-series analysis. A 2.9 km reach of the Bokha stream was selected for the habitat evaluation of Zacco platypus, with hydrodynamic and water quality simulations performed using the SWAT and HEC-RAS linked approach. Based on simulated 10-year data, the aquatic habitat was assessed using the weighted usable area (WUA), and minimum ecological streamflow was proposed from continuous above threshold (CAT) analysis. High water temperature was identified as the most influential habitat indicator, with its impact being particularly pronounced in shallow streamflow areas during hot summer seasons. The time-series analysis identified a 28% threshold of WUA/WUAmax, equivalent to a streamflow of 0.48 m3/s, as the minimum ecological streamflow necessary to mitigate the impact of rising water temperatures. The proposed habitat modeling method, linking watershed-stream models, could serve as a useful tool for ecological stream management.

A chromosome-level genome assembly of East Asia endemic minnow Zacco platypus

Zacco platypus is an endemic colorful freshwater minnow that is intensively distributed in East Asia. In this study, two adult female individuals collected from Haihe River basin were used for karyotypic study and genome sequencing, respectively. The karyotype formula of Z. platypus is 2N = 48 = 18 M + 24SM/ST + 6 T. We used PacBio long-read sequencing and Hi-C technology to assemble a chromosome-level genome of Z. platypus. As a result, an 814.87 Mb genome was assembled with the PacBio long reads. Subsequently, 98.64% assembled sequences were anchored into 24 chromosomes based on the Hi-C data. The chromosome-level assembly contained 54 scaffolds with a N50 length of 32.32 Mb. Repeat elements accounted for 52.35% in genome, and 24,779 protein-coding genes were predicted, with 92.11% were functionally annotated with the public databases. BUSCO analysis yielded a completeness score of 96.5%. This high-quality genome assembly provides valuable resources for future functional genomic research, comparative genomics, and evolutionary studies of genus Zacco.

Spatiotemporal Variation Analyses of Water Quality, Fish Ecological Guilds, and the Longitudinal Connectivity in Musim Stream

The main objectives of this study were to analyze the spatiotemporal variations of water quality, fish ecological guilds and longitudinal connectivity in the weirs of Musim Stream. Fish were collected at 44 sites during spring and fall seasons for the analysis of trophic guilds, tolerance guilds, and the ecological stream health, based on FAI model. Total 33 species were observed in the stream and the dominant species were <i>Zacco platypus</i> and <i>Squalidus qracilis majimae</i>. Mean values of BOD and COD, as an indicator of organic matter pollution, showed high in the drought spring and low in fall (post-monsoon season). Also, TP showed same pattern with the BOD and COD pattern. The hierarchical clustering, based on the fish compositions, classified as three groups (up-stream, mid-stream and the down-stream). Based on the NMDS (Non-metric Multidimensional Scaling) analysis of fish abundance, high similarity was observed between S1-S5 sites, which were consistent with the results of hierarchical cluster analysis. Fish ecological guilds in the upper stream showed a high similarity between the insectivore and sensitive species, while in the middle and lower reaches, high similarity was found between the omnivore and intermediate species. Evaluations of longitudinal connectivity, based on the structural and hydrological characteristics of the weir, indicated all disconnections by the weirs, except for S15, in the spring. Stream ecological health, based on the FAI model, was significantly (<i>p</i> < 0.05, n=37) influenced by the height of overflow (<i>Hu1</i>). Overall, our study suggests that the longitudinal connectivity, based on the weir structures, flow regime and fish swimming capacity, were blocked off by the weirs in the stream. The results provide valuable insights for securing river management strategies and served as the fundamental data for stream restoration in the future.

Redescriptions of Illiosentis ctenorhynchus Cable & Linderoth, 1963 (Illiosentidae) and Micracanthorhynchina motomurai (Harada, 1935) (Rhadinorhynchidae: Gorgorhynchinae) (Acanthocephala: Palaeacanthocephala)

We provide redescriptions of two species of acanthocephalans in one class Palaeacanthocephala and 2 families collected from hosts in different geographical locations in Jamaica and Korea. Each species account is annotated and morphologically presented using light microscopy showing new characteristic diagnostic features. In Illiosentidae, we provide a new description of Illiosentis ctenorhynchus Cable & Linderoth, 1963 from the type host, the yellow goatfish Mulloidichthis martinicus (Cuvier) in Jamaica that completes and corrects the inadequate and incomplete original description. In Rhadinorhynchidae (Rhadinorhynchinae), we redescribe Micracanthorhynchina motomurai (Harada, 1935) from the pale chub Zacco platypus (Temminck & Schlegel) and the dark chub Zacco temmincki (Temminck & Schlegel) in Korea and complement much missing information and images. We also provide museum numbers for lectotype male, allolectope female, and paralectotypes that we have deposited as Harada did not designate type material for M. motomurai.

Ecological connectivity analysis based on the fish community in Jeongan Stream

This study focused on the longitudinal connectivity analysis, based on fish communities in the aspect of spatial variations of 34 sites from upstream to downstream. The Fish Assessment Index (FAI), based on ecological guilds and species composition, was applied to compare the ecological health among the sampling sites. The total number of 35 fish species, were sampled during the study period with dominant species of <i>Zacco platypus</i> (35.4%) and <i>Zacco koreanus</i> (11.8%). Cluster analysis showed that all sites were categorized as 4 distinct group communities (A, B, C, D). Non-metric multidimensional scaling analysis showed distinct difference between upstream (A, B) and downstream groups (C, D). Indicator Value Analysis (IndVal method), conducted to identify indicator species within each group, indicated that the species favoring upstream environments Rhynchocypris oxycephalus for the Group A and Iksookimia koreensis for the Group B. In contrast, the analysis indicated that the species with a preference for downstream habitats Pseudogobio esocinus for the Group C and Carassius auratus for the Group D. Ecological health, based on the FAI scores, showed a declining pattern toward the downstream, along with an increasing proportion of tolerant species and omnivores within the fish community. Overall these findings suggest the compositions of fish communities, as four groups, were modified by the weir structures and organic matter, nutrient pollutions.

Proposing Effective Ecotoxicity Test Species for Chemical Safety Assessment in East Asia: A Review.

East Asia leads the global chemical industry, but environmental chemical risk in these countries is an emerging concern. Despite this, only a few native species that are representative of East Asian environments are listed as test species in international guidelines compared with those native to Europe and America. This review suggests that Zacco platypus, Misgurnus anguillicaudatus, Hydrilla verticillata, Neocaridina denticulata spp., and Scenedesmus obliquus, all resident to East Asia, are promising test species for ecotoxicity tests. The utility of these five species in environmental risk assessment (ERA) varies depending on their individual traits and the state of ecotoxicity research, indicating a need for different applications of each species according to ERA objectives. Furthermore, the traits of these five species can complement each other when assessing chemical effects under diverse exposure scenarios, suggesting they can form a versatile battery for ERA. This review also analyzes recent trends in ecotoxicity studies and proposes emerging research issues, such as the application of alternative test methods, comparative studies using model species, the identification of specific markers for test species, and performance of toxicity tests under environmentally relevant conditions. The information provided on the utility of the five species and alternative issues in toxicity tests could assist in selecting test species suited to study objectives for more effective ERA.

Evaluating the Longitudinal Connectivity of Dorim Stream in Seoul based on Artificial Constructure and Fish Data

The vertical connectivity of the river aquatic ecosystem was evaluated based on fish and artificial structures in Dorim stream, an urban stream in Seoul. As a result of a survey in the downstream area in 100.0 m of a total of 71 artificial structures, 13,728 individuals of fishes belonging to five orders, seven families, and 25 species were investigated, with the dominant species Zacco platypus and the subdominant species Rhynchocypris oxycephalus. As for endemic species, seven species were investigated and in terms of feeding characteristics, omnivorous species were the most common with 17 species (68%). Also an alien species, Poecilia reticulata was found. Fish species tended to decrease as the survey was conducted to upstream. Based on the movement characteristics of the fish species and the features of artificial structure survey results, the longitudinal continuity of each artificial structure was evaluated as 43 continuity, two damaged, 19 discontinuity, and seven absent. In inclined structures, stream velocity was found to be the main factor for discontinuity. In vertical structures, the down depth and head drop appeared to be the main factors for discontinuity. The results of this survey are expected to serve as basic data for the conservation of river aquatic ecosystems in the future.

Evaluation and securing of ecological flow by linking fish growth scenarios and basin water budget analysis

Maintaining ecological flow is crucial for preserving healthy aquatic ecosystems. This study presents a novel approach to assess and secure ecological flow by linking fish growth scenarios with water budget analysis. Addressing the challenges of accurately predicting ecological flow requirements, especially in post-dam-construction scenarios, is a central focus. In the Gam River basin, we assess the compatibility of a target fish species with post-dam quantitative instream flow, confirming an appropriate 4 m3/s for Zacco platypus in the basin's water supply system. This determination, facilitated by the K-WEAP model, not only ensures water availability but also prevents the Gimcheon-Buhang Dam from falling below its dead storage water level. Our study's key achievements include the development and successful application of this innovative methodology, integrating basin water budget analysis with fish population growth predictions across varying flow conditions. This approach allows the identification of potential ecosystem risks like water scarcity or pollution and determines the optimal ecological flow needed for maintaining the river ecosystem. Our research provides valuable insights for future endeavors in sustainable water resources management and river ecosystem conservation efforts.

Length-Weight Relationships for Ten Fish Species from Rivers in the Qinling Mountains, China

Length-weight relationships (LWRs) were reported for ten fish species (Abbottina rivularis, Hemibarbus labeo, Hemibarbus maculatus, Onychostoma macrolepis, Opsariichthys bidens, Rhynchocypris lagowskii, Schizothorax prenanti, Sinibrama macrops, Zacco platypus, and Siniperca scherzeri). Fishes were collected from 62 sampling stations covering an area of ∼7000 km2 in the Qinling Mountains, characterized by unique fauna and distribution pattern, using gillnets and ground cages during June to December 2022. The intercept a ranged from 0.013 for S. prenanti to 0.060 for H. labeo, and the slope b ranged from 2.537 for H. labeo to 3.079 for Z. platypus.

Longitudinal Connectivity Evaluations along with Chemical Water Quality and Biological Integrity analyses Based on Fish Multi-metric Model in Tan Stream

The main objectives of this study were to evaluate biological integrity analysis and longitudinal connectivity assessment in Tan Stream. The research included the analysis of chemical water quality, ecological health assessment based on fish, and a comparison of aquatic ecosystem health before and after restoration, following the removal of two weirs (Baekgung weir and Baekhyeon weir) among the nine weirs with five fishways. Additionally, an assessment of longitudinal connectivity is being conducted. Dissolved oxygen (DO), biological oxygen demand (BOD), total organic carbon (TOC), total nitrogen (TN), total phosphorus (TP), and suspended solids (SS) concentrations were not high based on the criteria of the Ministry of Environment, Korea. The ecological health assessment based on fish showed an average health grade of “Fair (C)”, indicating a partial deterioration of ecological health, with <i>Zacco platypus</i> as the dominant species. The results of the regression analysis showed that there was no significant correlation between water quality and ecological health (<i>p</i> > 0.05). After the removal of Baekgung weir, the health of the aquatic ecosystem (FAI) improved slightly, increasing from “50” to “56.25”. And after the removal of Baekhyeon weir, the value remained the same as before the removal (“56.25”). However, it was found that the overall improvement effect on the entire Tan Stream was minimal. The evaluation of longitudinal connectivity revealed, three continuities, two partial continuities and two discontinuities at the artificial weir unit level, while at the stream unit level, it was evaluated as “continuous (52.8%)”. Further comprehensive research is needed to investigate the potential impact of artificial structures on the integrity of the aquatic ecosystem.

Body distribution and ecotoxicological effect of nanoplastics in freshwater fish, Zacco platypus

The increased consumption of plastics worldwide, has led to the emergence of nanoplastics as important environmental pollutants. Despite the presence of nanoplastics in aquatic environments, their effects on ecosystems remain largely unexplored due to the analysis complexity. This study investigated the organ accumulation and toxic effects of 50 nm polystyrene nanoplastics (PS-NPs) in Zacco platypus (Z. platypus; also known as pale chub fish) using pyrolyzer-gas chromatography-mass spectrometry (Pyr-GC/MS). PS-NPs accumulated in Z. platypus’ brain, digestive tract, branchia, and liver, causing changes at cellular level. Over a 14-day exposure, the accumulated PS-NPs led to observable changes in fish behavior (e.g., Total traveled distance and maximum velocity). In addition, the oxidative stress in each organ of Z. platypus increased as the exposure concentration of PS-NPs increased. This study shows that accumulation of nanoplastics in fish, resulting in behavioral changes and biochemical toxicity. As the pattern of change magnifies with exposure time and concentration, from a long-term perspective, the influence of nanoplastics on aquatic ecosystems become evident. This underscores the urgency for continuous research into the potential risks of nanoplastics in aquatic ecosystems.

Assessing the Impact of Human-Induced and Climate Change-Driven Streamflow Alterations on Freshwater Ecosystems

Streamflow is critical and master variable for maintaining healthy and restorative processes in freshwater ecosystems. However, human-induced dam construction and climate change have significantly altered the flow regime and disrupted hydrological conditions. Consequently, protecting river ecosystems has become a crucial goal, necessitating environmental streamflow assessments. This study evaluates the impact of dam construction and climate change on the flow regime and environmental flow in the Gamcheon Basin, Korea. It focuses on two fish species, the dominant Zacco platypus and endangered Squalidus gracilis majimae, using an ecosystem function model to determine the appropriate environmental flow. GIS analysis was also employed to quantify the habitat connectivity within the assessed environmental streamflow. The study provides key insights into preserving streamflow and revitalizing river ecosystems, highlighting the need for a broader multi-species analysis for environmental flow determination and conservation. By determining the appropriate environmental flow and analyzing habitat connectivity, effective strategies can be developed for protecting and maintaining healthy freshwater ecosystems in a changing climate.

Estimation of least ecological streamflow through long-term habitat evaluation using stream hydrodynamics and water quality factors

ABSTRACT The objectives of this study were to evaluate aquatic habitat suitability considering stream hydraulics as well as water quality and to propose a stream ecological flow rate for Zacco platypus in the Banbyeon Stream of South Korea. Stream water temperature and dissolved oxygen (DO) in addition to streamflow velocity and depth were simulated using the Hydrologic Engineering Center-River Analysis System (HEC-RAS) from 2010 to 2020 and then used to estimate weighted usable area (WUA) as the proxy indicator of stream habitat suitability. The continuous above-threshold (CAT) analysis revealed several anomalous drops in WUA as the combined effect of water temperature rise and streamflow reduction. A WUA/WUAmax ratio of about 24% seems to be a threshold level below which water temperature rises more rapidly as streamflow decreases. This is equivalent to a streamflow rate of 3.6 m3/s and is proposed as the least ecological streamflow to sustain minimal aquatic habitat suitability.

Transcriptome and computational approaches highlighting the molecular regulation of Zacco platypus induced by mesocosm exposure to common disinfectant chlorine

Chlorine (Cl2) is a disinfectant often used in swimming pools and water treatment facilities. However, it is released into aquatic ecosystems, where it may harm non-targeted organisms. Here, we performed a mesocosm experiment exposing Zacco platypus (Z. platypus) to biocide Cl2 for 30 days (30 d) at two days' time points 15 days (15 d) and 30 d samples were collected. Here, Z. platypus was exposed to a sublethal concentration (0.1 mg/L) of Cl2, and comparative transcriptomics analyses were performed to determine their response mechanisms at the molecular level. According to RNA sequencing of the whole-body transcriptome, 860 and 1189 differentially expressed genes (DEGs) were identified from the 15 d and 30 d responses to Cl2, respectively. After enrichment analysis of GO (Gene Ontology) functions and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways, identified DEGs were demonstrated to be associated with a variety of functions, including “ion binding and transmembrane transporters”. Cl2 also induced oxidative stress in Z. platypus by increasing the levels of reactive oxygen species (ROS) while decreasing the catalase (CAT) content and the levels of solute carrier family 22 member 11 (slc22a11), Caspase-8 (casp-8), inducible nitric oxide synthase (NOS2), cytosolic phospholipase A2 gamma (PLA2G4). However, Z. platypus still allows recovery during stress suspension by increasing the expression levels of solute carrier family proteins. The GO and KEGG annotation results revealed that the expression of DEGs were related to the detoxification process, immune response, and antioxidant mechanism. Additionally, protein-protein interaction networks (PPI) and cytoHubba analyses identified sixteen hub genes and their interaction. These findings elucidate the regulation of various DEGs and signaling pathways in response to Cl2 exposure, which will improve our knowledge and laid foundation for further investigation of the toxicity of Cl2 to Z. platypus.

Assessment of Aquatic Ecological Health Based on the Characteristics of the Fish Community Structures of the Hun River Basin, Northeastern China

Long-term ecological restoration can restore aquatic ecosystems to a certain extent and alleviate the crisis of freshwater fish biodiversity. In order to explore the fish community distribution patterns and key factors after ecological restoration and the health status of the watershed, fish and environmental data were collected from 39 sampling points in the Hun River Basin in the spring and autumn of 2021. A total of 51 fish species belonging to 11 families and 37 genera were collected during the survey, and the dominant species were Rhynchocypris lagowskii, Zacco platypus, Carassius auratus and Pseudorasbora parva. Compared with the results of past studies, the number of fish species has increased. The study found that the distribution of fish along the longitudinal gradient of the watershed showed obvious spatial differences and was divided into two groups. The results of canonical correspondence analysis (CCA) showed that agricultural land, urban land and grassland were the key factors for the spatial variation in fish communities in the Hun River Basin. The results of the F-IBI evaluation showed that the health status of the Hun River was fair or above fair, among which healthy, good, fair, poor and bad points accounted for 5.13%, 30.77%, 33.33%, 25.64% and 5.13%, respectively. The upper and middle reaches of the Hun River Basin were in better health, while the lower reaches were in poorer health, which was mainly affected by the intensity of human activities in different regions. This study will help watershed managers to make targeted restoration and protection measures for different regions.

계룡산국립공원의 어류군집 특성 및 하천건강성 평가

This study investigated the characteristics of fish communities and river health in the Gyeryeongsan National Park, Korea from May to September 2021. The survey collected 26 species belonging to nine families from 22 survey stations. The dominant and subdominant species were Zacco platypus(26.4%) and Rhynchocypris oxycephalus(26.1%), respectively. The next most abundant species were Zacco koreanus(21.1%), Squalidus gracilis majimae(11.0%), Pungtungia herzi(3.4%), Iksookimia koreensis(2.6%) and Rhinogobius brunneus (2.5%). Among the fish species collected, 12(46.2%) were Korea endemic species, including Rhodeus uyekii, Acheilognathus koreensis, Squalidus gracilis majimae, Microphysogobio yaluensis, Zacco koreanus, Iksookimia koreensis, Pseudobagrus koreanus, Silurus microdorsalis, Liobagrus mediadiposalis, Coreoperca herzi, Odontobutis platycephala and Odontobutis interrupta. Additionally, one exotic species(ecosystem-disturbing species Micropterus salmoides) and one landlocked species (Rhinogobius brunneus) were collected. As a result of community indices, the dominance(0.67~1.00), diversity(0.136~1.658), evenness(0.123~1.988), and richness(0.201~2.031) differed significantly by stations. Also, river health(index of biological integrity) was assessed as very good(seven stations) and good(15 stations). Gyeryeongsan National Park had a relatively well-preserved river ecosystem, but several disturbance factors(weir was installed at nine stations, river work was underway at five stations, and ecological disturbance species, M. salmoides were introduced into the Yongdong Reservoir area. The stable populations of fish in Gyeryongsan National Park require a river ecosystem protection plan and a systematic management plan for ecological disturbance species, M. salmoides.

Fish Diversity and Ichthyofauna of Areas Adjacent to the Demilitarized Zone in South Korea

The Korean Demilitarized Zone (DMZ) was established in 1953 during the cessation of the Korean War, which divided the Korean Peninsula into North and South Korea. The DMZ is a representative biodiversity resource because it limits human activities. The current status of faunal diversity in adjacent areas of the DMZ was investigated in five regions at 91 sites from 2015 to 2019. A total of 19,562 individuals were collected and identified, including 81 species, 19 families, and 11 orders. Zacco koreanus was the most abundant fish species (relative abundance of 21.9%), while other key species were Zacco platypus (18.2%), Rhynchocypris oxycephalus (5.2%), Rhynchocypris steindachneri (4.9%), and Pungtungia herzi (3.7%). Notably, twenty-nige endemic and seven Red Data Book species were recorded, and three exotic species, Carassius cuvieri, Micropterus salmoides, and Lepomis macrochirus were found at five sites. Human activities and disturbances were found at 34.0% of all sampling sites, and the highest disturbance factors were river dredging and agricultural use (seven sites), sewage (five sites), and fisheries and development (two sites). We recommend that the governments of South and North Korea collaboratively manage the DMZ to protect ecological diversity and maintain its status as a symbol of peace.