Publications
A Novel Discovery of Microorganisms Associated with Certain Seaweed Species from the Cat Ba Archipelago Area, Vietnam: Isolation, Identification and Exploration of Their Antimicrobial Activities
A novel discovery of microorganisms associated with seaweed species from the Cat Ba Archipelago, Vietnam, reveals promising antimicrobial activities. Researchers isolated 331 culturable microorganisms from nine marine macroalgal hosts, identifying 15 bacterial isolates—predominantly Bacillus species—with significant antibacterial properties. Notably, Bacillus velezensis S.002, associated with the red alga Gelidium crinale for the first time, exhibited remarkable activity against B. subtilis and X. oryzae. Its ethylacetate extract contained canonical lipopeptides alongside rare metabolites like alkaloids and a unique bioactive amino acid, suggesting synergistic antimicrobial efficacy. This study highlights Cat Ba's macroalgae as a rich source of bioactive microorganisms and compounds, offering potential for novel natural products derived from host–microbe interactions.
Đặc Điểm Trường Dòng Chảy trong Mùa Gió Tây Nam một Số Bãi Cát Khu Vực Quần Đảo Cát Bà (Characteristics of Hydrodynamic Current Fields during the Southwest Monsoon Season at Selected Sandy Beaches in the Cat Ba Archipelago)
Under extreme weather conditions, sandy beaches in the Cat Ba Archipelago—including Cat Co I, Cat Co III, and Tung Thu—experience hazardous rip currents exceeding 50 cm/s, posing significant risks to swimmers and contributing to shoreline erosion. During the Southwest monsoon season, such currents are generally absent under spring tide conditions, but strong alongshore flows persist due to coastal morphology. The study used the MIKE21 hydrodynamic model to analyze current fields, revealing that while rip currents and nearshore eddies are rare during typical monsoon periods, extreme events trigger unstable beach dynamics. This research highlights the vulnerability of these UNESCO-recognized beaches to erosion and safety hazards under changing environmental conditions.
Prioritizing Muslim-Friendly Tourism Factors in Ha Long Bay, Vietnam
A groundbreaking study identifies halal infrastructure and human resource development as the top priorities for transforming Ha Long Bay, Vietnam, into a Muslim-friendly tourism destination. Using a hybrid fuzzy analytic hierarchy process-ViseKriterijumska Optimizacija I Kompromisno Resenje (multi-criteria optimization) framework, the research synthesized insights from 35 experts to create a quantifiable roadmap for heritage managers. The findings reveal that intangible capabilities, such as cultural intelligence, provide a more sustainable competitive advantage than replicable assets in niche markets with high cultural distance. This capability-driven approach offers a strategic solution for balancing market diversification and site integrity while successfully engaging the global Islamic travel market.
Community Perceptions of Harmful Algal Blooms, the Socioeconomic Implications, and Policies of Mitigation: A Case Study of Ha Long Bay, Vietnam
A study on Ha Long Bay, Vietnam, reveals that harmful algal blooms (HABs) are often underestimated by local communities due to limited public awareness and understanding. Perceptions of HAB threats varied significantly across sectors, with those in tourism and aquaculture—sectors directly impacted by HABs—underestimating the risks. The research, combining community questionnaires and expert interviews, highlights the need for improved government communication on HABs and tailored policies to mitigate socioeconomic impacts. This work contributes to a growing but still limited body of evidence on public perceptions of coastal HABs, offering insights crucial for long-term solutions.
Di sản Vịnh Hạ Long trong tầm nhìn liên giá trị
Ha Long Bay, recognized for its outstanding natural landscape and geological significance since 1994, has expanded its global heritage status to include the Cat Ba Archipelago in 2023. This study proposes a developmental orientation for Ha Long Bay by examining its inter-value relationships within the broader cultural context of Quang Ninh Province. Through an integrated approach, it explores the potential additional values beyond tourism, offering insights into sustainable socio-economic development and heritage conservation. The research employs an inter-value perspective to assess Ha Long Bay's multifaceted contributions to global heritage systems.
Insect diversity and new records from mangrove forests of Cat Ba National Park, Vietnam, using multi-method sampling
A groundbreaking survey of insect diversity in the mangrove forests of Cat Ba National Park, Vietnam, reveals 163 species across 11 orders, with eight new to science and four newly recorded for Vietnam. Hemiptera dominated the findings (37 species), followed by Lepidoptera and Diptera, underscoring mangroves as critical biodiversity hotspots. Multi-method sampling—sweep nets, light traps, and yellow pan traps—identified sweep nets as most effective, particularly for Hemiptera and Hymenoptera, while light traps excelled at capturing Lepidoptera. This study provides the first comprehensive baseline for insect diversity in Cat Ba's mangroves, offering insights applicable to understudied Southeast Asian ecosystems.
Monogenean infections in rabbitfish ( Siganus spp.) From the Cat Ba Archipelago Vietnam
A comprehensive study of monogenean parasite infections in rabbitfish from the Cat Ba Archipelago, Vietnam, reveals high infection rates (>75%) and significant variability across species. The white-spotted spinefoot (Siganus canaliculatus) exhibited a higher mean intensity of infection (12.3 parasites per host) compared to the mottled spinefoot (Siganus fuscescens), which averaged 8.0. Six monogenean species were identified, including five shared between both fish species, marking the first confirmed records of these parasites in Vietnamese rabbitfish. The research employed morphological identification techniques, such as staining with carmin alum or trichome gomori, to analyze samples collected between 2009 and 2025.
Overtourism: An Emerging issue in Ha Long Bay, Quang Ninh
Overtourism in Ha Long Bay is severely straining the region's natural and cultural resources, threatening its long-term sustainability. The study identifies critical challenges including environmental degradation, sociocultural disruptions, and diminished visitor satisfaction due to overcrowding and inadequate tourism management. Key contributing factors include exceeded carrying capacity, localized overload, and insufficient public awareness of responsible tourism practices. Solutions proposed involve stricter visitor number controls, diversification of tourism products, promotion of eco-tourism, enhanced governance, stricter environmental regulations, and widespread awareness campaigns. A coordinated approach is deemed essential to balance tourism growth with the preservation of Ha Long Bay's unique heritage status.
Variation of carbonate buffer and air- water (CO(_{2})) flux in Ha Long Bay
Ha Long Bay consistently acts as a sink for atmospheric CO₂, absorbing carbon dioxide at rates that vary between seasons. During the dry season (2023–2024), the bay's carbonate buffer system—comprising bicarbonate (HCO₃⁻), carbonate (CO₃²⁻), and dissolved CO₂—showed higher pH, salinity, and temperature compared to the rainy season, with HCO₃⁻ dominating (85.97–88.02%) while CO₃²⁻ and CO₂ accounted for smaller fractions. The partial pressure of CO₂ in water (pCO₂) was lower and more stable in the dry season (average 99.16 µatm), contrasting with higher variability in the rainy season (average 164.78 µatm). CO₂ flux measurements revealed stronger absorption during the dry season (-12.9 ± 0.8 mmol/m²/day) than the rainy season (-10.2 ± 1.0 mmol/m²/day), with spatial and diurnal patterns further influencing exchange rates. These findings highlight Ha Long Bay's dynamic role in regional carbon cycling, underscoring seasonal influences on its capacity to mitigate atmospheric CO₂.
Water quality of submarine caves and marine karst lakes in Cat Ba Archipelago (Hai Phong, Vietnam)
Submarine caves and marine karst lakes in Vietnam's Cat Ba Archipelago exhibit distinct water quality characteristics, with caves showing higher and more stable salinity but lower dissolved oxygen levels compared to lakes. Research conducted in 2019 revealed that water self-purification improves during the rainy season, though pollution by ammonium was detected in several lakes (Ang Vem, Ba Man, Ba Mat, Ang Gay) during this period. While no evidence of organic contamination was found, elevated nitrate and phosphate concentrations were recorded, along with the presence of H2S gas, which may impact aquatic organisms. The study highlights seasonal variations in water quality, emphasizing the need for monitoring to preserve these unique ecosystems within a UNESCO World Heritage Site.
Assessment of Tourism Activities and Environmental Impacts on Ecosystems in Ha Long Bay World Natural Heritage Site
Tourism in Ha Long Bay, a UNESCO World Natural Heritage site, significantly impacts its ecosystems, with 32.5% of reported effects on mangroves, 36.4% on coral reefs, and 34.4% on beach activities. Despite advancements in waste management and biodiversity conservation, environmental pollution from boats and tourist waste continues to threaten endemic flora and fauna. The study underscores the need for increased investment, stricter management measures, and greater awareness among local communities and tourists to ensure sustainable protection of this natural heritage site.
Sponge Spicules in Sediments: A Proxy for Past and Present Sponge Fauna Assessment in Ha Long Bay (Vietnam)
Sponge spicules preserved in sediments offer a novel, non-destructive method to assess past and present sponge fauna diversity in Ha Long Bay's karst lakes. The study identified distinct sponge taxa compositions across four lakes and surrounding sea areas, with significant differences between inland and marine environments. Notably, four sponge genera previously unrecorded in the South China Sea were detected, highlighting the potential of sedimentary spicules as a proxy for comprehensive biodiversity studies. This approach circumvents the challenges of studying cryptic sponges, providing valuable insights into their ecological distribution and historical presence.
The impact of the COVID-19 pandemic on the seawater quality of Ha Long Bay, Vietnam
A significant reduction in anthropogenic impacts on the seawater quality of Ha Long Bay, Vietnamwas observed during the COVID-19 pandemic year (2020) compared to previous years (2016–2019). Analysis using a Water Quality Index (WQI) across 28 sampling sites revealed that while overall water quality remained acceptable, 17 sites showed markedly lesser impacts in 2020. Ten sites remained unaffected, and one site exhibited increased impact. This study highlights the pandemic's unintended environmental benefit by providing insights into human activity's influence on marine ecosystems.
The occurrence of potential pathogenic antibiotic-resistant bacteria in the marine environment in Ha Long Bay, Vietnam
A concerning prevalence of antibiotic-resistant, potentially pathogenic bacteria was found in Ha Long Bay's marine environment, with 93.3% of sampling stations harboring such organisms. Dominant genera included Vibrio (29.3%), Pseudomonas (23.3%), and Staphylococcus (8.6%), while key pathogens like Vibrio alginolyticus (25 isolates) and Vibrioparahaemolyticus (5 isolates) showed high resistance to multiple antibiotics, including 100% resistance to amoxicillin and piperacillin. Over half of the isolates were multidrug-resistant, highlighting a significant threat to human health. The study analyzed 30 surface water samples from the bay, identifying 24 bacterial genera and 61 potential pathogens, emphasizing the need for genomic surveillance to mitigate the spread of resistant bacteria in this UNESCO World Heritage Site.
The variation of organic carbon concentrations in the surface water in Cua Luc Bay, Ha Long Bay, Vietnam
A 2023 study of Cua Luc Bay, Ha Long Bay, Vietnam, revealed that dissolved organic carbon (DOC) and particulate organic carbon (POC) concentrations averaged 1.59 ± 0.21 mgC/L and 0.74 ± 0.35 mgC/L, respectively—levels notably lower than those in other Vietnamese rivers and estuaries. The analysis of DOC/POC and POC/Chl-a ratios indicated significant fluctuations in the bay's water environment, suggesting dynamic carbon cycling processes. Researchers surveyed 22 stations to assess organic carbon variation, providing insights into the marine carbon system's behavior in this UNESCO-listed region.
A Study on the Behavior of Tourists and Suggesting Appropriate Leisure Activities in the Ha Long Bay Bay – Vietnam
Tourist preferences for accommodation, attractions, dining, and transportation significantly shape the attractiveness of Ha Long Bay, Vietnam. Regression analysis indicates that diverse lodging options—ranging from hotels to homestays—enhance destination appeal, alongside engaging activities and local cuisine experiences. Efficient transportation networks further bolster tourist satisfaction. These findings provide actionable insights for policymakers and tourism stakeholders to refine leisure offerings and promote Ha Long Bay as a competitive global destination.
Assessment of Human-Induced Effects on Sea/Brackish Water Chlorophyll-a Concentration in Ha Long Bay of Vietnam with Google Earth Engine
A calibrated ocean chlorophyll 2-band (OC-2) model, applied to Sentinel-2 satellite imagery on Google Earth Engine, reveals that phytoplankton blooms thrive in Ha Long Bay during colder seasons (fall and winter), particularly near aquaculture, urban, and tourist zones. This study demonstrates a significant improvement in model accuracy—nearly doubling precision compared to uncalibrated OC-2—highlighting its potential for seawater quality monitoring. Coal mining activities, however, did not correlate with algae growth. The findings underscore the utility of Sentinel-2 data for environmental assessments while emphasizing the need for longer-term simulations and more in situ measurements, along with manual atmospheric correction, to refine coastal studies.
Before Rice and the First Rice: Archaeobotanical Study in Ha Long Bay, Northern Vietnam
A groundbreaking archaeobotanical study of Ha Long Bay, Vietnam, reveals that maritime hunter-gatherers exploited a diverse range of subtropical and tropical plants—including taros, yams, acorns, and palms—as early as 7,000–6,000 years BP, long before rice and millet farming. Analysis of micro plant remains, such as starches and phytoliths, from stone tools at the Cai Beo site provides unprecedented insight into pre-farming diets in Mainland Southeast Asia. The findings highlight the significance of roots and tubers in ancient subsistence economies and suggest early human interaction with local flora, contributing to population growth until around 4,500 years BP. Additionally, rice identified in this study represents one of the earliest known in the region, offering new perspectives on the transition from foraging to agriculture.
Estimation of Total Suspended Matter Concentration of Ha Long Bay, Vietnam, from Formosat-5 Image
Research demonstrates that Formosat-5 (FS5) satellite images can effectively estimate total suspended matter (TSM) concentrations in coastal waters, including UNESCO World Heritage Site Ha Long Bay, Vietnam. The study developed a linear regression model to correct atmospheric effects in FS5 data by comparing it with Landsat-8 OLI reflectance, achieving high accuracy (R²: 0.87–0.96). Applying existing TSM algorithms to the corrected FS5 images yielded results comparable to those derived from OLI (R²: 0.86–0.95) and validated against in situ measurements. Cross-comparisons with OLI-derived TSM data confirmed the reliability of FS5 for coastal water monitoring, offering a cost-effective alternative for high-resolution TSM estimation.
Plant species diversity and composition in limestone forests of the Vietnamese Cat Ba National Park
A study on the Cat Ba National Park, part of Ha Long Bay - Cat Ba Archipelago, reveals that plant species diversity is primarily driven by topography—specifically rock surface percentage and slope—rather than spatial isolation. The research identified 302 plant species across four distinct communities, with tree species making up half of the total richness. Contrary to expectations, isolated areas did not significantly contribute to biodiversity due to natural barriers like rough terrain that hinder seed dispersal. While non-tree species had no overall impact on tree regeneration, they negatively affected tree diversity in favorable lowland conditions, unlike harsh environments where such effects were absent. The findings highlight the importance of accessible lowland areas for high plant diversity but also note potential competition from non-tree species.
Rice and millet cultivated in Ha Long Bay of Northern Vietnam 4000 years ago
A groundbreaking study reveals that rice and foxtail millet were co-cultivated in Ha Long Bay, Vietnam, around 4000 years ago, marking the earliest evidence of such farming practices in northern Vietnam. The research, utilizing micro-plant remains analysis including phytoliths and starch, also identifies two distinct subsistence strategies among Neolithic cultural groups: the Trang Kenh people, with a cereal-based diet influenced by southern China, and the Ha Long people, who integrated rice and millet into their traditional hunter-gatherer food system. This finding sheds light on the diverse economic systems and cultural adaptations during the emergence of agriculture in Mainland Southeast Asia.
Cultural Tourism Development and Folk Festivals Management in North of Vietnam - Ha Long Bay, Thai Nguyen City and Hanoi
Folk festivals in Ha Long Bay, Thai Nguyen City, and Hanoi serve as vital pillars of local cultural life, significantly enriching the experiences of both residents and visitors. A systematic approach to integrating these festivals with cultural tourism can enhance their economic and social value while preserving their authenticity. The study employs an interdisciplinary method, combining historical and cultural analysis with statistical and comparative techniques, to uncover the relationships between legends and festivals. This dual approach yields both broad qualitative insights and specific quantitative findings, offering a comprehensive framework for sustainable development in the region.
Horseshoe bat species recorded in the mangrove ecosystem of the Cat Ba National Park, Northern Vietnam
Researchers document the presence of three horseshoe bat species—Marshall's, Pearson’s, and the least horseshoe bats—in the mangrove ecosystems of Cat Ba National Park, a key component of the Cat Ba Archipelago Biosphere Reserve. This marks the first recorded observation of these bats in such habitats within the park, with Pearson’s horseshoe bat identified as the most common species. The study combines morphological and acoustic analyses to characterize each species, while also highlighting the ecological significance of mangrove forests for bat research and conservation efforts.
Sedimentation Rate Estimation and Tracing Organic Carbon and Nutrients Sources in Sediment of Ha Long Bay (Vietnam)
Research on Ha Long Bay and the Cat Ba Archipelago reveals that sedimentation rates vary temporally due to anthropogenic influences, while spatial differences stem from varied sediment sources. A strong correlation (R² = 0.86) between nitrogen and phosphorus concentrations in sediments suggests these nutrients originate from a common source. The study employed sediment core analysis and geochemical tracing to unravel the complex interplay of natural and human-driven factors shaping the bay's sedimentary environment.
A New Species of Spongilla (Porifera, Demospongiae) from a Karst Lake in Ha Long Bay (Vietnam)
Researchers have identified Spongilla manconiae, a new species of freshwater sponge, thriving in the extreme and fluctuating conditions of Cahong Lake within Ha Long Bay's Cat Ba Archipelago. This discovery highlights the lake's unique environmental pressures, characterized by significant variations in salinity, temperature, and pH due to monsoonal influences, which typically deter most marine life. The study employed genetic barcoding using mitochondrial Cytochrome C Oxidase subunit 1 (COI) and nuclear Internal Transcribed Spacers (ITSs) markers, revealing substantial genetic divergence from other spongillid species, underscoring its distinct evolutionary path. This finding emphasizes the urgency to protect such fragile marine lake systems, which may serve as hotspots for rapid speciation processes.
Analisis Potensi Wisata Ha Long Bay Terhadap Perekonomian Vietnam
Ha Long Bay's tourism significantly boosts Vietnam's economy, contributing 9.3% to GDP growth and providing employment for 3.7% of the workforce. The study leverages national branding concepts to analyze these impacts, revealing that Ha Long Bay's UNESCO World Heritage status enhances its global competitiveness and attracts more tourists. Vietnam stands out as one of the top 10 countries for tourism sector recovery post-2008 financial crisis, underscoring the bay's economic resilience and appeal in the global tourism market.
Distribution and density of Lutraria rhynchaena Jonas, 1844 relate to sediment while reproduction shows multiple peaks per year in Cat Ba-Ha Long Bay, Vietnam
A study on Lutraria rhynchaena, a commercially valuable clam species, reveals that its distribution and density are closely tied to sediment types, with medium sand being the optimal substrate. The research, conducted from August 2017 to July 2018 in Cat Ba-Ha Long Bay, Vietnam, also identified three distinct spawning peaks per year—January, April, and September—suggesting a year-round reproductive cycle. These findings provide critical insights for sustainable fishery management, advocating for harvest bans during peak spawning months to protect the clam population's long-term viability.
Sponge’s biodiversity in the limestone islands in Vietnam sea
A comprehensive survey of sponge biodiversity in Vietnam's limestone islands, including Ha Long Bay and the Cat Ba Archipelago, identified 54 species across 33 genera and 24 families. Ha Long Bay exhibited the highest diversity (53 species), while the Ba Lua archipelago had the least (3 species). Sponges were most abundant in coral reefs (48 species) compared to mud or sand bottoms (4 species). Biomass varied significantly, with 11 sites showing high potential for medicinal drug development. The study, conducted between 2017 and 2020 across 41 sampling points, provides critical insights into the ecological richness of these UNESCO World Heritage Sites.
Water Quality Index Analysis of Water Pollution of Ha Long Bay, Vietnam
A comprehensive analysis of water quality in Ha Long Bay, Vietnam, reveals significant spatial variations in pollution levels. Using 14 water quality parameters from 41 sampling sites collected in 2019, the study identified four distinct clusters through cluster analysis and principal component analysis (PCA). The first principal component indicated that Cluster I and II sites exhibited higher overall pollution levels compared to Cluster III. Notably, the second principal component distinguished between organic and inorganic pollution, with Cluster I and II scoring high for organic pollution while Cluster II also showed elevated inorganic contamination. This suggests localized hotspots of water quality degradation within the bay, warranting targeted conservation efforts.
An Integrated Approach in Management of ‘Halong Bay – Cat Ba Limestone Island Marine Area’, Vietnam
Halong Bay and its adjacent Cat Ba and Long Chau archipelagos, recognized as a unique cluster of limestone islands with global heritage significance, face challenges due to administrative separation. Despite Halong Bay being designated a UNESCO World Natural Heritage Site in 1994, the proposal for Cat Ba-Long Chau's inclusion was only submitted in 2014. The study highlights that while these areas share geological and ecological similarities, their divided governance presents unprecedented institutional hurdles for UNESCO recognition. However, an integrated management approach was adopted in 2015, designating the 'Halong Bay – Catba limestone island marine area' as an Ecologically and Biologically Significant Marine Area (EBSA). This decision underscores the potential for sustainable conservation-based economic development, benefiting not only the local regions but also Vietnam and global heritage preservation efforts.
Marine biodiversity in Ha Long bay and Cat Ba archipelago
Ha Long Bay - Cat Ba Archipelago, Vietnam's largest limestone island system, exhibits exceptional marine biodiversity with 4,622 species of plants and animals, including 16 on the Vietnam Red List and 114 on the IUCN List. This diversity spans seven tropical limestone ecosystems—rainforest, cave, mangrove, tidal, coral reef, and soft-bottom—highlighting its global conservation value under UNESCO criteria (ix and x). The study, analyzing both terrestrial and marine species distribution, underscores the site's potential as a World Heritage Site due to its high endemism and rare species presence. Research involved systematic species documentation, emphasizing ecological significance for heritage designation.
You are here:
World Heritage Explorer > World Heritage Research > World Heritage Sites > Ha Long Bay - Cat Ba Archipelago