Marine litter pollution on coral reefs of Darvel Bay (East Sabah, Malaysia)

Marine litter pollution in inhabited and uninhabited Lakshadweep islands, Indian Ocean

The Lakshadweep archipelago, located in the Arabian Sea off India's southwestern coast, is renowned for its rich biodiversity and vibrant coral reefs. However, the region faces a growing environmental threat from marine debris, particularly plastic waste, which poses a significant challenge to its delicate ecosystem. To identify potential sources of pollution, we assessed environmental quality and ecological risk using indices such as the Clean Coast Index (CCI), Plastic Abundance Index (PAI), and Pollution Load Index (PLI). We also analyzed the spatial distribution of marine litter on Lakshadweep's beaches and mapped the annual wind direction. The study, conducted across six islands, recorded 3933 plastic litter items, with an average abundance of 0.77 ± 0.33 items/m2, making up 82.9 % of the total litter. The high mean values of CCI (17.98), PAI (5.39), and PLI (34.25) indicate severe ecological risk and critical pollution levels along the Lakshadweep coastline, driven by extensive macroplastic accumulation. Furthermore, the study highlights the influence of wind patterns on plastic movement across the islands. These findings provide essential insights for developing effective strategies to manage and mitigate marine litter, contributing to the broader effort to combat plastic pollution in the region.

Abundance, distribution, and seasonal variation of marine litter on the beaches of central Vietnam

This study investigates the abundance, distribution, and seasonal variation of marine litter across beaches in central Vietnam, using the Clean Coast Index (CCI) and Hazardous Index (HI) to assess pollution levels. A total of 16,118 litter items were recorded across 21 sampling sites, with plastics overwhelmingly dominant (96.48 %), followed by rubber (2.02 %) and paper (1.10 %), while glass, wood, and metal were minimal. The results reveal a significant seasonal influence on litter density, with higher accumulation during the rainy season due to increased runoff and riverine transport. The average litter density increased from 0.06 items/m2 in the dry season to 0.14 items/m2 in the rainy season (2022) and from 0.06 items/m2 to 0.11 items/m2 (2023). Statistical analyses using PCA demonstrated that 93.40 % of the total variance is explained by the first two principal components, highlighting the impact of seasonal and spatial pollution dynamics. HCA identified distinct site groupings based on pollution intensity, reinforcing the influence of urbanization, tourism, and human activities on litter accumulation. While most beaches were classified as "very clean to clean", urban and high-tourism areas exhibited increased pollution, emphasizing the need for targeted waste management efforts. These findings underscore the urgent necessity for enhanced waste management policies, stricter regulations on plastic usage, improved community engagement, and continuous monitoring to mitigate marine pollution and safeguard coastal ecosystems in Vietnam.

Coastal beach ecosystems contaminated by marine litter: Impact on coastal biodiversity, tourism, and environmental sustainability

This study examined the abundance, composition, sources, and pollution status of marine macro litter (>2.5 cm) at four beaches in Sri Lanka (Kallady, Negombo, Kandakuliya, and Balapitiya), located along the coastline of the northern Indian Ocean. Clean Coast Index (CCI), Plastic Abundance Index (PAI), Hazardous Item Index (HII), and Environmental Status Index (ESI) were used to evaluate the pollution levels. A total of 10,873 litter items were collected from four beaches representing 11 typologies. The average density of the litter collected was 0.7-1.2 items/m2. Plastic items constituted the majority of litter found, with a percentage of 51%. Kallady Beach was classified as "extremely dirty," while the others were rated as "dirty" according to the CCI. All beaches fell under category "II" on the HII. PAI indicated high and moderate plastic contamination, and the ESI classified all sites as having a "bad" environmental status. The majority of litter originated from land-based sources, including unsustainable fishing practices, poor waste management, and harmful recreational activities. The findings highlight the urgent need for comprehensive marine and coastal management frameworks to address these challenges. Despite existing awareness and cleanup efforts, the study calls for innovative waste management solutions, enhanced regulations, corporate responsibility, and further research to protect Sri Lanka's coastal ecosystems. These effective management steps are essential to mitigate marine litter and ensure the long-term health of these sensitive ecosystems.

Multidimensional risk assessment of marine litter pollution in the ecologically fragile coral atolls of India

Marine litter (ML), predominantly plastic, threatens oceanic biodiversity and ecosystem functioning globally. However, limited knowledge exists about its impact on India's coastal areas, particularly the Lakshadweep Islands, the nation's sole coral atolls. Within this frame of reference, the present study comprehensively investigated the distribution, abundance, typology, and ecological risks associated with ML across 28 beaches and three lagoon reef stations on Kavaratti Island. A total of 32,710 litter items, divided into 11 categories, were found with an average litter density of 0.82 ± 0.80 items/m2. Plastic litter emerged as the most prevalent category across the study area, constituting 63.7% of the total, and public littering was identified as the primary source (43%). Assessments of environmental quality and ecological risk, employing indices like the Clean Coast Index (CCI), Plastic Abundance Index (PAI), Hazardous Litter Index (HLI), Pollution Load Index (PLI), and Environmental Status Index (ESI), identified the Lakshadweep coastline as being at risk due to litter pollution and hazardous litter abundance. The mean concentration of trapped litter on the coral reef was estimated at 1.73 ± 0.46 items/m2, with a PLI value of 53.4, indicating an alarming ecological risk and highly perilous condition for the lagoon reef ecosystem. Approximately 5.94% ± 0.18% of coral colonies, particularly of the Porites genus, were found in contact with ML, with a significant proportion displaying signs of disease and tissue loss (59.37%), and partial bleaching or pale (14.86%). The results highlight the growing threat of litter to beach and coral communities, emphasizing the urgent need for effective regional litter management, strengthened policies for banning and phasing out single-use plastics in Lakshadweep, and efficient transportation of non-biodegradable waste to authorized recyclers on the mainland.

Unveiling the risk of marine litter and derelict fishing gear in remote coral reefs of the Andaman and Nicobar Islands, North Indian Ocean

An increasing amount of plastic litter and derelict fishing gear in the global oceans poses significant threats to corals and reef-associated marine biota. In this context, an underwater marine litter survey was conducted along the fringing coral reefs in the Andaman and Nicobar Islands- a remote archipelago in the Bay of Bengal, Northern Indian Ocean. The result revealed entanglement and smothering of coral colonies by plastic and derelict fishing gear. The survey recorded an average litter density of 0.42 ± 0.08 items/m2 (range: 0.23 ± 0.02 to 0.71 ± 0.09) and a mean mass of 138.61 ± 42.15 g/m2 (range: 70.17 ± 7.74 to 303.4 ± 2.55). Plastic was the most dominant litter (60.82 %) recorded in the reef environment. Derelict fishing gear made of plastic comprised 33.65 % of the total litter. Plastic Abundance Index (PAI), Hazardous Item Index (HII), and Clean Environment Index (CEI) were used to assess the ecological impact of marine litter. These indices highlighted the significant risks posed by marine litter to the coral reef environment. The finding helps to strengthen the assessment of marine litter in remote islands and underscores the urgent need for improved waste management, stricter regulations on the disposal of fishing gear, and effective removal of derelict fishing gear from the coral reef environments. Present study offers actionable insights for policymakers and stakeholders to prioritize interventions for managing marine litter to safeguard vulnerable coral reef systems.

Daily accumulation of marine litter in a clam culture area in Can Gio District, Ho Chi Minh City, Vietnam

The health of humans, the economy, and the marine ecology are all seriously threatened by marine litter. Therefore, quantifying the scope of the issue is gaining more and more attention. Studying beach litter accumulation is one of the approaches to investigating its flows into the marine environment. This study assessed beach litter composition and abundance in a clam culture area in Can Thanh Town, Can Gio District, during a daily moon cycle. From the higher beach limit (bushes or rocks), a transect with a length of 50 m parallel to the seawater line and a width of 10 m was set to collect all litter. The litters were then cleaned, weighted, and classified according to NOAA's marine debris guidance, with modifications to the litter category list. As a result, the dominant materials collected were plastic, accounting for more than 90% of all items found throughout the surveys. A total of 3617 items weighing 21,456.674 g were recorded, corresponding to an accumulation rate of 0.24 items/day.m2 (1.43 g/day.m2). Despite the research location's low population density, most items were made of foam and bottle wrappers. Brand auditing showed that PepsiCo, Coca-Cola, and Tan Hiep Phat were the top three recognized brands in the beverage industry. This raises an issue in managing beach litter in Can Thanh Town, and the source of such litter could be the mishandling of litter drifting in from other places.

Cigarette butts in Vietnam's marine environments: From pollution to solutions and prospects

Cigarette butts contain over 4000 toxic chemicals, including nicotine, tar, and heavy metals. More than 90 % of cigarettes sold today feature single-use plastic filters composed of cellulose acetate fibers and various additives. Cigarette butts are hazardous waste that pose significant risks to ecosystems and human health. Littered cigarette butts can act as an essential vehicle for toxic chemicals in the water environment. Cigarette butts contribute to gradual environmental degradation by releasing heavy metals such as lead (Pb), cadmium (Cd), chromium (Cr), copper (Cu), vanadium (V), nickel (Ni), and arsenic (As). Recent reports highlight the alarming increase in cigarette butt pollution on beaches, emphasizing the significance of commercial cigarette filters as single-use plastics and the primary contributors to this environmental threat. Given their potential toxicity, the research community has increasingly focused on understanding the profound impact of cigarette butt pollution on freshwater bodies, marine ecosystems, and terrestrial environments. However, there remains a considerable gap in knowledge regarding the extent of cigarette butt pollution, especially on Vietnam's beaches. While cigarette butts are a pervasive form of litter globally, little is known about their environmental effects, accumulation patterns, potential toxicity, and impacts on the coastline of Vietnam. This underscores the need for an in-depth investigation into this issue, expressing disappointment over the limited research conducted in coastal areas thus far. This article advocates for active participation from the scientific community to bridge this gap, asserting that collaborative research efforts will bring attention to and address the critical issue of cigarette butt pollution in Vietnam's regions and potential harm to natural ecosystems. Furthermore, enhancing research efforts to understand and mitigate cigarette butt pollution on Vietnam's beaches is crucial for achieving sustainable development goals (SDGs).

Assessment of transboundary macro-litter on the remote island of Andaman and Nicobar: Unveiling the governing factors and risk assessment

The increasing occurrence of mismanaged plastic litter along India's coastline and the ominous challenges it poses to biodiversity and ecosystem health is a growing environmental concern. To address this issue, we comprehensively investigated the abundance, composition, and probable sources of marine litter on North Cinque Island, a remote uninhabited island in the Andaman and Nicobar archipelago, Bay of Bengal. This island is a designated wildlife sanctuary and serves as an important nesting site for Green, Hawksbill and Leatherback turtles. A total of 6227 litter items were enumerated, with an average concentration of 0.12 items/m2, representing 20 diverse litter types, with plastic dominating the litter composition (86 %). The cleanliness and environmental hazards of the coast due to the litter were assessed using different indices such as the Clean Coast Index (CCI), Plastic Accumulation Index (PAI), Hazardous Item Index (HII), and Clean Environment Index (CEI). CCI indicates the moderately clean-to-clean status of the surveyed sites. PAI points to low to moderate accumulation of plastic litter. HII of all five coasts fell in category II, suggesting a moderate abundance of hazardous items that can inflict injuries to the foraging turtle and their hatchlings. The CEI articulates the moderately clean to very clean status of the sites. Litter brand audit suggests a considerable amount of stranded litter on the coasts was transboundary and originated from six Indian Ocean Rim Countries (IORC), namely Thailand, Myanmar, Malaysia, Indonesia, Sri Lanka, and UAE. Joint solid waste management by the IORC is the need of the hour to avert litter accumulation on the pristine, remote islands.

Assessment of marine litter interactions with urban coral reefs in Okinawa, Japan

This study assessed different reef zones (lagoon, reef crest, reef slope) in three urban locations around Okinawa Island (Mizugama, Ginowan, Sunabe) and two marine protected areas around nearby Aka Island (Hizushi, Sakubaru) for marine litter pollution and litter interactions with reef organisms. A total reef area of 2250 m2 was surveyed by scuba diving, and 46 marine litter items were recorded. Litter density ranged from 0.01 to 0.05 items/m2, and plastics (76.09 %) and metals (15.22 %) were the most common litter types. The substrates for litter items were live corals (52.17 %), followed by dead corals and algae (26.09 %), sand (13.04 %), and rocks (8.70 %). Litter items on live corals were entangled exclusively with branching Acropora spp. (95.83 %) and Pocillopora spp. (4.17 %). This study highlights the need to protect coral reef ecosystems from the impacts of urbanisation in order to conserve and sustain their ecological and economic benefits.

Marine macrolitter and cigarette butts hazard multiple-use marine protected area and fishing community at Brazil

Wide marine litter (ML) contamination impacts human health and economic sectors including fishing, navigation, and tourism. Perequê beach, Brazil, is an authentic fishing community within a touristic multiple-use marine protected area. However, no ML contamination monitoring were so far performed in the region. This study evaluated the spatiotemporal abundance, composition, sources, and associated ML hazards at Perequê beach using a multi-index approach. The 2579 items (0.64 ± 0.72 items.m-2) yielded a high contamination level (CCI = 12.6 ± 14.4) with plastic (44.6-50.9 %) and cigarette butts (20.6-28.4 %) prevalence, while primary sources were smoking (cigarette butts, lighters, others-21.2-30.1 %) and packaging (17.8-22.8 %). Levels of pollutants leaked from cigarette butts (CBPI = 30.5 ± 47.5) and hazardous items (HALI = 3.06 ± 2.64) were among the highest globally. Heightened levels occurred in summer, at dry sand strip, where short-term buoyant items prevailed. Multi-indexing approaches offer valuable insights for local authorities to implement mitigation programs, while contributing to global discussions, promoting awareness, and facilitating replicability.

Marine litter along the Peruvian coast: spatiotemporal composition, sources, hazard, and human modification relations

Marine litter (ML) represents an escalating environmental issue, particularly in Latin America, where comprehensive studies are scarce despite critical solid waste management challenges and continuous human modification occurring on the coasts. To contribute to the knowledge of ML in the southeast Pacific, this study examined contamination across 10 beaches on Peru's extensive coast. Overall, ML contamination was categorized as moderate (with an ML concentration of 0.49 ± 0.64 items∙m-2), while significantly differing between summer (dirty with an ML concentration of 0.56 ± 0.66 items∙m-2) and winter (moderate with an ML concentration of 0.47 ± 0.60 items∙m-2). Three beaches were extremely dirty (concentrations of ML exceeded 1.0 items∙m-2). Predominant materials, items, and sources were plastic, cigarette butts (CBs), and mixed packaging. The Peruvian coast faced CB leachate impact (CBPI = 3.5 ± 3.5), reaching severe levels on two beaches, with considerable hazardous litter (HALI = 3.0 ± 2.9). Additionally, a higher degree of human modification was associated with higher ML levels along the coast.

Rethinking plastic entrapment: Misconceptions and implications for ecosystem services in coastal habitats

This study addresses the pressing issue of plastic pollution in coastal and marine ecosystems, challenging the misconception that the entrapment of plastics can be considered as an ecosystem service. We differentiate between essential natural processes that sustain ecological balance and biodiversity and the detrimental accumulation of synthetic polymers. The pathways through which plastics enter these environments-from terrestrial to maritime sources-are examined, alongside their pervasive impacts on crucial ecosystem services such as habitat quality, the vitality of marine species, and nutrient cycling. Our findings highlight the paradox of resilience and vulnerability in these ecosystems: while capable of accumulating substantial amounts of plastic debris, they suffer long-lasting ecological, socio-economic, and health repercussions. We argue for a paradigm shift in management strategies aimed at reducing plastic production at the source, improving waste management practices, conducting targeted cleanup operations, and rehabilitating impacted ecosystems. Emphasizing a comprehensive understanding of plastic pollution is vital for framing effective solutions and necessitates a reevaluation of societal, industrial, and regulatory frameworks. This shift is imperative not only to address current pollution levels but also to safeguard and sustain the functionality of coastal ecosystems, ensuring their ability to continue providing essential services and supporting biodiversity.

Marine litter along the shores of the Persian Gulf, Iran

Plastic wastes -including cigarette butts (CBs)- are dangerous for marine ecosystems not only because they contain hazardous chemicals but also because they can finally turn into micro- or even nano-particles that may be ingested by micro- and macro-fauna. Even large pieces of plastics can trap animals. In this research, the pollution status of macroplastics (abundance, size, type, and colour) and cigarette butts (CBs, number/m2) on the northern coasts of the Persian Gulf has been investigated. A total of 19 stations were explored in Bushehr province (Iran), which covers a length equivalent to 160 km of the Persian Gulf coastline. Among the collected plastic waste (2992 items), disposable mugs were the most frequent (18 %). Plastics with sizes 5-15 cm were the most abundant, and the most common type of plastic was PET (P-value <0.05). The origin of most macroplastics was domestic (2269 items). According to the Index of Clean Coasts (ICC), most surveyed beaches were extremely dirty. The average number and density of CBs in this study were 220 and 2.45 items/m2, respectively. Household litter was the most abundant type of waste in the studied beaches, and this problem can be better managed by training and improving the waste disposal culture. In general, it is suggested that an integrated and enhanced management for fishing, sewage and surface water disposal, and sandy recreational beaches be implemented in Bushehr to control plastic waste.

Identifying potential high-risk zones for land-derived plastic litter to marine megafauna and key habitats within the North Atlantic

The pervasive use of plastic in modern society has led to plastic litter becoming ubiquitous within the ocean. Land-based sources of plastic litter are thought to account for the majority of plastic pollution in the marine environment, with plastic bags, bottles, wrappers, food containers and cutlery among the most common items found. In the marine environment, plastic is a transboundary pollutant, with the potential to cause damage far beyond the political borders from where it originated, making the management of this global pollutant particularly complex. In this study, the risks of land-derived plastic litter (LDPL) to major groups of marine megafauna - seabirds, cetaceans, pinnipeds, elasmobranchs, turtles, sirenians, tuna and billfish - and a selection of productive and biodiverse biogenic habitats - coral reefs, mangroves, seagrass, saltmarsh and kelp beds - were analysed using a Spatial Risk Assessment approach. The approach combines metrics for vulnerability (mechanism of harm for megafauna group or habitat), hazard (plastic abundance) and exposure (distribution of group or habitat). Several potential high-risk zones (HRZs) across the North Atlantic were highlighted, including the Azores, the UK, the French and US Atlantic coasts, and the US Gulf of Mexico. Whilst much of the modelled LDPL driving risk in the UK originated from domestic sources, in other HRZs, such as the Azores archipelago and the US Gulf of Mexico, plastic originated almost exclusively from external (non-domestic) sources. LDPL from Caribbean islands - some of the largest generators of marine plastic pollution in the dataset of river plastic emissions used in the study - was noted as a significant input to HRZs across both sides of the Atlantic. These findings highlight the potential of Spatial Risk Assessment analyses to determine the location of HRZs and understand where plastic debris monitoring and management should be prioritised, enabling more efficient deployment of interventions and mitigation measures.

Plastic pollution in a coral reef climate refuge: Occurrence of anthropogenic debris, microplastics, and plasticizers in the Gulf of Aqaba

The Gulf of Aqaba in the northern Red Sea, considered a coral reef refuge from the negative effects of climate change, is however being subjected to increasing amounts of plastic contamination. We quantified the levels of benthic plastic debris, microplastics, and plasticizers within the coral reef's surrounding seawater and sediment over time. Our results indicate that the coral reefs of the GoA have relatively lower levels of plastic pollution compared to reefs in other regions. The measured benthic debris in the Red Sea reefs was found to be 0.093 ± 0.091 item/m2 and fell within the reported levels found in other tropical coral reefs, with boating and fishing materials being the most abundant type. Deep mesophotic reefs were found to have significantly higher levels of benthic plastic debris compared to the shallower reefs. Microplastic levels in the surrounding seawater of the reef were 0.516 ± 0.317 microplastics/m3. These concentrations in the reef's surrounding waters are comparable to the levels observed in surface waters from the central Red Sea. The target plasticizers appeared infrequently in samples, and the concentrations for the majority of them were below the level of quantification (LOQ = 14.7 ng/l for water and 14.7 ng/g for sediment). The findings from this study provide a valuable scientific basis for shaping regional policies and implementing management strategies aimed at controlling and mitigating plastic pollution. Such policies can ensure the long-term protection of the reefs in the northern Red Sea, turning them into a secure coral refuge shielded from both global and local anthropogenic stressors.

A new hotspot of macro-litter in the Rutland Island, South Andaman, India: menace from IORC

Supralittoral zones of 13 sandy beaches of remote Rutland Island were divided into three zones to identify the litter contamination, its source, pathway of plastic transport to determine the level of macro-litter contamination, and its impact on coastal biota. Owing to the floral and faunal diversity, apart of the study area is protected under Mahatma Gandhi Marine National Park (MGMNP). The supralittoral zones of each sandy beach (between low-tide and high-tide line) were individually calculated from 2021 Landsat-8 satellite imagery before conducting the field survey. The total area of the surveyed beaches was 0.52 km2 (5,20,020.79 m2), and 317,565 litters representing 27 distinct litter types were enumerated. Two beaches in Zone-II and six in Zone-III were clean; however, all five in Zone-I were very dirty. The highest litter density (1.03 items/m2) was observed in Photo Nallah 1 and Photo Nallah 2, whereas the lowest (0.09 items/m2) was observed in Jahaji Beach. According to the Clean Coast Index (CCI), Jahaji Beach (Zone-III) is the very cleanest beach (1.74) while other beaches of Zone-II and Zone-III are clean. The findings of the Plastic Abundance Index (PAI) indicate that Zone-II and Zone-III beaches have a low abundance of plastics (< 1), while two beaches of Zone-I, viz., Katla Dera and Dhani Nallah, exhibited a moderate abundance of plastics (< 4) while a high abundance of plastics (< 8) was observed in the rest of three beaches of the same zone. The primary contributor of litter on Rutland's beaches was plastic polymers (60-99%), which were presumed to originate from the Indian Ocean Rim Countries (IORC). A collective litter management initiative by the IORC is essential in preventing littering on remote islands.

The occurrence, speciation, and ecological effect of plastic pollution in the bay ecosystems

Bay is a unique part of the ecosystem, acting as the intersection for marine and terrestrial systems and hosting diverse biological organisms. The ubiquitous application of plastics has resulted in a massive amount of plastic waste released and accumulated in the bay ecosystem, posing significant ecological effects. Thus, thoroughly understanding plastic pollution's occurrence, speciation, and ecological effect in the bay ecosystems is of vital importance. We conducted a comprehensive review on the sources and distribution of plastics in the bay ecosystem, and the associate ecological effects, from individual toxicity to trophic transfer in ecosystems. Among bay areas around the world, the concentrations of microplastics vary from 0.01 to 3.62 × 10⁵ item/m³ in seawater and 0 to 6.75 × 10⁵ item/kg in sediment. Small-sized plastic particles (mostly <2 mm) were widely reported in bay organisms with the concentration range of 0 to 22.5 item/ind. Besides, the toxicity of plastics on marine organisms has been documented in terms of mortality, growth, development, reproduction, enzyme activity and transcription. Since abundance of small plastic particles (e.g., micro- and nano-scale) is far greater than large plastic debris in the bay ecosystems, in-depth risk assessment of small-sized plastics needs to be conducted under environmentally realistic conditions. Our review could provide a better understanding on the occurrence, speciation, and ecological effect of plastic pollution in the bay ecosystems.

Baseline marine litter abundance and distribution on Saint Martin Island, Bay of Bengal, Bangladesh

Baseline marine litter abundance and distribution on Saint Martin Island, Bay of Bengal, were assessed. Seventy-two transects (100-150 m) along 12 km of coastline were surveyed for litter items every two weeks for two months. The most abundant items were polythene bags, food wrappers, plastic bottles/caps, straws, styrofoam, plastic cups, plastic fragments, fishing nets, clothes, and rubber buoys. Tourism, local markets, hotels, domestic waste, and fishing activities were primary sources of marine litter. According to the mean clean coast index (CCI), all transects were clean, of which 11.3 % and 14.1 % of sandy beaches and rocky shores with sandy beaches were reported dirty, respectively. Northern Saint Martin Island comprised sandy beaches (2.8 %) and was extremely dirty. In addition, plastic abundance index (PAI) analysis showed that 24 % of sites, out of 72 sites, were under "very high abundance", 33 % were "high abundance", 33 % showed "moderate abundance", and 4 % were classified as "low abundance". Establishing baseline results of marine litter abundance and distribution on Saint Martin Island may help improve island conservation and mitigation strategies (e.g., improved waste management, beach cleaning activities to raise public awareness, local government litter reduction policies, and increase local pro-environmental behavioral change).

Priorities to inform research on marine plastic pollution in Southeast Asia

Southeast Asia is considered to have some of the highest levels of marine plastic pollution in the world. It is therefore vitally important to increase our understanding of the impacts and risks of plastic pollution to marine ecosystems and the essential services they provide to support the development of mitigation measures in the region. An interdisciplinary, international network of experts (Australia, Indonesia, Ireland, Malaysia, the Philippines, Singapore, Thailand, the United Kingdom, and Vietnam) set a research agenda for marine plastic pollution in the region, synthesizing current knowledge and highlighting areas for further research in Southeast Asia. Using an inductive method, 21 research questions emerged under five non-predefined key themes, grouping them according to which: (1) characterise marine plastic pollution in Southeast Asia; (2) explore its movement and fate across the region; (3) describe the biological and chemical modifications marine plastic pollution undergoes; (4) detail its environmental, social, and economic impacts; and, finally, (5) target regional policies and possible solutions. Questions relating to these research priority areas highlight the importance of better understanding the fate of marine plastic pollution, its degradation, and the impacts and risks it can generate across communities and different ecosystem services. Knowledge of these aspects will help support actions which currently suffer from transboundary problems, lack of responsibility, and inaction to tackle the issue from its point source in the region. Being profoundly affected by marine plastic pollution, Southeast Asian countries provide an opportunity to test the effectiveness of innovative and socially inclusive changes in marine plastic governance, as well as both high and low-tech solutions, which can offer insights and actionable models to the rest of the world.

Checklist of coral reef fishes of Darvel Bay, Sabah, Malaysian Coral Triangle, with a note on the biodiversity and community structure

The Darvel Bay is a large semi-enclosed bay with spectacular natural land and seascape. The inward side of the Bay has only been recently known to be an important foraging ground for the endangered, threatened and protected (ETP) elasmobranch species, such as the Whale Shark and mobulid rays. Following a recent scientific expedition, we present a checklist of the coral reef fishes of Darvel Bay. A note on the biodiversity and community structure is presented, based on our analysis using diversity indices, univariate and multivariate approaches. Seven natural coral reefs comprising two fringing reefs and five patch reefs, were surveyed at 10 m depth using underwater visual census (UVC) and baited remote underwater video station (BRUVS) methods. A diverse list of 66 species of reef fishes from 17 families is recorded. However, this is overwhelmingly dominated by the small-sized omnivorous damselfish, family Pomacentridae (62%; N = 1485 individuals). Species richness and abundance were observed to increase at sites surveyed furthest from the coast within the Bay. Significantly distinct reef fish assemblages were observed between three priori groups, based on proximity to shore (ANOSIM, R = 0.65, p < 0.05). SIMPER analysis further revealed that 22 species of the total reef fish species recorded drive 76% dissimilarities between the groups. The pattern of the reef fish communities observed, reflected as a logseries distribution model, is that commonly found in disturbed habitats or habitats characterised by restricted resources in a community, where the dominant species takes up a high proportion of available resources. The ecological indices (Shannon-Wiener Diversity Index, 2.05; Simpson Index of Diversity, 0.79; Simpson Dominance Index, 0.20; and Pielou's Evenness Index, 0.43), all reflect the relatively low diversity and uneven species distribution of the reef fish community. We conclude that the present status of the coral reef fish community dominating Darvel Bay as having undergone a rapid shift in structure following intense and rampant fishing pressure, as reported by the media.