What next for marine ecosystem management in Vietnam: assessment of coastal economy, climate change, and policy implication

Vietnam is a coastal country with a coastline stretching more than 3,260 km. Marine resources are important for the development of Vietnam. In Vietnamese seas, there are about 20 typical ecosystems spreading over 1 million square kilometers in the East Sea consisting of mangrove forests, coral reefs, lagoons, seagrasses in intertidal areas and estuaries, and living species in 155,000 hectares, 1,300 square kilometers, 500 square kilometers, 16,000 hectares, and 11,000 living species, respectively. At present, the impact of climate change, socio-economic development, and environmental pollution are considered as the main causes of degradation of Vietnam’s marine ecosystems. This paper presents and discusses the pressure of socio-economic activities including industry, tourism, marine transportation and services, aquaculture and fishery on marine ecosystems. In Vietnam, compared to the early 2000s a total of 12% of coral reefs, and 48% of other coral reefs are vulnerable to degradation. So far, about 100 species of marine life in Vietnam are at risk of being threatened due to over-exploitation and fishing. The seagrass-bed ecosystem is currently being degraded with only over 5,580 ha remaining. In some areas, such as Cat Ba, Ha Long, and Quang Nam, seagrass beds have almost no chance to recover naturally due to serious impacts from tourism and aquaculture activities. From the findings, orientations that aim at effective management and protection of marine ecosystems to cope with adverse impacts of anthropogenic activities, climate change, and the pressure of socioeconomic development were proposed.


Introduction
Marine ecosystem covers more than two-thirds of the Earth's surface consisting of more than 97% and 90% of the Earth's water supply and habitable areas on the planet, respectively (Fava 2022).Besides, other benefits, marine ecosystems also provide socioeconomic incentives through tourism, fishing and aquaculture, offshore oil and gas, trade, and transportation (Kingsford 2023).
Vietnam's coastline is more than 3,260 km consisting of over 3,000 large and small coastal islands and two archipelagos of Hoang Sa and Truong Sa which represents Vietnam's exclusive economic zone is over one million square kilometers.Vietnam's waters have about 20 types of marine ecosystems.Typical marine ecosystems in the coastal zone include tidal flats, estuarine seagrass beds mangroves, coral reefs, lagoons, bays, aquatic ecosystems within, around and of coastal and offshore islands, including deep seabed.
The sea and marine ecosystems have been contributing to the economic and social development of Vietnam as well as of the coastal provinces, with almost 50% of Vietnam's GDP, in which the marine economy's contribution stands to one-fifth of the total GDP.In the period 2016-2019, gross domestic product in coastal localities grew on average 7.5% per year which was higher than the national average of 6%, of which the main

Methodology
The present study is developed from an extensive review of the literature with the main focus on Vietnam's marine ecosystem, coastal economy, coral, and government policies on marine environment management.A number of surveys have been conducted in some sea areas of Vietnam including Quang Ninh, Nha Trang, Vung Tau, and Quang Ngai in order to have a visual view and assess the current status of coastal marine ecosystems, especially coral reefs.In addition, changes in sea surface water temperature during 1901-2020 were taken from the National Oceanic and Atmospheric Administration database (NOAA 2021 and2022).
The pressure of socioeconomic development on marine ecosystems and the current status of marine ecosystems were then discussed.Finally, based on strategic analyses of the legal system, policy, and institutional framework of the current marine environment management systems of Vietnam, orientations that aim at effective management and protection of marine ecosystems coping with adverse impacts of future climate change and the pressure of socioeconomic development were proposed.

Results and discussion
3.1.Pressure from coastal socio-economic development 3.1.1.Pressure from population growth and urbanization In Vietnam, there are 28 coastal provinces and cities covering 51 million inhabitants with an average population density of 1.9 times higher than the national average.In those 28 provinces, there are 125 coastal and island districts each covering a total population of 18 million people with a density of 354 people/km 2 .Along with urbanization, the consumption demand of people has increased, which means an increase in waste generation, putting pressure on the environment.Besides, the promotion of marine economic sectors has also been putting pressure on the water environment and marine sediments in coastal areas (MONRE 2021, Pham 2021).Some key demographic, geographic, and economic indicators of Vietnam are presented in figure 1.
As for domestic wastewater generation in coastal cities, it is estimated that the amount of water emitted is about 122-163 million m 3 /day.Meanwhile, the amount of per capita solid waste generated in urban areas is 1.08kg/person/day, and in rural areas is 0.45, of which 28 coastal provinces and cities contribution in 2019 was as much as 74%, leaving about 26% of the waste untreated.For inhabited islands, the amount of waste generated is mainly from domestic waste, tourism, and anchorage areas of boats and coastal fishing villages.In large islands, some waste has been collected, but in small islands, these activities have not been implemented much (MONRE 2021, Pham 2021).Table 1 presents the amount of domestic wastewater in major coastal cities of Vietnam.
3.1.2.Tourism and marine services create direct pressure on the marine environment Presently, 70% of tourist areas and attractions in Vietnam are concentrated in the coastal strip.Along with the increase in the number of visitors, there is considerable pressure on urban infrastructure, and water supply and sewerage systems.The amount of solid waste generated from cruise ships in the Gulf of Tonkin alone is 11.3 kg vessel day −1 and night.In addition, there is wastewater from bathrooms and kitchens with dirt, food, grease, etc Water containing oil on ships also puts great pressure on the marine ecosystem.Currently, the most used treatment method is separation/settlement and then discharge into the bay (77%) while only 20% of wastewater is brought to shore for treatment.
Sea transportation is an important form of transportation for a wide range of chemicals including hazardous and toxic chemicals.These chemicals, if leaked into the marine environment, are dangerous to aquatic and human health.In Vietnam, about 2000 chemicals are regularly transported by sea, and 10%-15% of the oil released at sea comes from oil tanker accidents.The chemical composition of the oil changes complexly after it is released into the environment.

Port activities
Dredging activities of port channels lead to increased turbidity, changes in hydrographic regime, and pollutes seabed sediments.The process of loading and unloading goods causes the release of pollutants such as oil, grease, metal ores, fertilizers, toxic gases, dust, etc, causing odor pollution, and reducing the clarity of the water.In   2 as the total oil and grease content in seawater at all the observed sites was far beyond the standard line.

Pressure from industrial activities
Currently, Vietnam has over 400 industrial zones established inside and outside the coastal economic zone.
Besides the amount of wastewater discharged from the industrial zones, wastewater are also discharged from small industrial clusters, with an average of 15-20 m 3 of wastewater/ha/day and night.By the end of 2020, the country has 730 industrial clusters with an area of 22,336 hectares put into operation, attracting nearly 12,000 investment projects.However, besides some industrial clusters that have measures to protect the environment with centralized wastewater treatment systems (accounting for 19.3%) and automatic wastewater monitoring systems (accounting for 21.7%), there are many clusters with no environmental protection measures.According to statistics from environmental protection reports of 16 coastal provinces, there are more than 7,600,000 m 3 / day and night of wastewater from establishments with a wastewater volume of 1,000 m3 / day and night being discharged into the environment (MONRE 2021, Pham 2021).
3.1.5.Pressure from aquaculture and fishery Vietnam's aquaculture ranks fourth in the world both in volume and value.It also holds the third place as an exporter of fisheries products (Hedberg et al 2017).The total potential aquaculture area of Vietnam is about 244,190 ha, of which the coastal intertidal area is 153,300 ha, accounting for 62%; farming area in the bay, along the island is 79,900 ha, accounting for 33% (MONRE 2021).
Coastal aquaculture is a direct source of waste to the marine environment.The aquaculture area at sea is concentrated on closed bays, coastal tidal flats, and a part of islands and open seas.The main waste from aquaculture is sludge and wastewater in very large amounts.According to data from the Directorate of Fisheries, in the period 2015-2018, the amount of both sludge and wastewater from shrimp and pangasius farming, which are major aquacultural products in Vietnam, increased rapidly (table 2).During aquaculture, farmers use growth stimulants, antibiotics, and anti-scale agents.These substances can be toxic to some other species as well as the ecosystem.According to Wu (1995), sea cage aquaculture is a point source of pollution consisting of dissolved nutrients, feces, feed fragments, chemicals, and diseases.The main environmental problems are thus associated with eutrophication which is harmful to coral reefs (Fabricius 2011, Weber et al 2012, Hedberg et al 2015).The sludge in the aquaculture process contains rotten, decomposed residues of food, chemicals, and antibioticsK This layer of sludge has a thickness of 0.1 − 0.3 m in the flooded state.Rare gases will decompose into many toxic substances such as H 2 S, NH 3 , and Methane.
The construction of aquaculture ponds in estuaries and coastal areas can lead to changes in biome habitats, salinity, sedimentation, and coastal erosion.Moreover, in farming areas, the indiscriminate discharge of eutrophic organic substances, biological toxins, and domestic wastes causes environmental degradation, and outbreaks of diseases, and causes significant economic losses as well as environmental conditions (MONRE 2021, Pham 2021, Hoang et al 2022).
Ships engaged in marine fishing are also a source of emissions such as oil and grease leaks from marine engines, nets, old broken fishing gear, ship washing water, and domestic waste, etc 3.1.6.Pressure from ocean plastic waste More than 80% of annual ocean plastic waste originates from land, of which the majority is large-size plastic waste.The rest is plastic waste discharged directly into the sea, mainly from fishing activities.The marine floating plastics are mostly polyethylene and polypropylene which are difficult to decompose like other types of waste (Danh and Hoi 2019).
On average, each square kilometer of the world's ocean surface contains 13,000 to 18,000 pieces of plastic waste of which 70% of plastic waste is expected to sink to the seabed (MONRE 2021, Pham 2021).
Vietnam was reported to rank the 4th in the world (after China, Indonesia, and the Philippines) in terms of the amount of mismanaged plastic waste with 1.83 million tons per year that accounts for 5.8% of global mismanaged plastic waste (Tibbetts 2015, Jambeck et al 2015).The situation of plastic waste pollution in Vietnam's sea can be seen in figure 3.According to MONRE (2021) and UNDP (2022), in 2018, plastic waste dumped along the coastal areas and in the sea in Vietnam ranged from 0.28 to 0.73 million tons/year, equivalent to 6% of the total amount of plastic waste discharged into the sea, making Vietnam as one of the leading countries in the world with the largest amount plastic waste in the marine ecosystem.Plastic waste, together with wastewater, UV chemicals, coastal runoff, and other types of wastes released to the sea has caused various damages like degradation of coral reefs, damage to the seagrass, turbidity, and other chemical and aesthetic pollution in coastal areas (Todd et al 2010, Bijeesh et al 2023).

Climate change and challenges
Climate change is one of the causes of changes in physical, chemical, and biological environmental indicators of the sea and ocean.Rising temperatures, sea level rise, and changing rainfall make ecosystems, fisheries, infrastructure, and livelihoods vulnerable.
According to IPCC (2013), sea surface temperature increased during the 20th century with an average rate of 0.14°F per decade and is continuously rising.The El-Nino phenomenon has increased both the frequency and intensity and that has led to a rise in sea temperature, and insolation beyond the tolerance of corals, making them white, which science calls coral bleaching.Not only coral ecosystems are heavily affected, but seagrass ecosystems are also seriously affected by negative manifestations of climate change.Climate change has also increased the trend of ocean acidification and tropical storms both of which have destructed coral reefs and seagrass beds (CESTI 2016, Gissi et al 2021, Lincoln et al 2022, Pentz and Klenk 2023).
Scientists warn that when the sea level rises, the water salinity in mangroves can exceed 25%, leading to the extinction of some species of mangroves.If the amount of sediment in the mangrove area does not exceed sea level rise, the length of time the roots are submerged will increase and some plants that cannot withstand longterm flooding will die (Gissi et al 2021, Lincoln et al 2022, Pentz and Klenk 2023).
According to the annual assessment on the countries most affected by extreme weather events in the period 1997-2016, Vietnam was ranked 5th in the Global Climate Risk Index in 2018 and 8th in the Long-term Global Climate Risk Index (Eckstein et al 2018).
Extreme weather events, including frequency and duration of rainfall and the time-series evolution of climate change in Vietnam is increasing in frequency, but is yet difficult to predict accurately.The highest monthly rainfall increased from 270 mm in 1901-1930 to 281 mm in 1991-2015, and the highest monthly temperature increased from 27.1 °C (1901-1930) to 27.5 °C (1991-2015).
Sea level rise is also one of the typical manifestations of climate change in Vietnam.The data of Hon Dau national station recorded within 50 years shows that the sea level rises about 20 cm.The observed sea level at the hydrographic stations reached 2.45 mm year −1 and 3.34 mm year −1 respectively in the periods 1960-2014 and 1993-2014.Satellite data shows that in the period 1993-2018: The average water level of the whole East Sea increased by 4.1 mm year −1 .The average water level in the coastal area of Vietnam increases by 3.6 mm year −1 (MONRE 2020).
According to Climate Change and Sea Level Rise Scenario for Vietnam (MONRE 2020), the average annual temperature nationwide in the middle of the 21st century could increase to 2.3 °C, by the end of the century, the highest increase could reach 4.2 °C.By the end of the 21 st century, sea level rise in the East Sea area under the RCP8.5 scenario is about 77 cm (51 cm-106 cm) (table 3).The central area of the East Sea (including Hoang Sa and Truong Sa archipelagoes) has a significantly higher sea level rise than other areas.
The above forecasts about climate change and sea level rise in Vietnam show that Vietnam's marine ecosystem and environment will face great challenges, requiring actions and suitable mitigation and adaptation measures.3.3.Current status of Vietnam's marine ecosystems Vietnam is a coastal country with a coastline stretching in excess of 3,260km.Marine resources are important for the development of Vietnam.In the Vietnamese seas, there are about 20 typical ecosystems spreading over 1 million square kilometers in the East Sea consisting of mangrove forests, coral reefs, lagoons, seagrasses in intertidal areas and estuaries, and living species in 155,000 hectares, 1,300 square kilometers, 500 square kilometers, 16,000 hectares, and 11,000 living species, respectively.This includes approximately 6,000 benthic species; 2,038 fish species, 653 species of seaweed, 657 species of zooplankton, 537 species of phytoplankton, 94 species of mangroves, 225 marine shrimp species, 14 species of seagrass, 15 species of sea snakes, 12 species of marine mammals, 5 species of sea turtles and 43 species of water birds (MONRE 2015, CESTI 2016).
Coral reefs are one of the unique ecosystems of Vietnam's sea that support valuable ecosystem goods including marine products and services such as fisheries habitat, tourism, and coastal protection (Quach 2018).Coral reefs have very high biodiversity, interesting landscapes, and are widely distributed from North to South.The diversity and abundance of Vietnamese coral are reflected in 350 reef-forming species and about 3,000 other organisms with an attached life related to coral reefs, including many species with high economic value such as lobster, abalone, pearl mussel, and sea cucumber.The total valuation in USD of the economic and ecosystem services provided by Vietnam's coral reef ecosystem is estimated at about 100 million/year, of which 1 km 2 of coral reefs can provide the amount of seafood caught up to 10,000 USD.In the Mekong Delta, 1 km 2 of mangroves can provide a catch of 450 kg of seafood.Each year, the seagrass ecosystem provides aquatic products and services worth more than 20 million USD and the value that the lagoon brings is estimated at over 2,000 USD/ha.In addition to the economic and tourism values, coral reefs in some places also have regulatory value, and are an effective tool for coastal protection, marine biodiversity conservation, and fisheries management (Quach 2018, Nguyen andDoan 2021).
More than one-third of the population of Vietnam lives in coastal regions, making it a coastal nation.About half of the nation's gross domestic product (GDP) is made up of the economies of the sea, coastal cities, and provinces, with the marine economy alone accounting for 20 to 22 percent.However, habitat fragmentation, degradation, loss, overfishing and other forms of overexploitation, climate change, and pollution, particularly marine litter, pose a threat to Viet Nam's ocean health.Coral reefs in Vietnam are suffering from degradation and a sharp population decline.
According to the National Report on the Maritime and Insular Environment in the 2016 − 2020 period (MONRE 2021), about 40 percent to 60 percent of seagrasses in the entire sea area of Vietnam from Quang Ninh to Ha Tien have been lost.In addition, the lost Mangrove forests and coral reefs accounted for 70 percent and 11 percent, respectively.With the complete destruction of primary mangrove forests, there is a decline in overall mangrove area and has led to the decline of marine biodiversity, breeding grounds, overall aquatic species, and seagrass-bed ecosystem.
The degradation of seagrass beds has resulted in the reduction of the number of individuals and overall aquatic species thus constraining distribution area, pollution, habitat degradation, and reducing biodiversity and economic benefit of endangered species.Seagrass beds are distributed from the North to the South and around the islands, at a depth of 0 − 20 m.Currently, only about over 5,580 ha of seagrass remain.In some areas, such as Cat Ba, Ha Long, Quang Nam, etc seagrass beds have almost no chance to recover naturally due to serious impacts from tourism and aquaculture activities (Nguyen andDoan 2021, Nguyen et al 2022).
In Vietnam, since the early 2000s a total of 12% of coral reefs, and 48% of other coral reefs are vulnerable to degradation.So far, about 100 species of marine life in Vietnam are at risk of being threatened due to overexploitation and fishing.The seagrass-bed ecosystem is currently being degraded with only over 5,580 ha remaining.In some areas, such as Cat Ba, Ha Long, and Quang Nam, seagrass beds have almost no chance to recover naturally due to serious impacts from tourism and aquaculture activities.The area of coral reefs lost is concentrated mainly in inhabited areas such as Ha Long Bay, the central coastal provinces, and some inhabited islands of the Truong Sa archipelago, with many areas losing more than 30% of coral cover (Khanal et al 2021, MONRE 2021, VACNE 2022).Figure 4 shows coral reef bleaching heat stress globally watched by NOAA. Figure 5 presents the degradation and death of corals surrounding Hon Mun Island, a popular spot for corals in Nha Trang Bay of Vietnam.
The decline and damage to many coral reefs reduce biodiversity, ecology and marine environmental quality and have affected tourism, fisheries, and the livelihoods of coastal communities (Börger et al 2021).Currently, although Vietnam has successfully planted and restored corals in the wild, the area restored is still very low.
Researchers have so far recorded about 100 species of marine life in Vietnam that are at risk of being threatened due to over-exploitation and fishing.These are rare species and have been included in the Vietnam Red Book and IUCN Red List to require protection measures (including 37 species of marine fish, 6 species of coral, 5 species of echinoderms, 4 species of spiny lobster, 1 species of sam, 21 species of snail, 6 species of bivalve, 3 species of squid) (MONRE 2021).Research showed that more than 80% of fish in Vietnam's coastal and offshore waters have been exploited, including up to 25% of the fish is over-exploited or depleted, and many other marine species are in danger of extinction (JICA 2013, FAO 2020, MONRE 2021).

Legal system and policy on marine environment protection
Up to the present, Vietnam has promulgated many important laws regulating the protection and rational use of natural resources and pollution control, creating an important legal basis for marine environment protection activities in general and the protection of marine ecosystems in particular.In addition to the 2013 Constitution, the basic law defining the constitutional principles of environmental protection including the marine environment, a number of laws directly or indirectly regulating the protection of the marine environment have been promulgated.Important laws in this area include the Law on Environmental Protection 2014, the Law of the Sea of Vietnam 2012, the Law on Water Resources 2012, the Law on Fisheries 2003, the Law on Biodiversity 2008, the Law on Forest Protection and Development 2004, Law on Atomic Energy 2008, Law on Petroleum 1993(amended and supplemented in 2000and 2008), Maritime Code 2015, and Law on natural resources and environment of sea and islands 2015.Among these laws, the Law on Environmental Protection acts as a framework law, defining the general principles of marine environment protection and especially emphasizing the principle of sustainable development in environmental protection.
This system of legal documents, on the one hand, helps Vietnam fulfill its international legal obligations on marine environment protection, on the other hand, prescribes specific actions and measures to protect the marine environment of the country.In principle, the provisions of Vietnamese law in this field have approached modern perspectives in the management and protection of biodiversity and marine biological resources through a system of regulations on methods of integrated management in the exploitation, use, and protection of marine resources as well as the control of marine environmental pollution.For example, any organizations or individuals that may pollute, deplete natural resources and degrade marine biodiversity are to be handled by laws, and possess liability for the remedy, restoration, and compensation for damage.The content of the principle has been recognized in Article 63 of the 2013 Constitution.
Along with laws and regulations, Vietnam also issued marine-related strategies.Resolution 03-NQ/TW, adopted in 1993 by the Party Central Committee's Political Bureau, which can be considered as the first major marine strategy of Vietnam, set the goal of turning Vietnam into a strong marine economy.Then, Resolution 09-NQ/TW on the Vietnam Marine Strategy through 2020 (the Marine Strategy) adopted in 2007, aimed to make Vietnam a 'strong marine economy' by 'bringing into play all potentials from the seas' (Nguyen 2022).The Strategy for sustainable development of Vietnam's marine economy to 2030 with a vision to 2045 identifies 'making Vietnam a strong maritime nation; basically meet the criteria for sustainable development of the marine economy; formation of marine ecological culture; proactively adapt to climate change and sea level rise; prevent the trend of pollution, degradation of the marine environment, coastal erosion and sea erosion; restore and conserve important marine ecosystems.New, advanced, and modern scientific achievements have become direct factors in promoting sustainable development of the marine economy' (Party Central Committee 2018).
The Strategy on exploitation and environmental protection of sea and islands by 2030, with a vision to 2050 sets a general goal by 2030 that sea and island resources are rationally exploited, effectively used to serve socioeconomic development in association with ensuring national defense and security, foreign affairs and international cooperation; pollution of the marine environment is prevented, controlled and significantly reduced; marine, coastal and island biodiversity is protected, maintained and restored; the values of natural heritage and marine cultural heritage are preserved and promoted; The impact of natural disasters is minimized as much as possible, proactively and effectively responding to climate change and sea level rise, aiming to turn Vietnam into a rich and strong marine country.One of the important goals of this strategy is 'well manage and protect marine, coastal and island ecosystems, increase the area of marine conservation zones and preserved marine and coastal areas to at least 6% of the natural area of the national sea area; breeding areas, areas where young aquatic species live, habitats of aquatic species, migration routes of aquatic species, biosphere reserves, RAMSAR sites; restore the coastal mangrove area to at least 2000 levels; effectively respond to natural disasters, climate change and sea level rise based on sustainable use of resources and protection of sea and island environment along with strengthening capacity to forecast and warn of natural disasters and climate change and effects of sea level rise (Vietnam Government 2023).
Along with building an internal legal system and strategies, Vietnam has carried out many international cooperation activities related to marine resources and the environment.Vietnam has promoted negotiations for the settlement of sea disputes and signed three agreements on delimitation and two others on joint exploitation in maritime zones, thus facilitating the establishment of maritime zones under the United Nations Convention on the Law of the Sea (UNCLOS) for the implementation of its Marine Strategy.Vietnam has also succeeded in applying the integrated management approach to its maritime zones and actively participated in programs of the Partnerships in Environmental Management for the Seas of East Asia (PEMSEA), the United Nations Environment Program (UNEP), the International Union for Conservation of Nature (IUCN), and other regional organizations.So far, 14 out of the 28 coastal provinces and cities have developed their strategies for integrated coastal zone management (Nguyen 2022).
In general, the legal system, strategies, and policies on management and protection of the marine environment though seem timely and complete, but need to be strengthened and implementation should be strictly regulated.However, the current degradation of marine ecosystems implies that Vietnam lacks an effective legal mechanism to control activities that affect nature and affect the marine environment.Sanctions are not appropriate and not strong enough to punish and deter violations.

Conclusions and recommendations
The specific conclusion based on this study is outlined as below, • In Vietnam, the increase in population, and unplanned coastal development have led to an increase in wastewater generation to as much as 122-163 million m3/day, and per capita solid waste generated has been 1.08kg/person/day in urban areas and, 0.45 kg/person/day in rural areas, • The amount of solid waste generated from cruise ships in the Gulf of Tonkin alone is 11.3 kg vessel day −1 .
• The most commonly employed method of wastewater treatment is sedimentation (77%) and discharge into the bay.Only 20% of wastewater is taken for the treatment.
• In Vietnam, about 2000 chemicals are regularly transported by sea, and 10%-15% of the oil released at sea comes from oil tanker accidents.
• Vietnam has over 377 industrial zones and 730 industrial clusters with an area of 22,336 hectares put into operation, attracting nearly 12,000 investment projects of which only 41% of wastewater generated is being treated.
• The sludge in the aquaculture process has a thickness of 0.1-0.3m in the flooded state and is detrimental to aquatic health containing toxic gases like H2S, NH3, and CH4.
• In Vietnam, more than 80% of annual ocean plastic waste originates from land, of which the majority is largesize plastic waste.In 2018, plastic waste dumped along the coastal areas and in the sea in Vietnam ranged from 0.28 to 0.73 million tons/year, equivalent to 6% of the total amount of plastic waste discharged into the sea.
• Climate change predictions show that, the average annual temperature nationwide in the middle of the 21st century could increase to 2.3 °C, by the end of the century, the highest increase could reach 4.2 °C.By the end of the 21st century, sea level rise in the East Sea area under the RCP8.5 scenario is about 77cm (51 cm to 106 cm).
• The diversity and abundance of Vietnamese coral are reflected in 350 reef-forming species and about 3,000 other organisms with an attached life related to coral reefs, including many species with high economic value such as lobster, abalone, pearl mussel, and sea cucumber.
• About 40 percent to 60 percent of seagrasses in the entire sea area of Vietnam from Quang Ninh to Ha Tien has been lost.In addition, the lost Mangrove forests and coral reefs accounted for 70 percent and 11 percent, respectively.
• In Vietnam, since the early 2000s a total of 12% of coral reefs, and 48% of other coral reefs are vulnerable to degradation.So far, about 100 species of marine life in Vietnam are at risk of being threatened due to overexploitation and fishing.The seagrass-bed ecosystem is currently being degraded with only over 5,580 ha remaining.The area of coral reefs lost is concentrated mainly in inhabited areas such as Ha Long Bay, the central coastal provinces, and some inhabited islands of the Truong Sa archipelago, with many areas losing more than 30% of coral cover.
• So far about 100 species of marine life in Vietnam are at risk of being threatened due to over-exploitation and fishing.
Currently, under the pressure of rapid population growth and socio-economic development, in the context that natural resources from the mainland are gradually being exhausted, the trend of going to the sea, expanding the boundary to the sea, and exploiting the sea is increasingly being intensified.However, it is accompanied by unsustainable exploitation methods, disregarding environmental protection, without or lack of detailed and specific plans, along with a weak management mechanism that has led to the pollution and degradation of the marine environment.In particular, in the context of the impact of climate change with temperature increase and sea level rise, the problem of resource exploitation and marine environment protection in Vietnam is increasingly facing many challenges, posing negative impacts on socio-economic development.
Even though Vietnam has laws and regulations to manage coastal ecosystems and coral reefs, effective implementation of the law, surveillance and regular monitoring, and provisioning of rewards and penalties could restore and manage coastal ecosystem services more effectively.In order to strengthen and improve the efficiency of natural resource management and protection of the marine environment and marine ecosystems, Vietnam needs to continue to improve the legal system on natural resource management and marine environmental protection, in which strong sanctions should be introduced for acts that harm the marine environment; actively strengthen and expand international cooperation in management and research on resources and environment of sea and islands; implementing the program on a basic survey of marine resources and the environment from which to build an information system and database of marine and national resources and environment; building a sustainable financial mechanism for the sustainable exploitation and use of marine resources; propagating and raising community awareness in the protection of natural resources and environment of sea and islands.

Figure 1 .
Figure 1.Key demographic, geographic, and economic indicators (Data source: General Statistics Office of Vietnam 2023).

Figure 2 .
Figure 2. Total oil and grease content in seawater at some major ports and beaches in northern Vietnam (Data source: Ministry of Natural Resource and Environment).

Figure 3 .
Figure 3. Solid and plastic waste pollution in coast and islands over Vietnam: a) Cai Chien Island in Quang Ninh Province in the North; b) Ly Son Island in Quang Ngai Province in the central region; c) Cam Ranh Bay in Khanh Hoa Province in the South central region; d) Vung Tau City in the South.Photos were taken during surveys conducted from 2020 to 2023.

Figure 4 .
Figure 4. Coral reef bleaching heat stress probabilities (a) and 60% probability coral bleaching heat stress for July-October 2022 (b) (source: adapted from NOAA 2022).Adapted from NOAA Coral Reef Watch, 2022.Image stated to be in public domain.

Figure 5 .
Figure 5. Underwater tourism activities (a), coral reef degradation (b and c), and dead corals (d) in Hon Mun island, Nha Trang Bay of Vietnam.

Table 1 .
Amount of domestic wastewater (m 3 /day) in major coastal cities.

Table 2 .
Amount of waste from aquaculture in Vietnam.

Table 3 .
Sea level rise scenarios for Vietnam.