Volunteers in Con Dao and scientists transplant coral corals on the natural bottom. Photo: VNA broadcast Master Nguyen Cong Danh, Director of the Department of Science and Technology of Ba Ria – Vung Tau province, Chairman of the Advisory Council evaluating and accepting the project implementation results, chaired the meeting. The waters of Con Dao have marine biodiversity among the first in Vietnam with coral reefs playing an important role. Recent research shows that many Con Dao coral reefs have recovered quite well after being degraded. However, some reefs cannot recover from degradation or have narrow areas due to the lack of hard bottoms for coral growth. Therefore, the issue of restoring hard corals was proposed by Con Dao National Park and approved by the People’s Committee of Ba Ria – Vung Tau province. The Management Board of Con Dao National Park has cooperated with Nha Trang Institute of Oceanography to implement the project “Selection of applied models of hard coral recovery in ramsar area of ​​Con Dao National Park”. The project is implemented from May 2018 to April 2021 to restore and regenerate coral reefs affected by natural disasters but cannot restore naturally. The project has a common goal of restoring and managing a number of coral reefs in the ramsar area of ​​Con Dao National Park with community participation with 2 specific objectives: assessment of resilience and management of the reef. Ramsar Coral Park Con Dao National Park on the basis of coral reef status analysis and application of restoration techniques; building models of planting and restoring coral reefs in ramsar area of ​​Con Dao National Park (scale of 3 ha) and managing coral reef ecosystems to regenerate aquatic resources, protect the environment, and serve tourism. marine ecology. The project has 6 identified contents, including site selection survey, determining the scale of hard corals restoration in the ramsar area of ​​Con Dao National Park; assess the current status of coral reefs in the selected area before and after the rehabilitation, building a set of criteria for evaluating the restoration results; train community awareness on conservation and training skills in coral reef restoration for local officials and communities. The project also restored reefs on natural bottoms and artificial victim modeling; monitor and supervise the trend of change, the development ability of the recovered corals, the biological resources at the recovery location; building procedures for restoration, scale for the care and protection of hard corals. The members participating in the project to install iron piles as a permanent support for corals on the natural bottom. Photo: VNA broadcast Deputy Director of Con Dao National Park Tran Dinh Hue said, based on the survey results, the implementation team has chosen the method of restoring corals on the natural bottom (which used to be coral but degraded) and artificial bottom (previously no corals). On an artificial bottom, corals were recovered by group fragmentation according to Heeger & Sotto and Edwards’ recovery instructions. For an artificial substrate, the coral groups are fixed on an arched concrete platform with a diameter of 100x60cm (2 bottoms), 80cm high, 5cm thick, with 8-10 holes (10 – 15 cm) to increase coral immobilization and facilitate habitat entry. The total number of concrete tanks as artificial substrates in this project is 150 tanks. For natural substrates, coral conglomerate fragments are fixed directly on dead corals by wire or drawstring. To create strength, use iron stakes or steel nails mounted on the dead coral foundation as a permanent support for the coral. The average distance between colonies is about 0.50 – 1 meter with the way that the corals are vertically oriented and the most contact with the substrate is dead coral or iron piles. In addition, the “transplanted” coral branches are tagged to facilitate periodic inspection. Seven corals of three genera Acropora, Montipora, Pocillopora and two families Acroporidae and Pocilloporidae were selected for restoration. A detailed assessment of the current bottom status of the coral restoration area after restoration in September 2020 shows that the average coverage of hard corals at 3 points of Bai Cat Lon, Hon Tai, Dat Doc increased from 1. , 5 to 12%. This proves that restoring hard corals in degraded reef areas or creating coral recovery media on the bottom both creates conditions for the growth of corals and landscaping for living creatures. According to the assessment, in September 2020, the average density of coral reefs in the coral rehabilitation areas in Con Dao ranged from 175 to 752 individuals / 100 m2. The project has achieved its overall goal of restoring and managing a number of hard coral reefs in Con Dao National Park ramsar with community participation. During the period from October 2018 to September 2020, the project organized 5 rounds of hard coral assessment and restoration in 3 areas, including Dat Doc, Southwest Hon Tai and Bai Cat Lon. A total of over 6,000 pieces of the coral group were relocated and fixed on an area of ​​3 hectares, 1 hectare each. For corals recovered on natural bottoms in Dat Doc and southwest of Hon Tai (over 4,400 groups), the average survival rate of 5 recovered corals including Acropora grandis, Acropora hyacinthus, Acropora robusta, Acropora millepora and Acropora formosa are 82.1% and 82.9%, respectively. Meanwhile, the artificial bottom restoration of concrete tanks (over 1,600 groups) had a higher survival rate (85.6% for the 3 species of Acropora grandis, Acropora robusta and Acropora formosa). Some hard corals of beautiful shapes and colors also provide 100% survival. The average monthly growth rates of the three species of Acropora formosa, Acropora robusta and Acropora grandis in Dat Doc were 0.82cm, 0.89cm and 0.5cm, respectively. For the Hon Tai area, the average monthly growth rates of these three species are 0.81cm, 0.62cm and 0.47cm, respectively. On the artificial substrate, the average growth rate of Acropora formosa was higher than that of Acropora grandis with 0.88 cm / month and 0.74 cm / month, respectively. These values ​​indicate that the recovered branch corals in Con Dao were well developed. Volunteers in Con Dao and scientists transplant coral corals on the natural bottom. Photo: VNA broadcast According to Associate Professor, Dr. Vo Si Tuan, Director of Nha Trang Institute of Oceanography, Con Dao coral suffers many disasters, but fortunately, the natural regeneration of the coral reefs is very good, the coral cover is high. . In the near future, Con Dao National Park needs to strengthen the management of coral reefs, establish coral conservation zones to create conditions for marine life to live, develop and spread to the natural environment; mobilize by means of socialization of tourism businesses for the community to join hands in both exploiting aquatic resources and protecting, cultivating and exploiting aquatic products in a sustainable manner. The project has contributed to improving 3 reef areas, increasing coral coverage, increasing sustainable attachment prices for regenerating corals and creating a stable environment for development of the reef biome. The project has met the most basic criteria to evaluate the effectiveness of restorative corals including: survival rate, growth rate of coral colonies and habitat characteristics of the rehabilitation zone such as change. changes in the coverage of the benthic components, the emergence of species of economic and ecological value, an increase in density as well as the size of the reef biome. Through training and hands-on training, the project has supported Con Dao National Park to improve capacity and from now on Con Dao National Park Management Board can organize hard coral restoration with on-site human resources. employees and partners from the local community. After the meeting, the Advisory Council assessed, accepted and accepted the satisfactory evaluation of the project “Selecting the application model of hard corals recovery at ramsar, Con Dao National Park” with the consensus of all all 9 out of 9 scientific members join the Council. After transferring the project to the beneficiary of Con Dao National Park, the authorities encourage businesses to join the management of coral reef restoration for tourism, creating Artificial reefs in deep sea areas to develop adventure tourism.

With the People’s Committee of Da Nang City in principle agreeing to the Vietnam Maritime Administration (Ministry of Transport) to research, survey and implement procedures for submerging 200,000 m3 of material in the sea of ​​Da Nang, experts say. There is a need for a careful assessment of the environmental impact (EIA).

Danang’s marine ecosystem is in decline

Associate Professor-Dr. Vo Van Minh, Chairman of the Council of Da Nang Pedagogical University, said that if there is no other dumping site, there is only way to sink into the sea. However, where to sink, in EIA techniques, it is necessary to determine which sea is the safest, least damaging to the environment.

“Currently, the waters of Danang are not included in the group of protected areas, so it can be submerged. However, from an environmental perspective, falling there will certainly affect immediately, especially coral reefs and seagrass areas. These areas are very important for their habitat and breeding grounds for marine life. Surely it will disturb the environment, affect species of marine fauna and flora “- Mr. Minh said.

Mr. Minh emphasized that in the EIA technique, it is only said to minimize to the lowest level, in the permitted level, not say that it is not impacting. Da Nang’s marine ecosystem is in decline, especially the coral system due to poor conservation, tourism and wastewater impacts.

“I want the EIAs to consult with scientists, but if they do not do well, it is dangerous for the environment” – Mr. Minh worried.

According to Dr. Nguyen Tac An, former Director of Nha Trang Institute of Oceanography, in order to carefully analyze the EIA capacity of submerging, it is necessary to understand the dredging method and the submerged technique. It can be said that all the material in the sea when lying still is okay, but when touched and bounced, many problems occurred. Therefore, it is okay to say just taking this place and leaving that place.

Mr. An said that the submergence principle must stay away from sensitive areas such as residential areas, fishing grounds, protected areas and special values ​​of the sea. In addition, when submerged, it is necessary to avoid seas with strong motivations.

“Actually we dumped it, but it will run away. Submerging techniques must be very attentive. Must see if the quality of sediment and chemicals in the area we scraped up is toxic or not. This EIA agency is aware of both. The dynamic maps in Vietnam nowadays all have them. Therefore, when pouring, it must be considered and calculated. The EIA agency will have to take physical samples for testing, calculate the propagation pattern, size, dredging and dredging time “- Mr. An noted.

Mr. An emphasized: Dredging the sea channel is very important for economic development. Dredging cannot be helped. However, how to minimize the impact of the dredger to increase the overall economic value.

Experts believe that when evaluating the EIA, it is necessary to determine which sea area is safe, with the least damage to the environment. Photo: LE PHI

Dredging the sea channel into Tien Sa port will create 200,000 m3 of material and be calculated to submerge in the waters of Da Nang. Photo: TAN VIET

Worry about coral reefs

Talking about the material submerged in Da Nang sea, Dr. Nguyen Thi Minh Phuong, Dean of the Faculty of Environment – Chemical Technology (Duy Tan University), assessed that 200,000 m3 of material is much and will definitely affect the system. marine ecology.

“The affirmation is always going to impact the ecosystem. When we poured like that, we thought it would lie there, but in fact it was not there at all, it had extremely large currents, so it would be swept away. Must see under that sea there are corals or not, because the most fear is the influence of the coral. When pouring like that, the coral cannot withstand the mud, when the water is too turbid, the symbiotic algae of the coral dies and makes the entire coral carpet die “- Ms. Phuong said.

Ms. Phuong further analyzed the great possibility that the sea area is expected to be submerged deep enough that there are no live corals. Most worrying, however, is that the currents will sweep matter around. Especially sediments, if heavy sediments will be deposited, and fine-grained sediments will be swept away.

“Saying a 100-hectare sea area, it will actually wash away very far. The sediment in the dredging site is likely to be fine-grained, not coarse-grained sediment. Fine means it is light, can be washed away, coarse grain is deposited in place and moves slowly. In a period of a few years it will be swept away everywhere and swept seasonally, because the flow changes with the seasons. Wherever the flow is, the coral will die there. The symbiotic algae of the coral needs light, the coral ecosystem is extremely important. And the bottom ecosystem will be temporarily destroyed for a while, then recover “- Ms. Phuong said.

Ms. Phuong added that from a management perspective, any project will have an impact on the environment. If you consider the environmental impact less than the likelihood of economic development, that’s okay, it’s worth the tradeoff.

“Also saying no effect is not right. The impact at sea is difficult to control. If other ecosystems can recover over time, the corals will not, die will die ”- Ms. Phuong affirmed.

177 species of corals around Son Tra peninsula From 2016 to 2018, the Southern Institute of Ecology had the topic “Research on conservation and biodiversity restoration of terrestrial and underwater ecosystems in Son Tra Nature Reserve”. After nearly three years of restoration, the live coral cover increased by more than 10% compared to baseline. There is an increase in organisms living in the reef. The coverage of seagrass beds increases about 20% -30%. According to research by the Southern Institute of Ecology in 2019, the sea surrounding Son Tra peninsula has 177 species of coral belonging to 17 families and 52 varieties. There are also 130 species of fish living in coral reefs, belonging to 32 families and 65 varieties. This sea also has three species of seagrass distributed over a total area of ​​1 ha and 108 species of extremely diverse seaweed. However, the marine ecosystem here is seriously degraded.