Saving Vietnam's coral reefs

Although this is not the first time they have undertaken coral reef conservation and regeneration projects, this campaign, which started in May 2022 due to urgent degradation, is the very first attempt to save coral reefs that is supported by the community. Taking to social media, Sasa's team developed a fundraising campaign to seek the community’s support. After four months, they announced that the fund was raised and they planned to transplant a 40,000 metre-squared complex of coral reefs. 

Their final goal at the time was to replant 32 species of 18 important reef-building coral. The programme attempts to rebuild underwater coral nurseries, restoring a safe environment for ocean species.

Coral reefs are the most species-rich maritime ecosystem, accounting for roughly 32 percent of all listed marine species and 13 percent of unnamed marine species. They serve as biodiversity reservoirs by providing ecosystem services, goods, marine protection and a habitat for fisheries. Coral reefs also defend the coastline from natural disasters, like hurricanes, and improve the attractiveness of the underwater landscape. They also provide 60-70 percent of the oxygen reserves, which is higher than plants.

However, the distribution and value of coral reefs in Vietnam are still poorly understood. In 2014, there were no local volunteer and NGO-funded activities/programs for coral reefs, which is why the Sasa team is considered a rare voluntary group that works in coral conservation.

"The challenge is that restoration asks for the base of historical data and statistics," Le Chien, Sasa team’s founder, told FairPlanet. 

Looking for the best underwater approach to create coral nurseries, particularly during the most recent campaign, requires much investigation. “The process of assessing depth, light, environmental elements, nutrition, and especially not affecting the surrounding environment is the foundation of our success. Thanks to its unique construction, the nursery system was able to withstand the city's biggest storm in 30 years,” he recounted to FairPlanet. 

Da Nang’s corals in peril

Da Nang is known not only for its beaches, but also for its diverse fauna and flora habitat. The Son Tra peninsula is bounded to the northwest by Danang bay, which includes the Son Tra national nature reserve. 

The reserve is well known for having one of the country's most picturesque coral reefs with economic and natural potential. The coral diversity in Son Tra peninsula and Cu Lao Cham island of Hoi An city in the Quang Nam province was estimated to be higher than in other locations. According to a report from the Southern Institute of Ecology, a vast area from Hai Van Mountain to Son Tra Peninsula is home to 104 hectares of coral reefs, 26 hectares of seaweed and 10 hectares of sea-grass beds.

Unfortunately, due to significant consequences from natural and anthropogenic disturbances, its diversity could not be protected in the current global scenario. A study found that, globally, coral reefs have been reduced by half since the 1980s due to several reasons, such as rising pollution levels, unsustainable coastal development, overfishing, outbreaks of coral predators, anthropogenic ocean acidification and global warming. 

The sea’s rising surface-temperature is the primary cause of coral bleaching: even a temperature increase of only 1-2 degree Celsius above the average maximum for a region can trigger mass bleaching events. In Da Nang, major storms and super typhoons in 2020, 2021, 2022, or perhaps earlier have put the lives of coral reef systems in greater danger than ever before. The most recent storm, Noru, made a direct impact in October 2022, destroying more than 50 percent of the natural coral reefs in the reef at Bai But, Son Tra, according to the Sasa team. Coral reefs are fundamentally wave shields, however they are too fragile for high-grade storms or waves as tall as five to nine metres.  

In the grand scheme of things, land-based sediments and nutrients have become important threats to coral reefs in recent years. Increased river pollution, including highland silt run-off and domestic and industrial discharges, has aggravated the natural situation in many regions, posing a threat to the marine ecosystem.
 
In most of central and south Vietnamese cities, damaging fishing methods had caused heavy problems for coral reefs in the past. According to a report by the Sasa team after a one-year survey, coral reefs on the southern area of the Son Tra Peninsula were found to be damaged by plastic waste, fishing nets and fishing boat anchors.

Damaging human activities

“Ghost nets must be viewed as an environmental calamity that affects not only corals but also marine ecosystems. Every year, team members catch more than ten tons of nets," Le Chien, the Sasa team's founder, told FairPlanet about discarded fishing nets. 

After every storm season, ghost nets are cornered into the reefs. The constant oscillations of the water cause these nets to move thousands of times a day and scrape the coral's soft tissue, causing the damaged areas to die. Nets the perfect medium for algae to grow and compete for the habitat, and also block light sources, causing the coral to bleach, Le Chien explained. 

In addition, some fishermen even dive into the sea, pumping cyanide to catch fish while having no idea that the polyp shells of corals die when exposed to such chemicals.

Rising sea activities are another reason for the demise of corals, particularly in a tourist destination like Da Nang. Trash from popular snorkelling tours has been harmful to coral reefs. The waste becomes tangled with coral branches, creating a large dump floating at sea. Visitors often step foot on corals during the experience.

Researchers focus on the long-term process of monitoring. A greater understanding of the structure, functions, ecological processes and causes of coral reef degradation is deemed fundamental for boosting the effectiveness of coral reef management. In the meantime, some organisations seek to remove nets from feeds and perform other biological restoration methods.

The researchers also suggest that the active participation of local communities in coral reef monitoring is necessary and important in order to increase future coral reef research capacity and management in Vietnam.

Image by Harris Vo.