The crown-of-thorns starfish (Acanthaster planci), known as the "coral killer," has been rampantly invading coral reef areas worldwide in recent years. To curb the spread of crown-of-thorns starfish in the Dongsha atoll, the Marine National Park Headquarters of the Ministry of the Interior National Park Service (hereinafter referred to as " Marine National Park Headquarters ") has been conducting continuous underwater monitoring. Based on the monitoring results, from June 6 to June 12 of this year (2024), a crown-of-thorns starfish removal operation was carried out in the Dongsha atoll. After a week of effort, approximately 1,840 crown-of-thorns starfish were removed, temporarily alleviating the coral ecological crisis in the Dongsha atoll waters.
Crown-of-thorns starfish found damaging coral on the southwestern side of Dongsha Atoll's outer reef.
The Marine National Park Headquarters has established about 20 fixed monitoring stations in the waters of Dongsha Atoll National Park, conducting underwater surveys annually to monitor the health of the coral reef ecosystem. This year, in the northern, eastern, and southern waters of Dongsha atoll, no crown-of-thorns starfish were found, as in previous years. However, in the southwestern area of the reef platform, an abnormal increase in the number of crown-of-thorns starfish was discovered, with densities of 20 to 30 per 100 square meters in some areas. The coral in this region is often heavily grazed by the crown-of-thorns starfish, causing significant ecological damage.
The Marine National Park Headquarters, drawing from its experience in the South Penghu Marine National Park in 2012-2013, when an abnormal increase of crown-of-thorns starfish was found in the Xiji waters, immediately collaborated with the Biodiversity Research Center of the Academia Sinica to gather divers for a removal operation. After two years of continuous removal, the situation was effectively controlled. This year’s operation in Dongsha combined the expertise, personnel, and methods of the Biodiversity Research Center of the Academia Sinica researcher Ming-Xiu Zheng, who had previously worked on crown-of-thorns starfish removal at Taiping Island, as well as professionals from the Dongsha International Ocean Research Station of National Sun Yat-sen University and the Kenting National Park Headquarters. In the southwestern coral reef area of the outer Dongsha atoll, at a depth of about 10-15 meters, the crown-of-thorns starfish were removed using vinegar injection and manual clipping techniques. Despite having only seven divers, a total of nearly 1,840 crown-of-thorns starfish were removed in just six days, demonstrating significant success in alleviating the damage to the coral of Dongsha atoll.
Coral reefs worldwide face threats; monitoring and removal efforts are urgently needed.
In recent years, coral reef ecosystems in various regions, including the Great Barrier Reef in Australia, Okinawa in Japan, the Xisha Islands in China, and surrounding countries in the South China Sea, have all been threatened and damaged by the crown-of-thorns starfish. Similarly, the waters around Taiwan are also severely impacted by this issue. The exact cause of the crown-of-thorns starfish population explosion remains undetermined, and further research by the academic community is needed to establish an early warning system. The Marine National Park Headquarters continues to employ the simplest, most direct, yet clear and effective methods to conduct regular coral reef monitoring. Once an abnormal crown-of-thorns starfish population is detected, immediate removal actions are taken to prevent further damage and expansion. The Marine National Park Headquarters oversees the Dongsha Atoll and South Penghu, two marine national parks that harbor Taiwan's most critical coral reef habitats. In the future, the Marine National Park Headquarters will continue to closely monitoring the coral reef ecosystems in the waters in the, track the distribution and population of crown-of-thorns starfish, and expand removal operations when necessary, aiming to effectively control the crown-of-thorns starfish population, reduce the damage to coral reefs, and maintain a rich and healthy coral reef ecosystem in the national park waters.
