The Nha Trang Institute of Oceanography has recently discovered the species of single-leaf seagrass (Halophila decipiens) at depths exceeding 6 meters in the waters surrounding the Hai Tac Archipelago, located in Kien Luong District, Kien Giang Province.
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Single-leaf Seagrass (Halophila decipiens) |
Although the distribution area of this seagrass is not large, it contributes to demonstrating the richness of seagrass species in Vietnam. This also provides a basis for explaining why the dugong (Dugong dugon) often appears in these waters.
According to scientists, there are up to 10 species of seagrass in the waters of Kien Giang, attracting many rare and precious marine animals. Local residents have reported that for the past three years, a herd of about 10 dugongs has been spotted in the waters of the Hai Tac Archipelago.
Previously, a study by Associate Professor Dr. Nguyen Van Tien from the Marine Institute in Hai Phong indicated that the overall area of seagrass beds in Vietnam has decreased by 40-60% nationwide.
Currently, according to incomplete statistics, the area of seagrass distribution in Vietnam is estimated to be over 10,000 hectares.
In our country, seagrass often develops in coastal intertidal zones, around islands, river estuaries, mangrove forests, lagoons, and bays.
Seagrass species grow year-round but thrive best in spring and early summer, while their growth diminishes during the rainy season and storms.
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A single-leaf seagrass bed |
They can be found from the intertidal zone to depths of 3 – 15 meters, and even up to 28 meters (at Bach Long Vi Island). They adapt well to salinity levels of 0.5-3.4%, with substrates consisting of fine mud, sandy mud, coral sand, coarse sand, or gravel.
Seagrass beds play a crucial role in stabilizing and protecting the seabed through their root systems, sprawling stems, and fallen leaves. They help prevent or reduce coastal erosion and damage.
The role of seagrass in participating in the nutrient cycles of the seas and oceans worldwide is estimated at 3.8 trillion USD, with the economic value of 1 hectare of seagrass reaching up to 212,000 USD per year.
In Vietnam, preliminary research results indicate that the economic value, including both extractive (seagrass and accompanying species) and non-extractive (environmental ecology) aspects of seagrass, is relatively high (Cam Ranh Bay: 7,920,000 USD; Tam Giang-Cau Hai Lagoon: 1,628,000 USD; Bai Bon on Phu Quoc Island: 481,202 USD).
