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BARNACLES & MANGROVES

The photo below shows the barnacles on the mangrove trunks in Cau Ngang district of Tra Vinh province, which MangLub VN would like to introduce in this writing.



Barnacles are crustacean sub – phylum instead of the molluscs, and one of the oldest animals in the world. The scientists discovered about 1,220 species of barnacles, and most of them are hermaphrodite. The ideal habitat is in the salinity areas. The barnacles are one of the threats to the ships, or other buildings along the seas. Why? The barnacles live on any hard objects like the carapaces of crabs, oysters, turtles or any surface that they find suitable like vessels.


So, how do they live on these objects? The barnacles secrete a fast curing cement that helps them glue on the surface. Once they can be glued to the surface, they will not leave forever. It is said that the ship speed reduces about 50% if the barnacles reside on the undersides. Thus, they cause the headaches to the fishermen for centuries.


The popular barnacles are rock barnacles, or acorn barnacles, and goose(neck) barnacles. Unlike rock barnacles, in Spain, Italia and in Quang Ninh, Hai Phong of Vietnam, goose barnacles are deliecous and expensive foods in classy restaurants. Barnacles are natural living matters, and can not be raised. Thus, goose barnacles are considered the rare and healthy seafood. In Spain, a kilogram of goose barnacles is about 200 EUR.



Now, let’s back to our mangrove trunk covered with the barnacles. Do you know what its name is? They are called Amphibalanus Improvisus, with a diameter of about 10 mm. It is now recognized as a widely distributed species in tropical waterways, especially at the estuaries from brackish water to salinity water, causing lots of harms to the mangrove trees, and also increasing the mangrove mortality.


  • The barnacles reside on the trunks, the leaves, the roots, impeding the gas exchange and photosynthesis. Especially for the Rhizophora Apiculata trees, the roots can not grow if the barnacles density is high.


  • The barnacle’s weight usually exceeds the the weight of the mangrove trees, causing that newly planted mangrove trees can not tolerate, and finally collapse.



As mentioned above, once the barnacles stick to the surfaces, with its special glue, they can live on the surface forever. The fishermen have to burn them after returing from the sea. And it’s unable to remove them from the mangrove trunks by knives. This way will affect the underlying tissues of the trees. Thus, for vast areas of mangrove, the barnacles is considered as one of the most serious causes to the mangrove mortality.

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