Seaweed threatens reefs

Kappaphycus alvarezii and Eucheuma denticulatum seaweeds had been introduced to commercial level in 20 countries around of the world, in effort to motivate poor communities located in coastal areas of the tropics to cultivate them and acquire an extra source of income; unhappily the general result was a failure. In the south of India, for example, the k. alvarezii invaded the Reserve of the Manmar Gulf, covering reefs and killing entire colonies.

These seaweed species are called “hard”, since marine animals do not consume them, and exclusively cultivated for carrageenan extraction, agglutinant used in innumerable nourishing products. Nowadays, they are produced about 120mil tons per year in Philippines and Indonesia, native countries of these species.

E. enticulatum

K. alvarezii

The introduction of those seaweeds in Hawaii was made 30 years ago by a professor of the Hawaii University, Max Doty, creator of culture techniques that had been exported worldwide. Today, the country suffers with the infestation of the two species, which spread into the coast with a growth of 7% a day, covering reefs, frightening fish and destroying the local fauna.

Dead reef

The uncontrolled growth of the seaweed is resulted of a badly planned and executed project, in witch cultural factors of the region and public and private initiative integration had not been taken in account. Without having whom to sell or receiving low values for the seaweed, the majority of producers abandoned its cultivars, which today grow freely becoming one of the biggest ecological concerns in Hawaii.

Reef destruction by seaweed growth

Fighting against the reef degradation, the University, State and the Nature Conservancy had invented the “Super Suckers”, vacuum cleaners attached to Catamarans that suck up to 1,3 tons of seaweed per day.

- “In the current situation we would need 10 years to clean this bay”, said Brian Hauk, governmental supervisor of invading aquatic species.

"Super Sucker" and diver removing seaweed

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