Can algae-eating fish save our coral reefs?

Coral reefs cover an area of less than a quarter of one percent of all the earth’s marine environment, yet they are one of the world’s most diverse habitats, supporting one third of all fish species, and have been growing in the world’s oceans for 450 million years.

Corals are colonies of tiny individual animals, known as polyps. Formation begins when free-swimming larvae attach to new land created by volcanic activity. The larvae then grow into polyps, and lay down calcium carbonate (chalk) cups that form the reef. Coral grows only on the very thin top layer and, over time, end up sitting on top of hundreds of metres of chalk, constantly growing upwards.

A young Charles Darwin became enthralled by coral reefs on his epic Beagle voyage, and made their formation the subject of his first scientific publication. On seeing them in the Indian Ocean in 1836, he wrote in his journal, 'we feel surprise when travellers tell us of the vast dimensions of the Pyramids and other great ruins, but how utterly insignificant are the greatest of these, when compared to these mountains of stone accumulated by the agency of various minute and tender animals!'

Yet these mountains cannot grow...

To view the rest of this article - you must be a paying subscriber and Login