THE CORALS OF MAGNETIC ISLAND
Magnetic Island is classified as an Inshore Fringing Reef. These reef types are dominated by corals which are adapted to the turbid water conditions found close to the coast, and most of these reefs also have a substantial cover of the brown seaweed Sargassum. Best areas of coral growth are found on the reef slopes in water 2-5m deep, where we find diverse communities with many different species. Here are some examples of the corals we see regularly on our Reef Eco-Tours.
A typical Island coral community with mixed Acropora and Montipora corals at Arthur Bay.
Staghorn Coral (Acropora spp.)
A large stand of staghorn Acropora with cardinalfishes, at Whitfield cove.
Vase Coral (Montipora spp.)
Vase corals are common around the Island, and when the colonies reach a large size, they grow into intricate whorled patterns and multi-layered terraces.
Boulder Coral (Porites spp.)
Porites are the biggest and most important corals at Magnetic Island and the whole GBR, as their skeletons build the framework of the reef. Porites may live more than 800 years and reach massive sizes, more than 20m in diameter. We regularly see Porites on the reef ecotours that are more than 200 years old.
Orange Bushy Coral (Acropora millipora)
Staghorn corals from the widespread genus Acropora, are fast growing but fairly delicate corals. They can grow up to 25cm per year, but are easily damaged by storms or careless snorkellers. Staghorns come in a range of colours including some spectacular orange, purple, and electric blue colonies found in Arthur Bay. They form an important shelter habitat for many plankton-feeding fishes.
Brain Coral (Platygyra spp.)
The coral Family Favidae includes species with a "massive" morphology, which means they grow like a large boulder in shape. Favids have large polyps, and in some species such as this Platygyra, the polyp walls are extremely contorted, giving the brain-like appearance of these colonies. The reefs around the island have a particularly diverse assemblage of Favid corals.