Reef walk

As the tide goes out there are all sorts of creatures that can be viewed on the reef. It was a perfect Whitsunday winter's day - blue sky and no wind - for exploring the reef from Hydeaway Bay, Cape Gloucester, top of the Queensland Whitsunday islands.

Falling tide at Hydeaway Bay

On this day in July, the water was crystal clear - no rivers flow into this bay - so we could see plenty of marine animals and plants. There is a healthy population of sea cucumbers, filtering organisms from the sandy bottom.

Various green sea grasses swayed in the water amongst sea squirts, whelks and hermit crabs.

We were lucky to stop a Mantis Shrimp in its tracks with a reef bootie as it darted around. Look closely!

Sand dollars, which are flat burrowing sea urchins, are a common sight.

So too are microatolls. This is where corals growing on the reef flat encounter a barrier - the water surface at mid-tide level - above which coral tissue simply cannot survive. The presence of this barrier forms fascinating coral growth in which the colony continues to expand around its radius, but is dead on top. As the colony gets older, the dead patch may become hollowed out, and other corals may settle in the shallow lagoon so formed. These formations resemble miniature coral atolls and so are referred to as 'microatolls'.

If you are interested in an interpretative reef walk, Whitsunday Training has a permit from the Great Barrier Reef Marine Park Authority to conduct educational programs for schools and other study groups.