THE GREAT BARRIER REEF

The Great Barrier Reef is the largest living ecosystem in the world. It has been around for many millennia and is continually growing and changing. It is a network that spans across 2,600km and is made up of corals, seagrass, islands, and cays that is make up the Great Barrier Reef Marine Park.

It is said that the reef dates back as much as twenty million years ago, with an ever-changing landscape and coastline. It has moved and morphed over the years and was first encountered by humans 40,000 years ago when Aboriginal and Torres Strait Islander peoples settled in the area. The current reef is about 6,000 to 8,000 years old and was formed after the last ice age began to recede and water levels and temperatures rapidly changed.

THE FORMATION OF THE REEF

The Great Barrier Reef that we know today actually sits on what is the remains of the sediments of the Great Dividing Range, a huge mountain system. Corals began to form around the base of these mountains, which at the time were continental islands. Once sea levels began to rise, the growth of coral began to creep up the mountains, which were eventually completely submerged, leaving behind small islands, barrier reefs and atolls that we know and see today. The Whitsunday Islands, for example, are the remains of mountain tops that once towered over the region which is now surrounded by fringing reefs.

All reefs, including the Great Barrier Reef, begin to form with a single organism. A drifting coral polyp, expelled into the open sea by its parents, will come to rest on a stationary object, such as a rock or shell, where it will permanently attach itself to live its life. Here is where we see the humble beginnings of a reef.

After they settle, polyps will begin to secrete a calcium carbonate, which hardens to form the bony white structure, or skeleton, that forms the shape of the coral itself. The polyp lives on the outside of this bony structure, where more of the same species will join it, becoming one organism. The polyps develop a relationship with algae, which is its source of food and its colour, which gives the coral its look. The healthy coral will continue to grow at a rate of about 5mm - 20cm per year, depending on the species, and grow best in temperatures between 21C and 29C.

COMPETITION ON THE REEF

Other types of corals will settle in the same area, expanding and fighting for space and resources, until you eventually have a fully developed coral reef. Hard and soft corals are formed in similar ways and will eventually form on older, dead corals, always expanding and growing, changing the shape of the reef. Other marine plants and fish will begin to move into the same area, using the corals for food, protection or mating grounds, creating an ever-fluxing ecosystem. A coral reef can be likened to a towering forest that began from a single seedling - once just a small single plant, it can become a diverse and vast ecosystem.

The Great Barrier Reef is currently home to 1,500 species of fish, six species of sea turtles, 30 species of whales and dolphins and 411 species of hard coral. It is constantly changing before our eyes and is an ever-growing system. As visitors to the reef, it's important that you don't touch or interfere with corals and marine species on the reef, so they continue their natural life cycle and allow the reef to continue to be healthy and thriving.

What kind of things you can expect to see?

There are thousands of individual species that live in the Great Barrier Reef Marine Park. From birds to mammals, fish and corals, there is a huge variety of what can be found above and below the water. Below we have listed some exciting things you can expect to see when snorkelling in particular.

Coral

Coral can be grouped into several categories, depending on what type you are looking at. You can see staghorn, brain, plate, mushroom, slipper, micro-atoll and bommies when below the waterline and sometimes from above. Staghorn and plate corals are the most abundant types of coral you will encounter when snorkelling and are easily spotted, even by novice snorkellers. Staghorns are the branches of coral that often resemble a bundle of tree branches, while plate corals look like plates, often stacked together.

Molluscs

Molluscs include clams, mussels, slugs, snails and octopi. In the Marine Park and the Whitsundays, you may see some species from this group such as giant clams, which have colourful fleshy lips, cone shells, which are extremely deadly if handled or touched, and sea slugs, which look like colourful kaleidoscopes of colour in the form of a slug.

Echinoderms

Echinoderms include sea cucumbers and sea stars, among other animals. Sea cucumbers are easy to spot, as they are long and spherical, like that of a real cucumber. They are slow moving and dark brown or black, making them easy to spot. You can often see sea stars (often miscalled starfish) around the reef as well. They usually have 5 arms, but some may have more or less, depending on the kind of life they've had! Echinoderms can grow back missing parts if they have been damaged or have been been a tasty snack for other marine animals, sometimes resulting in an uneven appearance.

Fish

The most noticeable species on the reef are the fish, of course! There are thousands of species that live in the marine park, many of which you will see on any snorkelling trip! They come in an amazing range of sizes, colours and temperaments. Some will be happy to come to greet snorkellers and hang out close by, while others may dart away and seek shelter from their visitors! You will see big, small, fast, slow, colourful and bland! Each and every species is different and adapted to their reef in their own way which allows them to survive and live their best life. Ask your tour guide and they may even be able to help you find Nemo!

Sea turtles

Sea turtles are a favourite among many snorkellers on the reef. Six out of the seven species of sea turtles in the world live on the Great Barrier Reef. The most commonly spotted in the Whitsundays is the green sea turtle, which can often be found munching on coral. Older, more mature sea turtles are more often spotted from above the water in the seagrass beds when they surface for air. The younger turtles that are often spotted when snorkelling are content to mind their own business as you snorkel around them, but will swim away if you frighten or disturb them! The best way to enjoy their company is to maintain your distance, admire them from afar and never block their path to the surface. They breathe air just like people do and need to make their way up from time to time.

Mammals

You are less likely to see sea mammals than any other marine species when snorkelling. They are much fewer in number and often stay away from noise and boats. You may see whales or dugongs when you're above water, but less likely when you're snorkelling among the reefs.

SAILING THE WHITSUNDAY ISLANDS AND THE GREAT BARRIER REEF

The World Heritage-listed Great Barrier Reef is one of the seven natural wonders of the world and the largest living structure. It is visible from outer space and stretches over 2000 km in length along the Queensland coast in Australia.

The Whitsundays region is ideally located near the central section of the Great Barrier Reef and is the perfect base to explore this aquatic wonderland. The Great Barrier Reef protects the Whitsunday Coast and Islands from huge ocean swells providing the region with some of the safest and smoothest sailing and cruising waters in the world.

Remember - this is a reserve! enjoy your stay, but don't leave you

Destination Spotlight: The Great Barrier Reef