Our correspondent Chris takes a dive trip out on Australia’s Great Barrier Reef, exploring the fragile ecological environment which is a diver’s paradise of crystal clear blue water and abundant fish life.

The Great Barrier Reef — as potent a symbol of Australia as Sydney Opera House and Kangaroos. At 2500 km long, it is the only living organism which can be seen from space with the naked eye. It’s famous because its big. The problem for the visitor is how to experience that vastness when at best you can only take a peek at one small section.

As a diver the choice was clear — break the bank and take a live-aboard chartered dive boat to the outer reef in the far north, where the day boats rarely clatter the waters and the reef is still preserved in all its glory. I booked with Taka dives for a four-day excursion out of Cairns to swim with sharks, feed giant cod and gorge myself on the most pristine coral reefs the planet can offer. My vessel was Taka 11, a former shrimp trawler rebuilt as a custom dive ship.

That evening I watched the sun set over Cairns, the diving capital of North Queensland, as we set out for the Ribbon Reefs. The long chain of fringe reefs mark the border between the Barrier reef and the Pacific. By the next morning I was awake and part of the busy pre-dive activity on deck. The reef stretched from one corner of the horizon to the other — a tranquil turquoise in the expanse of azure blue sea. I was about to dive the world famous “Cod Hole”.

Now Potato Cod may sound like some kind of frozen, pre packaged version of fish and chips, but this is one of the premier dives on the Barrier Reef. Here you swim with fish the size of dumper trucks. Stroke them, feed them, tickle them, even kiss them if you’re so inclined. These cod are in fact giant groupers misnamed like so many species in Australia because somebody thought their Dalmatian spots resembled children’s potato prints.

With their thick Mick Jagger lips and large dapple grey bodies, these guys have the ferocious look of an aquatic bulldog, but are as gentle as a lap cat.

We did two dives here slowly descending amongst the gentle giants. The underwater world was buzzing as we mixed with huge green Maori wrasse, red bass and schools of smaller fish. We see a giant moray with a small fish taking its life in its hands as it swims in and out of the opening mouth of the eel. These small cleaning fish play the role of reef dentist, keeping everyones teeth clean while feeding from the very jaws of its big brothers.

That night we set sail for Osprey Reef, 161km off shore, beyond the Ribbon Reefs in the open ocean. I foolishly disregarded the advice to take a sea sickness tablet and spend the night feeling like I’m sleeping on a roller coaster. I sit through the following mornings dive briefing turning ever paler shades of green before dispatching breakfast over the port side. This was the shark dive and while a large portion of me would rather have crawled back to my bunk and died, I had the calming thought that below the waves was the one place not rolling all over the shop.

It’s strange how you can start out diving worrying there’s nasty things like sharks down there and then gradually start feeling cheated when you don’t come across the beasts. At Osprey there’s tons of them — white tips, black tips, grey whalers all milling around and looking suitably menacing. The majority are far too small to even contemplate braking their jaw by taking a chunk out of you. Hammerheads could if they tried it, but hopefully they don’t know it. We watch in awe as two hammerheads glide past silhouetted against the blue. We hang motionless at 20m as these great predators of the sea watch us from their twilight world beyond the safety of the reef. Like some strange aliens from the X Files, two, three metre sharks with something like a skate board for a head.

Sci-Fi writer Arthur C Clarke said he took up Scuba because it was the nearest he could get to the weightlessness of space. He might also have thought the coral world of the reef was the nearest any of us would get to feeling like we’d landed on another staggeringly beautiful and yet bizarre landscape formed by millions of tiny polyps.

Yet tragically, in this the international year of the ocean, these precious habitations are being destroyed faster than the rain forests. Around the globe, climate change, dynamite fishing and cyanide fishing are taking their toll. For the Great Barrier Reef, the problem is sugar. The thousands of kilometres of sugar cane fields which created a monotonous panorama the length of Queensland are washing their alluvial waste in the direction of the reef It remains to be seen then, what arrangement two of Queensland’s largest industries, sugar and dive tourism, can broker in order to save this world heritage site.

“Third day is the best diving of the lot” announced dive leader Brad. “What — after swimming with sharks and feeding giant cod? Surely not?” He was right of course, the last day’s diving topped the lot. Spiralling up the underwater pinnacle of “Steve’s Bommie,” we were constantly enveloped in schools of hundreds of blazing yellow goat fish and silver blue trevally. The closer to the sunlight, the more dazzling the confusion of colour. At the top of the Bommie it was a clown fish party. Hundreds of the little scarlet fish were darting in and out of their anemone homes.

A more angelic “Temple of Doom” would be hard to find. The afternoon’s dive site was an A to Z of coral. Huge sea fans, gorgonian corals, table corals, horny corals. They looked like the trees and hedgerows of the reef but they were all animals. They built their stony skeletons in the most remarkable plethora of sham and covered them in beautifully saturated purples, yellows, oranges pinks and blues. For me it was just the sense of being there, hanging in space amongst the tiny electric blue and green fusiliers above their Home the reef.

We were certainly spoilt on this trip and one last treat was the site of a minke whale. Her blank fin and back arched up out of the water, keeping us company on the trip home. A fitting finale to a wonderful trip.

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