Great Barrier Reef - Lizard Island

Remember at the beginning of my story when Captain James Cook ran his ship aground on what he thought was rock but was, in fact, the Barrier Reef? After weeks of repairing his ship, Cook searched for safe passage north. He sailed to Lizard Island, anchored off in one of the bays, and hiked up to the highest point, now called Cook's Look, on the northeast of the island to find a way out of the reefs.

Cook was responsible for naming Lizard Island. As you may have guessed, the only land animals he saw were lizards. There are 11 species of reptiles on the island. The most common one is the yellow-spotted monitor, seen wandering around the resort area but found all over.

Lizard Island is the northernmost and last resort island in the Barrier Reef. It is wonderfully pristine with crystal clear waters and an impressive 24 white beaches to frolic on. At the southern end is the deep Blue Lagoon encircled by fringing reefs and three smaller islands.

While Lizard Island is a fantastic haven to escape, it also holds some sad environmental events. Over the last six years, the island has been impacted by coral bleaching four times. Coral bleaching is a result of zooxanthellae being turfed out by polyps when they are under stress. When water temperatures rise, the zooxanthellae produce too much oxygen which the polyps cannot handle. When the zooxanthellae have left, taking the colour pigment with them, the polyps turn white, hence the term bleaching. Polyps can live without zooxanthellae for a short time, but without their food source, they eventually starve and die.

Halfway between Seabird Islet and South Island is a spot illustrating the effects of coral bleaching. Mounds of staghorn coral are devoid of colour, unlike the giant clam right next to it. Some of the Acropora gemmifera, a type of stony coral near the clam, are almost fluorescent purple. It looks stunning and is easily considered healthy, but the colour is a protein released by the coral acting like sunscreen against rising water temperatures. It’s like its final stand.

Some of the coral at Lizard Island have an opportunity to recover and repopulate, provided the weather conditions remain within a reasonable range. Only time will tell.



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Great Barrier Reef - Norman Reef

I'm zigzagging across the Great Barrier Reef, first out on the shelf at Myrmidon, then back in the inner reef at Fraser Island, and now back on the shelf at Norman Reef. It is a small reef, but it is well-known as one of the best diving sites in the region.

Not wasting any time, I got in the water and started exploring. The visibility was excellent, letting in plenty of light on the corals. Large spreads of green lettuce coral were next to the fast-growing staghorn coral. There were helmet-shaped porites and plate corals that looked like dinner plates. Have you ever seen brain coral? They look just like brains! Many varieties are present, making identification a challenge.

Well, no matter because the green sea turtle gliding above the colourful coral garden was a fabulous distraction. It is one of seven species found on earth, of which six live within the Great Barrier Reef. The green turtle is a solitary creature, except for mating season, and is the most common turtle species seen on the Barrier Reef. While most turtles are omnivorous, green turtles are herbivorous as adults, eating algae and seagrass. Females may travel thousands of miles between feeding and hatching grounds. They often return to the beach where they were hatched to lay their own eggs, anywhere between 100-200 per hatch. The gender of the hatchlings is dependent on the temperature of the eggs. Those buried in deeper sand where it's cooler will hatch boys, whereas eggs laid in warmer or shallower sand will hatch girls.

Green sea turtles grow to about 5ft (1.5m) long, and their carapace turns completely brown at maturity with various patterns. Naming them "green" is not about their colour; it refers to the green fat that lies beneath their shell, resulting from their vegetarian diet.

Turtles are ancient creatures who lived with dinosaurs. The closest ancestor to modern sea turtles is Desmatochelys padillai. They lived during the Cretaceous period, around 120 million years ago, when reptiles ruled the ocean and were at the top of the food chain. It is hard to imagine sea turtles as apex predators, given that they are on the endangered species list these days. But there they were, hunting in the wild oceans alongside plesiosaurs and ichthyosaurs.

I am glad today's sea turtles are docile reptiles. It allows me to observe them without worrying about being the next meal.



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