The Majestic Turtles of the Great Barrier Reef

Beauty that condemns.

The Hawksbill Sea Turtle is regarded as the most beautiful turtle in the ocean, intricate patterns and colourful shells have caught the attention of illegal animal traders. The highly sought after “tortoise shell” is used to make jewellery and trinkets and has caused the species to be hunted near extinction. They can also be identified by their serrated and overlapping shells that define the rim of the shell. Named after their pointed beak, this unique design helps them dig out sea sponges between the coral. Unlike other sea turtles, sea sponges are their main food source. Its because of this diet preference that the hawksbill can be mostly found in shallow waters, close to coral reefs and rocky areas. Their beaks are perfect for squeezing in between small crevices and digging out food. 

The Great Barrier Reef here in Australia provides these hawksbill turtles with the perfect feeding ground, and that’s why Queensland is home to some of the largest nesting grounds of these turtles. 

Wanna catch some rays?

It’s a known fact that turtles are ocean wanders, however this group of females have their annual holiday destination all figured out. There are 10- 25 hawksbill females that return to the sandy beaches of Hawaii every year, not just laying eggs like other turtles, but to bask in the glorious sunshine. These particular females spend the day resting on the shore before returning to the ocean at night. Sounds like a holiday to me! 

Wild Facts

The Hawksbill turtle population has declined by over 80%, commercial fishing and marine plastic would have a large part to with this, but mainly because of the “tortoise shell” black market. These turtles are never hunted for meat because their diet is primarily sea sponges which causes their flesh to be toxic for human consumption. 

Size: 60 -90 cm

Weight: 45 – 68kgs

Lifespan: 60 years 

Location: India and Indo-Pacific Ocean

The Flatback Sea Turtles

The odd one out. 

If you lined up all the sea turtles that visit Australian waters, they would all look different, but one major similarity would be they all have a rounded shell. The flatback turtles therefore can be easily identified as they are the only species that don’t. Because of this their shells are not as strong and easily crack under pressure so they rarely go deeper than 60 metres. 

What is the flatback turtles favourite country?
Australia! In fact these sea turtles love this country so much that this is the only place they will breed and nest their eggs. In comparison to other species, the flatback only lay around 50 eggs per nest, that’s half the amount of other turtles. They also don’t migrate to other countries, but rather stay in the shallower waters to feed. The flatback turtle eggs will begin hatching in December and continue until March. 

Tasty, said the crocodile.

As these turtles favour the warm waters of Australia, it means their main predators are saltwater crocodiles. However their population faces other threats such as direct hunting for meats and eggs, nesting beaches are disrupted for coastal development, and pollution. 

Wild Facts.

The gender of turtles is determined by the temperature of the sand in which the eggs have been laid. If the sand is below 29 degrees the turtles will be males and if the temperature is above 29 degrees the turtles will be female. 

Size: 75-95 cms 

Weight: 70-90 kgs

Location: Australia, Papua New Guinea 

Lifespan: 100 years 

• Straya Mate.The most common turtle to be found here in Queensland is the Green Sea Turtle. Female green turtles will return home to the place they themselves were born, the majority being from The Caribbean and Australia. The Great Barrier Reef has some of the highest number of nesting green turtles to be found in the world. Giving us greater chances of seeing these beautiful animals out in the wild. Green Machine – “only vegetables for me please” – said the green turtle. The Green Sea turtle is a strict vegetarian, eating only seagrass and algae. It’s because of this the green turtle has earned its name, not because of its green shell or green skin, but because of its green coloured fat. This turtle will start its life in the open ocean, feeding on various different foods such as jellyfish, however as it matures to around 5 years of age, the green turtles will seek new feeding grounds closer to shore. They will travel vast distances across the open ocean to find luscious green fields of seagrass and continue the rest of their lives as herbivores.Just like trimming the grass at home, turtles feeding on seagrass helps keep the seabed healthy and productive. What’s more, as the turtle digests the grass the nutrients are passed back into the seagrass ecosystem to nourish other small sea creatures and fish. Wild Facts. 

  How many countries have you visited? The green sea turtle can be found in over 140 countries around the world. 

  Only 1 out of 1,000 will make it to adulthood. Although female turtles will lay hundreds of eggs, very few survive. Depending on the species of turtle it can take up to 20 years for a turtle to be fully grown and during that time each turtle faces threats from other predators, human hunting and marine plastic. 

  Lifespan: 100+ years 

  Weight: 136 to 159 kg

  Size: 91 to 122 cm

  Location: Subtropics of the Atlantic, Pacific, and Indian Oceans, and in the Mediterranean Sea.
  Figure 1 Indicative migration path of Great Barrier Reef green turtles

  

   

  Figure 2: Great Barrier Reef green turtle nesting sites

   

  Green turtle facts

  • Breeding season – Late October to February
  • Years between breeding – Two to eight years
  • Ages when female first breeds – 45 years
  • Age when move into feeding area – Four to seven years (30 – 40cm carapace length)
  • Nesting female length – 107cm (range from 91 – 124cm)
  • Nesting female weight – 130kgs (range from 98 – 184kg)
  • Clutch size (number of eggs) – 115 eggs (range from 62 – 153 eggs)
  • Hatchlings emerge – December to May
  • Hatchling success – 84 per cent
  • Hatchling size – 4.97cm (range 4.02 – 5.19cm)
  • Hatchling weight – (24.83g from 19.8 – 28.4g)
  • Predators of hatchlings – Crabs, herons, dingoes and fish such as trevally and sharks