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Marine Turtles

Marine Turtles

The inshore coastal areas of the Fitzroy Region provide important habitat for green, loggerhead, hawksbill and flatback turtles. Olive ridley and leatherback turtles have also been recorded in the area. All species of marine turtles are listed as vulnerable or endangered under both State and Federal legislation. Marine turtles are at risk from boat traffic where a boat strike usually causes trauma from propeller damage to the carapace (their shell). Scarcity of seagrass as a food source causes stress to turtles, especially to green turtles, whereas other species such as Loggerheads, which have a more diverse diet, can be more resilient. During the 2010–11 floods, stranding records for turtles along the coastal catchments increased considerably, an indication that food sources were affected and resulted in many turtles starving.

Click on the thumbnails below for a larger image

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Loggerhead

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Hatchlings

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Olive Ridley

 

 

 

 

 

 

Conservation status of marine turtles found in the Fitzroy Basin marine region (Source: EPBC website, NCA website).

Common name Conservation status under Federal and State legislation
EPBC NCA
 
Flatback turtle Vulnerable; migratory Vulnerable
Green turtle Vulnerable; migratory Vulnerable
Hawksbill turtle Vulnerable; migratory Vulnerable
Leatherback turtle Vulnerable; migratory Endangered
Loggerhead turtle Endangered; migratory Endangered
Olive ridley turtle Endangered; migratory Endangered

Flatback turtles

Marine turtle

Flatback turtles are found only in the tropical waters of Australia, New Guinea and Indonesia and nesting only occurs in Australia. The Australian populations of flatback turtles in Australia are generally thought to be stable. The eastern Queensland population (one of Australia’s four recognised genetic groups) occurs between Bundaberg and Torres Strait.

Major nesting sites (rookeries) are found at Peak Island and Wild Duck Island, and a smaller rookery on Curtis Island. It is estimated that about 10% of the global population of Flatback turtles nest at these two rookeries.

Unlike other turtles that have oceanic phases to their life cycles, flatback turtles remain within the waters of the continental shelf. Flatback turtles spend most of their time in sub-tidal soft bottom areas of the Reef, coming ashore to nest on sandy beaches. They mostly eat squid, soft corals and jellyfish.

Green turtles

gbrmpa1295588Green turtles are found in tropical and subtropical waters throughout the world. Internationally the population is estimated to be large (about 2.2 million) although there have been severe declines in some countries, such as Indonesia. The total Australian population is estimated to be more than 70,000 individuals, with the southern Reef population increasing.

Key nesting sites in the southern Reef are found in the Capricorn and Bunker Island Group (e.g. Heron Island, Lady Musgrave Island) with other nesting sites at Curtis Island, Facing Island and Mon Repos.

Green turtles spend their first five to 10 years drifting on ocean currents. Once they reach 30–40 cm shell length they settle in foraging habitats such as coral and rocky reefs and inshore seagrass beds. Green turtles mainly feed on seagrass and algae. They migrate from foraging to nesting grounds (on average 400 km), usually returning to the same island beach to nest, between October and March.

Hawksbill turtles

gbrmpa1239278Hawksbill turtles are found in tropical, subtropical and temperate waters around the world, but globally their numbers have been decimated by hunting for tortoiseshell. Australia has the largest breeding population of hawksbill turtles in the world, with two distinct populations in Western Australia and the Great Barrier Reef. Hawksbill turtles can be found throughout the Great Barrier Reef but primarily nest on islands in the northern areas and Torres Strait. There is some evidence that the Great Barrier Reef population is in decline.

Hawksbill turtles spend their first five to 10 years drifting on ocean currents. Once they reach 30–40 cm shell length they settle in foraging habitats such as coral and rocky reefs and inshore seagrass beds. Hawksbill turtles feed almost exclusively on sponges. Like green turtles, they migrate long distances from foraging to nesting grounds.

Loggerhead turtles

gbrmpa1130362Loggerhead turtles are found in tropical, subtropical and temperate waters around the globe. In Australia, loggerhead turtles are found in Western Australia and the southern Great Barrier Reef, where major nesting areas are concentrated in coastal areas around Mon Repos, the Capricorn-Bunker Group of islands and the Swains Reefs. The Australian population is estimated to be 2–4% of the global population.

Like many other turtles, juvenile loggerheads drift in ocean currents for about 15 years before returning to foraging sites. Loggerheads use a wide variety of habitats, feeding on bottom dwelling invertebrates such as molluscs. They nest on sandy beaches from November to March.