David Harasti is the Research Scientist with the Port Stephens-Great Lakes Marine Park

The Port Stephens-Great Lakes Marine Park is well known for its huge variety of marine life. Marine animals such as whales, seals, dolphins, turtles and many types of fish call the marine park home. It’s this marine life that makes the area a very popular destination for tourists to visit and enjoy and the protection provided by the marine park is to the benefit of these species.

Not many people are aware of the fact that Port Stephens has a large population of resident marine turtles, with three species of turtles occurring. The most common species are the Green turtle and the Loggerhead turtle and occasionally the Hawksbill turtle can be seen. Two other turtles have been recorded in the offshore waters of the marine park; Flatback and Leatherback turtles however their occurrence is rare. Turtles are better known from the warm tropical waters of the Great Barrier Reef, however in a scene straight out ‘Finding Nemo’ they have travelled down on the East Australian Current and taken up residence in Port Stephens where they appear to live for long periods.

Green Turtle:

The Green Turtle can be found feeding on seagrasses throughout the Port; snorkelling and diving around Fly Point inNelsonBayprovides a good chance of encountering one. The Green Turtle is the most typical sea turtle, possessing a teardrop-shaped carapace and a pair of large, paddle-like flippers. Despite the turtle’s common name, it is lightly-coloured all around while its carapace’s hues range from olive-brown to black. The turtle is actually named for the greenish coloration of its fat and flesh.

Loggerhead Turtle:

The Loggerhead is a large turtle which a much bigger head and is so called because of its large head and thick muscular jaws, which it uses to crush food such as crustaceans, molluscs and jellyfish. Unfortunately plastic bags look like jellyfish and loggerheads often die from ingesting plastic bags washed into our waterways so it’s important that any plastic bags are disposed of correctly. Most loggerheads grow to about 1 m long and can weigh up to 150 kg.

Hawksbill Turtle:

The Green and Hawksbill turtles look very similar to each other however they have some differences in appearance. The Hawksbill can be distinguished from the Green turtle by its sharp, curving beak with prominent cutting edge, and the saw-like appearance of its shell margins. Sponges are the principal diet of hawksbills once they enter shallow coastal waters and begin feeding on the bottom. Hawksbills are also known to feed on other invertebrates, such as comb jellies and jellyfish.

Satellite Tracking:

The Marine Parks Authority has released a total of five marine turtles with satellite tags since the tracking project began 12 months ago. The famous five include three Green turtles, a female Loggerhead turtle and the latest addition of a female Hawksbill turtle released last month. The two female green sea turtles where released in May and August last year, aged around 15-20 years that were nicknamed Tracey and Crabby (nick named after been found tangled in a crab trap). Four of the five turtles have been found to reside in the waters of Port Stephens. Tracey has been found to call the waters of Fly Point her home, as she hasn’t ventured more than 2km from the site in the past 12 months. She has become a bit of a local celebrity, with scuba divers seeing her on a daily basis either sleeping in her small cave or feeding amongst the seagrass or just happily swimming past.

Max a mature male Green turtle weighting over 100 kg and well over 1 meter in length was released in December last year after spending several weeks at the Taronga Wildlife Hospital. Max has now returned to Port Stephens after a 1200 km sea odyssey which lasted 3 months and took him as far south as Batemans Bay and included a lucky escape from a shark net south of Sydney.

Each turtle was fitted with a small satellite tag on the back of its shell, about the size of a mobile phone, which sends a signal to overhead satellites whenever the turtle surfaces. The tags are expected to send a signal for 6-12 months depending on battery life.

Stripey (pictured above) is the latest turtle to assist research Marine Parks research. However instead of being fitted with a satellite she has a white stripe on her shell. This will enable local divers to sight and report her whereabouts to Marine Parks via spotting registers in store at Lets Go Adventures.

Conservation:

All marine turtles are protected inAustralia. The main threats are marine debris, pollution and changes to important turtle habitats, such as coral reefs, seagrass beds, mangrove forests and nesting beaches. The major threats to turtles in Port Stephens are accidental entanglement and drowning in fishing gear, especially crab traps, and injury caused by boat strike. Care needs to be taken when driving boats around the Port to watch out for the turtles as a boat strike can cause serious injury to a turtle and may result in death.

Last Modified: Friday, June 29th, 2012 @ 05:47

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