In the bright shallows of the Lord Howe Island lagoon, sub-adult green turtles thrive on a diet consisting mostly of seaweed, seagrass and invertebrates. Although this species is found throughout northern Australia, young turtles are known to drift on ocean currents down the east coast as far south as Batemans Bay.

Australia is home to six species of marine turtle: green (pictured), hawksbill, loggerhead, leatherback, flatback, and olive ridley – the first three also regularly travel south into the cooler waters of New South Wales.

A sub-adult green turtle takes a breath in the Lord Howe Island lagoon. When active, green turtles swim to the surface every few minutes to breath, but at other times, they can remain underwater for more than two hours on a single breath.

Exhausted from an evening spent nesting on remote sand cay on the northern Great Barrier Reef, a female green turtle returns to the sea. The northern Great Barrier Reef is home to five major green rookeries, while there are a further 13 in the southern section of the reef.

The risks of nesting are illustrated by this dead turtle found on a remote sand cay in the northern Great Barrier Reef. Female green turtles lay around five clutches of 115 eggs each at night. The turtles must then time their departure from the beach, to avoid the desiccating heat of the tropical sun, which can prove fatal.

A female green turtle rests in shallow water under the subtle colour palette of sunrise on a remote sand cay on the northern Great Barrier Reef. In 64 days time around 88% of the eggs she has just laid in a nest on a nearby beach will hatch successfully.

Dave Harasti (right) a scientist with the Port Stephens-Great Lakes Marine Parks Authority and ranger Christopher Gallen prepare to release tagged turtle Tracey at Fly Point, part of the marine park.

Tracey takes refuge in the sheltered waters of a sanctuary zone that encompasses Fly Point within Port Stephens. Tracey will be tracked for the next six months, after which time the tag is expected to shed with shell growth. More turtle tracking within Port Stephens is planned for 2012.

Tracey was the first marine turtle ever fitted with a satellite tracking device in New South Wales. For the past few months, Tracey has not ventured beyond 1km of her release location at Fly Point within Port Stephens harbour.

Christopher Gallen a ranger with the Port Stephens-Great Lakes Marine Parks Authority carries a turtle called ‘Crabby’ down to the shallows for her release after a tag is attached in Port Stephens.

One of two turtles tagged for a project off NSW, ‘Crabby’ was named after being rescued from a crab trap in Port Stephens. Encounters with marine debris such as fishing gear, and plastics often prove fatal for turtles.

A sub-adult green turtle (Chelonia mydas) tangled in a crab trap pays testament to the six or so marine turtles killed each year within Port Stephens alone. Green turtle populations are under threat globally from fishing nets, boat strikes, coastal development, pollution, marine debris, and loss of habitat.