Taronga Zoo tracks endangered sea turtles after they ingest plastic
X-Ray of a Green turtle that swallowed a fishing hook. Photo: Madeleine Smitham
Libby Hall never buys balloons. She also avoids groceries that are smothered in plastic wrap.
As the manager of Taronga Zoo’s Wildlife Hospital, she has seen the devastating impact plastic has on marine animals, especially the nearly dead sea turtles people bring to the hospital.
« They’re usually totally debilitated when they arrive. They’ve washed up on the beach or are found floating in the water, » said Ms Hall.
A young Green turtle that was nursed back to health by Taronga Zoo after ingesting plastic. Photo: Madeleine Smitham
« We had a turtle come in recently that had four different colours of balloons in its stomach. It had a whole party going on in there, » she said.
Every variety of sea turtle is is now classified as endangered, and yet scientists have much to learn about these global travellers.
For the past 18 months, Ms Hall and the zoo’s vet, Kimberly Vinette Herrin, have used satellite trackers to follow the movements of teenage sea turtles, following their ocean jaunts during a part of their life cycle that remains a mystery. So far they’ve released six turtles.
Taronga Zoo Wildlife Hospital manager Libby Hall releases a Green turtle, Nora, with a tracker on her back. Photo: Madeleine Smitham
« We know they leave nesting beaches as little turtles and we know they come back when they’re adults, but we have very little data about where they move in between, » Ms Hall said.
The trackers are glued to the turtle’s shell and connect to satellites when the animals surfaces. The data has revealed fascinating insights into the locations and distances sea turtles travel.
They discovered Green turtles like to stay close to the coast, feasting on sea grass beds between Wollongong and Port Stephens.
Marine debris removed from Green turtles. Photo: Madeleine Smitham
One Green turtle, nicknamed Nora the Explorer, meandered along the east coast, swimming nearly 1000 kilometres in 147 days.
But the critically endangered Hawkesbill appear to be more adventurous. One turtle, named Kurnell, left the coast line to chase warmer waters. Over 100 days he swam more than 3000 kilometres in a big loop around the Pacific Ocean, often swimming against the current.
Ms Hall said many people assume sea turtles just ride the world’s oceans as passive hitchhikers on strong currents, but tracking has found this isn’t the case.
« They’re actively feeding in the upwelling and not just floating around in the currents, » she said.
« That film Finding Nemo has a lot of answer for, » she jokes.
The tracking project is funded by Woolworths, which donates funds from selling reusable shopping bags.
« It’s not just plastic bags, it’s balloons and plastic wrapping that cause all sorts of problems, » said Ms Hall.
Abandoned fishing line and hooks are also a major threat to sea turtles.
The six tracked turtles have each been lovingly rehabilitated by the hospital staff after receiving life-threatening injuries caused by marine debris.
Turtles often mistake bright coloured plastic for jellyfish or sponges. The plastic then blocks their gut and they starve to death.
« It’s so awful, » she said.