Unfortunately we have had a significant impact on turtles over time. Here in Australia turtles were hunted mercilessly for their shells and meat by colonial sailors who used the meat as a long-lasting source of food when making long journeys between islands. Turtle soup was also once a booming export industry.
The shell of the hawksbill turtle is prised for making ornaments and jewellery and though hawksbill products were banned internationally in the 1990s, the illegal trade continues and new demand has recently re-emerged.
Even though turtles are now protected they still face considerable threats from human actions.
Artificial lighting discourages the majority of nesting females from coming onshore. Turtle hatchlings use light and reflections from the night sky to find their way to the water following the light horizon. Artificial lighting on nesting beaches cause confusion and disorientation to sea turtle hatchlings and results in them heading in the wrong direction. Unfortunately this is likely to result in hatchling death due to dehydration and increased exposure to predators.
Turtles often congregate in the same areas as commercially valuable fish and can be prone to becoming bycatch—this refers to the inadvertent capture of non-target animals in fishing gear.
The leading cause of sea turtle deaths in the last 50 years has been commercial fisheries bycatch. They mainly become trapped in shrimp trawls, gill nets, and longline fishing gear.
Turtles aren’t the only animals prone to bycatch. The WWF estimates that 300 000 whales and dolphins, 300 000 seabirds and one million sharks make up the one and a half million animals effected each year.
An abandoned fishing net carrying 17 dead sea turtles discovered off the coast of Bahia, Brazil days after a storm. Image by Projeto Tamar Brazil via Marine Photobank.
Warming sea temperatures could cause sea turtles to head further South in the search of suitable nesting sites, and are also contributing to more frequent natural disasters which, coupled with rising sea levels, threaten to flood or totally erode traditional nesting sites.
Warmer seas and higher temperatures can also result in higher sand temperatures which can result in nest mortality.
Vehicles such as Beach cleaning tractors and other 4WD drivers can crush nests and compact the sand, making it very difficult for the hatchlings to emerge.
Deep tyre tracks in the sand can create a trap for the hatchlings, preventing them from reaching the ocean, making them easy targets for predators and exposing them to high temperatures and dehydration. It is important to be concious of this when driving on the beach, and to always avoid driving accross the dunes, unless you are using a designated track.
Turtles also face threats from water vehicles such as boats, jet-ski’s and other watercraft. They are particularly vulnerable since they like to move slowly across the surface and when coming up for air. Boat strike is very common in Moreton Bay as it is a major feeding area for six of the seven species of sea turtles. It’s important to be aware of ‘go-slow’ zones in national marine parks to keep sea turtles, other marine life and yourself safe.
Thousands of tons of rubbish is dumped into the oceans every day around the world putting all marine life under significant threat.
Sea Jelly make up a big portion of turtles’ diets and they often mistake floating plastic for jellyfish and consume it, resulting in sickness, bloating and death.
Microplastics also cause sickness due to accidental consumption, it is estimated that there are 5.25 trillion tiny particles of plastic floating in the ocean and they are readily consumed by many species, including humans through consumption of seafood.
Injuries from entanglement are also common with abandoned fishing lines being the main culprit. Abandoned fishing line impacts a wide-range of marine species and is a leading cause of injury and death.
While you are out walking why not do your bit for the turtles and other marine life by picking up rubbish as you go? By picking it up and disposing of it responsibly, you are helping create a safe environment for everyone.
If every beach goer picked up three items of rubbish every time they visited the beach, collectively we would make a huge impact.
Turtle nests and hatchlings are naturally predated upon by lace monitors, crabs and native birds. Upon reaching the Ocean, many will also become food for fish and other sea creatures. This is a natural process and is all part of what was once a well-functioning ecosystem.
Unfortunately, eggs and hatchlings are now vulnerable to a range of none native species such as feral pig, foxes and cats. Feral pigs and foxes will actively hunt for and excavate the nest, eating all the eggs.
Out of control pet dogs (off leash, domesticated animals) also pose a significant threat to eggs and hatchlings. Most dog owners are all-round animal lovers and do not intend for their pets to harm sea turtles but owners should make sure to keep their dogs within their sight on the beach, just incase there are hatchlings around, and should prevent their dogs from digging in the dunes.
Humans can potentially have a big impact on turtle nests and hatchlings, especially on the Gold Coast due to it’s constant exposure to coastal development.
The increase of hotels, parking lots and housing along beaches can threaten nesting behaviours. Turtle hatchlings usually time their crossing of the beach to be on or after high tide, in the light of the full moon. In a natural situation they would be traversing over sand that is relatively undisturbed and had been compacted by the tide, enabling their entry to the water to be swift. When there is high foot traffic the hatchlings may be navigating their entry to the water through a minefield of footprints and other sand disturbances. In addition to the disturbed sands, they may also be dealing with light pollution sending them the wrong direction, and also beach users themselves who might shine lights at them, pick them up, further disturb the sand, or worse.
The longer hatchlings are out of their nest and not in the water, the lower their chance of survival is as they’re at risk for dehydration, exhaustion, predators, and anthropogenic threats. All these factors mean that the hatchlings are on the beach for much longer than they should be. This gives the sand time to dry out and become less stable, and for the tide to go back out making their journey much longer.
Items such as umbrellas, discarded beach toys and even sandcastles can hinder their journey. When using these items, especially umbrellas, avoid the dunes as umbrellas can penetrate nets killings individual eggs and beach toys and sandcastles can add extra obstacles.