Jetties a safe haven for predators

Jetty in South Perth. Photo: Eliza Lyon.

A new study has found turtle hatchlings are more likely to be eaten by predators when entering open waters close to jetties.

PhD candidate at the University of Western Australia and lead author of the study Phillipa Wilson said this was due to predators of the hatchlings using the structure as a “day time refuge”.

According to Ms Wilson the study focused on what are the two main impacts on marine turtle hatchlings: artificial light and coastal development.

“As jetties are often lit and we know that turtle hatchlings are attracted to light … we wanted to know how this might affect turtle hatchlings as they swim away from the shoreline,” Ms Wilson said.

Co-author of the research study Dr Kellie Pendoley said the findings were different to what they had expected.

“[Instead] it was this amazing finding about fish predation. [It was a] classic scientific study with serendipitous results,” Dr Pendoley said.

Fish and turtles on Thevenard Island. Video: Australian Institute of Marine Science.

The study found 70 per cent of the tagged turtles they released onto the beach encountered predators in the nearshore zone.

The team of scientists from UWA, the Australian Institute of Marine Science, the Department of Biodiversity, Conservation and Attractions and Pendoley Environmental conducted this study in north Western Australia on Thevenard Island.

Ms Wilson said usually when sea turtles left the shoreline, they quickly swam away from the beach.

However, when conducting this study the trackers attached to the turtles showed the reptiles had never left the area.

“We found a lot of them started swimming parallel to the shoreline and also back and forth from this jetty and it was at that point we realised we were no longer tracking turtle hatchlings, but we were actually tracking fish, that had eaten our turtle hatchlings with the tags on them,” Ms Wilson said.

Dr Pendoley said we need to consider where jetties in WA are located and if they are near turtle nesting beaches.

Phillipa Wilson discusses her study.