Monitoring Turtle Loggerhead nesting.

THE Coolum Coast Care turtle group, on Queensland’s Sunshine Coast, has seen the negative effects artificial lighting has on endangered, nesting, Marine Turtles and Turtle Hatchlings first-hand over the past seven years of collecting important turtle nesting data on the Coast.

The group recently attended a Marine Turtle Training day with Dr Col Limpus from the Qld Department of the Environment, and during the training day learnt more about the effects of lighting.

Nesting and Hatchling Marine Turtles are disoriented by bright lights. Artificial lights interfere with their natural habits and instincts, resulting in negative impacts on the population.

Nesting Turtles prefer to nest on dark beaches, and after the hatchlings emerge from their nests at night, they find their way to the sea by moving towards the lightest horizon as they see it.

Under natural conditions, this is over the ocean and hatchlings will quickly travel down the beach into the water, heading for the strong coastal currents to carry them into deeper water where they can mature.

If nesting areas become bright from artificial lights, female turtles are unable to nest in those locations. If a female does nest on a beach with nearby artificial lights, near towns, high-rise developments and resorts, artificial lights can mask a turtle’s capacity to see the natural horizon. Unfortunately in these unnatural situations, hatchlings can become disoriented, veering from their natural path and heading towards the artificial light source, lessening their chances of survival.

It’s important to understand its not just light shining on the beach, but also light shining out onto the ocean that has a negative effect on turtles. Even hatchlings that have made it to the sea can be enticed back to land by strong coastal lights.

As Coolum Coast Care learnt from the talk, a female is deciding upon potential nesting sites from 100m – 200m out in the water, so any light shining out into the water from high rise lighting for example, will deter her from nesting at those locations.

Another issue is the combined glow of lighting, and the glow onto low level clouds, an example Dr Col Limpus gave the group is a Supermarket at Bargara, having carpark flood lighting shining onto white shadecloths creating a glow that is seen kilometers away at Mon Repos beach. Flood lights with shades to direct lights to where the light is needed, black shade cloths, and the light-source not so high would help to minimise the glow.

There are Turtle Friendly Lighting solutions available. During the breeding season from mid-October to April from 7.30pm onwards, you can help endangered loggerhead turtles by turning off any unnecessary internal and external lights, closing your curtains and blinds, using motion sensor or intermittent lights for external lighting, using proven turtle-friendly low-pressure sodium vapour light bulbs for external lighting, positioning your lights so they face away from the beach and planting vegetation buffers to help shield your lights.

Dr Limpus has asked the Coolum Coast Care Turtle Group to add to their data by measuring the angle the nesting turtles are making their way up and down the beach to nest, and the angle the hatchlings are emerging from the nests as they make their way to the waters edge.

This collected data will determine the impact nearby lighting is having on the endangered Sunshine Coast Turtle population. For more information visit: www.ehp.qld.gov.au/wildlife/animals-az/loggerhead_turtle.html and www.coolumcoastcare.org.au.

– Ben Pearce. 

19/01/2014