Cut the glow to let turtles go!

“Blinded by the light, Revved up like a deuce, Another runner in the night” (Bruce Springsteen 1973 a true cheesy classic!) Ever experienced that feeling when you suddenly go from a dark room into a blinding bright light room…? It blinds and disorientates you doesn't it! It’s the same for hatchlings as they make their way from the darkness of their nest onto the blazingly lit beach from properties. Once they have struggled to survive through incubation, hatching and emerging, these poor little guys become disorientated by the light. Heading away from their natural cues of the stars and moon light reflecting off the water, up into beach front properties or worse onto the main roads. Eventually if not found in time they will become dehydrated and die, if a vehicle or animal doesn’t get to them first. 

However, it is not only the hatchlings that are impacted, but the nesting females are also having a hard time with increased light spillage onto the beaches. Each year egg-bearing females are abandoning the urge to nest on lighted beaches. Some may even not even emerge from the water. If they do, some females can become disorientated and like the hatchling mis-orientate [A2] into properties where they become susceptible to illegal take and can become entrapped in garden vegetation or swimming pools.

So what can you do to mitigate these threats? Stick with me and we can see what we can do!

Firstly let’s check out the general principles of light pollution:

Wavelength: Go back to your GCSE or O-Level physic years looking through a prism and remember how the light is split into the spectrum. Turtles are most attracted to short wavelengths (violet/blue) of light probably due to the marine environment filtering out the long wavelengths. Turtles are least attracted to longer wavelengths (yellow/orange – red) at the other end of the spectrum. Moonlight falls under the short (violet/blue) wavelength and this became the environmental guidance cue for adults and hatchlings to find their way back to the ocean. White light is composed of many different wavelengths, and has a greater violet/blue wavelength, thus attracts the turtles away from the dull glow from the moon and stars reflecting on the water and toward artificial lights on land. 

Intensity: Alongside wavelength the intensity of the light plays an important role in the turtle’s responses to light. Even Low intensities of short wavelengths cause an orientation response in hatchlings, whereas much higher intensities of long wavelength lights are required to create a similar response. 

Glow: The reflection of the light from clouds, surrounding buildings and vegetation can also be a disruption to turtles. Remember it is not only direct light from a light source that attracts turtles, but indirect light can also attract their attention. For example, when the moon is largely covered by cloud the surrounding glow from the will become the brightest attraction and mis-orientate the hatchlings. 

Direction and Elevation: Directivity is the difference in the brightness of one direction over another. For hatchlings as this light field increase[A6] , the brightest direction becomes more pronounced causing the hatchling to orientate towards the bright light. Bright, low [A7] short wavelength sources can be very disruptive. If the light source is close to the ground it becomes brighter due to the amount of glow reflection and overwhelms the light reflecting off the water’s surface again causing mis-orientation of hatchlings. This is also true by lights mounted on walls where the light is reflected of the surrounding surfaces.

Solution: Turtle Friendly lighting (Cue fan fair!) is a variety of lighting options that are designed to fully meet the lighting needs for beach front properties without impacting turtles. It can be very cost effective and flexible. For example, planting vegetation in front of lights, using long wavelength (amber/red) light bulbs, lowering and shading lights, replacing selected lights with turtle friendly fixtures, and most simply splitting lights onto separate switches so specific problematic lights can be turned off. Not only can these methods benefit the turtles but turtle friendly lighting can also be very beneficial to your wallet! The majority of bulbs are LED and the fixtures are universal so bulbs can be replaced with normal lights out of season, and in places like Florida, they have seen a 70% reduction in energy costs… Tempted much?!

So in summary:

1)      Keep it OFF – Keep lights off the beach and keep them off when they are not needed especially around turtle nesting and hatching season

2)      Keep it LOW – Mount fixtures as low as possible to minimise light trespass, and use the lowest amount of light needed for the task

3)      Keep it SHIELDED – Fully shield the light so bulbs and glowing lenses are not visible from the beach and avoid light escaping upwards and outwards

4)      Keep it LONG – Use long wavelength light sources (ambers and reds) in the appropriate light fixtures

So that’s some food for thought! The next time you find yourself on a beach at night just take a look around and think where would an emerging hatchling go? We decide which way they travel, so let’s make the right choice for them!

Until the next time you lovely people

Luc J