the sea turtle project

I had two ideas: the first was identification and mapping of lighting code violators, to notify them about turning their lights off at night. 

The second was a bit flakier… and was inspired by Amber’s description of loss of dunes, and the trend towards building taller houses, hotels, and other beach front developments resulting in sea turtle misorientations.

If the lighting code was not effective in changing behaviors… maybe there was a way to reduce the amount of light reaching the entrance of the nest. A screen of some type.

Two things were in my favor: I knew Sea Turtle Patrol tracked the nests, plus there’s a physical change in the sand above the nest entrance about ten days before hatching… you’ll see a depression in the sand that looks like a bowling ball had rested there. So, we wouldn’t have to shield every nest, we could target those most at risk which are getting ready to hatch. The second: besides being an engineer and a problem-solver, I also have sewing and design skills… and happened to have the perfect material on hand for this particular challenge: Pfifertex mesh screen fabric.

It gets windy on the beach, so I figured a mesh screen would be less likely to be blown over, ripping poles out, than one made from solid fabric. I used a light meter to measure the reduction in light transmitted by this mesh, and it was ~ 70%. I figured that might be enough to tilt the odds in the baby sea turtles’ favor.

My first idea was to build a large PVC frame, but that would require staking… and be very prone to getting blown over. Finally, the day before we left to return home, I came up with the idea of something smaller that could be attached directly to the nest poles already in use. I needed some data, so I walked down to the beach, tape measure in hand, and measured pole heights and side lengths for four nests. I figured that was enough to give me a feel for the variation in data of the nests… I’d watched Sea Turtle Patrol volunteers measure where to place the poles during the two nest relocations, so I knew it wasn’t random!

I still had to figure out dimensions for making the prototypes, and how to attach them to the poles… currently 1 PVC pole and two bamboo poles were being used, with caution tape  wrapped around. The simplest idea would be to have a sleeve on each end that could slide over the end poles. I was also trying to figure out how to optimize the use of the mesh material, which is 54″ wide… not quite as long as I wanted. But since it’s a game of angles (and the taller the item, the longer the shadow it will cast), I didn’t want to take it down to 27″ high… it can be a long walk to the ocean at low tide for a baby sea turtle. I was shooting for something closer to 36″.

I decided to try out my rapid prototyping skills, and built a PVC frame using the same diameter PVC as the nest poles. I thought orange mesh would be best for the screens – more visible. I mocked up a quick prototype to check my idea for attachment options around the center PVC pole with the warning signs – velcro one wrap cable ties stitched onto the mesh at different distances from the top and bottom. I was not sure about dimensions and attachment options, and wanted to get input from Amber before going further. I figured the first step would be to make a prototype and install it on a dummy nest to be sure it was stable.

When I reached out to Amber, she arranged a Zoom call for us to talk. The great news… although we were unsure how effective my idea would be, she said they had lots of PVC poles they could use for the other two sides, no need to worry about velcro tabs to reach around the caution tape. A simple sleeve that could slide over the end poles would work, and make everything so much easier to attach, remove, and store later. 

Above left is a photo of my first prototype, showing baby turtle tracks headed in the right direction (towards the ocean!) and not the houses behind it.

Not only did Amber Kuehn get approval from SC Department of Natural Resources to use it, but it worked! She even got funding for me to make 30 more nest screens for use this year–2022. The new screens are royal blue.

I’d like to thank all the Sea Turtle Patrol volunteers who graciously answered my questions and helped to educate me while they worked, especially Kym, Carol, Skylar, and Lauren. I’d also like to thank the Turtle Trackers who tirelessly patrol the beach, fill in sand pits, etc. to make it safe for our sea turtles, and who help organize the Turtle Talks I attended at Dunes House. Special thanks to Turtle Tracker Becky who introduced me to Amber, and also shared some of her photos and videos. You don’t have to be a full-time resident to be a Turtle Tracker and help!

If you’d like to help sea turtles on Hilton Head, please consider donating to Sea Turtle Patrol or Turtle Trackers! Sea Turtle Patrol HHI also offers nest dedications.