SANIBEL-CAPTIVA CONSERVATION FOUNDATION

It’s sea turtle hatching season on Sanibel and Captiva. While adult turtles are laying their final nests of the year, many nests are beginning to hatch, and thousands of hatchlings are starting their journey out into the Gulf of Mexico.

Since June, 5,812 hatchlings had emerged on the islands (5,772 loggerhead and 40 leatherback), and a total of 793 nests had been laid this season (790 loggerhead, two green turtle and one leatherback).

With so many hatchlings trying to find their way to sea, artificial lighting poses a significant threat.

WHY ARTIFICIAL LIGHTS ARE A THREAT

While adult sea turtle females find their way to their natal beaches to lay eggs using magnetic signatures from Earth’s electromagnetic field, multiple studies have suggested that fewer nests are laid in areas of the beach where there are higher levels of artificial lights.

SANIBEL-CAPTIVA CONSERVATION FOUNDATION Naturally, sea turtle hatchlings navigate the critical journey from nest to sea by using the reflection of the night sky off the water. Artificial lights interfere with the process and may lead to confused hatchlings moving in the wrong direction or sometimes in circles, as pictured by these tracks.

Historically, suitable nesting beaches are often backed by vegetation and dune structures, which create a shadowed, darker horizon. Once emerged from the ocean, nesting sea turtles may continue to crawl inland along the sand in the direction of this dark horizon.

For hatchlings, it’s a reversal of this concept. Sea turtle hatchlings emerge from the nest at night, and one of their cues to finding the ocean revolves around orienting to the brightest point on the horizon, which would naturally lead them in the seaward direction.

WHEN ARTIFICIAL LIGHTS ARE INTRODUCED

Artificial lights disrupt an environment’s natural lighting, which at night are determined by factors like moonlight and cloud cover.

For nesting females, the presence of artificial lights may deter them from coming ashore or crawling further up a beach to nest. This could be due to the seaward direction now appearing darker than artificial lighting from an inland source. If a female fails to nest after multiple attempts, she will eventually resort to a best-case scenario of nesting in a sub-optimal area or, at worst, depositing the eggs in the ocean where they will not survive.

CITY OF SANIBEL

For hatchlings, artificial lighting can create a miscue and draw them landward, away from the ocean.

Hatchlings that are disoriented and head toward these lights may never make it to the water. They can end up overexerting themselves crawling away from the ocean and can end up in dangerous places such as parking lots, roadways, and pools. In addition, the longer the hatchlings are on land, the more susceptible they are to terrestrial predators.

WHAT YOU CAN DO TO HELP

For those in beachfront residences, turn off lights at night or close blinds on windows so that interior light does not emanate out onto the beach. Exterior lights should be sea turtle-friendly devices and bulbs.

Sea turtle-friendly lights often produce a long wavelength — red or amber/orange. Red light emits a narrow portion of the visible light spectrum, and sea turtles are not as disrupted by them. This greatly dampens the effect of the artificial light and is less disruptive to the natural light field, allowing for turtles to navigate by the appropriate, natural cues.

Also refrain from using flashlights or cell phone lights while on the beach in the dark. Many nights, the natural light provided by the moon is enough to comfortably see. If you would like the assistance of an artificial light, such as a phone or flashlight, use a sea turtle-friendly red light or red filter.

To report stranded turtles or issues related to nests, lighting, beach furniture or holes on the beach, contact the SCCF Sea Turtle Hotline at 978-728-3663.

Lighting violations can also be reported to the Sanibel Police Department at 239-472-3111, Sanibel Code Enforcement 239-472-4136 or Sanibel Natural Resources at 239-472-3700.

For more information about wildlife-friendly lighting, visit https://conserveturtles.org/beachfront-lighting-turtle-friendly-fixtures-lights/.

For more information about certified wildlife lighting, visit https://myfwc.com/conservation/you-conserve/lighting/criteria/certified/.

For more information about Sanibel’s lighting ordinance, visit https://library.municode.com/fl/sanibel/codes/code_of_ordinances?nodeId=SPBLADECO_CH126ZO_ARTXIVSUDIRE_DIV4OULI#TOPTITLE.

For more information about sea turtle disorientation, visit https://myfwc.com/wildlifehabitats/wildlife/sea-turtle/lighting/disorientations/.

For more information about the “After 9, it’s turtle time campaign,” visit https://www.mysanibel.com/departments/natural-resources/protecting-our-beaches/sea-turtles.