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I have a friend who lives in Orlando, Florida. She and her husband are avid sailors and travelers. They also hunt lighthouses, and have seen over 100 different ones. They're currently on a trip from Florida up the Eastern Seaboard all the way to Nova Scotia.

She's been seeing signs on some beaches in Florida and North Carolina prohibiting the use of artificial lights after 9:00 pm. This includes beach boardwalk lights, headlights, streetlights, and even house lights for people who live on the waterfront. These are mainly in areas where turtles breed.

Why would these rules be in effect?

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The Sea Turtle Conservancy (STC) gives two reasons for keeping beaches dark at night when sea turtles are laying or hatching.

The first reason the STC gives is that a nesting turtle likes quiet, dark beaches. If she cannot find such a spot after several attempts, she will choose a less than ideal spot to lay her eggs, and perhaps even lay them in the ocean. This reduces the probability of survival for the hatchlings.

Having been liberally splattered with sand by a turtle laying in broad daylight (Aldabra Atoll, the Seychelles) as one of a ring of observing tourists (quiet and motionless tourists), I personally put greater emphasis on the second reason given by the STC.

Lighting near the shore also can cause hatchlings to become disoriented and wander inland, where they often die of dehydration or predation. Hatchlings, scientists believe, have an innate instinct that leads them in the brightest direction, which is normally moonlight reflecting off of the ocean. Excess lighting from the nearshore buildings and streets draw hatchlings toward land, where they may be eaten, run over, or drown in swimming pools.

I'd welcome more expert opinion on the sensitivity of nesting females to light. The adult turtles I have encountered seem phlegmatic, but maybe inside they are nervous. Also, I am perhaps reading too much into the behavior of the Aldabra Atoll turtle. Aldabra Atoll has only a small research station and very few visitors -- it is as unlike a Florida seaside community as any place on Earth.

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    @Sue What we saw was a turtle. It dug its nest in the sand on the beach in full and intense sunlight, and then went to the lagoon and swam away, to our cheering. "The major difference between the two is that tortoises dwell on land, while turtles live in the water some or nearly all of the time." Turtle vs Tortoise. – ab2 Jul 13 '17 at 20:26

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