Reduction of lights in coastal community helps conservation of sea turtles in Guanacaste

by | Feb 15, 2006

15 of February 2006 – San José, Costa Rica

During the 2005 nesting season, the public street lights in San Miguel, Guanacaste, were modified to benefit the populations of sea turtles that nest in the area.

Light contamination on beaches as a result of human development negatively affects sea turtle nesting.   Adult sea turtles avoid nesting in illuminated areas and therefore lose significant nesting habitat where bright lights line the beach.  Light contamination also disorients turtle hatchlings that emerge from their nests at night because they are attracted towards the lights.  Instead of heading towards the sea, the newly hatched turtles head inland, making themselves more vulnerable to death from overexertion, dehydration, and depredation and to being run over by vehicles.  The disorientation of adults and hatchlings during these critical stages of their lifecycle further worsens the already critical situation facing sea turtles.  

San Miguel, Guanacaste, is a small coastal community where hundreds of sea turtles nest each year and where PRETOMA has been conducting a sea turtle monitoring and conservation project since 1998.  The ecological integrity of San Miguel as a sea turtle nesting beach was recently threatened by light contamination as a result of public street lamps, which were unnecessarily illuminating the nesting beach during the night.

PRETOMA, in conjunction with the community of San Miguel, which is dedicated to protecting the environment and sea turtles and believes that local development can be accomplished in a sustainable manner, solicited the Costa Rican Electrical Institute (ICE) to install shields on the public street lamps that would direct light toward the ground and not toward the beach and in this way minimize the problem of the lights.

ICE responded swiftly and on the November 23, 2005 installed shields on 22 lamps along the entire main street of San Miguel parallel to the beach.

At 8:30 p.m. on December 7, 2005, just two weeks after the shields were installed, a leatherback sea turtle nested at San Miguel.  Quickly, various members of PRETOMA and the community gathered around to watch the amazing visitor.  Pacific leatherback turtles, which have decreased 95% over the last 20 years, are considered the most endangered population of sea turtles in the world.

Regarding the nesting event, PRETOMA’s Beach Projects Coordinator Ingrid Yañez commented, “Whether the arrival of the leatherback is a result of the installation of the shields we’ll never know, but the timing of the nest is very coincidental.”

On February 8, 2006, the community of San Miguel, employees of ICE and PRETOMA representatives met to get feedback from the community regarding the shields, which resulted in complete support of their installation.

“The town is a bit darker, but it’s just a matter of getting accustomed, I remember when there wasn’t any light at all,” said San Miguel community member Dominga Ch