DELRAY BEACH, FLA., AUG. 23 -- With the toll of endangered baby sea turtles mounting, the city has done what wildlife officials asked it to do more than six months ago. Street lights blamed for the deaths were extinguished.

City Manager David Harden ordered the blackout along the beachfront Wednesday after another group of hatchlings wandered onto State Road A1A instead of into the ocean.

Fifteen tiny turtles were killed Tuesday night, even as turtle experts from around the state converged on the beach. They are searching for clues to explain why more than 100 baby turtles have wandered away since Saturday.

"There's a tremendous number of factors to consider," said Blair Witherington, a University of Florida doctoral candidate who has studied sea turtles extensively. "We don't know exactly what's happening but something's wrong."

The disorientations are particularly perplexing because they occurred after special, low sodium lights were installed to prevent turtles from wandering onto the busy highway.

While researchers do not understand exactly what attracts the hatchlings to the ocean, they know it has something to do with lights, Witherington said. It is thought that the moon serves as a beacon for the turtles. However, in modern times, the beacon has become manmade lights that lead turtles to the highway.

He and turtle recovery officer Barbara Schroeder applauded Harden's decision to turn off the lights until Oct. 30, when the six-month turtle nesting season ends. Schroeder and officials from the U.S. Fish and Wildlife Service have been asking the city to dim the lights since last fall when an estimated 200 turtles were killed on the highway.

The city's failure to accept that advice may result in it being charged with violating the Federal Endangered Species Act. Dean Freeman, a federal wildlife officer, said he would probably charge the city with violating the act after an estimated 50 hatchlings were killed on July 20. Fines could reach $100,000.