Experts have determined that a second turtle found dead on O'ahu's North Shore was struck by boat propellers. Preliminary reports suggested shark bites on the animal's flippers but it was more likely advance stages of decomposition, said George Balazs, head of the Turtle Research Program for the National Oceanic and Atmospheric Administration.

"There's no evidence whatever of a shark attack," Balazs said. "The turtle has been hit by a boat. Of course we never know at this stage of decomposition if the turtle was hit by the boat first and died or if it died from some other unknown cause and then was hit by the boat."

The large carcass was reported to NOAA on Sunday. It was collected, examined at the turtle research laboratory at the University of Hawai'i at Manoa and disposed of Sunday, Balazs said.

It was the second turtle found dead on the North Shore over the weekend. A green sea turtle was discovered at Laniakea Beach near Hale'iwa on Saturday. That turtle apparently was killed by a person or persons for its meat.

Balazs said there was no evidence of butchering or human tampering on the decomposed turtle carcass.