The International SeaKeepers Society worked with the United States Geological Survey to study coral bioerosion on Vigilante. During the expedition, researchers dived several reefs off Islamorada, FL. Specific coral heads that had been previously measured more than 10 years ago were revisited. At each site scientists measured the change in height of the dead coral heads and used this to calculate the amount of erosion occurring on these reefs. Currently the causes for erosion are not fully known. Hypotheses include fish feeding, increased sedimentation and turbidity on the reef, and tourism activities.