The U.S. Coast Guard is searching for three college students who didn't return from a trip to the Florida Everglades.

Petty Officer Mark Barney tells The Associated Press that the Florida International University students had been collecting water samples in Everglades National Park on Wednesday, and the students didn't return from their trip about 8 p.m.

The Coast Guard was notified Wednesday night and a helicopter crew searched for them. The search resumed Thursday morning.

Barney says the students were in an 18-foot to 23-foot Mako boat.

The Coast Guard says the students' names and ages and other details were not immediately available.