4 Missing Fishermen: Missing Man John Robinson Rescued Off Texas Gulf Coast

Four fishermen were missing Saturday after their boat sank off the Texas Gulf Coast Friday. A fifth fisherman, John Robinson, was rescued by the U.S. Coast Guard Friday.

Robinson told officials he was unsure of the location of the other fishermen, but that he survived by holding onto a life raft. The four other missing fisherman have not yet been identified, the Associated Press reported.

Petty Officer Richard Brahm said the Coast Guard originally received a distress call from the men Friday at around 3:30 a.m. local time, saying that their 50-foot vessel was sinking.

It took the Coast Guard five hours to locate Robinson, a crew member aboard the commercial-fishing boat Nite Owl, NBC News reported.

"They saw a life raft floating. They launched a helicopter, went up there, and there was one guy in the life raft," said Brahm, who added that Robinson was more concerned about his fellow crew members than his own well-being.

The U.S. Coast Guard is using aircraft and surface vessels to search the 2,000-square-mile area where Robinson was found. The cause of the boat's sinking is under investigation.

"The guy that we rescued just said the boat started sinking," Brahm said. "He wasn't sure what caused it."

AP reported the boat sank 115 miles southeast of Galveston.