A Friday yacht excursion for seven people and their pets ended in a U.S. Coast Guard rescue when the craft began to take on water, Berkeley Fire Chief Gil Dong said.

All seven aboard the yacht were fine and no medical treatment was required, Dong said. Also OK were a dog, cat and snake that also were out for the ride.

The yacht was just outside the Berkeley Pier when it began taking on water about 12:30 p.m. Friday. Officials don't know what caused the incident.

Rescue boats pulled along the craft and safely evacuated several aboard.

Five people were returned to the Berkeley Marina, while two others remained with the yacht while the Coast Guard towed the boat to the Emeryville Marina, Dong said.

Officials did not identify the seven people onboard nor did they give the name of the yacht. The 32- to 40-foot yacht was about 300 feet north of the Berkeley Pier when water began enter the vessel, Dong said.

Rick Hurd covers breaking news. Contact him at 925-945-4780 and follow him at Twitter.com/3rdERH.