A high-speed ferry collided with an unidentified object, possibly a whale, in waters off Kagoshima Prefecture on Sunday evening, leaving at least 104 passengers injured, 36 of them hospitalized, the Japan Coast Guard and the ferry's operator said Monday.

The Toppy-4 ferry, with 109 passengers and crew members on board, was heading from Yaku Island to the city of Kagoshima when the incident occurred 3 km west of Cape Sata at 6:05 p.m., coast guard officials said.

The ferry was traveling at 80 kph.

All of the crew members were injured.

The ship was towed to the port of Yamakawa, Kagoshima Prefecture, and an investigation into the collision is under way, according to the officials.

Three patrol ships and a coast guard helicopter started searching the area where the accident occurred to look for any floating objects, such as the body of a whale. "A whale-like marine animal hit the rear part of the ferry's port side and the vessel leaned forward," an official from the vessel's operator, Kagoshima Shosen, quoted Kyoichi Akase, captain of the ferry, as saying.

The impact was so strong that the ferry was disabled.

At the time of the incident, the ferry was transmitting a special sound underwater that whales dislike in an effort to keep them away from the vessel, according to Kagoshima Shosen.