At least 87 passengers in a high-speed ferry have been injured in an apparent collision with a marine animal off a Japanese island, according to coastguard officers and local media reports.Thirteen people suffered serious injuries in the accident on Saturday, which occurred as the vessel was heading to Sado island, public broadcaster NHK quoted the Japan coastguard as saying.It is likely the ferry hit a whale, as both humpbacks and minkes are often found in the area, NHK quoted a marine wildlife expert as saying."It was a huge impact," a passenger told the broadcaster. "One person was bleeding." There was damage to the back of the vessel, local media said. A 15cm crack was found at the ferry's stern. However, the ferry - with 121 passengers and four crew on board - reached its destination on the island, located off the west coast of Japan's main island of Honshu without outside help, local media said.