More than 80 passengers were reported injured, several seriously, after a hydrofoil ferry apparently struck a whale while underway in the Sea of Japan on Saturday.

The high-speed hydrofoil, named Ginga, was underway from Niigata, Japan to Sado Island when the vessel struck what the ferry operator said appears to be “marine life”.

The impact was strong enough to send passengers flying into seats in front of them.

The operator, Sado Steam Ship Company, said there were 121 passengers and four crew members on board at the time. Six people were transferred to a hospital with serious injuries, the company said in an apology.

The vessel arrived at Sado Island under its own power but about an hour behind schedule.

The waterjet-powered Ginga ferry has a top speed of 46 knots, according to the operator’s website.