A British-flagged cruise ship damaged more than 18,000 square meters (4.4 acres) of coral when it ran aground in waters popular with divers off Indonesia’s eastern province of Papua, government officials said on Wednesday.

The 3,800 tonne-Caledonian Sky was carrying 102 passengers when it entered shallow waters at the beginning of this month in Raja Ampat in West Papua and had to be towed back out to sea.

The area is known for its biodiversity, diving and pristine beaches, but is largely untouched by the mass tourism seen in destinations like Bali.

A joint team from the government and the ship’s insurance company surveyed the location for damage to the coral reef and were calculating economic losses, said Arif Havas Oegroseno, deputy coordinating minister for maritime affairs.

“Both parties have concluded that the total coral reef damaged area is 18,882 square meters,” he added.

Much of the damaged area - the size of around 70 tennis courts – was not salvageable, Oegroseno said.

Ship owner Salen Ship Management, a Swedish company, was not immediately available for comment.