Italy’s cruise liner tragedy turned into an environmental crisis on Monday, as rough seas battering the stricken mega-ship raised fears that fuel might leak into pristine waters off Tuscany that are part of a protected sanctuary for dolphins, porpoises and whales.

The ship’s owner accused the jailed captain of causing the wreck that left at least six dead and 29 missing, saying he made an “unapproved, unauthorised manoeuvre” to divert the vessel from its programmed course.

Earlier, authorities had said 16 people were missing. But an Italian Coast Guard official, Marco Brusco, said late Monday that 25 passengers and four crew members were unaccounted for three days after the Costa Concordia struck a reef and capsized off the coast of the tiny island of Giglio.

He didn’t explain the jump, but indicated 10 of the missing are Germans. Two Americans are also among the missing.

Mr. Brusco said there was still “a glimmer of hope” there could be survivors on parts of the vast cruise liner that have yet to be searched. The last survivor, a crewman who had broken his leg, was rescued on Sunday.

Waters that had remained calm for the first days of the rescue turned choppy on Monday, shifting the wreckage and raising fears that any further movement could cause some of the 1.9 million litres of fuel on board to leak into the waters off Giglio, which are popular with scuba divers and form part of the protected Tuscan archipelago. Rescue operations were suspended for several hours because of the rough seas.

Italy’s environmental minister raised the alarm about a potential environmental catastrophe. “At the moment there haven’t been any fuel leaks, but we have to intervene quickly,” the minister, Corrado Clini, told RAI state radio.

Even before the accident there had been mounting calls from environmentalists to restrict passage of large ships in the area.

The ship’s operator, Costa Crociere SpA, has enlisted one of the world’s leading salvagers, Smit of Rotterdam, Netherlands, to handle the removal of the 290-meter cruise liner and extract the fuel safely. Smit has a long track record of dealing with wrecks and leaks, including refloating grounded bulk carriers and securing drilling platforms in the aftermath of Hurricane Katrina.

Meanwhile, the Italian cruise operator said Capt. Francesco Schettino intentionally strayed from the ship’s authorised course into waters too close to the perilous reef, causing it to crash late Friday and capsize.

The navigational version of a “fly by” was apparently made as a favour to the chief waiter who is from Giglio and whose parents live on the island, local media reported.

A judge on Tuesday is to decide whether Mr. Schettino should remain jailed.

“We are struck by the unscrupulousness of the reckless manoeuvre that the commander of the Costa Concordia made near the island of Giglio,” prosecutor Francesco Verusio told reporters. “It was inexcusable.”

The head of the U.N. agency on maritime safety said lessons must be learned from the Concordia disaster 100 years after the Titanic rammed into an iceberg, leading to the first international convention on sea safety.

“We should seriously consider the lessons to be learned and, if necessary, re-examine the regulations on the safety of large passenger ships in the light of the findings of the casualty investigation,” said Koji Sekimizu, secretary-general of the International Maritime Organisation.

More In: International | News