The son-in-law of Tunisia's deposed former dictator Zine El Abidine Ben Ali has been arrested in the Seychelles, the Tunisian authorities announced on Friday.

Sakhr El Materi, who was convicted in absentia for corruption by a Tunisian court, fled to Qatar after the mass uprising that toppled his father-in-law in January 2011, but the Gulf emirate agreed to expel him in September this year.

Seychelles and Germany have the healthiest seas of any inhabited territory, while Sierra Leone has the unhealthiest, according to a new index that says many oceans score poorly for biodiversity and as a human resource.

Topping the list with a score of 86 out of 100 was the uninhabited South Pacific territory of Jarvis Island, owned by the United States, as well as a clutch of other unpopulated Pacific Ocean islands.

Madagascar's President Andry Rajoelina and ousted leader Marc Ravalomanana left the Seychelles Thursday, after failing to strike a deal in talks aimed at ending three years of political crisis.

"The former president Marc Ravalomanana has left the Seychelles this morning by a commercial flight," a Seychelles government official said, adding that Rajoelina left shortly after.

Madagascan leader Andry Rajoelina and the man he toppled in 2009, Marc Ravalomanana, met Wednesday on a remote Seychelles island to force a breakthrough in reconciliation efforts.

"The face-to-face talks between the Madagascan transitional president and his predecessor began this morning on the island of Desroches," a Seychelles government official said.

Opposition radio Free FM has stopped broadcasting due to intimidation by Madagascar's military in the wake of a weekend mutiny, station manager Lalatiana Rakotondrazafy told Agence France Presse on Tuesday.

"We won't resume broadcasting until I am sure that there will be no more intimidation," she told AFP.

Mauritius and the Seychelles on Tuesday signed a pact to jointly manage a continental shelf in the Indian Ocean spanning 396,000 square kilometers in what was described as a path breaking accord.

The pact came after the two island nations obtained conjoint rights on the Mascarene Islands continental shelf in March last year. The treaty was signed during a visit by Seychelles President James Michel.

Passengers on the crippled Italian liner Costa Allegra Thursday said they thought they would have to get into lifeboats and abandon ship in pirate-infested waters when it was disabled by fire.

"When it all happened we were ready to get into the lifeboats. We thought the worst had happened," said Chris, one of more than 600 passengers who stepped gratefully ashore in the Seychelles capital after a three-day ordeal.

A U.S. drone crashed Tuesday at Seychelles international airport on the main island of Mahe, the U.S. embassy said.

The remote-piloted MQ-9 aircraft crashed on landing but no one was hurt, said the U.S. embassy in Mauritius, which also handles the Seychelles. The drone was operating from the Seychelles, it said.