The captain and the navigator of a ship that ran aground on a New Zealand reef last year in what authorities have called the country's worst maritime environmental disaster were each sentenced Friday to seven months in jail.

About 400 tons of fuel oil spilled on Astrolabe Reef near Tauranga and at least 2,000 sea birds died in the Oct. 5 grounding of the cargo ship Rena.

Judge Robert Wolff from the Tauranga District Court sentenced the ship's captain, Mauro Balomaga, and navigating officer, Leonil Relon, both of the Philippines. The two had already pleaded guilty to operating the ship dangerously and altering documents after the crash. They had earlier been granted name suppression by the court, but that expired when they were sentenced.

A preliminary report released by transport investigators in March found that the Rena took shortcuts to try to reach port by a deadline.

Maritime New Zealand, the agency responsible for shipping in New Zealand, said it was pleased with the sentences.