Around 200 tonnes of illegally harvested giant clam shells worth nearly $25 million (£18 million) have been seized in the Philippines. The seizure is one of the largest ever hauls of the endangered species. Four suspects have been arrested on an island in the ecologically protected province of Palawan. Giant clams can grow larger than one metre across, and weigh up to 250kg. They are seen as vital to the local marine ecosystem. The Philippines is home to most of the world’s giant tropical clam species.