MANILA (Reuters) - Filipino fishermen say their livelihoods are under threat from skirmishes with Chinese ships on prime fishing grounds in the South China Sea.

Local fishermen say Chinese ships are heavily patrolling key fishing areas of the South Chinsa Sea, after Beijing built artificial islands and military installations.

China seized the Scarborough shoal from the Philippines four years ago, but the country's new President Rodrigo Duterte says he will never give up his country's rights to the rocky reef.

The ongoing dispute can mean scary confrontation for fishermen like Nelson Plamiano. "The Chinese watch us through their telescopes and approach us as we get close to the shoal. Their boats surround us and try to squeeze us in. They hit us with their water canons and shoo us away," he said.

The Philippines has filed a case against China at the Permanent Court of Arbitration in Europe, seeking a ruling on its right to exploit the water. A decision is expected early next week, although China has already made it clear it will ignore the outcome.

Meanwhile, Filipino fishermen will be heading out to their traditional fishing waters, hoping to catch more than just another fight.