Ever since he was a teenager, Filipino fisherman Rony Drio has been sailing into the heart of the South China Sea to fish at the Scarborough Shoal, a large atoll rich in fish stocks that has become one of Asia’s most contested maritime features.

But now, 56-year-old Drio said, it has become increasingly difficult and dangerous to fish at the atoll – some 200 km (124 miles) off the Filipino coast – because of aggressive action by China, which claims the disputed shoal.

Filipino fishermen in San Salvador Island in the Masinloc municipality told Context that China was using speedboats and water cannon to block access to an area that is inside the Philippines exclusive economic zone (EEZ) but was seized by China in 2012.

The skirmishes are taking place as the Philippines steps up its defence posture in the South China Sea, an area long seen as a potential flashpoint between the United States and China.

The high seas drama has slashed the incomes of the fishermen of San Salvador Island. No longer able to fish freely at the atoll, and sometimes chased away before they have even caught anything, they are forced into the open sea.

This costs more in fuel, leading many into a vicious cycle where each trip leaves them more indebted and thus forced to travel further next time to catch more fish.

The Scarborough Shoal is named after a British ship that was grounded here in 1748 but is known to Filipinos as Bajo de Masinloc or Panatag — a Tagalog word for “peaceful”.

An international tribunal invalidated China’s claim to 90 per cent of the South China Sea in 2016 but Beijing does not recognise the ruling. Since it seized the shoal in 2012, it has maintained a constant deployment of coast guard and fishing trawlers.

The Chinese embassy in Manila did not immediately reply to requests for comment on this story.

There was some respite for Filipino fishermen after Rodrigo Duterte came to power in Manila in 2016 and relations with China improved. Fishermen were allowed back to the shoal but tensions have mounted since Ferdinand Marcos Jr, who has forged closer ties with Washington, became president last year.

Pamalakaya, a national alliance of fishermen, said fishermen in Zambales province have lost around 70 per cent of their income because of restrictions on access to the shallow, bountiful waters of the Scarborough Shoal.

The Philippines’ Bureau of Fisheries and Aquatic Resources (BFAR) said the South China Sea is an important fishing ground for over 385,000 registered fishermen, contributing a total of 304,000 metric tons of fish from 2018 to 2022.

A study last year by the Peoples Development Institute (PDI), an NGO focusing on asset reform and rural development, found that fishing at Scarborough Shoal before 2012 could yield up to three tons of various high value species per fishing trip.

But it is now becoming “economically unfeasible” to fish in the area due to dwindling catches, destruction of coral reefs, harassment by Chinese vessels, and inclement weather, with fishermen unable to shelter in the shoal, the study said.

It also said China was destroying the coral reef at Scarborough through giant clam digging operations, in which coral reefs are pulverised to gather the clams underneath.

The fishermen are also taking action. In 2020, more than 1,000 fishermen in Zambales and nearby provinces formed the Bigkis Fisherfolk Federation to defend their freedom to fish on the shoal.

“We formed a group because our pleas had fallen on deaf ears before. We were ignored,” said Henrelito Empoc, a Masinloc fisherman and the group’s spokesperson.

Empoc said the group has urged the government to adopt a more assertive approach to reclaim and manage the country’s EEZ. They also want the government to permanently deploy Filipino coast guards on the Scarborough Shoal and create alternative livelihoods for struggling fishermen in Masinloc and elsewhere.

The BFAR says it has created an 80-million-peso livelihood project for fishermen and also conducts resupply missions to fishing boats in the West Philippine Sea, providing engine oil, drinking water, and snacks to those out on the water.