The military’s Western Command (Wescom) recently showed photos of a large number of Chinese vessels swarming around two uninhabited features in the Reed Bank area, where the Philippines was exploring oil-and-gas resources.

The Western Command regularly sends a Philippine Navy light plane, a Brittan Norman islander, to patrol the disputed South China Sea, increasing its maritime domain awareness and watching China’s activities and movements in the strategic sealanes.

Based on its monitoring, the Western Command reported that there were at least 48 Chinese fishing boats circling around Iroquois Reef (Del Pilar) and Sabina Shoal (Escoda) in the South China Sea during the last week of June.

There were also three Chinese coast guard vessels and two People’s Liberation Army (PLA)-Navy warships roaming in the same areas.

China clearly violated the country’s sovereignty because the two features are within the Philippines’ 200-nautical-mile exclusive economic zone (EEZ).

The Chinese vessels appeared to be stationary and were not conducting fishing activities. Their presence in the Reed Bank is a serious threat to oil-and-gas exploration in the area.

The Coast Guard spokesman, Jay Tarriela, expressed concern the Chinese might occupy Iroquois Reef.

Iroquois Reef, a feature submerged during high tide, lies east of Philippine-occupied Nansha island (Lawak) and Flat island (Patag) in the disputed Spratly chain of islands.

Sabina is near where BRP Sierra Madre had run aground on Second Thomas Shoal (Ayungin), the closest Philippine-occupied feature to Palwawan.

Tarriela’s fears about China occupying Iroquois Reef could be unfounded. But it controls the waters around the reef – another way of taking possession of the uninhabited feature. It will still be a violation of the Philippines’s sovereign rights.

China will not literally occupy a submerged feature unless it will build another artificial island.

If China decides to create another man-made island in the Reed Bank area, Beijing will be violating the 2002 agreement, the Declaration on the Conduct of Parties in the South China Sea (DOC), signed in Phnom Penh. It prohibits new occupation of uninhabited features in the South China Sea.

In fairness to Beijing, the seven man-made islands it had built in the Spratly chain of islands were long occupied by China. It appeared China did not transgress the DOC, but the excessive reclamation and island building violated the principles of the DOC.

China’s swarming tactics in the South China Sea began two years ago when it deployed about 200 vessels around Whitsun Reef (Julian Felipe), a boomerang-shaped uninhabited feature in the Union Banks.

The following year, Chinese vessels in smaller numbers returned to Whitsun Reef, claiming the area by virtue of controlling the surrounding waters.

This year, China has become bolder by sending a large number of vessels in the Reed Bank, around Iroquois Reef.

If the Chinese vessels were observed to be conducting fishing activities, it would be more damaging to the country because China could be draining resources exclusively reserved for the Philippines.

China’s fishing methods were also known to be excessive and destructive, as fishermen use cyanide and other banned chemicals as well as illegal methods.

However, the real purpose of the massive presence of Chinese fishing and militia vessels around Iroquois Reef is to stop the Philippines from unilaterally conducting oil-and-gas exploration in the area.

In 2011, Chinese patrol vessels harassed an oil exploration vessel hired by an Anglo-Filipino company to look for commercially viable oil and gas reserves in the Reed Bank.

The incident was among the reasons the Philippines went to the Permanent Court of Arbitration in The Hague in 2013 to seek an international ruling on the country’s economic rights on the South China Sea.

In July 2016, the arbitration court ruled in favor of the Philippines, repudiating China’s excessive nine-dash-line claim on the South China Sea.

It awarded the Philippines full economic rights on the Reed Bank area under the 1982 United Nations Convention on the Law of the Sea (Unclos).

China is a signatory to Unclos but refuses to recognize the arbitration ruling.

By deploying a huge number of fishing and militia vessels in the Reed Bank, China was preventing the Philippines from exploring the area.

It would be difficult to conduct oil and gas exploration if Chinese fishing boats get in the way.

China was probably sending a strong message to the Philippines – partner with China’s National Offshore Oil Corporation.

China does not want the Philippines to partner with other countries in the oil-and-gas exploration in the Reed Bank. It wants a share in the oil-and-gas exploration project in the area.

China will probably remove the huge number of fishing boats in the Iroquois Reef once the Philippines agrees to a joint exploration deal.

During the term of President Rodrigo Duterte, the Philippines had a joint exploration deal with China.

But there was no progress in the joint exploration deal. Duterte decided to terminate it.

The Philippines only wasted time, money and effort because China does not really want the country to extract energy resources in the Reed Bank.

The Philippines is desperately seeking new oil-and-gas wells in the disputed waters.

Its only known source – Malampaya – is fast driving up. It may last up to 2029.

Under the new government, Ferdinand Marcos Jr was in favor of resuming oil and gas exploration in the Reed Bank unilaterally. He was also ready to send coast guard ships to escort survey vessels hired by a private consortium that won service contracts in the Reed Bank.

China has responded by sending a huge number of fishing and militia vessels, backed by the coast guard and its navy, to areas where the Philippines planned to explore oil and gas resources.

China’s swarming tactics in the South China Sea does not only seek to control the disputed sea. It cannot occupy new features but it could sent dozens of vessels to control the sea around disputed features in the South China Sea.

But the swarming tactics could be a deliberate message to the Philippines – do not explore unilaterally in Reed Bank.