China has significantly ramped up its efforts to block Philippine access to Bajo de Masinloc, also known as Scarborough Shoal, over the past year, according to the security think tank SeaLight.

In a virtual forum organized by the Stratbase ADR Institute on Tuesday, SeaLight's director and former US Air Force officer, Ray Powell, said the organization’s ship tracking data has detected a more than twofold increase in automatic identification system (AIS) broadcasts from China Coast Guard (CCG) and Chinese maritime militia (CMM) vessels near the shoal between May 2024 and April 2025, compared to the same period the previous year.

Between May 2023 and April 2024, SeaLight tracked 57 China Coast Guard (CCG) and Chinese maritime militia (CMM) vessels transmitting approximately 724,000 AIS signals near Bajo de Masinloc.

In the following 12 months, however, the "area of intense activity expanded dramatically," with 78 ships generating around 1.57 million broadcasts — more than double the previous year’s total.

Powell also observed that the Chinese vessels dispersed in all directions, with a particularly notable concentration heading east toward the Philippine mainland.

“The main takeaway is essentially the doubling of Chinese activities in Scarborough Shoal in the last 12 months and the fact that they continue to push further and further east,” he said.

“Transmissions [broadcasts] mean the particular transmission from a particular ship on its AIS system. We measure transmissions to indicate the overall activity in that area,” he added.

In response to China’s ongoing activities, Powell said the Philippines has ramped up its vessel deployments and patrols near Bajo de Masinloc.

From May 2023 to April 2024, Philippine AIS data showed a modest seven vessels from the Philippine Coast Guard (PCG) and the Bureau of Fisheries and Aquatic Resources (BFAR), producing 55,000 AIS broadcasts around Bajo de Masinloc.

However, from May 2024 to April 2025, AIS broadcasts surged to 217,000 from 11 ships — an increase of nearly four times.

Despite this uptick, Philippine vessels have not yet reached the shoal itself.

“The PCG and BFAR ships have been extremely active and busy in asserting Philippine rights. There was a quadrupling of activities,” Powell said.

“The situation is not because the Philippines has not been making a valiant effort to assert its rights. It’s simply being overwhelmed by the sheer volume of Chinese ships. The Philippines continues to make its case in a visible way," he added.

Meanwhile, National Security Council (NSC) Assistant Director General Jonathan Malaya stated that the Philippines will continue to assert its sovereignty and jurisdiction over the shoal, despite having fewer vessels than China.

Malaya lamented the potential dangers posed by China's actions, particularly their "dangerous maneuvers" in the disputed area.

He stressed that despite the potential risks at Scarborough Shoal, the Philippines is prepared to face them, as the shoal is recognized as Philippine territory.

"The risk to our servicemen [is] there. But it is a risk worth taking because, clearly, the shoal belongs to us and we must fly the flag and stand for international law,” Malaya said.

"We have been doing this, but the challenges are there. Notwithstanding those challenges for and behalf of our fishermen, the territory and integrity of the Philippines, we will continue to ramp up this presence by sending our ships regularly for maritime patrols, as well as air patrols to fly the flag and send a strong message that we will not be deterred in asserting our rights and jurisdiction in Bajo de Masinloc,” he added.

Further, Malaya noted that the increasing and persistent presence of Chinese ships in the area has restricted Filipino fishermen’s access to the shoal.

“It’s the effect on our fishermen who have been traditionally fishing in this area for a very long time and have been curtailed significantly,” he said.