Last month, the National Task Force on the West Philippine Sea, an interagency body housed within the Presidential Office in Manila, reported that more than 200 Chinese militia vessels were anchored at Whitsun Reef. The task force released photos of some of those vessels, collected during a patrol by the Philippine Coast Guard on March 7. Additional images and video were released after two subsequent patrols by the Philippine Coast Guard ship Cabra. As with other known militia deployments, the behavior of these vessels defies commercial explanation. Most have remained in the area for weeks or even months, riding at anchor in clusters without engaging in any fishing activity. Many are trawlers which, by definition, must move to fish. And blue skies have debunked the initial excuse from the Chinese Embassy in Manila that they were riding out a storm.

AMTI has identified 14 of the ships in these photos and videos. To these can be added the vessels of the Yuetaiyu fleet, numbered 18000-18999. Those nine ships have broadcast AIS from Whitsun several times, as previously reported by Andrew Erickson and Ryan Martinson. Their involvement in the militia has been well-documented and AMTI first tracked them patrolling Union Banks, which includes Whitsun Reef, in early 2019.

A photo taken during the initial Philippine patrol on March 7 shows six Chinese vessels tied together at Whitsun Reef. Only the bow numbers and the first two characters, Yue (粤) and Mao (茂), of five of the ships can be clearly seen. By cross referencing this information with vessel profiles in the commercial AIS database Marine Traffic, AMTI can identify them as the Yuemaobinyu (粤茂滨渔) 42881, 42882, 42883, 42885, and 42886.

These names will sound familiar in the Philippines. In early 2019, the Yuemaobinyu 42212—so named because it operates from the same port as these five—rammed and sank the Philippine fishing vessel F/B Gem-Ver 1 at Reed Bank. AMTI afterward discovered that the vessel had a history of government contracts and suspicious AIS activity, but could not conclusively prove that it was part of the militia.

Video shot during the Cabra’s first patrol on March 26-27 provides a clear shot of another vessel, the Yueyangxiyu (粤阳西渔) 96523:

Also visible is a vessel with the bow number 08041—almost certainly the Yuezhanyu (粤湛渔) 08041. That conclusion is supported by both AIS data from Marine Traffic and the later identification of its sister ships, the Yuezhanyu 08039, 08042, and 08043 in a video shot during the Cabra’s recent return visit on April 12-13.

This second video also captured the Yuexinhuiyu (粤新会渔) 60138 and 60139, which Andrew Erickson and Ryan Martinson recently profiled in Foreign Policy.

Another photo from that April 12-13 patrol shows two more vessels: the Yuexiayu (粤霞渔) 90122 and another Yuezhanyu-series vessel whose number begins with 0804. This appears to be the Yuezhanyu 08040, which AIS shows sailed out of port in Zhanjiang with its sister ships in late February.

The available AIS data for the 23 vessels so far identified at Whitsun Reef confirms what their names already indicate—they are based out of a small number of ports in Guangdong Province. Each vessel’s name begins with “Yue” (粤), a shorthand for Guangdong, and ends with “Yu” (渔), meaning fish. In between are characters referring to their homeports.

The “Zhan” (湛) in “Yuezhanyu”, for example, shows that they operate out of Zhanjiang. So does the Yuexiayu 90122, where “Xia” (霞) refers to Xiashan District in Zhanjiang. Following this same logic, the Yueyangxiyu 96523 operates out of Yangxi County, which is under the control of Yangjiang. The Yuexinhuiyu fleet is based in Xinhui District, Jiangmen, and the Yuetaiyu fleet in Taishan. The “Maobin” (茂滨) in Yuemaobinyu is short for Maoming Binhai New Area, which in 2012 was established as a subdivision of Dianbai District in Maoming. That led to these vessels being renamed from “Yuedianyu” to “Yuemaobinyu.”

Besides the Yuetaiyu fleet, none of the vessels broadcast AIS signals from Whitsun Reef strong enough to be picked up by satellite. They are all equipped with weaker Class-B AIS transceivers and can only be detected by shore-based transceivers. As a result, the last any of them were seen by commercially available AIS trackers was leaving port in January and February headed south. The Yuemaobinyu 42882, for instance, left Bohe Harbor on January 11, followed by the 42881 and 42885 on January 26. The Yueyangxiyu 96523 left Puyuzhou Bay on February 19. The Yuezhanyu 08041 left Zhanjiang on February 20 and the 08040 did the same on February 27. The Yuexinhuiyu 60138 and 60139 sailed out of Jiangmen together on February 24.

Pulling Back

The Philippine government’s response to the surge in militia vessels at Whitsun has drawn attention to the area. But Chinese boats did not just start gathering there over the last few months. Satellite imagery from Planet Labs shows that significant numbers of vessels have been at Whitsun since at least February 2020—a fact earlier reported by Radio Free Asia.

(counterclockwise from top left) February 27, 2020; September 22, 2020; March 25, 2021

The number of vessels at Whitsun has fluctuated over this period, but never entirely disappeared. It is also misleading to view the number of ships at Whitsun in isolation. The reef is just the eastern end of a larger geological structure in the Spratlys called Union Banks, which falls within the exclusive economic zone (EEZ) claimed by the Philippines. Other parts of Union Banks are occupied by China (Johnson and Hughes Reef) and Vietnam (Sin Cowe Island, and Collins, Grierson, and Lansdowne Reefs). Chinese vessels appear to frequently bounce between Whitsun and other parts of Union Banks, such as unoccupied Kennan Reef next to the Chinese base at Hughes. To get a better sense of this pattern, AMTI counted the total number of vessels visible in satellite imagery of Union Banks, including Whitsun, since February 2020.

Limited visibility due to cloud cover makes this an incomplete count, including on those days in February and early March when the Philippine Coast Guard documented more than 200 vessels at Whitsun. It also includes some Chinese and Vietnamese coastguard and navy vessels, as well as Vietnamese fishing boats. But the vast majority are Chinese fishing vessels 50 meters or more in length, which distinguishes them from their smaller Vietnamese counterparts. The data shows that China has sustained a militia presence at Whitsun for more than a year. And the militia has been patrolling Union Banks in general for at least the last two years, as evidenced by the activity of the Yuetaiyu fleet.