Sediment plumes created by the activity of clam harvesting boats at Bombay Reef, April 11, 2019.
Sediment plumes created by the activity of clam harvesting boats at Bombay Reef, April 11, 2019. CSIS AMTI/Maxar Technologies

A new feature by CSIS’s Asia Maritime Transparency Initiative uses satellite imagery to document renewed illegal Chinese clam harvesting in the South China Sea. The practice has damaged at least 25,000 acres of reef, further endangering a critical ecosystem in a region already faced with collapsing fish stocks. Clam harvesting also serves as an additional example of the Chinese using resource exploitation as a means of supporting its illegal territorial claims in the region and will increase tensions between China and the Philippines.

After a sharp drop-off in activity from 2016 to late 2018, Chinese clam harvesting fleets have returned to the South China Sea in force over the last six months. These fleets, which typically include dozens of small fishing vessels accompanied by a handful of larger “motherships,” destroy vast swaths of coral reef in order to extract endangered giant clams. The clam shells are transported back to Hainan Province where they fetch thousands of dollars each in a thriving market for jewelry and statuary. Since late 2018, satellite imagery has shown these fleets operating frequently at Scarborough Shoal and throughout the Paracels, including at Bombay Reef.

From 2012 to 2015, Chinese clam harvesters severely damaged or destroyed at least 28 reefs across the South China Sea, as documented by Victor Robert Lee. The typical method employed by these poachers involved anchoring their boats and then dragging the reinforced props of their outboard motors across the reef surface to break up the coral, allowing the clams to be easily lifted out. The ecological results were devastating, and, as a result, in July 2016 the arbitral tribunal that ruled on a case brought against Beijing by Manila found that China had violated its obligations under international law to protect the marine environment. John McManus at the University of Miami, who submitted expert testimony to the tribunal, documented more than 25,000 acres of damage to shallow reef surfaces as a result of Chinese clam extraction as of 2016 (compared to roughly 15,000 acres damaged by dredging and landfill activities to create China’s artificial islands).

Now, as then, Chinese authorities are aware of and appear to condone the activities of these fleets. Satellite imagery shows that clam harvesting boats have been operating with regularity at Bombay Reef in the Paracel Islands since late 2018, as evidenced most clearly by the sediment plumes visible in images from April 11. Those plumes, along with the scarring spread across the reef surface, are the telltale signs of the prop-digging method of extraction used during the earlier phase of clam harvesting. And this is occurring despite China’s installation of an “Ocean E-Station” on Bombay Reef last July. The documented surveillance capabilities of this platform suggest that it is relaying information about all activity near the reef to Chinese authorities in the Paracels, yet the clam harvesting continues unabated.

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