Satellite imagery taken on March 23 from Maxar Technologies shows Chinese vessels anchored at the Whitsun Reef, a feature in the Spratly Islands in the South China Sea. Photo: AFP
Mark J. Valencia
Mark J. Valencia

South China Sea: why report on Chinese boats dumping sewage doesn’t hold water

  • The report concludes too much based on remote sensing, without confirming its findings with on-site observation
  • The suggestion that damage to the coral threatens the food security of coastal states is based on unproven assumptions about the Spratlys as a genetic ‘savings bank’
I really have to hand it to the China bashers. The latest allegation that Chinese fishing boats are dumping raw sewage in Philippine waters is a clever attempt to stir anti-China feelings in the Philippines.
It also bolsters the opposition to Philippine President Rodrigo Duterte’s more congenial approach to China ahead of next year’s elections. Right on cue, Senator Grace Poe said the “stinking reality” is that China is treating the Philippines “as its toilet”.

However, the allegations cry out for close examination. According to the report by US-based satellite spectral analysis firm Simularity, sewage from groups of anchored Chinese fishing boats in Philippine waters have caused algal blooms that damaged coral reefs and therefore endangered coastal states’ fisheries.

Liz Derr, a co-author of the study, said the team compared recent satellite images of the reefs with ones taken in 2016 and found a significant increase in areas that appeared white – those covered in chlorophyll-A – and a decrease in dark areas, which lacked chlorophyll.

Derr warned there could be a decline in fish stocks, an important regional food source, because schools of fish, including migratory tuna, breed in the affected reefs.

A slide from Simularity’s presentation showing ships (left) and concentration of chlorophyll-a (right) on June 17. Photo: Handout

Philippine officials were sceptical. Referring to the report’s use of a 2014 photo from the Great Barrier Reef, Foreign Secretary Teodoro Locsin Jnr said the country “can’t and should not do foreign policy on the word of a liar in part who is likely a liar in whole. It is just not done.”

The report also concludes too much based on remote sensing. The Union Banks are 34 miles long and up to 9.3 miles wide, a fairly large area when one is analysing from space the cause and effect of pollution from a single source.

Chinese boats are not the only ones dumping raw sewage. Most fishing boats operating in the Spratlys do so. They also probably dump other waste.

This is in addition to the waste from inhabitants of the reefs. In the Spratlys, 21 features are occupied by Vietnam, nine by the Philippines, eight by China (including Taiwan) and five by Malaysia.


The South China Sea dispute explained

The South China Sea dispute explained

The study raised concerns about the release of waste by ships anchored on reefs. According to Derr, this would be a violation of international and Chinese law that stipulates its ships may release sewage only when they are moving at a speed of at least four knots.

Sewage and garbage from the boats may well have damaged the environment of the waters that China and the others claim, and the pollutants and their effects may have spread into Philippine exclusive economic zone waters – a violation of international law. But this remains to be proven by “before and after” on-site observation and sampling using control sites for comparison.

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It is not proven that waste from these ships was the only contributor to the algal bloom. Other factors, like overfishing, dynamite and poison fishing, could also be at play.

Derr said, “To rule out other factors that may be causing this overgrowth, such as climate change or rising ocean temperatures, Simularity looked for but could not find unoccupied reefs for comparison.” But speculation based on satellite images should be proven on the ground before making such public accusations.


Philippines sounds alarm over 200 Chinese ships in the South China Sea

Philippines sounds alarm over 200 Chinese ships in the South China Sea

Further, proving that pollution damaged the Spratly ecosystem requires on-site research to confirm cause and effect. After-the-fact confirmation will be difficult.

But the real leap of faith is the claim that the ecosystem damage will threaten the livelihood of coastal state fishers and food security. This is based on the theory that the Spratlys ecosystem is a main habitat for larvae that repopulate heavily fished waters elsewhere.

The originators and supporters of this theory call the Spratlys a genetic “savings bank.” But there is no proof that this theory applies to the main target fisheries in the South China Sea. The Spratlys could just as well be a semi-isolated ecosystem harbouring and nurturing mostly indigenous coral reef fish larvae.

China, the Philippines and a missed opportunity in the South China Sea

Some studies have indicated “a very strong gene flow between the offshore reef in the Spratly Islands and near shore reefs in the northwestern Philippines” for starfish and boring clam. But another study found two genetically distinct groups of rabbitfish indicating reproductive isolation and thus limited gene flow in the area.

As proponents of this theory, such as Dr Fernando Siringan, director at the University of the Philippines-Marine Science Institute, stated in 2019, monitoring and research is needed to strengthen the hypothesis of a significant connection between the disputed features and Filipinos food security. That is still true today.

The region’s coastal waters play a major role in nurturing fish larvae for capture fisheries. Long-term unrestrained mangrove destruction, reclamation, pollution and overfishing are the predominant causes of the decline of the main capture fisheries in the South China Sea.

An aerial image, taken from a Philippine Air Force plane on April 21, 2017, shows Chinese construction in the Subi Reef in the South China Sea. Photo: AFP

Chinese construction and fishers “mining” of giant clams have destroyed many coral reefs in the Spratlys. Other claimants have also engaged in construction on features they occupy.

Long before these environmental depredations, fishers – particularly from the Philippines – engaged in very destructive muro ami, blast and poison fishing there. Pollution from passing ships has also been a factor.

China has initiated a programme to restore the coral reef ecosystem in the Spratlys. Other claimants that have undertaken construction on the features should follow suit.

If this controversy stimulates more awareness, and preventive and remedial action, that is to the good. But the allegations themselves remain largely unproven.

Mark J. Valencia is an adjunct senior scholar at the National Institute for South China Sea Studies, Haikou, China