Hundreds of Chinese fishing vessels illegally occupying the Philippines’ Spratly Islands are allegedly dumping vast amounts of human waste into the surrounding South China Sea causing an ecological “catastrophe” that threatens the health of local marine ecosystems and fishing stocks, Reuters reported on Tuesday.

“Swarms of Chinese vessels have dumped human waste and wastewater for years in a disputed area of the South China Sea, causing algae blooms that have damaged coral reefs and threatened fish in an unfolding catastrophe,” Liz Derr, the co-founder and CEO of Simularity Inc., told reporters on Monday.

Simularity Inc. is a software company that creates artificial intelligence (A.I.) technologies for satellite imagery analysis. The U.S.-based company recently published satellite images of Spratly Reef that allegedly show how illegal Chinese fishing fleets “anchored in the Spratlys are dumping raw sewage onto the reefs they are occupying.”

Satellite imagery reviewed by Simularity Inc. indicates that “at least 236 ships were spotted in the atoll … on June 17 alone,” Derr told journalists at a Philippine online news forum discussing China’s illegal actions in the South China Sea on July 12.

“When the ships don’t move, the poop piles up,” Derr said, adding that monster algae blooms caused by the sewage are “so intense you can see [them] from space.”

“This is a catastrophe of epic proportions and we are close to the point of no return,” she warned.

“Schools of fish, including migratory tuna, breed in the reefs that are being damaged,” Derr informed the panel on Monday. She said the unregulated sewage dumping and resultant algae blooms “could cause fish stocks to considerably decline in an offshore area that is a key regional food source.”

Philippine Department of Foreign Affairs Assistant Secretary Eduardo Menez told reporters in Manila on Monday Simularity Inc.’s findings “would have to be assessed and validated by Philippine authorities before a decision on whether to lodge a protest against China could be made.”

“While we are confirming and verifying these wastes being dumped … we consider such irresponsible acts, if true, to be gravely detrimental to the marine ecology in the area,” Philippine Defense Secretary Delfin Lorenzana said in a press release on July 13.

“Despite conflicting claims and interests by states in the South China Sea, all nations must be responsible stewards of our natural resources and environment,” the statement read.

China illegally claims more than 90 percent of the South China Sea, including the Philippines’ Spratly Islands. The Philippine Coast Guard spotted 220 Chinese fishing boats moored near the Philippines’ Julian Felipe Reef — located roughly 95 miles west of the Spratly Islands — on March 7. China’s presence near the reef directly violated Philippine maritime sovereignty, prompting Manila to file a formal diplomatic protest with China on March 22 to recall the fleet. Beijing refused to move the vessels, however, and further insulted the Philippines by claiming sovereignty over Julian Felipe Reef.

While the Chinese fishing fleet appeared to largely disperse from Julian Felipe Reef in subsequent weeks, Manila suspected the vessels remained within the boundaries of the Philippines’ Exclusive Economic Zone (EEZ). According to international law, an EEZ grants a coastal state “sovereign rights for the purpose of exploring and exploiting, conserving and managing the natural resources, whether living or non-living, of the waters superjacent to the seabed and of the seabed and its subsoil.”