For migrant workers trapped onboard Chinese distant water fishing fleets, cutting the fins off sharks as they writhe violently on rusted decks in the Indian Ocean isn’t accidental. It’s an intentional and lucrative act that marks the start of a bloody half-a-billion-dollar offshore supply chain, tacitly supported by Beijing yet covertly concealed from port inspectors globally.

The Center for Biological Diversity, a nonprofit focused on the protection of endangered species, filed a formal petition this month requesting the U.S. government potentially sanction China for failing to meet American shark conservation standards. Shark populations have declined by more than 70 percent since 1970, with more than one-third of all shark and ray species now threatened with extinction. Yet each year, Chinese-flagged vessels catch, brutally fin and discard thousands.

Should the National Marine Fisheries Service identify China as having violated the U.S. Moratorium Protection Act, then President Trump could be expected to ban the import of all $1.5 billion of Chinese seafood.

“Losing sharks wouldn’t just be an ecological disaster; it would be a profound moral failure,” Alex Olivera, a senior scientist at the Center for Biological Diversity, said in an email. “Sharks have survived for hundreds of millions of years, and it would be a tragedy if they disappeared in a few decades because governments failed to enforce basic conservation rules.”