Taiwan operates the second largest longline fishing fleet in the world with boats spending months — and sometimes years — crossing remote oceans to supply the seafood that ends up on our supermarket shelves.

But those who work on its vessels — mostly poor migrants from the Philippines, Indonesia and Vietnam — paint a grim picture of punishing work hours, docked pay, months without family contact, regular beatings, and even death at sea.

Last year the United States added fish caught by Taiwan’s deep water fleets to its list of goods produced by forced labour for the first time.