Shark fin sellers in Hong Kong have been hiding their delicacy away from prying eyes on rooftops, sparking outrage from environmentalists.

Except for a few species, shark-fin selling is legal in Hong Kong but activists have been campaigning about the process of catching the sharks.

Often, when they are caught, their fins are harvested and then they are thrown back into the sea and left to die.

More than 10,000 fins were filmed on a rooftop in Hong Kong, as sellers try to dry out the controversial product away from public areas.

There are fears sharks are being overfished and because they are the apex predator in the sea, this can have a dramatic effect on the ocean’s ecosystem.