South African environmental authorities sent DNA samples from thousands of shark fins confiscated at Cape Town harbour this week for testing yesterday as part of an illegal hauling probe.

Marcel Kroese, head of law enforcement at the country's Marine and Coastal Management agency, told Reuters that officials wanted to establish whether threatened species of fish were involved.

"First of all we want to see where the investigation is going and what charges will be laid," he said.

Marine officials raided premises on Monday and confiscated more than five tonnes of dry shark fin.

Sharks have been declining alarmingly across the world as their fins have become prized, particularly in Asia where shark fin soup is a delicacy. Kroese said virtually all of the sharks thrown back into the sea after their fins were hacked off would have died.