Conservation group Sea Shepherd has claimed victory after a four-month pursuit of the toothfish poaching vessel Thunder

Anti-poaching group Sea Shepherd are claiming victory in a four-month pursuit of an illegal fishing vessel, which came to a sudden end in the Southern Ocean.

Thunder sank off the coast of São Tomé earlier this month after all 40 poachers abandoned ship into a series of liferafts.

This dramatic episode signalled the end of the 11,533-mile chase, which is believed to be the longest on record.

Capt. Peter Hammarstedt, who was on board Sea Shepherd’s vessel MV Bob Barker at the time of the sinking, believes that it was an intentional act of sabotage.

“Usually when a vessel is sinking, the captain will close all hatches so as to maintain buoyancy,” he explains.

“However, on the Thunder, the reverse was done – doors and hatches were tied open and the fishhold was opened. It is an incredibly suspicious situation, to say the least.

“We have cost the poachers millions of dollars in lost profits and have sent a very clear message to those that remain: poaching will not be tolerated in the waters of Antarctica.”

Sea Shepherd had been pursuing Thunder since December as part of their Operation Icefish campaign to crack down on toothfish poaching in the Southern Ocean.

In an attempt to escape their pursuers, the crew of Thunder jettisoned 72km of illegal fishing gear on Christmas Day, which was later retrieved by Sea Shepherd’s MV Sam Simon.

illegal fishing gear

The crew of MV Sam Simon retrieved 72km of illegal gillnets – Photo: Giacomo Giorgi

The confiscated gear, which included gillnets, was handed over to the relevant authorities in Mauritius, and this prompted Interpol to issue its first ever Purple Notice against a fishing vessel.

The chase finally came to an end on Friday April 10, when all 40 poachers were successfully rescued from their liferafts using Humber Ocean Pro 6.3m RIBs and later handed over to the São Tomé and Príncipe coastguard.

To watch the sinking of poaching vessel Thunder, click on the video above.