text: Environmental activists rescued 40 crew from a sinking ship it suspected of conducting illegal fishing near the island of Sao Tope, off the Gabon coast. The Nigerian-flagged Thunder was being tracked by activists from the charity Sea Shepherd, who believed it was engaged in illegal fishing. The Thunder's captain and crew manned life rafts late on Monday after the ship was scuttled. Scroll down for video . Rogue fishermen are believed to have scuttled this ship, Thunder from Lagos to cover up illegal fishing . Charity Sea Shepherd had been tracking the Thunder for the past 110 days off the west coast of Africa . The fishing vessel sank in perfect conditions, leading to suspicions that it had been deliberately scuttled . Sea Shepherd's vessels Bob Barker and Sam Simon rescued the men from the ocean. The Thunder had been fishing in the waters between Sao Tome and Principe, off the west coast of Africa. Bob Barker's captain Peter Hammarstedt said: 'It is an incredibly suspicious situation, to say the least. 'When my chief engineer boarded the Thunder in the hours leading up to the sinking, he was able to confirm that there were clear signs that the vessel was intentionally scuttled. 'Usually when a vessel is sinking, the captain will close all hatches so as to maintain buoyancy. However, on the Thunder, the reverse was done - doors and hatches were tied open and the fishhold was opened.' Sea Shepherd said the crew were given food and water and were transferred to Sam Simon. Video recorded by the activist group showed the ship sinking just hours after it said Thunder issued a distress signal on Monday afternoon. The Thunder's crew of 40 all managed to escape into life rafts before the vessel sunk to the ocean bottom . Members of Sea Shepherd launched rescue boats to rescue the members of crew from the ocean . Watertight doors on board the Thunder were dogged open increasing suspicion that the vessel was scuttled . Hammarstedt said Thunder's captain, who was not named, complained about being rescued and 'started applauding and cheering' when the vessel sank. He told the Sydney Morning Herald: 'We've been chasing the Thunder for 110 days now, and I think they're basically at the end of their fuel, and they would have had to make a port call . 'I think the captain of the Thunder made the decision that he preferred the physical evidence on board... was better on the ocean bottom than going into port with him.' Thunder, on a list of boats deemed to have engaged in illegal, unreported, or unregulated fishing activities by multi-national body the Conservation of Antarctic Marine Living Resources (CCAMLR), is suspected of illegal fishing for Patagonian toothfish and other rare species in the Antarctic. Toothfish is sold as Chilean sea bass, which is popular in high-end restaurants. It sells primarily in the United States, Europe and Japan, although there is also a growing market in China. Sea Shepherd's vessel Bob Barker, pictured, had been tracking The Thunder for more than 100 days .
target: The Thunder from Lagos was suspected of illegally fishing for Toothfish .
  Sea Shepherd had been tracking the Thunder for more than 100 days .
  The Thunder's captain is suspected of scuttling the vessel in a cover-up .
  Watertight doors were dogged open to allow the vessel to sink faster .