An oil barge sank off southern Spain yesterday with 1'400 tonnes of fuel on board and rescuers found the body of the captain as an oil spill from the ship began to stain the nearby coast of Gibraltar. Salvage teams saved two crew members from the ship, which sank before dawn amid gusting winds and four metre (13 feet) waves as it was being towed toward the port of Algeciras. The ship went down one mile (1.6 km) from the Spanish coast in some 50 metres of water. After helicopters and search boats scoured the choppy bay for several hours, a spokesman for the Spanish maritime authorities said the captain's body had finally been found. With the oil slick from the tanker Prestige still blackening its northwest coast, Spain was quick to react to the threat of a new environmental disaster: throwing booms around the spill and rushing a clean-up vessel to the scene. Our air, land and sea services remain on alert, following the progress of the spill in case it should hit the shore, said Development Minister Francisco Alvarez Cascos, who rushed to the scene. He added that currents were carrying the oil out to sea. Spanish oil company Cepsa, which had contracted the vessel to carry oil from the nearby Gibraltar refinery to the port of Algeciras, said that frogmen had examined the sunken ship and established there were no cracks in its hull. Cascos and local shipping officials said the slick appeared to have come from the ship's engines and not its cargo, minimising the chance of major environmental damage. Witnesses in Gibraltar said the thick diesel oil had already reached the shore and covered a long stretch of coast, where clean-up teams had already begun work to remove it. Port authorities were considering whether to remove the fuel from the ship, owned by Spanish company Ciresa, or try to raise it from the sea floor. It sank in Spanish waters only a day after activists from ecological group Greenpeace boarded a tanker in Gibraltar's waters on the other side of Algeciras bay. The environmental group was protesting against the potential environmental hazard from such ships, which are used to refuel boats as they pass through the straits at the entrance to the Mediterranean. Two Spanish journalists and four activists held in custody overnight after the protest were released on bail yesterday. One journalist was charged with assaulting a police officer. The incident revived diplomatic tensions over the disputed British colony, as Spain's Foreign Ministry called the British Embassy in Madrid to demand a swift release of the detainees. Spain has long claimed sovereignty over the rocky enclave on its southern coast, which it ceded to Britain in 1713 at the Treaty of Utrecht. Negotiations to share sovereignty over the territory stalled last year. Spain suffered its worst-ever environmental disaster in November when the tanker Prestige sank, spilling much of its 77'000 tonnes of toxic fuel oil along the country's northwest coast and unleashing a wave of public anger. Volunteers and officials are still battling to clean the once-pristine coast of Galicia of hundreds of tonnes of thick, foul-smelling fuel oil. Spain's Development Ministry said in a statement that a British clean-up vessel was on its way from Galicia to Algeciras to help remove the spill.