Sonic blasts used in oil exploration pose a mounting threat to whales, especially a critically endangered species that feeds and breeds near Russia\'s Sakhalin Island, the global whaling forum has heard. Britain and the United States voiced fears that plans to build a third oil and gas platform near the Pacific island could affect a species called the Western gray whale, delegates at the International Whaling Commission (IWC) meeting said. \"The United Kingdom is deeply concerned that ongoing industrial activities around Sakhalin Island continue to pose a threat\" to the whale population, said junior environment minister Richard Benyon. Belgium said 12 countries had written to Moscow, urging it to pressure the Sakhalin Energy Investment Corporation to postpone an upcoming seismic survey. In mid-2010, three such exploratory forays were conducted in the area despite pleas to wait until Western gray whales had finished their migration there. \"There may be fewer than 130 Western gray whales remaining, and the loss of just one or two breeding females each year could lead these whales to extinction,\" said Wendy Elliot, head of the WWF delegation at the IWC. Used to detect subsea oil deposits, seismic surveys require shooting large pulses of sound into the ocean floor. Shockwaves can disrupt the ability of whales to feed or communicate and -- if the sea mammals are too close -- cause tissue damage, scientists say. \"During prospection, ships criss-cross the ocean using compressed air canons that deliver massive sound blasts vertically, penetrating 20 kilometres (12 miles) beneath the ocean floor,\" explained Michel Andre, director of the Laboratory of Appplied Bio-Acoustics in Barcelona. For cetaceans within a range of two to three kilometres (one to two miles), the blasts can have a devastating impact, \"including death\", he said by phone. Environmentalists say the depletion of onshore oil has accelerated offshore exploration using sonar blasts. Other problems are caused by the less forceful but continuous drone emitted by oil and gas platforms, said Andre, who has designed systems to temporarily idle industrial operations when whales are detected nearby. The combined impact of commercial shipping, military sonars and oil exploitation means that \"there is not a single corner of the oceans that is truly free of noise, resulting in a kind of \'acoustic smog\'\", Andre said. For the Western gray whales, there is clear evidence that they have been driven from their preferred feeding grounds in the past by noise from hydrocarbon platforms, said Justin Cooke, a scientists at the International Union for the Conservation of Nature (IUCN) and a member of the IWC Scientific Committee. \"The concern is that if their feeding is disrupted, their reproductive success will be lessened. We are dealing with a population of less than 150 animals, of which about 30 are reproductive females,\" he told AFP. Since 2004, the IUCN had worked with Sakhalin Energy, a joint subsidiary of Shell and Gazprom, on how to minimise noise impacts, and is set to make formal recommendations. \"It seems to be the only place where there is this kind of cooperation between industry and an organisation like the IUCN,\" an umbrella environmental network grouping more than 1,000 government and NGO organisations. The four-day IWC meeting in Jersey, on the British Channel Islands, winds up on Thursday.