Plans for an oil platform off Sakhalin in Russia's Far East poses a major threat to an endangered whale population already on the brink of disappearing, a wildlife protection group said.

Sakhalin Energy Investment Company, which is partly owned by Shell as well as several Japanese companies, has announced plans for a major oil platform near the feeding grounds of the Western North Pacific gray whale population, of which only about 130 exist, said WWF-International.

Though a number of oil and gas development projects already exist in the area, construction of an additional off-shore platform could further disrupt feeding and increase the danger of whales being struck by ships, not to mention the potential impact of an oil spill.

"Just around 30 female western gray whales of breeding age remain. The population is already on the brink of disappearing forever," said Aleksey Knizhnikov, oil & gas environmental policy officer for WWF-Russia.

"The loss of even a few breeding females could mean the end for the population."

Gray whales occur on both sides of the Pacific, but the Western population is classified as separate from the Eastern population, with genetic studies showing the two populations probably do not mix, says the International Union for Conservation of Nature.

The International Whaling Commission (IWC), estimated the Western gray whale population at 121 to 130 in 2007, the last year for which figures are available. The IUCN classifies them as "critically endangered".

During their feeding season, the gray whales must consume enough to maintain themselves for the rest of the year, including travelling long distances to their breeding grounds.

The feeding area near the proposed platform site, where Sakhalin Energy Investment Company already has two oil platforms, are also key because it is shallow, making it one of the few places where mother whales can teach calves to feed on the sea bed, WWF said. – Reuters