YUZHNO-SAKHALINSK, Russia, Jan. 17 (UPI) -- Building an oil rig in the northwest Pacific near a feeding habitat of the gray whale could endanger the critically threatened species, conservationists say.

Sakhalin Energy Investment Co., partly owned by Shell, says it will build a third platform to join two existing platforms off Sakhalin Island in the Russian Far East, a World Wildlife Fund release reported Monday.


This is a primary feeding area for the western population of the gray whales, said to number no more than about 130 whales, the environmental group said.

The construction and operation of another offshore platform could potentially disrupt feeding behaviors and increase the chance of fatal ship strikes, a spokesman for the group said.

"Just around 30 female western gray whales of breeding age remain -- the population is already on the brink of disappearing forever," Aleksey Knizhnikov, oil and gas environmental policy officer for WWF-Russia, said. "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 critically endangered and separate from the eastern population, which numbers about 20,000 to 22,000. Genetic studies indicate the two populations probably do not mix.