The 57-member body adopted a resolution which "strongly recommends" that subsidiaries of oil giants Exxon, Royal Dutch Shell and BP halt seismic exploration activity to avoid disturbing the whales.

Frenetic exploration activity is taking place in the gray whales' feeding ground in the Sea of Okhotsk, north of Russia's Sakhalin Island.

The resolution, adopted by consensus at the IWC's annual meeting in Sorrento, Italy, is based on a detailed report by its scientific committee.

The report warned that a potential "catastrophic oil spill" could wipe out the world's last remaining examples of the species.

Seismic activity should shop "in situations when displacement of whales could have significant demographic consequences," the scientists recommended.

The gray whale is one of the largest ocean mammals, measuring up to 15 metres (50 feet) in length and weighing 30 tonnes.

"It is a matter of absolute urgency that measures be taken to protect this population and its habitat off Sakhalin Island," said the resolution, which noted that only 23 reproductive females survive in the herd.

It also strongly recommended that nearby states develop or expand national monitoring and research programmes on western gray whales.

"The Sakhalin oil development clearly poses a serious threat to its future survival," warned the scientists in their report. "Exxon and Shell have both postponed construction plans until summer 2005, but BP will drill a well this summer."

The World Wildlife Fund (WWF) called on Royal Dutch Shell to suspend its plans to build an offshore drilling platform and install a seabed pipeline near Sakhalin, pending a full independent review.

The company has said it will not reconsider the project's design, and has offered to spend five million dollars on monitoring and research.

"This is a wake up call for Shell to pay proper attention to the environment when planning major oil projects," said Susan Lieberman, director of WWF's Global Species Programme.

"The potential for a catastrophic spill from Shell's oil project poses an unacceptable risk to this highly endangered whale population."

According to the IWC scientists, the project runs right through the single known coastal feeding habitat -- a strip of sea some 60 kilometres long and five kilometres wide (37 by three miles) -- used by females and calves.

The feeding ground "faces an obvious and immediate threat from industrial activities including noise, vessel traffic and the potential for a catastrophic oil spill."

The IWC's scientific committee has been reviewing research on the western gray whale since 1995.

The species was listed as "critically endangered" in 2000 by the International Union for the Conservation of Nature.

TERRA.WIRE