Blasts from undersea airguns fired by boats searching for oil could harm whales and should be studied further, said a report unanimously endorsed Monday by the International Whaling Commission.

Repeated bursts of air cause high levels of underwater sound that could affect whales' migration and mating patterns, the report said. It also noted that there might be a connection between the sound waves and humpback whale strandings.

The IWC recommended that governments and international groups study the issue and explore ways to mitigate noise pollution in the world's oceans.

"This has significant implications for reforming the way the oil and gas industry explore in our world's oceans," said Joel Reynolds, a lawyer with the nonprofit Natural Resources Defense Council. "Impacts on marine mammals can no longer be ignored."

Bruce Tackett, a spokesman for ExxonMobil Biomedical Sciences, said his company wasn't aware of harm done to marine life due to their energy surveys and has initiated research on the issue.

The IWC's unanimous support of the report was one point of consensus among the 70-nation body, which is bitterly divided over allowing commercial whaling.

A slim majority of nations on the IWC voted Sunday in support of a resumption of commercial whaling, but pro-whaling nations still lack the numbers needed to overturn a 20-year-old ban.

Japan on Monday held its first "normalization" meeting — a term used by Joji Morishita, chief spokesman for the Japanese delegation, to describe the process of turning the IWC away from being a conservation organization into more of a whale management group. No specific issues were discussed.

Both Japan and Iceland kill whales for scientific research — which critics call a sham — and sell the carcasses. Norway ignores the moratorium and openly conducts commercial whaling.