Two federal agencies on Friday announced a major review of how seismic testing for oil and gas deposits affects marine mammals and fish in deep waters off the Gulf of Mexico.
So-called seismic surveys entail blasts from air guns or other ship-borne devices that send out powerful sound waves that reflect the shape and extent of oil and gas fields under the ocean floor. Industry officials say the practice is necessary for efficient, safe exploration in deep seas.
The testing has long been controversial. Environmental groups have taken companies connected to the tests to court many times, contending that the blasts cause hearing loss in whales and other protected species.
In addition, scientists have observed avoidance behaviors among marine mammals and fish during testing, which can take place over weeks.
Seismic testing has also caused disturbances to animals' feeding and breeding, according to some scientists.