LOS ANGELES -- Noise from supertankers, oil exploration and new military sonar equipment scrambles the communications systems of sea life, forcing changes in migration routes and breeding grounds, a new report warns.
"We're playing Russian roulette with our oceans, and we can't afford to do that," said Joel Reynolds, senior attorney with the Natural Resources Defense Council, the environmental group responsible for the report.
The study, scheduled to be released Monday, says underwater noise pollution could alter the ocean habitat and calls for a harder look at how noise affects sea creatures as well as stiffer regulations to protect them.
"It is a serious problem. The problem is, we don't know how serious it is," said Roger Gentry, acoustics team coordinator for the National Marine Fisheries Service, which oversees most marine life in U.S. waters.
The report was "a pretty fair summary" of the issues that acoustics experts in government, the military, academia and the environmental movement have struggled with as they assess how noise affects sea life, Gentry said.
Ocean noise is similar to the visual effects of strip malls and electrical wires on dry land, according to Cornell University bioacoustics expert Christopher W. Clark.
Though Clark's studies have suggested that the effects of two high-profile ocean-noise emitters could be less dire than environmentalists feared, he also urges caution.
"If you just went out and listened in the Channel Islands, you'd be appalled," he said. "Those places off San Francisco, off Los Angeles -- you're just in the middle of an acoustics traffic jam."
Those three sites, as well as Monterey and San Diego bays, are pinpointed in the study as having high levels of underwater noise and abundant sea life. Environmentalists are calling for special efforts to reduce noise in those locations.
In dark sea waters, mammals such as whales and dolphins appear to use their hearing -- much as humans use sight -- to seek out food, find mates, guard their young and avoid predators.
Man-made noise may harm marine mammals, especially since sound travels faster through water than air. Whales sometimes change direction during migration to avoid noise and abandon their traditional breeding grounds, scientists say.
However, research is too new to say definitively whether these behavioral changes may harm mammal populations in the long term, said Clark and Gentry.