The ocean is loud: Ship propellers, sonar, oil and gas drilling and other industrial work make sounds, even if, like the proverbial tree falling in the forest, no one can hear it.
But marine animals can, and all that noise has been shown to interfere with their behavior, since many of them, from whales to invertebrates, use sound for all kinds of activities, including to communicate, to find food or each other, to avoid predators and to migrate.
And while the ocean was never a quiet place — full of natural rumblings, clickings and chatterings — the problem has grown worse over the last 100 years or so, and significantly increased over the last 50 years in some places, much of it from commercial shipping, according to the National Oceanic and Atmospheric Administration.
So the agency, which manages and protects marine life in United States waters, released on Wednesday a draft for a strategy to reduce the effects of ocean noise, and invited public comment.
The Ocean Noise Strategy Roadmap draft is an early step in a 10-year plan to quiet the oceans and reduce some of the harmful effects on aquatic species. The public comment period will end July 1, and a more concrete plan will be put in place in the coming months.
At this point, the oceanic administration’s road map includes more research on the cumulative effects of noise on ocean animals, and outreach to other governmental, military, environmental and industry groups. The administration, the Navy and the Bureau of Ocean Energy Management have commissioned theNational Academy of Sciences to conduct a review of the cumulative effects of sound on marine mammals, and the administration has already started to reduce its own impact by using quieter research vessels.
While the agency has been collecting information on ocean noise and its effects on certain species for several years, the full range on marine animals is not completely understood, though the symptoms are often striking.
Sea mammals, in particular, have evolved to take advantage of how well and far sound can travel under water, and to compensate for poor visibility in the dark deep. Whales and dolphins have extraordinary hearing and the ability to communicate in widely varying voices.
But sound produced by human activity can get in the way. In the waters off Massachusetts, oceanic scientists have observed that many whales no longer seem to register the sounds of ships, said Richard Merrick, the chief scientist for the oceanic administration’s fisheries service. They do not necessarily associate the sounds of ships with danger, he said, so they do not always move out of the way.
Elsewhere, other species of whales, he said, “just shut up” when ships pass by, in part because many species communicate using sounds in the same range of frequency as the noise produced by ship engines.
And some studies have demonstrated that cod and haddock populations in the Atlantic, both of which are considered or are becoming overfished, can hear and also avoid low-frequency sounds, though it is not clear what the effects might be on their behavior, said Jason Gedamke, an acoustics expert with the oceanic administration and a lead author of the road map. Cod, in particular, also make lots of noise when they spawn, but the implications of human sound on that behavior is not fully known, either, Dr. Gedamke said.
Michael Jasny, the director of the marine mammal protection project for theNatural Resources Defense Council, said the plan marked a big change in how the oceanic administration sees ocean noise: as a problem that needs to be addressed more broadly instead of case by case.
Mr. Jasny added that he was disappointed that the announcement lacked a concrete plan or a schedule for being carried out.
But unlike other ocean pollutants, this problem can be solved, he said: “Once you stop making noise, it goes away.”