Making Sense of Ocean Noise

Source: Woods Hole Currents

WHOI Senior Scientist Peter Tyack of the Biology Department recently testified before the Subcommittee on Fisheries, Conservation, Wildlife, and Oceans of the Resources Committee of the U.S. House of Representatives. Discussing a bill to reauthorize the Marine Mammal Protection Act (MMPA), Tyack made the following comments:

"I have been fascinated since I was a child with the social behavior of marine mammals and how they use sound to communicate and explore their environment. As I started my career in basic research, it never occurred to me that chasing my personal interests would ever become central to such an important policy issue...

The dominant source of manmade noise in the ocean is the propulsion sounds from ships, which account for more than 90 percent of the acoustic energy humans put into the sea...Studies have demonstrated that marine mammals respond to ships, dredging, icebreaking, construction, and sound sources such as pingers, air guns, and sonars. Most of these sound sources are currently unregulated simply because the National Marine Fisheries Service (NMFS) chooses not to enforce the prohibition against taking marine mammals by ‘harassment.’

Ships regularly collide with marine mammals and often kill them. So many highly endangered right whales are killed by vessel collision that population models predict this additional mortality may drive the species to extinction. Yet there is no regulation of this risk.

Many users of sound in the sea—from the Navy to geophysical contractors to academic oceanographers—find themselves in a no-man’s land, where the appropriate regulatory process for incidental harassment takes is obscure...We cannot protect marine life from intense underwater noises until we get better at detecting when a marine mammal or sea turtle is in the danger zone...

It is ironic that NMFS has grown an elaborate process for permitting negligible harassment by researchers, while ignoring widespread and predictable lethal takes caused by activities that do not benefit marine mammals... I am very concerned that the current permitting process will hold scientific research that enhances the survival or recovery of species or stocks to a stricter standard than activities that harm marine mammals."