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Date: Feb. 10, 2003
Contacts: Vanee Vines, Media Relations Officer
Andrea Durham, Media Relations Assistant
Office of News and Public Information
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Publication Announcement

Impact of Noise on Marine Mammals Remains Unclear

The ocean environment has always included an abundance of natural noises, such as the sounds generated by rain, waves, earthquakes, and sea creatures. However, a growing number of ships and oil rigs, as well as increased use of sonar by navies and researchers, is adding to the natural noise that already surrounds marine life. Although noise in the sea has increased steadily since the Industrial Revolution, there is little information on exactly how noisy it has become or how marine mammals in particular react to the noise. Nevertheless, recent episodes in which dolphins and whales have beached themselves while human-generated sounds were being deployed nearby have raised questions about the impact of ocean noise.

A new report from the National Academies' National Research Council says that a single federal agency should be put in charge of monitoring marine noise and should fund research into how human-generated sounds may affect marine mammals and other sea life. This agency's priorities should include investigating possible links between the use of high-energy, midrange sonars and mass strandings of marine mammals, and studying whether human-generated sound induces stress or subtle behavioral changes in these animals.

Beaked whales in particular have suffered traumatic injuries and stranded themselves in locations where naval sonar was being used nearby, but there is not enough data to determine whether sonar caused the strandings, said the committee that wrote the report. It is important to determine whether there is any connection between sonar use and beachings and, if so, whether this link is peculiar to beaked whales or if other sea species may be affected as well. Progress in this area can only be made if researchers study the impact of noise in an actual ocean environment, the committee noted.

Scientists' efforts to determine how sound affects marine life are hindered by a lack of general information about both the amount and sources of ocean noise. A count of commercial ships coupled with observational data suggests that noise levels from ship traffic have increased approximately 15 decibels in the last 50 years, the report says; it is difficult to know whether sound levels are continuing to increase, however, because newer ships may be quieter. The little information that does exist is scattered among shipping companies, oil and gas businesses, academic institutions, and the military. To remedy this, the agency mandated to facilitate ocean-noise research should gather all existing data on human-generated ocean noise into one comprehensive database, the committee said. The agency should also initiate a long-term program to monitor sound in the sea, targeting important marine-mammal habitats such as coastal areas and known migration paths, feeding grounds, and breeding areas.

Also needed are better models to predict the noise levels that will be generated in the ocean by particular human activities. For example, a better understanding of what noise ships generate would give researchers the ability to project how much noise will occur in different parts of the ocean based on ship traffic patterns. Such projections would be particularly useful for understanding ocean noise in areas of the globe where direct monitoring with instruments is difficult or impossible.

In addition, acoustics experts, marine biologists, oceanographers, and other users of sound in the ocean, such as the military and the oil industry, should make greater efforts to raise public awareness of the complex scientific and technical issues involved in trying to understand the potential impact of noise on marine mammals and the need for additional research, the committee said.

The study was requested by the National Ocean Partnership Program, a federal interagency project, and sponsored by the Office of Naval Research, the National Oceanic and Atmospheric Administration, the National Science Foundation, and the U.S. Geological Survey. The National Research Council is the principal operating arm of the National Academy of Sciences and the National Academy of Engineering. It is a private, nonprofit institution that provides independent advice on science and technology issues under congressional charter. A committee roster follows.

Read the full text of Ocean Noise and Marine Mammals for free on the Web, as well as 2,500 other publications from the National Academies. Printed copies will be available for purchase from the National Academies Press this spring; tel. (202) 334-3313 or 1-800-624-6242 or on the Internet at Reporters may obtain a pre-publication copy from the Office of News and Public Information (contacts listed above).

Division on Earth and Life Studies
Ocean Studies Board

Committee on Potential Impacts of Ambient Noise in the Ocean on Marine Mammals

George Frisk (chair)
Senior Scientist
Ocean Acoustics Laboratory
Department of Applied Ocean Physics and Engineering
Woods Hole Oceanographic Institution
Woods Hole, Mass.

David Bradley
Senior Research Scientist
Applied Research Laboratory
Pennsylvania State University
State College

Jack Caldwell
Manager for Seismic Research Services

Gerald D'Spain
Associate Project Scientist
Marine Physical Laboratory
Scripps Institution of Oceanography
San Diego

Jonathan Gordon
Honorary Lecturer
Gatty Marine Laboratory
University of St. Andrews
St. Andrews, Fife

Mardi Hastings+
Associate Professor
Biomedical Engineering Center
Ohio State University

Darlene Ketten
Assistant Professor
Department of Otolaryngology
School of Medicine
Harvard University, and
Senior Scientist
Biology Department
Woods Hole Oceanographic Institution
Woods Hole, Mass.

James Miller
Department of Ocean Engineering
University of Rhode Island

Daniel L. Nelson
Senior Program Manager
Physical Sciences Business Unit
BBN Technologies
Cambridge, Mass.

Arthur N. Popper
Department of Biology, and
Neuroscience and Cognitive Science Program
University of Maryland
College Park

Douglas Wartzok
Vice Provost for Academic Affairs, and
University Graduate School
Florida International University


Jennifer Merrill
Study Director

+ resigned from committee November 2002