Projected LFAS Sound Levels in the Gulf of Maine

Projected LFAS Sound Levels in the Gulf of Maine Download PDF file

This figure was developed to illustrate to the average person the potential impact of the Navy's Low Frequency Active Sonar (LFAS) system. The Gulf of Maine was chosen for this analysis because 1) it is home to the Northern Right Whale, an endangered species under the "protection" of the National Marine Fisheries Service (NMFS), 2) it includes the Georges Bank and surrounding waters, the breadbasket of the Atlantic fishing industry, 3) it includes Stellwagen Bank, a National Marine Sanctuary, and 4) it has waters exceeding 200 meters in depth, where the Navy will operate its LFAS-equipped ships. Sound contours were drawn for several possible 'criterion' or 'threshold' sound levels, of which only the highest and most dangerous (180 dB) is used by the Navy and NMFS.

125 - 120 to 125 dB has been associated with disrupted whale behavior, including scattering, silence, and stranded calves (an exceedingly rare event in nature), as well as diver impairment (Hawaii 1998).

145 - 145 dB is the limit set by the Navy Bureau of Medicine and Surgery (BUMED) to protect military divers from panic and physical injury.

160 - 155 to 160 dB has been associated with mass marine mammal strandings and deaths (Bahama 2000).

180 - 180 dB is the criterion currently approved by the National Marine Fisheries Service, the agency in the United States charged with the mission and authority to protect endangered marine species through the Marine Mammal Protection Act. 180 dB, a level 100 times more intense than that associated with mass whale strandings and deaths, was proposed by the US Navy itself in 1999.

Robert W. Rand, INCE.
October 2, 2002.