Deafness in the deep

A new threat to whales, dolphins and other marine life exists in the worlds oceans, as the US Navys new sonar technology could have huge long-term effects on their whole way of life. Leigh Calvez reveals why the lords of the sea aren't singing any more.

Ever eager to protect itself against enemies, the US Navy has developed a new technology to help it detect opposition submarines. It's called Low Frequency Active (LFA) Sonar, and is capable of sending low frequency sound pulses - up to 240 decibels - into the water over hundreds of miles, bouncing an echo back to the listener, thus detecting an enemy submarine.

In the depths of the oceans, man-made sonar is nothing new, but this is the first time that it has been as loud and as powerful. Surely, then, it has been tested for its effects on the creatures of the sea that depend upon sound in the way that we depend on sight: the whales and dolphins?

Not sufficiently, say many scientists. Studies published in scientific literature over the past twenty years suggest that sounds from 110 to 120 decibels begin to cause disturbance to whales. Dr. Linda Weilgart, a Canadian biologist from Dalhousie University who has studied sperm whale communication for sixteen years, points to the long-term effects from the use of this technology as reason for concern. In The Christian Science Monitor, she states, 'to determine the health of a population (that is, whether it will survive), we need detailed, accurate population size figures, birth rates, death rates, and growth rates. We have none of these statistics for almost any whale or dolphin likely to be affected by LFAS.'

After using the technology for years without completing an Environmental Impact Statement (EIS), thus violating of the National Environmental Policy Act (NEPA), the Navy agreed to test the sonar system in order to complete an EIS. It hired a team of US scientists to design a study testing the effects of LFA on only four species of whales. Blue and fin whale feeding behaviour and gray whale migration patterns were tested off the coast of California in September 1997 and January 1998, respectively. Humpback whale behaviour was tested off the Big Island of Hawaii in March 1998, during the breeding and calving season. These experiments only tested immediately observable changes in behaviour to an exposure level of around 150 decibels, a sound well below the 240 decibel level at which the technology will be deployed. Long-term effects are extremely difficult to test in the natural system of the ocean and were ignored by the scientists.

During the tests off California, scientists recorded a decrease in the number of blue and fin whale calls. The results of the gray whale tests posted on the Navy's SURTASS (Surveillance Towed Array Sensor System) LFA Sonar website state, 'Source in migration path: increased avoidance with increased source level.' This significant result was reported as: 'No biologically significant response', a questionable assertion in scientific research since this is impossible to know until long-term impacts can be assessed.

In Hawaii, half of the humpback whales tested temporarily stopped singing – the behaviour for which this species is famous. Additional aberrant behaviours from other whales and dolphins in the area were also reported. Twelve days after the tests began, a three-month old humpback whale calf was sighted without its mother for at least five hours and displayed unusual behaviour. Nine days later a two-to-three-month old spinner dolphin calf was seen without its mother or pod, while a single melon-headed whale calf was found alone, dehydrated and without its pod nine days after the testing ceased. Interference with the crucial mother-calf bond has been cited as reason for concern over the use of LFAs.

NATO has also tested a similar type of sonar with serious effects on a little known species of deep diving beaked whale. On 12 and 13 May 1996, twelve Cuvier's beaked whales were stranded and died along the Kyparissiakos Gulf coast of Greece. Alexandros Frantzis, a Greek scientist, who reported the findings in Nature, concluded NATO's LFA Sonar caused the deaths. In his posting of this article on MARMAM, an electronic bulletin board for the Marine Mammal Society, he added, 'I close this message hoping that the following article could be a "useful tool" in the hands of specialists who are discussing with the US Navy, in order to convince them to stop their dangerous games'.

Most opposition to LFA has come from scientists outside the US. Dr. Hal Whitehead, from Dalhousie University, who studies sperm whales, explained this conflict of interest in his article, Deaf Whale Dead Whale. Almost all experienced marine mammal scientists in the US working on acoustics have links to the U.S. Navy. This means that there are very few competent scientists who feel free to criticize U.S. Navy projects.

The draft EIS was submitted on 29 August 1999 for a 90-day public comment period. Seven days before the end of the period, the Navy made public its intention to deploy the sonar by applying for an incidental take permit from the National Marine Fisheries Service (NMFS). This action acknowledged the potential for harm, disturbance or death in 43 species of marine mammal including endangered humpback and blue whales and critically endangered northern right whales and Hawaiian and Mediterranean monk seals. The effects of loud, low frequency sound are virtually unknown for endangered sea turtles, diving sea birds, fish, plankton and even basic ocean life processes.

Thus far the Navy has spent $350m on the project and defends the use of this new technology on the website under the heading Why America Needs LFA Sonar, by explaining the need to protect billions of dollars of raw materials and manufactured goods destined for nations around the world. The military used to defend citizens; now it's defending commerce.

We depend on the oceans for life. Until we have a clear understanding of the long-term impacts of this technology not only on whales but all ocean life, its use should be prohibited and alternative methods to protect our commerce should be found.

Leigh Calvez is a marine researcher for the US-based Quiet Sea Coalition

This article first appeared in the Ecologist June 2000