April 4, 2002
Dear Dr. Hogarth:
These comments on the U.S. Navy's proposed Low Frequency Active (LFA) sonar system summarize new scientific information. They are submitted on behalf of the Biodiversity Legal Foundation and myself. These comments supplement our joint petition to you dated August 31, 2001, requesting that the Atlantic white marlin be listed as a "threatened" or as an "endangered species" throughout its range and that its critical habitat be designated and protected under the authorities provided by the Endangered Species Act (ESA) and other statutes. We also request that the new information in this letter be considered formally as part of ongoing National Marine Fisheries Service (NMFS) reviews conducted under authority of the Marine Mammal Protection Act (MMPA) and National Environmental Policy Act (NEPA).
Based on this new information, we are very concerned about the severity of the effects of use of high intensity sonar on white marlin and other marine life over very large areas of ocean. As discussed below, LFA sonar is capable of producing a "kill-zone" larger than the state of Texas.
We understand that NMFS is in the final stages of considering whether the U.S. Navy's proposed LFA sonar system should be issued a permit and a letter of authorization for deployment under authorities provided by the MMPA and the ESA. However, in addition to its impacts on marine mammals and endangered species, we believe that NMFS has a responsibility to consider the full extent of the "collateral damage" that will occur with deployment of LFA sonar, and that NMFS must consider the cumulative effects on all forms of marine life that will be adversely affected over areas totaling thousands of square miles. As discussed below, it is important to understand that alternatives to LFA sonar exist which are much less destructive to marine life.
As you know, LFA sonar is designed to detect and track quiet submarines. According to its Final Environmental Impact Statement (FEIS), the Navy is planning to deploy it in 80% of the world’s oceans (omitting only the waters of the Arctic and Antarctic). Scientists and organizations have expressed concern about the potential adverse impact of LFA sonar (including tissue rupture and death) on marine mammals, fish and other marine life because its high intensity sound is transmitted over very long distances. We are particularly concerned about its direct and indirect lethal effects on the imperiled large pelagics - white marlin, blue marlin, bluefin tuna, bigeye tuna, swordfish, sailfish, spearfish and many species of large sharks of the Atlantic - and other marine resources, including their prey, all of which will be at risk.
According to new scientific information now available, at its expected power level of 240 decibels (dB), LFA sonar could produce a "kill zone" for not only marine mammals and endangered species but also fishery resources in an area hundreds of kilometers (km) in diameter. This high intensity sonar is described as the loudest sound made by man (presumably not including bombs) and is equivalent in intensity to the noise created by a Saturn rocket at liftoff. Actually, the Navy has indicated it has the capability to produce an even higher decibel level sonar, but that particular level is "classified." So, we know it will be actually even worse for marine life than 240 dB.
As you may know, the Navy tested LFA sonar at least 22 times secretly, in violation of several federal laws including NEPA, MMPA, ESA and the Coastal Zone Management Act (CZMA), before the Natural Resources Defense Council discovered the activity in 1995. Under pressure, the Navy then agreed to write an EIS. It hired scientists, Christopher Clark (Cornell U.) and Peter Tyack (Woods Hole Oceanographic Institute) to test the effects of the sonar on four species of whales (blue, fin, gray and humpback) for one month each. The LFA sonar test levels were never above 155 dB and thus were always much lower than the actual sonar which is about 240 dB. The scientists conducting these lower intensity level tests said: "It will be difficult to extrapolate from these tests to predict responses at higher exposure levels." On the basis of this limited, lower decibel level testing, the Navy concludes in its FEIS that it is safe to expose marine mammals to LFA sonar at sound pressure levels of 180 dB, even though the scientific research program never exposed them to levels above 155 dB. In its FEIS (Appendix D) the Navy admits, "the lack of empirical data in the received level range of 155-180 dB is an issue." That is an understatement!
It is important to realize that the decibel scale is not linear, but logarithmic. This means that 160 dB is 10 times the intensity of 150 dB, 170 dB is 100 times the intensity of 150 dB and so on. Therefore, the full deployment intensity of LFA sonar is 1,000,000,000 (one billion) times the intensity of 150 dB - the intensity at which lethal effects are documented, as noted below.
In March of 2000, more than a dozen beaked whales, two minke whales and at least one dolphin stranded in the Bahamas following mid-frequency range sonar exercises conducted by the Navy. (The rest of the resident population of beaked whales, which had been studied intensively by a research scientist who had photographed and named each one, has not been seen since.) After denying responsibility for more than a year, the Navy/NOAA report (December 2001) on this stranding http://www.nmfs.noaa.gov/prot_res/overview/new.html) admitted that the animals that died had been exposed to sound pressure levels below 180 dB, which is the level that the Navy had said (in its FEIS) is safe. Obviously, the FEIS is flawed in this fundamental aspect. Mid-range sonar intensity levels about 155 dB (presumably the highest LFA sonar level tested in the Navy's scientific research program) and thus well below 180 decibels, were in fact lethal to marine mammals. Moreover, the animals affected were located as much as 20 km from the source of the sonar; thus in this case the "kill zone" for this mid-range sonar was at least 40 km in diameter.
LFA sonar does not attenuate as rapidly as does mid-range sonar of the same intensity. Since LFA sonar maintains much more of its initial intensity over much greater distances, it affects a much broader area than does the mid-range (or "tactical") sonar employed by the Navy in the Bahamas. This is precisely why LFA sonar is being developed. To illustrate, LFA sonar used during previous NATO exercises in the Mediterranean off Greece resulted in marine mammal strandings and mortality at exposure distances of 100 km and estimated exposure intensity levels of 150 to 160 dB, according to the calculation made from the SACLANTCEN Bioacoustics Panel report on this stranding. The direct "kill zone" of LFA sonar can thus be 200 km in diameter vs. the 40 km "kill-zone" of mid-range sonar.
Contrary to claim in the Navy's FEIS, that exposure levels below 180 dB are safe, there is no empirical evidence showing that LFA sonar has no deleterious effect on marine animals between 155 and 180 dB. The Greek and Bahamian mammal strandings demonstrate that marine animals are not safe even if they are located at distances of 20 to 100 km from the source and exposed to sound pressure levels well below 180 dB. As noted above, scientists have estimated that the whales involved in these two mass strandings (Greece in 1996 and the Bahamas in 2000) were exposed to sonar levels of between 150 and 160 dB.
Sound behaves differently in water compared to air. It travels five times faster in water than in air. In water, it is also transmitted much farther with much less attenuation than in air. (And LFA sonar maintains its intensity much farther than does mid-range sonar.) LFA sonar will maintain relatively high intensity levels hundreds of miles from the source. For example, a marine mammal scientist working off the Washington coast recorded a loud sound (measured at 140 dB). After investigating, he learned it was produced by Navy LFA sonar exercises conducted off Southern California - a distance of over 900 miles!
Sound penetrates an animal's body when immersed in water. In air, 99.97% of the acoustic energy is reflected from a body. In water, however, there is no reflection or reduction of energy because the body is mostly water. Essentially all of acoustic energy goes into a body immersed in water. This effect, which can cause tissue rupture and hemorrhage, has not been adequately addressed in the Navy's FEIS. The implications (of the effect of sound penetration) for marine life are very serious, as described next.
The possible mechanisms causing lethal injuries to mammals as well as other marine animals such as fish include gas bubble activation and resonance. Each will be discussed below. As noted above, such lethal effects can be produced at exposure levels of 150 to 160 dB and thus well below the level the Navy says is safe (180 dB). The Navy's plan is to deploy LFA sonar at an effective source level of as much as 240 dB (the actual source level is classified). This means it could be 180 dB up to 1 km away from the transmitting vessel but still 160 dB at a distance of several hundred miles from the source. While the Navy’s FEIS focuses on the possible auditory effects of LFA sonar, intense sound pressure waves also have harmful non-auditory physiological effects, which are not addressed in the FEIS. Evidence of two such effects has been presented recently, as follows.
The first lethal mechanism, discussed by three Navy scientists (Houser, Howard and Ridgway) in The Journal of Theoretical Biology (November 2001), involves moderate level sound waves (as low as 150 dB, which was the lowest level they modeled) activating the growth of microscopic bubbles in the supersaturated blood and tissue of cetaceans. These bubbles then grow and can cause embolisms, hemorrhaging and localized pressure on the nervous system. Significant oxygen deprivation by blood vessel blockage can kill brain cells and produce stroke. For supersaturated gasses dissolved in cells rather than the blood, activation of bubble formation can rupture the cell walls.
The Navy has argued that the Bahamas stranding is not relevant to concerns about LFA sonar because it was using mid-frequency sonar in the Bahamas, not LFA sonar. However, bubble growth is essentially independent of the frequency of the sound wave and LFA sonar would, in fact, affect more animals since low frequency sound travels farther.
Gas supersaturation will be greatest in those species that dive to great depths in search of prey. Obvious examples include the imperiled bluefin tuna, swordfish, blue marlin, bigeye tuna and deep-diving whales. Using the new pop-off satellite tagging technology, bluefin tuna have been shown to reach depths below 2,400 feet (the limit of the pressure-sensing device first employed) and to stay beyond such depths for more than an hour (on a daily basis) (Block, et al., 2001, Science 293:1310-14). Deep-diving species will accumulate the highest concentrations of gasses dissolved in their blood and tissues and thus will be especially vulnerable to supersaturated gas bubble activation by high intensity sonar. The Navy's FEIS does not address the potential for injury from sound-activated bubble growth in fishery resources or marine mammals.
The second mechanism for lethal injury involves hemorrhaging caused by acoustic resonance of the LFA sonar signal in cranial and other airspaces such as lungs and swim bladders. Specifically, the rapid change in pressure (from very high to very low several times per second for the duration of the one-minute LFA sonar blast) can rupture the delicate membranes enclosing the airspace.
In their chapter "Underwater Noise Pollution and its Significance for Whales and Dolphins" (in Simmonds and Hutchinson, 1996, The Conservation of Whales and Dolphins. John Wiley & Sons.), Jonathan Gordon and Anna Moscrop state that shock waves caused by intense underwater sound sources can cause direct tissue damage. Animals with air filled lungs and swim bladders are especially vulnerable because of the large difference in impedance between air in the lungs or swim bladders and their body tissues or seawater. Submerged animals exposed to explosions at short range showed hemorrhage in the lungs and ulceration of the gastro-intestinal tract.
Kenneth Balcomb, director of the Friday Harbor Orca Research Laboratory and the marine mammal scientist who discovered the Bahamas stranding, suggested in a letter to Joseph Johnson, the LFA sonar OEIS/EIS program manager (February, 2001) that those beaked whales stranded from non-auditory physiological impacts caused by acoustic resonance of the sonar signal in their cranial airspaces (at exposure intensity levels estimated to be 150 to 160 dB). This resulted in the hemorrhages observed during necropsies. (The frequencies of LFA and mid-range sonars match the cranial airspace resonance frequencies of beaked whales at normal foraging depths.) He has stated: "I have had the unique opportunity to witness and study a mass stranding of whales and a dolphin caused by a U.S. Naval Sonar Exercise in the Bahamas (Pirie, ltr. June 15, 2000). That incident unequivocally demonstrated the lethality of high-powered sonars, and it provided the opportunity to understand how sonar has been inadvertently killing whales in vast expanses of ocean around the world.
The killing is largely due to resonance phenomena in the whales' cranial airspaces that are tearing apart delicate tissues around the brains and ears. This is an entirely separate issue from auditory thresholds and traumas that the Navy has fixated upon. In my earlier comments, I questioned whether there might be a problem with injurious resonance phenomena created by the sonar system described in your OEIS/EIS; but, now I have seen the problem and can attest to the fact that there is massive injury to whales caused by sonar. This is not an exaggerated statement, and I am reasonably sure that the Navy knows that.
At least seven beaked whales died in the Bahamas stranding that I witnessed; and, I had opportunity to examine four of the carcasses by necropsy. All of these whales that were examined evidenced similar lesions, i.e. hemorrhage in the acoustic regions of the cranium and mandible and in tissues adjacent to airspaces around the earbones (NMFS ltr. June 14, 2000). One fresh specimen that was examined by ultra high resolution computerized tomography (UHR-CT) evidenced a subarachnoid hemorrhage (brain hemorrhage) with a direct path to the ear hemorrhage. This same specimen evidenced lung hemorrhage and laryngeal hemorrhage upon dissection. These hemorrhages are of the type of damage reported in laboratory animals exposed to LFA at lung resonance frequency, and they strongly corroborate the theoretical explanation of such injuries in these whales."
This evidence was recently presented, analyzed and affirmed by a number of experts in the fields of marine mammalogy and bioacoustics. Although resonance effects are acknowledged by the Navy as a potential problem for humans, it is not discussed in the FEIS with regard to any marine species.
Therefore, through these two potentially lethal mechanisms, not only marine mammals but also most fish species and many other forms of marine life are vulnerable to the direct lethal effects of sonar at intensity levels of 150 to 160 dB - well below (100 to 1,000 times less than) that which the Navy has claimed is safe (i.e., 180 dB). Because LFA sonar travels very long distances with little attenuation, the area so affected will be quite large - more than 200 km in diameter. In fact, the Navy states in its FEIS that LFA sonar can still be 160 dB several hundred miles from the source. Therefore, the potential direct "kill-zone" for LFA sonar is an area larger than the state of Texas.
In addition, sublethal effects produced at intensity levels well below 180 dB are also of concern, particularly for many species of fish. As you are well aware, a large number of fish species have evolved elegant, highly sensitive auditory and lateral line systems that detect bodies moving throughout their environment. Some such as many species of sharks have pressure-sensing systems covering much of their bodies. Such a sensory apparatus allows schooling species to move in unison. Predatory species such as sharks, tunas, marlin, swordfish and sailfish depend on this system and especially their auditory systems to locate potential prey well beyond the limits of their vision. These systems are also essential in warning the large pelagics and other species of approaching predators. Thus, these are extremely important sensory mechanism for many marine fishes, which could easily be damaged by sonar levels lower than those causing direct mortality, as described above. Exposure to such sonar levels might not kill them by trauma, but could certainly render them incapable of locating their prey or detecting onrushing predators. Even temporary loss of function could be fatal. Damage to fishes' auditory and lateral line systems could thus become a significant cause of additional indirect mortality in a much larger area that extends well beyond the direct "kill zone" caused by trauma resulting from gas bubble activation and resonance effects, which is at least 200 km in diameter.
The extent of sublethal effects of LFA sonar on marine fishes' lateral line systems has not been evaluated in the Navy's FEIS. The only study of fishes' auditory system impairment cited in the FEIS (Hastings, et al., 1996, J. Acoust. Soc. Am. 99(3):1759-66) is one, sponsored by the Navy, which focused on the oscar (Astronotus ocellatus), a freshwater species. However, of all fishes studied, the oscar is known to be among the most insensitive ("deaf") to sound (Arthur Myrberg, March 29, 2002, personal communication). It would be very useful to know the effects of high intensity sonar on a sensitive fish species such as the highly sensitive goldfish or members of the catfish or drum families.
We became concerned about the threat of high intensity active sonar when we learned it was to be tested in the Azores, off New Jersey and in the Bahamas, among other places (e.g., Canary Islands, off North Carolina, California and Hawaii). These areas are very important to white marlin and to the imperiled blue marlin, swordfish, bluefin tuna, bigeye tuna, mako sharks, spearfish and many other species.
As you know from our letter to you dated February 14, 2002, identifying "critical habitat" of Atlantic white marlin, the area between the Bahamas and Cuba may be the epicenter of spawning for the northern hemisphere's population of white marlin. The Bahamas are also an important year-round nursery area for this severely imperiled species. The Navy exercises were conducted in the Bahamas because its usual weapons testing area (Vieques Island) off Puerto Rico had become politically controversial. However, that area between Puerto Rico and the Virgin Islands, appears to be a prime spawning area for not only white marlin but also blue marlin and swordfish.
The Azores are among the adult white marlin's primary summer-fall feeding grounds. However, its most important summer-fall feeding grounds include the edge of the continental shelf from just below Cape Hatteras, NC, to the eastern tip of Georges Bank and similar areas of the northern Gulf of Mexico. We recently learned that the Navy intends to locate its national training program (for employing LFA sonar) just to the southwest of Cape Hatteras at Onslow Bay, North Carolina. Thus, areas where sonar is to be used are among this species' most "critical habitats."
In our listing petition we identified high intensity sonar as a continuing threat to the white marlin's existence. These critical habitat areas for white marlin, which have been either used by the Navy or identified for future use for active sonar exercises, are also prime spawning and feeding areas (thus are critical habitat) of Atlantic blue marlin, whose population is nearly as endangered as is that of white marlin, as well as the imperiled north Atlantic swordfish. The Azores are also a known prime fall feeding ground for the north Atlantic bluefin tuna whose population is equally imperiled as are the two Atlantic marlin species and bigeye tuna which are more imperiled than is the swordfish. Based on the new information summarized above, it appears that LFA sonar deployment as proposed (and even mid-range sonar use) in these critical habitat areas will kill many individuals of these species, whose populations (i.e., white marlin, blue marlin and bluefin tuna) are already on the brink of extinction, and adversely affect many other forms of marine life, including their prey, in adjacent areas. As noted above, the direct and indirect "kill zones" around such high intensity sonar blasts could, according to the Navy's FEIS, extend several hundreds of miles and thus affect many imperiled species in thousands of square miles of their critical habitats.
The Navy has stated in testimony before a Congressional subcommittee that it has passive listening systems that can detect quiet submarines in littoral waters where previously they were thought to be undetectable. Evidence concerning the present and future availability of new and advanced passive sonar technologies (such as Advanced Deployable Systems tested off California, Robust Passive Sonar (RPS) and towed arrays equipped with Acoustic Rapid Commercial-off-the-shelf Insertion (ARCI) processing) which have the potential to locate quiet submarines without harm to marine life are not discussed in the FEIS. (See RADM Malcolm I. Fages and RADM J.P. Davis, Statement before the House Armed Services Committee, Military Procurement Subcommittee (June 27, 2000) and Presentation of Dr. Thomas J. Green, Defense Advanced Research Projects Agency (DARPA), to Department of Defense (Sept. 6-8, 2000) noting the potential effectiveness of a "Robust Passive Sonar" system apparently in development at DARPA). Why authorize highly dangerous LFA sonar when safe alternatives exist?
According to the Marine Mammal Commission (1996) "if the LFA system is made available for world-wide employment as proposed, all species and populations of marine mammals could possibly be affected. The possible effects could include: death from lung hemorrhage or other tissue trauma; temporary or permanent hearing loss or impairment; disruption of feeding, breeding, nursing, acoustic communication and sensing, or other vital behavior…; annoyance and subsequent abandonment or avoidance of traditional feeding, breeding, or other biologically important habits…; psychological and physiological stress, making animals more vulnerable to disease, parasites and predation; and changes in the distribution, abundance, or productivity of important marine mammal prey species and subsequent decreases in both individual marine mammal survival and productivity and in population size and productivity."
In its recent report "Marine Mammals and Low Frequency Sound: Progress Since 1994" the National Research Council (NRC) expressed concern about the potential effects of low frequency sound on marine life including zooplankton, fish and other endangered species such as turtles. The NRC noted that there has been almost no attempt to study the effects on fish.
If the Navy is given approval by NMFS and it begins to deploy LFA sonar, it will doubtless be used in or will affect those areas where submarines are most likely to lurk - the approaches to and edges of the continental shelf and around biologically important islands and seamounts such as those of the Azores and the Caribbean. Unfortunately, as noted above, these particular areas are the prime habitats for all the large pelagic species of the Atlantic throughout their annual migrations, as described in our letter to you dated February 14, 2002, and in our petition.
In addition to impacts on marine mammals and endangered species (under authority of the MMPA and ESA), we believe that NMFS has a responsibility to consider the full extent of the "collateral damage" that will occur with deployment of LFA sonar, and that NMFS must consider the cumulative effects on all forms of marine life that will be affected by use of this sonar (both further testing and deployment). This is certainly a requirement of NEPA.
The precautionary principle should be adopted here as well as in the fishery management arena - deployment of LFA sonar should be approved only if the Navy can demonstrate that there will be no significant adverse effects on marine life over broad areas of the ocean at full deployment intensity levels. We do not believe NMFS should approve the Navy's deployment or even additional potentially lethal testing in marine environments until NMFS and the Navy can answer the question "what will likely be the lethal and sublethal effects of LFA sonar at full deployment intensity levels on marine life for which NMFS is the federal steward, including fish as well as marine mammals and other protected species?" Specifically for fish, we need to know
"at what decibel level does LFA sonar no longer cause direct mortality and at what lower decibel level is there no longer any debilitating injury?" Only then will we know how large an area of ocean and how much marine life could be seriously affected.
James R. Chambers