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Technology for the United States Navy and Marine Corps, 2000–2035: Becoming a 21st-Century Force, Volume 7 Undersea Warfare D Compliance with Laws and Policy Protecting Marine Mammals and Endangered Marine Species An issue of critical importance to today's Navy, and almost certainly to be important to -century forces, is the growing concern about the possible harmful effects of naval operations on marine life. The perceived impact might ultimately restrict operations and limit the use of both sonar systems and small underwater explosives (as little as 4 pounds of explosives). The ocean is a very efficient medium for sound propagation, especially at low frequencies. Even low-intensity sounds can propagate to very long ranges, so that the areas over which marine life might be affected—and therefore the size of the potentially affected marine populations—can be enormous. Early in 1997, the Commander in Chief of the Atlantic Fleet took unprecedented action to change a major North Atlantic Treaty Organization (NATO) operation being held in the Atlantic off the coasts of Georgia and Florida. Three northern right whales had been found dead in the Atlantic. The cause of the deaths of these animals was never determined, but the impact of their deaths generated enough public interest that the White House became involved and the Navy was ultimately forced to drastically curtail the exercise. The levels of low-frequency ambient sound in almost all the world's oceans are already dominated by anthropogenic sources, primarily shipping noise. It has been estimated that the background sound level at 100 Hz has been increasing by about 1.5 dB per decade since the advent of propeller-driven ships. Impulsive sounds from air guns or from seismic, oil, and gas exploration are also major contributors to the low-frequency background noise level. High- and mid-frequency Navy tactical and weapon sonars produce more localized disturbance, but the sound from new low-frequency ASW sonars can reach very long distances.
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Technology for the United States Navy and Marine Corps, 2000–2035: Becoming a 21st-Century Force, Volume 7 Undersea Warfare Navy weapon tests and ship shock tests generate very high intensity sounds. All of these factors have the potential to interfere with marine mammals. The issue is primarily legal as well as humanitarian. The United States has enacted a body of laws and is signatory to international agreements designed to protect marine mammals and endangered species. Protection ranges from outright bans on hunting and harvesting to more subtle prohibitions of those actions that might disturb, harass, or "take" these animals. Harassment and takes, as used here, are legal terms that are sometimes interpreted to include any activity that alters the animal's behavior in even minor ways. Behavioral modification, something as innocent as simply causing an animal to change swimming direction, is within the legal definition of take. To harass, to take, is unlawful without a permit. Under present law, the preparation of detailed environmental impact statements is usually required by the National Environmental Policy Act to assess the potential for a significant environmental effect or the possibility of a take. Even for small-scale operations and experiments, these documents are costly to prepare and can take up to a year to complete. "Take permits," permission to harass a small number of marine mammals from certain Navy at-sea experiments and operations, are also frequently required. Permits can take more than a year to process before they are granted, if they are granted at all. In some cases, elaborate environmental surveys and observations are required prior to and during the test period. Acoustic monitoring for the presence of marine mammals and for ascertaining the impact of the operation or test on the mammal or its habitat is also usually required. Compliance with the laws protecting marine mammals is expensive, time consuming, and potentially devastating to a Navy program. It can, and has, stopped programs cold. Unfortunately, the underlying scientific understanding of the effects of sound on marine life, upon which to base reasonable strategies for ensuring that these laws are not violated and that marine life is protected, does not exist. As a consequence, decisions to issue the required permits either are arbitrary or are based on very limited data and frequently incorrect assumptions. For example, the safe level of exposure to underwater acoustic energy being proposed by some is 130 dB at 1 micropascal (about 65 microwatts), a value based on a single experiment involving bowhead whales. This was the level at which 50 percent of migrating whales observed over a few days altered course to swim around an oil tower equipped with an underwater transmitter that emitted drilling-type noise. Whale tracks were altered by only a few degrees, and most whales resumed their original course after passing the tower. Whether this affected the whales in any negative way, both for the near-term and over the long term, is unknown. Whether it was anything more than an indication of hearing sensitivity is also unknown. Whether other species would react differently is unknown. Whether this event would occur at a different
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Technology for the United States Navy and Marine Corps, 2000–2035: Becoming a 21st-Century Force, Volume 7 Undersea Warfare geographic location is likewise unknown. Whether the signal type, frequency, intensity, duty cycle, or bandwidth are factors is unknown. The sensitivity of marine mammals to sonar sounds and effects of sonar sounds on these mammals simply are not known. Further, in contrast to the 130-dB level, surface ships generate from 5 to 100 watts of acoustic noise, about 175 to 190 dB. Large cruise ships can generate levels of more than 200 dB. Blue whales themselves have been observed to generate signals of nearly 190 dB. The laws are not restricted to marine mammals. The Endangered Species Act similarly protects other living marine resources. In some cases, such as that of the endangered sea turtle, for example, we do not even know the range of the animal's hearing, and we certainly do not know the threshold of its pain or the disturbance caused by underwater acoustic energy. Some endangered sea birds can dive into depths of more than 500 feet and therefore be subjected to underwater acoustic noise. Little is known of their hearing underwater or the potential damage due to the exposure. In the case of marine mammals they are known to emit sounds in the frequency band of Navy sonars, and it has been conjectured that they use these vocalizations for navigating, hunting for food, locating potential mates, and perhaps even general communications. The issue is whether or not, and to what extent, naval activities that generate underwater sound interfere with these functions. There is also concern about the effects of underwater sounds on people, both commercial and recreational divers, for example. Here too a safe exposure limit is being discussed, based on a single experiment. The problem has intensified lately, primarily as the result of an increasingly aware, vocal, and powerful environmental activist movement that is demanding rigid compliance with the laws protecting marine mammals and endangered marine species. The situation has been exacerbated by the Navy's low-frequency active acoustic ASW development programs, which are based on very high intensity sonars operating in the vocalization frequency bands of many marine mammals, especially baleen whales. As noted above, these low-frequency sonar signals are capable of very long range propagation. The Navy's development of low-frequency sonars is a result of the steady, historical reduction in submarine-radiated noise in all submarine variants—nuclear, diesel, and air independent—which has reduced the effectiveness of passive ASW and spurred the development of active methods. It is anticipated that over the next several decades, the proliferation of quiet, capable, and effective submarines through foreign sales and indigenous manufacture will result in even more reliance on active acoustics, so that the issue of compliance with environmental law will almost certainly be a major future problem for the Navy unless mitigation measures are undertaken. The Navy has had to seek permits from the National Marine Fisheries Ser-
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Technology for the United States Navy and Marine Corps, 2000–2035: Becoming a 21st-Century Force, Volume 7 Undersea Warfare vice, and in some cases the Department of the Interior, to conduct ship-shock tests (using explosive sources) and tests of prototype sonar systems, as well as exercises to develop tactics and strategies for employing LFA sonars. Weapon testing in the Gulf of Mexico has been constrained by environmental compliance. The Navy has had to prepare extensive and expensive environmental assessments and environmental impact statements for these operations and, in some instances, to alter venues and test plans. In almost all cases, regulatory decisions have been based on either anecdotal or, at best, limited scientific data and understanding. The compliance impact on a Navy operation or experiment can be debilitating. The legal costs for obtaining permission to undertake DDG 53 ship-shock tests are estimated to be $1.5 million. The tests themselves were delayed by two months following a court injunction. The cost of the delays added $3 million to the program. Similarly, tests of the LFA sonar system have been restricted to certain areas and limited to certain power levels. For environmental compliance, operational use of the SSQ 110 sonar system is highly restricted, both in geographic area and in mode of operation. Although the primary concern has focused on the use of low-frequency sonars and the acoustic energy from underwater explosions, there is an awareness that even tactical sonars interfere with many marine species. Almost nothing is known about the effects of mid-frequency, tactical sonars on marine mammals and endangered marine species. Because there is no immediate, identified threat to national security, it is unrealistic to appeal for a waiver to these environmental laws based on national security needs. Also, because environmental responsibility is an increasingly universal concern, it is entirely possible that the Navy will be prevented from developing and fielding many underwater acoustic systems required by its future missions. The health and survivability of marine life are a grave concern. The Navy has ensured its rightful role as a proper steward of ocean resources, but this role is now at odds with the full use of its own resources in the ocean environment. The Navy must comply with U.S. law and policy that safeguards the health and well-being of marine animals, but the thresholds for determining the overall health and well-being should be based on sound science. The Navy, singularly, is in a position to address this pressing national issue. Many years ago, the Navy took the lead; it now has several trained animals and has developed the technology to determine the impact of Navy operations on marine mammals and endangered marine species. Also, the Navy has a unique capability to understand the detailed propagation of underwater acoustics and therefore can ultimately ascertain the potential impacts of underwater sound on marine life. The United States has led the world in developing a legal framework for ensuring that endangered marine species are protected. It is a signatory to international agreements to limit whaling, and U.S. national laws are exemplary. It is
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Technology for the United States Navy and Marine Corps, 2000–2035: Becoming a 21st-Century Force, Volume 7 Undersea Warfare important that this conflict between responsible environmental stewardship and national security be resolved and that decisions be based on substantiated fact. Given that the Navy is a principal stakeholder in the issue, it is probably the most suitable agency to pursue this subject. Also, given that successful resolution is critical to naval operations, the Navy must pursue the R&D necessary to develop sufficient understanding of these issues to enable rational, informed decision making.
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