With the right set of ears, you could dive in the ocean and hear a full symphony of sounds: The chirps and moans of whales, the growls and grunts of seals, the background din of wind and waves, the far-reaching roar of ships, and the rumbles from ocean drilling, for example. With the increase in shipping and oil exploration over the past 30 years, the level of background noise in the ocean has risen from roughly 75 to 85 decibels.
In the next few months, two more sound-makers may join the orchestra: the North Pacific Acoustic Laboratory (NPAL, formerly known as the Acoustic Thermometry of Ocean Climate Project Phase II) under the aegis of California’s Scripps Institution of Oceanography and the Navy’s Surveillance Towed Array Sensor System (SURTASS) Low-Frequency-Active (LFA) sonar. Those noises have been causing plenty of ruckus above water, too. Their potential deployment has turned a question that was previously academic- What do marine animals hear? – into a controversy pitting the long-term strategic plans of the Navy and global warming researchers against passionate dissenters who feel that these technologies have already harmed vulnerable marine animals.
The low-down on low-frequency
The ocean is an acoustic environment. Sound waves travel roughly five times faster through water than through air and many times farther. (Sound intensity is measured in decibels, or dB, which is a logarithmic scale. So a rise of 3 dB represents about a doubling in sound intensity, 10 dB would be a tenfold increase.)
High frequency, or high-pitched, noise-even at high decibel levels-is generally a local problem, but low frequency sounds (below 1,000 hertz) can have far-reaching effects. That’s why you hear the bass but not the vocals from your neighbor’s stereo. Combining high decibels and low frequency makes for a loud and far-traveling sound, the very type generated by both NPAL and LFA. No one doubts that hovering next to one of these noisemakers will cause ear damage. But how far is safe? And what are the long-term effects, if any, on animals that get in the way of these sound waves? Despite the publication of a voluminous environmental impact statement (EIS) for each of these projects, these questions remain the subject of heated debate.
“The Navy has been killing whales for a long time. But usually you’re never going to know it, because they’re out in the middle of the ocean.” – Marsha Green, whale researcher
Already, a wide range of marine animals is regularly exposed to loud sounds. Little is known about the consequences of these exposures. Nor does any law specifically address ocean noise. The closest thing is the Marine Mammal Protection Act of 1972, administered by the National Marine Fisheries Service (NMFS). Shipping noise is by far the loudest on-going, low-frequency sound in the ocean. Ships emit low-frequency rumbles that can penetrate the open ocean far beyond shipping lanes. A modern supertanker traveling at about 20 miles per hour fills the frequency band below 500 hertz with a steady blare, with source levels as high as 190 dB. Yet ships are the least regulated of the noise-makers. While NMFS reviews permit applications from scientists seeking to emit noise in the course of their research, supertankers thunder in and out of ports with impunity.
In 1995, NMFS recognized the need to address the growing clamor and created the Acoustics Program (part of the Office of Protected Resources), charged with defining what sounds cause takes in marine mammals and endangered species. (The term “take,” as defined by the Marine Mammal Protection Act, means to harass, hunt, capture, or kill, or to attempt to harass, hunt, capture, or kill.) So far, the program has acquired data on the hearing ability of just 10 species of marine mammals and one species of marine turtle. The effect that sound has is another story.
A deaf whale is a dead whale
For whales, dolphins, and porpoises, sound is their most important tool. It allows them to navigate, feed, mate, and communicate in the dark depths of the ocean. Their ears can be extraordinarily sensitive. For instance, one study found that humpback whales responded to the calls of their own from as far as 2.8 kilometers away. The lowest received tone that still sparked a response was about 104 dB. Finback whales have also been found to respond to the distant vocalizations of their kind.
One of the few people who specifically studies the ears and hearing of marine animals is Darlene Ketten, who works at the Woods Hole Oceanographic Institution and the department of Otology and Laryngology at Harvard Medical School. Hearing ability is measured in two ways, she explains. “You can ask them what they hear by training them to respond when they can detect a sound.” Complex and time-consuming, this has been done with a few marine mammals-mostly dolphins-raised in captivity. The second method measures the auditory brainstem response (ABR) of an individual. The hearing of human newborns is routinely tested this way. The procedure has been conducted on some marine mammals, such as dolphins and seals. “But it’s problematic,” she says. “The bigger the animal, the harder it is to get a clear signal.” So far, no successful ABR has been conducted on a baleen whale.
So Ketten has come up with a third method. She’s created three-dimensional anatomical models of a variety of marine mammal ears, which help her estimate hearing abilities. With this method, she has determined that baleen whales have an extraordinary hearing range, detecting a dozen octaves compared to the paltry eight humans can hear.
But knowing what an animal can hear is just the first step. The next is finding out how sounds might affect them. At the very least, marine mammals exposed to loud noises may suffer temporary hearing loss. For instance, harbor seals, which hear best at the higher frequency of 10,000 hertz, can experience hearing loss for several hours after 20-minute exposure to 500 hertz sounds of 130 dB, according to experiments by Ron Schusterman, an animal behaviorist at the University of California, Santa Cruz.
Marine biologist Peter Tyack from Woods Hole did a study off the California coast, playing recordings of undersea drilling sounds to gray whales migrating south. The whales changed course to avoid noise levels above about 120 dB. During testing of LFA, researchers found that when a source level of 170 dB was located in the migratory path of gray whales, the animals steered around the source by several hundred meters. When the level was increased to 185 dB, and still in the migratory path, the animals changed course so as to avoid passing within a kilometer of the source. In both cases, the whales seemed to be moving far enough away from the sources so that they would hear noises no greater than 140 dB. However, when the sound source was placed outside their migratory path, they appeared to engage in less avoidance behavior, even when the sound source levels were 185 dB and 200 dB. For these whales, at least, it was more disturbing to hear a strange sound coming from within their migratory path than a similar or even louder sound coming from outside. So an animal’s response to noise may also depend on the location of the sound.
The nature of the noise may make a difference, too. Some marine animals can contend with loud sounds. Humpbacks can sing as loud as 170 dB, blue whales at 188 dB. This suggests that whales may be tolerant of their own loud sounds. But could other sounds drown out the swishing from prey animals they want to eat, or keep a lost calf from finding its mother?
In the Natural Resources Defense Council publication “Sounding the Depths,” marine biologist Sylvia Earle describes the problem eloquently: “Undersea noise pollution is like the deaths of a thousand cuts. Each sound in itself may not be a matter of critical concern, but taken all together, the noise from shipping, seismic surveys, and military activity is creating a totally different environment than existed even 50 years ago.” So while the noise of human activity might not cause hearing damage, some creatures of the sea may simply have a harder time hearing and being heard. And that has broader implications, such as the disturbance of breeding, feeding, and migration. The potential effects are most significant for baleen whales and seals, which hear well at low frequencies.
Lethal noise
So far, most of the research for NPAL (ATOC) and LFA has focused on whales. And with good reason. All populations of humpback, blue, fin, gray, and sperm whales are listed as endangered. But they’re not the only marine animals at risk. In just the Hawaiian waters where NPAL and LFA may boom live endangered monk seals and spinner dolphins and five protected species of sea turtles. Ketten suspects that more than just whales may be affected by low frequency sound. “There’s some species of seals, which should be considered.” She is also studying the hearing of sea turtles. A few studies suggest that they are capable of hearing low-pitched sounds.
Some environmentalists and scientists believe studies conducted for the environmental impact statements for the two projects have been too narrow-both in the number of species examined and in the numbers of individual animals tracked. Nor can the results be extrapolated to other species. Marine mammals are acoustically diverse, with wide variations in ear anatomy, range, and sensitivity, according to Ketten. Baleen whales, for example, hear well into the infrasonic range-less than 50 Hz-while dolphins hear well into the ultrasonic range-greater than 20,000 Hz. And while beaked whales have ears that look ultrasonic, they can probably hear tones below 1,000 Hz, although, adds Ketten, “it isn’t going to be in their best frequency range.”
In addition, there’s evidence that sounds might be trickling down the food chain. Most fish species have good detection in the low frequency range. Studies on fish are sparse, but compelling. For example, growth rates for two fish species, sheepshead minnows and killifish, were significantly lower in aquariums exposed to noise 20 to 30 dB above ambient levels in the natural habitat. A similar effect was also found for shrimp.
Perhaps the most dramatic event suggesting that low-frequency sonar may be harmful occurred in May 1996 when at least 12 Cuvier’s beaked whales beached themselves in the Mediterranean-just as a NATO vessel, “The Alliance,” was conducting tests on a low-frequency active sonar system in the area. The signals of just under 230 decibels lasted 4 seconds and were repeated once every minute. Scientists later estimated that the whales received levels as high as 150 to 160 dB. They also noted that beaching for this type of whale is extremely rare. In addition, the stranding involved individuals scattered across an area rather than a single group. In a 1998 article in the science journal Nature, biologist Alexandros Frantzis calculated that the probability of the mass stranding occurring for reasons other than the sonar testing was less than 0.07 percent.
Another suspicious incident involving active sonar-albeit mid-frequency-took place in March 2000, when 17 marine mammals of various species beached in the Bahamas. At least eight whales died. The animals, most of which were deep-sea-dwelling beaked whales in otherwise healthy condition, suffered hemorrhages. Some of the whales had eyes that were bleeding. A report by biologists hired by NMFS stated that the injuries to the beaked whales were “all consistent with an intense acoustic or pressure event.” During the beachings, the Navy had been testing its Littoral Warfare Advanced Development (LWAD) system, which emits mid-frequency tones at or below 235 decibels and thus does not cover as much distance as those from an LFA system. When the Navy sent its Overseas Environmental Assessment to NMFS’s northeast regional office on April 21, 2000, NMFS responded in a letter, stating “we are not able to concur with your determination that the proposed action is not likely to adversely affect listed species.” Planned tests of the LWAD system scheduled to begin off New York and New Jersey had to be canceled.
LFA: Active defense
Active sonar has been used since World War II, but the SURTASS LFA sonar is unique because its low frequencies allow the Navy to detect submarines over ranges more than five times as large as other systems. The Navy plans to deploy the system in about 80 percent of the world’s oceans, with two vessels each in the Pacific and Atlantic oceans. Although only one vessel is currently in operation-the R/V Cory Chouest stationed at Pearl Harbor-the Navy is scheduled to have four in deployment by the end of 2004. The Navy claims it needs LFA to replace its old passive sonar system in order to detect new, quieter submarines.
“What the Navy has done is try to say that nothing important happens until 180 dB.” — Lanny Sinken, Hilo attorney
How it works: SURTASS itself is a passive system that uses a string of hydrophones to detect noises produced by submarines. LFA is an enhancement to SURTASS that adds the ability to broadcast sounds-the “active” part of the sonar. Eighteen loudspeakers, each about the size of a small bathtub, are lowered from the vessel’s hull between 60 and 180 meters down. The speakers broadcast at a level of about 230 dB in tandem, creating from a few hundred meters away a focused beam of low frequency (100 to 500 Hz) tones. According to the Navy’s EIS, it intends to broadcast pulses lasting up to 50 seconds, repeating them at a rate between 0 and 10 minutes. (Specific values are all classified.)
The beam of sound extends for hundreds of miles, dipping and rising toward the surface in a wave pattern that radiates from the ship like a fan. Within these wave patterns, the tones can reach as high as 140 dB from more than 300 miles away. In between the wave patterns, the noise can still be heard, but at much lower intensities. The reflections of those sounds off submarines or other objects can then be picked up by the hydrophones. The Navy anticipates that a typical at-sea mission will occur over a 30-day period and will be made up of two nine-day exercise segments, transmitting a maximum of four hours each day.
According to the Federation of American Scientists, SURTASS LFA sonar has been tested about 25 times for a total of some 7,500 hours around the world since the early 1980s when development began. NATO is also testing LFA sonar. Joel Reynolds, senior attorney with the NRDC, believes the U.S. Navy conducted at least 22 separate operations without environmental assessments or small take exemptions under the Marine Mammal Protection Act before 1994. And to date, the Navy has spent more than $300 million researching and testing the system. Critics of the plan suggest that the EIS was prepared in such a way to justify the Navy’s lengthy and expensive investment. For example, neither the Bahamas nor Mediterranean stranding incidents were really addressed in the EIS. In fact, in the March 19, 2001, issue of the Federal Register, NMFS responded to a comment from the Draft EIS, writing that “there is no evidence linking SURTASS LFA sonar transmissions to any stranding event.”
For most of its life, the SURTASS-LFA project has been shrouded in secrecy. It wasn’t until the NRDC threatened the Navy with a lawsuit that the curtain began to lift. As a result, on July 18,1996, the Navy published a Notice of Intent to prepare the SURTASS LFA Sonar Environmental Impact Statement in the Federal Register. Although the notice stated that the assessment of possible environmental impacts within U.S. territorial waters would be done pursuant to the National Environmental Policy Act and that assessment of possible environmental impacts outside U.S. waters would be done pursuant to Environmental Effects Abroad of Major Federal Actions, it made no mention of other federal laws that would have to be considered-notably the Endangered Species Act and the Marine Mammal Protection Act. Both prohibit the taking of marine mammals without the appropriate authorization. Nor did the notice indicate the sonar’s output level, the depth at which the sounds will be broadcast, or how often and for what length of time the system is expected to be used.
In response to the notice, the Marine Mammal Commission, a federal agency created to help protect marine mammals, issued a letter to the Navy on September 4, 1996, outlining these inadequacies as well as noting potential dangers of the system. These included “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 and, if the disruption is severe, frequent, or long-lasting, possible decreases in both individual survival and productivity and in population size and productivity.”
In February of 1997, the SURTASS LFA Scientific Working Group held its first meeting to determine how they were going to assess the sonar’s effects on marine life. Yet again, gaps existed. For one, the group decided to focus on only four species of whales.
The Marine Mammal Commission, in its 1997 annual report to Congress, repeated its apprehension concerning the SURTASS LFA system. On September 8, 1997, NMFS issued a permit authorizing the “harassment” of several marine species to Christopher Clark, director of the bioacoustics lab at Cornell University, so he could investigate the potential effects of LFA on marine mammals. A three-phase experiment was developed. During each, researchers played pulses of a simulated LFA signal-at lower intensities, however, than planned deployment levels.
Phase I took place from September 18 through October 5, 1997, and focused on observing the responses of blue and fin whales off the coast of southern California. The 42-second pulses were repeated once every six to 10 minutes over a two to three hour period, with received levels between 115 and 148 dB. Only two fin whales were successfully tagged with time-depth-recorders to quantify diving behavior during testing. And only “seven focal animals (1 blue and 6 fin whales)” were “under close observationÉ. during LFA playback.” Not surprisingly, the researchers found “no immediately obvious responses.” There were, however, extensive acoustic recordings indicating that vocalization decreased. The Navy’s “Quick Look” report found that blue whales decreased vocalizations by 50% and fins whales by 30% when the sound was on. Later reports by the Navy, however, concluded that upon closer analysis, the differences were not statically significant.
In January of 1998, Phase II testing proceeded off the coast of central California and focused on gray whales. As described earlier, the whales deviated from their migration paths when the sound source was within their route. Tracking lasted 18 days and included the paths of about 1,400 migrating whales. A brief note in the report mentions that an observer monitoring sea otters found that their foraging success was reduced by 11 percent and dive time increased by a similar amount during testing. It concluded that “there is at least an 80% probability that this reduction in success was not a random event.”
During March 1998, Phase III looked at humpback whales off the coast of Kona-a favorite breeding and calving area just a few miles from the border of the Hawaiian Humpback Whale National Marine Sanctuary. Tests were conducted at source levels between 185 and 203 dB. The sounds were slowly ramped up and did not exceed a received level of 155 dB. The Navy’s technical report noted that out of 17 singing whales followed, 10 stopped during playbacks. Of those, it concluded that four stopped to join another singer. So only six may have stopped as a result of the playbacks; and thus the effect was not significant since just as many kept singing as stopped.
When looking at those that continued to sing, researchers found a slightly different outcome. In an article in the June 22, 2000, issue of Nature-the first of the Navy-funded LFA-tests to be published in a peer-reviewed journal-Tyack and his colleagues reported that male humpbacks altered their singing behavior when they were exposed to LFA sonar. On average, humpback songs were 29 percent longer during playbacks. Song duration returned to normal after exposure. They write, “Since the song of these whales is associated with reproduction, widespread alteration of their singing behavior could affect demographic patterns.” They concluded by suggesting that the whales sang longer to compensate for the interference.
But this wasn’t enough. In spite of being published in a prestigious peer-reviewed journal and being authored by the Navy’s own team, the finding was later dismissed by the Navy, says Marsha Green, a whale researcher at Albright College in Pennsylvania and co-founder of the Ocean Mammal Institute. According to Green, at a meeting she attended with Navy personnel and the congressional delegation of Maine (one of the states most actively opposed to LFA sonar), Kurt Fistrup, assistant director of bioacoustic research at the Cornell Lab of Ornithology, discounted the significance of the increase in song length. “Obviously nothing is going to convince them,” she says. “They’ve systematically dismissed any shred of evidence that this has any impact, including peer-reviewed data from their own research team.”
“There’s some species of seals, which should be considered.” — Darlene Ketten, etiologist
As a further example, the Navy has pointed to aerial surveys of Hawaiian waters conducted by Joseph Mobley, from the University of Hawai`i in West O`ahu, as evidence that whales did not leave during Phase III testing at Keahole Point. However, Mobley’s randomly chosen survey grid did not include Keahole Point. His surveys covering the whole state of Hawai`i for the 1993, 1995, 1998, and 2000 seasons indicate that the overall Hawaiian population of humpbacks has been increasing at a rate of about 7 percent each year, but as Mobley notes, “our surveys are designed more to look at population trends for the whole population around all the major islands. They aren’t really designed for saying that whales specifically off Keahole Point or any other region have shifted.”
During 1998, four lawsuits were filed in federal court in Honolulu against the deployment and/or testing of LFA, claiming that the NMFS permit under which the tests were being conducted had said that tests would be suspended if whales left the area or if acute behavioral responses occurred. NMFS did not suspend the tests despite some whales stopping singing. All lawsuits were dismissed. What’s most striking, according to Hilo-based lawyer Lanny Sinken, who has filed three lawsuits concerning LFA use, is that the evidence and testimony presented were never addressed. “It was actively avoided. They simply don’t include it [in the EIS].”
The evidence and testimony included:
-Statements by Green, who for nearly 20 years has been studying Hawai`i’s humpback whales: Results of her work off Maui show that when the intensity of a boat’s engine exceeds just 120 dB, humpbacks swim away up to three times faster than they swim around quiet boats. They also decrease their social vocalizations around loud engines. Lowered energy levels from trying to avoid loud sonar sounds and the resulting stress could make their avoidance of predators and their intense 3,000-mile migration north in March more difficult, she says.
-Testimony by Linda Weilgart, a biologist from Dalhousie University who has been studying whale vocalization for more than 16 years: She cited studies showing that gray and bowhead whales as well as several fish species “clearly avoid sounds at an average received intensity of 120 dB.” She also pointed to a study of whale calving lagoons in Baja where mothers and calves fled from noisy lagoons for extended periods of time, which she said, resulted in a “dramatically lower number of calves born that year.”
-Anecdotal evidence from whale tour operators and fishermen, claiming that whales had disappeared from the testing area. And from a snorkeler, Chris Reid, who was in the water on March 10th during a 120 decibel broadcast and emerged with symptoms that a doctor later described as comparable to acute trauma. á
-Two whale calves and one dolphin calf that were found abandoned in the testing area by Ocean Mammal Institute researchers-an event that Green says is “unheard of.” They tracked one of the lone humpback calves on March 9, 1998, for 5 hours, during which it breached more than 230 times.
In July 1999, the Navy published the Draft EIS, which concluded that the sounds had “no lasting biological significance.” But critics point out that the tests only looked for immediate effects-occurring over a period of at most one month-in behavior resulting from an exposure level of 155 dB or less, well below actual deployment levels.
Nonetheless, the process continued, and on August 12, the Navy applied to the NMFS for a permit to allow an incidental take of marine mammals for five years. The Navy’s request states that a 180 dB sound field will extend for 1 km around the ship, which translates into a sound source of about 215 dB.
After heated public hearings and a lawsuit filed on February 29, 2000, by several Hawaiian environmental groups, the Hawai`i Green Party, and Hawai`i County Council member Julie Jacobson in the Federal District Court in Honolulu, the Navy agreed in court on June 15, 2000 not to test or deploy its LFA sonar system until it had prepared a final environmental impact statement addressing comments raised by the draft EIS. The Navy released the final EIS in late January 2001.
NMFS published its proposed rule just two months later, on March 19. The rule would allow the Navy a five-year “incidental take permit” under the Marine Mammal Protection Act. New additions include a proposal to establish “Offshore Biologically Important Areas,” where marine mammals congregate in large numbers and SURTASS LFA sonar ships could not operate. To date, four sites have been proposed: Portions of the U.S. northeast coast and Antarctic waters, the Costa Rica Dome in the eastern Pacific Ocean, and Penguin Bank, the shallow shelf that extends from the western end of Molokai. Nor will the system operate in coastal waters (22 km from coastline) or polar seas. So according to the Navy, sounds greater than 150 dB should not occur within Hawaiian state waters, which extends three miles from the coast.
NMFS anticipates that it will be at least September before it decides whether to grant the Navy a “take permit.”
Missing logic
To opponents, one of the most puzzling conclusions of the EIS is the establishment of 180 dB as the level at which harm begins for 95 percent of marine mammals. “It’s arbitrary,” says Green. “They have no data to show that it’s OK. In fact, the data that we do have shows exactly the opposite-that whales strand at about 150 to 155 dB. All the literature shows that many different whales species start to avoid sounds at about 120 dB. So to conclude that it’s safe up to 180 dB is just not responsible scientific work.”
The choice of 180 db makes more sense once one considers the Navy’s deployment requirements and conditions NMFS has proposed placing on the Navy’s operations. NMFS has determined that within a radius of 1 kilometer, the Navy will be able to see about 80 percent of the time if marine mammals are present – and if they are, no operation is allowed. (If the radius is expanded to 2 km, the estimated success rate of locating marine mammals in the area drops to 50 percent.)
But to make SURTASS LFA work, the Navy has to broadcast at a level of at least 215 dB. And at that level, the sound heard at a distance of 1 km is 180 dB.
“What the Navy has done is try to say that nothing important happens until 180 dB,” says Sinken. The NMFS is “saying in the proposed rule is that it’s too hard for them to see anything beyond 1km, so we won’t ask them about it. We’ll just hold them to the 1 km and that somehow is going to mitigate biologically important effects.”
Besides extrapolating to other species from studies on a limited number of marine mammals and extrapolating effects observed from tests done below full operational level, the deployment has another flaw: The proposed ruling would allow transmissions at night, in fog, and in high seas, all of which would make it more difficult to spot animals in the 1 km field. And during times of threat or warfare, all bets are off. None of the restrictions apply.
In its EIS, the Navy acknowledges that “[d]ata regarding underwater hearing capabilities of marine animals are rare and limited to a few of the smaller species that make convenient subjects in captivity.” It goes on to note that “[t]hese data gaps have necessitated the use of various models and extrapolations in order to provide a rational basis for the assessment of potential risks from exposure to LF sounds.”
“Data regarding underwater hearing capabilities of marine animals are rare and limited to a few of the smaller species that make convenient subjects in captivity.” — Navy EIS for SURTASS LFA
One of the biggest criticisms continues to be that the studies focused only on short-term, easily-observable reactions. In response, NMFS and Navy spokesmen say that the vessel will be in a single area for a short period of time. However, nothing in the ruling prohibits the Navy from repeatedly deploying LFA in one spot. In fact, the very nature of the system implies that the Navy will concentrate on areas that may be a threat. “They’re not going to be just wandering about in the Pacific, hoping to find a submarine,” says Sinken.
The proposed take permit does not allow for the deaths or strandings of marine mammals, but Green observes that there is no way to determine if deaths do occur. “What a lot of us have been saying is that the navy has been killing whales for a long time,” Green says. “But usually you’re never going to know it, because they’re out in the middle of the ocean. The animal dies and it sinks to the bottom or are eaten by sharks. So the whole idea of monitoring for potential effects is absurd. I think we just see the tip of the iceberg with the strandings.”
The very idea that the Navy should be granted a small take exemption under the Marine Mammal Protection Act has been challenged. In the NRDC’s letter commenting on the final EIS, Joel Reynolds writes: The NMFS “would grant a ‘small take’ permit to a program whose ‘takes’ of marine mammals are in every sense global and in no sense ‘small.’ÉTo be eligible for exemption, activities must (1) occur within ‘a specified geographic region’ and (2) involve incidental take of only ‘small numbers of a marine mammal species or population stock.”
He continues, “Even using the Navy’s figures, the numbers of marine mammals potentially affected by the system are extraordinary. For example, during each year of operation and with all of the mitigation and monitoring the Navy has proposed, more than 16 percent of blue whales in the eastern North Atlantic, more than 10 percent of beaked whales in the Mediterranean Sea, more than 12 percent of elephant seals in the eastern North Pacific will be ‘affected.'”
As the NMFS works on its rulings, opponents are assembling a battle plan. “We’re trying to find studies on the effects of sound on ocean life,” explains Green. “If we can show that that kind of sound level affects endangered species, under the Endangered Species Act you can’t do it.” Green is also looking at effects on some of the ocean’s smallest inhabitants: plankton. Plankton are “the bottom of the food chain,” she says. “If plankton are affected, everything goes in the ocean.”
— Gretel H. Schueller
Volume 12, Number 2 August 2001