By Alicia Chang and Judy Watson, The Associated Press, December 15, 2013
 |
| Save whales and dolphins from U.S. navy sonar |
SAN DIEGO — The U.S. Navy plans to increase sonar testing over the next five years, even as research it funded reveals worrying signs that the loud underwater noise could disturb whales and dolphins.
Reported mass strandings of certain whale species have increased worldwide since the military started using sonar half a century ago. Scientists think the sounds scare animals into shallow waters where they can become disoriented and wash ashore, but technology capable of close monitoring has emerged only in about the last decade.
Aside from strandings, biologists are concerned marine mammals could suffer prolonged stress from changes in diving, feeding and communication.
Two recent studies off the Southern California coast found that certain endangered blue whales and beaked whales stopped feeding and fled from recordings of sounds similar to military sonar.
'Warning flag'
Beaked whales are highly sensitive to sound and account for the majority of beachings near military exercises. Scientists, however, were surprised by the reaction of blue whales — the world's largest animal — long thought to be immune to the high-pitched sounds. It's unclear how the change in behavior would affect the overall population, estimated at between 5,000 and 12,000 animals.
Beaked whales are highly sensitive to sound and account for the majority of beachings near military exercises. Scientists, however, were surprised by the reaction of blue whales — the world's largest animal — long thought to be immune to the high-pitched sounds. It's unclear how the change in behavior would affect the overall population, estimated at between 5,000 and 12,000 animals.
The studies involved only a small group of tagged whales and noise levels were less intense than what's used by the Navy. Shy species, such as the Cuvier's beaked whale that can dive 3,000 feet below the surface, have taken years to find and monitor.
"This is a warning flag and deserves more research," said Stanford University biologist Jeremy Goldbogen, who led the blue whale study published this summer in the Proceedings of the Royal Society B.
Both studies were done by a team of independent scientists as part of a Navy-funded, five-year project launched in 2010 to understand how sonar affects marine mammals.
Training seen as vital
Navy officials say it's vital to national security that sailors receive sonar training in real-life conditions.
Navy officials say it's vital to national security that sailors receive sonar training in real-life conditions.
Environmentalists have long claimed that sonar harms marine mammals, which use acoustics to mate and forage. They want more protections and accuse the Navy of rushing to obtain five-year permits under the Marine Mammal Protection Act from the National Marine Fisheries Service to increase its sonar testing in U.S. waters without considering the latest science.
"If you deafen a marine mammal for even a short period time, you are affecting its ability to survive," said Michael Jasny of the Natural Resources Defense Council, whose group has sued to force the Navy to add more protections.
A federal judge in September ruled that marine fisheries officials did not consider the best available data when it approved permits last year for operations stretching from Northern California to the Canadian border. The agency has until August to reassess how it will protect ocean life.
The California Coastal Commission also rejected the Navy's five-year plan for exercises that would start in January off Southern California. However, the state agency does not have the power to block the drills, and the Navy has ignored the agency's requested protections in the past.
Deaths and injuries estimated
The Navy estimates that its activities could inadvertently kill 186 whales and dolphins off the East Coast and 155 off Hawaii and Southern California, mostly from explosives.
The Navy estimates that its activities could inadvertently kill 186 whales and dolphins off the East Coast and 155 off Hawaii and Southern California, mostly from explosives.
It calculates more than 11,000 serious injuries off the East Coast and 2,000 off Hawaii and Southern California, along with nearly 2 million minor injuries, such as temporary hearing loss, off each coast. It also predicts marine mammals might change their behavior — such as swimming in a different direction — in 27 million instances.
Navy officials said they considered the latest research available, including the two recent studies, but none proves the activities cause significant harm to the marine populations.
Navy spokesman Kenneth Hess emphasized that the studies published this summer involved a small group of animals, and some did not react, indicating the sound's distance and other context may play a role. The Navy uses simulators where possible.
"Overall, the activities we propose are very similar to the training and testing we have done in these areas for the past 60 years, and we have not seen major impacts on marine mammals from these activities," Hess said.
Decision expected this month
Until now, studies have measured animals' response based on recordings similar to military sonar or depended on the tagging of marine mammals during Navy at-sea training in which scientists could not control the distance or intensity. For the first time, researchers coordinating with the Navy are conducting experiments using mid-frequency active sonar transmissions from ships. This past summer, they tagged six whales and dolphins off the Southern California coast. Those results are still being analyzed.
Until now, studies have measured animals' response based on recordings similar to military sonar or depended on the tagging of marine mammals during Navy at-sea training in which scientists could not control the distance or intensity. For the first time, researchers coordinating with the Navy are conducting experiments using mid-frequency active sonar transmissions from ships. This past summer, they tagged six whales and dolphins off the Southern California coast. Those results are still being analyzed.
Marine fisheries officials last month granted the Navy its permit for activities in the Atlantic and Gulf of Mexico, on the condition that the military review the latest science yearly. The Navy must cease exercises if mammals are spotted nearby, and establish a response plan to a mass stranding. A decision on the Pacific permit is expected to be announced this month.
Some scientists want the Navy to create safety zones that would guarantee no high-intensity sonar activity near marine sanctuaries and areas with a high concentration of blue, fin and gray whales seasonally.
"There are the ocean equivalent of deserts where sonar exercises could be conducted which would be vastly safer," said Lindy Weilgart, a biologist at Dalhousie University in Canada who doesn't receive any Navy funding.
* * *
By The Guardian, July 3, 2013Whales flee from the loud military sonar used by navies to hunt submarines, new research has proven for the first time. The studies provide a missing link in the puzzle that has connected naval exercises around the world to unusual mass strandings of whales and dolphins.
Beaked whales, the most common casualty of the strandings, were shown to be highly sensitive to sonar. But the research also revealed unexpectedly that blue whales, the largest animals on Earth and whose population has plummeted by 95% in the last century, also abandoned feeding and swam rapidly away from sonar noise.
The strong response observed in the beaked whales occurred at noise levels well below those allowed for US navy exercises. "This result has to be taken into consideration by regulators and those planning naval exercises," said Stacy DeRuiter, at the University of St Andrews in Scotland, who led one of the teams.
"For whales and dolphins, listening is as important as seeing is for humans – they communicate, locate food, and navigate using sound," said Sarah Dolman, at charity Whale and Dolphin Conservation. "Noise pollution threatens vulnerable populations, driving them away from areas important to their survival, and at worst injuring or even causing the deaths of some whales and dolphins." Dolman said there were no accepted international standards regarding noise pollution and there was an urgent need to re-evaluate the environmental impacts of military activities.
The US Navy part-funded the new studies but said the findings only showed behavioural responses to sonar, not actual harm. Nonetheless, Kenneth Hess, a US Navy spokesman, said permit conditions for naval exercises were reviewed annually and added: "We will evaluate the effectiveness of our marine mammal protective measures in light of new research findings."
Unusual mass strandings, where multiple species of whale and dolphin beach at several locations at once, have soared since the introduction of military sonar in the 1950s and can be fatal. The strandings occur every year and major recent events saw up to 15 animals beached in the Canary Islands, the Bahamas and Greece. In May, the naval activity was found to be the most probable cause of the deaths of at least 26 short-beaked common dolphins in Falmouth Bay, Cornwall in June 2008.
Beaked whales are the most common species affected by unusual mass strandings, perhaps because their shy nature makes them more easily scared by noises that they may interpret as killer whale sounds. Researchers used suction cups to attach digital devices to Cuvier's beaked whales off the coast of Southern California to measure the noise they were exposed to and their response.
When a simulated military sonar signal was sounded at 200dB and between 3km and 10km away, the whales initially stopped feeding and swimming. They then swam rapidly away from the noise and some performed unusually deep and long dives. "The missing piece of the puzzle was how whales changed their behaviour and how that led to mass strandings," said DeRuiter. She added that they also stopped feeding for 6-7 hours, which is unusual. "If they miss out on food, they will be less healthy," she said, noting that where populations have been measured, numbers of Cuvier's beaked whales are declining.
A second study, also off Southern California, estimated that a blue whale spooked by the sonar missed out on over a tonne of krill, about a day's worth of food. "Blue whales rely on large aggregations of dense krill to sustain their extreme body size, so they continuously dive and feed throughout the day when high-density prey patches are present," said Jeremy Goldbogen, at Cascadia Research, a non-profit US research organisation in Olympia, Washington. "Because of this, we suggest that sonar-induced disruption of feeding could have significant and previously undocumented impacts on individual baleen whale fitness and the health of their populations."
A spokesman for the UK's Royal Navy said: "The Royal Navy already limits its use of sonar around whales. We are committed to taking all reasonable and practical measures to protect the environment and mitigate effects on marine mammals. This new research will be taken into account in the regular review of MoD active sonar mitigation procedures."
No comments:
Post a Comment