Blue Whale Deaths Surge in SoCal: Ships Strikes, Not Sonar is Cause, but Noise May Be Factor – An unprecedented surge in blue whale deaths in Southern California last year has raised concerns about shipping and noise in the busy shipping lanes there. Five blue whales were found dead on beaches last fall, and the three that were fresh enough to examine showed clear signs of being killed by ship strikes; examination of ear tissues showed now sign of hearing damage, and mid-frequency active sonar is not a factor. However, the researchers from the Santa Barbara Museum of Natural History, who performed the analysis of the whales, note that ambient noise levels in the area could have made it difficult for the whales to hear approaching ships,  Read the rest of this entry »

Public Hearings Scheduled on Supplement to Draft EIS – The Navy has released a supplement to its Draft EIS for the Hawaii Range Complex, and is holding public hearings in March to collect public comments on the new aspects. Plans still hold to release the final EIS this spring, and a Record of Decision before the summer RIMPAC exercises. The supplement addresses several areas: fine-tuning of the methodology used to assess behavioral responses to sonar sounds, a lower estimate of total sonar use, and a new preferred alternative in which future sonar use will not increase over current levels, while other training is expanded as planned.Source: Hawaii Reporter/Pacific Fleet Press Release, 2/23/08 [READ PRESS RELEASE]

Dolpin Strands on Navy Island at End of Recent Sonar Exercises – A single deep-water Northern right whale dolphin was found live-beached on San Nicolas Island on January 29, during a heavily scrutinized Naval training exercise. Navy personnel returned it to the water several times, but it did not survive. Curators at the Santa Barbara Museum of Natural History worked all night to perform a necropsy because clues are lost to rapid decomposition. The head was removed and refrigerated, then taken to the nearby Alamo Pintado Equine Medical Center for magnetic resonance imaging. “At this point, we cannot rule in or rule out sonar or any other kind of intense noise,” said Teri Rowles,  Read the rest of this entry »

Federal Judge Rejects White House Exemptions for CA Sonar (updated 2/19)– The federal judge who imposed additional safety requirements on Naval mid-frequency active sonar training off the California coast has rejected the Bush administration’s attempt to exempt the Navy from the laws she was enforcing. Central to this ruling is the fact that there is no “emergency” that warrents such intervention by the White House; the training missions at issue have been long planned, and can proceed, albeit with larger safety buffers and some geographic restrictions to avoid areas with higher numbers of whales.

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Lawsuit, Claims of Science Supression Accompany New Chukchi Lease Sale – A consortium of native and conservation groups has filed suit in federal district court, contending that an impending MMS lease sale in the Chukchi Sea did not adequately assess environmental impacts. The suit claims that the risk of an oil spill, along with the effects of seismic survey noise and the combined effects of energy development and global warming, all should recieve more scrutiny before leases are offered. Meanwhile, Public Employees for Environmental Responsibility has released emails and statements by former MMS marine mammalogist that charge the agency with changing key biological conclusions Read the rest of this entry »

Ship Noise in Santa Barbara Channel Studied – A hydrophone deployed on the ocean floor in the Santa Barbara Channel is listening in on passing ships and resident and transient whales; researchers from Scripps Institute will analyze the results in an effort to learn more about whether increasing shipping noise is hampering whale communication. Blue whales are the most commonly heard, and also the species whose calls occur in the frequency ranges dominated by ship noise. Megan McKenna, doctoral candidate at Scripps, says, “These animals evolved in a much quieter environment. You’ve got to think there has to be some threshold of them being able to use their acoustic capabilities in this noisy environment.”  Read the rest of this entry »

Court Forces Navy to Meet With NRDC to Limit LFAS Deployment, Again – In August, the Navy received a 5-year permit to operate its Low-Frequency Active Sonar system on two ships, nearly anywhere in the world, after several years during which its deployment was limited to a remote area of the West Pacific. This week, the same Federal Judge who ordered the earlier reduction in deployment issued a temporary restraining order calling on the Navy to keep its LFAS signals out of several sensitive marine areas worldwide, and to once again sit down with the NRDC and its allies to hammer out a mutually agreeable set of restrictions for the coming five years.  Read the rest of this entry »

Aussie Humpback Calving Ground Threatened by Noise and Nets – A key humpback whale calving ground off the western Australia coast is targeted for at least three disruptive developments in the coming years, prompting calls for its designation as a World Heritage Site.Camden Sound, a natural harbour north of Broome, and adjacent bays and islands are the main calving grounds for humpback whales making a 13,000km return journey from Antarctica each winter.  Read the rest of this entry »

Controlled Exposure Study Examines Beaked Whale Responses to Noise – A multi-year research program based at a Navy facility in the Bahamas is using hydrophones installed on the seafloor, along with suction-attached tags that record the sound heard by tagged whales to learn more about how dive patterns are changed when whales hear mid-frequency sonar signals. The Woods Hole periodical Oceanus featured a detailed article on this work, including pictures. Oceanus, 1/15/07 [READ ARTICLE] See also AEI’s lay summary of the cruise report from their first field season[GO THERE]

Chukchi Lease Sale Set for February, Locals Seek Delay – The US Minerals Management Service has issued notice of its first oil and gas lease sale since 1991 along Alaska’s northwest coast. The sale, scheduled for February 6, covers about 25 million acres, out to about 200 miles offshore. The sale area will not include near-shore waters ranging from about 25 miles to 50 miles from the coastline, which includes the near-shore area through which bowhead and beluga whales, as well as other marine mammals and marine birds, migrate north in the spring, and in which local communities subsistence hunt. North Slope Borough Mayor Edward Itta said, “With all the changes happening out in the Chukchi Sea, I don’t think we should be adding to the problem with offshore oil exploration.”  Read the rest of this entry »

Quiet Autonomous Gliders Promise “New Era” in Acoustic Monitoring – A major step forward in acoustic monitoring has passed its first test. “We are entering a new era of underwater sensing,” says Jim Theriault of Defence Research and Development Canada, in Dartmouth, Nova Scotia, who ran the first trial of small torpedo-shaped “gliders” as a platform for acoustic monitoring. Unlike other systems, which require a boat nearby to monitor either the tagging of whales or other autonomous vehicles, the gliders can use a satellite phone connection to return data to distant research bases. Also, the new system has enough data capability to detect not only low-frequency baleen whale calls, but also the high-frequency calls of sperm and beaked whales,  Read the rest of this entry »

Initial Cruise Report From First Controlled Exposure Studies of Beaked WhalesIan Boyd, Diane Claridge, Christopher Clark, Brandon Southall, Peter Tyack. Behavioral Response Study-2007, Cruise Report, Phase 1    A summary of the project, and the preliminary cruise report are available: [WEBSITE]During August and September, 2007, the first controlled exposure experiments aimed at learning more about the ways that beaked and pilot whales respond to exposure to mid-frequency active sonar took place in the Bahamas.  Read the rest of this entry »

Extended Near-surface Dives May Be Cause of Beaked Whale BendsWalter, M.X. Simmer, Peter L. Tyack. Repetitive shallow dives pose decompression risk in deep-diving beaked whales. Marine Mammal Science, Volume 23 Issue 4 Page 888-925, October 2007.  ScienceNow summary of paper: [WEBSITE]It is apparent that beaked whales are especially sensitive to mid-frequency sonar, but the reasons have remained elusive. This study explores a new idea about how the whales’ dive patterns may be disrupted enough to cause decompression sickness (DCS, ie “the bends”). Some have suspected that exposure to sonar may cause the whales to surface more quickly than usual, but since the whales’ lungs are collapsed in dives deeper than 70m (thus preventing nitrogen from entering the bloodstream and infiltrating into tissues where it could cause damage), it is not readily apparent how faster surfacing would cause DCS. Instead, this study looks at the “recovery” period observed in beaked whales, during which they make a series of near-surface dives before embarking on a new deep foraging dive. The researchers modeled the possible physiological effects of having this recovery period extended longer than usual. The team incorporated known physiological data into a model that charts how the bubble size might increase in the circulatory system, brain, muscles, and fat tissues when a whale dives repeatedly to between 30 and 80 meters for as long as 3 hours. The team’s model predicts that if the whales’ lungs do not collapse during a long series of shallow dives, the increased pressure can cause nitrogen bubbles to diffuse into tissues, increasing the risk of bubble formation on ascent. Such behavior may result if the whales perceive sonar transmissions as a predator:  Read the rest of this entry »

Boat Traffic Noise High Enough in Intracoastal Waterways to Raise Concerns About Hearing Damage and Making; Dolphins Seem to Avoid Weekends
Haviland-Howell, Frankel, Powel, Bocconcelli, Herman, Sayigh. Recreational boating traffic: A chronic source of anthropogenic noise in Wilmington, North Carolina Intracoastal Waterway. J. Acoust. Soc. Am. 122 (1), July 2007, p.151-160.
 This study analyzed recordings of ocean noise during the summer season (June 21-September 1) in a 100m-wide intracoastal waterway off North Carolina. The mean received sound levels (measured as RMS re 1uPa, at frequencies averaged in steps over 0-37.5kHz) ranged from 109dB at 6am to 118dB in early afternoon and back down to 111dB by 10pm. Not surprisingly, weekends and holidays were 1-3dB louder than weekdays. The frequency spectrum shows that low frequencies (below 1kHz) dominate, with significant energy remaining up to 5kHz, and lesser but still perceptible noise up to the 37.5kHz limit of the study. Dolphin observations showed a clear reduction in numbers of dolphins observed on weekends and holidays, relative to weekdays; less than half as many dolphins were observed on weekends. Noise levels in the range of 5-25kHz, the primary range of dolphin social whistles, was of particular concern. Read the rest of this entry »

Low Frequency Active Sonar Shows Less Impact on Fish than Airguns  

Popper, Halvorsen, Kane, Miller, Smith, Song, Stein, Wysocki. The effects of high-intensity, low-frequency active sonar on rainbow trout. J. Acoust. Soc. Am. 122 1 , July 2007. p. 623-635.

This study extended a previous line of research that had measured physiological impacts of seismic survey air guns on fish kept confined in a cage and exposed to the noise. This time, the research team exposed trout (which share hearing mechanisms with salmon, which are of special concern due to their endangered status) to sounds produced by low-frequency active sonar. LFA sonar uses frequencies (100-500Hz) that many fish can detect, often the range of most sensitive hearing. Fish were tested for hearing sensitivity using Auditory Brainstem Response (ABR), and some were sacrificed to check for physiological damage, including swim bladder or ear hair damage. Results indicate that fish had reduced hearing sensitivity after exposure to LFA sonar, ranging from 17-25dB at particular frequencies (i.e., sounds needed to be that much louder in order to be heard), and that the effects lasted at least 48 hours (the longest followup the study included). 

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