Been wondering what’s up with the great “Sonar Kills Whales”/”Everything’s Fine, Just Go Away” rhetorical battle between NRDC and the Navy? As you might suspect, the reality is not nearly so neatly defined as either of them might suggest….and if you’re up for digging into it more deeply, the Acoustic Ecology Institute has just posted an AEI FactCheck that explores three key questions:

• Dead Whales: How Common?
• Behavioral Reactions: Millions of Whales Affected, or Negligible Impact
• Additional Mitigation: Common Sense Precautions or Undermining Sailor Safety?

There’s a fair dose of decoding science and regulatory details in this document, as well as acknowledgment of the underlying unspoken ethical questions that lead to radically different perspectives on the same data.

Check it out at
http://www.AcousticEcology.org/srSonarFactCheck.html
AEI is a resource/information center for sound-related environmental issues, run by editor/writer Jim Cummings (yup, that’s me…). We’ve some how managed to become friends with top scientists and agency staff, major environmental groups, and even a few folks in the Navy and oil and gas industry. More at http://AEInews.org

As a new UK Navy report suggests that beaked whales made “potentially very significant” behavioral changes in response to mid-frequency active sonar signals, a team of scientists has just completed a pilot study that involved monitoring the detailed behavior of whales during a major Naval exercise. The UK military report details observations of whale activity during Operation Anglo-Saxon 06, a submarine war-games exercise in 2006. Produced for the UK’s Defence Science and Technology Laboratory, the study used an array of hydrophones to listen for whale sounds during the war games. Across the course of the exercise, the number of whale recordings dropped from over 200 to less than 50. “Beaked whale species appear to cease vocalizing and foraging for food in the area around active sonar transmissions,” said the report.  Read the rest of this entry »

For the first time, researchers will have the chance to see in detail how beaked whales respond to actual military active sonar exercises, thanks to two studies taking place during the biannual RIMPAC exercises around Hawaii this month. RIMPAC, the world’s largest multi-national naval exercise, involves 20,000 troops from ten countries, and runs through July. One team will be tracking dive patterns only on 30-35 whales, while researchers from another team will attach suction-mounted D-tags to beaked whales; the tags remain attached for several hours before falling off and rising to the surface for retrieval. While attached, the tags track the dive patterns of the whales, as well as recording all sounds, so that researchers can hear what sound level triggered any observed behavioral changes. D-tag studies have been an increasingly valuable research tool over the past several years, but until now, had been used only in controlled experimental settings (with researchers making or playing sounds in the vicinity), rather than in “real world” settings. Sources: AP, 7/3/08 [READ ARTICLE]

Caroline Weir. Overt Responses of Humpback Whales (Megaptera novaeangliae), Sperm Whales (Physeter macrocephalus), and Atlantic Spotted Dolphins (Stellena frontalis) to Seismic Exploration off Angola. Aquatic Mammals 2008, 34 (1), 71-83.

During ten months of seismic surveys off the Angola coast, 2769 hours of marine mammal observations were made from a survey vessel, seeking to determine whether marine mammals avoided the airgun noise. This study did not examine subtler responses, such as dive patterns or call rates, but simply tracked sighting rates and distances. The total number of marine mammal sightings was rather small, given the long timeframe (66 humpbacks, 124 sperm whales, 17 dolphins); the author does not offer any hints as to whether populations are simply low in that area, or whether observations were limited for any other reason (weather, single observer, high seas, etc.). Airguns were active roughly half the time, providing a balanced set of data to look at. The mean distance at which all species were seen was greater when airguns were active than when they were silent, though only the dolphins showed a statistically significant difference. The closest approach of humpbacks averaged 3000m with guns off and 2700m with guns on, with sperm whale results virtually identical; dolphins, by contrast, came much closer during guns-off, 209m, than when guns were on, 1080m. Read the rest of this entry »

Agardy, Aguilar, Canadas, Engel, Frantzis, Hatch, Hoyt, Kashner, LaBrecque, Martin, Notarbartolo di Sciara, Pavan, Servidio, Smith, Want, Weilgart, Wintle, Wright. 2007. A global Scientific Workshop on Spatio-Temporal Management of Noise. Report of the Scientific Workshop. 44 pages. [DOWNLOAD(pdf)]

AEI Lay Summary
In June 2007, a workshop was held in the Canary Islands to consider the potentials for extending the management principles used in Marine Protected Areas to provide some protection from anthropogenic noise. Fundamental to the purpose and effectiveness of MPAs are “spatio-temporal restrictions” (STRs) of specific human activities: for example, excluding fishing, from a specific area (spatial restriction), or sometimes at times of special biological importance, such as spawning (temporal restriction). Few of today’s MPAs are large enough to provide protection from “elevated levels of ensonification:” buffers of tens of kilometers would be necessary for protection from mid-frequency sound, and a hundred or more kilometers from low-frequency sound. Read the rest of this entry »

Stellwagen Sanctuary Noise Monitoring to be Model for “Sound Budget” Research Worldwide - The hydrophone array deployed in Stellwagen Bank is far more than a ship-strike warning system; it is the first large field test of what many bioacousticians have been long calling for: a global network of monitoring systems that will dramatically increase our understanding of the distribution of human noise in the world’s oceans, and the ways local animals respond. NOAA researcher Sofie Van Parijs says the Sanctuary is a perfect place to build a case study that can provide a benchmark  Read the rest of this entry »

Listening Buoys Deployed in Shipping Lanes Near Boston - Ten hydrohones installed in December in and near Stellwagen Bank National Marine Sanctuary are now active, monitoring the busy shipping lanes for whales. When a whale is heard, tanker captains are notified within a half hour, and required to slow down (which reduces noise) and post lookouts, so that fewer extremely endangered Northern right whales are killed by ship strikes. The listening network will also help scientists to understand how the whales respond to the approach of ships. “A lot of the coastline throughout the world is becoming industrialized,” said Sofie Van Parijs,  Read the rest of this entry »

Urban Noise Threatens Dawn Chorus and Bird Populations - European researchers are increasingly concerned about accumulating evidence that urban and suburban noise is having dramatic effects on bird populations. Some birds may be adapting by developing new behaviors, perhaps changing dramatically enough to be considered new species: nightengales sing up to 14dB more loudly in the city (some at 95dB, enough to cause discomfort to human ears), great tits are singing at a higher pitch, and robins have abandoned their noisy dawn (i.e. rush hour) chorus and now sing at night, when it is quieter. Birds must hear each other in order to mate and warn each other of predators. Declining populations of house sparrows (down by two-thirds over the past couple of decades) and overall bird populations (down 20% in the past four years) could be due to difficulty in finding mates, or abandonment of urban and suburban habitat.Source: Daily Mail, 3/26/08 [READ ARTICLE]

Digital downloads of favorite Pulse of the Planet programs - Pulse of the Planet, the long-running 2-minute public radio feature, is now offering large collections of mp3 versions of shows, grouped in popular themes. The first three sets (23-49 shoes each, priced at $5-9) focus on hurricanes and tornadoes, whales, and global warming.  [WEBPAGE]

Toothed Whale Hearing Senstivities Can Be Turned Up and Down
Supin, Nachtigall, Breese. Hearing sensitivity during target presence and absene while a whale echolocates. J. Acoust. Soc. Am. 123 (1), January 2008, 534-541
This very interesting paper, digging deeper into a topic that had emerged in previous studies of toothed whale hearing, reveals that a pilot whale could apparently “turn up” its hearing sensitivity, so that it could listen for fainter (more distant) sounds when echolocation clicks did not reveal nearby echoes. The research used a captive whale, outfitted with suction-mounted EEG electrodes to measure evoked potentials as it echolocated; half the time, a target fish was nearby, and half the time there was no nearby fish. When no fish was present, hearing sensitivity was 20dB higher (ie it could hear sounds 20dB more faint).