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New research listening in on whales as they hunt

Bioacoustics, Effects of Noise on Wildlife, Human impacts, Ocean, Science, Seismic Surveys, shipping Comments Off

Two new research projects are taking important next steps in understanding the importance of sound, and clear listening, to whales.  In recent years, ocean bioacousticians have introduced the concept of “communication space” or “effective listening area” to scientific parlance. This began as a conceptual framework for thinking about how human sounds (especially shipping noise) may reduce the area across which whales can hear and be heard; researchers are now digging into more of the details of how this may actually impact animals in their daily lives.  After several recent studies that focused on whales hearing each other (and so framing their results in terms of “communication space”), two new studies are gathering initial data that may inform considerations of the ways whales listen for the presence of prey.  While whales can, and do, change some of their communication signals or patterns in order to be better heard by other whales in noisy conditions, there’s no such compensation that can help a whale hear their prey through a wash of noise.

Both of the new studies are taking advantage of acoustic tags to allow scientists to listen in on whales as they are foraging.  These tags are about the size of a large cell phone, and are attached to the animals with suction cups; they remain attached for up to 16 hours, then float to the surface for retrieval.  While attached, they record all sounds the whales hear and make, as well as logging swimming speed and dive orientation.

Orca attack seal near shoreWEBOne study is further along, having just published its first results, which confirm that orcas can hunt in near-total darkness, apparently relying only on zeroing in on their prey (in this case, seals) by listening for their mating calls.  These orcas do not use echolocation while hunting (other orcas, hunting salmon, do echolocate); they hunt in stealth mode, then dispatch their victims with a swat of their tail flukes.  This initial evidence is not totally conclusive; followup studies will confirm that orcas do, indeed, seek out seal sounds.  And, this sort of study is but the first step toward quantifying the extent to which ocean noise may limit the range over which orcas can hear seals while hunting.

The second study will begin next year, and will be putting the acoustic tags on large whales, to see whether they’re using acoustic cues to help locate aggregations of fish.  According to Dr. Rochelle Constantine:

“Acoustics within the marine space are really important for many organisms, yet we don’t know a lot about how it drives organisms’ interaction with their environment. We’re interested in looking at how the larger animals use the acoustic environment, particularly for food, and testing the hypothesis that food patches have specific sound signatures.”

Lunging Brydes Wha 300WEBShe said the sound of “bait balls” of prey, such as schools of fish, could be greatly heightened when a feeding frenzy involving larger fish and seabirds broke out.  Dr Constantine said whales had been observed swimming rapidly from over a kilometre away toward prey aggregations, “so we’re very interested to find out if there are specific acoustic cues they home in on”.

This study plans to play recorded sounds of fish aggregations and other prey sounds while the tags on the whales.  (I suppose if they happen to get lucky and have an actual feeding event occur while tags are attached, that will be a bonus, but the playback will serve as a reliable testing condition.)  This team is also interested in using acoustic tags on large fish and sharks, to explore the ways they may rely on listening, as well.

Ocean noise may disrupt larval development

Effects of Noise on Wildlife, Ocean, Seismic Surveys Comments Off

AEI lay summary of:
Natasha Aguilar de Soto, Natali Delorme, John Atkins, Sunkita Howard, James Williams, Mark Johnson.  Anthropogenic noise causes body malformations and delays development in marine larvae.  Nature Scientific Reports, 3:2831.  DOI: 10.1038/srep02831 Download PDF

Just months after shipping noise was shown to cause dramatic behavioral changes in crabs, this new paper provides the first evidence that low-frequency seismic airgun sounds may trigger developmental delays and malformation in the larvae of shellfish.  Over the past decade or so, as researchers have looked more closely at behavioral disruptions caused by human noise sources, including temporary displacement of some fish stocks away from seismic surveys, there has been some concern that acute noise exposure from high-intensity sound sources such as airguns could also affect larval development.  If this were shown to be so, then regulators may need to consider protecting some vulnerable areas from intense noise exposure during seasons of key larval development.

This study exposed scallop larvae to recorded sounds of airgus, and compared larval development beginning after 24 hours of sound exposure and continuing until 90 hours.  This encompassed several stages of larval development, with 470-800 larvae examined at each sampling time.  

AirgunsLarvae350For the first day and a half, larvae exposed to airgun noise showed significant developmental delays.  At close to two days, the noise-exposed group appeared to be nearly as likely to be fully developed as the control group (upper right chart).  But, after passing the 48-hour mark, as the larvae moved into the next stage of development, those in noise lagged again; at 66 hours, all of the control larvae had completed the D-veligar development, while a large proportion of those exposed to noise did not complete this transition.  In addition, a significant proportion of the noise-exposed larvae began exhibiting physical abnormalities (localized bulges in the soft body of the larvae, but not in the shell).  By the end of the study, at 90 hours, an average of 46% of noise-exposed larvae showed malformations, ranging from 27%-91% in the four flasks being independently analyzed. (Ed. Note: I’ve reproduced five of the seven charts here, omitting samplings at 54hrs and 90hrs for the sake of better readability.)

The authors note that “the abnormalities observed here are comparable to those caused by chemical pollutants or water acidification, which have a clear impact on larval survival.”  They suggest several possible mechanisms for the abnormal bulges observed, and conclude that “although the exact mechanism is far from evident, physiological stress is likely the mediator for the developmental delays and growth abnormalities reported here.”  Further, the authors note that while behavioral responses vary widely both among and within species, stress response mechanisms are more generally similar across taxa, “suggesting that other invertebrates with similar growth patterns may be similarly affected.”

Of course, the nature of sound exposures in the ocean will be markedly different than those in this laboratory experiment, in which larvae were repeatedly exposed to a steady stream of 160dBrms impulses, once every three seconds for 24-90 hours.  In particular, the authors suggest that particle motion, rather than sound pressure, is the likely trigger for the effects, and acknowledge that several factors make it difficult to accurately predict the impact zone around an airgun in which particle motion would approach the 4-6mm/s RMS experienced by the sound-exposed larvae here.  In addition, the long periods of continuous exposure used in this testing procedure, while necessary in order to determine if there were indeed clear dose-response effects, may not be widely replicated in the wild.  Accordingly, the authors recommend that future research aim to establish the thresholds of exposure levels and durations that cause the effects seen here.

However, the authors stress that “given the strong disruption of larval development reported here, weaker but still significant effects can be expected at lower exposure levels and shorter exposure durations, especially if some ontogenetic stages such as the D-veliger prove to be particularly sensitive.”

Global industry council forms new ocean noise working group

News, Ocean energy, Science, Seismic Surveys, shipping Comments Off

The World Ocean Council, an “international, cross-sectoral alliance for private sector leadership and collaboration in Corporate Ocean Responsibility,” has launched a new initiative to address ocean noise issues.  Planned to complement the ongoing efforts of the oil and gas industry’s Sound and Marine Life program and the International Maritime Organization’s ocean noise policy work addressing shipping noise, the WOO’s Marine Sound Working Group will be especially helpful in raising awareness of ocean noise issues among ocean industries—including ocean mining and port construction—that have been less involved in the issue over the past decade or so of intensive study.  

In an interview after the initial meeting of the Marine Sound Working Group, co-chair Brandon Southall noted efforts to find alternatives or noise-masking techniques for some noisy activities in which the noise is a by-product, rather than a necessary component of the work; he also stressed ongoing efforts to better understand the widespread effects of chronic moderate noise, in contrast to researchers’ earlier focus on localized, acute effects of specific loud noise sources.  See the full 6-minute interview with Brandon here.

Biologically rich areas off limits while Gulf seismic EIS is conducted

Effects of Noise on Wildlife, News, Ocean, Ocean energy, Seismic Surveys Comments Off

Thirty months after environmental groups sued to force ongoing seismic survey programs in the Gulf of Mexico to be subject to more robust compliance with the Marine Mammal Protection Act and Endangered Species Act, a settlement announced this week requires full EIS’s to be completed within thirty months from now.  In the meantime, surveys will be kept out of three key biologically important areas, as well as from nearshore waters during the spring calving season of bottlenose dolphins.  In addition, the oil and gas industry committed to continue working on alternatives that may affect sea life less widely, particularly vibroseismic techniques that would vibrate the seafloor directly (similar to a technique widely used for onshore oil and gas exploration), rather than via loud explosive sounds from airguns.  

3D seismicWEBAnd, the Bureau of Ocean Energy and Management will develop new standards to assure that airgun surveys are not unnecessarily duplicative.  Dozens of surveys take place every year in the Gulf, with repeat surveys sometimes needed to assess reservoir depletion, and as new and improved imaging capabilities are developed; often, survey results are considered proprietary, especially prior to bidding on leases.

3D seismic imagery, above; airguns firing, below.

Airguns firingWEB“Today’s agreement is a landmark for marine mammal protection in the Gulf,” said Michael Jasny, director of NRDC’s Marine Mammal Protection Project. “For years this problem has languished, even as the threat posed by the industry’s widespread, disruptive activity has become clearer and clearer.”

Of particular concern are several populations of whales that are relatively few in number, and thus vulnerable to any disruption—in particular, the Gulf’s small population of sperm whales, whose nursery in Mississippi Canyon was ground zero for the spill. In 2009 an Interior Department study found that Gulf sperm whales subjected to even moderate amounts of airgun noise appeared to lose almost 20 percent of their foraging ability, which may help explain why the population hasn’t recovered from whaling.

International Association of Geophysical Contractors (IAGC) President Chip Gill stated, “Under the settlement agreement, permitting of seismic surveys in the Eastern Gulf of Mexico will continue. (The exclusion zones) are all areas where no lease sales are scheduled and where the prospective areas have recently been surveyed using modern surveying technology. . . . Some of the mitigation measures in the settlement agreement are voluntarily employed by industry around the world. Many of the others have been employed by industry in the GOM for the last several years.”

One of the new requirements that may not have been widely used in the Gulf is the employment of listening devices to help identify whales that may be nearby but unseen by observers scanning for surfacing whales.  As with the controversy over Navy noise-making, much of the nitty gritty of the new EIS process will focus on subtle behavioral impacts, and the difficult question of how much such disruption is tolerable while maintaining the health of animal populations.  A recent scoping hearing in Florida, marking the beginning of the long EIS development process in one zone of the Gulf, included some back and forth on this question.

For a full list of the settlement requirements, see this CBD press release.
Previous AEI coverage here and here.

RELATED: Australian environmentalists are upset about seismic surveys OK’d in an area important to blue whales.  According to an article in The Standard, “Government guidelines are clear that seismic surveys should avoid places and time of year when whales are highly likely to be present,” said Michael Collis of the International Fund for Animal Welfare. “We can’t think of a clearer example of this than Australia’s largest ever sighting of blue whales. People should view noise pollution the same way they view chemical pollution. The scientific community is slowly waking up to what a problem this is.” Collis said the fear was the giant mammals could be displaced from their feeding grounds, causing unknown repercussions, and knocked back suggestions that environmentalists opposed all off-shore gas mining exploration. “In Australia there are over 300 oil and gas reserves. We are talking about five areas that are special to whales,” Mr Collis said.

 

WHOI researchers distill whale calls from seismic survey data

Bioacoustics, Effects of Noise on Wildlife, Ocean, Science, Seismic Surveys Comments Off

Researchers at Woods Hole Oceanographic Institution (WHOI) have completed a proof of concept study that appears to be able to identify individual whale calls in the data collected by seismic surveys.  In the initial data, the researchers were able to cull fin whale calls from the recordings made as airguns blasted their pulses of sound into the ocean floor.  Blue whales are also likely candidates for being heard on the recordings, since their calls also overlap with the frequencies of interest to seismic mapping efforts.

“We have a huge amount of data that can say, ‘Did they change their behavior? Did they stop feeding? Did they stop talking? Did they talk louder?’, and that’s what we want to know,” said WHOI seismologist Dan Lizarralde.

Lizarralde and collaborators are currently seeking funding to develop a computer algorithm that can help with the daunting task of extracting the whale calls from massive amounts of seismic survey data.

For the full story, including spectrograms and comments from other researchers, see this story on LiveScience.com

Mediterranean fin whales displaced by oil and gas noise

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Ongoing acoustic research in the Mediterranean has confirmed earlier indications that fin whales are far more affected by oil and gas exploration noise than has long been assumed. Manuel Castellote’s most recent paper details a set of disturbing findings, here summarized by the website Science Codex:

Maritime traffic and geophysical exploration –including the search for hydrocarbons– “drastically” reduces the song effectiveness –linked to reproduction and which propagates hundreds of kilometres beneath the Sea– of the whales, which are also the group of marine mammals with the greatest acoustic sensitivity at low frequencies. “The noise generated through human activity in the oceans leads to possible chronic effects on the health of this species”, Castellote states.

After analysing 20,547 hours of recordings of the sounds emitted by the whales, the study published in Biological Conservation indicated that the whales modified the characteristics of their songs in order to try to reduce the impact of noise on their propagation. In addition the researchers recorded a massive displacement of fin whales, triggered by the noise from geophysical prospecting at a distance of 285 km from the study area. “These recurrent displacements, together with the changes in acoustic behaviour, could increase the energy expenditure and reduce the reproductive success of whales affected by the noise”, the expert indicated.

In the long-term the consequences for these mammals are clear: chronic effects which impact on their survival emerge. “Noise in the marine medium, despite being recognised as a significant pollutant, is far from being controlled and regulated within the waters of the Exclusive Economic Zone of Spain”, warns Castellote

Offsore oil development expanding in remote Arctic seas

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The Anchorage Daily News ran a  great, detailed piece on the expansion of offshore oil and gas development in the Beaufort and Chukchi Seas north and west of Alaska.  It’s well worth reading in full.  The nut of the story is that Shell Oil, which has conducted seismic surveys in the northerns seas for the past few years, is gearing up to drill their first new exploratory well in over a decade.  If they find the oil they expect to, further seismic exploration and drilling is likely to follow in these remote waters, home to many species of whales.  Bowhead whales are especially sensitive to noise, especially cow-calf pairs, and have been found to give seismic surveys a wide berth.

Oil companies have been doing extensive research into the seasonal distributions of whales (especially belugas and bowheads), and have agreed to suspend operations in late August to accommodate the Alaskan natives traditional bowhead hunting season.  Meanwhile, Chris Clark, the Bioacoustics Research Program director at Cornell says, ”There are unanswered science questions.  It’s not clear what happens if a whale hears 1,000 of the explosions from air guns, or where it will go if an area is saturated with the sound. In addition, scientists are only beginning to study the effects of the sound on fish and other animals that make up the whole ecosystem.”

Go read the whole article!

Cook Inlet seismic survey permits challenged in court

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Permits issued by National Marine Fisheries Service to allow seismic surveys in Alaska’s Cook Inlet have been challenged in Federal Court.  Cook Inlet is home to a dwindling population of beluga whales (under 300), and the permits allow behavioral harassment of up to 30 belugas per year. In part, the challenge contends that this likely underestimates the impact, as, ”NMFS based its analysis on an unrevised, outdated, 15-year-old assumption about take levels that some of the world’s leading bioacousticians recently urged NMFS to discard – and that ignores the only existing study of airguns and belugas, showing impacts at far greater distances than NMFS has predicted here.” Saying that the Marine Mammal Commission recommended against issuing the permits, the suit claims that NMFS erred in its finding of “no significant impact.”

BelugaIn addition to three environmental organizations, the Native Village of Chickaloon is party to the lawsuit, saying that NMFS did not fulfill necessary consultation with the tribe, and noting that while the tribe is barred from its traditional hunts due to declining beluga numbers, the permits allow oil and gas development to put whales at risk.

The suit claims that an Environmental Impact Statement should have been prepared, rather than a less comprehensive Environmental Assessment.  As covered in previous AEInews posts over the past four years, NMFS has declared parts of Cook Inlet to be essential habitat for the belugas, though the 180-mile long inlet continues to bear the brunt of substantial industrial activity, including the Port of Anchorage and ongoing oil and gas development.

US east coast seismic survey EIS draft released

Effects of Noise on Wildlife, News, Ocean, Seismic Surveys 1 Comment »

The US Bureau of Ocean Energy and Management (BOEM) has released the Draft Programmatic Environmental Impact Statement that is the first step toward oil and gas development off the east coast.  The PEIS assesses the impacts of geological and geophysical (G&G) activities, primarily seismic surveys and test wells.

OCS seismicI’ve yet to dig into the PEIS to examine its alternatives or proposed mitigation measures, but a quick look at maps illustrating applications already received from oil and gas exploration companies affirms that the entire east coast could become an active seismic survey zone (the map at left is one of nine applications; there is much overlap among them).

UPDATE, 3/30/12: While those maps look impressive, both the International Association of Geophysical Contractors and the American Petroleum Institute have issued statements that surveys are unlikely to take place until the path opens for actual leases to be issued; the decision was already made to not issue any Atlantic leases during the current 2012-2017 planning period.  The applications for surveys currently on file were submitted during a period in 2008 when a long-standing Presidential order excluding oil and gas development on the Atlantic coast was lifted. ”Without an Atlantic coast lease sale in their five-year plan, theadministration’s wishful thinking on seismic research has no ultimate purpose,” said Erik Milito, upstream director at API. Chip Gill, IAGC President, stressed that “contrary to the statements [by US Interior Sec. Ken Salazar and BOEM Director Tommy P. Beaudreau], we do not expect seismic surveys to be conducted for years, and thus we don’t expect it to be available to help the federal government evaluate the resource base anytime soon.”

(and now back to our original post):
While very few animals are killed or injured by air gun sounds, behavior can be affected for tens of miles, and airgun sound can be heard (and so drown out some distant communication) for hundreds of miles.  I just returned from a BOEM workshop on the effects of ocean noise on fishes and invertebrates, where scientists shared research on reduced fish catch rates near surveys (the fish move away for a few days or weeks, then gradually return), and attempted to come up with a shared understanding of how to investigate whether ocean noise can affect fish communication, larval or egg development, or other aspects of ocean ecology (so far, there is little direct evidence of impacts, but some concern remains about masking of sounds fish use for many purposes, and the possible negative stress impacts of chronic noise exposure).

From looking at the maps of existing applications to do surveys (download pdf of rough maps of all 9 applications), it’s immediately apparent that BOEM could work to minimize duplicating of efforts by several companies.  It may be that there will be areas that are clearly inappropriate for oil and gas development (eg, key fishing grounds or other biologically important areas), or seasonal exclusions to reduce impacts on spawning or migration.

Of course, there’s also the bigger-picture climate change question of whether we really want to be continuing to pull more oil and gas from the ocean in the years after 2020 anyway; any new leases will be issued after 2017, with development following years later.  Meanwhile, BOEM is working hard to lay the groundwork for renewable energy development in offshore waters, targeting areas for wind, tidal, and wave energy systems.  For now, continuing to plan for oil and gas development is part of the Obama administration’s “all of the above” approach to meeting America’s future energy needs.

For more on the Draft PEIS, see BOEM’s PEIS website, which includes links to download the documents and submit comments, this press release from the Department of the Interior, and this blog post from NRDC (which stresses that quieter alternative technologies for oil and gas exploration are expected to be commercially available in 3-5 years).

Ocean noise assessment needs to look past dB, to context of exposure

Bioacoustics, Effects of Noise on Wildlife, Ocean, Science, Seismic Surveys, shipping, Sonar Comments Off

A paper recently published in Conservation Biology suggests that current ocean noise regulations are likely not providing sufficient protections against impacts on marine life.  The authors note that current regulations are based on preventing direct physical injury from very close exposure to sound, while considering behavioral impacts to decrease consistently with greater distance, or the “zones of influence” approach to noise impact assessment.  However, some key impacts, such as interruptions in feeding or temporary abandonment of important habitat, are not accounted for.

Rather than fully summarizing the paper here, I’ll turn you over once again to Caitlin Kight of Anthropysis, who has recently been providing excellent coverage of anthropogenic noise issues as part of her larger focus on human impacts in the natural world.  Please see her full post to get the whole story; here’s a teaser:

In a previous study on behavioral responses of marine animals to noise, one of the authors of the current paper found that the “zones-of-influence approach did not reliably predict animal responses.” Furthermore, we know from terrestrial studies that a variety of additional factors–an animal’s past experience and conditioning, current behavioral state, acoustic environment, and type of exposure, to name a few–all affect the extent to which it will be impacted by noise pollution.

…(Studies in terrestrial and ocean environments have shown that) noise can have more subtle, but equally important, effects on wildlife. For instance, abundance and diversity may shift as animals flee from, or learn to avoid, particularly noisy areas; individuals may alter their behaviors in counterproductive or even dangerous ways; and noise may make important acoustic signals difficult to hear, even in the absence of actual deafness. In short, the researchers write, the current marine noise concept “ignores a diverse suite of environmental, biological, and operation factors” that can impact both perception of, and response to, anthropogenic noise. Thus, they argue, it is necessary to overhaul the system and “[incorporate] context into behavioral-response assessment.”

Ellison, W.T., Southall, B.L., Clark, C.W., and Frankel, A.S. 2012. A new context-based approach to assess marine mammal behavioral responses to anthropogenic sounds. Conservation Biology, online advance publication.

Leading scientists call for reducing ocean noise

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NOAA humpback with calf copyTwo of the US’s most widely-respected ocean bioacousticians have called for a concerted research and public policy initiative to reduce ocean noise.  Christopher Clark, senior scientist and director of Cornell’s Bioacoustics Research Program, and Brandon Southall, former director of NOAA’s Ocean Acoustics Program, recently published an opinion piece on CNN that is well worth reading in full.  They stress the emerging scientific awareness that chronic moderate noise from shipping and oil and gas exploration is a more widespread threat to marine life than the rare injuries caused by loud sound sources like sonar.  Here are a couple of teasers:

Today, in much of the Northern Hemisphere, commercial shipping clouds the marine acoustic environment with fog banks of noise, and the near continuous pounding of seismic airguns in search of fossil fuels beneath the seafloor thunder throughout the waters. In the ocean’s very quietest moments, blue whales singing off the Grand Banks of Canada can sometimes be heard more than 1,500 miles away off the coast of Puerto Rico. But on most days, that distance is a mere 50 to 100 miles.

Whales, dolphins and seals use sounds to communicate, navigate, find food and detect predators. The rising level of cumulative noise from energy exploration, offshore development and commercial shipping is a constant disruption on their social networks. For life in today’s ocean, the basic activities that we depend on for our lives on land are being eroded by the increasing amount of human noise beneath the waves.

These stark realities are worrying. But emerging technologies for quantifying and visualizing the effects of noise pollution can help drive a paradigm shift in how we perceive, monitor, manage and mitigate human sounds in the ocean. Ocean noise is a global problem, but the U.S. should step up and lead the way.

Clark and Southall make three specific recommendations: to establish a more comprehensive network of acoustic monitoring stations in order to better understand our overall acoustic footprint in the seas; to encourage and accelerate development of noise-reduction technologies (especially to make ships quieter, and also to develop new technologies for oil and gas exploration and underwater construction that generate less noise); and a shift in federal regulations from avoiding acute injury, toward protecting ocean acoustic habitats and ecosystems.

Oil drilling begins in Cook Inlet, near beluga critical habitat

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Beluga noaa

A drilling rig is up and running in Cook Inlet, along the southern Alaska coast.  The rig, which will remain in the Inlet for 8 or more years, drilling numerous wells during the short summer seasons, expects to complete this first oil and gas well by the end of October, well before ice develops.  Local environmental groups pressed the Army Corps of Engineers and NOAA to not allow the rig into the inlet, citing concerns that oil and gas development activity will negatively impact a recently-designated 3000-square mile critical habitat for the critically endangered local beluga whale population.  In addition to possible impacts of a spill, noise from drilling in a central concern.  The permits allowing drilling require the company to maintain beluga observation crews, and to reduce the speed (and thus noise) of the drill when belugas are nearby, and shut down operations if they come very close.

Chabitat cibelugas1209 sm

Cook Inlet is over a hundred miles long, with Anchorage at its inner end; this is also the section of the Inlet that is now designated as critical habitat.  The first drilling operation is in the central part of the critical habitat, between Kenai and Tyonek on the map below.For more on the situation, see the two links above, which go to fairly detailed articles in the local media, and see these two previous AEI posts about the Cook Inlet belugas.

Feds to assess Gulf seismic surveys for MMPA compliance

Ocean, Science, Seismic Surveys 1 Comment »

Ongoing pressure from environmental groups has spurred the National Marine Fisheries Service to take a closer look at the effects of seismic surveys on whales in the Gulf of Mexico.  The Obama administration has announced that NMFS will prepare a Letter of Authorization, which will look more closely at the question of whether current seismic survey practices comply with the Marine Mammal Protection Act.  Up until now, Gulf oil exploration has only been monitored for effects on endangered species.

Meanwhile, the Department of Interior and a coalition of environmental groups are engaged in settlement talk in a separate lawsuit filed earlier this year, which challenged the first new exploration permits issued for the Gulf since the Deepwater Horizon accident.

These legal challenges resemble the successful challenges to Navy sonar training exercises, which also called on the government to do more complete environmental impact studies of practices which were widespread and had been going on with minimal oversight for decades.  While the Navy did complete the EIS’s, it’s worth noting that they have not led to major changes in how sonar training takes place; environmental assessments often lead to determinations of “negligible impacts” on wildlife, and it’s common that the most protective alternatives considered in an EIS or EA process is not the one chosen as the final outcome.   Read the rest of this entry »

Squid grievously injured by LF shipping, seismic noise?

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Squid beached copy

New research indicates that squid and their relatives are injured by exposure to low frequency noise similar to the “acoustic smog” created by widespread shipping and localized seismic surveys.  This is the first study to show physiological damage caused by noise in animals who do not have ears or hearing organs. The study exposed squid, cuttlefish, and octopuses to two hours of low frequency sound in a variety of frequencies from 40 to 400Hz; the fish were in a tank, and could not move away from the noise.  According to a report in New Scientist, the researchers “were astonished by extensive damage to the statocyst, a bulbous organ in the head of cephalopods that senses gravity and motion, enabling them to balance in the water and direct where and how fast they swim. Without this organ, cephalopods are practically powerless to move, are unable to hunt, and will become easy prey themselves.”  In 2001 and 2003, giant squid were found beached in an area where seismic surveys were taking place; though the injuries observed then could not be tied to acoustic trauma, the new research suggests that such damage can be caused by sound exposure.

The New Scientist article continues:

Post-mortems showed that the linings of statocysts from cephalopods not exposed to sound retained the fine hairs that sway as the animals move through water, and are essential to the animals’ balance and orientation. Statocysts from the exposed animals, by contrast, had lost huge patches of hair, leaving holes in the membranes of the organ’s cells. The insides of the cells had pushed their way through the holes, and mitochondria – the power plants of cells – had suffered extensive damage. By killing and examining the animals at intervals up to four days after the single sound exposure, the team showed that the damage got worse with time, long after the sound had been turned off.

The sounds used in the study were of moderate intensity: SPLs of 157dB re 1uPa, with peaks at 175dB, roughly equivalent to the sound of a large ship at 100 yards or a seismic survey at 500-1000 yards. (By comparison, injury is not presumed to take place in marine mammals unless sound is 180-210db). Similar studies in fish, using caged animals, have sometimes found similar hair damage to hearing organs, but only at much higher sound levles, and, in many cases even high levels of sound did not cause such injury.

Michel André, lead researcher, notes in a statement that ”If the relatively low intensity, short exposure used in our study can cause such severe acoustic trauma, then the impact of continuous, high intensity noise pollution in the oceans could be considerable…This is the first study indicating a severe impact on invertebrates, an extended group of marine species that are not known to rely on sound for living. It left us with several questions: Is noise pollution capable of impacting the entire web of ocean life? What other effects is noise having on marine life, beyond damage to auditory reception systems? And just how widespread and invasive is sound pollution in the marine environment?”

UPDATE, 4/15: While this study has been widely praised as an important step in understanding possible noise impacts on a new family of ocean creatures, there are some caveats being put forward as well.  Michael Stocker of Ocean Conservation Research notes in a letter to his network that it is as yet unclear whether the impacts are more related to “particle motion” or “pressure gradient” aspects of acoustical energy, so “it could be that the closeness of the lab signals may have different impacts than equally loud exposures generated from further distances.”  T. Aran Mooney, who agrees it’s a “good first step,” suggests that more information is needed about how the noise exposure was measured.  And of course, these results will need to be replicated and expanded upon, as always.

NOTE: Apologies for my boring post title.  I thought it was pretty decent – clear, explanatory – until this one showed up in by Google News ocean noise feed, covering the same story: “Ocean Noise Pollution Blowing Holes in Squids’ Heads.” I bow before the page-click-attracting Master over at Discovery News…

Oil industry seismic survey studies: ramp up and long-term population trends

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Two new studies on seismic survey impacts have been released by the Joint Industry Program (JIP) Sound and Marine Life research program, funded by oil and gas companies.

The first looked at the effectiveness of “soft start” ramp up of seismic survey airguns at night and at times of poor visibility.  This has become standard procedure, but there have been some concerns that if marine mammals were very close to the ship, even the low sound levels at the start of the ramp up could be loud enough to cause hearing damage.  Based on two different modeling approaches, the study found “no instances…in which the threshold levels for hearing injury for cetaceans were reached during the initial stages of the soft-start sequence. This suggests that the animals are not at significantly greater risk of harm when a soft start is initiated in low visibility conditions.”  Link to pdf of report at the website of the International Association of OIl and Gas Producers.

The second study aimed to address “the rarely-charted relationship between oil Exploration and Production (E&P) activities and trends in cetacean stocks.”  The study cites case studies involving populations of sperm whales in the Gulf of Mexico, humpback whales, blue whales and fin whales off the coast of California, northern bottlenose whales off Nova Scotia and harbour porpoises and minke whales off the east coast of the UK. The study, published in Aquatic Mammals,  provided new insights into the worldwide distribution of E&P activity in relation to marine mammal populations and has also revealed striking data gaps in our understanding of cetacean population numbers and trends. While the report’s review of seven stocks “found signs of an increase in numbers in one population (Californian humpback whales),” for the remaining six, “population trends could not be assessed due to the high variability in the abundance estimates.”  Link to pdf of this report.

In essence, there is not enough data to really tell us whether ongoing oil and gas activity has reduced stocks over the long term.  As usual in the many cases where ocean noise and population studies come up against this paucity of solid data, the researchers recommend that someone should fund of future studies ‘that provide more comprehensive data on cetacean stocks.”

JIP research page
Main JIP website

OGP publications page
OGP main page

First-ever lawsuit challenges Gulf of Mexico oil, gas development

Effects of Noise on Wildlife, News, Ocean, Seismic Surveys Comments Off

For the first time, decades of oil and gas development in the Gulf of Mexico is being challenged in court, on the grounds that the noise of seismic surveys used to pinpoint oil reservoirs has a negative impact on the region’s endangered sperm whales.  A consortium of environmental groups, including the NRDC, CBD, and Sierra Club filed a formal notice of intent to sue, because 10 new oil exploration and development project have been approved in recent months without obtaining permits required by the Marine Mammal Protection Act and Endangered Species Act. “Seismic surveys have a vast environmental footprint, disrupting feeding and breeding of wildlife over great distances,” said Michael Jasny, a senior policy analyst at NRDC. “It is intolerable to think that the same species threatened by the Gulf spill will have to contend with the industry’s constant pounding, without any serious attempt to mitigate the harm.”

This legal challenge is similar to those mounted against Navy mid-frequency active sonar training, in that they are designed to assure that the behavioral impacts of seismic survey noise are considered, and that Incidental Harassment Authorizations are issued, with conditions meant to avoid any injury of animals, and minimize behavioral changes. The MMPA and ESA clearly require careful assessment and permitting of any activity that may negatively affect marine mammals or endangered species.

What is unclear, though, is how (if at all) oil and gas exploration activities might change after going through these proper legal challenges.  The US Navy now prepares full Environmental Impact Statements for all of its active sonar training areas, and receive IHAs from NOAA, but this legal compliance has not reduced their training activities or succeeded in putting any biologically rich areas off limits–in effect, NOAA has issued the permits after long official assessments that the activities have no significant impacts.  LIkewise, the oil and gas industry does have procedures in place to reduce sound output when animals are (very) close, and research into the behavioral effects of noise exposure at greater distances (lower sound levels) is ambiguous, though concerning.  See this earlier post about AEI’s work in this area, assessing research about behavioral impacts of moderate noise, including seismic.

The rhetoric from the litigants is surprisingly personal, implying that Gulf of Mexico exploration activity is being ramped up by this administration.  “Under Salazar’s watch, the Department of the Interior has treated the Gulf of Mexico as a sacrifice zone where laws are disregarded and wildlife protection takes a backseat to oil-company profits,” said Miyoko Sakashita, oceans director at the Center for Biological Diversity.  (See press release) What is unstated, and may in fact be more to the point, is that the Gulf has been a sacrifice zone for decades.  The fact is that these animal populations in this truly industrialized sea have been living with seismic exploration, drilling, and lots of ship traffic for many many years; some populations, including sperm whales, appear stable. While some may suggest this reinforces NOAA’s current stance that the activities do not cause any significant impact on wildlife, and others (including AEI) say it’s clearly long past time to consider the cumulative and long-term impacts of this activity on marine life, the villain is not Ken Salazar.  It’s our continuing addiction to oil, pushing us to search in ever deeper and more hazardous waters to fill our boundless needs.

Squid can hear! And why it may matter…

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A month or so ago, new research by Aran Moody at Woods Hole was published and garnered a bit of press attention — perhaps largely because it involved squid, whose public fan base rivals that of their more “charismatic” brethren, the whales and dolphins.  I’ve been meaning to post about it, but didn’t get to it.

Just as well, because today, Canada’s MacLean’s magazine blogs the story just right, offering the best mix of science and why it matters that I’ve seen.  The key points are that squid appear more sensitive to low-frequency sounds or pressure waves (such as that perhaps preceding the approach of a whale, rather than the echolocation clicks of dolphins), and this could mean that shipping or seismic surveys may displace squid.  There’s also a chance that invasive squid species, such as the Humboldt squid decimating fisheries along the northeast Pacific coast, could be chased away with noise (oh, joy!).  Check out the full post at MacLeans here.

Scientists to place 76 listening devices in Moray Firth to assess impacts of oil/gas and wind developments on wildlife

Science, Seismic Surveys, Wind turbines 1 Comment »

An impressive array of 76 acoustic monitoring buoys is planned to be deployed in Scotland’s Moray Firth this summer, to listen in on local populations of dolphins, porpoises, whales, and seals.  Scientists from Aberdeen University will place the recording devices up to 70 miles offshore, expanding on work carried out last summer on a smaller scale.  Dr. Paul Thompson, one of the lead researchers, explains: “This will help us get a better understanding of the distribution of particular species. We will be looking at the impact primarily of oil and gas exploration, but also the development of wind farms. During construction phase of these developments, it can be quite noisy and affect marine mammals. It will allow us to get a better understanding of how they use different parts of the Moray Firth and to understand what parts are most important” to each species.  Read more at The Scotsman.

Lawsuit to target oil and gas noise in Gulf of Mexico

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The Center for Biological Diversity has filed a 60-day notice of intent to sue the Department of Interior, claiming that the Minerals Management Service (MMS) has been approving oil and gas exploration and development for years without making the companies obtain the “incidental harassment permits” required by the Marine Mammal Protection Act and Endangered Species Act.  While the CBD’s press release focuses on the 100 seismic surveys and 300 drilling operations approved since the Obama administration came into office (and uses some pretty inflammatory language aimed at Secretary of Interior Ken Salazar), the Gulf has been one of the world’s most industrialized ocean regions for many decades, and the practices described are long-standing.  According to the CBD press release, the primary impact that has not been addressed is the effects of industry noise on whales and other sea life; CBD point out that some of the sounds are loud enough to damage whale hearing (though fails to note that this occurs only at very close range) as well as disrupt important behaviors (which can occur many miles away). The North Sea is the only other ocean region that’s been so widely impacted for so long by oil and gas development, with West Africa, Brazil, Indonesia, and the South China Sea all working hard to join the party in recent years.

The CBD stresses that the many oil and gas activities in the Gulf must be more thoroughly examined, especially since in some conditions noise can reverberate and become nearly continuous.  While the National Marine Fisheries Service was consulted by the MMS, with NMFS issuing a Biological Opinion that included the assessment that whales would be affected, no harassment  or  permits were issued or required by MMS. (Ed. note: I haven’t read the Biological Opinion, but there’s a good chance that NMFS considered the effects to be negligible; this is a common bottom line in agency consideration of noise impacts, and is the grounds used to issue the harassment permits.  It is likely that while CBD’s suit is based on the procedural question of missing permits, the root of their challenge is a disagreement that the effects are negligible.) The notice of intent concludes by saying: ”An appropriate remedy that would prevent litigation would be for the Secretary to initiate the process to authorize the take of marine mammals in the Gulf of Mexico pursuant to Section 101(a)(5) of the MMPA by a date certain. Meanwhile, the Secretary must stop approving lease sales, exploration and development plans, and seismic exploration permits in the Gulf of Mexico until and unless it obtains the required authorizations under the MMPA and ESA.”

UPDATE: According to a Reuters report, the Interior Department and the White House Council on Environmental Quality (CEQ) announced on Friday the 15th that they would initiate a review of MMS’s NEPA procedures, especially their obligations under the MMPA and ESA.  Earlier in the week, Secretary Salazar had announced a plan to split the MMS into two parts, one of which would collect royalties, with the other overseeing regulatory enforcement.

Acoustic Zoom promises to provide high-resolution images of offshore oil and gas reserves

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A small item in the Marine Technology Reporter just clued me in to what looks to be an interesting new line of acoustic imaging products that could have potential to augment, or perhaps reduce the need for, repeated seismic surveys of active oil and gas fields. PanGeo Subsea has announced new financing to develop their Acoustic Zoom, which they compare to a “deep earth telescope” capable of providing detailed imagery of subsea geology down to 6000m below the sea bed.  Current information does not clarify any details about the products’ acoustic output.

Most companies now utilize repeated seismic surveys in order to track the depletion of offshore oil fields; doing repeated 3D seismic surveys over time is termed “4D” surveying.   According to a recent PanGeo press release and backgrounder, one of the major limitations of current marine 4D surveys is that the resolution at reservoir depths is often too coarse to be able to focus the seismic attributes to a specific compartment or feature of the reservoir. Their Acoustic Zoom is pitched as a novel high resolution method which uses steered beams on reception and on transmission to produce images with higher definition than can be attained with conventional seismic techniques. They project that it will “reduce the cost, scheduling and logistics involved with 4D seismic imaging, including reductions in the amount of equipment, data acquisition time, as well as the time to compute and interpret seismic results. We expect our technology to become an important tool for permanent reservoir monitoring applications.”  To , read more about the Acoustic Zoom, see the these two press releases, announcing private funding received in July, and Canadian government funds received in February.

PanGeo Acoustic Corer: the arms turn to image a full circle below

PanGeo Acoustic Corer: the arms turn to image a full circle below

There is no information on the company’s website about the source levels or frequencies of the acoustic pulses used by any of their innovative systems.  In addition to the Acoustic Zoom, which is still under development, PanGeo has previously brought to market two related products, the Acoustic Corer and the Sub-Bottom Imager.  The Acoustic Corer provides high-resolution images that can be manipulated in great detail; each scan covers an area 14m in diameter and 30-80m deep.  See this page for three videos of the Acoustic Corer and its data.  The Sub-Bottom Imager is an ROV that moves along the seabottom, making images 5m wide and 5m deep.  Both of these products are more oriented toward pre-construction surveys to help avoid surprises as infrastructure is being placed on or into the seafloor.

AEI annual report, Ocean Noise 2009 is now available

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The Acoustic Ecology Institute has published Ocean Noise 2009, the fourth in its annual series of reports reviewing new research and regulatory developments in ocean noise. AEI’s annual recaps are widely anticipated and circulated among ocean noise scientists and regulators, as well as within NGO and journalist communities.

The report can be viewed or downloaded as a 45-page PDF, or viewed in the SlideShare plug-in, below.

This year’s report includes coverage of two ongoing issues, seismic surveys and Naval active sonars, with particular focus on the Navy’s continuing roll-out of Environmental Impact Statements for its offshore training ranges and the targeting of Columbia University’s seismic research vessel by environmental activists.

This year’s report introduces a new feature that will be of special interest to journalists: AEI Resource Collections on two topics that will be central to ocean acoustics policy and research in the coming years.

More details below the fold Read the rest of this entry »

NOAA steps up, announces new active sonar oversight with possible off-limits areas

News, Ocean, Science, Seismic Surveys, Sonar 2 Comments »

NOAA Administrator Jane Lubchenco has announced a series of sweeping new initiatives designed to push the Navy forward in its efforts to understand and mitigate the impacts of mid-frequency active sonar on marine mammals.  In response to a request from the Council for Environmental Quality (CEQ), which asked NOAA to conduct a comprehensive review of this controversial issue, Lubchenco outlined several important new initiatives which mark a more active role for NOAA in moving both the science and policy efforts forward.  Previously, NOAA had worked closely with the Navy on its Environmental Impact Statements, but had largely rubber-stamped the resultant Navy mitigation plans, which consistently rejected any alternatives that set biologically important portions of US coastal zones off-limits to sonar training.

The new NOAA initiatives include four key elements, three of which dovetail closely with long-time concerns and requests from environmental organizations for NOAA to more actively protect areas of biological significance from both Navy and oil and gas noise, and three of which will help fill key data gaps identified by research scientists over the past decade.

  • First, NOAA will work with other civilian agencies (e.g., MMS) to reinitiate comprehensive aerial cetacean and sea turtle surveys, in order to establish more fine-scale population estimates, especially in Navy training ranges.  Currently, many Navy EISs rely on coarse, regional population estimates, leading to unrealistic estimations of population density being spread evenly across large areas.
  • Second, NOAA’s National Marine Fisheries Service will host a workshop aimed at developing a plan to create a comprehensive “ocean noise budget.”  This is a long-time desire of both researchers and environmentalists, and would identify areas in the ocean where human noise is relatively sparse, as well as areas in which new human activity would not add substantially to already high noise levels.
  • Third, another NMFS workshop will be organized to identify marine mammal “hot spots” of particular biological significance.  All three of these initiatives tie together nicely to bring acoustics into the Obama administration’s stated aim of moving toward more coherent Marine Spatial Planning, a sort of ocean zoning approach that would help guide human activities toward areas where they will have less impact on animals.  In a clear indication that NOAA may take a more proactive role in pushing the Navy to leave some areas out of its training zones, the letter stresses that “Protecting important marine mammal habitat is generally recognized to be the most effective mitigation measure currently available.”
  • Finally, NOAA has already begun taking an active role in ongoing meetings between the Navy and the National Resources Defense Council; these meetings were part of a legal settlement and are designed to resolve outstanding differences about Navy active sonar operational and mitigation measures.  Lubchenco notes that “NOAA’s participation will enhance these discussions and help resolve differing views….I also expect the Navy to be open to new ideas and approaches to mitigation that are supported by the best available science.”

Indeed, including “spatio-temporal restrictions” (areas or times when activity is prohibited) in active sonar permitting has been a major sticking point between the Navy and NRDC and other environmentalists, and is something the Navy has consistently and explicitly rejected in the first round of sonar EISs, which have been finalized over the past year for most of the key Navy ranges (California, Hawaii, East Coast and just this week, the Gulf of Mexico), none of which included any limits on where and when the Navy could do sonar training. “The Navy’s Southern California range is over 120,000 nautical miles in size — about the size of California itself,” NRDC’s Michael Jasny points out. “The Bush administration did not put a square mile of this vast area off limits to sonar.”

All in all, this is a remarkable and very productive first step for this administration as it enters the long-contentious waters of active sonar regulation, ocean noise in general.  You can download Lubchenco’s detailed letter at the NOAA website.

Bias in Military (or Conservation) Funded Ocean Noise Research

Ocean, Science, Seismic Surveys, Sonar Comments Off

(this item first appeared in AEI’s lay summaries of new research)

Wade, Whitehead, Weilgart. Conflict of interest in research on anthropogenic noise and marine mammals: Does funding bias conclusions? Marine Policy 34 (2010) 320-327.

In the United States, the US Navy funds about 70% of the research into the effects of ocean noise on wildlife (and half, worldwide). For many years, conservation groups have questioned whether this preponderance of funding is skewing research results, whether by constraining the types of questions being studied, or by leading researchers to downplay negative impacts of noise in order to continue receiving funding. The authors of this new study report a significant correlation between Navy funding and results reporting “no effect” of noise, based on their analysis of  several wide-ranging reviews of ocean noise science, and of the primary research papers cited in these reviews.  While the data behind their conclusion is clearly explained, the results don’t look nearly as clear-cut to me; I question the comparability of the five reviews used, and while the trends in primary papers is more obvious, it’s hard to ignore the fact that the majority of military-funded papers still found that noise had effects.  Indeed, as the authors make clear, it’s the conservation-funded reviews and primary research that is most clearly one-sided in its results (though there are good reasons for this, also fleshed out by the authors and in AEI’s commentary below).  In AEI’s view, studies like this – and indeed, reviews such as those considered here – are diligent exercises in quantifying an issue that has become, for all practical purposes, an exercise in divergent world views and beliefs talking at and past each other.

This post includes more analysis and interpretation by AEI than we generally include in our science summaries; it’s a long read, but the issues that triggered this study are important ones. Though the clear-cut results reported here are difficult to take at face value, it is well worth considering the underlying forces that drive tensions between environmental groups and Navy/industry actions in the seas.  While primary research and even literature reviews funded by the military don’t appear overly biased toward finding no effect (since in both cases, they include far more results showing effects than not), it remains that in practical terms, the EIS’s generated by the Navy and the mitigation measures imposed by regulators on both military and oil and gas activities are largely grounded in the belief – and regulatory determination – that any effects of these activities are “negligible,” to use the formal term. Thus the focus of the conservation community on funding research and publishing overviews that emphasize credible studies outlining observed negative effects is understandable.

Of special note is that the authors did not find any strong trend toward bias of results reported by independent, academic researchers receiving Navy funding for research studies – these studies showed a similar proportion of effect and no effect results as studies funded by neither the military nor conservation groups (though when comparing military-funded studies with all the others, including consevation-funded, a non-statisticially significant trend of 1.64 times more “no effect” findings was observed).  This should diffuse widespread concerns that cash-strapped academic researchers are “cooking the books” or avoiding publishing negative findings in order to retain Navy funding (though it is perhaps unsurprising to note that few if any key Navy-funded scientists are among the researchers who are willing to speak out publicly to push for stronger regulations on ocean noise). The authors conclude that “much of the bias in military-funded research was in work carried out at military institutions, rather than in studies funded by the military but carried out at universities and other institutions.”  Thus, research coming directly out of military offices is likely to remain less reliable as representing “the whole picture,” as may research entirely funded by conservation groups. Still, by integrating and considering the full range of studies reported in all of these reviews, the public can get a pretty decent picture of current state of our understanding of the effects of ocean noise.

Of note, though, is that the proportion of “no effect” to “effect” findings is slightly lower in military-funded studies. In addition, military-funded studies are three times as likely to report BOTH effects and lack of effects in a single paper; this could indicate either a more careful assessment of the margins where effects are just noticeable, or a tendency to split the difference in order to either underplay the effects or accentuate the non-effects to assuage funders.

While ocean noise issues came to public awareness after a series of stranding deaths and lawsuits, the fact is that deaths and injuries caused by noise are very rare.  Even the leading environmental activists have shifted their focus, and today nearly all of the controversy over military and oil and gas noise boils down to differing interpretations of how important moderate behavioral changes are, and whether they should be avoided or not. And science is nearly incapable of shedding any definitive light on how important behavioral changes are, thus leaving the two sides largely reliant on their divergent faith: the Navy and oil industry’s faith that the behavioral changes are transient and negligible, and environmentalists’ faith that chronic behavioral disruption by human noise is bound to have negative consequences. Meanwhile, ethical questions about humanity’s relationship to the natural world are outside the bounds of discussion on one side, and central to the whole discussion on the other.  This is not as black and white a picture as either side may paint, but it’s where we are.

For AEI’s full summary and discussion of this important new study, dive in below the fold…..

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MMS acoustic monitoring workshop includes AEI ocean noise report as key reading

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Thanks to Brandon Southall’s blog on his new SEA-inc website, which is fast becoming one of the best places to stay abreast of key ocean acoustics research, I heard today the details of what’s planned at the upcoming Minerals Management Service three-day workshop on Acoustic Mitigation and Monitoring Systems for Marine Mammals.  The workshop website now has the agenda online, and will include links to conference documents.  I was surprised and delighted to see that my most recent annual ocean noise report is first on the list of Background Documents to be read by attendees! This report, Ocean Noise 2008: Science, Policy, Legal Developments, can be downloaded from the conference site; it is also available, along with its brethren from 2006 and 2007, at AEI’s page on DocStock.com.  Several of my conference Powerpoint presentations are also now available for viewing and download as well, at AEI’s SlideShare page.

mms-acous-monit-conference1

The three-day workshop takes place in Boston later this month, and is bringing together most of the key players in the field, including Southall, Cornell’s Chris Clark, Oregon State’s Dave Mellinger, Aaron Thode of Scripps, Leila Hatch of Stellwagen Bank, passive device designers Peter Stein and Gordon Hastie, and several key oil and gas industry players, including Bill Streever (check out his great new book on the north, entitled Cold), David Hedgeland, and Bernard Padovani.

Blue Whale Call Rates Rise Dramatically Near Seismic Survey

Science, Seismic Surveys 5 Comments »

A new study published in Biological Letters found that a seismic survey in wide bay at the mouth of the St. Lawrence Seaway caused blue whales feeding and socializing nearby to double or triple their call rates.  The calls were near-range communication signals, rather than the long, loud songs that are heard over hundreds of miles. The research was meant to simply learn more about these social calls, but during the study, their recordings began to pick up the pulses from a seismic survey.  “The whales made more calls on days when the testing was happening. It seems they are having to repeat themselves in order to not lose information,” said lead researcher Lucia Di Lorio.  They also called more on survey days when the sounds were not audible than when they were, and tended to rapidly increase calls when the sounds appeared.

Blue whale at surface.    Image: Wikipedia Commons

Blue whale at surface. Image: Wikipedia Commons

Blue whales, the world’s largest animal, number just 5-10,000, are solitary for most of the year, making these summer-time feeding gatherings especially important; di Lorio notes that “We don’t yet know a lot about what these calls mean…They come to eat, but also to check out each other, maybe find a mate.”

The results were especially surprising, since the survey in question was using a much lower-power source than many surveys, and at levels much lower than those typically considered likely to cause problems.  ”It’s used [here] because it’s thought to have a lower impact on marine life,” di Lorio told the BBC, ”But we should definitely reconsider these things, because clearly it’s not only the sound level that’s important; and one thing might be not to do the test when there are lots of whales around.”

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