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Ocean observatory audio streams: navies nix bits of data that scientists savor

Bioacoustics, News, Ocean, Science, shipping, Sonar No Comments »

For several years, AEI has been excited about the ever-expanding networks of ocean observatories coming online around the world.  A recent article on LiveScience detailed some of the benefits of the arrays of research stations deployed offshore by Ocean Network Canada, which collect all manner of data: physical, chemical, biological, geological, and acoustic.  Their two networks, the offshore NEPTUNE (left below) and the near-shore VENUS (right below), consist of permanent installations on the floor (“nodes,” shown as orange squares below) as well as mobile moored sensors that may take measurements higher in the water column (yellow dots). A similar US network, dubbed Regional Scale Nodes, is being planned off the coast of Washington and Oregon.

NEPTUNE VENUS

While the observatories are enabling in-depth study of complex process in ways not previously possible (click that link for a glimpse of the amazing topics being explored…yes, do it!), the audio feeds coming from some of the nodes hold special excitement for many researchers. “If you want to study what’s going on in the ocean, the best tool by far is sound,” said Tom Dakin, an acoustic specialist at ONC’s sensors technology development office.”There are all kinds of sounds being made in the ocean, and they all have a telltale signature. . . . If you start putting in a bunch of external man-made noise, [whales] are going to have a hard time communicating,” Dakin said. It’s like trying to have a conversation with somebody at a rock concert — you have to shout, you can’t hold a conversation for very long and you wouldn’t be able to detect different inflections that you would normally be able to hear.  He has been diving when a big ship has gone by, and “it feels like somebody’s whacking you in the chest with a two-by-four,” he said.

navy listeningBut while scientists are keen to hear what the new undersea recordings have to tell us, the US and Canadian Navies are far less enthusiastic.  They’re concerned that the audio feeds, which are freely available to scientists and the public as downloads and via live online feeds, will reveal sensitive information about submarine and ship movements, navy training activities, and even the sound signatures of individual vessels. The two navies have arranged with researchers to have an audio bypass switch that allows them to divert the audio streams into a secured military computer—sitting in a locked cage at the research facility where the data comes ashore—at times when their ships are nearby (and also at some random other times, so that their diversions don’t give away any secrets on their own!).  This article from The Atlantic dug into the way this system works, along with a quick look at naval concerns about sound from as far back as 1918.  The data diversions from Ocean Networks Canada’s system (often triggered by the US Navy) occur several times a month and last from hours to days. As noted by The Atlantic:

While the Canadian military has yet to return a request for comment, the U.S. Navy reminds me that naval ship movements are classified information, and the fact that those movements might potentially be broadcast on the internet is obviously of concern. “The value of having a cabled system is that it releases data live to the internet,” says U.S. Navy oceanographer Wayne Estabrooks. “But there are some times where we want to protect information, so we have to do diversions.”

“There’s a long tradition of the ocean being the exclusive domain of the militaries and the fishing community, and we’re more or less interlopers in this world,” says [Kim] Juniper, the microbiologist who showed me the photo of the computer in the cage. “The world is changing. . . It’s going to come to a point in the future where this is no longer going to be feasible for the navies to put resources into sorting all this data,” he later says. The hydrophones alone generate 200 gigabytes of raw data each day, and there are other, similar networks of Internet-connected sensors that already exist, or are soon to come online.

Dakin notes, though, that only 4% of the data is lost, and is returned to the science pipeline, often immediately and nearly always within a week.  The military filters out their ship noise, but leaves the rest of the data intact (at least, whatever data is not also in the frequency range of the navy ships or other sensitive sonic activities). “At end of the day, we hardly miss any data at all,” he says.  You can listen to live streams of ONC acoustic data here, and, since that’s rarely very exciting, to a collection of highlights of images and sounds here.

A beautiful new view of humpback whale songs

Animal Communication, Bioacoustics, Ocean 1 Comment »

We’ve all heard that humpback whale songs have complex, repeating structures, and that the themes evolve over course of months and years. Yet listening to the gruts, guffaws, and groans of humpback recordings, it’s hard for most of us to really hear the large-scale structure that ties together these deeply alien sounds. In an article recently published on Medium David Rothenberg and Mike Deal have built on work done back in the 1970s by Scott McVay, and created a visual representation for humpback songs that makes it all suddenly and delightfully clear.

whale song staff WEBFor starters, Deal created glyphs to represent particular “song units.” Each of these distinctive utterances is shown in a different color; the shapes mimic the shape of the sonogram of the sound. Following on McVay’s work with Roger and Katie Payne, Deal and Rothernberg show how these units are combined to create “phrases” lasting 20-40 seconds; several phrases create a “theme,” and a sequence of themes lasting 5-30 minutes is the “song.” Deal and Rothenberg take McVay’s work one step further by overlaying the units on an expanded musical staff to represent the frequqency of each phrase (each utterance of the whales includes a broad range of tones, like a chord with many audible overtones, so the glyphs stretch over a substantial span of the musical staff).

Finally, they present full songs in this new notational language:

1413051978_thumb.jpeg
As Rothenberg notes, “The pattern in the phrases starts to seem like an alien language. But even eerier is how much more human-like the order appears than most known animal vocal behaviors.” Go read the full article; it includes several videos of note, including one that animates the above notation while the 8-minute song is played, and one that explores the compelling similarities between humpback song and mockingbird songs. Also featured are many of the original notations done by McVay, which inspired this new take on it, and exceprts from a recent lecture by Katie Payne (see it here) that dives deep into the questions of cultural change and linguistics that are raised by the extraordinary nature of the these songs.

Fantastic ocean noise presentation from Leila Hatch of NOAA

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

Earlier this month, Leila Hatch, one of NOAA’s leading experts on ocean acoustics and a long-time researcher in and around Stellwagen Bank National Marine Sanctuary, presented an hour-long talk on ocean noise.  It’s been archived on the Open Channels website, and is available for streaming and download on Vimeo.  

It’s by far the best introduction I’ve seen to this wide-ranging topic, including some basic information on ocean noise, along with a good summary of ongoing work at NOAA to map ocean noise and to learn more about how shipping noise, in particular, can impinge on whales’ communication space. Highly recommended!!

Listening to our Sanctuaries: Understanding and Reducing the Impacts of Underwater Noise in Marine Protected Areas from OpenChannels on Vimeo.

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.

New paper details the acoustic quality of critical whale habitats

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

AEI lay summary of:
R. Williams, C.W. Clark, D. Ponirakis, and E. Ashe.  Acoustic quality of critical habitats for three threatened whale populations.  Animal Conservation (2013).

Innovative research along the coast of British Columbia has quantified the degree to which shipping noise is reducing the distance at which whale vocalizations can be heard.  This is one of the first studies to use recordings of actual ocean noise levels to examine how the “communication space” of whales is affected by shipping noise in an area where whale conservation is a priority.  Among its troubling findings is that endangered orcas are facing the highest levels of noise in areas that are legally designated as critical habitat, with communication space reduced to 25% or less even in average noise conditions; over the entire study region, the area over which orcas can hear each other can be reduced by 62% during average noisy conditions, and 97% during the noisiest times.  Humpback whales face nearly as large reductions in some key areas (though not formally designated critical habitat; and, notably, are showing signs of a tenuous recovery in some of the areas studied), while fin whales, who have louder calls than the other species, are only mildly affected by shipping noise.

WilliamsCROP(noise levels and communication space in median noise conditions)

Communication space (alternatively termed “effective listening area”) is a relatively recent introduction into scientific parlance; it’s a measure of the area within which a particular species can hear and be heard by others of its kind; both marine and terrestrial bioacousticians have begun using this framework to better understand the ways animals may be affected by increased background noise introduced by human activities, including shipping, roads, and airplane overflights.  Previously, small increases in background noise were commonly considered to cause only negligible impacts, since there is rarely a clear or consistent behavioral reaction.  However, many animals rely on hearing things at the edges of audibility (calls of their kin, the approach of predators, the presence of prey), and a significant reduction in an animal’s communication space can cause a need to use more energy hunting, or to be in a heightened state of alertness (and stress) to avoid predation.

 

Read the rest of this entry »

After 100 years away, whales rediscover New Zealand, where they used to be the noise nuisance!

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SoRightWhale mom calfWEBSouthern right whales have begun giving birth in the waters around New Zealand.  Beginning in the 1920’s, none frequented waters around the New Zealand mainland, after an intensive decade of hunting in the 1800’s decimated populations.  In the 1990’s,  a few scattered sightings began, and in recent years, females and calves are started utilizing sheltered bays. According to Emma Carroll of Auckland University, the whales appear to have lost the knowledge that New Zealand was a valuable winter and calving habitat, but the early exploratory trips by individual whales seems to have led to it being “rediscovered.”

Ironically, considering the growing concern over the impacts of human noise on whales worldwide, early settlers in Wellington complained that whales in the harbor there kept them awake at night!  How the times have changed….

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

Name that animal sound

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Animalsoundgrid250You may have seen some press coverage recently of the latest iteration of Cornell’s Macauley Library of Natural Sounds online.  Today, Wired put together a fun little game in a slide show on their site, in which you can listen to clips of odd animals sounds, and try to guess whose voice you’re hearing.  The accompanying article is a good introduction to the new Macauley archive, too.  After reading the article, you can start playing the game by clicking “next” on the upper right corner of the animal picture grid on that page…

Detailed new maps highlight excessive shipping noise in Puget Sound, BC coast

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

OrcasTankerHaroBeamreachIn the wake of NOAA’s large-scale ocean noise mapping project, two much more detailed studies from the Pacific Northwest have highlighted the likelihood that current shipping noise is already pushing the limits of what biologists think many ocean creatures can cope with.

The first study recorded the sound from several types of boats and ships traversing Admiralty Inlet, between Whidbey Island and Port Townsend, WA, and used these recordings, correlated with ship traffic records, to model sound levels throughout the area.  The Seattle Times summarizes this work, which found that at least one large vessel (container ship, ferry, or large tug) was in the area at least 90% of the time, and that the average noise level was about 120 decibels, which is the threshold above which federal agencies begin being concerned about behavioral impacts on some ocean species.  

“Continuous noise at that level is considered harassment of marine mammals,” said University of Washington’s Christopher Bassett, one of the authors of the paper. “About 50 percent of the time, we even exceed that threshold.”

“It is concerning that the noise levels are so high,” said Marla Holt, a research biologist at Seattle’s Northwest Fisheries Science Center. “When you see how often this happens and how chronic the noise exposure is, that’s when you start to say, ‘Wow.'”

Interlude: Brief OrcaLab recording of threatened Northern Resident killer whales in Caamano Sound, BC, chatting with each other and then being drowned out by a cruise ship:
 

To the north, another study mapped shipping noise in the Salish Sea (south and east of Vancouver Island), and on up the British Columbia coast to the port of Prince Rupert.  This work, funded by World Wildlife Fund-Canada, introduces a comprehensive approach to modeling sound transmission from ships, incorporating differences between vessel types, transmission loss in a variety of bathymetric and seabed conditions, and temperature-driven variations in sound speed during different seasons. (Download a PDF presentation summarizing the full WWF-Canada report here; a shorter version appeared in JASA in November). Here, too, large areas are subject to excessive shipping noise; the maps below show total sound levels, and the areas where the annual average of two specific low frequencies are above the 100dB threshold that the European Union considers the target for biologically sensitive areas:

Erbe JASA 2012 BC ship noise 500px

But now, check out that lighter colored patch about halfway between BC’s two big offshore islands.  

Erbe closeup 150That’s an inland waterway that heads up to Kitimat, the proposed site of a major new port, the Northern Gateway, which would serve as the primary port for shipping tar sands oil to Asia.  An annual total 220 super-tankers would head though that currently mostly-yellow zone, all the way up that long, narrow channel that points to the upper right hand corner of this close-up (and leave againso more than one passage a day on average).  As you might imagine, there is widespread concern about the risks of accidents and spills in these often treacherous passages, but the increase in shipping noise is also being raised as a question.

Erbe monthly increase 250A second study by the same research team, led by Christine Erbe, took a close look at current and likely increases in shipping noise, should Northern Gateway go forward, and what they found is not reassuring.  Noise levels will increase by up to 6dB in the approach lanes in Caamano Sound, and by 10-12dB in the narrow fjord into Kitimat (see map on right).  In the western channel (the wider approach), where sound would likely increase 3-6dB (representing a doubling to quadrupling of sound energy), Humpbacks would hear tankers and their accompanying two tugboats for 43% of daylight hours, and orcas (due to thier higher-frequency hearing, less intruded upon by low-frequency ship noise) would hear the tankers 25% of the time.  Fewer whales venture all the way up the fjords, but some would likely be present in the bend in the route, where noise levels would increase by 10dB, representing a 10-fold increase in sound energy.

“There is a worry they will go away and not come back to these fiords,” says Erbe. “This is critical habitat, important to them. Are they going to be able to feed elsewhere? We can only answer that with long-term monitoring.”

These studies, one of which utilized four seasons of recordings, and the other presenting a comprehensive and verifiable sound modeling approach, both offer exciting steps forward in the study of coastal and oceanic acoustic habitats.  Let’s hope that coming years produce many more studies from other regions around the world that continue to develop these innovative techniques.

Detailed Northern Gateway study: Erbe, C., Duncan, A., and Koessler, M. 2012. Modelling noise exposure statistics from current and projected shipping activity in northern British Columbia. Report submitted to WWF Canada by Curtin University, Australia.

BC sound modeling study: Erbe, C., MacGillivray, A., and Williams, R. 2012. Mapping Ocean Noise: Modelling Cumulative Acoustic Energy from Shipping in British Columbia to Inform Marine Spatial Planning. Report submitted to WWF Canada by Curtin University, Australia.
Shorter version:   Erbe, C., MacGillivray, A., and Williams, R. 2012. Mapping cumulative noise from shipping to inform marine spatial planning.  J. Acoust. Soc. Am. 132 (5), November 2012. 423-428.

Puget Sound study: Bassett, C., Polagye, B., Holt, M., Thomson, J. 2012. A vessel noise budget for Admiralty Inlet, Puget Sound, Washington (USA). J.Acoust.Soc.Am. 132(6), December 2012

Related:
Kathy Heise and Hussein Alidina.  Ocean Noise in Canada’s Pacific Workshop, January 31-February 1, 2012.  Summary Report.  WWF-Canada.  54pp.  Read or download PDF

WWF-Canada Submission to Enbridge Northern Gateway Joint Review Panel, 9/19/12. (mostly terrestrial impacts; some ocean noise sections) Read or download PDF

Quiet ocean experiment

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Boston’s WBUR recently interviewed Jesse Ausubel, of Rockefeller University and Woods Hole Oceanographic Institution, about an ambitious project dubbed the Quiet Ocean Experiment.  The idea is to dedicate a year to making detailed observations of wildlife responses to temporary reductions in normally noisy ocean activities, and ideally, to spur a period of several hours to a day during which nearly all human activity in the oceans might cease, in order to see what effect that may have.  Rather than studying the impacts of new noise sources, Ausubel and his colleagues hope to see what removing sound might do.

Here’s a link to a transcript of the five-minute interview.  Or listen below:

New NOAA maps offer compelling picture of ocean noise

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NOAA noise mapsIn December, NOAA announced the release of the first large-scale ocean noise maps, which have been in development for the past two years.  The Underwater Sound Field Mapping Working Group modeled many sources of sound occurring within 200 miles of the US coast (including ships, seismic surveys, sonar, pile driving, and oil platform decommissioning), as well as modeling shipping noise in full ocean basins (including the Atlantic, pictured at left).  Data  is compiled in several depths and frequency ranges, to account for the full spectrum of various species’ habitat usage and hearing/vocalization ranges.

Dr. Leila Hatch, co-chair of the Working Group, said too many areas of the ocean surface (where sea mammals and whales spend most of their time) are orange in coloration, denoting high average levels. “It’s like downtown Manhattan during the day, only not taking into account the ambulances and the sirens,” she said. “I’d be happier saying it was like a national park.”

Michael Jasny, a senior policy analyst with the Natural Resources Defense Council, which has sued the Navy to reduce sounds that can harm marine mammals, praised the maps as “magnificent” and their depictions of sound pollution as “incredibly disturbing.”

“We’ve been blind to it,” Mr. Jasny said in an interview. “The maps are enabling scientists, regulators and the public to visualize the problem. Once you see the pictures, the serious risk that ocean noise poses to the very fabric of marine life becomes impossible to ignore.”

NOAA has set up a website where this ongoing work will be made available.  In addition, an 85-page report brings together presentations and recommendations from a two-day symposium held last May, at which the Working Group presented their draft results to a couple hundred other experts from agencies, the Navy, oil and gas industry, academia, and nonprofit groups (I was fortunate to be invited to participate in that meeting).

Equally exciting is a companion project by a Cetacean Density and Distribution Mapping Working Group, also introduced at the May symposium, that is working to compile all known studies of whale and dolphin population distribution.  Tens of thousands of cetacean observations are being compiled into month-by-month distribution charts and maps for various ocean regions around the US.  In addition, seasonally biologically important areas (e.g., for breeding, feeding, or mating) are being compiled as part of this work.

The two mapping projects will provide a robust new foundation for assessing the impacts of noise sources, and hopefully to encourage efforts to reduce human noise, especially in biologically important areas.  A New York Times article introducing the noise mapping project includes encouraging words from Michael Bahtiarian, an adviser to the United States delegation to the International Maritime Organization, which is looking at ways to reduce ship noise and vibrations.  “Right now we’re talking about nonbinding guidelines,” he said  “At a minimum, the goal is to stop the increases.”  See earlier AEInews coverage of the IMO efforts from 2008, 2009, and 2012.

SEE ALSO: Detailed ocean noise maps take this approach further in Puget Sound, BC coastal waters 

Ancient whale song: louder than modern human-caused ocean noise?

Bioacoustics, Ocean, Ocean energy, Science, shipping Comments Off

AEI lay summary:
M.S. Stocker, J.T. Reuterdahl. Is the ocean really getting louder? 164th Meeting of the Acoustical Society of America, Oct. 22-26, 2012.  ASA press release

A paper presented at this fall’s Acoustical Society of America meeting has triggered a wave of provocative headlines about how whale-filled oceans of the past may have been “as loud as a rock concert” or how “Noisy whales made FAR MORE oceanic racket than humans do.”  The paper does indeed ask an innovative question: what was the ocean soundscape like in the pre-whaling days?  And its answer, while couched in a high degree of uncertainty, is also eye and ear-opening: ten times as many whales made a lot more noise than today’s diminished populations, perhaps adding up to overall noise levels that match those caused by today’s shipping, oil and gas exploration, and other human activities in the seas.

It’s probably a bit too acoustics-geeky for me to object to the “rock concert” comparison, but for the record, the paper itself never uses those two words alone or together!  (Though somehow the phrase slipped into the ASA press release; we’ll have to blame the editor or an author’s pre-conference sleep deprivation for the slip…)  In fact, thanks to their differences in density, measurements of sound in water are about 62dB higher than a similar sound level in air; thus, the mention of 126dB of whale sounds filling the ancient oceans would not be equivalent to a rock concert, but more like the 64dB sounds of laughter or a loud conversation.  Which, as it turns out, much better captures the essence of the historic soundscape as described by the authors:

The bio-acoustic environment of the pre-industrial whaling ocean could be correlated to the animal sounds in any biologically diverse and well populated habitat wherein the riot of birdcalls, the stridulation of insects, and the mammal vocalizations are the dominant noise contributors to the soundscape.

The question of ancient ocean sound levels is relevant because much of today’s thinking about the impact of human noise is predicated on research that shows global shipping increasing the ambient noise levels in the oceans by 10dB or more since the 1950’s.  This just happens to be the era in which whale populations were at their nadir, with several species having already become rare enough that it was no longer worth the effort to find and hunt them.  But as the authors stress in their conclusion, an ancient ocean full of whale song — along with the more widespread  sounds of the onomatopoeia-ic large fish, Grunts and Drums, or the “great schools of tuna miles across (that) would churn up the sea surface for days as they migrated past California’s Channel Islands” noted by early 20th century fishermen, which the authors note “would likely be as loud as or louder than even the most tempestuous sea state” — is a very different place than an ocean full of the noise of ship engines and airgun reverberations.

Animals have evolved to fill distinct acoustic niches, with their songs and calls at different frequencies, made at different times or the day or year, and using distinct rhythmic pulses; each species’ hearing is especially tuned, or filtered, to pick out the calls of its own species from the voices of others.  But, as the authors note, “the signature of mechanized ocean noise interference from shipping is broad-band, pervasive, and chronic, and more likely to mask across animal frequency and/or time domain filters throughout large areas of the ocean.”

Or as put so well by Tim Baribeau, it’s important to remember that “we could still be disorienting whales with our bizarre and intrusive industrial sounds. But it’s incredible to think that the oceans may once have been filled with a cacophonous background chatter of animal noise.”

On the water with orca D-tag research crew

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Oregon Public Broadcasting recently sent reporter Ashley Ahearn out with the researchers that are listening in on orca activity underwater (covered here last month), and her wonderful, detailed report is now online; check it out!  It includes two videos, one showing a tagged orca’s swimming track, along with every boat in its vicinity over the several hour journey, and the other offering a “poles-eye view” of attaching the D-tag to an orca:

D-TAG study listens to what Puget Sound orcas hear

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OrcapictureBrad Hanson and colleagues at NOAA’s Northwest Fisheries Science Center are currently conducting a second year of exciting new acoustics field research with the Southern Resident killer whales of Puget Sound.  As they did last year, researchers are attaching suction-cup digital acoustic recording tags (DTAGs) to orcas; the tags remain attached for up to four hours, all the while collecting both dive profile data and recording the sound heard (and made) by the animal.  Hanson says that “we’re interested in trying to figure out if the noise levels are interfering with the whale’s ability to communicate effectively during foraging and or actually interferes with their foraging.”

Astonishing bowhead whale song diversity discovered

Bioacoustics, Science 1 Comment »

FramWhen a University of Washington researcher listened to the audio picked up by a recording device that spent a year in the icy waters off the east coast of Greenland, she was stunned at what she heard: whales singing a remarkable variety of songs nearly constantly for five wintertime months.  In a paper just published in the journal Endangered Species Research, and freely available online, Kate Stafford and her co-authors report on acoustic monitoring that took place in the winter of 2008-9 in the Fram Strait, between Greenland and Spitzbergen, a key channel for water circulation between the Arctic and Atlantic Oceans.  

Quite unexpectedly, Stafford found that bowhead whales were singing “almost constantly from the end of November until early March,” with over 60 distinct songs being recorded during these months of deep winter darkness.  It is presumed that these were mating calls, as are the famous humpback whale songs.  However, the researchers stress:

The song diversity noted here is unprecedented for baleen whales. Whether individual singers display 1, multiple, or even all call types, the size of the song repertoire for Spitsbergen bowheads in 2008 to 2009 is remarkable and more closely approaches that of songbirds than other baleen whales.

Also fascinating is the stark difference in types of calls in the two recording locations.  The diverse and continuous singing took place under “a dense canopy of ice cover, (which) may provide a better acoustic habitat for the transmission and reception of song when compared to loose pack ice.” Lead author Kate Stafford notes, “It’s clear there’s a habitat preference. As Arctic sea ice declines, there may be some places like this that are important to protect in order to preserve a breeding ground for the bowhead whales.” 

Download the paper
Read a summary of the work from University of Washington
Listen to a couple of sound samples

 

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

Whales can dampen hearing: implications for ocean noise concerns

Animal Communication, Bioacoustics, Effects of Noise on Wildlife, Ocean, Science Comments Off

You may have noticed a recent flurry of press reports about research in Hawaii that begins to quantify a long-suspected quality of cetacean hearing: the ability to dampen hearing sensitivity so that loud sounds don’t cause damage.  Given the extremely loud volume of many whale calls, which are meant to be heard tens or hundreds of miles away, researchers have long speculated that animals may have ways of protecting their ears from calls made by themselves or nearby whales, perhaps using a muscle response to reduce their hearing sensitivity (not unlike a similar muscular dampening mechanism in humans).  Indeed, earlier studies by Paul Nachtigall’s team had found that some whales could do indeed reduce their auditory response to the sharp clicks they use for echolocation.  In the new study, Nachtigall trained a captive false killer whale named Kina to reduce her hearing sensitivity by repeatedly playing a soft trigger sound followed by a loud sound.  Eventually, she learned to prepare for the loud sound in advance by reducing her hearing sensitivity.  “It’s equivalent to plugging your ears…it’s like a volume control,” according to Nachtigall.

Well, that sounds like a pretty useful trick, given all the concern about human sounds in the sea.  And the media, led by the New York Times, jumped on board with headlines following on the Times‘ assertion that suggested whales  already “are coping with humans’ din” using this method. (Among the exciting headline variations: Whales Can Ignore Human Noise, Whales Learning to Block Out Harmful Human Noise, and UH Scientists: Whales Can Shut Their Ears.)

Oops, they did it again!  Grab some interesting new science and leap to apply a specific finding to a broad public policy question, often, as this time, giving us a false sense of security that the “experts” have solved the problem, so there’s no need to worry our little selves over it any more (as stressed in this NRDC commentary).  To be fair, the Times piece included a few cautionary comments from both scientists and environmental groups, but the headline rippled across the web as the story was picked up by others.

Two key things to keep in mind:  First, this whale was trained to implement her native ability, meant for use with her sounds or those of nearby compatriots, and to apply it to an outside sound made by humans.  This doesn’t mean that untrained whales will do the same.  

And second: If whales can dampen their hearing once a loud sound enters their soundscape, this could indeed help reduce the physiological impact of some loud human sounds, such as air guns or navy sonar. If indeed this ability translates to wild cetaceans, the best we could hope for is that it would minimize hearing damage caused by occasional and unexpected loud, close sounds that repeat.  There would be no protection from the first blast or two, but perhaps some protection from succeeding ones; or, if the sound source was gradually approaching or “ramping up,” as often done with sonar and air guns, animals may be able to “plug their ears” before sounds reach damaging levels, if for some reason they can’t move away.  Even then, the animals are very likely to experience rapidly elevated stress levels, as they would be less able to hear whatever fainter sounds they had been attending to before the intrusion. Yet research in the field suggests that most species of whales and dolphins prefer to keep some distance from such loud noise sources; this hearing-protection trick doesn’t seem to make them happy to hang around loud human sounds.  

Most crucially, these occasional loud sounds are but a small proportion of the human noises whales are trying to cope with. Noise from shipping, oil and gas production activities, offshore construction, and more distant moderate sounds of air guns all fill the ocean with sound, reducing whales’ communication range and listening area, and likely increasing stress levels because of these reductions.  This is the “din” of chronic moderate human noise in the sea, and Kina’s ability would not help her cope with any of it.  We’re a long way from being able to rest easy about our sonic impacts in the oceans.

To end this rant with a bit of credit where due, here’s what may be the more important take-away from the Times article:

Peter Madsen, a professor of marine biology at Aarhus University in Denmark, said he applauded the Hawaiian team for its “elegant study” and the promise of innovative ways of “getting at some of the noise problems.” But he cautioned against letting the discovery slow global efforts to reduce the oceanic roar, which would aid the beleaguered sea mammals more directly.

Floating in whalesong

Bioacoustics, Human impacts, News, Ocean Comments Off

Humpback 460x230 fct372x229x52 t325

For a welcome change of pace from stories about contentious acoustic ecology issues, check out this column from Australia about a group of people who were treated to two sessions of whale song while floating near their inflatable raft. Here’s a teaser:

“This time the singer was right before my eyes, and the singing was so powerful you could actually feel it in the water. As I drifted on the surface, the sound vibrated through my body. It was an amazing experience.”

Bernie Krause’s Great Animal Orchestra

Arts, Bioacoustics, Effects of Noise on Wildlife, Wildlands Comments Off

Bernie bookBernie Krause’s new book, The Great Animal Orchestra, is a worthy culmination to his inquisitive career.  After working out a few writerly wrinkles on a couple of earlier books that touched on aspects of his fascination with the world of natural sound, this one offers up a wide-ranging tour of our sounding world, shared in a congenial voice.

This book has rightfully garnered widespread praise, including the coveted cover spot on the NY Times Book Review section, as well as write-ups in The Washington Post, The Ecologist, The San Francisco Chronicle, and Wired. Check each of these out for good, brief glimpses into the stories you’ll find between these covers. The Wired piece is particularly well done, with many sound samples; more sounds can be heard on the site of publisher Little Brown.

Several key themes provide the foundation of the book.  First and foremost is Krause’s segmentation of the soundscape into geophony (sounds of wind and water and other movement of natural objects), biophony (sounds of animals, both vocal and sounds of movement), and anthrophony (sounds of humans, especially mechanical and amplified sounds). Similar divisions are used by bioacousticians, as evidenced in a couple of talks at a recent Bureau of Ocean Energy Management workshop on sound and fish that I attended.  Likewise, Bernie is an eloquent spokesman for the widespread thought that early human music has its roots in a time when tribal peoples considered themselves but one voice in a local sounding landscape; this theme is emphasized in the subtitle to the book, “Finding the Origins of Music in the World’s Wild Places.”

Krause’s reflections on our urbanized relationship to sound are grounded in the soundscape tradition of R. Murray Schaffer, while his continuing efforts to understand the dynamics and relationships in natural soundscapes – using spectrograms to illustrate possible use of acoustic niches (differences in pitch, rhythm, or time of day) that allow a plethora of creatures to each be heard within a complex biophony – are contributions to the leading edges of scientific investigation of soundscape ecology.  Many reviewers note the rambling quality of the book as a small downside, but I found that it brought me as a reader into Bernie’s world, where pure wonder at the diversity of sounds crosses paths with speculative theories, sorrow at what’s disappearing, and a commitment to draw us into a deeper communion with the sounding world that surrounds us. A mindful engagement with sounds, or with the world as it is today, will inevitably bring us to such a mix of thoughts, feelings, and inquiries; this book one of the best invitations into the acoustic aspects of our times.

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

Bioacoustics, News, Ocean, Science, Seismic Surveys, shipping, Sonar Comments Off

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.

Fish survey sounds reduce humpback songs 120 miles away?

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

AEI lay summary of the following paper:
Risch D, Corkeron PJ, Ellison WT, Van Parijs SM (2012) Changes in Humpback Whale Song Occurrence in Response to an Acoustic Source 200 km Away. PLoS ONE 7(1): e29741. doi:10.1371/journal.pone.0029741
Read or download online (free)

An ongoing research project that monitors whale calls and shipping noise in Stellwagen Bank east of Boston Harbor has reported an unexpected reduction in humpback whale songs during an 11-day period in which their recorders picked up low frequency sounds from a fish-monitoring system 120 miles away.  If this data does indeed represent whales ceasing singing or moving away in response to the distant sonar, this would be the first clear-cut indication that discrete human noise events may affect marine mammal behavior outside the immediate area.  The authors note that these results could suggest that impact assessments need to consider effects at longer ranges, and that effects may occur at received sound levels much lower than those generally considered worthy of concern.  This study simply reports the reduction in singing; any longer-term effect that may have on the animals is unknown (these are not mating calls).

The reduction in songs occurred at a time of year (early fall) when humpback songs are beginning to increase in this area; on years when the fish sonar was not in operation, the numbers of songs steadily increased over the 33-day study period.  But in 2006, when the fish sonar was heard at Stellwagen Bank for 11 days (8 of which included sonar sounds for over 7 hours), the number of minutes per day when humpbacks were singing dropped, some days to zero.  The average (mean) number of hours of whale song dropped from about 75 in the previous 11 days to about 15 minutes during the time the fish sonar was heard, before increasing to close to 3 hours per day once the sonar transmissions ceased.

The figure below shows the data from each of three years.  For each year, there are 33 days of data, with the middle 11 days being the period (Sept. 26-Oct 6) in which the sonar sound occurred in 2006.  The open circles are the mean minutes/day for each 11-day period, with the rectangular boxes representing the upper and lower quartiles of data for each period; black dots represent one or two days in each period in which the calling rates for that day were unusually far outside the range for other days in that period.

Risch 2012 dataWEB

Ed. note: Interpreting the results of vocalization studies is complicated by the fact that there is much variability in vocalizing rates, and response/sensitivity to human noise, from one animal to another; and similarly, in numbers of whales in the area from year to year.  (This acoustic data counts singing minutes, but not animal numbers, which must be monitored visually.)

Read the rest of this entry »

Join citizen science project to ID whale calls

Animal Communication, Bioacoustics, Ocean, Science Comments Off

Over the past few years, new and relatively inexpensive new hydrophone systems have allowed biologists to place autonomous recorders in far more locations, collecting vast amounts of acoustic data that can help them to understand the population dynamics of marine mammals, as well as to monitor interactions and effects of human noise on marine mammal communication.  They’re also looking forward to learning more about individual and pod communication patterns.

But this flood of new data hits a bottleneck when it needs to be assessed by human listeners.  There are several robust automated call detection programs available, but even these must be checked by humans, who can hear similarities in calls or see patterns in the sonograms that present the complex calls as pictures of the frequency patterns.

To the rescue comes a new crowdsourcing project from Scientific American and Zooniverse, WhaleFM.  Individuals from around the world are invited to join the research teams from Woods Hole and the University of St. Andrews by matching new recordings of orcas and pilot whales with  known calls or call types (often associated with particular behaviors). While orca society is moderately well-understood, with many call types already identified, this aspect of pilot whale research is at an earlier stage, and users will help to decide which Pilot Whale calls match, and help in discovering whether the same call is make by one individual, one group, or across broad areas. For more on the project, check the link above, or this blog post from Scientific American.

Moderate noise changes bird communities

Bioacoustics, Effects of Noise on Wildlife, Science, Wind turbines Comments Off

Research summary of Francis, C.D., Ortega, C.P., Cruz, A. 2011. Noise pollution filters bird communities based on vocal frequency. PLoS ONE 6(11):e27052.

An ongoing research project in New Mexico continues to shed more detailed light on the question of how moderate human noise affects nearby wildlife.  In a study design that effectively separates out the impact of the noise from other habitat disruption effects, Clint Francis and his colleagues are finding that some species are displaced, while others seem to thrive in areas with coalbed methane compressor stations creating noise around the clock.  The most recent paper to be published by Francis et al finds that species that sing at lower frequencies are most likely to avoid the noisy areas, while those who vocalize at higher frequencies are more apt to be unaffected or even thrive.

While this research studies an area with oil and gas development noise, it’s likely that similar effects would occur in and near wind farms, which also produce predominantly low-frequency noise. And, as the authors note to conclude their paper: “At the community-level, we must still determine whether noise is an agent of ecological filtering for other taxa that rely on acoustic communication.”

Rather than doing the full AEI lay-summary of the most recent paper, I want to point you to the great summary already written by Caitlin Kight, biologist who studies the effects of anthropogenic disturbances on animals; it was recently featured on her Anthrophysis blog.

David Dunn, the tree whisperer? (great bark beetle story, though!)

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David Dunn is a longtime friend and colleague to AEI here in Santa Fe, and in fact his underwater insect recordings were my first taste of the sounds of the natural world having the potential to be deeply strange and amazing, rather than “just” beautiful. So when he discovered that the bark beetles chewing their way through the piñon pines in the hills of New Mexico were making all sorts of bizarre sounds, and suggested publishing a CD to benefit AEI, I was all for it.

Since then, the bark beetle inquiry has taken on a life of its own, becoming a perfect expression of David’s longtime conviction that artists can contribute in significant ways to science.  The acoustic behavior and communication of bark beetles was previously unstudied by entomologists, and now he’s being called to consult with scientists studying not only the piñon pine beetle, but also the mountain pine beetles ravaging larger higher-elevation and higher-latitude pines, as well as insect pests of the non-beetle persuasion.

This past week, a long article appeared in several Canadian newspapers, providing the most detailed look yet at David’s beetle odyssey.  It’s an excerpt from a new book by Andrew Nikiforuk, Empire of the Beetle: How Human Folly and a Tiny Bug Are Killing North America’s Great Forests.  The article dubs David “the tree whisperer,” though so far he hasn’t quite figured out how to calm the outbreaks; in fact, the research so far seems to be leading more toward driving beetles crazy than calming them.  But after forgiving the headline writer, we can sink into he article itself, which is the most detailed, entertaining version yet of David’s beetle adventures.