NOAA has issued Incidental Harassment Authorizations to five oil and gas exploration companies, each of which plans to engage in several weeks to several months worth of surveys off the US Atlantic coast during the one-year permit period, which extends through 2019.  When the Trump administration initially announced its rollback of the Obama-era decision to forego new exploration, it seemed that the lack of Atlantic leasing opportunities in the 2017-2022 National Outer Continental Shelf Oil and Gas Leasing Program would undermine the economic incentives to invest in new surveys (and AEI wrote a detailed “don’t worry too much” post).  But the Trump team threw out years of agency staff and scientist work and is now rewriting the OCS leasing program three years early: their new Draft 2019-2024 plan opens up six lease areas in the Atlantic in 2020, 2022, and 2024; new surveys will guide both the government and oil companies as they identify which areas are ripe for development.

However, it is inevitable that court challenges from environmental groups and perhaps coastal states will slow the process down or derail it completely.  So stay tuned….

The surveys being proposed are broad-brush preliminary overviews of the region, and so involve somewhat less intense sound-blasting than detailed site-specific surveys; most of the tracklines are 20-30km apart, and some 100-200km apart, though one survey narrows the spacing to 6km in the core area (see center, below).  But they cover vast areas of the sea, on and beyond the continental shelf.  Here are  sample maps showing the survey lines being proposed:

Most of the activity is well offshore, which helps minimize impacts; from November through April they are pushed a full 90km offshore to keep high levels of noise out of North Atlantic Right whale winter breeding and nursing areas; several other smaller areas are off limits either year-round or seasonally.

Behavioral impact estimates are surprisingly low (and so perhaps a target of legal challenge): under a dozen right, sei, and blue whales, and a few thousand behavioral changes among far more numerous fin and sperm whales; sea turtles are expected to take the biggest hit, especially in far offshore sargassum habitat, with tens of thousands being disrupted and thousands experiencing temporary hearing reductions.

All this region-wide noisemaking, of course, in service of the madness that is continued oil and gas development in the face of a global climate imperative to leave untapped reserves in the ground.  The US is already the world leader in oil and gas production and we have thousands of existing leases that have yet to be developed; the last thing we need is more straws in the ground—especially in deep offshore waters. I have to admit, though, that I am no longer as sanguine about the Trumpistas’ offshore crusade as I was when these plans were first floated a year ago.

UPDATE, 12/14: For those of you wanting to raise your voice about this, you can count on our compatriots at Ocean Conservation Research to keep you updated on the field of play for public discourse.

An AEI big-picture commentary

Once again, a Presidential announcement about offshore oil development has sent the media and environmental advocates into a spasm of headlines and press releases that presumes the words being uttered in DC actually reflect on-the-ground (or in this case, under-the-waves) reality. In late 2016, there was effusive praise for an effectively symbolic Obama decision to not offer leases in Alaskan and Atlantic waters (AEI’s “much ado about not much” post questioned the prevailing celebratory outburst). Fourteen months later, we’ve got a mirror-image outcry over Trump’s base-pumping proclamation about “unleashing America’s offshore oil and gas potential” through a National Outer Continental Shelf (OCS) Oil and Gas Leasing Program for the years 2019-2024.

This one sure does sound bad: opening up 90 percent of our continental shelf, with 47 lease areas including regions like New England and the Pacific Northwest that haven’t even had vague proposals for decades. Despite the boom in American oil and natural gas production that occurred during the Obama years, with much of the increased production being exported, the new administration is intent on exploiting as-yet untapped deposits, ignoring the climate imperative to leave as much oil in the ground as we can. Vincent DeVito, a Counselor for Energy Policy at the Department of Interior, practically twirls his mustache with this comment from the official DOI press release:

“By proposing to open up nearly the entire OCS for potential oil and gas exploration, the United States can advance the goal of moving from aspiring for energy independence to attaining energy dominance. This decision could bring unprecedented access to America’s extensive offshore oil and gas resources and allows us to better compete with other oil-rich nations.”

Sure, that’s just the ticket; these eager beavers can’t wait to dominate a fading industry—a decade from now, since that’s how long it takes to get offshore wells on line.

And so begins a two-year planning process that will needlessly and expensively repeat the one just completed in 2016.  For we already have a National Outer Continental Shelf Oil and Gas Leasing Program, with a finalized plan set to run from 2017-2022, which the government (both federal and states), oil industry and energy consulting firms, and environmental groups spent two years and who knows how much money to complete.  As always, these plans are revisited, revised, and occasionally overhauled every five years. But this gang may not be around in 2021-2022 when it’ll actually be time to once again jump into this particular vat of no-fun-for-anyone. So let’s just tear it up and do it all again now!

UPDATE, 2/16/18: Caroline Ailanthus rightfully notes that diving back into processing hundreds of thousands of public comments and writing up a new programmatic EIS will keep BOEM staff from fulfilling their many other tasks, which include assessing new science and identifying key data gaps, smaller project-level environmental assessments, and overseeing new research. She asks, “Do you suppose interfering with research in this way could be the point of this massive do-over?”

But before we get too caught up with the swarm of freaked out bees in our bonnet, let’s step back and consider the actual energy development landscape as it exists in the real world, as distinct from the fever dreams of this administration’s oil and gas cheerleaders. Read the rest of this entry »

A recent line of research ups the ante on how widespread the impacts of human noise in the ocean may be. Oysters appear to suddenly and dramatically close up in response to low frequency noise at intensities that are relatively common—beginning at sound as levels as low as 120dB, and ramping up rapidly above 140dB. The figure at left shows how fast the shells closed at top and the degree of closing at bottom (from the minimal to maximal responses observed). Effects were strongest from 10-200Hz, a frequency range that includes shipping and seismic survey sounds.

While oysters, like many other shellfish and crustaceans, do not have ears, they are sensitive to vibrations; earlier oyster studies speculate that they may be responding to subtle seabed vibrations, though it’s also possible their tissues are responding to water-borne particle motion. Another recent paper looked at scallop behavior and mortality after exposure to airguns, and reports that negative effects were seen for months after exposure:

“Exposure to seismic signals was found to significantly increase mortality, particularly over a chronic (months postexposure) time scale, though not beyond naturally occurring rates of mortality. Exposure did not elicit energetically expensive behaviors, but scallops showed significant changes in behavioral patterns during exposure, through a reduction in classic behaviors and demonstration of a nonclassic “flinch” response to air gun signals. … Hemolymph (blood analog) physiology showed a compromised capacity for homeostasis and potential immunodeficiency, … with effects observed over acute (hours to days) and chronic (months) scales. … Given the scope of physiological disruption, we conclude that seismic exposure can harm scallops.”

As our colleagues at Ocean Conservation stress in their coverage of these new developments, all this is part of a rapidly expanding awareness of the ways that our noise compromises ocean life far beyond the whales and dolphins that were the focus of initial concern and research. Early this year saw the publication of a comprehensive review of the potential impacts of marine seismic surveys on fish & invertebrates. The authors point out that on many topics (fish catch rates, startle responses, tissue damage) results have been mixed/contradictory, with some studies finding negative impacts and others finding no response; their paper lays out key areas for future research that could begin to clarify these ambiguities.

The authors of a 2016 study on the effects of shipping and construction noise on lobsters and clams paint the picture quite clearly:

Tim Leighton, Professor of Ultrasonics and Underwater Acoustics and study co-author, said: “There has been much discussion over the last decade of the extent to which whales, dolphins and fish stocks, might be disturbed by the sounds from shipping, windfarms and their construction, seismic exploration etc. However, one set of ocean denizens has until now been ignored, and unlike these other classes, they cannot easily move away from loud man-made sound sources. These are the bottom feeders, such as crabs, shellfish and invertebrates similar to the ones in our study, which are crucial to healthy and commercially successful oceans because they form the bottom of the food chain.” Co-author Dr Chris Hauton, Associate Professor in Invertebrate Ecophysiology and Immune Function, added: “I think these findings raise the prospect that anthropogenic sounds in the marine environment are impacting marine invertebrate species in ways that have not been previously anticipated.”

The Leighton and Hauton study, using sound playbacks mimicking a ship at 100 yards and wind farm construction at 60 yards, found that both lobsters and clams changed their digging behaviors, and triggered changes in their overall activity level (lobsters increased, clams decreased); they found no marked effects on brittlestar activity.

Clearly, we are still in the early stages of understanding how our noises may be changing ocean ecosystems. In addition, the recent review paper affirms a longstanding concern that noise may act as a synergistic stressor, making animals more susceptible to other known stressors such as food shortages or rising ocean temperatures, noting that “Single stressors related to sound exposure may show no effects in isolation but when combined with other stressors effects may become pronounced.” New study designs are beginning to tease out these inter-relationships, giving researchers and ocean managers new tools that can move both science and policy forward in constructive ways.

Tip o’ the hat to longtime partner in crime Ocean Conservation Research for catching this insult to the ears of whales, seals, fish, and crustaceans. As part of its hatchet-wielding rampage through America’s regulatory arena, the Trump administration has gone beyond “merely” making plans to re-open the Arctic to drilling and issue new permits for seismic surveys off the Atlantic coast (both of which will doubtlessly engender legal challenge). Now they’ve also come for us!

The recent Presidential Executive Order Implementing an America-First Offshore Energy Strategy explicitly calls for the Secretary of Commerce to “take all steps permitted by law to rescind or revise” NOAA’s Technical Guidance for Assessing the Effects of Anthropogenic Sound on Marine Mammal Hearing.  This planning document was the result of many years of collaboration among regulators, research scientists, environmental organizations, and the primary ocean noise-makers (oil and gas interests and the Navy).  As OCR’s Michael Stocker notes, “All of this work threatened with a stroke of a pen…”

There’s nothing in the NOAA Guidance document that would stop, or even slow, current oil and gas exploration or Navy testing and training activities. It more or less serves as a formal declaration of the current state of the science and a framework within which further research can be prioritized and carried out. Most importantly, the Guidance provides a one-stop source for physical and behavioral thresholds that are used to determine noise impacts when applying for new permits. Indeed, wiping it from the books would do little more than complicate the compliance efforts of the Navy and oil and gas industry as they plan future activities, as well as NOAA’s legally-mandated environmental assessments. Yet another case of the bull in a china chop approach to governing.

UPDATE, 6/3/17: Here’s an article with some good quotes from scientists involved in creating the Technical Guidance that is being targeted.

Despite the noises coming from the Trump administration and Alaska’s elected officials, it appears that any new initiatives to expand offshore oil and gas development in the Arctic will be falling on deaf ears among fossil fuel companies.

While I was certainly glad to hear that President Obama has declared most of the Chukchi and Beaufort Seas in the Alaskan arctic “indefinitely off limits” to oil and gas development, the roar of approval from the media and environmentally-minded public was louder than the action actually merits. And the Atlantic withdrawals appear next to meaningless. I know we should never look a gift horse in the mouth, but even a quick glance reveals more gum than enamel in this one. Nonetheless, I’ll take an over-enthusiastic celebratory shout over even the fading ghost of the chance of much more enduring and disruptive roars from seismic surveys, crazy-loud engines on stabilized drilling platforms, and decades of crew transport and tanker traffic. It’s not for nothing that diverse group of scientists and activists have been calling on Obama to do just this for the past couple of years.

Still, I’m here to temper the joy. Before looking at the maps that put the modest impact of this move in perspective, there’s a red flag right up top that deserves a bit more clarification. All commenters, enviros and energy companies alike, seem to agree that this withdrawal is more consequential than the November announcement by the Department of Interior that no lease sales would be offered in either the Arctic or Atlantic for the upcoming 2017-2022 leasing period, a decision that’s won’t be finalized until July and could have been vulnerable to reversal by the incoming administration. Obama’s new declaration likely closes the door on such a rapid reconsideration of these upcoming five-year plans. But notice that the magic word in the withdrawals is “indefinitely,” not “permanently.” It seems that the door is left open to reconsideration: the White House statement detailing the withdrawal states that the “indefinitely off limits” designation is “to be reviewed every five years through a climate and marine science-based life-cycle assessment.” (To be fair, the text is somewhat ambiguous as to whether this 5-year review applies to both the US and Canadian actions, or just the latter.)

UPDATE, 1/11/17: The outgoing administration tied up a worrisome loose end this week by denying six pending applications to do exploratory seismic surveys in the Mid- and South-Atlantic planning areas. This is a one-time denial; future re-applications can be considered at any time. New surveys will be necessary to inform any future lease sales in these areas.

So for now, let’s celebrate that at least the first term of a Trump administration has its hands fairly well tied in its ambitions to expand US offshore oil production from its current focus on the Gulf of Mexico and in a 200 mile strip of waters along Alaska’s Arctic coast. Wait, what’s that? Yep, the big withdrawal announcement doesn’t remove any of the areas already being actively developed off Alaska’s northern shores (brown in this map):

The good news is that there are currently only a handful of producing wells in that brown strip, on three of the five lease areas owned by one company, Hilcorp, just offshore from Deadhorse (they’re the tiny green areas in the next map, below). In fact, out of the peak of 480 lease tracts in the Chukchi and Beaufort Seas that had been acquired by energy companies as of 2008, only 43 leases (including 53 lease blocks) are still even nominally in the planning pipeline; 42 of them are in this area that remains available to future leasing as well. Falling oil prices, disappointing test well production, and both logistical and increased regulatory hurdles have led many of the companies that were once so enthused about moving into these waters to formally abandon their leases.

Here’s a look at where things stood as recently as July 2015, when the Chukchi was still the focus of industry hopes and dreams: Read the rest of this entry »

In a second letter to the Obama administration, 28 top ocean noise and whale researchers have raised serious concerns about planned seismic surveys along the east coast of the U.S.  The scientists cite several recent studies that shed light ways that the long term health and reproductive rates of right whales have been affected by temporary stresses, and suggest that the planned seismic program could push this extremely endangered species over the edge.  With only 500 individuals remaining, the loss of each individual creates a significant impact on long term population viability.  According to the letter,

For more from the researchers involved, see this press release that includes several quotes, and for more on the maps, produced by Oceana, see this article from the Coastal Review and this page on Oceana’s website.

Shell Oil is gearing up to do the first new exploratory drilling in the Chukchi Sea off northwestern Alaska.  The project has been in the pipeline for years, and has faced numerous legal challenges (mostly regarding the danger of a spill and climate imperatives) and logistical snafus (the most extreme being a drill ship that ran aground).  Just last month, a consortium of environmental groups filed a suit challenging the most recent permits; there has yet to be a ruling.  The expansion of oil and gas development from Alaska’s north slope to offshore waters will create a marked increase in human noise in an ocean region that is currently relatively free of our intrusions.  Exploration leases have been sold in both the Chukchi Sea (left below) and Beaufort Sea (right below).

Earlier this year, the Obama administration officially put some areas in these waters off limits, but a close inspection of the maps presented then reveal that virtually none of these areas were planned for development when the above map was created in 2008; the exclusion zones appear to match the near-shore areas excluded above (one exception: a small portion of the Chukchi zone is now off-limits).

Noise concerns extend far beyond the drilling itself, or even the seismic surveys that take place prior to drilling and during the life of the project.  The drill rigs come along with a support fleet of 30 other boats and several aircraft, promising a steady din in the area.  “In the Arctic, I can’t emphasize how novel an activity this is,” says NRDC attorney Giulia Good Stefani. “It really is a whole new level of disturbance for an area already experiencing rapid change and stress.” Concerns extend from whales to walruses, seals, and polar bears.

A wide array of ongoing research is underway, aiming to characterize the current soundscape in arctic waters. Read the rest of this entry »

A letter from 75 leading bio-acoustics researchers urges President Obama to derail current plans to open much of the US eastern seaboard to oil and gas exploration and development.  Last year, the Department of Interior opened the door to new seismic surveys from Delaware to Georgia, which will clarify which areas of the continental shelf are most promising as drilling sites; these could begin as soon as this year or next.  So far, nine applications have been filed for surveys, all 50 miles or more offshore.  In January of this year, Interior announced plans to issue drilling leases beginning in 2017, with the initial five-year leasing period targeting roughly the same region (UPDATE, 3/15/16: Interior cancels lease planning); in conjunction with opening this area, development was banned in some Alaskan waters (small areas off the north slope and a larger area in SW Alaska).

 All this has spurred much public outcry, and in March an impressive array of ocean scientists from dozens of universities and research organizations around the world took the unprecedented step of sending a letter to President Obama expressing deep concern about the acoustic impacts of these plans. “The magnitude of the proposed seismic activity is likely to have significant, long-lasting and widespread impacts on the reproduction and survival of fish and marine mammal populations in the region, including the critically endangered North Atlantic right whale, of which only 500 remain,” say these researchers (see the full letter).

New dynamic maps from NOAA’s new Cetacean & Sound Mapping project indicate that these right whales use the southeast coast intensively in January and February, and are present along much of the coast in March and April moving north, and November and December heading south.  Only during the months of June-October are these whales mostly in northern waters away from the region currently being targeted.  Of course, other marine species are present year-round.

The Department of Interior suggests that since all activity will be more than 50 miles offshore, it should not interfere with commercial or recreational fishing, or near-shore areas of critical habitat; however, airgun sounds are often audible at much greater distances than that.  Energy companies also stress that heavy seismic survey activity in the Gulf of Mexico has co-existed for decades with both commercial and recreational fishing activity.

While initial push-back has largely been focused on the seismic surveys, which use pulses of loud sound to image deep below the seafloor (here’s a good explainer), the longer-term acoustic footprint of oil development is likely to also be significant. Ocean Conservation Research has been focusing on this for several years, tracking the new generation of seafloor processing facilities that are making deep-water development possible:

Much of the technology that makes deepwater drilling possible hinges on creating pre-refineries on the sea floor. These include seafloor separators, reinjection pumps, multi-phase pumps and other equipment all operating under extreme pressures and often very high (and noisy) differential pressures. Additionally these deepwater operations are typically performed from dynamically stabilized drill ships and “semi-submersible” platforms that are always churning away.

The State of New Jersey has gone to federal court to block a seismic survey planned for this month fifteen miles offshore.  The survey, funded by the National Science Foundation, received its final permits from the National Marine Fisheries Service last week; the permit (similar to those issued routinely for oil and gas exploration or Navy sonar training) allows the sound from the airguns to incidentally harass marine mammals, including the possibility of some permanent injuries.  The New Jersey Department of Environmental Protection is aiming to stop the surveys from commencing in the next week or so; they claim that this is a poor time of year to introduce potentially harmful or harassing sounds, that the surveys could disrupt local fisheries for scallop, flounder, and squid, and that the National Science Foundation should have undertaken a more comprehensive public comment and environmental assessment process.

UPDATE, 8/14/14: Mechanical issues have sidelined the survey for this summer; the National Science Foundation plans to carry out the survey next year instead, while local activists vow to push for more thorough analysis and public input.

The survey, by Columbia University’s research vessel the Marcus Langseth (left) would examine seafloor sediment, as part of research looking at how climate change has affected river runoff and deposition over the past sixty million years.  Some critics, though, seem to be conflating the purpose here with a broader initiative underway to open Atlantic waters for new seismic surveys exploring for oil and gas; those plans have stirred controversy in states up and down the eastern seaboard.

“We believe the timing of this program will be detrimental to various marine species that migrate and breed off the New Jersey coast and will negatively impact the commercial fishing industry that relies heavily on these resources,” said New Jersey DEP commissioner Bob Martin.  Similarly, Bob Schoelkopf of the Marine Mammal Stranding Center in Brigantine, was quoted as saying: “Right now, bottlenose dolphins are mating and giving birth off the coast of New Jersey. May and June are the birthing periods. They are totally dependent on their parents to provide nursing for the first two to four years of their life, and if the mother, for some reason, cannot catch fish to eat, she can’t produce milk.”  It’s not obvious from these statements whether there is another time of year that either would suggest for a survey such as this.

Meanwhile, the Asbury Park Press spoke to the project’s lead scientist, Rutgers geology professor Greg Mountain, likens the technology to medical sonograms, and says it will cap years of investigations using sea floor corings to recover ancient sediment. The goal is to understand climate and sea level changes over millions of years, information that will be critical to foreseeing future sea level change along the East Coast, Mountain says.

[Click through for more info on seismic surveys in general, and AEI’s quick take on this situation]

Read the rest of this entry »

AEI lay summary of:
Holger Klinck, Sharon L. Nieukirk, David K. Mellinger, Karolin Klinck, Haruyoshi Matsumoto, and Robert P. Dziak. Seasonal presence of cetaceans and ambient noise levels in polar waters of the North Atlantic. J. Acoust. Soc. Am. EL176, 132 (3), September 2012.

I somehow missed this study when it was published a couple years ago, but the findings are so striking that I can’t resist turning back the clock to cover it.  Researchers from Oregon State University and NOAA’s Pacific Marine Environmental Laboratory analyzed data from two hydrophones deployed for a year in some of the most remote areas of the very northern Atlantic Ocean, and found seismic survey airgun sounds to be a dominant presence, audible for 95% of each day for five months a year (and over half the hours for two more months).

Luckily for the fin whales who are the most populous marine mammal in these remote waters east of northern Greenland, they tend to show up toward the end of the summer airgun season, and concentrate their polar activity in the winter, when the airguns go silent.  But blue whales and a relatively few sperm whales like to be there in late summer, and must co-exist with the steady rumble of airgun sounds, which increase the ambient sound levels by an average of 5-10dB, and up to 20dB.  By contrast, the roar of storm-driven winter waves adds up to 12dB, and the calls of thousands of fin whales add up to 10dB.

The authors don’t speculate about the location of the seismic surveys being heard in the region, which lies well north of the Arctic Circle (the two sites are between 75 and 80 degrees north latitude; the Arctic Circle is at 66.5).  But it’s a straight, if rather long, shot from the North Sea oil fields between the UK and Scandinavia, with Norway’s offshore arctic developments a bit closer. I suspect that the offshore concentrations of red between Norway and the study sites are likely active oil fields, with heightened airgun activity; the dark red North Sea hosts one of the world’s highest concentrations of ongoing seismic surveys.

What’s especially discouraging about these findings is that this is one of the increasingly rare parts of the world’s oceans that is largely spared the scourge of shipping noise.  The more northern site lies close to a minor shipping lane between Norway and its remote arctic island outposts, but compared to the din of ships in most of the temperate latitudes (where shipping noise has roughly doubled in intensity each decade since the 1950s), this should be—or could—be an acoustic refuge. The map to the right shows the study areas, on the sparse fringes of the red cloud of global shipping routes. (Ed. note: Fish, which are not as wide-ranging as whales, and often use low-frequency sounds, are also likely affected by the increased background noise caused by airguns.)

The whales who visit seasonally seem to be putting up with the additional noise from seismic surveys; hundreds of blue whales are heard during 60-80% of hours in August and September, even as airguns continue to be heard nearly 100% of hours; the newly-arriving fin whales are heard close to half the time in those months, increasing to 70-80% of hours as their numbers climb to an estimated 6000 in mid-winter. Of course, at close range the whale calls are much louder than the distant airguns; but the steady hum of airguns at 5-10dB above what would otherwise be the background sound level can make it difficult for whales to hear their brethren across the dozens or hundreds of miles that they might otherwise communicate. As the authors note: “(D)uring the summer months. . . reverberation effects associated with the propagation of airgun signals often caused a continuous series of transient sounds.” 

The authors note that recordings made in the early 1970s show winter-time sound levels similar to those recorded in this study; that study, however, did not find the summertime increase that is now associated with the distant seismic surveys.

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.

One 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.”

She 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.

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.  

For 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.”

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.

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.  

And, 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.

“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.

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

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

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!

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.”

In 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.

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.

I’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).

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.

Two 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.

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.

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.

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 »

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…