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.

A fascinating new study provides the first direct evidence that shipping noise may increase stress levels in whales.  During the days after the World Trade Center attacks, global shipping was halted; a team of researchers studying right whales in the Bay of Fundy decided to go ahead and continue collecting fecal samples, and were struck by how peaceful it was: Rosalind Rolland recalls that day and those following were like a primal ocean scene, “There was nobody out there except for us and the whales.”

In 2009, Rolland realized that another researcher, Susan Parks, had recordings of noise levels for the days before and after 9/11, and so they joined forces to see whether the samples taken from whales on those days showed any changes in stress levels (fecal matter contains stress hormones that can be measured).  As it turns out, the days after 9/11 mark the only time during Rolland’s five-year study that stress hormone levels were markedly lower than the overall average, and corresponded to a dramatic reduction in noise, especially low-frequency noise.

““This is what many of us had been looking for,” said Christopher Clark, director of the bioacoustics research program at the Cornell Lab of Ornithology, who was not a paper co-author. ”Here is the first solid piece of evidence that says there’s a link between noise level and stress.” Clark noted stress has long been tied to longevity, reproduction, disease and other key health indicators in whales. Researchers have long speculated that noise could be a stressor for ocean creatures, but there is no practical way to test a correlation, since ocean noise is nearly omnipresent in most areas.

The fact that this is an opportunistic study does mean that it’s unlikely to be considered solid proof, or to influence ocean noise policy.   As Dr. Rolland noted, ”These are after all 50 tonne animals so they don’t make terribly easy things to study…Past studies have shown they alter their vocalisation pattern in a noisy environment just like we would in a cocktail party, but this is the first time the stress has been documented physiologically.”

Dr. Ian Boyd of the University of St. Andrews in Scotland, home to many top ocean noise researchers expressed uncertainty that such a short time period and small sample “shows what is claimed.”  Boyd is one of a group of researchers advocating for a Quiet Ocean Experiment, in which large portions of ocean would be quieted for brief periods, allowing for more comprehensive studies of animal behavior and physiology before, during, and after the experimental periods.  To implement this idea, global shipping routes would need to be shifted for the duration of the experiment.

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.

For the first time, an onshore wind farm has triggered calls for caution from marine mammal protection organizations.  The 2500-acre, 56-turbine wind farm will be built along a steep shoreline that funnels nutrient-rich waters from Antarctica to the surface, spawning a dense aggregation of phytoplankton and krill. Along the coast of Isla Grande de Chiloé, blue whales and right whales gather from January to April to feast on this abundance; blues come as close as 400m to shore, and rights have been seen only 5m offshore.

Environmentalists, including local organizations like Santiago’s Centro de Conservación Cetacea, and international voices such as the Whale and Dolphin Conservation Society have raised dual concerns, regarding construction of a new port to bring construction materials to the site, vastly increasing ocean noise from ship engines in this relatively acoustically pristine area, and possible disturbance or even displacement of animals due to noise from pile driving during construction and airborne wind turbine noise during operations. Even the International Whaling Commission’s scientific committee has called for ”the urgent development of an environmental impact assessment in this region and to reconsider locating the wind farm towers further away from coastline.”

The importance of the feeding ground to southern hemisphere blue whales, combined with having 40% of the turbines right along the shore, raise the question of whether the ongoing blade noise will keep whales at a distance; there is some evidence that airplane overflights cause whales to move away, and the sound levels of the turbines will be similar to a small plane. Whether whales might be able to move a small distance away and still find enough krill is the big question. Chile’s environmental authorities approved the project in August after requiring a simple environmental declaration, rather than a detailed impact study; the Chilean Supreme Court is hearing a lawsuit from opposing groups, and will make a decision in the next few months.

National Geographic News has a good, detailed article on these questions.

Here’s a great fifteen-minute radio feature from Voice of America that digs into the issue of shipping noise and its effects on ocean life.  It features Michael Jasny of NRDC, recordings of shipping noise off Vancouver Island, NOAA’s Michael Bahtiarian on their quiet research ships, and Kathy Metcalf of the Chamber of Shipping of America.

Give a listen!

(transcript also included at that page link)

Five environmental organizations have filed a legal petition asking NOAA to enforce speed limits in National Marine Sanctuaries off the California coast. If NOAA does not take action within a year, the groups say they may sue to under the Marine Mammal Protection Act. “Our marine sanctuaries should be a safe harbor for marine life, but instead whales in California are at constant risk of being run over by big ships,” said Miyoko Sakashita, oceans director at the Center for Biological Diversity. “Mandatory speed limits for ships traveling through our marine sanctuaries will save whales and clean our air.” Slower ship speeds also significantly reduce a ship’s noise, which could be a welcome relief in such a heavily trafficked area.

In the past decade, nearly 50 large whales off California have been struck by ships. Last year, at least six were killed in collisions. A key factor in the decision about lowering ship speeds is likely to be whether the loss of less than ten whales a year warrants the change (more whales may be struck and sink without being seen).  Along portions of the East Coast, federal authorities have imposed a 10-knot speed limit for ships 65 feet or longer for the past several years in order to protect the North Atlantic right whale, which is critically endangered, numbering only around 300 animals, so the loss of any individual is a blow to the population’s future.

The groups are advocating a similar mandatory speed limit of 10 knots (about 11 mph) for all ships larger than 65 feet while sailing through California’s four national marine sanctuaries, which stretch from the Marin Headlands north of San Francisco, 300 miles down the coast to the Channel Islands north of Los Angeles.  Ship speeds are now usually 13-25 knots. Since 2007, when four blue whales were struck by ships near the Channel Islands National Marine Sanctuary, NOAA has issued seasonal bulletins urging a 10 knot speed limit from May-December, when the blues are most numerous; environmental groups say most ships ignore this voluntary advisory, while shipping groups say most ships do adhere to it.

Two years after proposing changes in whale-watching rules  in Puget Sound to protect endangered orca populations, NOAA has finalized its new standards.  Boats will need to stay twice as far from the whales (200 yards), and a half-mile wide “no-go” zone has been established along the entire west coast of San Juan Island, an important feeding zone.

For detailed coverage of the new plans, see these earlier AEInews posts.

UPDATE, 4/15: Canadian regulations lag those on the US side of the border; a recent study found that an average of about 20 boats surround orcas in summer months in one popular whale-watching area.  See this recent article that summarizes a set of proposed regulations developed by the University of Victoria (BC) Environmental Law Clinic, including 500 meter approach limits, 30 minute time limits, and weekly “days of rest” with no whale watching boats in the water.

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…

A new study reveals yet another family of ocean life previously thought to be deaf actually use sound to avoid potentially dangerous areas.  It’s the latest fascinating study from a collaboration between British and Australian scientists that has been revolutionizing our understanding of the role of acoustic ecology in reef habitats. In this study, crustaceans that feed on plankton avoided reef sounds; such reefs are home to fish that would enjoy a crustacean lunch.

Many such small crustaceans are foundations of vast ocean food webs. Co-author Dr Andy Radford, who is leading a major project in Bristol to investigate the impact of anthropogenic noise on marine animals, said: “This highlights just how damaging the impacts of human noise pollution may be for so many different creatures.  Chronic noise from shipping, drilling and mining may mask crucial natural sounds, causing animals to make poor or even fatal decisions, which in turn will threaten vital fisheries and tourism resources.”

Coral reefs are noisy places, and this noise can be an important cue for animal orientation. Dr. Steve Simpson is quoted in a University of Bristol press release: “The combination of clicks, pops, chirps and scrapes produced by resident fish, snapping shrimp, lobsters and urchins can be detected with our hydrophones from many kilometres away.  Our research has already found that reef noise is used by the larvae of fish and even corals to locate and select habitat after their early development in the open ocean, but using noise to avoid reefs, that is a first.”

The mechanism of hearing in these tiny creatures is poorly understood, although co-author Dr Andrew Jeffs and his group from the University of Auckland have found that both tropical and temperate water crabs and lobsters are attracted by the noise of their adult habitat.  Dr Jeffs said: “It is clear that some crustaceans use sounds for orientation, and that noise can induce a downward-swimming response. But this study throws wide open our understanding of crustacean hearing, and much more research is now needed to understand how and what these little critters can hear.”

Seven years after the Southern resident killer whale population in Puget Sound was declared endangered, US government regulators appear poised to finally enact new regulations to protect orcas from boat noise in key foraging areas. In 2009, NOAA proposed increasing the minimum buffer that boats must give orcas, from 100 yards to 200 yards, and creating a half-mile “no go” zone along the entire west side of San Juan Island, where orcas gather to feed.  After extending the comment period into early 2010, finally – a year later – NOAA’s National Marine Fisheries Service has formally completed its analysis process; now, the Department of Commerce and Office of Management and Budget must OK the plan before the new rules go into effect, hopefully before this summer’s whalewatching season.

Reducing boat noise is a key piece of the puzzle for orca health.  Several recent research projects have identified impacts of boat noise, including reducing foraging time and interfering with communication.  The primary direct cause of orca decline is malnutrition as salmon runs decline; for this reason, it’s crucial that orcas are not impeded by boat noise as they seek out the fewer salmon that remain.

Seattle’s Q13 Fox News has covered the story well in recent months, including a recent update, along with a three part series that ran in November 2010 (all four stories have video components).

On the Canadian side of the border, things are moving even more slowly.  In December, a Canadian court ruled that the Canadian government’s approach, which uses voluntary guidelines, is not sufficient in dealing with an endangered species.  But Canadian officials have appealed that ruling, and it appears that nothing will change for the foreseeable future.

“It’s another season where we’re allowing more stress to be put on these animals.  You have to start asking how much more they can take?  If you ask anyone, a politician anybody about the Orca they would say they’re wonderful and beautiful and magnificent.  Why is it we can’t turn that into action?” asks Christine Wilhelmson of the Georgia Strait Alliance.

Follow this link for all previous AEI News coverage of orca issues.

Orca populations around Vancouver Island won a decisive victory in Canadian Federal Court this week, as Judge James Russell ruled that the Canadian government cannot rely on voluntary protocols and guidelines to protect orca critical habitat.  The judge brought acoustics into his decision by stressing  that critical habitat protections must include ecosystem features, including prey availability and and noise impacts.

The decision, which is detailed in this article from the Vancouver Sun, could push the Canadian government toward some difficult decisions, especially regarding salmon harvests.  Declining salmon runs are a key factor in orca declines, and there is a push to limit fishing to assure that orcas (and other wildlife) have more access to this key prey species.  In addition, research continues to suggest that shipping noise may interfere with orca communication and foraging (recent AEI post); there’s no telling how this conflict might be resolved.

The VENUS ocean observatory network is clarifying the degree to which waters around Vancouver Island are infused with the shipping noise.  The data is reinforcing concerns that local orcas and other sea creatures are likely to experience several negative impacts, including chronic stress, the need to use more energy to talk louder, and perhaps interference in foraging. A good article in the Vancouver Island-based Times-Courier (excerpted below) details the findings.

“The noise is virtually continuous during daylight hours and quietens a little bit overnight,” Richard Dewey, associate research director on the University of Victoria’s VENUS (Victoria Experimental Network Under the Sea) project, said. ”In addition to the annoyance of the constant din, [the whales] are likely to have to shout over the engine sounds and listen through the racket to pick out and identify the messages.” Tricky tasks, such as the use of broadband clicks to echo-locate fish — the sole diet for resident killer whales — is likely to be extremely difficult when boats and ships are nearby, Dewey said.

It was expected the Strait of Georgia would be noisy as it is one of the busiest shipping lanes in the world, but among recent changes is the increase in massive container freighters. ”They travel at twice the speed that vessels used to travel at, they use four times as much energy and make four times as much noise in the ocean,” Dewey said.

One of the — as yet unanswered — research questions is whether the whales can survive increasing noise at the same time as they are coping with shrinking salmon runs and climate change. ”Whether the whales and dolphins can adapt is an open question,” Dewey said.

Learn more at the VENUS website.

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

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

In Puget Sound, the vulnerable population of 85 resident orcas face a daily onslaught of boat noise, from fishermen, commercial whale watching, and recreational watercraft.  Current voluntary guidelines call for boats to remain 100 yards away, and to slow to seven knots when within 400 yards.  ”People don’t always grasp what 100 yards is,” said Kari Koski, program director for Soundwatch, a project of the local Friday Harbor Whale Museum. “We try to educate them and give boaters the opportunity to make the right decision.” Soundwatch teams that flag down boaters who are too close, or going too fast, find that many local boaters are unaware of the voluntary guidelines, or simply don’t notice the whales nearby.  An article this week in the Seattle Times provides a great overview of the on-water education undertaken by Soundwatch, as well as NOAA’s plans for more stringent mandatory rules, which are planned to go into effect next year.  NOAA’s proposal calls for 200 yard limits, as well as setting aside the entire west side of San Juan Island as a “no-go” zone for all boats, including kayaks, out to a half mile from shore.  The proposal was released in 2009, with comments accepted into early 2010, and a final decision expected sometime soon.  See this earlier AIEnews post for more on the proposal, and reactions from locals; this earlier post looks at some of the research underway to assess the effects of boat noise on orca communication (it makes them call louder) and foraging (it may cause them to expend more energy finding food).

Using the same recording units that have provided a rich stream of new data on the effects of shipping noise on whale communication off Boston, Chris Clark of Cornell is spearheading a new project to study the acoustic ecology of the Gulf of Mexico.  According to a press release from Cornell:

“The team will anchor 22 marine autonomous recording units (MARUs) to the sea floor in an arc stretching from Texas to western Florida, along the edge of the continental shelf. These units will record underwater sounds for three months before they receive a signal to let go of their tethers and pop to the surface for retrieval. After analyzing the data, the team will deliver a report to NOAA and other agencies involved in the oil leak response. The MARUs will listen for endangered sperm whales and a small population of Bryde’s (BRU-des) whales. They will also pick up sounds of fish and ship traffic. Some devices will be placed in areas apparently unaffected by the oil to collect “control” site information; others will be close to the gushing well. The goal is to document the state of the sounds in the ecosystem over an extended period of time and compare them with known information of the oil spill.

Researchers deploy recording units (Photo: Danielle Cholewiak, BRP)

“This will be the first large-scale, long-term, acoustic monitoring survey in the Gulf of Mexico,” Clark said. “We can provide one more layer of understanding about this ecosystem, using sound to measure animal occurrences, distributions and communication, as well as background noise levels from shipping and weather, and perhaps visualize how these features are being influenced by the oil. The whales are like oversized canaries in the coal mine — they reflect the health of the environment they live in.”

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

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

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

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

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

This good news is courtesy of Brandon Southall’s SEAblog:

DNV, a Norwegian-based company that develops classification-specific standards for the construction of vessels, has released the first industry standard for reducing underwater noise for commercial vessels.  While not targetted at the largest cargo ships and tankers necessarily, this is a notable development within the commercial shipping industry regarding noise impacts on marine life.  A press release from DNV, which notes the ongoing effort within the International Maritime Organization’s Marine Environment Protection Committee on this issue, may be found at: http://www.dnv.com/news_events/news/2009/dnvsilentnotationmakessomenoise.asp

I’d just add that the company’s press release notes that DNV “will offer sound radiation evaluation services and recommendations on hull, propulsion and engine design to reduce noise.”

I’ve just finished reading what must be the most exciting research paper I’ve seen this year, barely nudging out a similar paper addressing terrestrial noise impacts. A small group of researchers, with Chris Clark of Cornell as the lead author, took a giant step forward in addressing the impacts of ocean noise on the communication ranges of whales.  They came up with a clear and strikingly rigorous set of new metrics that will allow researchers and ocean planners to have a much more practical picture of how numerous noise sources combine to create cumulative impacts on acoustic habitat.  The new approach centers on the “Communication Space” of individual animals, as well as groups, and provides an intuitively obvious way to both imagine and assess the effects of ocean noise – measuring the area in which an animal can hear or be heard by others of its species.

My formal “lay summary” of this paper is reprinted in full below the fold, and I encourage anyone with a deep interest in ocean noise to read through that five-paragraph overview, or to download the paper yourself.  The key takeaway for those of you with a more casual interest in these issues is that in the test case that they used to illustrate their new approach, the researchers found that shipping noise has dramatically different impacts on different species, even though all three species they studied are low-frequency communicators.  In the area off Boston Harbor that they investigated, the critically endangered right whale is by far the most affected by shipping noise: on a day when two ships passed through the area (the average is often six), right whale Communication Space was reduced by an average of 84% over the course of the day, with several hours in which they could hear and be heard in an area less then 10% of that which would be expected without shipping nearby. Since right whales call back and forth to find each other as they form groups for feeding, this is truly worrying (though the key question of how a reduced communication range actually affects animals remains unanswered).  Fin whales and humpbacks were far less dramatically affected, with their Communication Spaces reduced by just 33% and 11% respectively.

These first examples focus on the effects of low-frequency shipping noise on low-frequency communication by large whales, but this approach can easily be used to address mid- or high-frequency noise sources (sonars, airguns) and higher frequency animal sounds such as those used for echolocation, opening a vast and exceedingly useful new doorway for biologists and ocean managers, as well as the general public, to appreciate the impacts of human sounds in the sea.   (click through for complete lay summary)

Read the rest of this entry »

NOAA has released its proposed critical habitat for the endangered Cooks Inlet beluga population: it includes the entire upper part of the inlet (which includes Anchorage and Wasilla), and a coastal stretch of the lower part of the inlet as well.  This isolated population of belugas experienced a population crash in the 1980’s which is widely blamed on over-harvesting by native subsistence hunters, but has not recovered since the hunting was limited.  Pollution, limited salmon runs, and noise are all considered likely factors in the population’s struggle to survive.  Over the past few years, it has become apparent from field research studies and monitoring around seismic surveys that belugas are among the more sensitive cetacean species to sound; they tend to avoid noise sources at greater distances than most other whales, often tens of kilometers.

According to the Anchorage Daily News, NOAA officials said the proposed rule and the prior listing of belugas could trigger some changes to major development projects over the next decade — seismic drilling for offshore oil and gas, and a dock for the Chuitna coal strip-mine proposed on the west side of Cook Inlet, for example, the agency said.  NOAA said it doesn’t anticipate the stepped-up scrutiny will result in rejection of energy projects in the Inlet. The rule would require other federal agencies to consult with the federal fisheries service before approving projects in the proposed critical habitat areas. Ongoing construction at the Port of Anchorage, planned to continue for several more years, includes monitoring for belugas that may be close enough to be seriously disturbed, though the Port Director said they will be submitting comments on the proposed designation.

UPDATE: Public comments on the critical habitat designation have been extended to March 2010. A NOAA biologist assured locals attending a public meeting that the new designation would not add “onerous” oversight.

(this item appeared recently on AEI’s lay summary of new research page)
Reeder, Chiu. Ocean acidification and its impact on ocean noise level: An analysis using empirical and physical models of acoustic transmission loss. Presented at ASA October 2009 meeting.

Udovydchenkov, Duda. Ocean noise level change in response to ocean acidification. Presented at ASA October 2009.

These two papers take a closer look at the widely-noted ocean noise implications of increasing ocean acidification (a combination of factors related to global warming is triggering a steady increase in the ocean’s pH, which decreases sound absorption). When the acidification results were first released there was much speculation that shipping noise would propagate farther, resulting in cumulative ambient noise increases throughout the oceans. These two papers, presented at this fall’s Acoustical Society of America meeting, both come to the same conclusion: low frequency noise will not be significantly increased due to ocean acidification; rather, the primary changes will occur at mid-frequencies. This calms concerns about shipping noise, but may (over time) lead to slightly larger areas being impacted by mid-frequency active sonar, some acoustic harassment devices used by fish farms, noise from recreational boating, and other mid-frequency noise.

Rather than simply looking at the effects of sound absorption Read the rest of this entry »

Ongoing research by NOAA’s Northwest Fisheries Science Center continues to look more deeply into the effects of boat noise on Puget Sound orcas.  The research team, led by Marla Holt, had previously found that orca calls increase in volume in step with background boat noise: for each decibel of added background noise, their calls also got a decibel louder.  In their latest round of research, the team is trying to determine whether the background noise is diminishing their foraging success due to masking (drowning out) some of the critical group communication, and whether calling louder makes the animals use more energy.

Image courtesy National Geographic

A 20% population decline among the Southern Resident orcas during the late 1990’s has been attributed to a combination of fewer salmon, toxins, and vessel noise. According to a recent article on National Geographic.com, Holt, who will present the team’s preliminary findings in October at the Biennial Conference on the Biology of Marine Mammal in Quebec, said that their research indicates killer whale communication is particularly important during hunting. What’s more, previous studies in birds had suggested that the animals consume more oxygen to raise their voices above ambient noise, making their metabolic rates spike and burning up stored energy, Holt said, adding that it’s possible the same phenomenon could be occurring with killer whales, although it’s too early to know for sure.

NOAA’s recovery efforts for the orcas include new regulations that will keep whale-watching vessels 200 yards from orcas, as well as efforts to reduce toxin pollution and to restore salmon runs.  Longtime orca researcher Ken Balcomb feels it all comes down to the decline in salmon: ”If you deny them the food, [there's] basically no point in worrying about other factors,” Balcomb said. He calls the whale-watching limits “feel-good thing,” adding that “my observations over 35 years [are] that [whales] don’t really get disturbed by anything, much less vessels.”  Holt acknowledges the limits of the new regs, saying that ”a lot of people would argue, Why focus on these vessel regulations? But it’s one thing we can do immediately.”  It appears to AEI that the question is not really whether the boat noise disturbs the orcas, but whether it may drown out parts of their foraging communication, making it more difficult for them to find and eat the few salmon that do remain available to them.  And, given their tenuous situation, if they are forced to use more energy to call during hunting, their overall health is likely to be at least somewhat affected.  Moreso, each time that a particular foraging attempt is aborted due to a noise intrusion, a larger bit of the daily energy budget has gone to waste.  Time will tell whether the new boat limits actually lower the received sound levels for foraging whales; if so, it’s a step in the right direction.

A report commissioned by the International Fund for Animal Welfare (IFAW), and submitted in July to the International Maritime Organization’s Marine Environmental Protection Committee, provides a detailed assessment of the prospects for using ship-quieting technologies to reduce the level of background noise in the world’s oceans.  According to the report, which cites a wide array of recent research, similar types of ships can vary in their sound emissions by 30-40dB; some engineering experts suggest that the noisiest of these could reduce the primary source of noise (propellor cavitation) by 10dB.  The report, Reducing Underwater Noise Pollution from Large Commercial Vessels, by Dr. Marin Retilson, is available for download on the IFAW website. ”The noisiest 10% of ships account for between 50% and 90% of the noise pollution and it is these vessels that are most likely to benefit from relatively minor modifications to reduce propeller noise,” said Russell Leaper, an IFAW scientist.  The report summarizes technical approaches to reducing ship noise, with an emphasis on utilizing modern propeller design, along with fins and ducts to improve wake flow, which could reduce noise output from the noisiest ships and be cost effective. There is a relatively poor understanding of noise output from large commercial vessels and the next step is to  do more wide-reaching assessments of individual ship noise, in order to identify the vessels that could make the most difference in reducing ocean noise levels.

A target of a 3dB reduction (i.e. halving the acoustic energy) in 10 years in ocean noise was suggested at an International Workshop on Shipping Noise and Marine Mammals held in Hamburg in April 2008. This target has been endorsed by the Scientific Committee of the International Whaling Commission. You can download the Hamburg workshop report here.

From AEI’s lay summaries of key science and policy:

A comprehensive report on Mediterranean shipping from the International Union for the Conservation of Nature and Natural Resources includes a long section in the early pages on noise impacts. Due to the concentration of shipping in the Mediterranean, ambient noise is 40dB higher than in relatively shipping-free regions such as the Sea of Cortez. Among the recommendations are that “Much effort should be devoted to developing a legal framework within which underwater noise is recognized and regulated as a threat,” and the advocacy of MPAs that are designed to provide acoustic protection to critical and productive habitats, where “noise levels should not be allowed to exceed ambient by more than a given value, including noise from sources located outside the MPA.” In addition, the report stresses the importance of moving rapidly to develop regional hydrophone networks with which to monitor noise and develop current “noise budgets,” as well as the need for expanded research using new non-invasive methods to examine hearing sensitivity and changes due to noise exposure in wild animals, and analysis of stress hormones in response to noise. The authors of the report forge important new ground as they summarize: “In addition to defining which impacts should be avoided or mitigated, we also need to draw up a model of ‘acoustic comfort’ that we should guarantee to animals, at least over sufficiently extensive protected areas. This is a novel concept. It means we should define the (near to) zero-impact noise level that a habitat should have for each type of marine life.”

Ameer Abdulla, Olof London (editors). 2008. Maritime traffic effects on biodiversity in the Mediterranean Sea: Review of impacts, priority areas and mitigation measures. Malaga, Spain: IUCN Centre for Mediterranean Cooperation. 184 pp. [DOWNLOAD(pdf)] [WEBSITE]

Conservationist fears that the end is neigh for the decades-long moratorium on oil and gas exploration off most of America’s coastlines were ratcheted up this month by the passage of the American Clean Energy Leadership Act in the Senate Energy and Natural Resources Committee.  While Senate Democrats highlight the alternative energy elements in the bill, the oil and gas industry is clearly focused on the openings for new offshore development that it contains. The bill now moves to the full Senate for consideration; floor action has not yet been scheduled. The bill contains lots of eco-good stuff (including a ban on US import of Canadian oil sands product), along with the long-dreaded “inventory” of the Outer Continental Shelf’s oil and gas potential.  For much of the US east coast, no modern seismic surveys have taken place; what data exists is largely from the 1970’s, at much lower resolution than is now possible.  There are many steps between this bill and any actual offshore oil development (even if it passes the House and Senate with the OCS survey provision in place, there is still a need for funding for the surveys, and a full Programmatic Environmental Impact Statement process that has yet to begin), but for an increasingly vocal contingent of activists, the proposed seismic surveys will be a line in the sand.  AEI certainly shares the concerns of many others about the effects of survey noise on wildlife (see this recent AEI presentation to a Canadian government advisory meeting, focusing on questions about surveys disrupting foraging activity).  Six different geophysical contractors have proposed seismic surveys off the Atlantic coast; the Minerals Management Service Atlantic Seismic PEIS website has links to maps of these proposals, which span most of the east coast and include a huge amount of overlap.  At the very least, data sharing should be required, in order to minimize duplication of this extremely noisy activity.

However, it is also worth noting that the OCS inventory that is called for in the current Senate bill includes not just oil and gas resources, but also an assessment of potential for wind, wave, and other alternative energy development, fisheries, habitat and conservation, and military use.  I am particularly struck by the provision to assess habitat and conservation values in the OCS: this is exactly the sort of regional overview that could provide the data needed to do real ecosystem-based management of all offshore activities.  Such a comprehensive assessment would identify key habitat (seasonal or permanent) that needs protection from military training activities and increased shipping, including LNG terminals.  The fisheries inventory could also serve to constrain the extent of seismic survey activity, especially for fisheries with depleted stocks and active fishermen associations (both of which are widespread on the east coast).  It may still be possible to strike the whole idea of further oil and gas development from the energy bill; we may be close to the societal tipping point where we are ready to acknowledge that new sources of CO2 simply cannot be tolerated.  The Chairman of the House Natural Resources committee, Nick Rahall, points out that “even the American Petroleum Institute’s most optimistic projections - a best-case scenario extrapolation, requiring that the entire OCS be made available - would, in 2030, provide no more than 5% of our total daily energy needs, and displace only 8% of our oil imports. These are large volumes of oil, to be sure, but they comprise less than half the impact of the increase in fuel efficiency standards that Congress passed just over a year ago.”  Rahall’s committee has held three hearings on oil development in the OCS, and is the gateway for House consideration of a companion to the bill now moving through the Senate. Still, it may not be politically feasible to preclude OCS development outright at this point.  The potential for a comprehensive inventory of offshore resources, including habitat, conservation, and fisheries, may turn out to be well worth the trade-off of allowing the idea of seismic surveys to stay alive for a bit longer.  It’s highly likely that the results of any such comprehensive inventory will constrain survey operations, perhaps even to the point that the industry itself finds the oil and gas horizons too limited to be worth pursuing.