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.