A fascinating new study sheds light on changing stress levels in baleen whales over the course of the past 150 years.  Earwax from fin, humpback, and blue whales accumulates over their lifetimes, a bit like tree rings, and the researchers were able to track cortisol levels by sampling the layers in earwax plugs from museum collections.  This study averaged the results from 20 whales; the researchers are now beginning their analysis of over a hundred new samples.

The takeaway is pretty striking: stress levels track well with increasing whaling activity through the early and mid 20th century (blue line below), and dropped dramatically when commercial whaling ended.  In the midst of that span, a lull in whaling was countered by military actions durring WWII, which seems associated with a smaller spike in stress.  And while stress remained low from the 70s through the 90s, it appears to be rising again in the past couple of decades; the researchers suggest that rising sea temperatures are the most closely associated factor in this recent spike, with other anthropogenic factors including shipping noise also likely contributing.

A couple of caveats are in order. Most importantly, this study had only 6 earwax samples that extended past the year 2000, so recent trends may be distorted by the small sample size; the spike in 1995-2000 represents just four whales, and the final plot points include two fin whales that lived only a couple of years (interestingly, their stress loads were low, so the recent dip may be particularly uncertain).

Not surprisingly, there were notable differences between species and a marked variability over the course of individual whales’ lives that did not track with global trends in nearly so striking a way.  Here is a particular whale that suggests increased stress in particular years (including a possible WWII encounter), but which appears less affected by the global whaling trends, perhaps reflecting where it lived:

All this is really quite exciting, though.  We can look forward to much more robust results as this sort of analysis is expanded to more whales, and to other hormonal markers. It’s also possible that as samples from whales that died more recently are included, regional trends related to increased shipping noise may begin to become apparent.  At the same time, this is a good reminder that as much as we like to focus on acoustic factors, the stressors affecting modern whale populations are many, with climate and prey availability being especially pronounced.

Last fall’s innovative 2-month voluntary slow-down of ships traveling to and from the Port of Vancouver was successful on one count—average overall shipping noise was reduced by 44%—but a stark absence of the normally abundant resident orcas stymied the equally important second line of inquiry: how would reducing the noise level, but spreading more moderate noise over longer time periods, affect orca behavior?

About 60 percent of the ships transiting Haro Strait complied with the voluntary speed restrictions; even this level of participation succeeded in reducing the overall level of ship noise by 2.5 decibels, very close to the 3dB target set by the International Whaling Commission a decade ago. Thanks to the logarithmic scale of decibel measurements, a 3dB reduction amounts to cutting the sound energy in half. This is great news, a real-world confirmation that the noise of global shipping can be reduced relatively easily—albeit by increasing transit time.

It’s this element that marine mammal experts remain uncertain about. Slower ships remain audible for longer during their passage, though at a lower volume; perhaps worse, the quiet periods between the passage of large ships became notably shorter and noisier, thanks to the lingering presence of ships in the mid-distance. What is more livable: a constant lower noise level or trading off louder periods for interims with relatively little noise? As researcher Scott Veirs notes. “I’m not sure which I would prefer, but we definitely don’t know which the whales prefer.”

An excellent in-depth article on the Seattle nonprofit news site Crosscut tells the tale of the researchers waiting on shore to monitor whale behavior. But rather than seeing whales on most days, there were no orcas at all during the first month of the slowdown, and only six appearances in the second month. A stark lack of salmon kept the orcas out of the area; salmon shortages are the primary factor driving the decline in the Southern Resident orca population. A recent modeling study by a diverse group of researchers suggested that increasing salmon numbers by 15% while also reducing shipping noise by half would allow the resident population to recover. (The decrease in salmon numbers is compounded by a boom in populations of seals and sea lions, who also eat salmon.)

The Crosscut piece zeroes in on the questions facing British Columbia, where new oil and gas ports and expansion of existing pipelines could add even more ships to the mix:

Piloting his 31-foot research boat Wishart back to Seattle from the San Juan Island study site, Rob Williams mused on his 20 years studying killer whales. “A whole lot of science has been done already,” he said. It may be time to start making some  difficult policy decisions about vessel noise, Williams said, and that means weighing safety issues and economic tradeoffs alongside concern for the whales. A number of factors, including the Canadian government’s approval of Kinder Morgan’s pipeline to export oil to Asia, could drive future increases in Port of Vancouver vessel traffic.

“What we have to do next is to have some really uncomfortable conversations. . .about how much of this acoustic space do we think it is fair to ask the whales to give up.” Williams said. “And how much are we willing to give up to have killer whales persist?”

“And those aren’t science questions,” he continued. “They are really tough value judgments.”

The burgeoning field of soundscape ecology (also dubbed ecoacoustics) is poised to take a remarkable leap forward during the just-beginning Australian summer  of 2018.  By mid-year, researchers plan to install 400 microphones in 100 locations spanning the continent’s seven diverse ecoregions.

At each location in this Australian Acoustic Observatory (A20), two acoustic recorders will be placed in relatively wet habitats for that biome (wetland, river, creek, drainage, depression) and two in relatively dry areas. Every six months or so, researchers will swap out the SD cards at each location and upload all the files to the project website, where everyone can engage with this extraordinary dataset.

David Watson, one of the Chief Investigators, noted in an introductory article:

One of the strengths of this project is our ability to use sound to picture time. We can prepare fascinating visualisations that contain months’ worth of data in a single image.

Some of the effects we’re measuring, such as the impact of cane toads and other invasive species, have very obvious acoustic signatures. They are dramatic to hear, but even more striking to see in a sonograph (essentially a graph of sound).

We’ve pioneered the use of false-colour spectrograms to visualise long duration recordings. These make clear the flattening effect of invasive species, or the long-term subtle shifts caused by climate change.

You absolutely want to check out those two links he provides! The first is to a short article containing an interactive 24-hr spectrogram which plays several minutes from each of three different times of day; the second is a thorough project description that was shared at conferences when they were in the pilot phase last year, and includes a deeper look at their innovative approach to spectrograms and the types of information they expect to glean in various habitats. It all promises to be a fascinating and exciting step forward for soundscape ecology.

They look small, about the size of a “cherry bomb” firecracker.  They’re legal, exempt from the Marine Mammal Protection Act thanks to their functional purpose: protecting fishermen’s nets from seals and cetaceans poaching their catches, including squid, anchovies, and tuna.

But they are loud and used freely in waters off southern California. Divers report physical pressure waves hitting them from up to a mile away; they’re audible in the water out to tens of kilometers and have been recorded by Scripps Acoustic Ecology Laboratory hydrophones 37,000 times a month at peak fishing season—up to 500 blasts an hour at times.

A recent article in Hakai Magazine delves into this little-known ocean noise issue. “The amount of use is alarming,” says Scripp’s Simone Baumann-Pickering. “We know the noise poses a potential threat.”  While earlier NOAA research with dolphin carcasses demonstrated they can cause physical damage at extremely close range (less than a meter), the Scripps team did not document any physical injuries, though they stress that behavioral impacts are likely.  Divers and whale watch captains confirm that whales tend to avoid areas where the seal-bombs are in use; yet fishermen counter with reports of dolphins and whales being unfazed by their use (keeping the uncertainty cycle spinning, conservationists speculate that such non-response could be related to deafness from previous exposure to this or other loud noise).

In an effort to move beyond the conflicting anecdotal report, the Scripps researchers are now looking more closely at the effects of the noise on Risso’s dolphins, a squid-loving species that is commonly exposed. As Baumann-Pickering affirms, “In science, you have to measure the effects.”

Note: Hakai Magazine, published by a foundation in British Columbia, is well worth being on the radar of any ocean lover.

Lay summary of:
Noise pollution is pervasive in U.S. protected areas. Rachel T. Buxton, Megan F. McKenna, Daniel Mennitt, Kurt Fristrup, Kevin Crooks, Lisa Angeloni and George Wittemyer (May 4, 2017). Science 356 (6337), 531-533. [doi: 10.1126/science.aah4783] Online access (subscription)

Ongoing data analysis by researchers from the National Park Service and Colorado State University is revealing an increasingly detailed picture of the sprawling impact of human noise in protected areas around the United States. The most recent paper from this groundbreaking team digs into the sound models to offer a better sense of how extensive the issue is, and highlights the promise of focusing conservation efforts on preserving areas where the human noise footprint remains small.

The researchers zero in on two key thresholds of noise: 3dB above the natural ambient sound, which marks a doubling of noise levels (causing a 50% reduction in the area over which sounds can be heard), and 10dB of excess noise, which is a 10-fold increase, leading to a 90% reduction in listening area. As the authors note, these are “levels known to interfere with human visitor experience and disrupt wildlife behavior, fitness, and community composition.”

The new maps include all protected areas in the US: federal, state, and local. Not surprisingly, the “natural” areas near cities tend to be very loud (yellow on the maps below, up to 30dB of additional human noise). Read the rest of this entry »

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.

In yet another unforeseen consequence of global warming, scientists have begun charting the extent of a new underwater sound channel in the Beaufort Sea north of Alaska. As recently as the 1970’s, the water here was coldest just below the ice, but in recent decades two warmer layers have developed, one in the first 50 meters of water, and the second at around 200 meters deep.  Since sound in water tends toward the coldest layers, it used to be dissipated by the rough bottom side of the ice, but now it’s reflected between the warm layers and travels much farther. Research in 2014 and 2016 documented sound transmission across 400 kilometers (250 miles), four times farther than before the emergence of this channel, dubbed the Beaufort Lens.

The near-surface has been warmed by an increased flow of meltwater from rivers and by larger ice-free areas exposed to the sun; this slightly warmer surface water has long been present in summer, but used to disappear in winter.  Meanwhile, warmer waters entering the Beaufort from the North Pacific through the Bering Strait (and perhaps even from the Atlantic, through northern Canada) have contributed to the growth of the deeper warm layer. As is the case for most ocean noise research, the US Navy is a key funder; they’re interested in how increased noise transmission might “dramatically impact the effectiveness of sonar operations.”

The full extent of the Beaufort Lens sound channel is not yet known; further research is planned in the spring of 2018. The area affected is likely to vary with annual changes in the influx of warmer waters and to expand over time as longer-term climate change progresses. Increased shipping traffic is projected to be a major factor in rising ocean noise levels in the Arctic over the coming decades; oil and gas exploration could add to the din if the offshore oil industry rethinks its abandonment of these waters in recent years. In addition, general background noise in some areas could also increase thanks to longer-range transmission of whale calls, which have always been one of the primary sources of ambient sound in these waters.

AEI lay summary of:  Blair HB, Merchant ND, Friedlaender AS, Wiley DN, Parks SE. 2016. Evidence for ship noise impacts on humpback whale foraging behaviour. Biol. Lett. 12: 20160005. http://dx.doi.org/10.1098/rsbl.2016.0005

A new study looks for the first time at the impact of human noise on an important type of humpback whale foraging activity, bottom-feeding on sand lance.  The research took place in the Stellwagen Bank National Marine Sanctuary in the southern Gulf of Maine, where humpback whales routinely do deep dives at night, rolling to their sides when they reach the bottom to forage for the small fish.

To assess the whales’ responses to human noise, D-Tags were placed on ten individuals over the course of two years.  These temporary suction-cup tags record received sound levels that the animal is hearing, as well as tracking the details of their dives.  The tagged whales made 218 dives, 83 with ship noise exposure and 135 without ships nearby.

Here’s an example of the sort of picture that the D-tags can provide:

The results show a 29% decrease in the number of “bottom side-roll feeding events” as the received level of the ship noise increased, as well as a 13-14% decrease in both the descent and ascent rate of the dives.  Interestingly, the increase in received noise level was rather small overall (received level was higher when ship noise was present, but not statistically significantly higher), perhaps indicating that the ships were, on average, not all that close.  As is typical, the team used advanced statistical techniques to tease out modest effects from the subtle and varied data. (In case you’re wondering, they used “linear mixed-effects models” with data “square root transformed to approximate normality,” then calculated effects by “summing Akaike weights of all models.” Sounds good to me!)

The raw numbers put the effects into some more straightforward perspective.   Read the rest of this entry »

Two troubling reports have surfaced regarding beluga whale populations in waters that have become increasingly industrialized and noisy in recent years.  In Quebec’s Saguenay River, the major river system draining into the St. Lawrence, recent years have seen a sharp uptick in dead beluga babies and pregnant mothers; in 2015, these sensitive individuals were half of all known mortalities.  Increased noise is the primary culprit; according to the CBC, “The researchers are working from the theory that beluga calves have soft calls, which may be drowned out by the noise from ships, ferries and boats in the Saguenay and St. Lawrence rivers.”

In Alaska’s Cook Inlet, beluga range has shrunk dramatically over the past couple of decades (see map below), and accelerated in recent years, as ongoing port construction and oil and gas development has introduced increasing levels of noise into these key waters.  It’s unclear whether the smaller range is simply a reflection of a reduced local population, meaning they don’t need to range so far to avoid competing with each other for food, or if they are responding to the increasing chronic noise.  See previous AEInews coverage of the Cook Inlet belugas here.  Recent NMFS research papers on the changes can be accessed at this link, and this in-depth article from a couple years back is a good overview of the current development and research activities.

Some of the most interesting new work in ocean noise is revealing the myriad ways that humanity’s sounds can have negative impacts on ocean life other than marine mammals.  Sure, everyone loves our warm-blooded kin, but there’s way more to the ocean ecosystem than dolphins, humpbacks, and seals.  AEInews has been covering this leading edge for years (see these posts on shellfish larvae, crabs, and squid).  Recently, at the triannual Effects of Noise on Aquatic Life conference, held this year in Dublin, a slew of new papers revealed further concerns.

This post from NRDC summarizes the highlights.  One of the most striking findings was that 6 hours of shipping noise can damage the DNA in the cells of mussels, perhaps due to a stress response; similarly, protein structures in the sensory cells of cuttlefish were damaged by low-frequency noise.  These would be some of the most profound impacts yet discovered; note, though, that the brief summary here does not specify the sound levels—some research on health effects use much higher exposures than are likely in the wild, as a way of identifying possible effects for further study at lower exposure levels.  Other new studies followed on previous ones that suggest many animals respond to noise as if it were a predator; these responses often suggest increased stress, and are waste of precious energy, or disrupt feeding.  Also of note is a one-off anecdotal observation (not yet studied systematically) of a hermit crab exiting its shell after exposure to low-freqency sound; it appeared to be examining its shell, perhaps trying to determine the source of the disruption, or checking for physical damage. While out of its shell, it would be vulnerable to predation.

All this new research is both exciting, as it reveals the vast and subtle role of sound in the natural world, and sobering in facing us with the widespread consequences of our heedless sonic intrusions into wild ecosystems.

Lay summary of
Rosanna CN Agnew, Valerie J Smith, Robert C Fowkes.  Wind Turbines Cause Chronic Stress in Badgers (Meles meles) in Great Britain.  Journal of Wildlife Diseases, 52(3), 2016. DOI: 10.7589/2015-09-231.  Download PDF

A new study out of Britain provides one of the clearest looks at whether wind farms create chronic stress in wildlife populations.  The results are striking—badgers living near turbines had stress levels 265% higher than the control groups—though not yet conclusive.

The researchers used what appears to be a very solid study design, testing cortisol levels in badger hair among 25 badger “setts” (dens, occupied by one or more badger families) separated into two groups: 9 “affected” setts were within 1km of wind farms, and 16 control setts were more than 10km from any wind farm.  They made an effort to assure that control setts were comparable in their habitat types, distance from roads, and geographic spread across Britain.

The overall results are fairly clear-cut.  Here’s a graph of the two groups; the boxes show the 3 quartiles of results in each group (the bottom of the box being the level that 75% of the animals were above; the line across the box showing the level where half the animals were above, half below; and the top of the box the level that 25% of the animals were above), with the bars outside the box showing the remaining scatter of individuals.  The mean among controls was .87, and among the affected group the mean was 3.16

A closer look at the results suggests that, as usual in field studies, there is a lot more going on than the means and medians suggest.  Here we see a plot of the 9 affected setts, with distance to nearest turbine on the bottom axis.  Interestingly, there is a wide scatter of results, with some setts (2 of the 9) showing levels very similar to the controls, about half (4 of the 9) having somewhat elevated levels, and only 3 setts being highly elevated, above the highest of the control setts.  Our first image shows this skew, with the upper quartile of the affected box stretching far above the middle line (and thus pulling up the mean to a significant degree).

This skewing does not invalidate the results; such scatter is very typical of most impact studies.  But it does remind us that there is rarely a simple, universal cause-and-effect.  The authors address many factors that could have contributed to anomalous results, and consider most of them to be quite unlikely; as they summarize, “Although certain intrinsic factors, such as sex, age, and disease status, have been thought to influence cortisol levels, it is very unlikely that the 264% cortisol increase experienced by affected badgers is a result of these factors alone.” Still, these and the other possible confounding factors will deserve closer scrutiny in followup studies.

The authors presume that vibration and noise, and likely infrasound, are the primary stressors, but did not do sound measurements as part of the study.  There was no mention of whether badgers are stressed by tall structures, as some small mammals are (due to predation by hawks).  While it seems likely that badgers are too large to be at risk from above, some confirmation of this would have been helpful to add, if true.

The researchers suggest that their results could have implications for controversies about humans who have reported negative reactions to wind farms, noting that badger hearing range is similar to humans.  A final finding was that the badgers did not appear to acclimate to the wind farms: setts near new wind farms had only slightly higher stress levels than those near long-established ones, where the mean remained well above that of the controls.

I recently returned from the 2016 Ecoacoustics Congress, the 2nd meeting of the new International Society of Ecoacoustics, held this year at Michigan State University in Lansing. It was a very informative gathering of fascinating researchers from around the world; several traveled from Australia, a couple from Taiwan, many from Europe, and some from South America. I’ll add more here soon about this rapidly-advancing field, but for now, I wanted to quickly post a PDF version of my presentation:

Saving High-quality Acoustic Habitat: Identifying areas of relative natural quiet by Jim Cummings

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.

Over the past few years, researchers have developed an increasingly diverse set of platforms for listening in on the world beneath the ocean’s waves.  Now, in addition to recorders deployed in key areas for months at a time and temporary suction-cup acoustic tags on individual whales, a long-anticipated mobile option is moving into more widespread use.  Autonomous gliders offer an enticing combination of attributes: they can operate for weeks or months at a time, exploring a region rather than staying in one place; they can be outfitted with a range of sampling capabilities; and they are relatively inexpensive to build and deploy.  Subsea gliders can dive to 200 meters deep and resurface periodically to transmit data to data centers on shore; they’ve been used for physical sampling of oceanographic data (temperature, salinity, etc.) for many years, but it’s only more recently that acoustic sampling has become common.

The most exciting thing about putting recorders on gliders is that they can operate around the clock, monitoring for whales even in bad weather and at night, when ship-based researchers cannot.  Plus, the cost of operating research ships means that field studies are short and targeted to areas already known to be hot spots for whale activity, while gliders can be used to explore regions that we know less about. In particular, we know that whales tend to move around season-to-season in search of the best feeding opportunities; on the Scotian Shelf in the Canadian Atlantic, some areas that are protected feeding habitat have been largely abandoned in recent years due to lack of prey.  Gliders can help identify where the alternative feeding grounds may be, so they, too, can be protected.

This spring the Canadian WHaLE project (Whales, Habitat, and Listening Experiment) is expanding to the west coast. For three weeks, a six-foot glider will explore waters off Vancouver Island.

“Ocean gliders are a new technique for gaining insights into whale ecology on Canada’s West Coast,” says David Duffus, who leads the west coast project. “Many species of concern under Canada’s Species at Risk Act are termed ‘data deficient.’ We need more information on whale habitats and whale feeding ‘hot spots’ so we can put in protective measures, such as real time whale-alerts for shipping traffic.”

In addition to the longer-term goal of increasing our understanding of changing habitat use patterns, the gliders could also help reduce ship strikes. There is hope that in some especially busy shipping lanes, gliders may offer a new way to let ship captains know when whales are nearby; this is especially important for the critically-endangered North Atlantic right whale.

An ongoing challenge for ocean regulators has been our relatively coarse understanding of where ocean animals are at any given time.  For many species, we’ve been limited to relatively broad-brush data, such as regional population estimates or having a moderately clear idea about particular feeding or breedings areas, with limited knowledge of where these same animals go at other times of year.  All this has made the crucial task of estimating the impacts of human activities (Naval sonar and explosives exercises, oil and gas seismic surveys, construction of new shipping ports) somewhere between difficult and impossible—leading to a mountain of EISs, agency determinations, and court filings over the question of how best to protect ocean life from our noisy actions at sea. Confounding matters for all concerned, on the matter of protecting key habitat, the Navy has sometimes prevailed and sometimes lost in recent challenges.

Over the past decade or so, several projects have been bringing data together from a slew of historical studies, along with doing new surveys in the field that flesh out our understanding of animal distributions.  These efforts are beginning to bear fruit.

This week, a team from Duke University’s Marine Geospatial Lab released a series of maps and new mapping tools to the public and to other researchers, making available data they’ve been compiling for use in the current round of environmental analysis for the Navy’s east coast and Gulf of Mexico training ranges, and for inclusion in NOAA’s ongoing Cetacean and Sound Mapping project (also known as CetSound).

In addition to an open-access paper published in Nature Scientific Reports, a set of comprehensive species-specific supplemental reports (each one running to over a hundred pages), and a good layman’s overview using the Story Map platform, the Lab also has an online mapping portal, OBIS-SEAMAP, that displays annual animal densities for marine mammals, seabirds, sharks, rays, turtles, and even a few lizards of conservation concern.  OBIS-SEAMAP—short for the Ocean Biogeographic Information System: Spatial Ecological Analysis of Megavertebrate Populations—archives hundreds of surveys, satellite telemetry datasets, and photo-ID collections, and has now expanded to include long-term archival of species distribution models. Read the rest of this entry »

A team of researchers from Oregon State University has made the first-ever recordings of what the soundscape is like in the ocean’s deepest spot: the Challenger Deep.  This part of the Mariana Trench is more than 36,000 feet below the surface, but it’s not all that isolated from the normal cacophony of the seas.  As lead investigator Robert Dziak says,

“You would think that the deepest part of the ocean would be one of the quietest places on Earth. Yet there is almost constant noise. The ambient sound field is dominated by the sound of earthquakes, both near and far, as well as distinct moans of baleen whales, and the clamor of a category 4 typhoon that just happened to pass overhead.”

They also heard large ships coming in “loud and strong,” and even the calls of a smaller  toothed whale or dolphin relatively near the surface; you can listen to short sound clips here.  It may seem surprising that sound penetrates so deep.  But of course, seven miles is not really all that far in the ocean; whales routinely communicate over larger distances, and several human sounds sources are readily heard for tens of miles around (or hundreds when caught in a sound-reflecting layer).  What sets the ocean’s depths apart is the extreme density of the water, which can facilitate sound transmission.  Still, it’s a bit disconcerting to realize that no part of the sea is truly free of the acoustic footprints of man.

AEI lay summary of Rob Williams, Christine Erbe, Erin Ashe, Christopher Clark. Quiet(er) marine protected areas. Marine Pollution Bulletin (2015), http://dx.doi.org/10.1016/ j.marpolbul.2015.09.012  View or download paper online

Over the past decade or so, concern about ocean noise has expanded from its initial focus injuries and deaths caused by periodic loud events, such as sonar or seismic surveys.  Many researchers are now working to understand the ways that widespread, chronic shipping noise affects marine creatures’ behavior, foraging success, and stress levels.  Long-term deployment of hydrophones, sound models that extrapolate from shipping data, and slow-but-steady improvements in our knowledge of the hearing ranges and population densities of particular species have all combined to open exciting new avenues for research that can inform policy decisions in the years to come.

Using these new measurement and modeling techniques, researchers can quantify the “acoustic quality” of marine habitats.  This starts with charting the extent of shipping noise, while also considering the different auditory ranges of various species of interest.  Next, researchers map where animals tends to congregate in various seasons, to identify areas that are especially important to each species.

Of particular importance is identifying areas that have, so far, remained relatively free of shipping noise.  If at all possible, we’ll want to avoid extending the human noise footprint into these increasingly rare acoustic havens.  A research team that’s been active on Canada’s southwest coast over the past few years has been at the forefront of these techniques, and has just published a new paper that introduces the concept of “opportunity sites”—areas used by each species that are still relatively quiet, and so have high long-term conservation value.

“We tend to focus on problems in conservation biology. This was a fun study to work on, because we looked for opportunities to protect species by working with existing patterns in noise and animal distribution, and found that British Colombia offers many important habitat for whales that are still quiet,” said Dr. Rob Williams, lead author of the study. “If we think of quiet, wild oceans as a natural resource, we are lucky that Canada is blessed with globally rare pockets of acoustic wilderness. It makes sense to talk about protecting acoustic sanctuaries before we lose them.”

Below left: population density of harbor porpoise in coastal waters of British Columbia; below center: ship noise, weighted to harbor porpoise hearing; below right: opportunity sites to preserve high-quality acoustic habitat for harbor porpoises. Red indicates “highest”, blue “lowest” on all maps.

These new opportunity maps make it painfully obvious how little of each species’ habitat is free of excessive shipping noise. In the example above, harbor porpoises can only find high quality acoustic habitat in a couple of small areas.  Without some concerted effort to protect these areas, they will continue to shrink.

While recognizing that many areas of critical habitat are already too loud (in particular, the entire Seattle/Vancouver region), the authors acknowledge that reducing existing noise is difficult—limiting shipping, or reducing the noise made by boats, has social and economic costs that can be hard to accept.  By contrast, the areas they’ve identified merely need to be maintained in close to their current acoustic condition, which will be far easier to accomplish.  As the authors note:

Generally, large ship noise is far more audible for baleen whales (humpback, fin, etc.) than for smaller toothed whales (dolphins, orca), which vocalize and hear at higher frequencies. That’s not to say that the smaller whales don’t hear big ships; they often do, and in many cases, they respond at a lower sound level than larger whales, so even if the ships are “fainter” to their ears, their reactions may be similar.

While this paper steers clear of any sort of advocacy tone, and does no more than present the new “opportunity sites” analysis and mapping technique, the waters being studied are at the center of a contentious public policy debate.  The proposed Northern Gateway pipeline from the oil sands region of Alberta would dramatically increase tanker traffic to the existing deep-water port at Kitimat (yellow arrow, left).  Such an increase through Caamano Sound (red arrow, left) would threaten the humpback whale opportunity site (map, left) identified just south of the Sound.  Several years ago, co-author Rob Williams told reporters, “Caamano Sound may be one of the last chances we have on this coastline to protect an acoustically quiet sanctuary for whales. … We don’t exactly know why this area is so rich, but there are some long, narrow channels that serve as bottlenecks for food, making it easier for whales to feed.” A consortium of environmental organizations is currently challenging the Canadian government’s approval of the pipeline, claiming that the approval did not take into account the humpback recovery plan, identifying Hecate Strait (the larger area between the mainland and the large offshore island) as a critical humpback feeding ground.  The pipeline is being challenged on several fronts (including strong opposition from B.C. First Nations communities); considering acoustic habitat protection, limiting new ship traffic during the times of year when the current opportunity sites are being heavily used would seem to be the least we can do.

Somewhere out in the vast expanse of the Snake River plain this summer, the sounds of a natural gas compressor floats across the sage-strewn landscape.  Look around though, and you won’t see any wellpads or boxy compressor stations.  If your eyes are sharp, you may spy the source of the intrusive sound: a large solar-powered speaker.

It’s part of phase two of a study looking into the effects of human noises on wildlife.  Phase one was the “Phantom Road,” a half-mile string of speakers set up in an Idaho forest, which found that traffic noise caused notable changes in the makeup of the nearby bird population.  About half of the species in the area showed some avoidance of the sounds, with two species nearly absent when the speakers were on (one species preferred the noisy periods).  This study was summarized in AEI’s 2014 poster that summarized research on “The Effects of Chronic Moderate Noise on Animal Behavior and Distribution.”

By using speakers, rather than studying actual roads or oil development sites, researchers are able to separate out the effect of noise from the effects of the physical disruptions of the habitat (the loss of plant cover at the site itself, and access roads to the facilities).

The oil field study, which includes a six sites with speakers and six control sites with no added noise, is looking at effects of the noise on birds, bats, and insects.  And, they’ve brought birders out to their sites to see how oil development may affect their ability to hear birds and enjoy the landscape.  Some of the birders were surprised at how much even distant compressor noise interfered.  “The whole thing has been ear-opening, shall we say,” said Jim Lyons of Boise. “To be part of this is very stimulating, very interesting. I am going to think about it from now on.”

Several independent research projects that are listening to fish and whales in waters along the coast from New Jersey to Maine have joined together as the NorthEast Passive Acoustic sensing Network (NEPAN).  This map shows the location of the various research programs that will be taking place through 2017:

The NEPAN website offers a good overview of the aims of each of these projects.  Of particular interest is a real-time buoy deployed near a Coast Guard gunnery range off Rhode Island, which will help the Coast Guard to avoid initiating live-explosive exercises when any of the few remaining critically endangered North Atlantic right whales are in the area.  The array of long-term recorders along the edge of the continental shelf will also provide some key new information on seasonal presence of many whale species, as well as helping clarify how far offshore they tend to be during migration (again, especially crucial information for the right whales).

The Navy and NMFS suffered a stunning legal defeat over the latest 5-year EIS and permits governing training exercises in Hawaii, California, and waters in between.  In marked contrast to other recent court rulings, which found fault with some procedural issues but largely backed the Navy and NMFS’s collaborative planning results (see detailed AEI summaries of 2014 rulings on the Pacific Northwest training range and global low-frequency sonar permits), US District Court Judge Susan Moki Olway vehemently rejected several key aspects of the permitting for the Hawaii-Southern California Training and Testing (“HSTT”) Study Area. (Note: while sonar has been the focus of most public concern, these trainings also involve live ammunition, explosions, etc., that are responsible for most of the anticipated behavioral disruptions and nearly all the injuries and deaths.)

The primary target of the legal challenges was the National Marine Fisheries Service (NMFS), which issues the permits (Letters of Authorization) and the Biological Opinion that underly the permit conditions and take numbers. The Navy’s Environmental Impact Statement (EIS) was not directly challenged (a Supreme Court ruling has left the Navy with broad discretion and little room for legal challenges), but the EIS is accepted as sufficient by NMFS, and Judge Olway made a point of chastising NMFS for being too quick to simply adopt much of the Navy’s reasoning about both the impact on animal populations and the practicality (or lack thereof) of keeping training activities out of some areas.

The ruling seems to call for a fairly substantial revision of the EIS, the Biological Opinion, and the take numbers authorized by the permits; still, it may be likely that these documents can indeed be revised to fix the shortcomings identified by the Court, without substantially reducing the training activities being planned.  Also, an appeal to a higher court is possible, or likely, given the broad implications of the ruling.

UPDATE, September 2015: As it turned out, the Navy and NRDC negotiated a settlement, adding a few exclusion zones for the duration of the current five-year authorization. It remains to be seen how the larger issues raised by the ruling may affect the next round of Navy EIS and NMFS authorizations.

Nonetheless, this ruling is the most fundamental challenge to the current Navy and NMFS planning process since the original lawsuits that helped trigger the Navy to begin producing EISs and NMFS to issue permits.  Among the key issues that were successfully challenged:

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Next week in Denver, the American Wind and Wildlife Institute and National Wind Coordinating Collaborative will be hosting their 10th Wind and Wildlife Research Meeting.  For the second time, I put together a research summary poster for the event (here’s the first one).  Most of the presentations at this meeting are focused on direct mortality (birds or bats hitting turbines) and habitat-disruption issues; in recent years, concerns about the sage grouse on the northern plains and the Fish and Wildlife Service’s new eagle permit process have also been hot topics.

As usual, my contribution is one of the few looking at the effects of the moderate noise around wind farms.  It offers an overview of the current state of our understanding of the ways chronic moderate noise can change animal behavior and communication, shift population structure, and increase physiological stress.  It includes data from studies on sage grouse, frogs, mammals, and songbirds, as well as discussion of other considerations, uncertainties, and future research needs.

Effects of chronic moderate noise on animal behavior and distribution

AEI lay summary of four recent papers:
Simpson SD, Purser J, Radford AN (2014). Anthropogenic noise compromises antipredator behavior in European eels. Global Change Biology (2014), doi: 10.1111/gcb.12685
Voellmy IK, Purser J, Simpson SD, Radford AN (2014). Increased Noise Levels Have Different Impacts on the Anti-Predator Behaviour of Two Sympatric Fish Species. PLoS ONE 9(7): e102946. doi:10.1371/journal.pone.0102946
Nedelec SL, Radford AN, Simpson SD, Nedelec B, Lecchini D, Mills SC (2014). Anthropogenic noise playback impairs embryonic development and increases mortality in a marine invertebrate. Sci. Rep. 4, 5891; DOI:10.1038/srep05891 (2014).
Erica Staaterman, Claire B. Paris, Andrew S. Krough (2014). First evidence of fish larvae producing sounds. Biol. Lett. 2014 10, 20140643.

It used to be that most concern about human noise and ocean life was centered on whales and the two loudest sound sources: sonar and seismic surveys.  But in recent years, we’ve seen a growing wave of studies looking at how chronic, moderate ship noise can interfere with normal behavior and development of other creatures, including squid, fish, crustaceans, and other “lower” species.  Four recent studies add to the list of known or suspected ways that shipping and recreational boat noise may be wreaking previously unsuspected havoc throughout the oceanic web of life.

The most dramatic results came in a study of eels’ responses to predators (above). When exposed to ship noise, only half as many eels responded to an ambush attack from a predator (just 38% reacted, down from 80%); and, those that did react did so 25% slower than normal. Likewise, researchers tested eels’ ability to detect a “pursuit” predator that follows the eels before attacking; in this case, the eels in ship noise were caught twice as quickly.  Looking deeper, the researchers examined how noise affects metabolic rates, stress, and breathing rates, and an interesting feature of eel life, the preference for using one side of their body when interacting with other eels and when hunting.  The researchers explain:

“In the same way we write using our right or left hands, fish have a preferred side to approach a predator or to stay next to shoal mates with. We watched each eel as it explored a maze in ambient conditions to classify its right or left bias, then we exposed half to ship noise and half to more ambient noise. Their preferences went away when they were exposed,” says Dr Steve Simpson of the University of Exeter, lead researcher on the study. The team suspect this means ship noise affects eels’ cognitive processes, which could mean other processes, like learning, may also be affected. Alongside raised metabolic and ventilation rates, the scientists note the stress being caused by the shipping noise is similar to the levels fish exhibit in ocean acidification studies.

“We know shipping isn’t going to stop, but we can do things like move a shipping lane so it doesn’t interact with the migrations paths of animals,” Simpson suggests. “It’s a pollutant we have more control over than something like atmospheric carbon dioxide. These animals are having to deal with all the stressors globally, so if we can alleviate just one it might give the animals more resilience to other stressors like ocean acidification, which will come later.”

A study of two species of small fish highlights species differences and the ways that noise can alter behavior in unexpected ways.  Here, one species of fish exposed to ship noise actually responded more quickly to the presence of a predator,

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

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

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

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

…

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

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

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

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

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

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.