Detecting blue whales from acoustic data

By Dawn Barlow, PhD student, OSU Department of Fisheries and Wildlife, Geospatial Ecology of Marine Megafauna Lab

In January of 2016, five underwater recording units were dropped to the seafloor in New Zealand to listen for blue whales (Fig. 1). These hydrophones sat listening for two years, brought to the surface only briefly every six months to swap out batteries and offload the data. Through all seasons and conditions when scientists couldn’t be on the water, they recorded the soundscape, generating a wealth of acoustic data with the potential to greatly expand our knowledge of blue whale ecology

Figure 1. Locations of the five Marine Autonomous Recording Units (MARUs) in the South Taranaki Bight region of New Zealand.

We have established that blue whales are present in New Zealand waters year-round 1. However, many questions remain regarding their distribution across daily, seasonal, and yearly scales. Our two-year acoustic dataset from five hydrophones throughout the STB region is a goldmine of information on blue whale occurrence patterns and the soundscape they inhabit. Having year-round occurrence data will allow us to examine what environmental and anthropogenic factors may influence blue whale distribution patterns. The hydrophones were listening for whales around the clock, every day, while we were on the other side of the world awaiting the recovery of the data to answer our questions.

Before any questions of seasonal distribution or anthropogenic impacts and noise can be addressed, however, we need to know something far more basic: when and where did we record blue whale vocalizations? This may seem like a simple, stepping-stone question, but it is actually quite involved, and the reason I spent the last month working with a team of acousticians at Cornell University’s Center for Conservation Bioacoustics. The expert research group here at Cornell, led by Dr. Holger Klinck, have been instrumental in our New Zealand blue whale research, including developing and building the recording units, hydrophone deployment and recovery, data processing, analysis, and advice. I am thrilled to work with all of them, and had an incredibly productive month of learning about acoustics from the best.

Blue whales produce multiple vocalizations that we are interested in documenting. The New Zealand song (Fig. 2A) is highly stereotyped and unique to the Southwest Pacific Ocean 2,3. Low-frequency downsweeps, or “D calls” (Fig. 2B), are far more variable and produced by blue whale populations around the world 4. Furthermore, Antarctic blue whales produce a highly-stereotyped “Z call” (Fig. 2C) and are known to be present in New Zealand waters occasionally 5.

Figure 2. Spectrograms of (A) the New Zealand blue whale song, (B), D calls, and (C) Antarctic Z calls.

One way to determine when blue whales were vocalizing is for an analyst to manually review the entirety of the two years of sound recordings for each of the five hydrophones by hand to scan for and select individual vocalizations. An alternative approach is to develop a detector algorithm to locate calls in the data based on their stereotypical characteristics. Over the past month I built, tested, and ran detectors for each blue whale call type using what is called a data template detector. This technique uses example signals from the data that the analyst selects as templates. The templates should be clear signals, and representative of the variation in calls contained in the dataset. Then, by comparing pixel characteristics between the template spectrograms and the spectrogram of the recording of interest using certain matching criteria (e.g. threshold for spectrogram correlation, detection frequency range), the algorithm searches for other signals like the templates in the full dataset. For example, in Fig. 3 you can see units of blue whale song I selected as templates for my detector.

Figure 3. Spectrogram of selected sound clips of New Zealand blue whale song, with units used as templates for a detector shown inside the teal boxes.

Testing the performance of a detector algorithm is critical. Therefore, a dataset is needed where calls were identified by an analyst and then used as the “ground truth”, to which the detector results are compared. For my ground truth dataset, I took a subset of 52 days and hand-browsed the spectrograms to identify and log New Zealand blue whale song, D calls, and Antarctic Z calls. In evaluating detector performance, there are three important metrics that need to be weighed: precision (the proportion of detections that are true), recall (the proportion of true calls identified by the detector), and false alarm rate (the number of false positive detections per hour). Ideally, the detector should be optimized to maximize precision and recall and minimize the false positives.

The STB region is highly industrial, and our two-year acoustic dataset contains periods of pervasive seismic airgun noise from oil and gas exploration. Ideally, a detector would be able to identify blue whale vocalizations even in the presence of airgun operations that dominate the soundscape for months. For blue whale song, the detector did quite well! With a precision of 0.91 and recall of 0.93, the detector could pick out song units over airgun noise (Fig. 4). A false alarm rate of 8 false positives per hour is a sacrifice worth making to identify song during seismic operations (and the false positives will be removed in a subsequent step). For D calls, seismic survey activity presented a different challenge. While the detector did well at identifying D calls during airgun operation, the first several detector attempts also logged every single airgun blast as a blue whale vocalization—clearly problematic. Through an iterative process of selecting template signals, and adjusting the number of templates used and the correlation threshold, I was able to come up with a detector which selected D calls and missed most airgun blasts. This success felt like a victory.

Figure 4. An example of spectrograms of simultaneous recordings from the five hydrophones illustrating seismic airgun noise (strong broadband signals that appear as repetitive black, vertical lines) overlapping New Zealand blue whale song. The red boxes are detection events selected by the detector, demonstrating its ability to capture song even during airgun operation.

After this detector development and validation process, I ran each detector on the full two-year acoustic dataset for all five recording units. This step was a good exercise in patience as I eagerly awaited the outputs for the many hours they took to run. The next step in the process will be for me to go through and validate each detector event to eliminate any false positives. However, running the detectors on the full dataset has allowed for exciting preliminary examinations of seasonal blue whale acoustic patterns, which need to be refined and expanded upon as the analysis continues. For example, sometimes the New Zealand song dominates the recordings on all hydrophones (Fig. 5), whereas other times of year song is less common. Similarly, there appear to be seasonal patterns in D calls and Antarctic Z calls, with peaks and dips in detections during different times of year.

Figure 5. An example spectrogram of simultaneous recordings from all five hydrophones during a time when New Zealand blue whale song dominated the recordings, with numerous, overlapping calls.

As with many things, the more questions you ask, the more questions you come up with. From preliminary explorations of the acoustic data my head is buzzing with ideas for further analysis and with new questions I hadn’t thought to ask of the data before. My curiosity has been fueled by scrolling through spectrograms, looking, and listening, and I am as excited as ever to continue researching blue whale ecology. I would like to thank the team at the Center for Conservation Bioacoustics for their support and guidance over the past month, and I look forward to digging deeper into the stories being told in the acoustic data!

Figure 6. A pair of blue whales observed in February 2017 in the South Taranaki Bight. Photo: L. Torres.

References

1.          Barlow, D. R. et al. Documentation of a New Zealand blue whale population based on multiple lines of evidence. Endanger. Species Res. 36, 27–40 (2018).

2.          McDonald, M. A., Mesnick, S. L. & Hildebrand, J. A. Biogeographic characterisation of blue whale song worldwide: using song to identify populations. J. Cetacean Res. Manag. 8, 55–65 (2006).

3.          Balcazar, N. E. et al. Calls reveal population structure of blue whales across the Southeast Indian Ocean and the Southwest Pacific Ocean. J. Mammal. 96, 1184–1193 (2015).

4.          Oleson, E. M. et al. Behavioral context of call production by eastern North Pacific blue whales. Mar. Ecol. Prog. Ser. 330, 269–284 (2007).

5.          McDonald, M. A. An acoustic survey of baleen whales off Great Barrier Island, New Zealand. New Zeal. J. Mar. Freshw. Res. 40, 519–529 (2006).


Coastal oceanography takes patience

Joe Haxel, Acoustician, Assistant Professor, CIMRS/OSU

Greetings GEMM Lab blog readers. My name is Joe Haxel and I’m a close collaborator with Leigh and other GEMM lab members on the gray whale ecology, physiology and noise project off the Oregon coast. Leigh invited me for a guest blog appearance to share some of the acoustics work we’ve been up to and as you’ve probably guessed by now, my specialty is in ocean acoustics. I’m a PI in NOAA’s Pacific Marine Environmental Laboratory’s Acoustics Program and OSU’s Cooperative Institute for Marine Resources Studies where I use underwater sound to study a variety of earth and ocean processes.

As a component of the gray whale noise project, during the field seasons of 2016 and 2017 we recorded some of the first measurements of ambient sound in the shallow coastal waters off Oregon between 7 and 20 meters depth. In the passive ocean acoustics world this is really shallow, and with that comes all kinds of instrument and logistical challenges, which is probably one of the main reasons there is little or no acoustic baseline information in this environment.

For instance, one of the significant challenges is rooted in the hydrodynamics surrounding mobile recording systems like the drifting hydrophone we used during the summer field season in 2016 (Fig 1). Decoupling motion of the surface buoy (e.g., caused by swell and waves) from the submerged hydrophone sensor is critical, and here’s why. Hydrophones convert pressure fluctuations at the sensor/ water interface to a calibrated voltage recorded by a logging system. Turbulence resulting from moving the sensor up and down in the water column with surface waves introduces non-acoustic pressure changes that severely contaminate the data for noise level measurements. Vertical and horizontal wave motions are constantly acting on the float, so we needed to engineer compliance between the surface float and the suspended hydrophone sensor to decouple these accelerations. To overcome this, we employed a couple of concepts in our drifting hydrophone design. 1) A 10 cm diameter by 3 m long spar buoy provided floatation for the system. Spar buoys are less affected by wave motion accelerations compared to most other types of surface floatation with larger horizontal profiles and drag. 2) A dynamic shock cord that could stretch up to double its resting length to accommodate vertical motion of the spar buoy; 3) a heave plate that significantly reduced any vertical motion of the hydrophone suspended below it. This was a very effective design, and although somewhat cumbersome in transport with the RHIB between deployment sites, the acoustic data we collected over 40 different drifts around Newport and Port Orford in 2016 was clean, high quality and devoid of system induced contamination.

Figure 1. The drifting hydrophone system used for 40 different drifts recording ambient noise levels in 7-20 m depths in the Newport and Port Orford, OR coastal areas.

 

 

 

 

 

 

 

 

 

 

 

 

Spatial information from the project’s first year acoustic recordings using the drifting hydrophone system helped us choose sites for the fixed hydrophone stations in 2017. Now that we had some basic information on the spatial variability of noise within the study areas we could focus on the temporal objectives of characterizing the range of acoustic conditions experienced by gray whales over the course of the entire foraging season at these sites in Oregon. In 2017 we deployed “lander” style instrument frames, each equipped with a single, omni-directional hydrophone custom built by Haru Matsumoto at our NOAA/OSU Acoustics lab (Fig. 2). The four hydrophone stations were positioned near each of the ports (Yaquina Bay and Port Orford) and in partnership with the Oregon Department of Fish and Wildlife Marine Reserves program in the Otter Rock Marine Reserve and the Redfish Rocks Marine Reserve. The hydrophones were programmed on a 20% duty cycle, recording 12 minutes of every hour at 32 kHz sample rate, providing spectral information in the frequency band from 10 Hz up to a 13 kHz.

Figure 2. The hydrophone (black cylinder) on its lander frame ready for deployment.

Here’s where the story gets interesting. In my experience so far putting out gear off the Oregon coast, anything that has a surface expression and is left out for more than a couple of weeks is going to have issues. Due to funding constraints, I had to challenge that theory this year and deploy 2 of the units with a surface buoy. This is not typically what we do with our equipment since it usually stays out for up to 2 years at a time, is sensitive, and expensive. The 2 frames with a surface float were going to be deployed in Marine Reserves far enough from the traffic lanes of the ports and in areas with significantly less traffic and presumably no fishing pressure.  The surface buoy consisted of an 18 inch diameter hard plastic float connected to an anchor that was offset from the instrument frame by a 150 foot weighted groundline. The gear was deployed off Newport in June and Port Orford in July. What could go wrong?

After monthly buoy checks by the project team, including GPS positions, and buoy cleanings my hopes were pretty high that the surface buoy systems might actually make it through the season with recoveries scheduled in mid-October. Had I gambled and won? Nope. The call came in September from Leigh that one of the whale watching outfits in Depoe Bay recovered a free floating buoy matching ours. Bummer. Alternative recovery plans initiated and this is where things began to get hairy. Fortunately, we had an ace in our back pocket. We have collaborators at the Oregon Coast Aquarium (OCA) who have a top-notch research diving team led by Jim Burke. In the last week of October, they performed a successful search dive on the missing unit near Gull Rock and attached a new set of floats directly to the instrument frame. The divers were in the water for a short 20 minutes thanks to the good series of marks recorded during the buoy checks throughout the summer (Fig. 3).

Figure 3. OCA divers, Jenna and Doug, heading out for a search dive to locate and mark the Gull Rock hydrophone lander.

 

 

 

 

 

We had surface marker floats on the frame, but there was a new problem. Video taken by Jenna and Doug from the OCA dive team revealed the landers were pretty sanded in from a couple of recent October storms (Fig. 4). Ugghhh!

Figure 4. Sanded in lander at Gull Rock. Notice the sand dollars and bull kelp wrapped on the frame.

Alternative recovery plan adjustment: we’re gonna need a diver assisted recovery with 2 boats. One to bring a dive team to air jet the sand out away from the legs of the frame and another larger vessel with pulling power to recover the freed lander. Enter the R/V Pacific Surveyor and Capt. Al Pazar. Al, Jim and I came up with a new recovery plan and only needed a decent weather window of a few hours to get the job done. Piece of cake in November off the Oregon coast, right?

The weather finally cooperated in early December in-line with the OCA dive team and R/V Pacific Surveyor’s availability. The 2 vessels and crew headed up to Gull Rock for the first recovery operation of the day. At first we couldn’t locate the surface floats. Oh no. It seemed the rough fall/ winter weather and high seas since late October were too much for the crab floats? As it turns out, we eventually found the floats eastward about 200 m but couldn’t initially see them in the glare and whitecapping conditions that morning. The lander frame had broken loose from its weakened anchor legs in the heavy weather (as it was designed to do through an Aluminum/ Stainless Steel galvanic reaction over time) and rolled or hopped eastward by about 200 m (Fig. 5). Oh dear!

Figure 5. A hydrophone lander after recovery. Notice all but 1 of the concrete anchor legs missing from the recovered lander and the amount of bio-fouling on the hydrophone (compared to Figure 2).

 

 

 

 

 

 

Thankfully, the hydrophone was well protected, and no air jetting was required. With OCA divers out of the water and clear, the Pacific Surveyor headed over to the floats and easily pulled the lander frame and hydrophone on board (Fig. 6). Yipee!

On to the next hydrophone station. This station, deployed ~ 800 m west of the south reef off of South Beach near the Yaquina Bay port entrance. It was deployed entirely subsurface and was outfitted with an acoustic release transponder that I could communicate with from the surface and command to release a pop-up messenger float and line for eventual recovery of the instrument frame. Once on station, communication with the release was established easily (a good start) and we began ranging and moving the OCA vessel Gracie Lynn in to a position within about 2 water depths of the unit (~40 m). I gave the command to the transponder and the submerged release confirmed it was free of its anchor and heading for the surface, but it never made it. Uh oh. Turns out this lander had also broke free of its anchored legs and rolled/ hopped 800 m eastward until it was pinned up against the boulder structure of the south reef. Amazingly, OCA divers Jenna and Doug located the messenger float ~ 5 m below the surface and the messenger line had been fouled by the rolling frame so it could not reach the surface. They dove down the messenger line and attached a new recovery line to the lander frame and the Pacific Surveyor hauled up the frame and hydrophone in-tact (Fig. 6). Double recovery success!

Figure 6. R/V Pacific Surveyor recovering hydrophone landers off Gull Rock and South Beach.

The hydrophone data from both systems looks outstanding and analysis is underway. This recovery effort took a huge amount of patience and the coordination of 3 busy groups (NOAA/OSU, OCA, Capt. Al). Thanks to these incredible collaborations and some heroic diving from Jim Burke and his OCA dive team, we now have a unique and unprecedented shallow water passive acoustic data set from the energetic waters off the Oregon coast.

So that’s some of the story from the 2016 and 2017 field season acoustic point of view. I’ll save the less exciting, but equally successful instrument recoveries from Port Orford for another time.

A Marine Mammal Odyssey, Eh!

By Leila Lemos, PhD student

Dawn Barlow, MS student

Florence Sullivan, MS

The Society for Marine Mammalogy’s Biennial Conference on the Biology of Marine Mammals happens every two years and this year the conference took place in Halifax, Nova Scotia, Canada.

Logo of the Society for Marine Mammalogy’s 22nd Biennial Conference on the Biology of Marine Mammals, 2017: A Marine Mammal Odyssey, eh!

The conference started with a welcome reception on Sunday, October 22nd, followed by a week of plenaries, oral presentations, speed talks and posters, and two more days with different workshops to attend.

This conference is an important event for us, as marine mammalogists. This is the moment where we get to share our projects (how exciting!), get important feedback, and hear about different studies that are being conducted around the world. It is also an opportunity to network and find opportunities for collaboration with other researchers, and of course to learn from our colleagues who are presenting their work.

The GEMM Lab attending the opening plenaries of the conference!

The first day of conference started with an excellent talk from Asha de Vos, from Sri Lanka, where she discussed the need for increased diversity (in all aspects including race, gender, nationality, etc.) in our field, and advocated for the end of “parachute scientists” who come into a foreign (to them) location, complete their research, and then leave without communicating results, or empowering the local community to care or act in response to local conservation issues.  She also talked about the difficulty that researchers in developing countries face accessing research that is hidden behind journal pay walls, and encouraged everyone to get creative with communication! This means using blogs and social media, talking to science communicators and others in order to get our stories out, and no longer hiding our results behind the ivory tower of academia.  Overall, it was an inspirational way to begin the week.

On Thursday morning we heard Julie van der Hoop, who was this year’s recipient of the F.G. Wood Memorial Scholarship Award, present her work on “Drag from fishing gear entangling right whales: a major extinction risk factor”. Julie observed a decrease in lipid reserves in entangled whales and questioned if entanglements are as costly as events such as migration, pregnancy or lactation. Tags were also deployed on whales that had been disentangled from fishing gear, and researchers were able to see an increase in whale speed and dive depth.

Julie van der Hoop talks about different drag forces of fishing gears
on North Atlantic Right Whales.

There were many other interesting talks over the course of the week. Some of the talks that inspired us were:

— Stephen Trumble’s talk “Earplugs reveal a century of stress in baleen whales and the impact of industrial whaling” presented a time-series of cortisol profiles of different species of baleen whales using earplugs. The temporal data was compared to whaling data information and they were able to see a high correlation between datasets. However, during a low whaling season concurrent to the World War II in the 40’s, high cortisol levels were potentially associated to an increase in noise from ship traffic.

— Jane Khudyakov (“Elephant seal blubber transcriptome and proteome responses to single and repeated stress”) and Cory Champagne (“Metabolomic response to acute and repeated stress in the northern elephant seal”) presented different aspects of the same project. Jane looked at down/upregulation of genes (downregulation is when a cell decreases the quantity of a cellular component, such as RNA or protein, in response to an external stimulus; upregulation is the opposite: when the cell increases the quantity of cellular components) to check for stress. She was able to confirm an upregulation of genes after repeated stressor exposure. Cory checked for influences on the metabolism after administering ACTH (adrenocorticotropic hormone: a stimulating hormone that causes the release of glucocorticoid hormones by the adrenal cortex. i.e., cortisol, a stress related hormone) to elephant seals. By looking only at the stress-related hormone, he was not able to differentiate acute from chronic stress responses. However, he showed that many other metabolic processes varied according to the stress-exposure time. This included a decrease in amino acids, mobilization of lipids and upregulation of carbohydrates.

— Jouni Koskela (“Fishing restrictions is an essential protection method of the Saimaa ringed seal”) talked about the various conservation efforts being undertaken for the endangered Lake Saimaa ringed seal. Gill nets account for 90% of seal pup mortality, but if new pups can reach 20kg, only 14% of them will drown in these fishing net entanglements. Working with local industry and recreational interests, increased fishing restrictions have been enacted during the weaning season. In addition to other year-round restrictions, this has led to a small, but noticeable upward trend in pup production and population growth! A conservation success story is always gratifying to hear, and we wish these collaborative efforts continued future success.

— Charmain Hamilton (“Impacts of sea-ice declines on a pinnacle Arctic predator-prey relationship: Habitat, behaviour, and spatial overlap between coastal polar bears and ringed seals”) gave a fascinating presentation looking at how changing ice regimes in the arctic are affecting spatial habitat use patterns of polar bears. As ice decreases in the summer months, the polar bears move more, resulting in less spatial overlap with ringed seal habitat, and so the bears have turned to targeting ground nesting seabirds.  This spatio-temporal mismatch of traditional predator/prey has drastic implications for arctic food web dynamics.

— Nicholas Farmer’s presentation on a Population Consequences of Disturbance (PCoD) model for assessing theoretical impacts of seismic survey on sperm whale population health had some interesting parallels with new questions in our New Zealand blue whale project. By simulating whale movement through modeled three-dimensional sound fields, he found that the frequency of the disturbance (i.e., how many days in a row the seismic survey activity persisted) was very important in determining effects on the whales. If the seismic noise persists for many days in a row, the sperm whales may not be able to replenish their caloric reserves because of ongoing disturbance. As you can imagine, this pattern gets worse with more sequential days of disturbance.

— Jeremy Goldbogen used suction cup tags equipped with video cameras to peer into an unusual ecological niche: the boundary layer of large whales, where drag is minimized and remoras and small invertebrates compete and thrive. Who would have thought that at a marine mammal conference, a room full of people would be smiling and laughing at remoras sliding around the back of a blue whale, or barnacles filter feeding as they go for a ride with a humpback whale? Insights from animals that occupy this rare niche can inform improvements to current tag technologies.

The GEMM Lab was well represented this year with six different talks: four oral presentations and two speed talks! It is evident that all of our hard work and preparation, such as practicing our talks in front of our lab mates two weeks in advance, paid off.  All of the talks were extremely well received by the audience, and a few generated intelligent questions and discussion afterwards – exactly as we hoped.  It was certainly gratifying to see how packed the room was for Sharon’s announcement of our new method of standardizing photogrammetry from drones, and how long the people stayed to talk to Dawn after her presentation about an unique population of New Zealand blue whales – it took us over an hour to be able to take her away for food and the celebratory drinks she deserved!

GEMM Lab members on their talks. From left to right, top to bottom: Amanda Holdman, Leila Lemos, Solène Derville, Dawn Barlow, Sharon Nieukirk, and Florence Sullivan.

 

GEMM Lab members at the closing celebration. From left to right: Florence Sullivan, Leila Lemos, Amanda Holdman, Solène Derville, and Dawn Barlow.

We are not always serious, we can get silly sometimes!

The weekend after the conference many courageous researchers who wanted to stuff their brains with even more specialized knowledge participated in different targeted workshops. From 32 different workshops that were offered, Leila chose to participate in “Measuring hormones in marine mammals: Current methods, alternative sample matrices, and future directions” in order to learn more about the new methods, hormones and matrices that are being used by different research groups and also to make connections with other endocrinologist researchers. Solène participated in the workshop “Reproducible Research with R, Git, and GitHub” led by Robert Shick.  She learned how to better organize her research workflow and looks forward to teaching us all how to be better collaborative coders, and ensure our analysis is reproducible by others and by our future selves!

On Sunday none of us from the GEMM Lab participated in workshops and we were able to explore a little bit of the Bay of Fundy, an important area for many marine mammal species. Even though we didn’t spot any marine mammals, we enjoyed witnessing the enormous tidal exchange of the bay (the largest tides in the world), and the fall colors of the Annaoplis valley were stunning as well. Our little trip was fun and relaxing after a whole week of learning.

The beauty of the Bay of Fundy.

GEMM Lab at the Bay of Fundy; from left to right: Kelly Sullivan (Florence’s husband and a GEMM Lab fan), Florence Sullivan, Dawn Barlow, Solène Derville, and Leila Lemos.

We do love being part of the GEMM Lab!

It is amazing how refreshing it is to participate in a conference. So many ideas popping up in our heads and an increasing desire to continue doing research and work for conservation of marine mammals. Now it’s time to put all of our ideas and energy into practice back home! See you all in two years at the next conference in Barcelona!

Flying out of Halifax!

Hearing is believing

Dr. Leigh Torres, Geospatial Ecology of Marine Megafauna Lab, Marine Mammal Institute, Oregon State University

Dr. Holger Klinck, Bioacoustics Research Program, Cornell Lab of Ornithology, Cornell University

For too long the oil and gas industry has polluted the ocean with seismic airgun noise with little consequence. The industry uses seismic airguns in order to find their next lucrative reserve under the seafloor, and because their operations are out of sight and the noise is underwater many have not noticed this deafening (literally1) noise. As terrestrial and vision-dependent animals, we humans have a hard time appreciating the importance of sound in the marine environment. Most of the ocean is a dark place, where vision does not work well, so many animals are dependent on sound to survive. Especially marine mammals like whales and dolphins.

But, hearing is believing, so let’s have a listen to a recording of seismic airguns firing in the South Taranaki Bight (STB) of New Zealand, a known blue whale feeding area. This is a short audio clip of a seismic airgun firing every ~8 seconds (a typical pattern). Before you hit play, close your eyes and imagine you are a blue whale living in this environment.

Now, put that clip on loop and play it for three months straight. Yes, three months. This consistent, repetitive boom is what whales living in a region of oil and gas exploration hear, as seismic surveys often last 1-4 months.

So, how loud is that, really? Your computer or phone speaker is probably not good enough to convey the power of that sound (unless you have a good bass or sub-woofer hooked up). Industrial seismic airgun arrays are among the loudest man-made sources2 and the noise emitted by these arrays can travel thousands of kilometers3. Noise from a single seismic airgun survey can blanket an area of over 300,000 km2, raising local background noise levels 100-fold4.

Now, oil and gas representatives frequently defend their seismic airgun activities with two arguments, both of which are false. You can hear both these arguments made recently in this interview by a representative of the oil and gas industry in New Zealand defending a proposal to conduct a 3 month-long seismic survey in the STB while blue whales will be feeding there.

First, the oil and gas industry claim that whales and dolphins can just leave the area if they choose. But this is their home, where they live, where they feed and breed. These habitats are not just anywhere. Blue whales come to the STB to feed, to sustain their bodies and reproductive capacity. This habitat is special and is not available anywhere else nearby, so if a whale leaves the STB because of noise disturbance it may starve. Similarly, oil and gas representatives have falsely claimed that because whales stay in the area during seismic airgun activity this indicates they are not being disturbed. If you had the choice of starving or listening to seismic booming you might also choose the latter, but this does not mean you are not disturbed (or annoyed and stressed). Let’s think about this another way: imagine someone operating a nail gun for three months in your kitchen and you have nowhere else to eat. You would stay to feed yourself, but your stress level would elevate, health deteriorate, and potentially have hearing damage. During your next home renovation project you should be happy you have restaurants as alternative eateries. Whales don’t.

Second, the oil and gas industry have claimed that the frequency of seismic airguns is out of the hearing range of most whales and dolphins. This statement is just wrong. Let’s look at the spectrogram of the above played seismic airgun audio clip recorded in the STB. A spectrogram is a visual representation of sound (to help us vision-dependent animals interpret sound). Time is on the horizontal axis, frequency (pitch) is on the vertical axis, and the different colors on the image indicate the intensity of sound (loudness) with bright colors illustrating areas of higher noise. Easily seen is that as the seismic airgun blasts every ~8 seconds, there is elevated noise intensity across all frequencies (bright yellow, orange and green bands). This noise intensity is especially high in the 10 – 80 Hz frequency range, which is exactly where many large baleen whales – like the blue whale – hear and communicate.

A spectrogram of the above played seismic airgun audio clip recorded in the South Taranaki Bight, New Zealand. Airgun pulses every ~8 seconds are evident by elevated noise intensity across all frequencies (bright yellow, orange and green bands), which are especially intense in the 10 – 80 Hz frequency range.

In the big, dark ocean, whales use sound to communicate, find food, and navigate. So, let’s try to imagine what it’s like for a whale trying to communicate in an environment with seismic airgun activity. First, let’s listen to a New Zealand blue whale call (vocalization) recorded in the STB. [This audio clip is played at 10X the original speed so that it is more audible to the human hearing frequency range. You can see the real time scale in the top plot.]

Now, let’s look at a spectrogram of seismic airgun pulses and a blue whale call happening at the same time. The seismic airgun blasts are still evident every ~8 seconds, and the blue whale call is also evident at about the 25 Hz frequency (within the pink box). Because blue whales call at such a low frequency humans cannot hear their call when played at normal speed, so you will only hear the airgun pulses if you hit play. But you can see in the spectrogram that five airgun blasts overlapped with the blue whale call.

No doubt this blue whale heard the repetitive seismic airgun blasts, and vocalized in the same frequency range at the same time. Yet, the blue whale’s call was partially drowned out by the intense seismic airgun blasts. Did any other whale hear it? Could this whale hear other whales? Did it get the message across? Maybe, but probably not very well.

Some oil and gas representatives point toward their adherence to seismic survey guidelines and use of marine mammal observers to reduce their impacts on marine life. In New Zealand these guidelines only stop airgun blasting when animals are within 1000 m of the vessel (1.5 km if a calf is present), yet seismic airgun blasts are so intense that the noise travels much farther. So, while these guidelines may be a start, they only prevent hearing damage to whales and dolphins by stopping airguns from blasting right on top of animals.

So, what does this mean for whales and other marine animals living in habitat where seismic airguns are operating? It means their lives are disturbed and dramatically altered. Multiple scientific studies have shown that whales change behavior5, distribution6, and vocalization patterns7 when seismic airguns are active. Other marine life like squid8, spiny lobster9, scallops10, and plankton11 also suffer when exposed to airgun noise. The evidence has mounted. There is no longer a scientific debate: seismic airguns are harmful to marine animals and ecosystems.

What we are just starting to study and understand is the long-term and population level effects of seismic airguns on whales and other marine life. How do short term behavioral changes, movement to different areas, and different calling patterns impact an individual’s ability to survive or a population’s ability to persist? These are the important questions that need to be addressed now.

Seismic airgun surveys to find new oil and gas reserves are so pervasive in our global oceans, that airgun blasts are now heard year round in the equatorial Atlantic3, 12. As reserves shrink on land, the industry expands their search in our oceans, causing severe and persistent consequences to whales, dolphins and other marine life. The oil and gas industry must take ownership of the impacts of their seismic airgun activities. It’s imperative that political, management, scientific, and public pressure force a more complete assessment of each proposed seismic airgun survey, with an honest evaluation of the tradeoff between economic benefits and costs to marine life.

Here are a few ways we can reduce the impact of seismic airguns on marine life and ecosystems:

  • Restrict seismic airgun operation in and near sensitive environmental areas, such as marine mammal feeding and breeding areas.
  • Prohibit redundant seismic surveys in the same area. If one group has already surveyed an area, that data should be shared with other groups, perhaps after an embargo period.
  • Cap the number and duration of seismic surveys allowed each year by region.
  • Promote the use of renewable energy sources.
  • Develop new and quieter survey methods.

Even though we cannot hear the relentless booming, this does not mean it’s not happening and harming animals. Please listen one more time to 1 minute of what whales hear for months during seismic airgun operations.

 

More information on seismic airgun surveys and their impact on marine life:

Boom, Baby, Boom: The Environmental Impacts of Seismic Surveys

A Review of the Impacts of Seismic Airgun Surveys on Marine Life

Sonic Sea: Emmy award winning film about ocean noise pollution and its impact on marine mammals.

Atlantic seismic will impact marine mammals and fisheries

 

References:

  1. Gordon, J., et al., A review of the effects of seismic surveys on marine mammals. Marine Technology Society Journal, 2003. 37(4): p. 16-34.
  2. National Research Council (NRC), Ocean Noise and Marine Mammals. 2003, National Academy Press: Washington. p. 204.
  3. Nieukirk, S.L., et al., Sounds from airguns and fin whales recorded in the mid-Atlantic Ocean, 1999–2009. The Journal of the Acoustical Society of America, 2012. 131(2): p. 1102-1112.
  4. Weilgart, L., A review of the impacts of seismic airgun surveys on marine life. 2013, Submitted to the CBD Expert Workshop on Underwater Noise and its Impacts on Marine and Coastal Biodiversity 25-27 February 2014: London, UK. .
  5. Miller, P.J., et al., Using at-sea experiments to study the effects of airguns on the foraging behavior of sperm whales in the Gulf of Mexico. Deep Sea Research Part I: Oceanographic Research Papers, 2009. 56(7): p. 1168-1181.
  6. Castellote, M., C.W. Clark, and M.O. Lammers, Acoustic and behavioural changes by fin whales (Balaenoptera physalus) in response to shipping and airgun noise. Biological Conservation, 2012. 147(1): p. 115-122.
  7. Di lorio, L. and C.W. Clark, Exposure to seismic survey alters blue whale acoustic communication. Biology Letters, 2010. 6(1): p. 51-54.
  8. Fewtrell, J. and R. McCauley, Impact of air gun noise on the behaviour of marine fish and squid. Marine pollution bulletin, 2012. 64(5): p. 984-993.
  9. Fitzgibbon, Q.P., et al., The impact of seismic air gun exposure on the haemolymph physiology and nutritional condition of spiny lobster, Jasus edwardsii. Marine Pollution Bulletin, 2017.
  10. Day, R.D., et al., Exposure to seismic air gun signals causes physiological harm and alters behavior in the scallop Pecten fumatus. Proceedings of the National Academy of Sciences, 2017. 114(40): p. E8537-E8546.
  11. McCauley, R.D., et al., Widely used marine seismic survey air gun operations negatively impact zooplankton. Nature Ecology & Evolution, 2017. 1(7): p. s41559-017-0195.
  12. Haver, S.M., et al., The not-so-silent world: Measuring Arctic, Equatorial, and Antarctic soundscapes in the Atlantic Ocean. Deep Sea Research Part I: Oceanographic Research Papers, 2017. 122: p. 95-104.

 

 

 

The five senses of fieldwork

By Leila Lemos, PhD student

 

This summer was full of emotions for me: I finally started my first fieldwork season after almost a year of classes and saw my first gray whale (love at first sight!).

During the fieldwork we use a small research vessel (we call it “Red Rocket”) along the Oregon coast to collect data for my PhD project. We are collecting gray whale fecal samples to analyze hormone variations; acoustic data to assess ambient noise changes at different locations and also variations before, during and after events like the “Halibut opener”; GoPro recordings to evaluate prey availability; photographs in order to identify each individual whale and assess body and skin condition; and video recordings through UAS (aka “drone”) flights, so we can measure the whales and classify them as skinny/fat, calf/juvenile/adult and pregnant/non-pregnant.

However, in order to collect all of these data, we need to first find the whales. This is when we use our first sense: vision. We are always looking at the horizon searching for a blow to come up and once we see it, we safely approach the animal and start watching the individual’s behavior and taking photographs.

If the animal is surfacing regularly to allow a successful drone overflight, we stay with the whale and launch the UAS in order to collect photogrammetry and behavior data.

Each team member performs different functions on the boat, as seen in the figure below.

Figure 1: UAS image showing each team members’ functions in the boat at the moment just after the UAS launch.
Figure 1: UAS image showing each team members’ functions in the boat at the moment just after the UAS launch.

 

While one member pilots the boat, another operates the UAS. Another team member is responsible for taking photos of the whales so we can match individuals with the UAS videos. And the last team member puts the calibration board of known length in the water, so that we can later calculate the exact size of each pixel at various UAS altitudes, which allows us to accurately measure whale lengths. Team members also alternate between these and other functions.

Sometimes we put the UAS in the air and no whales are at the surface, or we can’t find any. These animals only stay at the surface for a short period of time, so working with whales can be really challenging. UAS batteries only last for 15-20 minutes and we need to make the most of that time as we can. All of the members need to help the UAS pilot in finding whales, and that is when, besides vision, we need to use hearing too. The sound of the whale’s respiration (blow) can be very loud, especially when whales are closer. Once we find the whale, we give the location to the UAS pilot: “whale at 2 o’clock at 30 meters from the boat!” and the pilot finds the whale for an overflight.

The opposite – too many whales around – can also happen. While we are observing one individual or searching for it in one direction, we may hear a blow from another whale right behind us, and that’s the signal for us to look for other individuals too.

But now you might be asking yourself: “ok, I agree with vision and hearing, but what about the other three senses? Smell? Taste? Touch?” Believe it or not, this happens. Sometimes whales surface pretty close to the boat and blow. If the wind is in our direction – ARGHHHH – we smell it and even taste it (after the first time you learn to close your mouth!). Not a smell I recommend.

Fecal samples are responsible for the 5th sense: touch!

Once we identify that the whale pooped, we approach the fecal plume in order to collect as much fecal matter as possible (Fig.2).

Figure 2: A: the poop is identified; B: the boat approaches the feces that are floating at the surface (~30 seconds); C: one of the team members remains at the bow of the boat to indicate where the feces are; D: another team member collects it with a fine-mesh net. Filmed under NOAA/NMFS permit #16111 to John Calambokidis).
Figure 2: A: the poop is identified; B: the boat approaches the feces that are floating at the surface (~30 seconds); C: one of the team members remains at the bow of the boat to indicate where the feces are; D: another team member collects it with a fine-mesh net. Filmed under NOAA/NMFS permit #16111 to John Calambokidis).

 

After collecting the poop we transfer all of it from the net to a small jar that we then keep cool in an ice chest until we arrive back at the lab and put it in the freezer. So, how do we transfer the poop to the jar? By touching it! We put the jar inside the net and transfer each poop spot to the jar with the help of water pressure from a squeeze bottle full of ambient salt water.

Figure 3: Two gray whale individuals swimming around kelp forests. Filmed under NOAA/NMFS permit #16111 to John Calambokidis).
Figure 3: Two gray whale individuals swimming around kelp forests. Filmed under NOAA/NMFS permit #16111 to John Calambokidis).

 

That’s how we use our senses to study the whales, and we also use an underwater sensory system (a GoPro) to see what the whales were feeding on.

GoPro video of mysid swarms that we recorded near feeding gray whales in Port Orford in August 2016:

Our fieldwork is wrapping up this week, and I can already say that it has been a success. The challenging Oregon weather allowed us to work on 25 days: 6 days in Port Orford and 19 days in the Newport and Depoe Bay region, totaling 141 hours and 50 minutes of effort. We saw 195 whales during 97 different sightings and collected 49 fecal samples. We also performed 67 UAS flights, 34 drifter deployments (to collect acoustic data), and 34 GoPro deployments.

It is incredible to see how much data we obtained! Now starts the second part of the challenge: how to put all of this data together and find the results. My next steps are:

– photo-identification analysis;

– body and skin condition scoring of individuals;

– photogrammetry analysis;

– analysis of the GoPro videos to characterize prey;

– hormone analysis laboratory training in November at the Seattle Aquarium

 

For now, enjoy some pictures and a video we collected during the fieldwork this summer. It was hard to choose my favorite pictures from 11,061 photos and a video from 13 hours and 29 minutes of recording, but I finally did! Enjoy!

Figure 4: Gray whale breaching in Port Orford on August 27th. (Photo by Leila Lemos; Taken under NOAA/NMFS permit #16111 to John Calambokidis).
Figure 4: Gray whale breaching in Port Orford on August 27th. (Photo by Leila Lemos; Taken under NOAA/NMFS permit #16111 to John Calambokidis).

 

Figure 5: Rainbow formation through sunlight refraction on the water droplets of a gray whale individual's blow in Newport on September 15th. (Photo by Leila Lemos; Taken under NOAA/NMFS permit #16111 to John Calambokidis).
Figure 5: Rainbow formation through sunlight refraction on the water droplets of a gray whale individual’s blow in Newport on September 15th. (Photo by Leila Lemos; Taken under NOAA/NMFS permit #16111 to John Calambokidis).

 

Likely gray whale nursing behavior (Taken under NOAA/NMFS permit #16111 to John Calambokidis):

Unmanned Aircraft Systems: keep your distance from wildlife!

By Leila Lemos, Ph.D. Student, Department of Fisheries and Wildlife, OSU

Unmanned aircraft systems (UAS) or “drones” are becoming commonly used to observe natural landscapes and wildlife. These systems can provide important information regarding habitat conditions, distribution and abundance of populations, and health, fitness and behavior of the individuals (Goebel et al. 2015, Durban et al. 2016).

The benefits for the use of UAS by researchers and wildlife managers are varied and include reduced errors of population estimations, reduced observer fatigue, increased observer safety, increased survey effort, and access to remote settings and harsh environments (Koski et al. 2010, Vermeulen et al. 2013, Goebel et al. 2015, Smith et al. 2016). Importantly, data gathered from UAS can provide needed information for the conservation and management of several species. Although it is often assumed that wildlife incur minimal disturbance from UAS due to the reduced noise compared to traditional aircraft used for wildlife monitoring (Acevedo-Whitehouse et al. 2010), the impacts of UAS on most wildlife populations is currently unexplored.

Several studies have tried to comprehend the effects of UAS flights over animals and so far there is no evidence of behavioral disturbance. For instance Vermeulen et al. (2013) conducted a study where authors observed a group of elephants’ reaction or warning behavior while a UAS passed ten times over the individuals at altitudes of 100 and 300 meters, and no disturbance was recorded. Furthermore, a study conducted by Acevedo-Whitehouse et al. (2010) reported that six different species of large cetaceans (Bryde’s whale, fin whale, sperm whale, humpback whale, blue whale and gray whale) did not display avoidance behavior when approached by the UAS for blow sampling, suggesting that the system caused minimal distress (negative stress) to the individuals.

However, the fact that we cannot visually see an effect in the animal does not mean that a stress response is not occurring. A study analyzed the effects of UAS flights on movements and heart rate responses of American black bears in northwestern Minnesota (Ditmer et al. 2015). It was observed that all bears, including an individual that was hibernating, responded to UAS flights with increased heart rates (123 beats per minute above the pre-flight baseline). In contrast, no behavioral response by the bears was recorded (Figure 1).

By Leila Lemos, Ph.D. Student, Department of Fisheries and Wildlife, OSU Unmanned aircraft systems (UAS) or “drones” are becoming commonly used to observe natural landscapes and wildlife. These systems can provide important information regarding habitat conditions, distribution and abundance of populations, and health, fitness and behavior of the individuals (Goebel et al. 2015, Durban et al. 2016). The benefits for the use of UAS by researchers and wildlife managers are varied and include reduced errors of population estimations, reduced observer fatigue, increased observer safety, increased survey effort, and access to remote settings and harsh environments (Koski et al. 2010, Vermeulen et al. 2013, Goebel et al. 2015, Smith et al. 2016). Importantly, data gathered from UAS can provide needed information for the conservation and management of several species. Although it is often assumed that wildlife incur minimal disturbance from UAS due to the reduced noise compared to traditional aircraft used for wildlife monitoring (Acevedo-Whitehouse et al. 2010), the impacts of UAS on most wildlife populations is currently unexplored. Several studies have tried to comprehend the effects of UAS flights over animals and so far there is no evidence of behavioral disturbance. For instance Vermeulen et al. (2013) conducted a study where authors observed a group of elephants’ reaction or warning behavior while a UAS passed ten times over the individuals at altitudes of 100 and 300 meters, and no disturbance was recorded. Furthermore, a study conducted by Acevedo-Whitehouse et al. (2010) reported that six different species of large cetaceans (Bryde’s whale, fin whale, sperm whale, humpback whale, blue whale and gray whale) did not display avoidance behavior when approached by the UAS for blow sampling, suggesting that the system caused minimal distress (negative stress) to the individuals. However, the fact that we cannot visually see an effect in the animal does not mean that a stress response is not occurring. A study analyzed the effects of UAS flights on movements and heart rate responses of American black bears in northwestern Minnesota (Ditmer et al. 2015). It was observed that all bears, including an individual that was hibernating, responded to UAS flights with increased heart rates (123 beats per minute above the pre-flight baseline). In contrast, no behavioral response by the bears was recorded (Figure 1).
Figure 1: (A) Movement rates (meters per hour) of an adult female black bear with cubs prior to, during, and after a UAS flight (gray bar); (B) The corresponding heart rate (beats per minute) of the adult female black bear. Source: Modified from Figure 1 from Ditmer et al. 2015.

 

Therefore, behavioral analysis alone may not be able to describe the complete effects of UAS on wildlife, and it is important to consider other possible stress responses of wildlife.

Regarding marine mammals, only a few studies have systematically documented the effects of UAS on these animals. A review of these studies was produced by Smith et al. (2016) and the main factors influencing behavioral disturbance were identified as (1) noise and visual stimulus (from the UAS or its shadow), and (2) flight altitude of the UAS. Thus, studies that approach marine mammals closely with UAS (e.g., blow sampling in cetaceans) should be closely monitored for behavioral reactions because the noise level and visual stimulus will likely be increased.

Fortunately, when UAS work is applied to cetaceans and sirenians (manatees and dugongs) the air-water interface acts as a barrier to sound so these animals are unlikely to be acoustically disturbed by UAS. However, acoustic detection and response are still possible when an animal’s ears are exposed in the air during a surfacing event.

The best way to minimize stress responses in wildlife is to use caution while operating UAS at any altitude. According to National Oceanic and Atmospheric Administration (NOAA), “UAS can also be disruptive to both people and animals if not used safely, appropriately, or responsibly”. Therefore, since 2012, the Federal Aviation Administration (FAA) has required UAS operators in the United States to have a certified and registered aircraft, a licensed pilot, and operational approval, known as Section 333 Exemption (Note: in late August 2016, the 333 will be replaced by a revision to part 107). These authorizations require an air worthiness statement or certificate and registered aircraft. Public entities, like Oregon State University, operate under a certificate of authorization (COA.) As a public entity OSU certifies its own aircraft and sets standards for UAS operators. These permit requirements discourage illegal operations and improves safety.

Regarding marine mammals, all UAS operators should also be aware of The Marine Mammal Protection Act (MMPA) of 1972. This law makes it illegal to harass marine mammals in the wild, which may cause disruption to behavioral patterns, including, but not limited to, migration, breathing, nursing, breeding, feeding, or sheltering. A close UAS approach has the potential to cause harassments to marine mammals, thus federal guidelines recommend keeping a safe distance from these animals in the wild. The required vertical distance is 1000 ft for most marine mammals, but increases for endangered animals such as the North Atlantic right whales with a required buffer of 1500 ft (http://www.nmfs.noaa.gov/pr/uas.html). Therefore, NOAA evaluates all scientific research that use UAS within 1000 ft of marine mammals in order to ensure that the benefits outweigh possible hazards. NOAA distributes research permits accordingly.

Of course, with new technology the rules are always changing. In fact, last week the Department of Transportation (DOT) and the FAA finalized the first operational rules for routine commercial use of small UAS. These new guidelines aim to support new innovations in order to spur job growth, advance critical scientific research and save lives, and are designed to minimize risks to other aircraft and people and property on the ground. These new regulations include several requirements (e.g., height and speed restrictions) and hopefully allow for a streamlined system that enables beneficial and exciting wildlife research.

For my PhD project we are using UAS to collect aerial images from gray whales in order to describe behavioral patterns and apply a photogrammetry methodology. Through these methods we will determine the overall body condition and health of the individuals for comparison to variable ambient ocean noise levels. This project is conducted in collaboration with the NOAA Pacific Marine Environmental Lab.

Since October 2015, we have conducted 31 over-flights of gray whales using our UAS (DJI Phantom 3) and no behavioral disturbance has been observed. When over the whale(s) we generally fly between 25 and 40 m above the animals. We have a FAA certified UAS operator and fly under our NOAA/NMFS permit 16111. Prior to each flight we ensure that the weather conditions are safe, the whales are behaving normally, and that no on-lookers from shore or other boats will be disturbed.

Here is a video showing the launch and retrieval of the UAS system, our research vessel, the surrounding Oregon coastline beauty and gray whale individuals. The video includes some interesting footage of a gray whale foraging over a shallow reef, indicating that this UAS flight did not disturb the animal’s natural behavior patterns.

We all have the responsibility to help keep wildlife safe. Here in the GEMM Lab, we commit to using UAS safely and responsibly, and aim to use this new and exciting technology to continue our efforts to better protect and understand marine mammals.

 

References

Acevedo‐Whitehouse K, Rocha‐Gosselin A and Gendron D. 2010. A novel non‐invasive tool for disease surveillance of free‐ranging whales and its relevance to conservation programs. Anim. Conserv. 13(2):217–225.

Ditmer MA, Vincent JB, Werden LK, Tanner JC, Laske TG, Iaizzo PA, Garshelis DL and Fieberg JR. 2015. Bears Show a Physiological but Limited Behavioral Response to Unmanned Aerial Vehicles. Current Biology 25:2278–2283.

Durban JW, Moore MJ, Chiang G, Hickmott LS, Bocconcelli A, Howes G, Bahamonde PA, Perryman WL and Leroi DJ. 2016. Photogrammetry of blue whales with an unmanned hexacopter. Marine Mammal Science. DOI: 10.1111/mms.12328.

Goebel ME, Perryman WL, Hinke JT, Krause DJ, Hann NA, Gardner S and LeRoi DJ. 2015. A small unmanned aerial system for estimating abundance and size of Antarctic predators. Polar Biol. 38(5):619-630.

Koski WR, Abgrall P and Yazvenko SB. 2010. An inventory and evaluation of unmanned aerial systems for offshore surveys of marine mammals. J. Cetacean Res. Manag. 11(3):239–247.

NOAA. Unmanned Aircraft Systems: Responsible Use to Help Protect Marine Mammals. In: http://www.nmfs.noaa.gov/pr/uas.html. Accessed in: 06/12/2016.

Smith CE, Sykora-Bodie ST, Bloodworth B, Pack SM, Spradlin TR and LeBoeuf NR. 2016. Assessment of known impacts of unmanned aerial systems (UAS) on marine mammals: data gaps and recommendations for researchers in the United States1 J. Unmanned Veh. Syst. 4:1–14.

Vermeulen C, Lejeune P, Lisein J, Sawadogo P and Bouché P. 2013. Unmanned aerial survey of elephants. PLoS One. 8(2):e54700.

 

SeaBASS 2016

By Samara Haver, MSc student, OSU Fisheries and Wildlife, ORCAA Lab

As a graduate student in bioacoustics (the study of noise produced by biological sources), my education is interdisciplinary. Bioacoustics is a relatively small field, and (together with my peers) I am challenged to find my way through coursework in ecology, physiology, physics, oceanography, statistics, and engineering to learn the background information that I need to develop and answer research questions (since this is my first post for the GEMM lab, here is a little more information about my interests). While this challenge (for all young bioacousticians) presents itself a little differently at all universities, the information gap is essentially the same. Hence, just over 6 years ago, Dr. Jennifer Missis-Old and Dr. Susan Parks recognized a need to fill this gap for graduate students in bioacoustics and created SeaBASS, a BioAcoustics Summer School.

This year, for the 4th iteration of the week-long program, I was lucky to have the opportunity to attend SeaBASS. I first heard about SeaBASS as a research assistant in Dr. Sofie Van Parijs’s passive acoustics group at the Northeast Fisheries Science Center, but the workshop is limited to graduate students only so I had to wait until I was officially enrolled in grad school to apply. My ORCAA lab-mates, Niki, Selene, and Michelle are all alumni of SeaBASS (read Miche’s re-cap from 2014 here ) so by the time I was preparing for my trip to upstate NY this summer to attend, I had a pretty good idea of what was to come.

As expected, the week was packed. I flew to the East Coast a few days early to visit our fearless ORCAA leader, Holger, at the Bioacoustics Research Program at the Cornell Lab of Ornithology, so I was lucky to be somewhat adjusted to EST by the time I arrived at Syracuse on Sunday afternoon. After exploring the campus, it was time for official SeaBASS programming to begin. Our first class, an “Introduction to Acoustics and Proportion”, began early on Monday morning. In the afternoon and through the rest of the week we also learned about active acoustics (creating a sound in the water and using the echo to detect animals or other things) and marine mammal physiology, echolocation, communication, and behavior. We also heard about passive acoustics (listening to existing underwater sounds), including the different types of technology being used and its application for population density estimation. On Friday afternoon, the final lecture covered the effects of noise on marine mammals.

Samara1 Some SeaBASS-ers testing the hypothesis that humans are capable of echolocation.

In addition to the class lectures given by each instructor, we also heard individual opinions about “hot topics” in bioacoustics. This session was my favorite part of the week because we (the students) had the opportunity to hear from a number of accomplished scientists about what they believe are the most pressing issues in the field. Unlike a conference or seminar, these short talks introduced (or reinforced) ideas from researchers in an informal setting, and among our small group it was easy to hear impressions from other SeaBASS-ers afterwards. As a student I spend a lot of my time working alone; my ORCAA labmates are focused on related acoustic projects, but we do not overlap completely. The best part of SeaBASS was sharing ideas, experiences, and general camaraderie with other students that are tackling questions very similar to my own.

Samara2 SeaBASS 2016

Although a full week of class would be plenty to take in by itself, our evenings were also filled with activities. We (students) shared posters (this was mine ) about our individual research projects, listened to advice about life as a researcher in the field, attended a Syracuse Chiefs baseball game, and at the end of each day reflected on our new knowledge and experiences over pints. So, needless to say, I returned home to Oregon completely exhausted, but also with refreshed excitement about my place in the small world of bioacoustics research.

Samara3 Luckily we had beautiful weather for the baseball game!

Samara4

 

Sonic Sea asks “can we turn down the volume before it’s too late?”

By: Amanda Holdman, MS student, Geospatial Ecology and Marine Megafauna Lab & Oregon State Research Collective for Applied Acoustics, MMI

It was March 15th, 2000; Kenneth Balcomb was drinking coffee with his new summer interns in the Bahamas when a goose-beaked whale stranded on a nearby beach. Balcomb, a whale researcher and former U.S. Navy Officer, gently pushed the whale out to sea but the beaked whale kept returning to the shore. He continued this process until a second beaked whale stranding was reported further down the beach; and then a third. Within hours, 17 cetaceans had stranded in the Bahamas trying to escape ‘something’ in the water, and Kenneth Balcomb was determined to solve the mystery of the mass stranding. The cause, he eventually learned, was extreme noise – sonar tests from Navy Warships.

The world is buzzing with the sounds of Earth’s creatures as they are living, interacting, and communicating with one another, even in the darkest depths of the oceans. Beneath the surface of our oceans lies a finely balanced, living world of sound. To whales, dolphins and other marine life, sound is survival; the key to how they navigate, find mates, hunt for food, communicate over vast distances and protect themselves against predators in waters dark and deep. Yet, this symphony of life is being disrupted and sadly destroyed, by today’s increasing noise pollution (Figure 1). Human activities in the ocean have exploded over the past 5 decades with ocean noise rising by 3db per decade (Halpern et al. 2008). People have been introducing more and more noise into the ocean from shipping, seismic surveys for oil and gas, naval sonar testing, renewable energy construction, and other activities. This increased noise has significant impacts on acoustically active and sensitive marine mammals. However, as the Discovery Chanel’s new documentary Sonic Sea points out “The biggest thing about noise in the ocean is that humans aren’t aware of the sound at all.” The increase of ocean noise has transformed the delicate ocean habitat, and has challenged the ability of whales and other marine life to prosper and survive.

June blogFigure 1: Anthropogenic sources contributing to ocean soundscapes and the impacts on marine megafauna survival (sspa.se)

Like the transformative documentary from 10 years ago, An Inconvenient Truth, which highlighted the reality and dangers of climate change, Sonic Sea aims to inform audiences of increased man-made noise in the oceans and the harm it poses to marine animals. The Hatfield Marine Science Center and Oregon Chapter of the American Cetacean Society offered a free, premier showing of the award-winning documentary followed by a scientific panel discussion. The panel featured Dave Mellinger, Joe Haxel, and Michelle Fournet of Oregon State University’s Cooperative Institute for Marine Resources Studies (CIMRS) marine bioacoustics research along with GEMM Lab leader, Leigh Torres, of the Marine Mammal Institute.

Sonic Sea introduces us to this global problem of ocean noise and offers up solutions for change. The film uncovers how better ship design, speed limits for large ships, quieter methods for under water resource exploration, and exclusion zones for sonar training can work to reduce the noise in our oceans. However, these efforts require continued innovation and regulatory involvement to bring plans to action.

Around the world the scientific community, policymakers and authorities such as The National Oceanic and Atmospheric Administration (NOAA), the European Union (EU), the International Maritime Organization (IMO) and other authorities have increasingly pressed for the reduction of noise.  NOAA, which manages and protects marine life in United States waters, is trying to reduce ocean noise through their newly released Ocean Noise Strategy Roadmap, where the challenge is dealt with as a comprehensive issue rather than a case-by-case basis. This undersea map is a 10-year plan that aims to identify areas of specific importance for cetaceans and the temporal, spatial, and frequency of man-made underwater noise. After obtaining a more comprehensive scientific understanding of the distributions and effects of noise in the ocean, these maps can help to develop better tools and strategies for the management and mitigation of ocean noise.

Sonic Sea states “we must protect what we love” but then asks “how we can love it if we don’t understand it?” Here at GEMM Lab and the Marine Mammal Institute, we are trying to understand marine species ecology, distributions and behavioral responses to anthropogenic impacts. One of the suggestions Sonic Sea makes to reduce the impact of ocean noise is to restrict activity in biologically sensitive habitats. Therefore, we must know where these important areas are. In an ideal world, we would have a good inventory of data on the marine animals present in a region and when these animals breed, birth and feed. Then we could use this information to guide marine spatial planning and management to keep noise out of important habitats. My thesis project aims to provide such baseline information on harbor porpoise distribution patterns within a proposed marine energy development site. By filling knowledge gaps about where marine animals can be found and why certain habitats are critical, conservation efforts can be more directed and effective in reducing threats, such as ocean noise, to marine mammals.

Noise in our oceans is hard to observe, but its effects are visibly traumatic and well-documented. Unlike other sources of pollution to our oceans, (climate change, acidification, plastic pollution), which may take years, decades or centuries to dissipate, reducing ocean noise is rather straight forward. “Like a summer night when the fireworks end, our oceans can quickly return to their natural soundscape.” Ocean noise is a problem we can fix. To quiet the world’s waters, we all need to raise our voices so policy makers hear of this problem. That’s what Sonic Sea is all about: increasing awareness of this growing threat and building a worldwide community of citizen advocates to help us turn down the volume on undersea noise. If we sit back and do nothing to mitigate oceanic noise pollution, the problem will likely worsen. I highly suggest watching Sonic Sea.  Then, together, we can speak up to turn down the noise that threatens our oceans — and threatens us all.

Sonic Sea airs TONIGHT (6/8) for World Ocean’s Day on Animal Planet  at 10pm ET/PT!

An update on Oregon’s sound sensitive marine mammal, the harbor porpoise.

By Amanda Holdman, M.S. Student

Marine renewable energy is developing at great speeds all around the world. In 2013, the Northwest Marine Renewable Energy Center (NMREC) chose Newport, Oregon as the future site of first utility-scale, grid-connected wave energy test site in the United States – The Pacific Marine Energy Center (PMEC). The development of marine energy holds great potential to help meet our energy needs – it is renewable, and it is predicted that marine energy sources could fulfill nearly one-third of the United States energy demands.

Wave energy construction in Newport could begin as early as 2017. Therefore, it is important to fully understand the potential risks and benefits of wave energy as the industry moves forward. Currently, there is limited information on wave energy devices and the potential ecological impacts that they may have on marine mammals and their habitats. In order to assess the effects of wave energy, pertinent information needs to be collected prior to the installation of the devices.

This is where I contribute to the wave energy industry in Oregon.

Harbor porpoise are a focal species when it comes to renewable energy management; they are sensitive to a range of anthropogenic sounds at very low levels of exposure and may show behavioral responses before other marine mammals, making them a great indicator species for potential problems with wave energy. Little is known about harbor porpoise in Oregon, necessitating the need to look at the fine scale habitat use patterns of harbor porpoise within the proposed wave energy sites.

I used two methods to study harbor porpoise presence and activity in coastal waters: visual boat surveys, and passive acoustic monitoring. Visual surveys have a high spatial resolution and a low temporal resolution, meaning you can conduct visual boat surveys over a wide area, but only during daylight hours. Whereas acoustic surveys have opposite characteristics; you can conduct surveys during all hours of the day, however, the range of the acoustic device is only a few hundred meters. Therefore, these methods work well together to gain complimentary information about harbor porpoise. These methods are crucial for collecting baseline data on harbor porpoise distribution, and providing valuable information for understanding, managing, and mitigating potential impacts.

Bi-monthly standard visual line-transect surveys were conducted for two full years (October 2013-2015), while acoustic devices were deployed May – October 2014. Field work ended last October, and since then, data analysis efforts have uncovered  seasonal, diel, and tidal patterns in harbor porpoise occurrence and activity.

Harbor porpoises in Oregon are thought to be seasonally migratory. With the onset of spring, coinciding with the start of the upwelling season, porpoise are thought to move inshore and abundance increases into the summer. Most births also occur during the late spring and summer. With the return of winter, porpoise are thought to leave the coastal waters and head out to the deeper waters (Dohl 1983, Barlow 1988, Green et al. 1992).

Results from my data support this seasonal trend. Both visual survey and acoustic recording data document the general pattern of peak porpoise presence occurring in the summer months of June and July, with a gradual decline of detections into the fall (Fig. 1 & 2).

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Figure 1: Overall, from our acoustic surveys we see a large increase from May to June, suggesting the arrival of harbor porpoise to coastal waters. From July, we see a slow decline into the fall months, suggestive of harbor porpoise moving offshore.

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Figure 2: Our data from visual surveys mimic those of our acoustic surveys. We see a large increase of porpoises from May to June and then a decline into the fall. We had very low survey effort in July, due to rough seas.  If we were able to survey more, it is likely we would have seen more harbor porpoise during this time.

Using acoustic recorders, we are able to get data on harbor porpoise occurrence throughout all hours of the day, regardless of weather conditions. We deployed hydrophones in two locations – one in a near-shore REEF habitat located 4 km from shore, and the second in the middle of the South Energy Testing Site (SETS) 12 km off-shore. These two sites differ in depth and habitat type. The REEF habitat is 30 m deep and has a rocky bottom as a habitat type, while SETS is 60 m deep and has a sandy bottom. When we compare the two sites (Figure 3), we can see that harbor porpoise have a preference for the REEF site.

Additionally, we are also able to get some indices of behavior from acoustic recordings. Equivalent to sonar or radar, marine mammals use echolocation (high frequency sounds) to communicate and navigate. Marine mammals, specifically odonotocetes, also use echolocation to locate prey at depth when there is very little or no light. Porpoises use a series of clicks during their dives, and as the porpoise approach their prey, the clicks become closer and closer together so they sound like a continuous buzz. When studying echolocation patterns in odontocetes we typically look at the inter-click-intervals (ICIs) or the time between clicks. When ICIs are very close together (less than 10 ms apart) it is considered a foraging behavior or a buzz. Anything greater than 10 ms is classified as other (or clicks in this figure).

Click_Buzz_bargraph.

Figure 3: We see harbor porpoise clicks were detected about 27% of the time at the REEF, but only 18% at SETS. Potential feeding was also higher at the REEF site (14%) compared to (4%) at SETS.

Not only did we find patterns in foraging behavior between the two sites, we also found foraging patterns across diel cycles and tidal cycles:

  1. We found a tendency for harbor porpoise to forage more at night (Figure 4).
  2. The diel pattern of harbor porpoise foraging is stronger at the SETS than the REEF site (Figure 4). This result may be due to the prey at the SETS (sandy bottom) exhibiting vertical migration with the day and night cycles since prey there do not have alternative cover, as they would in the rocky reef habitat.
  3. At the reef site, we see a relationship between increased foraging behavior and low tide (Figure 5).

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Figure 4: When analyzing data for trends in foraging behavior across different sites and diel cycles, we use a ratio of buzzes to clicks, so that we incorporate both echolocation behaviors in one value. This figure shows us that the ratio of buzzes to clicks is pretty similar at the REEF site across diel periods, but there is more variation at the SETS site, with more detections at night and during sunrise.

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Figure 5: Due to the circular nature of tides rotating between high tide and low tide, circular histograms help to observe patterns. In this figure, we see a large preference for harbor porpoise to feed during low tide. We are unclear why harbor porpoise may prefer low tide, but the relationship may be due to minimal current movement that could enhance feeding opportunities for porpoises.

Overall, the combination of visual surveys and passive acoustic monitoring has provided high quality baseline data on harbor porpoise occurrence patterns. It is results like these that can help with decisions regarding wave energy siting, operation and permitting off of the Oregon Coast.

REFERENCES

Barlow, J. 1987. Abundance estimation for harbor porpoise (Phocoena phocoena) based on ship surveys along the coasts of California, Oregon and Washington. SWFC Administrative Report LJ-87-05. Southwest Fishery Center, La Jolla, CA. 36pp.

Dohl, T.P., Guess, R.C., Dunman, M.L. and Helm, R.C. 1983, Cetaceans of central and northern California, 1980-83: status, abundance, and distribution. Final Report to the Minerals Management Service, Contract 14-12-0001-29090. 285pp.

Green, G.A., Brueggeman, J. J., Grotefendt, R.A., Bowlby, C.E., Bonnel, M. L. and Balcomb, K.C. 1992. Cetacean distribution and abundance off Oregon and Washington, 1989-1990. Chapter 1 In Oregon and Washington Marine Mammal and Seabird Surveys. Ed. By J. J. Brueggeman. Minerals Management Service Contract Report 14-12-0001-30426.

Eavesdropping on blue whales in New Zealand

 

Kristin Brooke Hodge

Research Analyst, Bioacoustics Research Program, Cornell University

https://www.researchgate.net/profile/Kristin_Hodge

Over the past few weeks, we have surveyed the South Taranaki Bight, New Zealand, collecting biological and oceanographic data to learn more about the population of blue whales in this region.  Our efforts have been successful: we have encountered multiple blue whales, and recorded information about their identification, behavior, and habitat.  While our visual survey efforts have provided us with an invaluable dataset, our field season is shortly coming to an end.  So how can we continue to learn more about the blue whale population, if we cannot collect visual survey data?

Solution: we will study the sounds they make.

Bioacoustics is a non-invasive method to study acoustically-active animal populations in terrestrial and marine habitats.  Scientists can eavesdrop on animals by recording and analyzing their sounds, and in turn gain insights about their occurrence, behavior, and movement patterns.   This is especially useful for studying elusive or rare species, such as the blue whale, that can be difficult to find in the field.  Since blue whales produce high intensity, infrasonic calls and songs that can travel for many miles across ocean basins, we can capture information regarding their spatial and temporal occurrence, even if we cannot see them. (To listen to a blue whale call recorded off of Chile click here.)

We are using Marine Autonomous Recording Units (MARUs), developed by the Cornell Bioacoustics Research Program, to record blue whales (Fig. 1).  The MARU is a digital audio recording system contained in a buoyant sphere, which is deployed on the bottom of the ocean using an anchor.  Each MARU has a hydrophone that collects acoustic data, and these sounds are recorded and stored on electronic storage media inside the MARU.  The MARUs are programmed to record continuous, low-frequency sounds for approximately six months, after which they pop up to the surface of the ocean, ready to be retrieved for data analysis and redeployed with fresh batteries and storage media.

Figure 1. Kristin Hodge about to deploy a Marine Autonomous Recording Unit (MARU) and anchors in the South Taranaki Bight of New Zealand.
Figure 1. Kristin Hodge about to deploy a Marine Autonomous Recording Unit (MARU) and anchors in the South Taranaki Bight of New Zealand.

Over the course of this field season, we strategically deployed five MARUs across the South Taranaki Bight (Fig. 2), and we will record acoustic data in these five sites over the next couple of years.  This will allow us to understand patterns of occurrence at larger spatial and temporal scales than we can accomplish with visual survey alone.  Our acoustic dataset will complement the biological and oceanographic data we collected on survey, providing a more complete picture of the blue whale population in the bight.

Figure 2. Approximate locations of Marine Autonomous Recording Unit (MARU) deployment sites across the South Taranaki Bight of New Zealand.
Figure 2. Approximate locations of Marine Autonomous Recording Unit (MARU) deployment sites across the South Taranaki Bight of New Zealand.

To see us deploy a MARU in New Zealand, check out this video: