By Dawn Barlow, MSc student, Department of Fisheries and Wildlife, Geospatial Ecology of Marine Megafauna Lab
In 2013, Leigh first published a hypothesis that the South Taranaki Bight region between New Zealand’s North and South Islands is important habitat for blue whales (Torres 2013). Since then, we have collected three years of data and conducted dedicated analyses, so we now understand that a unique population of blue whales is found in New Zealand, and that they are present in the South Taranaki Bight year-round (Barlow et al. in press).
A blue whale surfaces in the South Taranaki Bight. Photo by Leigh Torres.
This research has garnered quite a bit of political and media attention. A major platform item for the New Zealand Green Party around the last election was the establishment of a marine mammal sanctuary in the South Taranaki Bight. When the world’s largest seismic survey vessel began surveying the South Taranaki Bight this summer for more oil and gas reserves using tremendously loud airguns, there were rallies on the lawn in front of Parliament featuring a large inflatable blue whale that the protesters affectionately refer to as “Janet”. Needless to say, blue whales have made their way into the spotlight in New Zealand.
Janet the inflatable blue whale accompanies protesters on the lawn in front of Parliament in Wellington, New Zealand. Image credit: Greenpeace.
Now that we know there is a unique population of blue whales in New Zealand, what is next? What’s next for me is an exciting combination of both ecology and conservation. If an effective sanctuary is to be implemented, it needs to be more than a simple box drawn on a map to check off a political agenda item—the sanctuary should be informed by our best ecological knowledge of the blue whales and their habitat.
In July, Leigh and I will attend the Society for Conservation Biology meeting in Wellington, New Zealand, and I’ll be giving a presentation titled “Cloudy with a chance of whales: Forecasting blue whale presence based on tiered, bottom-up models”. I’ll be the first to admit, I am not yet forecasting blue whale presence. But I am working my way there, step-by-step, through this tiered, bottom-up approach. In cetacean habitat modeling, we often assume that whale distribution on a foraging ground is determined by their prey’s distribution, and that satellite images of temperature and chlorophyll-a provide an accurate picture of what is going on below the surface. Is this true? With our three years of data including in situ oceanography, krill hydroacoustics, and blue whale distribution and behavior, we are in a unique position to test some of those assumptions, as well as provide managers with an informed management tool to predict blue whale distribution.
What questions will we ask using our data? Firstly, can in situ oceanography (i.e., thermocline depth and temperature, mixed layer depth) predict the distribution and density of blue whale prey (krill)? Then, can those prey patterns be accurately predicted in the absence of oceanographic measurements, using just satellite images? Next, we’ll bring the blue whales back into the picture to ask: can we predict blue whale distribution based on our in situ measurements of oceanography and prey? And finally, in the absence of in situ measurements (which is most often the case), can we forecast where the whales will be based just on remotely-sensed images of the region?
The transducer pole in the water off the RV Star Keys (left) deployed with the echosounder to collect prey availability data, including this image (right) of krill swarms near feeding blue whales. Photo by Leigh Torres.
So, cloudy with a chance of whales? Well, you’ll have to stay tuned for that story in the coming months. In the meantime, I can tell you that as daunting as it is to aggregate so many data streams, each step of the way has a piece of the story to tell. I can’t wait to see how it falls together, both from an ecological modeling perspective and a conservation management objective.
A blue whale surfaces in front of a floating production storage and offloading (FPSO) vessel which services the oil rigs in the South Taranaki Bight. Photo by Dawn Barlow.
References:
Torres, L. G. (2013). Evidence for an unrecognised blue whale foraging ground in New Zealand. New Zealand Journal of Marine and Freshwater Research, 47(2), 235-248.
Barlow, D. R., Torres, L. G., Hodge, K. B., Steel, D. Baker, C. S., Chandler, T. E., Bott, N., Constantine, R., Double, M. C., Gill, P., Glasgow, D., Hamner, R. M., Lilley, C., Ogle, M., Olson, P. A., Peters, C., Stockin, K. A., Tessaglia-Hymes, C. T., Klinck, H. (in press). Documentation of a New Zealand blue whale population based on multiple lines of evidence. Endangered Species Research.
By Dawn Barlow, MSc student, Department of Fisheries and Wildlife
A few weeks ago, my labmate Dom’s blog reminded me that it is important to step back from the data and appreciate the magnificence of the animals we study from time to time. I have the privilege of studying the largest creatures on the planet. When people hear that I study blue whales, I often get a series of questions: Just how big are they, really? How many are there? Where do they migrate? Where do they breed? Despite the fact that humans hunted blue whales nearly to extinction [1,2], we still know next to nothing about these giants. The short answer to many of those questions is, “Well we don’t really know, but we’re working on it!” Which brings me back to taking time to marvel at these animals for a bit. Isn’t it remarkable that the largest animals on earth can be so mysterious?
A blue whale comes up for air in a calm sea. Photo by Leigh Torres.
Last year at this time we were aboard a research vessel in New Zealand surveying for blue whales and collecting a myriad of biological data to try and glean some insight into their lives. This winter I am processing those data and conducting a literature review to get a firm grasp on what others have found before about blue whale foraging and bioenergetics. On any given Tuesday morning Leigh and I can be found musing about the mechanics of a baleen whale jaw, about what oceanographic boundaries in the water column might be meaningful to a blue whale, about how we might quantify the energy expenditure of a foraging whale. Here are some of those musings.
Approaching a blue whale in a rigid-hull inflatable boat for data collection. UAS piloted by Todd Chandler.
Humans are, for the most part, terrestrial creatures. Even those of us that would prefer to spend most of our time near, on, or in the water are limited in what we can observe of marine life. Much of the early data that was collected on blue whales came from whaling catches. Observations of anatomy and morphology were made once the whales were killed and taken out of their marine environment. This was not long ago—Soviet whaling continued into the 1970’s in New Zealand [3]. Because baleen whales are long lived (exact age unknown for blue whales but a bowhead whale was estimated to be at least 150 years old [4]) it is entirely possible that blue whales living today remember being hunted by whalers. Observing whales in their natural state is not easy, particularly post-commercial whaling when they are few and far between.
Yet, where there is a challenge, clever people develop creative approaches and new technologies, leading to new insights. High-quality cameras have allowed scientists to photograph whales for individual identification—a valuable first step in figuring out how many there are and where they go [5]. Satellite tags have allowed scientists to track the movement of blue whales in the North Pacific and Indian Oceans, a first step in learning where these whales might go to breed. However, no blue whale breeding ground has definitively been discovered yet…
What does a whale do when it is below the surface, out of sight of our terrestrial eyes? A study from 1986 that attempted to calculate the prey demands of a whale assumed that whenever a whale was submerged, it was feeding [6]. A big assumption, but a starting place without any dive data. By 2002, tags equipped with time-depth recorders (TDR) had already revealed that blue whales make dives of variable depths and shapes [7]. But, what determines a whale’s path underwater, where they must conserve as much oxygen as they can while finding and exploiting patches of prey? The advent of digital acoustic recording tags (DTAGs) in the early 2000s have allowed scientists to measure the fine-scale movements of whales in three dimensions [8]. These tags can capture the kinematic signatures (based on pitch, roll, and yaw) of lunge-feeding events below the surface. And with the addition of echosounder technology that allows us to map the prey field, we can now link feeding events with characteristics of the prey present in the area [9]. With this progression of technology, curiosity and insight we now know that blue whales are not indiscriminate grazers, but instead pass up small patches of krill in favor of large, dense aggregations where they will get the most energetic bang for their buck.
A blue whale shows its fluke as it dives deep in an area with abundant krill deep in the water column. Photo by L. Torres.
The advent of unmanned aerial systems (UAS, a.k.a. “drones”) have provided yet another unique perspective on the lives of these whales. In 2016, our New Zealand blue whale team recorded nursing behavior between a mother and calf. In 2017, we were able to capture surface lunge feeding behavior from an aerial perspective, both for the first time.
A blue whale lunges on an aggregation of krill. UAS piloted by Todd Chandler.
Through innovative approaches, we are beginning to understand the lives of these mysterious giants. As is true for many things, the more we learn, the more questions we have. Through the GEMM Lab’s blue whale project, we have determined that a unique population of blue whales occupies the South Taranaki Bight region of New Zealand year-round; they do not simply migrate through as their current threat classification status indicates [10]. But what are their distribution patterns? Can we predict when and where whales are most likely to be in the South Taranaki Bight? Does this population have a different foraging strategy than their Californian, Chilean, or Antarctic counterparts? These are the things we are working on unraveling, and that will aid in their conservation. In the meantime, I’ll keep musing about what we don’t know, and remember to keep marveling at what we do know about the largest creatures on earth.
A blue whale mother and calf surface near Farewell Spit, New Zealand. Photo by D. Barlow.
References:
Clapham, P. J., Young, S. B. & Brownell Jr., R. L. Baleen whales: conservation issues and the status of the most endangered populations. Mamm. Rev.29, 37–60 (1999).
Branch, T. a, Matsuoka, K. & Miyashita, T. Evidence for increases in Antarctic blue whales based on baysian modelling. Mar. Mammal Sci.20, 726–754 (2004).
Branch, T. A. et al. Past and present distribution, densities and movements of blue whales Balaenoptera musculus in the Southern Hemisphere and northern Indian Ocean. Mammal Review37, 116–175 (2007).
George, J. C. et al. Age and growth estimates of bowhead whales (Balaena mysticetus) via aspartic acid racemization. Can. J. Zool.77, 571–580 (1998).
Sears, R. et al. Photographic identification of the Blue Whale (Balaenoptera musculus) in the Gulf of St. Lawrence, Canada. Report of the International Whaling Commission Special Issue 335–342 (1990).
Kenney, R. D., Hyman, M. A. M., Owen, R. E., Scott, G. P. & Winn, H. E. Estimation of prey densities required by Western North Atlantic right whales. Mar. Mammal Sci.2, 1–13 (1986).
Acevedo-Gutierrez, A., Croll, D. A. & Tershy, B. R. High feeding costs limit dive time in the largest whales. J. Exp. Biol.205, 1747–1753 (2002).
Johnson, M. P. & Tyack, P. L. A digital acoustic recording tag for measuring the response of wild marine mammals to sound. IEEE J. Ocean. Eng.28, 3–12 (2003).
Hazen, E. L., Friedlaender, A. S. & Goldbogen, J. A. Blue whales (Balaenoptera musculus) optimize foraging efficiency by balancing oxygen use and energy gain as a function of prey density. Sci. Adv.1, e1500469–e1500469 (2015).
Baker, C. S. et al.Conservation status of New Zealand marine mammals, 2013. (2016).
By Dawn Barlow, MSc Student, Department of Fisheries and Wildlife
The days are growing shorter, and 2017 is drawing to a close. What a full year it has been for the GEMM Lab! Here is a recap, filled with photos, links to previous blogs, and personal highlights, best enjoyed over a cup of hot cocoa. Happy Holidays from all of us!
The New Zealand blue whale team in action aboard the R/V Star Keys. Photo by L. Torres.
Things started off with a bang in January as the New Zealand blue whale team headed to the other side of the world for another field season. Leigh, Todd and I joined forces with collaborators from Cornell University and the New Zealand Department of Conservation aboard the R/V Star Keys for the duration of the survey. What a fruitful season it was! We recorded sightings of 68 blue whales, collected biopsy and fecal samples, as well as prey and oceanographic data. The highlight came on our very last day when we were able to capture a blue whale surface lunge feeding on krill from an aerial perspective via the drone. This footage received considerable attention around the world, and now has over 3 million views!
A blue whale surfaces just off the bow of R/V Star Keys. Photo by D. Barlow.
In the spring Rachael made her way to the remote Pribilof Islands of Alaska to study the foraging ecology of red-legged kittiwakes. Her objectives included comparing the birds that reproduce successfully and those that don’t, however she was thrown a major curveball: none of the birds in the colony were able to successfully reproduce. In fact, they didn’t even build nests. Further analyses may elucidate some of the reasons for the reproductive failure of this sentinel species of the Bering Sea… stay tuned.
Rachael releases a kittiwake on St. George Island. Photo by A. Fleishman.
The 2017 Port Orford field team. Photo by A. Kownacki.
Florence is a newly-minted MSc! In June, Florence successfully defended her Masters research on gray whale foraging and the impacts of vessel disturbance. She gracefully answered questions from the room packed with people, and we all couldn’t have been prouder to say “that’s my labmate!” during the post-defense celebrations. But she couldn’t leave us just yet! Florence stayed on for another season of field work on the gray whale foraging ecology project in Port Orford, this time mentoring local high school students as part of the project. Florence’s M.Sc. defense!
Upon the gray whales’ return to the Oregon Coast for the summer, Leila, Leigh, and Todd launched right back into the stress physiology and noise project. This year, the work included prey sampling and fixed hydrophones that recorded the soundscape throughout the season. The use of drones continues to offer a unique perspective and insight into whale behavior.
Video captured under NOAA/NMFS permit #16111.
Solene with a humpback whale biopsy sample. Photo by N. Job.
Solene spent the austral winter looking for humpback whales in the Coral Sea, as she participated in several research cruises to remote seamounts and reefs around New Caledonia. This field season was full of new experiences (using moored hydrophones on Antigonia seamount, recording dive depths with SPLASH10 satellite tags) and surprises. For the first time, whales were tracked all the way from New Caledonia to the east coast of Australian. As her PhD draws to a close in the coming year, she will seek to understand the movement patterns and habitat preferences of humpback whales in the region.
A humpback whale observed during the 2017 coral sea research cruise. Photo by S. Derville.
During the austral wintertime when most of us were all in Oregon, the New Zealand blue whale project received more and more political and media attention. Leigh was called to testify in court as part of a contentious permit application case for a seabed mine in the South Taranaki Bight. As austral winter turned to austral spring, a shift in the New Zealand government led to an initiative to designate a marine mammal sanctuary in the South Taranaki Bight, and awareness has risen about the potential impacts of seismic exploration for oil and gas reserves. These tangible applications of our research to management decisions is very gratifying and empowers us to continue our efforts.
In the fall, many of us traveled to Halifax, Nova Scotia to present our latest and greatest findings at the 22nd Biennial Conference on the Biology of Marine Mammals. The strength of the lab shone through at the meeting during each presentation, and we all beamed with pride when we said our affiliation was with the GEMM Lab at OSU. In other conference news, Rachael was awarded the runner-up for her presentation at the World Seabird Twitter Conference!
GEMM Lab members present their research. From left to right, top to bottom: Amanda Holdman, Leila Lemos, Solène Derville, Dawn Barlow, Sharon Nieukirk, and Florence Sullivan.
Leigh had a big year in many ways. Along with numerous scientific accomplishments—new publications, new students, successful fieldwork, successful defenses—she had a tremendous personal accomplishment as well. In the spring she was diagnosed with breast cancer, and after a hard fight she was pronounced cancer-free this November. We are all astounded with how gracefully and fearlessly she navigated these times. Look out world, this lab’s Principle Investigator can accomplish anything!
This austral summer we will not be making our way south to join the blue whales. However, we are keenly watching from afar as a seismic survey utilizing the largest seismic survey vessel in the world has launched in the South Taranaki Bight. This survey has been met with considerable resistance, culminating in a rally led by Greenpeace that featured a giant inflatable blue whale in front of Parliament in Wellington. We are eagerly planning our return to continue this study, but that will hopefully be the subject of a future blog.
In our final lab meeting of the year, we went around the table to share what we’ve learned this year. The responses ranged from really grasping the mechanisms of upwelling in the California Current to gaining proficiency in coding and computing, to the importance of having a supportive community in graduate school to trust that the right thing will happen. If you are reading this, thank you for your interest in our work. We are looking forward to a successful 2018. Happy holidays from the GEMM Lab!
GEMM Lab members, friends, and families gather for a holiday celebration.
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!
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:
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.
National Research Council (NRC), Ocean Noise and Marine Mammals. 2003, National Academy Press: Washington. p. 204.
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.
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. .
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.
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.
Di lorio, L. and C.W. Clark, Exposure to seismic survey alters blue whale acoustic communication. Biology Letters, 2010. 6(1): p. 51-54.
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.
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.
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.
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.
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.
By Dawn Barlow, MSc Student, Department of Fisheries and Wildlife, Geospatial Ecology of Marine Megafauna Lab
Every two years, an international community of scientists gather for one week to discuss the most current and pressing science and conservation issues surrounding marine mammals. The thousands of attendees range from longtime researchers who have truly shaped the field throughout the course of their careers to students who are just beginning to carve out a niche of their own. I was able to attend the last conference, which took place in San Francisco in 2015, as an undergraduate. The experience cemented my desire to pursue marine mammal research in graduate school and beyond, and also solidified my connection with Leigh Torres and the Geospatial Ecology of Marine Megafauna Laboratory, leading to my current enrollment at Oregon State University. This year, the 22nd Biennial Conference on the Biology of Marine Mammals takes place in Halifax, Nova Scotia, Canada. At the end of this week, Florence, Leila, Amanda, Solene, Sharon and I will head northeast to represent the GEMM Lab at the meeting!
As those of you reading this may not be able to attend, I’d like to share an overview of what we will be presenting next week. If you will be in Halifax, we warmly invite you to the following presentations. In order of appearance:
Amanda will present the final results from part of her MSc thesis on Monday in a presentation titled Comparative fine-scale harbor porpoise habitat models developed using remotely sensed and in situ data. It will be great for current GEMM Lab members to catch up with this recent GEMM Lab graduate on the other side of the continent! (Session: Conservation; Time: 4:00 pm)
On Tuesday morning, Leila will share the latest and greatest updates on her research about Oregon gray whales, including photogrammetry from drone images and stress hormones extracted from fecal samples! Her presentation is titled Combining traditional and novel techniques to link body condition and hormone variability in gray whales. This is innovative and cutting-edge work, and it is exciting to think it will be shared with the international research community. (Session: Health; Time: 10:45 am)
Did you think humpback whales have been so well studied that we must know just about everything about them? Think again! Solene will be sharing new and exciting insights from humpback whales tagged in New Caledonia, who appear to spend an intriguing amount of time around seamounts. Her talk Why do humpback whales aggregate around seamounts in South Pacific tropical waters? New insights from diving behaviour and ocean circulation analyses, will take place on Tuesday afternoon. (Session: Habitat and Distribution Speed Talks; Time: 1:30 pm)
I will be presenting the latest findings from our New Zealand blue whale research. Based on multiple data streams, we now have evidence for a unique blue whale population which is present year-round in New Zealand waters! This presentation, titled From migrant to resident: Multiple data streams point toward a resident New Zealand population of blue whales, will round out the oral presentations on Tuesday afternoon. (Session: Population Biology and Abundance; Time: 4:45 pm)
The GEMM Lab is using new technologies and innovative quantitative approaches to measure gray whale body condition and behaviors from an aerial perspective. On Wednesday afternoon, Sharon will present Drone up! Quantifying whale behavior and body condition from a new perspective on behalf of Leigh. With the emerging prevalence of drones, we are excited to introduce these quantitative applications. (Session: New Technology; Time: 11:45 am)
GoPros, kayaks, and gray whales, oh my! A limited budget couldn’t stop Florence from conducting excellent science and gaining new insights into gray whale fine-scale foraging. On Thursday afternoon, she will present Go-Pros, kayaks and gray whales: Linking fine-scale whale behavior with prey distributions on a shoestring budget, and share her findings, which she was able to pull off with minimal funds, creative study design, and a positive attitude. (Session: Foraging Ecology Speed Talks; Time: 1:55 pm)
Additional Oregon State University students presenting at the conference will include Michelle Fournet, Samara Haver, Niki Diogou, and Angie Sremba. We are thrilled to have such good representation at a meeting of this caliber! As you may know, we are all working on building the GEMM Lab’s social media presence and becoming more “twitterific”. So during the conference, please be sure to follow @GEMMLabOSU on twitter for live updates. Stay tuned!
A couple weeks ago the GEMM Lab trialed something new in our gray whale research: the addition of a thermal imaging camera to our drone.
For those who do not know what a thermal imaging camera is, it is a device that uses infrared radiation to form an object, and operates in wavelengths as long as 14,000 nm (14 µm). A thermal camera uses a similar procedure as a normal camera, but responds to infrared radiation rather than visible light. It is also known as an infrared or thermographic camera.
All objects with a temperature above absolute zero emit infrared radiation, and thermography makes it possible to see with or without visible light. The amount of radiation emitted by an object intensifies with temperature, thus thermography allows for perception of temperature variations. Humans and other warm-blooded animals are easily detectable via infrared radiation, during the day or the night.
Infrared radiation was first discovered in 1800, by the astronomer Frederick William Herschel. He discovered infrared light by using a prism and a thermometer (Fig.1). He called it the infrared spectrum “dark heat”, which falls between the visible and microwave bands on the electromagnetic spectrum (Hitch 2016).
Figure 1: Astronomer Frederick William Herschel discovers infrared light by using a prism and a thermometer. Source: NASA, 2012.
Around 30 years later it was possible to detect a person using infrared radiation within ten meters distance, and around 50 years later it was possible to detect radiation from a cow at 400 meters distance, as technology became gradually more sensitive (Langley, 1880).
Thermography nowadays is applied in research and development in a variety of different fields in industry (Vollmer and Möllmann 2017). Thermal imaging is currently applied in many applications, such as night vision, predictive maintenance, reducing energy costs of processes and buildings, building and roof inspection, moisture detection in walls and roofs, energy auditing, refrigerant leaks and detection of gas, law enforcement and anti-terrorism, medicinal and veterinary thermal imaging, astronomy, chemical imaging, pollution effluent detection, archaeology, paranormal investigation, and meteorology.
Some of the most interesting examples of its application are:
Detection of the presence of icebergs, increasing safety for navigators.
Detection of bombs
Non-invasive detection of breast cancer (Fig.2)
Detection of fire, and detection of fire victims in smoke-filled rooms or hidden under plywood, by the fire departments (Fig.3)
Figure 2: Thermography approved in 1982 to detect breast cancer. Method is able to detect 95% of early stages cancers. Source: Hitch, 2016.
Figure 3: The use of thermal imaging cameras by the fire departments. Source: MASC, 2017.
In environmental research, the thermal imaging camera is an interesting tool used to detect wildlife presence (especially for nocturnal species), to monitor wildlife and detect disease (Fig.4), and to better understand thermal patterns in animals (Fig.5), among others.
Figure 4: Wildlife monitoring: detection of mange infection in wolves of Yellowstone National Park. During winter, wolves infected with mange can suffer a substantial amount of heat loss compared to those without the disease, according to a study by the U.S. Geological Survey and its partners. Source: Wildlife Research News 2012; USGS 2016.
Figure 5: Study on thermal patterns and thermoregulation abilities of emperor penguins in Antarctica. Source: BBC 2013.
Now that thermal cameras are small enough for attachment to drones, we are eager to monitor whales with this device to potentially identify injuries and infections. This non-invasive method could contribute another aspect to our on-going blue and gray whale health assessment work. However, dealing with new technology is never easy and we are working to optimize settings to collect the data needed. Our test flights with the thermal camera were successful – we captured images and retrieved the expensive camera (always a good thing!) – but the whale images were less clear than desired. The camera was able to detect thermal variation between our research vessel and the ocean (Fig. 6: boat and people are displayed as hot coloration (yellow, orange and red tones), while the ocean exhibited a cold coloration (purple). Yet, the camera’s ability to differentiate thermal content of the whale while surfacing from the ocean was less evident (Fig. 7). We believe this problem is due to automatic gain control settings by the camera that essentially continually shifts the baseline temperature in the image so that thermal contrast between the whale and ocean was not very strong, except for those hot blow holes shinning like devil eyes (Fig. 7). We are working to adjust these gain settings so that our next trial will be more successful, and next time we will see our whales in all their colorful thermal glory.
Figure 6: Thermal image of the R/V Ruby captured by a thermal camera flown on a drone by the GEMM Lab on September 09th, 2017. Source: GEMMLab 2017.Figure 7. Thermal image of a gray whale captured by a thermal camera flown on a drone by the GEMM Lab on September 09th, 2017. Notice the ‘hot’ color (yellow-orange) of the blow holes indicating the heat within the whale’s body. (Image captured under NOAA/NMFS permit #16111).
References
BBC. 2013. In pictures: Emperor penguins’ ‘cold coat’ discovered. Available at: http://www.bbc.co.uk/nature/21669963
Hitch J. 2016. A Brief History of Thermal Cameras. Available at: http://www.newequipment.com/technology-innovations/brief-history-thermal-cameras /gallery?slide=1
Langley SP. 1880. The bolometer. Vallegheny Observatory, The Society Gregory, New York, NY, USA.
NASA. 2012. Beyond the Visible Light. Available at: https://www.nasa.gov/topics/ technology/features/webb-beyond-vis.html
USGS. 2016. Study Shows Cold and Windy Nights Physically Drain Mangy Wolves. Available at: https://www.usgs.gov/news/study-shows-cold-and-windy-nights-physically-drain-mangy-wolves
Vollmer M. and Möllmann KP. 2018. Infrared Thermal Imaging: Fundamentals, research and Applications. Second Edition. Wiley-VCH: Weinheim, Germany.
Wildlife Research News, 2012. Tool: Infrared Monitoring. Available at: https://wildliferesearchnews.wordpress.com/2012/04/24/tool-infrared-monitoring/
By Dawn Barlow, MSc Student, Department of Fisheries and Wildlife, Geospatial Ecology of Marine Megafauna Lab
In late February, we wrapped up our 2017 blue whale survey of the South Taranaki Bight region. Upon returning to port in Wellington, Leigh and I each located our one remaining clean shirt, drank a cup of coffee, and walked into a room full of lawyers in suits where Leigh testified in front of the Environmental Protection Authority’s (EPA) Decision Making Committee. The hearing was for Trans-Tasman Resources, Ltd. (TTR)’s application for a permit to extract 50 million tons of iron sands per year from the sea floor for a 35-year period. Our reason for being there? Leigh was called as an expert witness to present our findings on blue whale distribution and ecology in the region where the proposed mining operation will be so that the potential impacts could be properly evaluated by the Decision Making Committee. Talk about seeing an immediate application of your research!
A pair of blue whales observed in February 2017 in the South Taranaki Bight.
Fast forward several months. The decision of whether or not the permit will be granted has been delayed, more evidence has been requested and considered, Leigh has testified again via skype, and the decision has been delayed yet again. It is a contentious case, and people on both sides have grown impatient, concerned, and frustrated. Finally, the date and time of the decision announcement finds me nervously refreshing my browser window until I see the outcome: the mining permit has been approved. It was a split decision by the committee of four, with the committee chair casting the deciding vote.
A schematic of the operations of the proposed seabed mine in the South Taranaki Bight. Source: Kiwis Against Seabed Mining (kasm.org.nz).
While the Decision Making Committee was split on whether or not the permit should be approved, the constituency was not. During the hearing process, over 13,700 submissions were received, 99% of which were in opposition to the mining operation. Opposition came from Iwi (Maori tribes), commercial and recreational fishing industries, scientists, and residents of local coastal communities.
What does this mean for New Zealand, for the whales, for the ecosystem, for the future? This decision represents a landmark case that will surely set a new precedent. It is the first of its kind to be approved in New Zealand, and the first commercial scale seabed mining operation in the world. Other permit applications for seabed mines elsewhere will no doubt be submitted in the wake of the approval of TTR’s iron sands mining operation. The groups Kiwis Against Seabed Mining and Greenpeace New Zealand have announced that they will appeal the EPA’s decision in High Court, and TTR cannot begin dredging until all appeals are heard and two years of environmental monitoring have taken place.
So for the time being, life continues as usual for the blue whales. They will carry on feeding and raising their young in the South Taranaki Bight, where they already are surrounded by oil rigs, vessel traffic, and seismic airguns. In the meantime, above the water’s surface, many dedicated individuals are prepared to fight hard for environmental conservation. The blue whales will likely continue to unknowingly play a role in the decision-making process as our data demonstrate the importance of this region to their ecology, and the New Zealand public and media continue to learn about these iconic animals. The research effort I am part of has the potential to immediately and concretely influence policy decisions, and I sincerely hope that our findings will not fall on deaf ears in the appeal process. While we continue to provide biological evidence, politicians, the media, and the public need to emphasize the value of preserving biodiversity. These blue whales can be a figurehead for a more sustainable future for the region.
If you are interested in learning more, I invite you to take a minute to visit the web pages listed below.
Kiwis against seabed mining (KASM), the group leading the effort to stop seabed mining in New Zealand: http://kasm.org.nz/
My name is Taylor Mock. Since February I have been volunteering in the GEMM Lab and am ecstatic to make my online debut as part of the team!
For many years, I had a shallow relationship with Hatfield Marine Science Center. As a Newport native, I would spend mornings and evenings glancing over at the Hatfield buildings while driving over the bridge to and from school. I was always intrigued. Sure, I would hear snippets of research from my peers about what projects their parents were involved in, but the inner workings of the complex mystified me.
Toward the end of my Freshman year in 2012 at Westmont College in Santa Barbara, California, my mom asked me what my summer plans were. I replied with the typical “I don’t know… Get a job?” She insisted that instead of a job I think about getting an internship; experience that will last more than a summer. I inquired through a family friend (because every person in this little community is woven together some way or another) if any internships or volunteer opportunities were available at Hatfield. She pointed me in the direction of the Environmental Protection Agency and thus began my Hatfield volunteering saga. I worked that summer, and the next, at the EPA under the direction of Ted DeWitt and Jody Stecher on denitrification studies in estuarine marshes. That summer provided me a glorious front row seat to field research and a greater understanding of my potential as a person and as a scientist. Now, this experience was marvelous, but I knew shortly after starting that my heart was elsewhere.
It was during my study abroad semester in Belize as part of my internship at the Toledo Institute for Development and Environment (TIDE) that I realized I wanted to work with marine macroorganisms. At TIDE, I engaged in radio telemetry conservation efforts tracking Hicatee (Dermatemys mawii) aquatic turtles. We would spend days on a small boat floating through canals and setting nets in hopes of capturing individuals of this small population to outfit them with radio tracking devices. These would be later used to track foraging, mating, and travel patterns in the region. It was an amazing time, to say the least. I remember waking up on my 21st birthday from my camping hammock and staring up at the lush rainforest above my head with a warm breeze across my face, followed by spending the day in the presence of these glorious creatures. It was heaven. I returned to Westmont the following term and took a Marine Mammal Eco-Physiology course and absolutely fell in love with Cetacea. Yes, I had always been captivated by this clade of beings (and truthfully when I was eight years old had a book on “How to Become a Marine Mammal Trainer”), but this was deeper. Of course, pinnipeds and otters and polar bears and manatees were enjoyable to learn about. There was something about the Cetacea though and how they migrated up and down the coast (just like me!) that I really connected with. My time learning about these animals created an intimate understanding of another group of species that developed into a rich, indescribable empathetic connection. I had to take a couple years away from scholastics and away from biology for health and wellness reasons. One day, though, a couple years after graduating and returning to Newport I rekindled with Jody from the EPA. He asked me if I would like to volunteer under Leigh Torres in the Marine Mammal Institute at HMSC. I do not think I could have possibly said no. I have been enjoying my time in the GEMM Lab ever since!
Though I am available to help anyone with any task they need, the work I do mostly centers around photogrammetry.
Using photogrammetry skills to measure gray whales in the GEMM Lab.
Photogrammetry, essentially, means geo-spatially measuring objects using photographs. What that looks like for me is taking an aerial photograph (extracted from overhead drone video footage) of a whale, running the image through a computer program called “Matlab”, taking a series of measurements from the whale (e.g., tip of the mandible to the notch of the fluke, distance between each tip of the fluke, and several measurements across the midsection of the whale). Several images of individuals are processed in order to find an average set of measurements for each whale.
Final result of the photogrammetry method on a gray whale
You might be wondering, “How can one measure the distance accurately from just a photograph?” I am glad you asked! The drones are outfitted with a barometer to measure the atmospheric pressure and, in turn, altitude. The changing altitudes are recorded in a separate program that is run simultaneously with the video footage. Thus, we have the altitudinal measurements for every millisecond of the drone’s flight. To monitor the accuracy and functionality of the barometer, calibrations are completed upon deployment and retrieval of each drone flight. To calibrate: the initial takeoff height is measured, a board of known length is thrown into the water, the drone will then rise or lower slowly above the board between 10 and 40 m, photographs of the board are then taken from varying altitudes, and are processed in Matlab.
During my time in the GEMM Lab, I have had the pleasure of completing photogrammetry assignments for both Leila on the Oregon Coast gray whale and for Dawn on the New Zealand blue whale projects. These ladies, and the other members of the GEMM Lab, have been so patient and gracious in educating me on the workings of Matlab and the video processing systems. It is a distinct honor working with them and to delight in the astounding nature of these creatures together. Each day I am struck in sheer awe of how beautiful and powerful these whales truly are. Their graceful presence and movement through the water rivals even the most skillful dancer.
Over the last 6 years, I am delighted to say that my relationship with Hatfield has become much deeper. The people and the experiences I have encountered during my time here, especially in the GEMM Lab, have been nothing short of incredible. I am sincerely grateful for this continued opportunity. It fills my soul with joy to engage in work that contributes to the well being of the ocean and its inhabitants.
Thank you, Leigh and all of the GEMM Lab members. I hope to continue volunteering with you for as long as you will have me.
By Dawn Barlow, MSc student, OSU Department of Fisheries and Wildlife, Geospatial Ecology of Marine Megafauna Lab
I was fortunate enough to spend the Austral summer in the field, and so while the winter rain poured down on Oregon I found myself on the water with the sun and wind on my face, looking for blue whales in New Zealand. This spring I switched gears and spent time taking courses to build my analytical toolbox. In a course on technical writing and communication, I was challenged to present my research using only pictures and words with no written text, and to succinctly summarize the importance of my research in an introduction to a technical paper. I attended weekly seminars to learn about the diverse array of marine science being conducted at Oregon State University and beyond. I also took a course entitled “Advanced Spatial Statistics and Geographic Information Science”. In this skill-building course, we were given the opportunity to work with our own data. Even though my primary objective was to expand the tools in my toolbox, I was excited to explore preliminary results and possible insight into blue whale habitat selection in my study area, the South Taranaki Bight region (STB) of New Zealand (Figure 1).
Figure 1. A map of New Zealand, with the South Taranaki Bight (STB) region delineated by the black box. Farewell Spit is denoted by a star, and Kahurangi point is denoted by an X.
Despite the recent documentation of a foraging ground in the STB, blue whale distribution remains poorly understood in New Zealand. The STB is New Zealand’s most industrially active marine region, and the site of active oil and gas extraction and exploration, busy shipping traffic, and proposed seabed mining. This potential space-use conflict between endangered whales and industry warrants further investigation into the spatial and temporal extent of blue whale habitat in the region. One of my research objectives is to investigate the relationship between blue whales and their environment, and ultimately to build a model that can predict blue whale presence based on physical and biological oceanographic features. For this spring term, the question I asked was:
Is the number of blue whales present in an area correlated with remotely-sensed sea surface temperature and chlorophyll-a concentration?
For the purposes of this exploration, I used data from our 2017 survey of the STB. This meant importing our ship’s track and our blue whale sighting locations into ArcGIS, so that the data went from looking like this:
… to this:
The next step was to get remote-sensed images for sea surface temperature (SST) and chlorophyll-a (chl-a) concentration. I downloaded monthly averages from the NASA Moderate Resolution Imaging Spectrometer (MODIS aqua) website for the month of February 2017 at 4 km2 resolution, when our survey took place. Now, my images looked something more like this:
But, I can’t say anything reliable about the relationships between blue whales and their environment in the places we did not survey. So next I extracted just the portions of my remote-sensed images where we conducted survey effort. Now my maps looked more like this one:
The above map shows SST along our ship’s track, and the locations where we found whales. Just looking at this plot, it seems like the blue whales were observed in both warmer and colder waters, not exclusively in one or the other. There is a productive plume of cold, upwelled water in the STB that is generated off of Kahurangi point and curves around Farewell Spit and into the bight (Figure 1). Most of the whales we saw appear to be near that plume. But how can I find the edges of this upwelled plume? Well, I can look at the amount of change in SST and chl-a across a spatial area. The places where warm and cold water meet can be found by assessing the amount of variability—the standard deviation—in the temperature of the water. In ArcGIS, I calculated the deviation in SST and chl-a concentration across the surrounding 20 km2 for each 4 km2 cell.
Now, how do I tie all of these qualitative visual assessments together to produce a quantitative result? With a statistical model! This next step gives me the opportunity to flex some other analytical muscles, and practice using another computational tool: R. I used a generalized additive model (GAM) to investigate the relationships between the number of blue whales observed in each 4 km2 cell our ship surveyed and the remote-sensed variables. The model can be written like this:
Number of blue whales ~ SST + chl-a + sd(SST) + sd(chl-a)
In other words, are SST, chl-a concentration, deviation in SST, and deviation in chl-a concentration correlated with the number of blue whales observed within each 4 km2 cell on my map?
This model found that the most important predictor was the deviation in SST. In other words, these New Zealand blue whales may be seeking the edges of the upwelling plume, honing in on places where warm and cold water meet. Thinking back on the time I spent in the field, we often saw feeding blue whales diving along lines of mixing water masses where the water column was filled with aggregations of krill, blue whale prey. Studies of marine mammals in other parts of the world have also found that eddies and oceanic fronts—edges between warm and cold water masses—are important habitat features where productivity is increased due to mixing of water masses. The same may be true for these New Zealand blue whales.
These preliminary findings emphasize the benefit of having both presence andabsence data. The analysis I have presented here is certainly strengthened by having environmental measurements for locations where we did not see whales. This is comforting, considering the feelings of impatience generated by days on the water spent like this with no whales to be seen:
Moving forward, I will include the blue whale sighting data from our 2014 and 2016 surveys as well. As I think about what would make this model more robust, it would be interesting to see if the patterns become clearer when I incorporate behavior into the model—if I look at whales that are foraging and traveling separately, are the results different? I hope to explore the importance of the upwelling plume in more detail—does the distance from the edge of the upwelling plume matter? And finally, I want to adjust the spatial and temporal scales of my analysis—do patterns shift or become clearer if I don’t use monthly averages, or if I change the grid cell sizes on my maps?
I feel more confident in my growing toolbox, and look forward to improving this model in the coming months! Stay tuned.
