If you are an avid reader of our blog, you probably know quite a bit about gray whales, specifically the Pacific Coast Feeding Group (PCFG) of gray whales. Of the just over 50 GEMM Lab blogs written in 2021, 43% of them were about PCFG gray whales (or at least mentioned gray whales in some way). I guess this statistic is not too surprising when you consider that six of the 10 GEMM Lab members conduct gray whale-related research. You might think that we would have reached our annual limit of online gray whale content with that many blogs featuring these gentle giants, but you would in fact be wrong…
At the end of 2021, we launched a brand new website all about gray whales called IndividuWhale! It features stories of some of the Oregon coast’s most iconic gray whales, as well as information about how we study them, stressors they experience in our waters, and even a game to test your gray whale identification skills. IndividuWhale is a true labor of love that took over a year to create and that we are extremely proud to share with you today. Before I tell you more about the website, I want to take a moment to give a huge shout out to Erik Urdahl who was instrumental in getting this website off the ground and making it as interactive and beautiful as it is – hurrah Erik!
Equal‘s right side with visible boat propeller scars. Source: GEMM Lab.
Like us humans, gray whales have individual personalities and stories. They experience life-altering events, go through periods of stress, must provide for their offspring, and can behave differently to one another. Since Leigh & co. have been conducting in-depth research about PCFG gray whales in Oregon waters since 2016, we have been able to document several fascinating stories and events that these individuals have experienced. Take Equal, for example, a male whale that is at least 7 years old. The GEMM Lab observed Equal on consecutive days in June 2018, where on the first day he looked healthy and normal, but on the second day had fresh boat propeller-like scars on his back. Not only did we document these scars in photographs, but we were also able to collect a fecal sample from Equal the day we observed him with these scars. After analyzing his fecal sample for stress hormones, we discovered that Equal had very high stress levels compared to previous samples collected – unsurprising seeing as he had been hit by a boat! While this event was certainly sad for Equal (although don’t worry – we have seen him many times again in the years after this event looking healthy & normal once again), it was a very fortuitous occurrence for us since we were able to “validate” our stress hormone data relative to the value from Equal when he was clearly stressed out. Find out more about Equal as well as seven other gray whales here!
You might be wondering, how we knew that the whale with the boat propeller scar was Equal and how we recognize him again years after the incident. Gray whales have unique pigmentation patterns on their bodies and flukes that allow us to re-identify individuals between years and distinguish them from one another. Additionally, scars, such as those that Equal now carries on his back, can also be useful in telling whales apart. Therefore, we take photographs of every whale we see to match markings and identify whales. This process is called photo ID. Some individuals can have very distinctive markings, such as Roller Skate who has two big white dots on her right side, while others can look more inconspicuous, like Clouds. Therefore, conducting photo ID requires a lot of attention to detail and perseverance. To learn more about the different features we use to identify individuals, check out the “Studying Whales With Photographs” page. Do you think you have what it takes to tell individuals apart? Then try your luck at our photo ID game after!
Test your photo ID skills in our whale match game!
Unfortunately, these whales do not live in a pristine environment, as is evidenced by Equal’s story. Their main objective during the summer when in Oregon waters is to gain weight (energy stores) by consuming large amounts of prey, which is made more difficult by a number of stressors, including potential fishery entanglements, ocean noise, vessel traffic, and habitat changes. We describe these four stressors on the IndividuWhale website since we are trying to assess the impacts of them on gray whales through our research, however they are certainly not the only stressors that these whales experience. Little is known about the level at which these stressors may have a negative impact on the whales, and how whales react when they experience some of these stressors in concert. The answers to these questions are difficult to tease apart but the GRANITE project is aiming to do so through a framework called Population Consequences of Multiple Stressors (read more about it here). This approach requires a lot of data on a lot of individuals in a population and as you can see from the IndividuWhale website, we are slowly starting to get there! 2022 will certainly bring many more gray whale-themed blogs to this website, and you can share in our journey of learning about the lives of PCFG gray whales by exploring the IndividuWhale website (https://www.individuwhale.com).
Dr. KC Bierlich, Postdoctoral Scholar, OSU Department of Fisheries, Wildlife, & Conservation Sciences, Geospatial Ecology of Marine Megafauna (GEMM) Lab
The recent advancement in drones (or unoccupied aircraft systems, UAS) has greatly enhanced opportunities for scientists across a broad range of disciplines to collect high-resolution aerial imagery. Wildlife researchers in particular have utilized this technology to study large elusive animals, such as whales, to observe their behavior (see Clara Bird’s blog) and obtain morphological measurements via photogrammetry (see previous blog for a brief history on photogrammetry and drones). However, obtaining useful measurement data is not as easy as flying the drone and pressing record. For this blog, I will provide a brief overview on the basics of using photogrammetry to extract morphological measurements from images collected with drones, as well as the associated uncertainty from using different drone platforms.
During my PhD at Duke University, I co-developed an open-source photogrammetry software called MorphoMetriX to measure whales in images I collected using drones (Fig. 1) (Torres and Bierlich, 2020) (see this blog for some fieldwork memoirs!). The software is designed to be flexible, simple to use, and customizable without knowledge of scripting languages. Using MorphoMetriX, measurements are made in pixels and then multiplied by the ground sampling distance (GSD) to convert to standard units (e.g., meters) (Fig. 2A). GSD represents the distance on the ground each pixel represents (i.e., the linear size of the pixel) and therefore sets the scale of the image (i.e., cm per pixel). Figure 2A describes how GSD is dependent on the camera sensor, focal length lens, and altitude. Thus, drones equipped with different cameras and focal length lenses will have inherent differences in GSD as altitude increases (Fig. 2B). A larger GSD increases the length each pixel represents in a photo and results in a lower resolution image, potentially obscuring important features in the photo and introducing measurement error.
Figure 1. An example of a Pacific Coast Feeding Group gray whale measured in MorphoMetriX (Torres & Bierlich, 2020).Figure 2: Overview of photogrammetry methods and calculating ground sampling distance (GSD). A) Photogrammetry methods for how each image is scaled to convert measurements in pixels to standard units (e.g., meters). Altitude is the distance between the camera lens and whale (usually at the surface of the water). Figure from Torres and Bierlich (2020). B) The exact (not accounting for distortion or altitude error) ground sampling distance (GSD) for two drone platforms commonly used to obtain morphological measurements of cetaceans. The difference in GSD between the P4Pro and Inspire 1 is due to the difference in sensor width and focal lengths of the cameras used. Figure from Bierlich et al. (2021).
Obtaining accurate altitude information is a key component in obtaining accurate measurements. All drones are equipped with a barometer, which measures altitude from changes in pressure. In general, barometers usually yield low accuracy in the altitude recorded, particularly for low-cost sensors commonly found on small, off-the-shelf drones (Wei et al., 2016). Dawson et al. (2017) added a laser altimeter (i.e., LightWare SF11/C, https://www.mouser.com//datasheet//2//321//28054-SF11-Laser-Altimeter-Manual-Rev8-1371857.pdf) to a drone, which yields higher accuracy in the altitude recorded. Since then, several studies have adopted use of a laser altimeter to study different species of baleen whales (i.e., Gough et al., 2019; Christiansen et al., 2018).
The first chapter of my dissertation, which was published last year in Marine Ecology Progress Series, compared the accuracy of several drones equipped with different camera sensors, focal length lenses, and a barometer vs. laser altimeter (Bierlich et al., 2021). We flew each drone over a known sized object floating at the surface and collected images at various altitudes (between 10 – 120 m). We used the known size of the floating object to determine the percent error of each measurement at each altitude. We found that 1) there is a lot of variation in measurement error across the different drones when using a barometer to measure altitude and 2) using a laser altimeter dramatically reduces measurement error for each drone (Fig. 3).
Figure 3. The % error for measurements from different drones. Black dashed line represents 0% error (true length = 1.48 m). The gray dashed lines represent under- and over-estimation of the true length by 5% (1.41 and 1.55 m, respectively).
These findings are important because if a study is analyzing measurements that are from more than one drone, the uncertainty associated with those measurements must be taken into account to know if measurements are reliable and comparable. For instance, let’s say we are comparing the body length of two different populations and found that population A is significantly longer than population B. From looking at Figure 3, that significant difference in length between population A and B could be unreliable as the difference may be due to the bias introduced by the type of drone, camera sensor, focal length lens, and whether a barometer or laser altimeter was used for recording altitude. In other words, without incorporating uncertainty associated with each measurement, how do you trust your measurement?
Hence, the National Institute of Standards and Technology (NIST) states that a measurement is complete only when accompanied by a quantitative statement of its uncertainty (Taylor & Kuyatt, 1994). In our Bierlich et al. (2021) study, we develop a Bayesian statistical model where we use the measurements of the known-sized object floating at the surface (what was used for Fig. 3) as training data to predict the lengths of unknown-sized whales. This Bayesian approach views data and the underlying parameters that generated the data (such as the mean or standard deviation) as random, and thus can be described by a statistical distribution. Using Bayes’ Theorem, a model of the observed data (called the likelihood function), is combined with prior knowledge pertaining to the underlying parameters (called the prior probability distribution) to form the posterior probability distribution, which serves as updated knowledge about the underlying parameter. For example, if someone told me they saw a 75 ft blue whale, I would not be phased. But if someone told me they saw a 150 ft blue whale, I would be skeptical – I’m using prior knowledge to determine the probability of this statement being true.
The posterior probability distribution produced by this Bayesian approach can also serve as new prior information for subsequent analyses. Following this framework, we used the known-sized objects to first estimate the posterior probability distribution for error for each drone. We then used that posterior probability distribution for error specific to each drone platform as prior information to form a posterior predictive distribution for length of unknown-sized whales. The length of an individual whale can then be described by the mean of this second posterior predictive distribution, and its uncertainty defined as the variance or an interval around the mean (Fig. 4).
Figure 4. An example of a posterior predictive distribution for total length of an individual blue whale. The black bars represent the uncertainty around the mean value (the black dot) – the longer black bars represent the 95% highest posterior density (HPD) interval, and the shorter black bars represent the 65% HPD interval.
For over half a decade, the GEMM Lab has been collecting drone images of Pacific Coast Feeding Group (PCFG) of gray whales off the coast of Oregon to measure their morphology and body condition (see GRANITE Project Blog). We have been using several different types of drones equipped with different cameras, focal length lenses, barometers, and laser altimeters. These measurements from different drones will inherently have different levels of error associated with them, so adapting these methods for incorporating uncertainty will be key to ensure our measurements are comparable and analyses are robust. To do this, we fly over a known-sized board (1 m) at the start of each flight to use as training data to generate a posterior predictive distribution for length of the an unknown-sized PCFG gray whale that we fly over (Fig. 5). Likewise, we are working closely with several other collaborators who are also using different drones. Incorporating measurement uncertainty from drones used across research labs and in different environments will help ensure robust analyses and provide great opportunity for some interesting comparisons – such as differences in gray whale body condition on their feeding grounds in Oregon vs. their breeding grounds in Baja, Mexico, and morphological comparisons with other baleen whale species, such as blue and humpback whales. We are currently wrapping up measurement from thousands of boards (Fig. 5) and whales (Fig. 1) from 2016 – 2021, so stay tuned for the results!
Figure 5. An example of a known-sized object (1 m long board) used as training data to assess measurement uncertainty.
References
Bierlich, K.C., Schick, R.S., Hewitt, J., Dale, J., Goldbogen, J.A., Friedlaender, A.S., Johnston D.J. (2021). A Bayesian approach for predicting photogrammetric uncertainty in morphometric measurements derived from UAS. Marine Ecology Progress Series. DOI: https://doi.org/10.3354/meps13814
Christiansen F, Vivier F, Charlton C, Ward R, Amerson A, Burnell S, Bejder L (2018) Maternal body size and condition determine calf growth rates in southern right whales. Mar Ecol Prog Ser 592: 267−281
Dawson SM, Bowman MH, Leunissen E, Sirguey P (2017) Inexpensive aerial photogrammetry for studies of whales and large marine animals. Front Mar Sci 4: 366
Gough, W.T., Segre, P.S., Bierlich, K.C., Cade, D.E., Potvin, J., Fish, F. E., Dale, J., di Clemente, J., Friedlaender, A.S., Johnston, D.W., Kahane-Rapport, S.R., Kennedy, J., Long, J.H., Oudejans, M., Penry, G., Savoca, M.S., Simon, M., Videsen, S.K.A., Visser, F., Wiley, D.N., Goldbogen, J.A. (2019). Scaling of swimming performance in baleen whales. Journal of Experimental Biology, 222(20).https://doi.org/10.1242/jeb.204172
Taylor, B. N., and Kuyatt, C. E. (1994). Guidelines for Evaluating and Expressing the Uncertainty of NIST Measurement Results. Washington, DC: National Institute of Standards and Technology. 1–25.
Torres, W.I., & Bierlich, K.C. (2020). MorphoMetriX: a photogrammetric measurement GUI for morphometric analysis of megafauna. Journal of Open Source Software, 5(45), 1825. https://doi.org/10.21105/joss.01825
Wei S, Dan G, Chen H (2016) Altitude data fusion utilizing differential measurement and complementary filter. IET Sci Meas Technol (Singap) 10: 874−879
With the GRANITE field season officially over, we are now processing all of the data we collected this summer. For me, I am starting to go through all the drone videos to take snapshots of each whale to measure their body condition. As I go through these videos, I am reflecting on the different experiences I am fortunate enough to have with flying different drones, in different environments, over different species of baleen whales: blue, humpback, Antarctic minke, and now gray whales. Each of these species have a different morphological design and body shape (Woodward et al., 2006), which leads to different behaviors that are noticeable from the drone. Drones create immense opportunity to learn how whales thrive in their natural environments [see previous blog for a quick history], and below are some of my memories from above.
I first learned how drones could be used to study the morphology and behavior of large marine mammals during my master’s degree at Duke University, and was inspired by the early works of John Durban (Durban et al., 2015, 2016) Fredrick Christiansen (Christiansen et al., 2016) and Leigh Torres (Torres et al., 2018). I immediately recognized the value and utility of this technology as a new tool to better monitor the health of marine mammals. This revelation led me to pursue a PhD with the Duke University Marine Robotics and Remote Sensing (MaRRS) Lab led by Dr. Dave Johnston where I helped further develop tools and methods for collecting drone-based imagery on a range of species in different habitats.
When flying drones over whales, there are a lot of moving parts; you’re on a boat that is moving, flying something that is moving, following something that is moving. These moving elements are a lot to think about, so I trained hard, so I did not have to think about each step and flying felt intuitive and natural. I did not grow up playing video games, so reaching this level of comfort with the controls took a lot of practice. I practiced for hours over the course of months before my first field excursion and received some excellent mentorship and training from Julian Dale, the lead engineer in the MaRRS Lab. Working with Julian and the many hours of training helped me establish a solid foundation in my piloting skills and feel confident working in various environments on different species.
Blue whales offshore of Monterey, California.
In 2017 and 2018 I was involved in collaborative project with the MaRRS Lab and Goldbogen Lab at Stanford University, where we tagged and flew drones over blue whales offshore of Monterey, California. We traveled about an hour offshore and reliably found groups of blue whales actively feeding. Working offshore typically brought a large swell, which can often make landing the drone back into your field partner’s hands tricky as everything is bobbing up and down with the oscillations of the swell. Fortunately, we worked from a larger research vessel (~56 ft) and quickly learned that landing the drone in the stern helped dampen the effects of bobbing up and down. The blue whales we encountered often dove to a depth of around 200 m for about 20-minute intervals, then come to the surface for only a few minutes. This short surface period provided only a brief window to locate the whale once it surfaced and quickly fly over it to collect the imagery needed before it repeated its dive cycle. We learned to be patient and get a sense of the animal’s dive cycle before launch in order to time our flights so the drone would be in the air a couple of minutes before the whale surfaced.
Once over the whales, the streamlined body of the blue whales was noticeable, with their small, high aspect ratio flippers and fluke that make them so well adapted for fast swimming in the open ocean (Fig. 1) (Woodward et al., 2006). I also noticed that because these whales are so large (often 21 – 24 m), I often flew at higher altitudes to be able fit them within the field of view of the camera. It was also always shocking to see how small the tagging boat (~8 m) looked when next to Earth’s largest creatures.
Figure 1. Two blue whales surface after a deep dive offshore of Monterey, Ca. (Image credit: Duke University Marine Robotics and Remote Sensing under NOAA permit 14809-03)
Antarctic minke whales and humpback whales along the Western Antarctic PeninsulaA lot of the data included in my dissertation came from work along the Western Antarctic Peninsula (WAP), which had a huge range of weather conditions, from warm and sunny days to cold and snowy/foggy/rainy/windy/icy days. A big focus was often trying to keep my hands warm, as it was often easier to fly without gloves in order to better feel the controls. One of the coldest days I remember was late in the season in mid-June (almost winter!) in Wilhemina Bay where ice completely covered the bay in just a couple hours, pushing the whales out into the Gerlache Strait; I suspect this was the last ice-free day of the season. Surprisingly though, the WAP also brought some of the best conditions I have ever flown in. Humpback and Antarctic minke whales are often found deep within the bays along the peninsula, which provided protection from the wind. So, there were times where it would be blowing 40 mph in the Gerlache Strait, but calm and still in the bays, such as Andvord Bay, which allowed for some incredible conditions for flying. Working from small zodiacs (~7 m) allowed us more maneuverability for navigating around or through the ice deep in the bays (Fig. 2)
Figure 2. Navigating through ice-flows along the Western Antarctic Peninsula. (Image credit: Duke University Marine Robotics and Remote Sensing under NOAA permit 14809-03 and ACA permits 2015-011 and 2020-016.)
Flying over Antarctic minke whale was always rewarding, as they are very sneaky and can quickly disappear under ice flows or in the deep, dark water. Flying over them often felt like a high-speed chase, as their small streamlined bodies makes them incredibly quick and maneuverable, doing barrel rolls, quick banked turns, and swimming under and around ice flows (Fig. 3). There would often be a group between 3-7 individuals and it felt like they were playing tag with each other – or perhaps with me!
Figure 3. Two Antarctic minke whales swimming together along the Western Antarctic Peninsula. (Image credit: Duke University Marine Robotics and Remote Sensing under NOAA permit 14809-03 and ACA permits 2015-011 and 2020-016.)
Humpbacks displayed a wide range of behaviors along the WAP. Early in the season they continuously fed throughout the entire day, often bubble net feeding in groups typically of 2-5 animals (Fig. 4). For as large as they are, it was truly amazing to see how they use their pectoral fins to perform quick accelerations and high-speed maneuvering for tight synchronized turns to form bubble nets, which corral and trap their krill, their main food source (Fig. 4) (Woodward et al., 2006). Later in the season, humpbacks switched to more resting behavior in the day and mostly fed at night, taking advantage of the diel vertical migration of krill. This behavior meant we often found humpbacks snoozing at the surface after a short dive, as if they were in a food coma. They also seemed to be more curious and playful with each other and with us later in the season (Fig. 5).
We also encountered a lot of mom and calf pairs along the WAP. Moms were noticeably skinny compared to their plump calf in the beginning of the season due to the high energetic cost of lactation (Fig. 6). It is important for moms to regain this lost energy throughout the feeding season and begin to wean their calves. I often saw moms refusing to give milk to their nudging calf and instead led teaching lessons for feeding on their own.
Figure 4. Two humpback whales bubble-net feeding early in the feeding season (December) along the Western Antarctic Peninsula. (Image credit: Duke University Marine Robotics and Remote Sensing under NOAA permit 14809-03 and ACA permits 2015-011 and 2020-016.)Figure 5. A curious humpback whale dives behind our Zodiac along the Western Antarctic Peninsula. (Image credit: Duke University Marine Robotics and Remote Sensing under NOAA permit 14809-03 and ACA permits 2015-011 and 2020-016.)Figure 6. A mom and her calf rest at the surface along the Western Antarctic Peninsula. Note how the mom looks skinnier compared to her plump calf, as lactation is the most energetically costly phase of the reproductive cycle. (Image credit: Duke University Marine Robotics and Remote Sensing under NOAA permit 14809-03 and ACA permits 2015-011 and 2020-016.)
Gray whales off Newport, Oregon
All of these past experiences helped me quickly get up to speed and jump into action with the GRANITE field team when I officially joined the GEMM Lab this year in June. I had never flown a DJI Inspire quadcopter before (the drone used by the GEMM Lab), but with my foundation piloting different drones, some excellent guidance from Todd and Clara, and several hours of practice to get comfortable with the new setup, I was flying over my first gray whale by day three of the job.
The Oregon coast brings all sorts of weather, and some days I strangely found myself wearing a similar number of layers as I did in Antarctica. Fog, wind, and swell could all change within the hour, so I learned to make the most of weather breaks when they came. I was most surprised by how noticeably different gray whales behave compared to the blue, Antarctic minke, and humpback whales I had grown familiar with watching from above. For one, it is absolutely incredible to see how these huge whales use their low-aspect ratio flippers and flukes (Woodward et al., 2006) to perform low-speed, highly dynamic maneuvers to swim in very shallow water (5-10 m) so close to shore (<1m sometimes!) and through kelp forest or surf zones close to the beach. They have amazing proprioception, or the body’s ability to sense its movement, action, and position, as gray whales often use their pectoral fins and fluke to stay in a head standing position (see Clara Bird’s blog) to feed in the bottom sediment layer, all while staying in the same position and resisting the surge of waves that could smash them against the rocks (Video 1) . It is also remarkable how the GEMM Lab knows each individual whale based on natural skin marks, and I started to get a better sense of each whale’s behavior, including where certain individuals typically like to feed, or what their dive cycle might be depending on their feeding behavior.
Video 1. Two Pacific Coast Feeding Group (PCFG) gray whales “head-standing” in shallow waters off the coast of Newport, Oregon. NOAA/NMFS permit #21678
I feel very fortunate to be a part of the GRANITE field team and to contribute to data collection efforts. I look forward to the data analysis phase to see what we learn about how the morphology and behavior of these gray whales to help them thrive in their environment.
References:
Christiansen, F., Dujon, A. M., Sprogis, K. R., Arnould, J. P. Y., and Bejder, L. (2016).Noninvasive unmanned aerial vehicle provides estimates of the energetic cost of reproduction in humpback whales. Ecosphere 7, e01468–18.
Durban, J. W., Fearnbach, H., Barrett-Lennard, L. G., Perryman, W. L., & Leroi, D. J. (2015). Photogrammetry of killer whales using a small hexacopter launched at sea. Journal of Unmanned Vehicle Systems, 3(3), 131-135.
Durban, J. W., Moore, M. J., Chiang, G., Hickmott, L. S., Bocconcelli, A., Howes, G., et al.(2016). Photogrammetry of blue whales with an unmanned hexacopter. Mar. Mammal Sci. 32, 1510–1515.
Torres, L. G., Nieukirk, S. L., Lemos, L., & Chandler, T. E. (2018). Drone up! Quantifying whale behavior from a new perspective improves observational capacity. Frontiers in Marine Science, 5, 319.
Woodward, B. L., Winn, J. P., and Fish, F. E. (2006). Morphological specializations of baleen whales associated with hydrodynamic performance and ecological niche. J. Morphol. 267, 1284–1294.
Recently, when expected to choose a wildlife species for behavioral observation for one of my Oregon State University graduate courses, I immediately chose harbor seals as my focus. Harbor seals (Fig 1) are an abundant species and in proximity to the Hatfield Marine Science Center (HMSC) (Steingass et al., 2019) where I will be spending much of my time this summer, making logistics easy. Studying pinnipeds (marine mammals with a finned foot, seals, walrus, and sea lions) is appealing due to their undeniably cute physique, floppy nature on land, and super agile nature in the water. I am working to iron out my methods for this study, which I hope to work through in this initial phase of my research project.
Figure 1. Harbor seal hauling out to rest on rocks off Oregon Coast near HMSC.
Behaviors:
At times it can appear that the most interesting harbor seal behaviors occur under water, and the haul out time is simply time for resting. During mating season, most adult seal behaviors take place in the water, such as the incredible vocal acoustics displayed by the males to attract the females (Matthews et al., 2018). However, I hypothesize that young pups can capitalize on haul out time by practicing becoming adults (while the adults are taking that time to rest) and therefore I plan to observe their haul out behaviors in their first summer of life. Specifically, I will document seal pup vocal behavior to evaluate how they are learning to use sound. I am beginning this study in late July, which is just after pupping season (Granquist et al., 2016). This should give me the opportunity to find pups along the Oregon coast near HMSC, so I intend to visit several locations where harbor seals are known to frequently haul out. Knowing that field work and animal behavior is unpredictable, there is no telling what behaviors I will observe on a given day, or if I will see seals at all. Some days I could come home with lots of seal data and great photos, and other days I could come home with little to report. This will be my first hurdle combined with my time limit (strictly completing this observation in the next five weeks). I intend to schedule at least eight hours of field observation at haul-out sites over the next two weeks and will adjust my schedule based on my success in data collection at that point.
Figure 2. Harbor Seals hauling out on rocks not too far from HMSC.
Timing:
Prior knowledge on harbor seal haul-out sites along the Oregon coast is clearly important for this project’s success, but I must also pay close attention to the tide cycles. During low tides, haul out locations are exposed and occupied by seals. When the tide is high, the seals are less likely to haul-out (Patterson et al., 2008). Furthermore, according to a recent study conducted on harbor seals residing on the Oregon coast, these seals spend on average 71% of their time in the water and will haul-out for the remainder of their time (Steingass et al., 2019). Therefore, it is crucial to maximize my observation time of hauled out pups wisely.
Concerning timing, I also need to observe locations and periods without too many tourists who can get near the haul-out site. As I learned recently, when children show up and start throwing rocks into the water near where harbor seals are swimming, the seals will recede from the area and no longer be available for observation. As an experiment, I waited for the noisy crowds with unchecked children to leave and only myself, my trusty sidekick (my daughter), and one quiet photographer were left on the beach. Once that happened, we noticed more and more seal heads popping up out of the water. Then they came closer and closer to the beach, splashing around doing somersaults visibly on the surface of the water. It was quite a show. I will either need to account for the presence of humans when evaluating seal behavior or assess only periods without disturbance. Seal pups are easily disturbed by humans, so I will keep a non-invasive distance while positioning myself to hear the vocals.
Figure 3. Hauled-out adult harbor seal on the Oregon coast near HMSC.
Data Collection and Analysis Approach:
The aspect of this project I am still working out is how to quantify pup vocalizations and their associated behaviors. As I mentioned, I will go out each week for eight hours and record each time I notice a pup exhibiting vocal behavior. I will categorize and describe the sound produced by the pup, and document any associated behavior of the pup or behavioral responses from nearby adult seals. Prior research has found that harbor seals are much attuned to vocal behavior. Mother harbor seals learn to quickly distinguish their own pup’s call within a few days of their birth (Sauve et al. 2015). I hypothesize that pups themselves can discern and use vocalizations, and I am excited to watch them develop over the course of my field observations.
Figure 4. Seal pup on the far-left rock, watching the adults as they appear to rest.
References
Granquist, S.M., & Hauksson, E. (2016). Seasonal, meteorological, tidal, and diurnal effects on haul-out patterns of harbour seals (Phoca vitulina) in Iceland. Polar Biology, 39 (12), 2347-2359.
Matthews, L.P., Blades, B., Parks, S. (2018). Female harbor seal (Phoca vitulina) behavioral response to playbacks of underwater male acoustic advertisement displays. PeerJ, 6, e4547.
Patterson, J., Acevedo-Gutierrez, A. (2008). Tidal influence on the haul-out behavior of harbor seals (Phoca vitulina) At all time levels. Northwestern Naturalist, 89 (1), 17-23.
Sauve, C., Beauplet, G., Hammil, M., Charrier, I. (2015). Mother-pup vocal recognition in harbour seals: influence of maternal behavior, pup voice and habitat sound properties. Animal Behavior, 105 (July 2015), 109-120
Steingass, S., Horning, M., Bishop, A. (2019). Space use of Pacific harbor seals (Phoca vitulina richardii) from two haulout locations along the Oregon coast. PloS one. 14 (7), e0219484.
Allison Dawn, new GEMM Lab Master’s student, OSU Department of Fisheries, Wildlife and Conservation Sciences, Geospatial Ecology of Marine Megafauna Lab
While standing at the Stone Shelter at the Saint Perpetua Overlook in 2016, I took in the beauty of one of the many scenic gems along the Pacific Coast Highway. Despite being an East Coast native, I felt an unmistakable draw to Oregon. Everything I saw during that morning’s hike, from the misty fog that enshrouded evergreens and the ocean with mystery, to the giant banana slugs, felt at once foreign and a place I could call home. Out of all the places I visited along that Pacific Coast road trip, Oregon left the biggest impression on me.
Figure 1. View from the Stone Shelter at the Cape Perpetua Overlook, Yachats, OR. June 2016.
For my undergraduate thesis, which I recently defended in May 2021, I researched blue whale surface interval behavior. Surface interval events for oxygen replenishment and rest are a vital part of baleen whale feeding ecology, as it provides a recovery period before they perform their next foraging dive (Hazen et al., 2015; Roos et al., 2016). Despite spending so much time studying the importance of resting periods for mammals, that 2016 road trip was my last true extended resting period/vacation until, several years later in 2021, I took another road trip. This time it was across the country to move to the place that had enraptured me.
Now that I am settled in Corvallis, I have reflected on my journey to grad school and my recent road trip; both prepared me for a challenging and exciting new chapter as an incoming MSc student within the Marine Mammal Institute (MMI).
Part 1: Journey to Grad School
When I took that photo at the Cape Perpetua Overlook in 2016, I had just finished the first two semesters of my undergraduate degree at UNC Chapel Hill. As a first-generation, non-traditional student those were intense semesters as I made the transition from a working professional to full-time undergrad.
By the end of my freshman year I was debating exactly what to declare as my major, when one of my marine science TA’s, Colleen, (who is now Dr. Bove!), advised that I “collect experiences, not degrees.” I wrote this advice down in my day planner and have never forgotten it. Of course, obtaining a degree is important, but it is the experiences you have that help lead you in the right direction.
That advice was one of the many reasons I decided to participate in the Morehead City Field Site program, where UNC undergraduates spend a semester at the coast, living on the Duke Marine Lab’s campus in Beaufort, NC. During that semester, students take classes to fulfill a marine science minor while participating in hands-on research, including an honors thesis project. The experience of designing, carrying out, and defending my own project affirmed that graduate school in the marine sciences was right for me. As I move into my first graduate TA position this fall, I hope to pay forward that encouragement to other undergraduates who are making decisions about their own future path.
Figure 2. Final slide from my honors thesis defense. UNC undergraduates, and now fellow alumni, who participated in the Morehead City Field Site program in Fall 2018.
Part 2: Taking a Breather
Like the GEMM Lab’s other new master’s student Miranda, my road trip covered approximately 2,900 miles. I was solo for much of the drive, which meant there was no one to argue when I decided to binge listen to podcasts. My new favorite is How To Save A Planet, hosted by marine biologist Dr. Ayana Elizabeth Johnson and Alex Blumberg. At the end of each episode they provide a call to action & resources for listeners – I highly recommend this show to anyone interested in what you can do right now about climate change.
Along my trip I took a stop in Utah to visit my parents. I had never been to a desert basin before and engaged in many desert-related activities: visiting Zion National Park, hiking in 116-degree heat, and facing my fear of heights via cliff jumping.
Figure 3. Sandstone Rocks at Sand Hollow National Park, Hurricane, Utah. June 2021.
My parents wanted to help me settle into my new home, as parents do, so we drove the rest of the way to Oregon together. As this would be their first visit to the state, we strategically planned a trip to Crater Lake as our final scenic stop before heading into Corvallis.
Figure 4. Wizard Island in Crater Lake National Park, Klamath County, OR. June 2021.
This time off was filled with adventure, yet was restorative, and reminded me the importance of taking a break. I feel ready and refreshed for an intense summer of field work.
Part 3: Rested and Ready
Despite accumulating skills to do research in the field over the years, I have yet to do marine mammal field work (or even see a whale in person for that matter.) My mammal research experience included analyzing drone imagery, behind a computer, that had already been captured. As you can imagine, I am extremely excited to join the Port Orford team as part of the TOPAZ/JASPER projects this summer, collecting ecological data on gray whales and their prey. I will be learning the ropes from Lisa Hildebrand and soaking up as much information as possible as I will be taking over as lead for this project next year.
It will take some time before my master’s thesis is fully developed, but it will likely focus on assessing the environmental factors that influence gray whale zooplankton prey availability, and the subsequent impacts on whale movements and health. For five years, the Port Orford project has conducted GoPro drops at 12 sampling stations to collect data on zooplankton relative abundance.
Figures 5 & 6. GEMM GoPro drop stick assembly and footage demonstrating mysid data collection. July 2021.
Paired with this GoPro is a Time-Depth Recorder (TDR) that provides temperature and depth data. The 2021 addition to this GoPro system is a new dissolved oxygen (DO) sensor the GEMM Lab has just acquired. This new piece of equipment will add to the set of parameters we can analyze to describe what and how oceanographic factors drive prey variability and gray whale presence in our study site.My first task as a GEMM Lab student is to get to know this DO sensor, figure out how it works, set it up, test it, attach it to the GoPro device, and prepare it for data collection during the upcoming Port Orford project starting in 1 week!
Figure 7. The GEMM lab’s new RBR solo3 getting ready for Port Orford. July 2021.
Dissolved oxygen plays a vital role in the ocean; however, climate change and increased nutrient loading has caused the ocean to undergo deoxygenation. According to the IUCN’s 2019 Issues Brief, these factors have resulted in an oxygen decline of 2% since the middle of the 20th century, with most of this loss occurring within the first 1000 meters of the ocean. Two percent may not seem like much, but many species have a narrow oxygen threshold and, like pH changes in coral reef systems, even slight changes in DO can have an impact. Additionally, the first 1000 meters of the ocean contains the greatest amount of species richness and biodiversity.
Previous research done in a variety of systems (i.e., estuarine, marine, and freshwater lakes) shows that dissolved oxygen concentrations can have an impact on predator-prey interactions, where low dissolved oxygen results in decreased predation (Abrahams et al., 2007; Breitburg et al., 1997; Domenici et al., 2007; Kramer et al., 1987); and changes in DO also change prey vertical distributions (Decker et al., 2004). In Port Orford, we are interested in understanding the interplay of factors driving zooplankton community distribution and abundance while investigating the trophic interaction between gray whales and their prey.
I have spent some time with our new DO sensor and am looking forward to its first deployments in Port Orford! Stay tuned for updates from the field!
References
Abrahams, M. V., Mangel, M., & Hedges, K. (2007). Predator–prey interactions and changing environments: who benefits?. Philosophical Transactions of the Royal Society B: Biological Sciences, 362(1487), 2095-2104.
Breitburg, D. L., Loher, T., Pacey, C. A., & Gerstein, A. (1997). Varying effects of low dissolved oxygen on trophic interactions in an estuarine food web. Ecological Monographs, 67(4), 489-507.
Decker, M. B., Breitburg, D. L., & Purcell, J. E. (2004). Effects of low dissolved oxygen on zooplankton predation by the ctenophore Mnemiopsis leidyi. Marine Ecology Progress Series, 280, 163-172.
Domenici, P., Claireaux, G., & McKenzie, D. J. (2007). Environmental constraints upon locomotion and predator–prey interactions in aquatic organisms: an introduction.
Hazen, E. L., Friedlaender, A. S., & Goldbogen, J. A. (2015). Blue whales (Balaenoptera musculus) optimize foraging efficiency by balancing oxygen use and energy gain as a function of prey density. Science Advances, 1(9), e1500469.
Kramer, D. L. (1987). Dissolved oxygen and fish behavior. Environmental biology of fishes, 18(2), 81-92.
Roos, M. M., Wu, G. M., & Miller, P. J. (2016). The significance of respiration timing in the energetics estimates of free-ranging killer whales (Orcinus orca). Journal of Experimental Biology, 219(13), 2066-2077.
There are moments in our individual lifetimes that we can define as noteworthy and right now, as I prepare to start my graduate career within the Marine Mammal Institute (MMI) at OSU, I would say this is it for me. As I sit down to write this blog and document how surreal my future adventure is, I simultaneously feel this path is felicitous. After a year of being cooped up due to COVID, time presently seems to be going by at rocket speed. I am moving constantly in through my day to continue running my current life, while simultaneously arranging all that will encompass my new life. And while I answer questions to my 10-year-old daughter who is doing geometry homework in the living room, while hollering “That is not yours!” to the kitchen where the recently adopted feral dog is sticking his entire head under the trash can lid, while arranging our books in a cardboard box at the packing station I set up on the dining room table, I cannot deny a sense of serenity. This moment in my life, becoming a part of the GEMM Lab and MMI, and relocating to Corvallis is great.
This moment’s noteworthiness is emphasized by embarking on probably the most variable-heavy road trip I have planned to date. Since the age of 19, when I left my small mountain town on the Appalachian trail in Pennsylvania, I have transferred locations ~20 times. Due to extensive travel while serving in the Army (various Army trainings and overseas mission deployments), I have bounced around the US and to other countries often. Over time, one becomes acclimated to the hectic nature of this sort of lifestyle, and yet this new adventure holds significance.
So here are the details of the adventure trip that lies ahead: I will drive my 2002 Jeep Grand Cherokee across the country; from Charlottesville, Virginia to Corvallis, Oregon. My projected route will extend 2,822 miles and take ~43 driving hours total. The route will fall within the boundaries of 11 states (see Figure 1.)
Figure 1. Blue Line indicates route from Charlottesville to Corvallis (Google Maps)
Attached to the hitch of the Jeep will be a 6×12 rented cargo trailer containing our treasured books, furniture and things. Inside the Jeep will be three living variables: Mia (the 10-year-old), Angus (hyperactive border collie/ pit bull mix) and Mr. Gibbs (feral pirate dog); all three will need to be closely monitored for potential hiccups in the plan.
If we are going to make it to our destination hotel/Airbnb each night of the trip, I must be organized and calculate road time each day while factoring in breaks to the loo and fueling up. These calculations need to be precise, with little margin for error. I cannot play it too safely either, or it will take us too long to get across the country (I must start my graduate work after all). On the other hand, I cannot realistically expect too many road hours in a day. I think at this point I have got it worked out (Table 1.)
Table 1. Driving Hours and Miles Per Day
When I look back on my career, I had no idea that my not-so-smooth road would lead me to my dream goal of studying marine mammals. I took the Army placement tests at the age of 19, which led me to the field of “information operations” where I earned a great knowledge base in data analysis and encountered fantastic leaders whom I might not have known otherwise. I learned immensely on this path and it set me up very well for moving forward into research and collaboration in the sciences. I am so grateful that my life took this journey because working in the military provided me with the utmost respect for my opportunities and greater empathy for others. This route had many extreme obstacles and was intensely intimidating at times, but I am all the better for it. And I was never able to shake the dream of where I wanted to be (see Figures 2 & 3.) Timing is everything.
Figure 2 & 3. Two of the images of the Pacific coast I have hung up in my house. Keeping my eye on the prize, so to speak.
It will feel great to cross over the Oregon state line. I cannot wait to meet GEMM Lab in-person and all the other wonderful researchers and staff at MMI and Hatfield Marine Science Center. I am eager to step onto the RV Pacific Storm and begin my thesis research on the magnificent cetaceans off the Oregon coast, and hopefully do some good in the end. As I evaluate the logistics of my trip from Charlottesville to Corvallis, I feel relieved rather than overwhelmed. We could attribute this relief to my not-so-smooth road to get to where I am. Looking ahead, of course, I see a road that will require focus, attention, passion, care, and lots of fuel. Even if this road is not completely smooth, I will have my hands on 10 and 2, and feel so grateful and ready to be on it.
As I solidified my grad school plans last spring, one of the things that made me most excited to join the GEMM Lab was the direct applicability of its research to management and conservation practices. Seeing research directly plugged into current problems facing society is always inspirational to me. My graduate research will be part of the GEMM Lab’s project to identify co-occurrence between whales and fishing effort in Oregon, with the goal of helping to reduce whale entanglement risk. Recently, watching the Oregon Department of Fish and Wildlife (ODFW) Commission in action gave me a fascinating, direct look at how the management sausage gets made.
Two humpback whales surface together off the coast of Oregon. Photo taken under NOAA/NMFS research permit #21678.
At the September Commission meeting, ODFW Marine Resources Program Manager Caren Braby presented proposed rule changes in the management of the Oregon dungeness crab fleet. As part of a coordinated effort with Washington and California, the main goal of these changes is to reduce the risk of whale entanglements, which have increased sharply in US West Coast waters since 2014.
With the aim of maximizing the benefit to whales while minimizing change to the fishery, Braby and her staff developed a recommendation for a shift in summer fishing effort, when whales are most abundant in Oregon waters. Based on diverse considerations — including the distributions of humpback whales off Oregon and season fishery economics — she outlined options along what she termed a “spectrum of reduced risk,” which included possible shifts in the fishing season, spatial extent, and number of pots deployed.
Although the GEMM Lab project to provide a robust understanding of whale distribution in Oregon waters is not yet complete, the data collected to-date has already significantly refined knowledge of whale distributions off the coast — and it directly informed the proposed monthly depth limitations for fishing effort. It is never possible to have perfect knowledge of an ecosystem, and resource managers must navigate this inherent complexity as they make decisions. As the GEMM Lab collects and analyzes more data on the distribution of whales and their prey, our ability to inform management decisions can become even more precise and effective.
Braby proposed that the fleet reduce the number of crab pots deployed by 20% and prohibit fishing at depths greater than 30 fathoms, starting May 1, for the next three seasons. The goal of this recommendation is to effectively separate the bulk of fishing effort from the deep waters where humpback whales forage, when they visit their feeding grounds off the coast of Oregon during the summer.
ODFW Marine Resources Program Manager Caren Braby outlined management options along a “spectrum of reduced risk.” Source: ODFW
Following Braby’s presentation, a public comment period allowed stakeholders to offer their own opinions and requests for the Commission to consider. Fisherman, lawyers, and members of conservation nonprofits each provided succinct three-minute statements, offering a wide range of opinions and amendments to the proposed rule changes.
This comment period highlighted how truly multifaceted this decision-making process is, as well as the huge number of livelihoods, economic impacts, and types of data that must be considered. It also raised essential questions — how do you make regulations that protect whales without favoring one group of stakeholders over another? How can you balance multiple levels of law with the needs of local communities?
Even during heated moments of this meeting, the tone of the dialog impressed me. This topic is inevitably a contentious and emotional issue. Yet even people with opposing viewpoints maintained focus on their common goals and common ground, and frequently reiterated their desire to work together.
After more than six hours of presentations, comments, and deliberation, the Commission voted on the proposed rule changes. They decided to adopt somewhat more liberal rule changes than Braby had proposed — a 20% reduction in crab pots and a prohibition on fishing at depths greater than 40 fathoms, starting May 1. After three years, the Commission will evaluate the efficacy of these new policies, and plan to refine or change the rules based on the best available data.
Witnessing this decision-making process gave me a new perspective on the questions and context my research will fit into, and this understanding will help me become a better collaborator. Watching the Commission in action also underscored the difficult position managers are often put in. They must make decisions based on incomplete knowledge that will inevitably impact people’s lives — but they also need to protect the species and biodiversity, that also have an innate right to exist in natural ecosystems. Seeing the intricacies of this balancing act made me glad that I get to be part of research that can inform important management decisions in Oregon.
ODFW Marine Resources Program Manager Caren Braby’s presentation begins around an hour and 52 minutes into the video, and it is followed by a question and answer session and public testimony.
Fall has arrived in the Pacific Northwest. For humans, it means packing away the shorts and sandals, and getting the boots, raincoats and firewood ready. For gray whales, it means gulping down the last meal of zooplankton they will eat for several months and commencing the journey to warmer waters and sunnier skies in Mexico where they will spend the winter fasting, calving, and nursing. While the GEMM Lab may still squeeze in a day or two of field work this week, we are slowly wrapping up the 2020 field season as conditions get rougher and our beloved gray whales gradually depart our waters. This year marked the 6th year of data collection for both of our gray whale projects: the Newport project that investigates the impacts of multiple stressors on gray whale ecology and health, and the Port Orford project that explores fine-scale foraging ecology of gray whales and their zooplankton prey. Since it will be several months before the GEMM Lab heads back out onto the water again, I thought I would summarize our two field seasons, share some highlights, and muse about the drivers of our observations this summer.
Some snapshots of the field team hard at work this summer. Top left: Hunter Warwick operating the drone. Top right: PI Leigh Torres rocking the lab swag to protect against the sun. Bottom left: Lisa Hildebrand waiting for a whale to surface to get photos of it. Bottom right: Alejandro Fernandez Ajo transfers zooplankton from the light trap to sample jars.
Summaries
Our RHIB Ruby zipped around the central and southern Oregon coast on 33 different days. The summer started slow, with several days of field work where we encountered no whales despite surveying our entire study region. Our encounters picked up towards the end of June and by the end of the summer we totaled 107 sightings, encountering 46 unique individuals, 36 of which were resightings of known individuals we have identified in previous years. Our Newport star of the summer was Solé, a female gray whale we have seen every year since 2015, and we also saw many of our other regulars including Casper, Rafael, Spray, Bit, and Heart. None of these whales shone as bright as Solé though. We flew the drone over her 8 times and collected 7 fecal samples (one of which was the biggest whale fecal sample I have ever seen!). In total, we collected 30 fecal samples and flew the drone 88 times. These data will allow us to continue measuring body condition and hormone levels of Pacific Coast Feeding Group (PCFG) gray whales that use the Oregon coast.
Left: Our RHIB Ruby heading out for a day of field work in Port Orford, OR this summer. Right: Solé. Image captured under NOAA/NMFS permit #21678.
Our tandem research kayak Robustus may not be as zippy as Ruby (it is powered by human muscle rather than a powerful outboard engine after all), but it certainly continues to be a trusty vessel for the Port Orford team. The Port Orford research team, named the Theyodelers this year, collected 181 zooplankton samples and conducted 180 GoPro drops during the month of August from Robustus. Despite the many samples collected, the size of our prey samples remained relatively small throughout the whole season compared to previous years. The cliff team surveyed for a total of 117 hours, of which 15 were spent tracking whales with the theodolite and resulted in 40 different tracklines of whale movements. The whale situation in Port Orford was similar to the pattern of whale sightings in Newport, with low whale sightings at the start of the field season. Luckily, by the start of August (which marked the start of data collection for the Theyodelers), the number of whales using the Port Orford area, especially the two study sites, Mill Rocks & Tichenor Cove, had increased. Of the whales that came close enough to shore for us to identify using photo-id, we tracked 5 unique individuals, 3 of which we also saw in Newport this year. The Port Orford star of the summer was Smudge, with his tracklines making up a quarter of all of our tracklines collected. Smudge is also the whale we sighted most often last year in Port Orford.
Top: Theyodelers Mattea Holt Colberg and Liz Kelly sampling atop the kayak Robustus. Bottom: Smudge. Image captured under NOAA/NMFS permit #21678.
Highlights
Many of you may be familiar with the whale Scarlett (formally known as Scarback). Scarlett is a female, at least 24 years old (she was first documented in the PCFG range in 1996), who is well-known (and easily identified) by the large concave injury on her back that is covered in whale lice, or cyamids. No one knows for certain how Scarlett sustained this injury (though there are stories), however what we do know is that it has not prevented this female from reproducing and successfully raising several calves over her lifetime. The GEMM Lab last saw Scarlett with a calf (which we named Brown) in 2016. Since Scarlett is such a famous whale with a unique history, it shouldn’t be a surprise that one of our highlights this summer is the fact that Scarlett showed up with a new calf! In keeping with a “shades of red” theme, Leigh came up with the name Rose for the new calf. In July, the mom-calf pair put on quite a cute performance, with Rose rising up on Scarlett’s back, giving the team a glimpse of its face. The Scarlett-Rose highlight doesn’t end there though. Just last week, we had a very brief encounter in choppy, swelly waters with a small whale. The whale surfaced just twice allowing us to capture photo-id images, and as we were looking around to see where it would come up a third time, it suddenly breached approximately 20 m from the boat. Lo-and-behold, after comparing our photos of the whale to our catalogue, we realized that this elusive, breaching whale was Rose! I am excited to see whether Rose will return to the Oregon coast next summer and become a PCFG regular just like her mom.
Top: Scarlett, easily identified by the large concave injury on her back covered in cyamids. Bottom: Scarlett with her new calf Rose riding her back, giving us a glimpse of its face. Images captures under NOAA/NMFS permit #21678.
The highlight of the field season in Port Orford is the trial, failures and small successes of a new element to the project. There is still a lot that we do not know and understand about PCFG gray whales. One such thing is the way in which gray whales maneuver their large bodies in shallow rocky habitats, often riddled with kelp, and how exactly they capture their zooplankton prey in these environments. Using drones has certainly helped bring some light into this darkness and has led to the documentation of many novel foraging behaviors (Torres et al. 2018). However, the view from above is unable to provide the fine-scale interactions between whales, kelp, reefs, and zooplankton. Instead, we must somehow find a way to watch the whales underwater. Enter CamDo. CamDo is a technology company that designs specialty products to allow for GoPro cameras to be used for time-lapsed recordings over long periods of time in harsh environmental conditions. One of their products is a housing specifically designed for long-term filming underwater – exactly what we need! The journey was not as easy as simply purchasing the housing. We also needed to build a lander for the housing to sit on (thankfully our very own Todd Chandler designed and built something for us), and coordinate with divers and a vessel to deploy and retrieve the set-up, as well as undertake weekly battery and SD cards swaps (thankfully Dave Lacey of South Coast Tours and a very generous group of divers* donated their time and resources to make this happen). We unfortunately had some technological difficulties and bad visibility for the first 4 weeks (precisely why this CamDo effort was a pilot season this year), however we had some small success in the last 2 weeks of deployment that give us hope for the future. The camera recorded a lot of things: thick layers of mysids, countless rockfish and lingcod, several swimming and foraging murres, a handful of harbor seals, and two encounters of the species we were hoping to film – gray whales! While the footage is not the ‘money shot’ we are hoping to film (aka, a headstanding gray whale eating zooplankton right in front of the camera), the fact that we captured gray whales in the first place has showed us that this set-up is a promising investment of time, money and effort that will hopefully deliver next year.
Top left: CamDo atop its lander designed and built by Todd Chandler. Top right: Divers getting ready to get into the water for a battery and SD card swap. Bottom: Dave Lacey and two of our divers with the Black Pearl, South Coast Tour’s boat.
Musings
You may have picked up on the fact that we had slow starts to our field seasons in both Newport and Port Orford. Furthermore, while the number of whale sightings did increase in both locations throughout the field seasons, the number of sightings and whales per day were lower than they have been in previous years. For example, in 2018, we identified 15 different individuals in the month of August in Port Orford (compared to just 5 this year). In 2019, 63 unique whales were seen in Newport (compared to 46 this year). Interestingly, we had a greater diversity of encountered individuals at the start and end of the season in Newport, with a relatively small number of different individuals in July and August. While I cannot provide a definitive reason (or reasons) as to why patterns were observed (we will need to analyze several years of our data to try and understand why), I have some hypotheses I wish to share with you.
As I mentioned in a previous blog, this summer the coastal upwelling along the Oregon coast was delayed (Figure 1). Typically, peak upwelling occurs during the month of June or shortly thereafter, bringing nutrient-rich, deep waters to the surface and, when mixed with sunlight, a lot of productivity. This productivity sets off a chain of reactions — the input of nutrients leads to increased phytoplankton production, which in turn leads to increased zooplankton production, resulting in growth and development of larger organisms that consume zooplankton, such as rockfish and gray whales. If the timing of upwelling is delayed, then so too is this chain of reactions. As you can see from Figure 1, the red lines show that the peak upwelling this year occurred far later in the summer than any year in the last 10 years, with the exception of 2012. Gray whales may have cued into this delay and therefore also delayed their arrival to the PCFG feeding grounds, hence causing us to have low sighting rates at the start of our season. However, this is mostly speculative as we still do not understand the functional mechanisms by which cetaceans, such as gray whales, detect prey across different scales, and to what extent oceanographic conditions like upwelling may play a role in prey availability (Torres 2017).
Figure 1. 10 year time series of the Coastal Upwelling Transport Index (CUTI). CUTI represents the amount of upwelling (positive numbers) or downwelling (negative numbers). The light-colored lines representthe CUTI at that point in time while the dark, bold line represents the long-term average.The vertical red lines represent the point of peak upwelling in that summer and the horizontal green line shows the peak level of upwelling in 2020 relative to all previous years.
Furthermore, the green line in Figure 1shows that even after peak upwelling was reached this year, upwelling conditions were lower than all the other peaks in the previous 10 years. We know that weak upwelling is correlated to poor body condition of PCFG gray whales in subsequent years (Soledade Lemos et al. 2020). Upon arriving to the Oregon coast feeding grounds, gray whales may have noticed that it was shaping up to be a poor prey year (we certainly noticed it in Port Orford in the emptiness of our zooplankton net). Faced with this low resource availability, individuals had to make important decisions – risk staying in a currently prey-poor environment or continue the journey onward, searching for better prey conditions elsewhere. This conundrum is known as the marginal value theorem, whereby an individual must decide whether it should abandon the patch it is currently foraging on and move on to search for a new patch without knowing how far away the next patch may be or its value relative to the current patch (Charnov 1976). If we think of the Oregon coast as the ‘current patch’, then we can see how the marginal value theorem translates to the situation gray whales may have found themselves in at the start of the summer.
Yet, an individual gray whale does not make these decisions in a vacuum. Instead, all gray whales in the same area are faced with the same conundrum. Seminal work by Pianka (1974) showed that when resources, such as food, are abundant, then competition between predators is low because there is enough food to go around. However, when resources dwindle, competition increases and the niches of predators begin to overlap more and more. With Charnov and Pianka’s theories in mind, we can see two groups of gray whales emerge from our 2020 field work observations: those that stayed in the ‘current patch’ (Oregon) and those that decided to seek out a new patch in hopes that it would be a better one. Solé certainly belongs in the first group. We saw her consistently throughout the whole summer. In fact, she was oftentimes so predictable that we would find her foraging on the same reef complex every time we went out to survey. Smudge may also belong in this group, however it is hard to say definitively since we only survey in Port Orford in late July and August. In contrast, I would place whales such as Spray and Heart in the second group since we saw them early in the summer and then not again until mid-to-late September. Where did they go in the interim? Did they go somewhere else in the PCFG range? Or did they venture all the way up to Alaska to the primary Eastern North Pacific (ENP) gray whale feeding grounds? Did their choice to search for food elsewhere pay off?
As I said earlier, these are all just musings for now, but the GEMM Lab is already hard at work trying to answer these questions. Stay tuned to see what we find!
* Thanks to all the divers who assisted with the pilot CamDo season: Aaron Galloway, Ross Whippo, Svetlana Maslakova, Taylor Eaton, Cori Kane, Austin Williams, Justin Smith
References
Charnov, E.L. 1976. Optimal Foraging, the Marginal Value Theorem. Theoretical Population Biology 9(2):129-136.
Pianka, E.R. 1974. Niche Overlap and Diffuse Competition. PNAS 71(5):2141-2145.
Soledade Lemos, L., Burnett, J.D., Chandler, T.E., Sumich, J.L., and L.G. Torres. 2020. Intra- and inter-annual variation in gray whale body condition on a foraging ground. Ecosphere 11(4):e03094.
Torres, L.G. 2017. A sense of scale: Foraging cetaceans’ use of scale-dependent multimodal sensory systems. Marine Mammal Science 33(4):1170-1193.
Torres, L.G., Nieukirk, S.L., Lemos, L., and T.E. Chandler. 2018. Drone Up! Quantifying Whale Behavior From a New Perspective Improves Observational Capacity. Frontiers in Marine Science: https://doi.org/10.3389/fmars.2018.00319.
When humans count calories it is typically to regulate and limit calorie intake. What I am wondering about is whether gray whales are aware of caloric differences in the prey that is available to them and whether they make foraging decisions based on those differences. In last week’s post, Dawn discussed what makes a good meal for a hungry blue whale. She discussed that total prey biomass of a patch, as well as how densely aggregated that patch is, are the important factors when a blue whale is picking its next meal. If these factors are important for blue whales, is it same for gray whales? Why even consider the caloric value of their prey?
Gray and blue whales are different in many ways; one way is that blue whales are krill specialists whereas gray whales are more flexible foragers. The Pacific Coast Feeding Group (PCFG) of gray whales in particular are known to pursue a more varied menu. Previous studies along the PCFG range have documented gray whales feeding on mysid shrimp (Darling et al. 1998;Newell 2009), amphipods (Oliver et al. 1984; Darling et al. 1998), cumacean shrimp (Jenkinson 2001; Moore et al. 2007;Gosho et al. 2011), and porcelain crab larvae (Dunham and Duffus 2002), to name a few. Based on our observations in the field and from our drone footage, we have observed gray whales feeding on reefs (likely on mysid shrimp), benthically (likely on burrowing amphipods), and at the surface on crab larvae (Fig. 1). Therefore, while both blue and PCFG whales must make decisions about prey patch quality based on biomass and density of the prey, gray whales have an extra decision to make based on prey type since their prey menu items occupy different habitats that require different feeding tactics and amount of energy to acquire them. In light of these reasons, I hypothesize that prey caloric value factors into their decision of prey patch selection.
Figure 1. Gray whales use several feeding tactics to obtain a variety of coastal Oregon zooplankton prey including jaw snapping (0:12 of video), drooling mud (0:21), and head standing (0:32), to name a few.
This prey selection process is crucial since PCFG gray whales only have about 6 months to consume all the food they need to migrate and reproduce (even less for the Eastern North Pacific (ENP) gray whales since their journey to their Arctic feeding grounds is much longer). You may be asking, well if feeding is so important to gray whales, then why not eat everything they come across? Surely, if they ate every prey item they swam by, then they would be fine. The reason it isn’t quite this simple is because there are energetic costs to travel to, search for, and consume food. If an individual whale simply eats what is closest (a small, poor-quality prey patch) and uses up more energy than it gains, it may be missing out on a much more beneficial and rewarding prey patch that is a little further away (that patch may disperse or another whale may eat it by the time this whale gets there). Scientists have pondered this decision-making process in predators for a long time. These ponderances are best summed up by two central theories: the optimal foraging theory (MacArthur & Pianka 1966) and the marginal value theorem (Charnov 1976). If you are a frequent reader of the blog, you have probably heard these terms once or twice before as a lot of the questions we ask in the GEMM Lab can be traced back to these concepts.
Optimal foraging theory (OFT) states that a predator should pick the most beneficial resource for the lowest cost, thereby maximizing the net energy gained. So, a gray whale should pick a prey patch where it knows that it will gain more energy from consuming the prey in the patch than it will lose energy in the process of searching for and feeding on it. Marginal value theorem elaborates on this OFT concept by adding that the predator also needs to consider the cost of giving up a prey patch to search for a new one, which may or may not end up being more profitable or which may take a very long time to find (and therefore cost more energy).
The second chapter of my thesis will investigate whether individual gray whales have foraging preferences by relating feeding location to prey quality (community composition) and quantity (relative density). However, in order to do that, I first must know about the quality of the individual prey species, which is why my first chapter explores the caloric content of common coastal zooplankton species in Oregon that may serve as gray whale prey. The lab work and analysis for that chapter are completed and I am in the process of writing it up for publication. Preliminary results (Fig. 2) show variation in caloric content between species (represented by different colors) and reproductive stages (represented by different shapes), with a potential increasing trend throughout the summer. These results suggest that some species and reproductive stages may be less profitable than others based solely on caloric content.
Figure 2. Mean caloric content (J/mg) of coastal Oregon zooplankton (error bars represent standard deviation) from May-October in 2017-2018. Colors represent species and shapes represent reproductive stage.
Now that we have established that there may be bigger benefits to feeding on some species over others, we have to consider the availability of these zooplankton species to PCFG whales. Availability can be thought of in two ways: 1) is the prey species present and at high enough densities to make searching and foraging profitable, and 2) is the prey species in a habitat or depth that is accessible to the whale at a reasonable energetic cost? Some prey species, such as crab larvae, are not available at all times of the summer. Their reproductive cycles are pulsed (Roegner et al. 2007) and therefore these prey species are less available than species, such as mysid shrimp, that have more continuous reproduction (Mauchline 1980). Mysid shrimp appear to seek refuge on reefs in rock crevices and among kelp, whereas amphipods often burrow in soft sediment. Both of these habitat types present different challenges and energetic costs to a foraging gray whale; it may take more time and energy to dislodge mysids from a reef, but the payout will be bigger in terms of caloric gain than if the whale decides to sift through soft sediment on the seafloor to feed on amphipods. This benthic feeding tactic may potentially be a less costly foraging tactic for PCFG whales, but the reward is a less profitable prey item.
My first chapter will extend our findings on the caloric content of Oregon coastal zooplankton to facilitate a comparison to the caloric values of the main ampeliscid amphipod prey of ENP gray whales feeding in the Arctic. Through this comparison I hope to assess the trade-offs of being a PCFG whale rather than an ENP whale that completes the full migration cycle to the primary summer feeding grounds in the Arctic.
References
Charnov, E. L. 1976. Optimal foraging: the marginal value theorem. Theoretical Population Biology 9:129-136.
Darling, J. D., Keogh, K. E. and T. E. Steeves. 1998. Gray whale (Eschrichtius robustus) habitat utilization and prey species off Vancouver Island, B.C. Marine Mammal Science 14(4):692-720.
Dunham, J. S. and D. A. Duffus. 2002. Diet of gray whales (Eschrichtius robustus) in Clayoquot Sound, British Columbia, Canada. Marine Mammal Science 18(2):419-437.
Gosho, M., Gearin, P. J., Jenkinson, R. S., Laake, J. L., Mazzuca, L., Kubiak, D., Calambokidis, J. C., Megill, W. M., Gisborne, B., Goley, D., Tombach, C., Darling, J. D. and V. Deecke. 2011. SC/M11/AWMP2 submitted to International Whaling Commission Scientific Committee.
Jenkinson, R. S. 2001. Gray whale (Eschrichtius robustus) prey availability and feeding ecology in Northern California, 1999-2000. Master’s thesis, Humboldt State University.
MacArthur, R. H., and E. R. Pianka. 1966. On optimal use of a patchy environment. American Naturalist 100:603-609.
Mauchline, J. 1980. The larvae and reproduction in Blaxter, J. H. S., Russell, F. S., and M. Yonge, eds. Advances in Marine Biology vol. 18. Academic Press, London.
Moore, S. E., Wynne, K. M., Kinney, J. C., and C. M. Grebmeier. 2007. Gray whale occurrence and forage southeast of Kodiak Island, Alaska. Marine Mammal Science 23(2)419-428.
Newell, C. L. 2009. Ecological interrelationships between summer resident gray whales (Eschrichtius robustus) and their prey, mysid shrimp (Holmesimysis sculpta and Neomysis rayii) along the central Oregon coast. Master’s thesis, Oregon State University.
Oliver, J. S., Slattery, P. N., Silberstein, M. A., and E. F. O’Connor. 1984. Gray whale feeding on dense ampeliscid amphipod communities near Bamfield, British Columbia. Canadian Journal of Zoology 62:41-49.
Roegner, G. C., Armstrong, D. A., and A. L. Shanks. 2007. Wind and tidal influences on larval crab recruitment to an Oregon estuary. Marine Ecology Progress Series 351:177-188.
By Mattea Holt Colberg, GEMM Lab summer intern, OSU junior
Science is about asking new questions in order to make new discoveries. Starting every investigation with a question, sparked by an observation, is enshrined in the scientific method and pursued by researchers everywhere. Asking questions goes beyond scientific research though; it is the best way to learn new things in any setting.
When I first arrived in Port Orford, I did not know much about gray whales. The extent of my knowledge was that they are large baleen whales that migrate every year and feed on plankton. I did, however, know quite a bit about killer whales. I have been interested in killer whales since I was 5 years old, so I have spent years reading about, watching, and listening to them (my current favorite book about them is Of Orcas and Men, by David Neiwert and I highly recommend it!). I have also had opportunities to research them in the Salish Sea, both on a sailing trip and through the dual-enrollment program Ocean Research College Academy, where I explored how killer whales respond to ambient underwater noise for a small independent project. Knowing more about killer whales than other species has caused killer whales to be the lens through which I approach learning and asking questions about other whales.
Figure 1a. Killer whales traveling in a group in the Salish Sea. Source: ISTOCK.
Figure 1b. A gray whale traveling solo in Tichenor Cove. Source: GEMM Lab.
At first, I was not sure how to apply what I know about killer whales specifically to research on gray whales, since killer whales are toothed whales, while gray whales are baleen whales. There are several differences between toothed whales and baleen whales; toothed whales tend to be more social, occurring in pods or groups, eat larger prey like fish, squid, and seals, and they echolocate. In comparison, baleen whales are less social, eat mostly tiny zooplankton prey, and do not echolocate. Because of these differences, I wanted to learn more about gray whales, so I started asking Lisa questions. Killer whales only sleep with half of their brain at a time, so I asked if gray whales do the same. They do. Killer whales typically travel in stable, long-term matriarchal groups, and I recently learned that gray whales frequently travel alone (though not exclusively). This new knowledge to me led me to ask if gray whales vocalize while traveling. They typically do not. Through asking these questions, and others, I have begun to learn more about gray whales.
Figure 2. Mattea on the tandem research kayak taking a break in between prey sampling. Source: L. Hildebrand.
I am still learning about marine mammal research, and from what I have experienced so far, marine mammal acoustics intrigues me the most. As a child, I developed a general interest in whale vocalizations after hearing recordings of them in museums and aquariums. Then, two years ago, I heard orcas vocalizing in the wild, and I decided I wanted to learn more about their vocalizations as a long-term career goal.
To pursue a career studying marine mammal acoustics, I will need scientific and communication skills that this internship is helping me develop. Sitting on the cliff for hours at a time, sometimes with gray whales swimming in our view-scape and sometimes without, is teaching me the patience and attention needed to review hours of sound recordings with or without vocalizations. Identifying and counting zooplankton most days is teaching me the importance of processing data regularly, so it does not build up or get too confusing, as well as attention to detail and keeping focused. Collecting data from a kayak is teaching me how to assess ocean conditions, keep track of gear, and stay calm when things go wrong. I am also practicing the skill of taking and identifying whale photos, which can be applied to many whale research topics I hope to pursue. Through writing this blog post and discussing the project with Lisa and my fellow interns, I am improving my science communication skills.
Figure 3. Mattea manning the theodolite watching and waiting for a gray whale to show up in our study area. Source: L. Hildebrand.
As an undergraduate student, it can sometimes be difficult to find opportunities to research marine mammals, so I am very grateful for and excited about this internship, both because of the skills it is helping me build and the field work experiences that I enjoy participating in. Another aspect of research this internship is helping me learn about is to ask engaging questions. As I mentioned at the beginning of this post, asking questions is a key element of conducting research. By asking questions about gray whales based on both prior knowledge and new observations, I am practicing this skill, as well as thinking of topics I am curious about and might want to explore in the future. While watching for whales, I have thought of questions such as: How is whale behavior affected by surface conditions? Do gray whales prefer feeding at certain times of the day? Questions like these help me learn about whales, and they keep me excited about research. Thanks to this internship, I can continue working towards my dreams of pursuing similar questions about whales as a career.
