Author: Lisa Hildebrand

GEMM Lab 2020: A Year in the Life

By Lisa Hildebrand, PhD student, OSU Department of Fisheries & Wildlife, Geospatial Ecology of Marine Megafauna Lab

Despite the trials and tribulations of 2020, the GEMM Lab has persevered and experienced many successes and high points. Join me, perhaps with a holiday beverage of choice in-hand, for a summary of what the lab and its members have achieved this year.

The GEMM Lab celebrated several milestones this year. We were all extremely excited and proud when halfway through the year, in July, GEMM Lab PI, Dr. Leigh Torres, was promoted to Associate Professor and granted indefinite tenure in the Department of Fisheries & Wildlife. Leigh joined the department in 2014 and has since completed 13 research projects, is leading 10 current research projects, has graduated 7 graduate students, and is currently advising 4 PhD students and a postdoctoral scholar. A big hurrah to Leigh, our inspiring and tireless captain at the GEMM Lab helm!!

Leigh isn’t the only GEMM Lab member to have received a new title. In March, Leila successfully defended her PhD thesis entitled “Body condition and hormone assessment of eastern North pacific gray whales (Eschrichtius robustus) and associations to ambient noise” and thus graduated from being a PhD candidate to being Dr. Leila Soledade Lemos. Leila is currently a postdoctoral associate at Florida International University. I (Lisa Hildebrand) defended my Master’s thesis “Tonight’s specials include mysids, amphipods, and more: An examination of the zooplankton prey of Oregon gray whales and its impact on foraging choices and prey selection” just a few weeks ago and now bear the title of Master of Science. I am excited to announce that I won’t be leaving the GEMM Lab anytime soon as I will continue to  work with Leigh as I pursue my PhD. Our final new title recipient is Dawn who at the start of December advanced to PhD candidacy after successfully passing her written comprehensive exams in mid-November and her oral comprehensive exams in early December.

  • Leila during her socially-distanced PhD defense seminar. Source: L. Torres.
  • Lisa during her Zoom Master’s defense seminar. Source: L. Hildebrand

Summer is a busy time in the GEMM Lab, largely because it is the time when gray whales are distributed along our Oregon coast for their feeding season and therefore when both of our gray whale projects (GRANITE, or Gray whale Response to Ambient Noise Informed by Technology and Ecology, and the Port Orford foraging ecology project) collect another year of data. With the COVID-19 pandemic in its early stages in the spring (when we start to prep for our field seasons), it was uncertain whether we would be able to get into the field at all. However, after weeks of drafting up and submitting COVID-19 safety plans and precautions, Leigh was able to get both of our gray whale field seasons approved to go ahead this summer! This task was not easy since both projects require some form of travel and sampling methods that do not always allow for 6-feet of distance between team members. Furthermore, the Port Orford project requires the whole team to live and work out of OSU’s Port Orford Field Station together. Despite the hurdles, both projects had successful field seasons. If you want to hear more about the specifics of the field seasons, check out the field season summary blog.

Gray whales weren’t the only species to grab our attention in the field this year. OPAL (Overlap Predictions about Large whales) had a successful second year with Leigh and MMI faculty research assistant Craig Hayslip taking to the skies in United States Coast Guard helicopters four times a month. The project seeks to identify co-occurrence between whales and fishing effort in Oregon to reduce entanglement risk. Leigh and Craig documented numerous cetacean species including blue, fin, humpback, sperm whales, and killer whales. To help with this work, we are so excited to officially have Solène Derville back in the GEMM Lab as a postdoctoral scholar who will work on statistical models aimed at predicting habitat use and distribution patterns of whales off the Oregon coast. While our wish to physically welcome Solène back to Oregon this year did not quite pan out, we are hopeful that she will make the journey from New Caledonia to Oregon in 2021!

The data collected during the helicopter flights will be complimented by the marine mammal observer data that various members of the GEMM Lab have collected over the last four years aboard NOAA Ship Bell M. Shimada as part of the Northern California Current Ecosystem survey. These surveys typically occur three times a year (February, May, September). Although the pandemic threw a wrench into the May cruise, the September cruise was able to go ahead with Dawn and Clara on-board as the two marine mammal observers. It was a very successful cruise, with abundant marine mammal sightings and good survey conditions. Read more about those cruises in Clara and Dawn’s blogs.

While the GEMM Lab did not undertake any field work in New Zealand this year, Leigh and Dawn did travel there in February to meet with scientific colleagues, representatives of the oil and gas industry, and environmental managers, including the New Zealand Minister of Conservation, the Honorable Eugenie Sage. The trip allowed Leigh and Dawn to present their research on blue whales and discuss management implications. These meetings have been highly beneficial as they shared their latest research and results to assist with the development of a marine mammal sanctuary within the industrial region where their research is conducted.

The GEMM Lab prides itself on having strong outreach components to our research, ensuring that young students (high school and undergraduate) from diverse backgrounds have an opportunity to learn STEM skills. Some outreach opportunities were not possible in 2020, but the GEMM Lab continued our efforts where possible. Clara taught a photogrammetry workshop for the Marine Studies Initiative student club Ocean11, where students were taught how to measure whales from drone images. The success of the workshop (and earlier iterations of it in 2019) led to Clara turning it into a lab for Dr. Renee Albertson’s FW 469 Physiology/Behavior of Marine Megafauna class. As one of the program coordinators for the Fisheries & Wildlife Mentorship Program, I co-hosted an Intro to R & RStudio workshop this fall. Rachel taught a remote intensive science communication workshop during her first term in grad school. Although COVID-19 meant that one-on-one mentorships had to be a little more distant, over the course of the year, the GEMM Lab still supervised a total of 7 students that assisted our work in a variety of ways (field and/or lab work, data analyses, independent projects) on a number of projects going on in the lab.

In a typical year, GEMM Lab members would have undertaken quite a lot more travel, largely to attend conferences. Due to COVID-19, most conferences were either cancelled or held virtually. Leigh gave the plenary talk at the annual State of the Coast Conference, one of the favorite conferences of the GEMM Lab as it brings together scientists, stakeholders, managers, students, and the public to discuss Oregon-centric topics. Dawn gave an oral presentation at the International Marine Conservation Congress. The talk was titled “Wind, green water, and blue whales: Predictive models forecast blue whale distribution in an upwelling system to mitigate industrial impacts” as part of a symposium focused on evidence-based solutions for the management of large marine vertebrate species. Clara presented at the annual Research Advances in Fisheries, Wildlife & Ecology symposium hosted by the graduate student association in the Department of Fisheries & Wildlife. Clara’s talk, which was about her proposed PhD research, was titled “Drone footage reveals patterns of gray whale behavior across space, time, and the individual”.

While our travel may have been reduced this year, the lab certainly has had a prolific year of writing! The 19 new publications in 16 scientific journals include contributions from Leigh (6), Leila (5), Rachael (4), Solène (3), Clara (3), Dawn (2), and Ale (1). Scroll down to the end of the post to see the full list.

We are also very excited about a new addition to the lab. Rachel Kaplan, who is co-advised by Leigh and Dr. Kim Bernard in the College of Earth, Ocean, and Atmospheric Sciences, started her PhD at OSU in the fall. Rachel is one of this year’s recipients of the highly-competitive National Science Foundation’s Graduate Research Fellowship. Receiving the fellowship allowed Rachel to wrap up her job at the Bigelow Laboratory for Ocean Sciences in Maine and move to Oregon. The journey wasn’t easy (Rachel moved in the midst of the pandemic and during the height of the wildfires that raged across the U.S. West Coast) but she made it here safely! For her PhD, Rachel will try to understand how oceanographic factors and prey patches shape the distribution of whales in Oregon waters (with data collected through the OPAL project) to work towards solutions to the high rates of whale entanglements in fishing gear that have occurred on the West Coast since 2014. Welcome Rachel! 

While we persevered through tough times this year and have been lucky to celebrate many accomplishments, nothing prepared us for the shock that we all felt, and are still feeling deeply, about the loss of our fellow GEMM Lab graduate student Alexa Kownacki just over a month ago. Alexa’s optimism, generosity, and kindness were unparalleled, and the hole that she leaves in the lab and in our lives individually is gaping. The lab wrote a collaborative blog about Alexa a few weeks ago and we have created a website in her honor, where we encourage everyone to post photos, tributes or stories about Alexa. It has been so comforting to us to read people’s memories of Alexa that allow us to learn new things about her and remind us of our own memories. Alexa, we think of you every day and we miss you.

Alexa in her element

If you are reading this post, we would like to say thank you for all the support and interest in our work – we really appreciate it! Our blog’s viewership this year (a whopping 25,588 views!) has increased over a seven-fold since its creation in 2015 (3,462 views). We hope you will continue to join us on our journeys in 2021. Until then, stay safe, mask up & happy holidays from the GEMM Lab!

A GEMM Lab Happy Hour Zoom

Publications

Ajó, A. A. F., Hunt, K. E., Giese, A. C., Sironi, M., Uhart, M., Rowntree, V. J., Marón, C. F., Dillon, D., DiMartino, M., & Buck, C. L. (2020). Retrospective analysis of the lifetime endocrine response of southern right whale calves to gull wounding and harassment: A baleen hormone approach. General and Comparative Endocrinology, 296, 113536.

Albert, C., …, Orben, R. A., et al. (2020). Seasonal variation of mercury contamination in Arctic seabirds: a pan-arctic assessment. Science of the Total Environment, 750, 142201.

Barlow, D. R., Bernard, K. S., Escobar-Flores, P., Palacios, D. M., & Torres, L. G. (2020). Links in the trophic chain: modeling functional relationships between in situ oceanography, krill, and blue whale distribution under different oceanographic regimes. Marine Ecology Progress Series, 642, 207-225.

Baylis, A. M. M., Tierney, M., Orben, R. A., González de la Peña, D., & Brickle, P. (2020). Non-breeding movements of Gentoo penguins at the Falkland Islands. Ibis, doi:10.1111/ibi.12882.

Bird, C., & Bierlich, K.. (2020).  CollatriX: A GUI to collate MorphoMetriX outputs. Journal of Open Source Software, 5(51), 2328. doi:10.21105/joss10.21105/joss.02328.

Bird, C., Dawn, A. H., Dale, J., & Johnston, D. W. (2020). A Semi-Automated Method for Estimating Adélie Penguin Colony Abundance from a Fusion of Multispectral and Thermal Imagery Collected with Unoccupied Aircraft Systems. Remote Sensing, 12(22), 3692. doi:10.3390/rs12223692.

Chero, G., Pradel, R., Derville, S., Bonneville, C., Gimenez, O., & Garrigue, C. (2020). Reproductive capacity of an endangered and recovering population of humpback whales in the Southern Hemisphere. Marine Ecology Progress Series, 643, 219-227.

Derville, S., Torres, L. G., Zerbini, A. N., Oremus, M., & Garrigue, C. (2020). Horizontal and vertical movements of humpback whales inform the use of critical pelagic habitats in the western South Pacific. Scientific Reports, 10, 4871.

DiGiacomo, A. E., Bird, C., Pan, V. G., Dobroski, K., Atkins-Davis, C., Johnston, D. W., & Ridge, J. T.. (2020). Modeling Salt Marsh Vegetation Height Using Unoccupied Aircraft Systems and Structure from Motion. Remote Sensing, 12(14), 2333. doi:10.3390/rs12142333.

Garrigue, C., Derville, S., Bonneville, C., Baker, C. S., Cheeseman, T., Millet, L., Paton, D., & Steel, D. (2020). Searching for humpback whales in a historical whaling hotspot of the Coral Sea, South Pacific. Endangered Species Research, 42, 67-82.

Hauser-Davis, R. A., Monteiro, F., Chávez da Rocha, R. C., Lemos, L., Duarte Cardoso, M., & Siciliano, S. (2020). Titanium as a contaminant of emerging concern in the aquatic environment and the current knowledge gap regarding seabird contamination. Ornithologia, 11, 7-15.

Hindell, M. A., … Torres, L. G., et al. (2020). Tracking of marine predators to protect Southern Ocean ecosystems. Nature, 580(7801), 87-92.

Jones, K. A., Baylis, A. M. M., Orben, R. A., Ratcliffe, N., Votier, S. C., Newton, J., & Staniland, I. J. (2020). Stable isotope values in South American fur seal pup whiskers as proxies of year-round maternal foraging ecology. Marine Biology, 167(10), 1-11.

Kroeger, C. E., Crocker, D. E., Orben, R. A., Thompson, D. R., Torres, L. G., Sagar, P. M., Sztukowski, L. A., Andriese, T., Costa, D. P., & Shaffer, S. A. (2020). Similar foraging energetics of two sympatric albatrosses despite contrasting life histories and wind-mediated foraging strategies. Journal of Experimental Biology, 223, jeb228585.

Lemos, L. S., Olsen, A., Smith, A., Chandler, T. E., Larson, S., Hunt, K., & Torres, L. G. (2020). Assessment of fecal steroid and thyroid hormone metabolites in eastern North Pacific gray whales. Conservation Physiology, 8, coaa110.

Monteiro, F., Lemos, L. S., et al. (2020). Total and subcellular Ti distribution and detoxification processes in Pontoporia blainvillei and Steno bredanensis dolphins from southeastern Brazil. Marine Pollution Bulletin, 153, 110975.

Quinete, N., Hauser-Davis, R. A., Lemos, L. S., Moura, J. F., Siciliano, S., & Gardinali P. R. (2020). Occurrence and tissue distribution of organochlorinated compounds and polycyclic aromatic hydrocarbons in Magellanic penguins (Spheniscus magellanicus) from the southeastern coast of Brazil. Science of the Total Environment, 749, 141473.

Soledade Lemos, L., Burnett, J. D., Chandler, T. E., Sumich, J. L., & Torres, L. G. (2020). Intra- and inter-annual variation in gray whale body condition on a foraging ground. Ecosphere, 11(4), e03094.

Torres, L. G., Barlow, D. R., Chandler, T. E., & Burnett, J. D. (2020). Insight into the kinematics of blue whale surface foraging through drone observations and prey data. PeerJ, 8, e8906.

Summaries, highlights, and musings – our 2020 gray whale field seasons at a glance

By Lisa Hildebrand, MSc student, OSU Department of Fisheries & Wildlife, Marine Mammal Institute, Geospatial Ecology of Marine Megafauna Lab

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 represent the 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 1 shows 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.

Do gray whales count calories?

By Lisa Hildebrand, MSc student, OSU Department of Fisheries & Wildlife, Marine Mammal Institute, Geospatial Ecology of Marine Megafauna Lab

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.

What is a scientist?

By Noah Dolinajec, MSc student, Vrije Universiteit Brussel, GEMM Lab summer intern

There is something special about the Oregon Coast. It’s like nowhere else in the world. When Lisa told me that gray whales are understudied on our coastline, I secretly and selfishly thought to myself, “I hope it stays that way”. Then I would have a chance to be a pioneer one day too, studying something along this rugged coast full of life, death and everything in between, that no one has answered before. Of course, I only feel this way half of the time.

Yet, the more time I spend in Port Orford, the more I realize that our coastline truly is one of those last frontiers. A place where fundamental questions have yet to be explored, where the passing of seasons brings with it a violent change in conditions. From sunny summer days on the Port Orford beaches taking in the soft glistening of sunlight illuminating Redfish Rocks Marine Reserve, to cold, dark and stormy months with no end in sight and nothing but the sound of wind curving around the bends of your home and rain puttering against the windows.

Noah reading a book on the cliff site with a view of Mill Rocks in the background. Source: N. Dolinajec.

But no matter the season, no matter the conditions, the Oregon Coast harnesses something truly special, truly extraordinary. A cyclical diversity of life.

Since I was a kid, the Oregon Coast has inspired me. Not always to think about wildlife, in fact, mostly in other ways. To contemplate more primal philosophical questions. At 28 years old, it’s been a longer road than expected to get to this point, working with these amazing people, in this amazing place, on this amazing project. And the more time that passes, the more failures, missteps and dysfunctional experiences I absorb, the more that I learn about what really needs to change. In the world of course, but, mostly in science.

In the past few years, as I eek closer to 30, and I begin to look back on some of the adventures I have taken in my life, I take heavy note of where I am now, sitting on a kayak in Mill Rocks sampling for gray whale prey abundance and distribution, or atop the cliff, gazing out into the open ocean waiting patiently and graciously (at least trying to be) for a small poof of water spray from the beating surface of the sea. That little poof? It may not seem like much but it’s a sign of life. Of an age-old journey, one we know very little about. And here I am, a part of it, albeit a small one, but nevertheless, forever a part of that great journey.

A foggy view of Mill Rocks from the cliff (left) and a shot from the kayak (right). Source: N. Dolinajec.

And without losing sight of my job, sampling for zooplankton or tracking the whales as they move across the open water, I’ve found myself thinking about the depth of being involved in such an ancient process, and considering a very important question. One that doesn’t spend nearly enough time in the day-to-day conversation of an academic…

What exactly is a scientist? And how does one become a scientist?

The academic path to the sciences is exclusionary, beyond any reasonable level. It discriminates on gender, race, experience and age. Making the sciences, which are meant as a tool to better the world and make useful contributions to society and the future, feel inaccessible for so many people full of potential but without the right boxes ticked on a form.

How many beautiful ideas have been left to decay because of the ego that science has built for itself?

A sign that sits in the front window of the OSU Port Orford Field Station. Source: N. Dolinajec.

Don’t get me wrong, I love science, it has given me joy that other things in life cannot. It has shown me both the complexity of the world and the simplicity of how we view it. And I believe that science can still be the future. But in order for science to command our future, to guide us in the right direction, it cannot be a hierarchy of antiquated procedures any longer. We must open our arms, our minds and our resources to take chances on students, far and wide, that may lack traditional training but instead have other skills or experiences to offer science. Science needs an overhaul. Science needs diversity.

After all, change of perspective can be a profound driver of scientific results, can it not?

Here in Port Orford, in this bizarre year of 2020, we have the beginning, the makings if-you-will, of that very diversity that I am speaking of. The four of us, ‘The Theyodelers’ as we righteously call ourselves, each come from such drastically different places in life only to meet under the same roof for 6 weeks and miraculously not only survive together, but thrive together.

‘The Theyodelers’ after the 2020 (virtual) Port Orford Community Presentation, from left to right: Dr. Leigh Torres, Lisa Hildebrand, Liz Kelly, Mattea Holt Colberg, Noah Dolinajec, Tom Calvanese, Tom McCambridge (front). Source: L. Hildebrand.

And that, that essence of positivity that we have been able to build around one another this season, is exactly what I mean when I say that science needs an overhaul.

We do not all find our way to this moment, doing science in such an inspiring place, in the same way. Some of us are born with the innate ability to see the world through objective eyes, the kind of mind that makes great science happen from an early age. And others find our way to science after being enlightened by trials and travails, failures and mistakes, missed opportunities and missteps.

No matter the journey, we all ended up here. Watching these great gray giants on their journeys.

And it all comes full circle doesn’t it?

Each of our journeys, human or whale, can lead to the very same point despite beginning at very different places. And in that diversity of experience, of life, of age, of color, is where we find our brightest moments, our grandest ideas and our future, driven by science.

New experiences, new emotions, new skills

By Elizabeth Kelly, Pacific High School senior, GEMM Lab summer intern

Figure 1. Liz on the cliff. Source: E. Kelly.

The gray whale foraging ecology project with OSU’s GEMM Lab has been nothing short of a dream come true. Going into this internship, I was just a high schooler who had taken zoology my previous school year. With my lack of a formal education in marine biology, let alone gray whales, I was a little daunted at the thought of going to a university field station with college students and actual biologists. When I applied for this internship, I didn’t think I was even going to be accepted for the internship, but I applied with high hopes and a lot of excitement. When I was officially accepted, I wanted to start immediately. 

Despite my concerns of the steep learning curves I knew I would have to overcome, I was ready to jump right into the internship. The other interns live at the field station since they do not live locally, but I drive to the field station every morning because I live about 20 minutes away. However, this situation has never made me feel like an outsider. I spend a lot of my time at the field station and it would be hard to not get comfortable there immediately. I don’t feel sad that somebody is cooking some sort of delicious meal every night because even though I don’t live at the station, I sometimes stay for dinners. When I’m there for whatever reason, whether it be while working or eating and hanging out after a day of working or during breaks, I never feel out of my depth socially or even academically even though I am clearly younger and less experienced. The environment and team here, which is made up of scholarly individuals with lots of personality and character, is never judgemental or patronizing; rather it is inviting and the graduate student intern, Noah, and my team leader, Lisa, give off a feeling of mentorship. This has made my internship fun and given me far more of an interest and intent towards pursuing Wildlife Sciences after high school. 

Figure 2. A photo taken by Liz today on the cliff as a whale traveled from Tichenor Cove to Mill Rocks. Source: GEMM Lab.

While there have been tedious parts of the internship with a steep learning curve, including asking many questions about whales, and learning to use different programs, tools and methods, it all pays off and comes in handy when the whole focus of the work comes through town – the famous gray whales. During this field season we have been having low whale sightings for the first 4 weeks (but our sightings are slowly picking up over the last couple days), so the waiting for the grand appearance of a whale can feel eternal. Though, when the red curtains reveal a blow out in the distance headed our way, the feeling of boredom when staring at the ocean is completely forgotten. Suddenly, everyone jumps to action – the theodolite’s position needs to be adjusted as we try to pinpoint where the whale will surface next after its dive. 

Figure 3. A zoomed-in photo from the kayak of a gray whale headstanding (a feeding behavior) in Tichenor Cove. Source: E. Kelly.

Recently we have been collecting larger samples of zooplankton when sampling from our research kayak, and the whales have been coming in larger numbers too. Every time I see a whale while I am out on the kayak I am crippled with excitement and adrenaline. There is absolutely nothing like seeing these majestic mammals out and about in their day-to-day lives. I love when I get to see them forage, blow, shark, and even do headstands in the water. When we see them forage in a spot that is not one of our regular zooplankton sampling stations we do some adaptive sampling (sampling at spots where we see whales actively feeding), and so far the whales haven’t lied to me about where the zooplankton is. I’m very curious as to how the whales know where the higher concentrations of zooplankton are, even in low visibility (we have had plenty of that this year too). Nevertheless, they know and aren’t shy about getting what they want. 

The only downfall of this internship is that it ends soon. I have thoroughly enjoyed my time with my team and at the field station. This in-the-field experience is one of a kind. Even though I didn’t think I was going to receive this internship, I really wanted it and now that I have had it and am finishing up with it, I am so grateful for the knowledge and experiences I have gained from it and look forward to the opportunities it will further grant me.

Questions that drive my research curiosity

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.

Introducing the Theyodelers – the Port Orford Gray Whale Foraging Ecology Team of 2020

By Lisa Hildebrand, MSc student, OSU Department of Fisheries & Wildlife, Marine Mammal Institute, Geospatial Ecology of Marine Megafauna Lab

Yodel-Ay-Ee-Ooooo! Hello from the Theyodelers, this year’s Port Orford gray whale foraging ecology field team. In case you were wondering, no, we aren’t hobby yodelers and we don’t plan on becoming them. The team name this year actually has to be attributed to a parent of one of my interns. Shout out to Scott Holt who during the first week of the field season asked his daughter Mattea (our OSU undergraduate intern) whether using a theodolite (the instrument we use to track gray whales from our cliff site) is anything like yodeling. The name was an immediate hit with the team and so the team name discussion was closed fairly early on in the season. Now that I have explained our slightly unconventional team name, let me tell you a little about this year’s team and what has been going on down here on the Oregon south coast so far.

As you can tell from the byline, I (Lisa) am back as the project’s team lead in this, the 6th year of the Port Orford gray whale research and internship project. Going into this year’s field season with two years of experience under my belt has made me feel more confident and comfortable with diving straight back into our fine-scale research with a new team of interns. Yet, I am beginning to realize that no matter how much experience I have, there will always be unforeseeable curve balls thrown at me that I can’t anticipate no matter how prepared or experienced I am. However, my knowledge and experience now certainly inform how I tackle these curve balls and hopefully allow my problem-solving to be better and quicker. I am so thrilled that Leigh and I were able to get the field season approved here in Port Orford despite the ongoing pandemic. There were many steps we had to take and protocols to write and get approved, but it was worth the work. It certainly is strange living in a place that is meant to be your home for six weeks but having to wear a face covering everywhere except your own bedroom. However, mask wearing, frequent hand washing, and disinfecting is a very small price to pay to avoid having a lapse in our gray whale data collected here in Port Orford (and minimize transmission). Doing field research amidst COVID has certainly been a big curve ball this year but, so far, I have been able to handle these added challenges pretty well, especially with a lot of help from my team. Speaking of which, time to introduce the other Theyodelers…

Figure 1. Noah watching and waiting for whales on the cliff. When we are outside in the wind and are able to maintain a minimum 6-ft distance, we are able to remove our face coverings. Source: T. McCambridge.

First up, we have Noah Dolinajec. Noah is a fellow graduate student who is currently doing a Master’s in Marine & Lacustrine Science and Management at the Vrije Universiteit Brussel in Brussels, Belgium. While he is attending graduate school in Belgium, Noah is not actually from this European country. In fact, he is a Portlandian! As an Oregonian with a passion for the marine environment, Noah is no stranger to the Oregon coast and has spent quite some time exploring it in the past. Some other things about Noah: before going to college he played semi-professional ice hockey, he is a bit of a birder, and he likes to cook (he and I have been tag-teaming the team cooking this year). 

Figure 2. Mattea outside the field station holding local fisher-pup Jim. Source: L. Hildebrand.

Next, we have Mattea Holt Colberg. As I mentioned before, Mattea is the team’s OSU undergraduate intern this year. By participating in a running-start program at her high school where she took two years of college classes, Mattea entered OSU as a junior at just 18 years old! However, she has decided to somewhat extend her undergraduate career at OSU by completing a dual major in Biology and Music. She plays the piano and the violin (which she brought to Port Orford, but we have yet to be serenaded by her). Mattea has previously conducted field research on killer whales in the Salish Sea and I can tell that she is hoping for killer whales to show up in Port Orford (while not entirely ludicrous, the chance of this happening is probably very, very slim). 

Figure 3. Liz in the bow of the kayak in Tichenor Cove. Source: L. Hildebrand.

Last but certainly not least, is Liz Kelly, our Pacific High School intern from Port Orford. Liz has lived in several different states across the country (I’m talking Kentucky to Florida) and so I am really excited that she currently lives here in Oregon because she has been an absolute joy to have on the team so far. Liz brings a lot of energy and humor to the team, which we have certainly needed whenever those curve balls come flying. Besides her positivity, Liz brings a lot of determination and perseverance and seeing her work through tough situations here already has made me very proud. I really hope this internship provides Liz with the life, STEM, and communication skills she needs to help her succeed in pursuing her goals of doing wildlife research after college. As you may have read in my last blog, our previous high school interns have had successes in being admitted to various colleges to follow their goals, and I feel confident that Liz will be no different. When she is not here at the field station, she can probably be found taking care of and riding one of her four horses (Millie, Maricja, Miera, and Jeanie). 

Now that I have introduced the 2020 field team, here is a short play-by-play of what we have been seeing, or perhaps more aptly, not seeing. Our whale sighting numbers have been pretty low so far and when we do see them, they seem to be foraging a little further away from our study site than I am used to seeing in past years. However, this shift in behavior is not entirely surprising to me since our zooplankton net has been coming up pretty empty at our sampling stations. While there are mysids and amphipods scattered here and there, their numbers are in the low 10s when we do our zooplankton ID lab work in the afternoons. These low counts are also reflected by the low densities I am anecdotally seeing on our GoPro drops (Fig 4).

Figure 4. Comparison of zooplankton density from our GoPro videos. Both images were taken at the same sampling station (Tichenor Cove 8), however the image on the left that contains a lot of little critters is from 2018, whereas the image on the right is from last week. This year our drops have been looking more like the image on the right, though typically with even fewer zooplankton.

While I am not entirely certain why we are seeing this low prey abundance, I do have some hypotheses. The most likely reason is that this year we experienced some delayed upwelling on our coast. Dawn wrote a great blog about upwelling and wind a few weeks ago and I suggest checking it out to better understand what upwelling is and how it can affect whales (and the whole ecosystem). Typically, we see our peak upwelling occur here in Oregon in May-June. However, if you look at Figure 5 you will see that both the indices remained low at that time this year, whereas in previous years, they were already increasing by May/June.

Figure 5. 10 year time series of the Coastal Upwelling Transport Index (CUTI; top plot) and Biologically Effective Upwelling Transport Index (BEUTI; bottom plot) at 44ºN. CUTI represents the amount of upwelling (positive numbers) or downwelling (negative numbers) while BEUTI estimates the amount of nitrate (i.e. nutrients) upwelled (positive numbers) and downwelled (negative numbers). The light-colored lines represent the CUTI and BEUTI at that point in time while the dark, bold lines represent the long-term average.

A delayed upwelling means that there was likely less nutrients in the water to support little critters like zooplankton to start reproducing and increasing their abundances. Simply put, it means our coastal waters appear to be less productive than they usually are at this time of the year. If there is not much prey around (as we have been finding in our two study sites – Mill Rocks and Tichenor Cove), then it makes sense to me why gray whales are not hanging around since there is not much to feed on. Fortunately, the tail of the trend line in Figure 5 is angling upward, which means that the upwelling finally started in June so hopefully the nutrients, zooplankton and whales will follow soon too. In fact, since I wrote the draft of this blog at the end of last week, we have actually seen an increase in the numbers of mysids in our zooplankton net and on our GoPro videos.

We are almost halfway done with the field season already and I cannot believe how quickly it goes by! During the first two weeks we were busy getting familiar with all of our gear and completing First Aid/CPR and kayak paddle & rescue courses. This week the team started the real data collection. We have had some hiccups (we lost our GoPro stick and our backup GoPro stick, but thankfully have already recovered one of them) but overall, we are off to a pretty good start. Now we just need the upwelling to really kick in, for there to be thick layers of mysids, and for the whales to come in close. Over the next three weeks, you will be hearing from Noah, Mattea and Liz as they share their experiences and viewpoints with all of you!

The impact of science

By Lisa Hildebrand, MSc student, OSU Department of Fisheries & Wildlife, Marine Mammal Institute, Geospatial Ecology of Marine Megafauna Lab

What do I mean by impact? There are different ways to measure the impact of science and I bet that the readers of this blog had different ideas pop into their heads when they read the title. My guess is that most ideas were related to the impact factor (IF) of a journal, which acts as a measure of a journal’s impact within its discipline and allows journals to be compared. Recent GEMM Lab graduate and newly minted Dr. Leila Lemos wrote a blog about this topic and I suggest reading it for more detail. In a nutshell though, the higher the IF, the more prestigious and impactful the journal. It is unsurprising that scientists found a way to measure our impact on the broader scientific community quantitatively.

However, IFs are not the impact I was referring to in my title. The impact I am talking about is arguably much harder to measure because you can’t easily put a number on it. I am talking about the impact we have on communities and individuals through outreach and engagement. The GEMM Lab’s Port Orford gray whale ecology project, which I lead, is going into its 6th consecutive year of summer field work this year. Outreach and engagement are two core components of the project that I have become very invested in since I started in 2018. And so, since we are only one week away from the field season commencing (yes, somehow it’s mid-July already…), for this week’s blog I have decided to reflect on what scientific outreach and engagement is, how we have tried to do both in Port Orford, and some of the associated highs and lows.

2018 team member Dylan presenting at the Port Orford community presentation. Source: T. Calvanese.

I think almost everyone in the scientific community would agree that outreach and engagement are important and that we should strive to interact frequently with the public to be transparent and build public trust, as well as to enable mutual learning. However, in my opinion, most scientists rarely put in the work needed to actually reach out to, and engage with, the community. Outreach and engagement have become buzzwords that are often thrown around, and with some hand-waving, can create the illusion that scientists are doing solid outreach and engagement work. For some, the words are probably even used interchangeably, which isn’t correct as they mean two different things.

Outreach and engagement should be thought of as occurring on two different ends of a spectrum. Outreach occurs in a one-way direction. Examples of outreach are public seminars delivered by a scientist (like Hatfield’s monthly Science on Tap) or fairs where the public is invited to come and talk to different scientific entities at their respective booths (like Hatfield’s annual Marine Science Day). Outreach is a way for scientists to disseminate their research to the public and often do not warrant the umbrella term engagement, as these “conversations” are not two-way. Engagement is collaborative and refers to intentional interactions where both sides (public and scientist) share and receive. It goes beyond a scientist telling the public about what they have been doing, but also requires the scientist to listen, absorb, and implement what the views from the ‘other side’ are.

2015 team tracking a whale on Graveyard Point above the port of Port Orford. Source: F. Sullivan.

Now that I have (hopefully) clarified the distinction between the two terms, I am going to shift the focus to specifically talk about the Port Orford project. Before I do, I would like to emphasize that I do not think our outreach and engagement is the be-all and end-all. There is definitely room for improvement and growth, but I do believe that we actively work hard to do both and to center these aspects within the project, rather than doing it as an afterthought to tick a box. 

In talking about outreach and engagement, I have been using the words ‘public’ and ‘community’. I think these words conjure an image of a big group of people, an entire town, county, state or even nation. While this can be the case, it can also refer to smaller groups of people, even individuals. The outreach we conduct for the Port Orford project certainly occurs at the town-level. At the end of every field season, we give a community presentation where the field team and Leigh present new findings and give a recount of the field season. In the past, various teams have also given talks at the Humbug Mountain Campground and at Redfish Rocks Community Team events. These events, especially the community presentation, have been packed to the brim every year, which shows the community’s interest for the gray whales and our research. In fact, Tom Calvanese, the OSU Port Orford Field Station manager, has shared with me that now in early summer, Port Orford residents ask him when the ‘whale team’ is returning. I believe that our project has perhaps shifted the perception the local community has of scientists a little bit. Although in our first year or two of the project we may have been viewed as nosy outsiders, I feel that now we are almost honorary members within the community. 

A packed room at the 2017 Port Orford community presentation. Photo: GEMM Lab.

Our outreach is not just isolated to one or two public talks per field season though. We have been close collaborators with South Coast Tours (SCT), an adventure tour company headed by Dave Lacey, since the start of the project. During the summer, SCT has almost daily kayak and fishing tours (this year, boat tours too!) out of Port Orford. The paddle routes of SCT and our kayak team will typically intersect in Tichenor’s Cove around mid-morning. When this happens, we form a little kayak fleet with the tour and research kayaks and our kayak team gives a short, informal talk about our research. We often pass around samples of zooplankton we just collected and answer questions that many of the paddlers have. These casual interactions are a highlight to the guests on SCT’s tours (Dave’s words, not mine) and they also provide an opportunity for the project’s interns to practice their science communication skills in a ‘low-stakes’ setting. 

The nature of our engagement is more at the individual-level. Since the project’s conception in 2015, the team has been composed of some combination  of 4-5 students, be it high school, undergraduate or graduate students. Aside from Florence Sullivan and myself as the GEMM Lab graduate student project leads, in total, we have had 16 students participate in the program, of which 4 were high school students (two from Port Orford’s Pacific High School and two from Astoria High School), 11 OSU and Lawrence University undergraduates, and 1 Duke University graduate student. This year we will be adding 3 more to the total tally (1 Pacific High School student, 1 OSU undergrad, and 1 graduate student from the Vrije Universiteit Brussel in Belgium). I am the first to admit that our yearly (and total) numbers of ‘impacted’ students is small. Limitations of funding and also general logistics of coordinating a large group of interns to participate in field work prevent us from having a larger cohort participate in the field season every summer. However, the impact on each of these students is huge. 

The 2019 team with Dave Lacey who instructed our kayak paddle & safety course. Photo: L. Hildebrand.

If I had to pick one word to describe the 6-week Port Orford field season, it would be ‘intense’. The word is perfect because it can simultaneously describe something positive and negative, and the Port Orford field season definitely has elements of both. Both as a team and as individuals we experience incredible high points (an example being last year when we saw Port Orford’s favorite whale ‘Buttons’ breach multiple times on several different days), but we also have pretty low points (I’m thinking of a day in 2018 when two of my interns tried incredibly hard to get our GoPro stick dislodged from a rocky crevice for over 1-hour before radioing me to tell me they couldn’t retrieve it). These highs and lows occur on top of the team’s slowly depleting levels of energy as the field season goes on; with every day we get up at 5:30 am and we get a little more exhausted. The work requires a lot of brain power, a lot of muscle, and a lot of teamwork. Like I said, it’s intense and that’s coming from someone who had several years of marine mammal field work experience before running this project for the first time in 2018. The majority of the interns who have participated in our project have had no marine mammal field experience, some have had no field experience at all. It’s double, if not triple, intense for the interns!

I ask a lot of my interns. I am aware of that. It has been a steep learning curve for me since I took on the project in 2018. I’ve had to adjust my expectations and remember not to measure the performance of my interns against my own. I can always give 110% during the field season, even when I’m exhausted, because the stakes are high for me. After all, the data that is being collected feeds straight into my thesis. However, it took me a while to realize that the stakes, and therefore the motivation, aren’t the same for my interns as they are for me. And so, expecting them to perform at the same level I am, is unfair. I believe I have grown a lot since running that first field season. I have taken the feedback from interns to heart and tried to make adjustments accordingly. While those adjustments were hard because it ultimately meant making compromises that affected the amount of data collected, I recognize and respect the need to make those adjustments. I am incredibly grateful to all of the interns, including the ones that participated before my leadership of the project,  who really gave it their all to collect the data that I now get to dig into and draw conclusions from.

2016 interns Kelli and Catherine paddling to a kayak sampling station. Photo: F. Sullivan.

But, as I said before, engagement is not one-sided, and I am not the only one who benefits from having interns participate in the project. The interns themselves learn a wealth of skills that are valuable for the future. Some of these skills are very STEM (Science, Technology, Engineering & Mathematics) specific (e.g. identifying zooplankton with a microscope, tracking whales with a theodolite), but a lot of them are transferrable to non-STEM futures (e.g. attention to detail and concentration required for identifying zooplankton, team work, effective communication). Our reach may be small with this project but the impact that participating in our internship has on each intern is a big one. Three of our four high school interns have gone on to start college. One plans to major in Marine Studies (in part a result of participating in this internship) while another decided to go to college to study Biology because of this internship. Several of the undergraduate students that participated in the 2015, 2016, 2017 & 2018 field seasons have gone on to start Master’s degrees at graduate schools around the country (3 of which have already graduated from their programs). A 2015 intern now teaches middle school in Washington and a 2016 intern is working with Oceans Initiative on their southern resident killer whale project this summer. Leigh, Florence and I have written many letters of recommendations for our interns, and these letters were not written out of duty, but out of conviction.

I love working closely with students and watching them grow. For the last two years, my proudest moment has always been watching my interns present our research at the annual community presentation we give at the end of the field season in Port Orford. No matter the amount of lows and struggles I experienced throughout the season, I watch my interns and my face almost hurts because of the huge smile on my face. The interns truly undergo a transformation where at the start of the season they are shy or feel inadequate and awkward when talking to the public about gray whales and the methods we employ to study them. But on that final day, there is so much confidence and eloquence with which the interns talk about their internship, that they are oftentimes even comfortable enough to crack jokes and share personal stories with the audience. As I said before, engagement of this nature is hard to measure and put a number on. Our statistic (engaging with 16 students) makes it sound like a small impact, but when you dig into what these engagements have meant for each student, the impact is enormous.

All of the past PO gray whale ecology teams, from left to right: 2015 (Sarah, Florence, Cricket, Justin), 2016 (Florence, Kelli, Catherine, Cathryn), 2017 (Nathan, Quince, Florence, Morgan), 2018 (Haley, Robyn, Hayleigh, Dylan, Lisa), and 2019 (Anthony, Donovan, Lisa, Mia). Bottom left: Florence and Leigh; bottom right: Lisa and Leigh.

I treasure my 6 weeks in Port Orford. Even though they are intense and there are new challenges every year, they bring me a lot of happiness. And it’s only in part because I get to see gray whales and kayak on an (almost) daily basis. A large part is because of the bonds I have formed and continue to cultivate with Port Orford locals, the leaps and bounds I know the interns will make, and the fact that the gray whales, completely unknowingly, bring together a small group of students and a community every year. 

If you feel like taking a trip down memory lane, below are the links of the blogs written by previous PO interns:

2015: Cricket, Justin, Sarah

2016: Catherine, Kelli, Cathryn

2017: Morgan, Nathan, Quince

2018: Haley, Dylan, Hayleigh, Robyn

2019: Mia, Donovan, Anthony

Feasts of junk food or morsels of fine dining: is prey quality or quantity more important to marine predators?

By Lisa Hildebrand, MSc student, OSU Department of Fisheries & Wildlife, Marine Mammal Institute, Geospatial Ecology of Marine Megafauna Lab

Knowing what and how much prey a predator feeds on are key components to better understanding and conserving that predator. Prey abundance and availability are frequently predictors for marine predator reproductive success and population dynamics. It is the reason why the GEMM Lab makes a concerted effort to not only track our main taxa of interest (marine mammals) but to simultaneously measure their prey. However, over the last decade or two, there has been increased recognition that prey quality is also highly important in understanding a predator’s ecology (Spitz et al. 2012). Optimal foraging theory is a widely accepted framework that posits that predators should attempt to maximize energy gained and minimize energy spent during a foraging event (Charnov 1976, Krebs 1978, Pyke 1984). Thus, knowledge of how valuable a prey item is in terms of its energetic content is an important part of the equation when applying optimal foraging theory to a predator of interest.

Ideally, the prey species with the highest energetic value would also be the easiest, most ubiquitous and least energetically expensive prey item to capture and consume, such that a predator truly could expend very little energy to get very high energetic rewards. However, it rarely is this straightforward. The caloric content of several marine prey species has been shown to increase with increasing size (e.g. Benoit-Bird 2004; Fig. 1), both length and weight. Yet, increasing size often also means increased mobility and, as a result, ability to evade and escape predation. Furthermore, increasing size also inherently means decreasing abundances – there will always be billions more krill in the ocean than whales based solely on cost of reproduction. Therefore, just based on sheer numbers, there are fewer big prey items, which increases the time between, and decreases the likelihood of, a predator encountering big prey items. So, there are clear trade-offs here. It may take longer to locate and capture a high value prey item, which costs more energy to capture, but the payout could potentially be much bigger. However, if a predator gambles too much, then their net energy expenditure to obtain high value prey may be higher than the net energy gained. Instead, it may be worth pursuing smaller prey items with lower energetic values, where discovery and capture success are higher and more frequent. However, in this case, many, many more pursuits are likely needed, thus costing more energy to meet daily energetic demands. 

Figure 1. Increasing caloric content with increasing length (a) and wet weight (b). Figures and caption reproduced from Benoit-Bird 2004.

Is your head spinning as much as mine? Let me try and simplify this complex web of interactions with a tangible example. Bowen et al. (2002) investigated foraging of harbor seals in Nova Scotia to assess prey profitability of different species. By attaching camera systems to the backs of 39 adult male harbor seals, the authors identified sand lance and flounder to be the most targeted prey species. However, there were significant differences in pursuit/handling cost per prey type (kJ/min) with sand lance only requiring 14.8 ± 2.7, whereas flounder required significantly more at 30.3 ± 7.9. Therefore, based solely on energy required to capture prey, the sand lance would seem to be the better option. In fact, to a certain degree, this hypothesis is actually true when we compare the energetic content of the two prey types. Sand lance have a higher energetic value at lengths of 10 and 15 cm (53.6 and 95.8 kJ, respectively) compared to flounder (22.6 and 88.6 kJ, respectively). So, the net gain of a harbor seal foraging on a 15 cm sand lance (assuming that it only takes 1 minute to catch the fish – this is more for explanatory purposes as it likely takes much longer for a harbor seal to capture a fish) would be 81 kJ. This gain is larger than that of a 15 cm flounder (58.3 kJ). However, once we compare these fish at 20 and 25 cm lengths, the flounder actually becomes the more beneficial prey item at 232.6 and 492.3 kJ, respectively, over the sand lance (158.1 and 233.8 kJ). Now, assuming once again that it only takes 1 minute to catch the fish, the harbor seal enjoys a net energetic gain of a whopping 462 kJ when capturing a 25 cm flounder compared to 219 kJ for a sand lance of the same size – that makes the flounder more than twice as profitable!

The Bowen et al. study is an excellent demonstration of the importance of considering the quality of prey items when studying the ecology of marine predators. However, the authors did not assess the relative availability of sand lance and flounder. Ideally, foraging ecology studies aimed at understanding prey choice would try to address both important prey metrics – quality and quantity. This goal is the exact aim of my second Master’s thesis chapter where I am investigating whether prey quality (determined through community composition and caloric content) or prey quantity (measured as relative density) is more important in driving fine-scale gray whale foraging behavior in Port Orford, Oregon (Fig. 2). This question can be simplified by asking does it matter more what prey is in an area, or how much prey there is in an area? Or we can relate it back to the title of this post by asking whether individual gray whales would rather attend a cheap all-you-can-eat buffet or an expensive fine-dining restaurant. I am unfortunately not quite done with my analyses yet (but I’m getting closer!) and therefore am not ready to answer these questions. However, I have done extensive research on this topic and therefore am in a position to briefly mention a few other studies that have investigated these questions for other marine predators. 

Figure 2. A question of what or how much. Left image: example of the screenshots we take to estimate relative prey density in Port Orford. Right images: two examples of the main prey species we find (top: mysid shrimp Neomysis rayii with a full brood pouch; bottom: amphipod Polycheria osborni).

Ludynia et al. (2010) explored reasons why African penguin (Spehniscus demersus) numbers have declined in Namibia. They found that after the collapse of pelagic fish stocks in the 1970s (including the principal penguin prey item, sardine), African penguins switched to feeding on bearded goby, which are considered a low-energy prey species. Bearded goby are relatively abundant along Namibia’s southern coast and as such, limited prey availability is not the reason for declining African penguin numbers. Therefore, the authors concluded that the low quality of bearded goby (compared to sardine) appears to be the reason for declining population trends  of the penguins. This study demonstrates that African penguins do better when eating at a fine-dining restaurant, rather than loading up a whole plate of junk food. 

Grémillet et al. (2004) studied the foraging effort and number of successful prey captures per foraging trip (yield) of great cormorants (Phalacrocorax carbo) in Greenland in relation to prey abundance and quality within their foraging areas. The authors radio-tracked 11 great cormorants during a total of 163 foraging trips to estimate foraging effort and yield. The study found that contrary to the authors’ hypothesis, great cormorants foraged in areas of low prey abundance where the average caloric value was also relatively low. Therefore, in this example, it would seem that the predator of interest prioritizes neither high quality nor quantity when foraging.

Haug et al. (2002) investigated the variations in minke whale (Balaenoptera acutorostrata) diet and body condition in response to ecosystem changes in the Barents Sea. The main prey item of minke whales in the Barents Sea is immature herring. However, when recruitment failure and subsequent weak cohorts leads to reduced availability of immature herring, minke whales switched their diet to other prey items such as krill, capelin, and sometimes other gadoid fish species. The authors found a correlation between body condition of minke whales and immature herring abundances, such that minke whales displayed a poor body condition during low immature herring abundances. However, in the years of low immature herring abundance, abundances of krill and capelin were not low. Therefore, similar to the Ludynia et al. (2010) study, it seems that minke whales in the Barents Sea also do better in years when the prey type of highest caloric value is the most abundant. However, decreases in high quality prey has not led to population declines in minke whales in the Barents Sea, indicating that they likely take advantage of high quantities of low quality prey, unlike the African penguins.

Clearly, the answer as to whether marine predators prefer quality over quantity is not simple and constant. Rather, prey preference varies based on predator needs and ecology, falling anywhere on a broad spectrum from low to high prey quality and low to high prey quantity (Fig. 3). To a certain extent, it probably also is not solely predator choice that determines what they eat but many other factors, such as climate, disturbance, and health. As a result, these preferences and choices will likely be fluid, rather than fixed. While I anticipate that individual gray whales will be flexible foragers, I do hypothesize that when there is a prey patch of a higher energetic value in the area, whales will preferentially consume these patches over areas where there is less energetically rich prey, even if it is more abundant. 

Figure 3. A spectrum of prey quantity and quality. Giant cormorants forage on low prey quality & quantity (Grémillet et al. 2004). African penguin populations are declining despite high abundances of low quality prey, suggesting that high prey quality is important for their survival (Ludynia et al. 2010). Body condition of Barents Sea minke whales decreases when high quality prey is less abundant, however their populations have not declined, suggesting they instead exploit high abundances of low quality prey (Haug et al. 2002). What will the gray whales do?

Literature cited

Benoit-Bird, K. J. 2004. Prey caloric value and predator energy needs: foraging predictions for wild spinner dolphins. Marine Biology 145:435-444.

Bowen, W. D., D. Tuley, D. J. Boness, B. M. Bulheier, and G. J. Marshall. 2002. Prey-dependent foraging tactics and prey profitability in a marine mammal. Marine Ecology Progress Series 244:235-245.

Charnov, E. L. 1976. Optimal foraging, the marginal value theorem. Theoretical Population Biology 9(2):129-136.

Grémillet D., G. Kuntz, F. Delbart, M. Mellet, A. Kato, J-P. Robin, P-E. Chaillon, J-P. Gendner, S-H. Lorentsen, and Y. Le Maho. 2004. Linking the foraging performance of a marine predator to local prey abundance. Functional Ecology 18(6):793-801.

Haug, T., U. Lindstrøm, and K. T. Nilssen. 2002. Variations in minke whale (Balaenoptera acutorostrata) diet and body condition in response to ecosystem changes in the Barents Sea. Sarsia 87(6):409-422. 

Krebs, J. R. 1978. Optimal foraging: decision rules for predators. Behvaioral Ecology: An Evolutionary Approach, eds. Krebs, J. R., and N. B. Davies. Oxford: Blackwell. 

Ludynia, J., J-P. Roux, R. Jones, J. Kemper, and L. G. Underhill. 2010. Surviving off junk: low-energy prey dominates  the diet of African penguins Spheniscus demersus at Mercury Island, Namibia, between 1996 and 2009. African Journal of Marine Science 32(3):563-572.

Pyke, G. H. 1984. Optimal foraging theory: a critical review. Annual Reviews of Ecology and Systematics 15:523-575.

Spitz, J., A. W. Trites, V. Becquet, A. Brind’Amour, Y. Cherel, R. Galois, and V. Ridoux. 2012. Cost of living dictates what whales, dolphins and porpoises eat: the importance of prey quality on predator foraging strategies. PLoS ONE 7(11):e50096.

Young, J. K., B. A. Black, J. T. Clarke, S. V. Schonberg, and K. H. Dunton. 2017. Abundance, biomass and caloric content of Chukchi Sea bivalves and association with Pacific walrus (Odobenus rosmarus divergens) relative density and distribution in the northeastern Chukchi Sea. Deep-Sea Research Part II 144:125-141.

You can’t build a pyramid without the base: diving into the foundations of behavioral ecology to understand cetacean foraging

By Lisa Hildebrand, MSc student, OSU Department of Fisheries & Wildlife, Marine Mammal Institute, Geospatial Ecology of Marine Megafauna Lab

The last two months have been challenging for everyone across the world. While I have also experienced lows and disappointments during this time, I always try to see the positives and to appreciate the good things every day, even if they are small. One thing that I have been extremely grateful and excited about every week is when the clock strikes 9:58 am every Thursday. At that time, I click a Zoom link and after a few seconds of waiting, I am greeted by the smiling faces of the GEMM Lab. This spring term, our Principal Investigator Dr. Leigh Torres is teaching a reading and conference class entitled ‘Cetacean Behavioral Ecology’. Every week there are 2-3 readings (a mix of book chapters and scientific papers) focused on a particular aspect of behavioral ecology in cetaceans. During the first week we took a deep dive into the foundations of behavioral ecology (much of which is terrestrial-based) and we have now transitioned into applying the theories to more cetacean-centric literature, with a different branch of behavior and ecology addressed each week.

Leigh dedicated four weeks of the class to discussing foraging behavior, which is particularly relevant (and exciting) to me since my Master’s thesis focuses on the fine-scale foraging ecology of gray whales. Trying to understand the foraging behavior of cetaceans is not an easy feat since there are so many variables that influence the decisions made by an individual on where and when to forage, and what to forage on. While we can attempt to measure these variables (e.g., prey, environment, disturbance, competition, an individual’s health), it is almost impossible to quantify all of them at the same time while also tracking the behavior of the individual of interest. Time, money, and unworkable weather conditions are the typical culprits of making such work difficult. However, on top of these barriers is the added complication of scale. We still know so little about the scales at which cetaceans operate on, or, more importantly, the scales at which the aforementioned variables have an effect on and drive the behavior of cetaceans. For instance, does it matter if a predator is 10 km away, or just when it is 1 km away? Is a whale able to sense a patch of prey 100 m away, or just 10 m away? The same questions can be asked in terms of temporal scale too.

What is that gray whale doing in the kelp? Source: F. Sullivan.

As such, cetacean field work will always involve some compromise in data collection between these factors. A project might address cetacean movements across large swaths of the ocean (e.g., the entire U.S. west coast) to locate foraging hotspots, but it would be logistically complicated to simultaneously collect data on prey distribution and abundance, disturbance and competitors across this same scale at the same time. Alternatively, a project could focus on a small, fixed area, making simultaneous measurements of multiple variables more feasible, but this means that only individuals using the study area are studied. My field work in Port Orford falls into the latter category. The project is unique in that we have high-resolution data on prey (zooplankton) and predators (gray whales), and that these datasets have high spatial and temporal overlap (collected at nearly the same time and place). However, once a whale leaves the study area, I do not know where it goes and what it does once it leaves. As I said, it is a game of compromises and trade-offs.

Ironically, the species and systems that we study also live a life of compromises and trade-offs. In one of this week’s readings, Mridula Srinivasan very eloquently starts her chapter entitled ‘Predator/Prey Decisions and the Ecology of Fear’ in Bernd Würsig’s ‘Ethology and Behavioral Ecology of Odontocetes’ with the following two sentences: “Animal behaviors are governed by the intrinsic need to survive and reproduce. Even when sophisticated predators and prey are involved, these tenets of behavioral ecology hold.”. Every day, animals must walk the tightrope of finding and consuming enough food to survive and ensure a level of fitness required to reproduce, while concurrently making sure that they do not fall prey to a predator themselves. Krebs & Davies (2012) very ingeniously use the idea of economic analysis of costs and benefits to understand foraging behavior (but also behavior in general). While foraging, individuals not only have to assess potential risk (Fig. 1) but also decide whether a certain prey patch or item is profitable enough to invest energy into obtaining it (Fig. 2).

Leigh’s class has been great, not only to learn about foundational theories but to then also apply them to each of our study species and systems. It has been exciting to construct hypotheses based on the readings and then dissect them as a group. As an example, Sih’s 1984 paper on the behavioral response race of predators and prey prompted a discussion on responses of predators and prey to one another and how this affects their spatial distributions. Sih posits that since predators target areas with high prey densities, and prey will therefore avoid areas that predators frequent, their responses are in conflict with one another. Resultantly, there will be different outcomes depending on whichever response dominates. If the predator’s response dominates (i.e. predators are able to seek out areas of high prey density before prey can respond), then predators and prey will have positively correlated spatial distributions. However, if the prey responses dominate, then the spatial distributions of the two should be negatively correlated, as predators will essentially always be ‘one step behind’ the prey. Movement is most often the determinant factor to describe the strength of these relationships.

Video 1. Zooplankton closest to the camera will jump or dart away from it. Source: GEMM Lab.

So, let us think about this for gray whales and their zooplankton prey. The latter are relatively immobile. Even though they dart around in the water column (I have seen them ‘jump’ away from the GoPro when we lower it from the kayak on several occasions; Video 1), they do not have the ability to maneuver away fast or far enough to evade a gray whale predator moving much faster. As such, the predator response will most likely always be the strongest since gray whales operate at a scale that is several orders of magnitude greater than the zooplankton. However, the zooplankton may not be as helpless as I have made them seem. Based on our field observations, it seems that zooplankton often aggregate beneath or around kelp. This behavior could potentially be an attempt to evade predators as the kelp and reef crevices may serve as a refuge. So, in areas with a lot of refuges, the prey response may in fact dominate the relationship between gray whales and zooplankton. This example demonstrates the importance of habitat in shaping predator-prey interactions and behavior. However, we have often observed gray whales perform “bubble blasts” in or near kelp (Video 2). We hypothesize that this behavior could be a foraging tactic to tip the see-saw of predator-prey response strength back into their favor. If this is the case, then I would imagine that gray whales must decide whether the energetic benefit of eating zooplankton hidden in kelp refuges outweighs the energy required to pursue them (Fig. 2). On top of all these choices, are the potential risks and threats of boat traffic, fishing gear, noise, and potential killer whale predation (Fig. 1). Bringing us back to the analogy of economic analysis of costs and benefits to predator-prey relationships. I never realized it so clearly before, but gray whales sure do have a lot of decisions to make in a day!

Video 2. Drone footage of a gray whale foraging in kelp and performing a “bubble blast” at 00:40. Footage captured under NMFS permit #21678. Source: GEMM Lab.

Trying to tease apart these nuanced dynamics is not easy when I am unable to simply ask my study subjects (gray whales) why they decided to abandon a patch of zooplankton (Were the zooplankton too hard to obtain because they sought refuge in kelp, or was the patch unprofitable because there were too few or the wrong kind of zooplankton?). Or, why do gray whales in Oregon risk foraging in such nearshore coastal reefs where there is high boat traffic (Does their need for food near the reefs outweigh this risk, or do they not perceive the boats as a risk?). So, instead, we must set up specific hypotheses and use these to construct a thought-out and informed study design to best answer our questions (Mann 2000). For the past few weeks, I have spent a lot of time familiarizing myself with spatial packages and functions in R to start investigating the relationships between zooplankton and kelp hidden in the data we have collected over 4 years, to ultimately relate these patterns to gray whale foraging. I still have a long and steep journey before I reach the peak but once I do, I hope to have answers to some of the questions that the Cetacean Behavioral Ecology class has inspired.

Literature cited

Krebs, J. R., and N. B. Davies. 2012. Economic decisions and the individual in Davies, N. B. et al., eds. An introduction to behavioral ecology. John Wiley & Sons, Oxford.

Mann, J. 2000. Unraveling the dynamics of social life: long-term studies and observational methods in Mann, J., ed. Cetacean societies: field studies of dolphins and whales. University of Chicago Press, Chicago.

Sih, A. 1984. The behavioral response race between predator and prey. The American Naturalist 123:143-150.

Srinivasan, M. 2019. Predator/prey decisions and the ecology of fear in Würsig, B., ed. Ethology and ecology of odontocetes. Springer Nature, Switzerland.