Clara Bird, PhD Candidate, OSU Department of Fisheries, Wildlife, and Conservation Sciences, Geospatial Ecology of Marine Megafauna Lab

While I did not mean to start a mini-blog series on individual specialization, here I am with my third blog about individual specialization in as many years. Looking back, these blogs are actually a lovely documentation of my own journey of learning about individual specialization and I hope you’re enjoying being along for the ride.

So, what have we learned so far? In my first blog I described the concept of individual specialization, why it matters, and presented some case studies. In my second blog I discussed the roles of competition and learning as drivers of individual specialization. Let’s review: Individual specialization is when individuals within a population only use a subset of the resources that the full population uses, but different individuals use different subsets. This is important to quantify for two reasons: (1) it affects how we think about conserving and managing a population (Bolnick et al., 2003), and (2) it can affect the relationships between the population and the other species in its community (Bolnick et al., 2011). Common drivers of specialization are competition and learning. Competition can lead to specialization because it reduces the availability of a resource, driving individuals to switch resource use (Pianka, 1974). Learning can also lead to specialization through ‘one-to-one’ learning, where one individual learns from one demonstrator (Sheppard et al., 2018). This individual tends to then use, and eventually teach, that specialized technique.

While understanding these drivers is important, the question of why specific individuals employ specific specializations remains. If learning is not the driver of specialization, then how do individuals end up using their specific subset. Is it random? Or are there underlying patterns? The common sources of variation are related to sex, age, or size (and often these three can be inter-connected) (Dall et al., 2012). 

Individual differences related to the sex of the individuals are called sexual dimorphisms. Physical and ecological differences between the sexes are common throughout nature (peacocks for example) and these differences can lead to different specializations. Northern elephant seals provide a fascinating example (Kienle et al., 2022). Northern elephant seal males are the distinctly larger sex as they engage in competitionfor females. Because of their larger body size and energy expenditure during competition, they have much higher energetic requirements than females during the breeding season, meaning that they need to consume more prey. This elevated requirement has led to a difference in foraging behaviors. Males forage near the continental shelf where there is more prey while females forage further offshore in the open ocean. However, the tradeoff of feeding on the continental shelf is an increased predation risk due to overlap with predator habitat, and indeed Kienle et al. found that the mortality rate for foraging trips was 5-6 times higher for males than females. So, while males need to take the risk of foraging in an area with higher predator presence to meet their energetic demands, females can forage in a safer habitat with less prey because their energetic requirements are lower. This study presents an excellent example of how sexual dimorphism can cause individual specialization and the subsequent consequences.

Individual specializations attributed to differences between distinct morphs are called resource polymorphisms. A morph is the physical appearance of an individual; distinct morphs are when there are clearly different kinds of morphs within a population. Morphs can range from color polymorphism (ex. lizards of different colors within the same species) to differences in skull shape and size. A study on the European eel found that differences in skull morphology were related to different foraging strategies (Cucherousset et al., 2011).  Eels with larger head widths consumed larger prey types. Interestingly, they found that eels on either end of the head width spectrum (i.e., very narrow or very wide) were more successful (i.e., in better body condition) than eels with intermediate head widths. They suggest that this difference in nutrition success is because the intermediate head width eels were less efficient foragers than eels at the extremes. In this example we see that morphology is related to the ability to feed on a prey type and has consequences for individual health.

Individual differences related to changes in size, shape, and behavior that occur as an individual grows are called ontogenetic shifts. As you have experienced yourself, there are many changes that occur as an individual grows, and these changes can mean that different age classes have different specializations. Gustafsson (1988) found an ontogenetic shift in where coal tits (a species of bird) fed within a pine tree. Younger birds were more generalists but tended to feed on the outer sections of the tree, while adults foraged on the more profitable, central portion of the tree. He attributes this difference to dominance of adults over juveniles. Gustafsson also found that the larger individuals within each age class also tended to feed closer to the center of the tree. This within age class difference is attributed to a larger body size being better suited for feeding closer to the center of the tree, while smaller body sizes are better suited for hovering and foraging on the outside. Interestingly, this study occurred over multiple years, and Gustafsson documented several juvenile individuals that shifted foraging behavior when they became adults. 

These sources of behavioral variation are important to account for because ultimately phenotypic variation can affect not only a population’s niche, but its population size, distribution, evolutionary potential, and vulnerability to environmental change (Wennersten & Forsman, 2012). And it’s important to determine which source(s) of variation are at play to inform best population management practices. Different behaviors between sexes versus age classes have different implications for the population, making it necessary to not only assess if there are differences but also to try and understand their drivers.

This behavioral variability relative to morphs is something that is of particular interest to me, and it is the focus of my first chapter. We’ve documented that the PCFG gray whales in our study region employ a variety of foraging tactics, and I want to know if there is specialization in tactic use and if we can find an underlying source of the variation. I can’t wait to share results with you in the next installment of this individual specialization journey. Stay tuned!

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References

Bolnick, D. I., Amarasekare, P., Araújo, M. S., Bürger, R., Levine, J. M., Novak, M., Rudolf, V. H. W., Schreiber, S. J., Urban, M. C., & Vasseur, D. A. (2011). Why intraspecific trait variation matters in community ecology. Trends in Ecology & Evolution, 26(4), 183–192. https://doi.org/10.1016/j.tree.2011.01.009

Bolnick, D. I., Svanbäck, R., Fordyce, J. A., Yang, L. H., Davis, J. M., Hulsey, C. D., & Forister, M. L. (2003). The ecology of individuals: Incidence and implications of individual specialization. American Naturalist, 161(1), 1–28. https://doi.org/10.1086/343878

Cucherousset, J., Acou, A., Blanchet, S., Britton, J. R., Beaumont, W. R. C., & Gozlan, R. E. (2011). Fitness consequences of individual specialisation in resource use and trophic morphology in European eels. Oecologia, 167(1), 75–84. https://doi.org/10.1007/s00442-011-1974-4

Dall, S. R. X., Bell, A. M., Bolnick, D. I., & Ratnieks, F. L. W. (2012). An evolutionary ecology of individual differences. Ecology Letters, 15(10), 1189–1198. https://doi.org/10.1111/j.1461-0248.2012.01846.x

De Meyer, J., Belpaire, C., Boeckx, P., Bervoets, L., Covaci, A., Malarvannan, G., De Kegel, B., & Adriaens, D. (2018). Head shape disparity impacts pollutant accumulation in European eel. Environmental Pollution, 240, 378–386. https://doi.org/10.1016/j.envpol.2018.04.128

Gustafsson, L. (1988). Foraging behaviour of individual coal tits, Parus ater, in relation to their age, sex and morphology. Animal Behaviour, 36(3), 696–704. https://doi.org/10.1016/S0003-3472(88)80152-0

Kienle, S. S., Friedlaender, A. S., Crocker, D. E., Mehta, R. S., & Costa, D. P. (2022). Trade-offs between foraging reward and mortality risk drive sex-specific foraging strategies in sexually dimorphic northern elephant seals. Royal Society Open Science, 9(1), 210522. https://doi.org/10.1098/rsos.210522

Pianka, E. R. (1974). Niche Overlap and Diffuse Competition. 71(5), 2141–2145.

Sheppard, C. E., Inger, R., McDonald, R. A., Barker, S., Jackson, A. L., Thompson, F. J., Vitikainen, E. I. K., Cant, M. A., & Marshall, H. H. (2018). Intragroup competition predicts individual foraging specialisation in a group-living mammal. Ecology Letters, 21(5), 665–673. https://doi.org/10.1111/ele.12933

Wennersten, L., & Forsman, A. (2012). Population-level consequences of polymorphism, plasticity and randomized phenotype switching: A review of predictions. Biological Reviews, 87(3), 756–767. https://doi.org/10.1111/j.1469-185X.2012.00231.x

Imogen Lucciano, Graduate student, OSU Department of Fisheries, Wildlife, & Conservation Sciences, Geospatial Ecology of Marine Megafauna Lab. 

Work in the GEMM lab is booming in all different directions of whale research, and so taking turns writing for the GEMM lab blog gives all of its members an opportunity to highlight topics that are specific and current to us individually. I am two-thirds of the way done with my MSc thesis program, and I’ve recently begun speaking publicly about my work on the HALO project and fin whale acoustic detection off the Oregon coast. In this blog I’ll highlight a two-part question that I am often asked, “Can you see more than fin whales in the data, and how can you tell the species apart when you are looking at it?”. These questions provide great ponderance and are very significant to what I am trying to accomplish. The answer is that I absolutely can see other whales when I am looking through the acoustic data and in fact I have to be quite meticulous in my efforts to tease them apart at times. Let me explain:

The acoustic data set I am working with tells an important story of the waters off the Oregon coast and will illuminate researchers (and the public) on the presence of all detectable vocal whales and dolphins in the area over the past year, from October 2021 to January of 2023. The advanced technological recording systems, called Rockhoppers, that HALO deploys off the coast of Newport, provide us with continuous sound files for the entire time that they are deployed. (I previously wrote a short blog on Rockhoppers, for those interested in more information.) Then, we analysts (graduate students) on the project work to establish the acoustic presence of our target species within those files.

Based on what experts in the field of cetacean bioacoustics currently understand about fin whales, they produce sounds at a very low frequency for both socializing (presumably their 20 Hz pulse call) and for foraging (presumably their 40 Hz downsweep call) (Sirovic et al. 2013; Romagosa et al. 2021). During my efforts to determine the presence of fin whales, it is relatively easy to identify the 20 Hz pulse call, since this call has been well documented in the literature and is the only cetacean call described that occurs in its frequency range. I look for these calls in spectrogram representations of the acoustic data, which allow me to see the selected frequency range over our data collection period (time; Figure 1).

Where this process becomes complicated for me is when I look for the 40 Hz fin whale downsweep call, which is known to occur between ~ 75 Hz – 30 Hz (Wiggins & Hildebrand 2020; Romagosa et al. 2021). This call can vary slightly within this frequency range. Interpretation of this call reaches even higher ambiguity when there are blue whales and sei whales acoustically detected in the same time frame in the same area. The acoustic repertoire of both blue and sei whale calls fall in the same frequency range: blue whales producing what is known as “D calls” and sei whales are known to make low-frequency downsweep calls (Figure 2; Sirovic et al. 2013; Romagosa et al. 2020).

At first glance, the vocalizations from these three whales can be easily confused, and so I am looking for finer details to help tease out the fin whale downsweeps. As shown in Figure 2, there is a difference in the behavior of these calls, with the sei whale call being a shorter call by a matter of 2-3 seconds. The sei whale downsweep calls have not been frequently described in the literature, however those few publications report these calls occurring over 1.4-1.6 seconds (Baumgartner et al. 2008; Espanol-Jimenez et al. 2019) and in each published spectrogram, I have observed this similar boomerang-type looking behavior in the call. Blue whale D calls, on the other hand, are calls produced as social calls while foraging (Szesciorka et al 2020) and known to occur over ~1.8 seconds (Oleson et al. 2007).  

Fin whale 40 Hz calls have a duration of about one second and are not known to be produced in a regular sequence (Sirovic et al. 2013), thus I am teasing them out carefully from what can sometimes appear like a diversly grouped choir of low frequency whale song among the HALO data (Figures 3 & 4).  

Although there are some known seasonal patterns of each of these aforementioned whale calls (Sirovic et al. 2013; Szesciorka et al. 2020), many data gaps remain of the temporal patterns of the 40 Hz and 20 Hz calls (i.e., when the calls occur) off the Oregon coast. Therefore, I cannot assume that I will only see 40 Hz calls in any time period. I need to assess the behavior of the calls I detect and tease out the calls I know surely are fin whale 40 Hz downsweeps in each file of the entire acoustic dataset.

Afterthought: The HALO project is new and has only just collected its first year of acoustic data, however the project is intent to continue deploying and collecting Rockhoppers off the Oregon coast for years to come. As this acoustic data set continues to grow it will be used by other researchers, and I (among the first to process and analyze it) feel some pressure to get things done right. As I process these data I will work hard to make the best-informed call identifying fin whales in the 40 Hz range. This focus and feeling of responsibility reassure me that I am in the appropriate career field. I really care about how these data are processed, where the research will go from here, and how it influences human activities in this critical whale habitat.

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References

Baumgartner, M., Van Parijs, S., Wenzel, F., et al. 2008. Low frequency vocalizations attributed to sei whales. Acoustical Society of America, 124 (2): 1339-1349. https://www.whoi.edu/cms/files/JAS001339_59390.pdf.

Espanol-Jimenez, S., Bahamonde, P., Chiang, G., Haussermann, V. 2019. Discovering sounds in

Oleson, E., Calambokidis, J., Burgess, W,. et al. 2007. Behavioral context of call production by eastern North Pacific blue whales. Marine Ecology Progress Series, 330 : 269-284. https://www.int-res.com/articles/meps_oa/m330p269.pdf.

Romagosa, M., Baumgartner, M., Cascao, I., et al. 2020. Baleen whale acoustic presence and behavior at a Mid-Atlantic migratory habitat, the Azores Archipelago. Scientific Reports, 10. https://www.researchgate.net/publication/339952595_Baleen_whale_acoustic_presence_and_behaviour_at_a_Mid-Atlantic_migratory_habitat_the_Azores_Archipelago.

Romagosa, M., Perez-Jorge, S., Cascao, I., et al. 2021. Food talk: 40-Hz fin whale calls are associate with prey biomass. Proceedings of the Royal Society B: Biological Sciences, 288 (1954): 20211156. https://pubmed.ncbi.nlm.nih.gov/34229495/.

Sirovic, A., Williams, L., Kerosky, S., Wiggins, S., Hildebrand, J. 2013. Temporal separation of two fin whale call types across the eastern North Pacific. Marine Biology, 160: 47-57.

Szesciorka, A., Ballance, L., Sirovic, A., et al. 2020. Timing is everything: drivers of interannual variability in blue whale migration. Scientific Reports, 10 (7710). https://www.nature.com/articles/s41598-020-64855-y. Wiggins, S. & Hildebrand, J. 2020. Fin whale 40 Hz behavior studied with an acoustic tracking array. Marine Mammal Science, 36 (3). https://www.researchgate.net/publication/339575220_Fin_whale_40-Hz_calling_behavior_studied_with_an_acoustic_tracking_array.

Allison Dawn, GEMM Lab Master’s student, OSU Department of Fisheries, Wildlife and Conservation Sciences, Geospatial Ecology of Marine Megafauna Lab 

If you have followed the GEMM Lab blog for a while, you have read about the multitude of techniques we use to conduct research. A combination of platforms and technologies help us observe whales: rigid inflatable boats (RHIBs), kayaks, theodolites, cameras, binoculars, high-tech drones, and more. However, not only do we observe from the sky and sea surface, but we also know it is important to monitor whale behavior, habitat, and prey underwater. For this week’s blog, I’d like to highlight the GEMM Lab’s sub-surface efforts as part of the TOPAZ/JASPER project, and share more about the world of scientific diving.

Most terrestrial ecologists have the luxury of strolling through their study systems without having to give thought to their next breath, but marine scientists need creative, streamlined, and most importantly, life-preserving ways to directly observe the ocean environment. Like most inventions, today’s self-contained underwater breathing apparatus (SCUBA) equipment was developed from countless prototypes worldwide, dating as far back as the 1800s. This equipment was improved during World War II, specifically to support combat swimmers (called “frogmen” at the time). After the Franco-German Armistice of 1940, French engineer Émile Gagnan and Naval Lieutenant/Oceanographer Jacques Cousteau teamed up to invent the “Aqua-Lung” (Fig. 1), which allowed divers to autonomously stay underwater for much longer periods of time. 

Figure 1: Vintage advertisement for the Aqua-Lung (left) and a diver testing out the equipment (right). Photos sourced from https://us.aqualung.com/en/ourstory.html

Now that the first commercially successful breathing apparatus was available, universities began to purchase these units to aid with scientific exploration. However, after a series of fatal diving accidents, the Scripps Institution of Oceanography felt it was urgent to develop the first scientific diving safety program in 1954, years before recreational diving courses were implemented. With specific tasks at hand, the additional level of distraction makes safety and situational awareness that much more important. Now, scientific dive programs, like the one at OSU, are widespread, and after proper safety precautions and training, researchers have been able to accomplish what was previously implausible: restore coral reefs, obtain genetic information from invasive species, monitor species under polar ice sheets, and so much more (Fig. 2).

Figure 2: Scientific divers at work. Norwegian polar ice diver Michal Tessman collects algae, zooplankton, and phytoplankton samples (left); Florida State doctoral student Nathan Spindel obtains genetic material from urchins (top right); Dr. Colleen Bove of UNC Chapel Hill monitors tropical coral growth (bottom right).

On the south coast of Oregon, the GEMM lab collaborates with Dr. Aaron Galloway, an accomplished scientific diver and one of the lead scientists with the Oregon Kelp Alliance (ORKA), an organization dedicated to kelp forest monitoring, urchin culling, and restoration efforts. He and his team, along with our long-term project partner Dave Lacey of South Coast Tours, help us deploy our in situ underwater cameras each summer (Figs 3 & 4). As you may know, the TOPAZ component of our project aims to link fine-scale gray whale foraging ecology to prey distribution patterns, using inexpensive field methods. The in situ underwater CamDO camera systems are an exciting, recent addition to our long-standing sampling approach.

Figure 3: CamDo lander with attached oceanographic sensors (left); two new OSU scientific divers and Marine Studies Initiative interns, Faith Townsend and Caroline Rice, preparing to dive (right).

We have two durable camera housings that anchor in Mill Rocks and Tichenor Cove. In each housing we insert a GoPro, an extra battery, and a microcontroller programmed to record footage at continuous intervals. With these cameras we capture hundreds of hours of underwater footage of fish, zooplankton, and we hope to one day record gray whale foraging.

Figure 4: Dr. Aaron Galloway and his graduate student Samantha Persad getting ready to complete the final dive of the season in ideal visibility conditions.

Each week during the field season, the divers and I meet early at the dock to board the tour boat Black Pearl for our routine CamDO maintenance excursions. My first role on the early morning journeys is to be a “dive tender” — I help the divers back on board, log their dive times and air pressure, and keep gear organized on the boat. Then, while the divers relax and enjoy a snack, my next role begins. The next few minutes is what we refer to as the “NASCAR pit-stop” of camera maintenance: I replace batteries, swap SD cards, program the camera, ensure that it is secure in the housing, and tuck it into the diver’s bag along with installation tools. All the while, I simultaneously listen for radio calls from our Port Orford interns, sometimes troubleshooting urgent questions while they collect zooplankton and water quality data from the kayak or observe for whales from the cliff.

This multitasking is challenging, but at least I am dry, warm, and have total dexterity of my hands. As I watch the divers descend, in all their neoprene glory, to secure the camera back to its stationary landing, I like to imagine what they are seeing and experiencing. If visibility is good, they will descend into a cerulean blue world filled with rockfish, jellies, mysid swarms, and algae covered reefs (Fig 5.). However, as exciting as sightseeing can be while diving, my own scientific diver training has allowed me to understand the focus, determination, and adaptability even the simplest of tasks require, especially in the chilly waters of the Pacific Northwest.

Figure 5: Under the surface: black rockfish enjoying a swim around the rocky reefs in Tichenor Cove, Port Orford.

I earned my AAUS Scientific Diver certification in 2018 through UNC Chapel Hill, and have since learned just how different cold water is from warm water diving. My first cold water dive was at the Orford Reef exhibit in the Oregon Coast Aquarium. Guided by Kevin Buch, OSU’s Diving and Boat Safety Officer, I gained a new respect for how important it is to train in the conditions you will be working in. For example, cold-water diving requires much more insulation, which in turn changes your buoyancy and dexterity. At first, I struggled to learn my new buoyancy baseline while simultaneously rolling out transect tape with thick neoprene gloves and keeping a curious sturgeon from stealing my mask. At times it felt like I was learning to dive all over again. This winter, I have increased my confidence by taking evening SCUBA proficiency courses to sharpen my skills and logging dives in local conditions.

Figure 6: Obtaining my open water certification on the French Reef in Florida Keys, 2018.

As part of our Advanced Diver weekend course in the beautiful Hood Canal, I had the opportunity to hone my skills in compass navigation, buoyancy, night and deep dives, and search & recovery methods, all in my new cold water gear. While my dive buddy and I were ecstatic to see some amazing flora and fauna (giant pacific octopus, sea pens, nudibranch, pipefish, and more!) we mainly bonded over the shared sense of achievement in safely completing our complex tasks in low-visibility, cold-water conditions.

Figure 7: Giant Pacific Octopus like this can be observed while diving in the Hood Canal, photo credit Bruce Kerwin.

As I complete these trainings, I think of all there is to to be discovered with data collected under the surface of our Port Orford study system: the health of kelp forests, the density and patchiness of mysid shrimp (the crucial prey source for gray whales), habitat complexity, and more. I am curious if there are certain puzzle pieces driving gray whale foraging decisions that may be revealed through expanding our subsurface monitoring efforts as part of the GEMM Lab’s already impressive dataset.

The skill sets required for scientific diving are also useful for outdoor leadership, and truly in all situations: maintaining a cool head under stressful conditions, planning for the unexpected, managing expectations, and communicating well (you can’t really talk with a regulator in your mouth!) — to name just a few. Regardless of exactly how I use my scientific dive training for future research, I am thankful for all this experience has taught me; and, I look forward to integrating these skills further as we head into our 9th year of the JASPER/TOPAZ project.

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

Another year has come and gone, and with the final days of 2022 upon us, it is my honor and pleasure to present to you, dear reader, this summary of achievements by the GEMM Lab this year. It has been another big year for us, so snuggle up with your favorite holiday drink and enjoy our recap of 2022!

2022 was a huge year of milestones for each lab member. The biggest happened just a few weeks ago when, on December 1^st, our primary investigator (PI) and the captain at the GEMM Lab helm, Leigh Torres, started her sabbatical!!! Leigh, who received tenure and became an Associate Professor in 2020, was eligible for a sabbatical this year and took the opportunity to take a very well-deserved three months in New Zealand with her family. Leigh established the GEMM Lab in 2014, and it has since grown into a 13-person strong team that aims to advance marine science and conservation through innovative and engaged research across 11 active projects. I know I speak for all my lab mates when I say that we are incredibly grateful and thankful for Leigh, who always prioritizes us, even when she is busy with other things. Leigh, enjoy New Zealand and your time off! Your crew will man the GEMM Lab ship while you are away, under the leadership of the four postdocs, your first mates. Speaking of which…

Dawn Barlow defended her PhD dissertation “Ecology and Distribution of Blue Whales in New Zealand Across Spatial and Temporal Scales” in April and became the latest Dr. of the GEMM Lab! Dawn’s achievements were recognized by OSU’s College of Agricultural Sciences as she was awarded the prestigious Savery Outstanding Doctoral Student Award in the spring. Finishing her PhD also marked the culmination of a decade of blue whale research in New Zealand, which began with Leigh’s hypothesis of a resident blue whale population in the region. Thankfully, we have not had to say goodbye to Dawn as she is now a GEMM Lab postdoctoral scholar (more below). The milestones kept coming after Dawn’s defense as PhD student Clara Bird became PhD candidate Clara Bird in April after passing her qualifying exams. Four of us – MS students Allison Dawn and Imogen (also called Miranda) Lucciano, and PhD students Rachel Kaplan and myself – successfully defended our research proposals to our committees and had fruitful discussions about how to best accomplish our ambitious proposed research. Morgan O’Rourke-Liggett rejoined the GEMM Lab after being the undergraduate intern in the 2017 TOPAZ/JASPER (Theodolites Overlooking Predators and Prey / Journey for Aspiring Students Pursuing Ecological Research) field season, and they completed their graduate certificate in Geographic Information Systems in the Fall. For their capstone project, Morgan is now working on accounting for GRANITE (Gray whale Response to Ambient Noise Informed by Technology and Ecology) survey effort in order for us to then understand whether and how distribution patterns of gray whales have changed. Finally, Imogen completed her Graduate Certificate of Wildlife Management and moved into an M.Sc. program. Hip-hip-hurrah for all of these degree milestones!

This year, it felt like someone in the GEMM Lab was always either preparing for fieldwork, in the field, or completing the post-fieldwork tasks of gear maintenance and data download. This reality is not surprising given that we have five active projects that involve fieldwork, which keep us busy on the ocean. Another two successful gray whale field seasons are on the books! Our project GRANITE wrapped its 7^th consecutive year of field work in Newport on October 15^th, while the integrated projects TOPAZ/JASPER completed an 8^th consecutive field season in Port Orford at the end of August. The GRANITE field team grew with the addition of Master’s student Kate Colson, who is co-advised by Leigh and Dr. Andrew Trites at University of British Columbia. Down south in Port Orford, Allison successfully led her first solo field season after taking over the project from me last year. But the nearshore is not the only place that captured the GEMM Lab’s attention. HALO (Holistic Assessment of Living marine resources off Oregon) completed three survey cruises in January, June, and July, which included the successful recovery and replacement of three hydrophones, providing Imogen and Cornell PhD student Marissa Garcia with their long-awaited acoustic data. Imogen oversees cruise coordination for this GEMM Lab effort, and several lab members have gone to sea for HALO, including Imogen, Rachel, Dawn and Leigh. We also continued our participation in the Northern California Current (NCC) cruises, where we collect marine mammal and krill data for the OPAL (Overlap Predictions About Large whales) project. Dawn, Rachel and Clara all headed out together on NOAA’s R/V Bell M. Shimada in May, while Rachel was the sole GEMM Lab representative on the September cruise. Offshore biopsy efforts and U.S. Coast Guard helicopter flights also contributed data to OPAL through the year. Finally, Leigh and Dawn also participated in the MMI-wide MOSAIC (Marine Offshore Species Assessment to Inform Clean energy) cruises in August and October. Despite spending so many hours on the water, we were productive onshore too…

Our faraway postdoc Solène, who has been working remotely from New Caledonia, has made steady progress on the OPAL project. Her biggest achievement this year was finishing the first, NOAA section 6-funded component, and helping to acquire funding for the second phase of the project, which Rachel started work on for her PhD. We were lucky to have Solène visit the lab in January, where she met the new and reunited with the old faces of the GEMM Lab. While her time in Oregon was only 6 weeks or so, we managed to rope her into her first and second gray whale paper (stay tuned for that sometime in 2023). And to top off our quest of making Solène an Oregonian, we are so thrilled to announce that she and her husband Micah have finally acquired their visas to move here in just a few weeks, landing in January 2023!!

We have been, and continue to be, busy processing and analyzing all of the rich datasets that we collect during our intense field efforts. While I do not have time to mention all of the work that occurs in the lab and on our computers, I want to highlight some of them. Our postdoctoral scholar Alejandro A. Fernández Ajó is currently back at his graduate institute, Northern Arizona University, conducting lab work to analyze the 63 fecal samples collected from 26 individual gray whales during our 2022 GRANITE field season. Rachel and her amazing team of krill interns have been doing lots of bomb calorimetry all year to better understand the caloric value of different krill species and cohorts. Imogen spent a month at Cornell University in Ithaca, New York, to hone her skills for baleen whale recognition in acoustics data and to become well acquainted with OSU affiliates Dr. Holger Klinck, PhD student Marissa Garcia, and other researchers at the K. Lisa Yang Center of Conservation Bioacoustics. 

Even with all these projects underway, it seems that we cannot go a full year in the GEMM Lab without launching new endeavors. 2022 saw the creation of two more projects. For her postdoctoral research, Dawn is leading the newly-launched EMERALD (Examining Marine mammal Ecology through Region-wide Assessment of Long-term Data), which investigates spatiotemporal distribution patterns in harbor porpoise and gray whales in the nearshore NCC waters. Secondly, postdoctoral scholar KC Bierlich and Leigh have received funding to kickstart MMI’s Center of Drone Excellence (CODEX), which will launch in 2023. CODEX will focus on developing open-source tools and software to help analyze drone imagery, with the aim of offering online tutorials and hosting workshops. Both EMERALD and CODEX are funded by sales and renewals of the special Oregon gray whale license plate, which benefits MMI. We gratefully thank all the gray whale license plate holders, who made this research possible, and encourage any Oregonians that don’t have a whale on their tail yet, to do so in 2023!

Describing a year in the life of the GEMM Lab would not be complete without mentioning our outreach and education efforts as well. Allison, Clara, and I put on our teaching hats and gave guest lectures and labs for Dr. Renee Albertson and Dr. Kate Stafford’s marine mammal classes here at OSU as well as host an Introduction to R/RStudio workshop for undergraduates in our roles as coordinators for the Fisheries & Wildlife Mentorship Program. Alejandro gave a virtual talk to graduate students at the University of Pretoria South Africa about conservation physiology, highlighting his research with southern right whales. KC was invited to talk about using drones and computer science to study whales at Newport High School’s Computer Science Course and Oregon Sea Grant’s Whale Ecology Homeschool Program. He also gave the keynote presentation at the 25^th Annual Salmon Bowl, part of the National Oceanic Sciences Bowl, which was hosted by OSU in February. Clara and myself were both invited speakers for Cape Perpetua’s monthly speaker series, where we presented our PhD research. Furthermore, GEMM Lab members also presented our work at numerous scientific conferences including the Society of Marine Mammal conference, Ocean Sciences, PICES annual meeting, and TWS Oregon Chapter, to name a few. The dissemination of our work to the scientific community and the public is a central focus of our lab, and we also prioritize providing hands-on opportunities and experiences to students eager to participate in ecological research. We mentored a total of 12 students in 2022, from high school to graduate level, who were involved in all aspects of our research including kayaking in Port Orford to collect prey samples, meticulously measuring drone images of whales, and spending hours hunched over microscopes identifying tiny crustaceans. 

We have once again been prolific writers, contributing 19 total peer-reviewed publications to 15 different scientific journals. If you are in the mood for some holiday reading, you will find the full list of publications at the end of this post. All authors in bold are (or were) GEMM Lab members when the work occurred.

And YOU, our awesome, supportive readers, have once again been busy, with a whopping 25,368 views of our blog this year!!! Thank you for joining us on our 2022 journey! We hope you have enjoyed the tales that we have told and the knowledge we have (hopefully) conveyed. On one final note, if you are still looking for that perfect holiday gift for the whale-lover in your life, and if you want to support our research, consider adopting a whale from our IndividuWhale website. As a small incentive, if you adopt a whale before the end of the year, you will be entered into our Oregon South Coast Whale Watch Experience giveaway! We will reveal the giveaway winner in January 2023. We wish you all restful, happy, and most importantly, healthy holidays, and hope you will join us again in 2023!

Did you enjoy this blog? Want to learn more about marine life, research, and conservation? Subscribe to our blog and get a weekly message when we post a new blog. Just add your name and email into the subscribe box below.

Publications

Barlow, D.R., Klinck, H., Ponirakis, D., Holt Colberg, M., Torres, L.G. (In Press). Temporal occurrence of three blue whale populations in New Zealand waters from passive acoustic monitoring. Journal of Mammalogy.

Barlow, D.R., Estrada Jorge, M., Klinck, H., Torres, L.G. (2022). Shaken, not stirred: blue whales show no acoustic response to earthquake events. Royal Society Open Science. 9:220242.

Bierlich, K.C., Hewitt, J.,  Schick R.S., Pallin, L., Dale, J., Friedlaender, A.S., Christiansen, F., Sprogis K.R., Dawn, A.H., Bird, C.N.,  Larsen, G., Nichols, R., Shero, M., Goldbogen, J.A., Read, A., Johnston, D.W. (2022). Seasonal gain in body condition of foraging humpback whales along the Western Antarctic Peninsula. Frontiers in Marine Science. 9, 1–16. https://www.frontiersin.org/articles/10.3389/fmars.2022.1036860/full   

Cade, D.E., Kahane-Rapport, S.R., Gough, W.T., Bierlich, K.C., Linksy, J.M.J., Johnston, D.W., Goldbogen, J.A., Friedlaender, A.S. (in press). Ultra-high feeding rates of Antarctic minke whales imply a lower limit for body size in engulfment filtration feeders. Nature Ecology and Evolution.

D’Agostino, V.C., Fernández Ajó, A., Degrati, M. et al. Potential endocrine correlation with exposure to domoic acid in Southern Right Whale (Eubalaena australis) at the Península Valdés breeding ground. Oecologia 198, 21–34 (2022). https://doi.org/10.1007/s00442-021-05078-4

Derville, S., Barlow, D.R., Hayslip, C., Torres, L.G. (2022). Seasonal, annual, and decadal shifts of three baleen whale species relative to dynamic ocean conditions off Oregon, USA. Frontiers in Marine Science 9:868566.

Goetz, K.T., Stephenson, F., Hoskins, A., Bindoff, A.D., Orben, R.A., Sagar, P.M., Torres, L.G., et al. (2022). Data quality influences the predicted distribution and habitat of four southern-hemisphere Albatross species. Frontiers in Marine Science 9:782923. https://doi:10.3389/fmars.2022.782923  

Gough, W.T., Cade, D.E., Czapanskiy, M.F., Potvin, J., Fish, F.E, Kahane-Rapport, S.R., Savoca, M.S., Bierlich, K.C., Johnston, D.W., Friedlaender, A.S., Szabo, A., Bejder, L., Goldbogen, J.A., (2022). Fast and Furious: Energetic tradeoffs and scaling of high-speed foraging in rorqual whales. Integrative Organismal Biology, 4(1) obac038,  https://doi.org/10.1093/iob/obac038

Green, C-P., Ratcliffe, N., Mattern, T., …, Torres, L.G., Hindell, M.A. (2022). The role of allochrony in influencing interspecific differences in foraging distribution during the non-breeding season between two congeneric crested penguin species. PLoS ONE https://doi.org/10.1371/journal.pone.0262901

Hildebrand, L., Sullivan, F.A., Orben, R.A., Derville, S., Torres, L.G. (2022). Trade-offs in prey quantity and quality in gray whale foraging. Marine Ecology Progress Series 695:189-201. https://doi.org/10.3354/meps14115   

Hunt, K.E., Buck, C.L., Ferguson, S.H., Fernández Ajó, A., Heide-Jørgensen, M.P., Matthews, C.J.D. (2002). Male Bowhead Whale Reproductive Histories Inferred from Baleen Testosterone and Stable Isotopes, Integrative Organismal Biology, 4: obac014, https://doi.org/10.1093/iob/obac014

Lemos, L.S., Haxel, J.H., Olsen, A., Burnett, J.D., Smith, A., Chandler, T.E., Nieukirk, S.L., Larson, S.E., Hunt, K.E., Torres, L.G. (2022). Effects of vessel traffic and ocean noise on gray whale stress hormones. Scientific Reports 12:18580.

Mouton, T.L., Stephenson, F., Torres, L.G., Rayment, W., Brough, T., McLean, M., Tonkin, J.D., Albouy, C., Leprieur, F. (2022). Spatial mismatch in diversity facets reveals contrasting protection for New Zealand’s cetacean biodiversity. Biological Conservation 267:109484. https://doi.org/10.1016/j.biocon.2022.109484

Nazario, E.C., Cade, D.E., Bierlich, K.C., Czapanskiy, M.F., Goldbogen, J.A., Kahane-Rapport, S.R., van der Hoop, J.M., San Luis, M.T., Friedlaender, A.S. (2022). Baleen whale inhalation variability revealed using animal-borne video tags. PeerJ 10:e13724 https://doi.org/10.7717/peerj.13724

Pallin, L., Bierlich, K.C., Durban, J. Fearnbach, H., Savenko, O., C.S. Baker, E. Bell, Double, M.C., de la Mare, W., Goldbogen, J., Johnston, D.,  Kellar, N., Nichols, R., Nowacek, D., Read, A.J., Steel, D., Friedlaender, A. (2022) Demography of an ice-obligate mysticete in a region of rapid environmental change. Royal Society of Open Science. 9(11).  https://doi.org/10.1098/rsos.220724

Reisinger, R.R., Brooks, C.M., Raymond, B., …, Torres, L.G., et al. (2022). Predator-derived bioregions in the Southern Ocean: Characteristics, drivers and representation in marine protected areas. Biological Conservation 272:109630. https://doi.org/10.1016/j.biocon.2022.109630

Rivers, J.W., Guerrero J.B., Brodeur, R.D., …, Torres. L.G., Barth, J.A. (2022). Critical research needs for forage fish within inner shelf marine ecosystems. Fisheries 47(5):213-221. https://doi.org/10.1002/fsh.10725

Segre P.S., Gough, W.T., Roualdes, E.A., Cade, D.E., Czapanskiy, M.F., Fahlbush, J., Kahane-Rapport, S.R., Oestreich, W.K., Bejder, L., Bierlich, K.C., Burrows, J.A., …Goldbogen, JA. (2022). Scaling of maneuvering performance in baleen whales: larger whales outperform expectations. Journal of Experimental Biology. 225 (5): jeb243224. https://doi.org/10.1242/jeb.243224  

Torres, L. G., Bird, C. N., Rodríguez-González, F., Christiansen, F., Bejder, L., Lemos, L., Urban R, J., Swartz, S., Willoughby, A., Hewitt, J., & Bierlich, KC. (2022). Range-Wide Comparison of Gray Whale Body Condition Reveals Contrasting Sub-Population Health Characteristics and Vulnerability to Environmental Change. Frontiers in Marine Science, 9. https://www.frontiersin.org/article/10.3389/fmars.2022.867258

Allison Dawn, GEMM Lab Master’s student, OSU Department of Fisheries, Wildlife and Conservation Sciences, Geospatial Ecology of Marine Megafauna Lab 

In last week’s blog, GEMM Lab postdoc Dawn Barlow discussed the uncertain future of upwelling response to climate change and how findings from the Shanks et al., 2009 “Paradigm lost? . . .” study implies that nearshore systems are likely decoupled from offshore upwelling processes. In a follow up to that paper, Shanks and co-authors found that the heterogeneity of coastline morphology (i.e., rocky or sandy) across several Oregon nearshore study sites explained zooplankton retention differences. Indeed, not only are there differences between offshore and nearshore upwelling dynamics, but there are also site-specific factors to consider when it comes to understanding changes in zooplankton retention along the Oregon coast (Shanks et. al, 2010).

I spend a lot of time thinking about what drives the variability in abundance and distribution of zooplankton prey of gray whales at our Port Orford study site over our long-term study period (2015-2022). For this blog, I want to briefly touch on a few interconnected dynamics in this nearshore PCFG gray whale foraging site that may affect their prey availability. Specifically, the interplay between shoreline topography, temperature, and habitat complexity. 

Interplay between shoreline morphology and thermal fronts

Several years before the “Paradigm lost? . . .” paper, Shanks led a study that investigated how holoplankton (a group of plankton in which mysids and amphipods belong) retention varies across three sites near Cape Arago and one site in Port Orford (Shanks et a., 2003). Here the authors noted that the Port Orford Bight causes an “upwelling shadow”, which is a region of water protected from upwelling-favorable winds. This shadow results in a small-scale warm water feature in the lee of the Port Orford Bight, which may serve as an important retention and recirculation zone for primary productivity (Graham et al., 1997). Discovering this “upwelling shadow” was not the intention of this paper, so the depth and breadth of the warm water plume within our study area has yet to be mapped (see Figure 1 for another West Coast example). However, “upwelling shadows” can act as convergence zones associated with greater zooplankton biomass (Morgan & Fisher, 2010; Ryan et al., 2010, Woodson et al., 2007) and thus may be an important feature to consider in our spatial analyses of drivers of prey availability to gray whales in our Port Orford study region.

Figure 1. Example of an “upwelling shadow” in Monterey Bay. Remotely sensed oceanographic convergent zones (top panel) and sea surface temperature (SST; lower panel) changes over time: a) Sept 8th 2003, b) Sept 2nd 2004, c) Sept 26th 2004, and d) May 31st 2005. Each time period demonstrates that the lee side of Point Año Nuevo is consistently warmer than the surrounding area. Figure source: Ryan et al., 2020.

Habitat complexity: rugosity and kelp

Not only could the unique shoreline in Port Orford contribute to zooplankton aggregations, but the subtidal marine environment is characterized by a range of unique habitat types: rocky reef, kelp beds, and sandy bottom habitat. Structural habitat complexity has been well documented in coral reef systems to be strongly linked with zooplankton prey availability and biodiversity of planktonic grazers (Richardson et al., 2017; Darling et al., 2017; Kuffner et al., 2007; Gladstone, 2007). Structural complexity can be measured in various ways, but quantifying rugosity (or surface “roughness”) is a widely accepted approach. However, only a few studies have demonstrated predator response to rugose habitats in Oregon nearshore rocky reefs (Rasmuson et al., 2021), and there is a dearth of knowledge linking rugosity to marine mammal predation (Cimino et al., 2020). 

Rugosity serves several purposes in the marine environment. A rugose habitat creates micro-habitats for predator evasion, provides greater surface area for kelp recruitment (Cruz et al., 2014; Toohey et al., 2007), and generates turbulence that circulates vital micronutrients for filter-feeding zooplankton and ultimately drives foraging effort at fine scales (Ottersen et al., 2010). 

Figure 2. Example images of habitat rugosity as measured by SCUBA transects. A) High-relief coral habitat with B) quantified depth (m) over transect seconds (10 seconds = 1 meter) and C) Low-relief coral habitat with D) quantified depth (m) over transect seconds (10 seconds = 1 meter). Figure source: Dustan et al., 2013.

Rugosity-generated turbidity might also help explain the zooplankton abundance variation we see across our sampling stations in Port Orford. In Lisa’s recent work showing evidence for a trophic cascade, a decline in bull kelp is overall strongly linked to a decline in zooplankton and gray whale foraging in Port Orford. However, there are sampling stations that, despite a significant loss in kelp, still had an abundance of mysids and hosted gray whale feeding activity in 2021 and 2022. Could this mean that those rocky reef stations, which are more rugose than the sandy bottom habitats, produced enough turbulence to support zooplankton prey? This hypothesis is consistent with several studies that found kelp abundance becomes less relevant with increasing habitat complexity (Trebilco et al., 2016; Anderson, 1994; Choat & Ayling et al., 1987; Larson, 1984). 

There certainly may be other physical or oceanographic factors that create turbidity at these stations. However, as my REU mentee Zoe Sax has been investigating, we think that turbidity could be a metric of primary productivity, which supports zooplankton growth. 

Figure 3 is a map of the average secchi disk values, which provide us with a measure of turbidity (the deeper we see the disk the less turbidity) in 2021 at our 12 sampling stations and their relation to kelp cover. 

Last year was a low kelp year, but Mill Rocks still had a few bull kelp canopies. In Mill Rocks where there was rocky reef with kelp, we see secchi values were low (meaning turbidity was high). This is in contrast to the areas in the sandy bottom regions (no kelp, low rugosity: specifically MR16, TC4, TC6, and TC10) with the lightest values, meaning low turbidity. 

Then, in Tichenor Cove specifically, we see that station TC1 has very little kelp but high turbidity; interestingly this site was a favored foraging spot for gray whales in 2021 and happens to be the closest station to the “upwelling shadow” I described earlier. I hope to conduct rugosity measurements in the near future so we can investigate these linkages further.

Figure 3. Map of two study sites, Tichenor Cove and Mill Rocks, with twelve sampling stations in Port Orford, OR and their average secchi disk values (meters) in 2021. Kelp abundance shown in light green polygons. 

Conclusion

This focus on topography, temperature, and habitat complexity to understand zooplankton variation does not discount that upwelling is an important factor for Oregon nearshore ecology. Menge & Menge 2013 found that upwelling accounted for ~50% of ecological variance in rocky intertidal regions. However, these findings occurred across large spatial areas of about 100 km, while our TOPAZ  sampling in Port Orford is on a much finer scale. Variation in ecological patterns at different, hierarchical scales are well-documented (Levin, 1992; Ottersen et al., 2010). Uncovering the “mosaic of processes”, as Shanks et al., 2003 describes, that drives nearshore zooplankton dynamics is equally challenging as it is fascinating, and I look forward to sharing more results from my Master’s work soon.

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References

Anderson, T. W. (1994). Role of macroalgal structure in the distribution and abundance of a temperate reef fish. Marine ecology progress series. Oldendorf, 113(3), 279-290.

Choat, J. H., & Ayling, A. M. (1987). The relationship between habitat structure and fish faunas on New Zealand reefs. Journal of experimental marine biology and ecology, 110(3), 257-284.

Darling, E. S., Graham, N. A., Januchowski-Hartley, F. A., Nash, K. L., Pratchett, M. S., & Wilson, S. K. (2017). Relationships between structural complexity, coral traits, and reef fish assemblages. Coral Reefs, 36(2), 561-575.

Dustan, P., Doherty, O., & Pardede, S. (2013). Digital reef rugosity estimates coral reef habitat complexity. PloS one, 8(2), e57386.

Gladstone, W. (2007). Selection of a spawning aggregation site by Chromis hypsilepis (Pisces: Pomacentridae): habitat structure, transport potential, and food availability. Marine Ecology Progress Series, 351, 235-247.

Graham, W. M., & Largier, J. L. (1997). Upwelling shadows as nearshore retention sites: the example of northern Monterey Bay. Continental Shelf Research, 17(5), 509-532.

Kuffner, I. B., Brock, J. C., Grober-Dunsmore, R., Bonito, V. E., Hickey, T. D., & Wright, C. W. (2007). Relationships between reef fish communities and remotely sensed rugosity measurements in Biscayne National Park, Florida, USA. Environmental biology of fishes, 78(1), 71-82.

LARSON, R. J., & DeMARTINI, E. E. (1984). SAN ONOFRE, CALIFORNIA. Fishery Bulletin, 82(1-2), 37.

Levin, S. A. (1992). The problem of pattern and scale in ecology. Ecology, 73(6), 1943-1967.

Londoño Cruz et al. (2014) Londoño Cruz E, Mesa-Agudelo LAL, Arias-Galvez F, Herrera-Paz DL, Prado A, Cuellar LM, Cantera J. Distribution of macroinvertebrates on intertidal rocky shores in Gorgona Island, Colombia (Tropical Eastern Pacific) Revista de Biología Tropical. 2014;62(1):189–198. doi: 10.15517/rbt.v62i0.16275

Menge, B. A., & Menge, D. N. (2013). Dynamics of coastal meta-ecosystems: the intermittent upwelling hypothesis and a test in rocky intertidal regions. Ecological Monographs, 83(3), 283-310.

Morgan, S. G., & Fisher, J. L. (2010). Larval behavior regulates nearshore retention and offshore migration in an upwelling shadow and along the open coast. Marine Ecology Progress Series, 404, 109-126.

Ottersen, G., Kim, S., Huse, G., Polovina, J. J., & Stenseth, N. C. (2010). Major pathways by which climate may force marine fish populations. Journal of Marine Systems, 79(3-4), 343-360.

Rasmuson, L. K., Blume, M. T., & Rankin, P. S. (2021). Habitat use and activity patterns of female deacon rockfish (Sebastes diaconus) at seasonal scales and in response to episodic hypoxia. Environmental Biology of Fishes, 104(5), 535-553.

Richardson, L. E., Graham, N. A., Pratchett, M. S., & Hoey, A. S. (2017). Structural complexity mediates functional structure of reef fish assemblages among coral habitats. Environmental Biology of Fishes, 100(3), 193-207.

Ryan, J. P., Fischer, A. M., Kudela, R. M., McManus, M. A., Myers, J. S., Paduan, J. D., … & Zhang, Y. (2010). Recurrent frontal slicks of a coastal ocean upwelling shadow. Journal of Geophysical Research: Oceans, 115(C12).

Shanks, A. L., McCulloch, A., & Miller, J. (2003). Topographically generated fronts, very nearshore oceanography and the distribution of larval invertebrates and holoplankters. Journal of Plankton Research, 25(10), 1251-1277.

Shanks, A. L., & Shearman, R. K. (2009). Paradigm lost? Cross-shelf distributions of intertidal invertebrate larvae are unaffected by upwelling or downwelling. Marine Ecology Progress Series, 385, 189-204.

Shanks, A. L., Morgan, S. G., MacMahan, J., & Reniers, A. J. (2010). Surf zone physical and morphological regime as determinants of temporal and spatial variation in larval recruitment. Journal of Experimental Marine Biology and Ecology, 392(1-2), 140-150.

Toohey, B. D., Kendrick, G. A., & Harvey, E. S. (2007). Disturbance and reef topography maintain high local diversity in Ecklonia radiata kelp forests. Oikos, 116(10), 1618-1630.

Trebilco, R., Dulvy, N. K., Stewart, H., & Salomon, A. K. (2015). The role of habitat complexity in shaping the size structure of a temperate reef fish community. Marine Ecology Progress Series, 532, 197-211.

Woodson, C. B., Eerkes-Medrano, D. I., Flores-Morales, A., Foley, M. M., Henkel, S. K., Hessing-Lewis, M., … & Washburn, L. (2007). Local diurnal upwelling driven by sea breezes in northern Monterey Bay. Continental Shelf Research, 27(18), 2289-2302.

Imogen Lucciano, Graduate student, OSU Department of Fisheries, Wildlife, & Conservation Sciences, Geospatial Ecology of Marine Megafauna Lab.

One year ago, I packed up my 11-year-old daughter, Mavis (for the purposes of this blog, I’ll refer to her as “my sidekick”), our two dogs, and all our books and we moved to Oregon. I was thrilled to arrive and begin my graduate studies in cetacean ecology and bioacoutics with the GEMM lab and the Marine Mammal Institute. It has not been an easy set of tasks to achieve high standards in graduate school while maintaining a constant presence as a single mother, but I am honestly having the time of my life. I am involved in an amazing graduate program and I get to do it with my sidekick cheering me on and making my life feel very whole. This is why I am excited to write this blog reporting on the progression of my thesis and the incredible animals that I have the pleasure of studying: the fin whale.  

Fin whales (Balaenoptera physalus) are the second largest cetacean on the planet and are present in nearly all temperate and polar oceanic regions of the world (1). For my master’s thesis, I will focus solely on the fin whales within a detectable range of our team’s research area off the Oregon coast. In the Northern Hemisphere, fin whales are known to grow up to 23 meters in length and weigh up to 40-50 metric tons (2). They have a slender profile and can be further identified by their hook-shaped dorsal fin in addition to a V-shape on their back referred to as a “chevron” (Fig. 1). Fin whales are a baleen whale in the rorqual family, which have adapted lunge feeding as their primary foraging method (3). This species of whales is also classified as endangered (1), making them a key focal species for research in our modern times of shifting conditions in ocean environments.

Although I am working to correlate the acoustic detections of fin whales across space and time with environmental drivers (like temperature and chlorophyll concentration), as an aspiring cetacean bioacoustician, one of my other burning related questions is: How can fin whale vocalizations be utilized to differentiate populations across the oceans? Perhaps my analysis of fin whales off the Oregon coast can contribute to the pool of researchers studying this species worldwide to help understand drivers of fin whale vocalization variability.

Fin whales can travel great distances, yet their unique vocal renditions of repetitive pulse calls at either a 20 Hz or 40 Hz frequency have geographic patterns (4). These renditions are stereotyped by inter-pulse interval (IPI), which is the rate at which the pulses are detected (5). What’s even more interesting is that unlike many other large baleen whale species, there is little evidence of seasonal behavior and vocalization patterns (5) (Figs. 2 & 3). This suggests that fin whales might not make repetitive annual migrations to accommodate foraging and reproduction. Are these animals prey driven with exemplary senses for finding prey over incredibly large distances in the ocean? Are fin whales consistently present off the Oregon coast? What are their names? Bob, Lucinda, Frederick? There is much to ponder here.

This past summer the Holistic Assessment of Living marine resources off Oregon (HALO) team recovered its first six months of continuously collected acoustic data from three hydrophones moored at designated source locations off the Newport coast. Around the same time, I transplanted my sidekick and myself in Ithaca, New York for the summer, so I could spend my summer days learning to identify and log baleen whale calls among other acousticians at the K. Lisa Yang Center for Conservation Bioacoustics at Cornell University. This work would contribute to my preparation for the analysis of the HALO acoustic data.

I was less than a month into this work when my sidekick ended up spending an entire week with us in the lab because the counselors at her summer camp all caught COVID-19. My sidekick is a dedicated book worm and had no problem keeping herself busy while we all worked, however, she is young and vivacious and so she would often share her music and jokes with the group. I recall (with an uncontrollable smirk on my face) one of her songs called the “Oof” song (Video 1), that is literally a repetitive beat with the onomatopoeia, “oof” being played over and over again. When it started playing I looked up from my computer to see a row of researchers sitting next to Mavis all bobbing their heads to the repetitive tone of “oof”, a tone that hilariously reminded us of a sped-up version of the repetitive pulse of fin whale song. From that point on, “oof” has involuntarily become a part of our language among this group of acousticians.

The summer blazed by, Fall is here, and my sidekick and I are back in Oregon. I am in the process of organizing our collected HALO data to accommodate analysis of baleen whales, including fin whales. At this point I am already able to see fin whale calls in our data (Fig. 4). Subsequently, I will spend the next few months analyzing these data to determine the patterns of fin whale calls over time at our three observation sites (on the shelf, the shelf edge, and off the shelf). Within this analysis I will also look to define the vocal repertoire of fin whales over our six-month study period, which will allow me to report on the frequency where they are primarily detected and the IPI with which the pulses occur.

Moving forward, the HALO team will continuously retrieve and replace the three hydrophones to collect our acoustic data, returning a rich long-term dataset of the study area. I am eager to learn whether the fin whale IPI will remain the same in this location or show changes according to shifts in upwelling or seasonally, assuming they remain in the Northern California Current and do not migrate away. I will continue to assess the acoustic patterns of fin whales over the next year to describe their distribution patterns. All the while with the “oof” song stuck in my head and with my vivacious book worm head banging in the background.

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References

(1) Fin Whale. NOAA Fisheries. https://www.fisheries.noaa.gov/species/fin-whale.

(2) Aguilar, A. & Garcia-Vernet, R. 2018. Encyclopedia of Marine Mammals, Third Edition: Fin Whale, Balaenoptera physalus, Pg 369-371. Academic Press, ISBN 978-0-12-804327-1.

(3) Shadwick, R. et al. 2019. Lunge feeding in rorqual whales. Physiology, 34: 409-418. https://journals.physiology.org/doi/epdf/10.1152/physiol.00010.2019.  

(4) Oleson, E. et al. 2014. Synchronous seasonal change in fin whale song in the North Pacific. Plos ONE, 9 (12). https://doi.org/10.1371/journal.pone.0115678.

(5) Morano, J. et al. 2012. Seasonal and geographical patterns of fin whale song in the western North Atlantic Ocean. The Journal of the Acoustical Society of America, 132 (1207): 1207-1212. https://doi.org/10.1121/1.4730890.

(6) Helble, T. et al. 2020. Fin whale song patterns shift over time in the central North Pacific. Frontiers of Marine Science, 2 (Marine Megafauna). https://doi.org/10.3389/fmars.2020.587110.  

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