Month: December 2018

GEMM Lab 2018: A Year in the Life

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

As 2018 draws to a close, it is gratifying to step back and appreciate the accomplishments of the past year. For all members of the GEMM Lab, 2018 has certainly been one for the books! Here are some of our highlights for your holiday enjoyment.

We conducted fieldwork to collect new data in multiple seasons, multiple hemispheres, and across oceans. For the first time, GEMM Lab members joined the Northern California Current Ecosystem cruises aboard NOAA ship Bell M. Shimada as marine mammal observers—Florence in February, Alexa in May, and me in September.

Dawn Barlow scans for marine mammals from the flying bridge of NOAA ship Bell M. Shimada. Photo: Jess O’Loughlin.
Alexa on-effort using binoculars to estimate the distance and bearing of a marine mammal sighted off the starboard bow. Image source: Alexa K.
An image of the NOAA ship Bell M. Shimada transiting between stations. Multiple members of the GEMM Lab conducted surveys from this NOAA vessel in 2018. (Image source: Alexa Kownacki)
Common dolphins (Delphinus delphis). Photo: Dawn Barlow.

Summertime in the Pacific Northwest brings the gray whales to the Oregon Coast. The drone-flying, poop-scooping, plankton-trapping team of Leigh, Todd, Leila, Joe, and Sharon took to the water for the third year to investigate the health of this gray whale population. It was a successful field season, ending with 72 fecal samples collected! Visiting students joined our experienced members to shadow the gray whale fieldwork—Julia Stepanuk and Alejandro Fernandez Ajo came from across the country to hop on board with us for a bit. Friendship and collaboration were built quickly in a little boat chasing after whale poop, bonding over peanut butter and jelly sandwiches.

Launching the drone. Photo by Alejandro Fernandez Ajo.
The gray whale team aboard R/V Ruby. Photo by Alejandro Fernandez Ajo.
Gray whale photo-identification. Photo by Dawn Barlow.

Another GEMM Lab team tracked the gray whales from the cliff in Port Orford. Lisa Hildebrand joined us as the GEMM Lab’s newest graduate student, and immediately led a team of interns on Oregon’s southern coast to track gray whale movements and sample their prey from a trusty research kayak.

The summer 2018 gray whale foraging ecology team, affectionately known as “team whale storm”, at the Port Orford Field Station.

Rachael observed seabirds from Yaquina Head in May and June, where the colony of common murres had the highest reproductive success in 10 years! Then she left the summertime in July to travel to the other end of the world, braving winter in the remote South Atlantic to study South American fur seals in the Falkland Islands.

Dr. Rachael Orben and Dr. Alistair Bayliss looking out towards the fur seals. Photo: Kayleigh Jones

In New Caledonia, Solene and a research team ventured to Antigonia Seamount and Orne Bank to study the use of these offshore areas by breeding humpback whales. They collected numerous biopsy samples and successfully deployed satellite tags. Solene was also selected to receive the Louis Herman research scholarship to continue studying humpback whale movement and diving behavior around seamounts.

Sorting biopsy samples during a successful expedition to study humpback whales around remote seamounts in the South Pacific.

Beyond fieldwork, our members have been busily disseminating our findings. In July, Leigh and I traveled to Wellington to present our latest findings on New Zealand blue whales to scientists, managers, politicians, industry representatives, and advocacy groups. Because of our documentation of a unique New Zealand blue whale population, which was published earlier this year, the New Zealand government has proposed to create a Marine Mammal Sanctuary for the protection of blue whales. This is quite a feat, considering blue whales were classified as only “migrant” in New Zealand waters prior to our work. Fueled by flat whites in wintery Wellington, we navigated government buildings, discussing blue whale distribution patterns, overlap with the oil and gas industry, what we now know based on our latest analyses, and what we consider to be the most pressing gaps in our knowledge.

Dr. Leigh Torres and Dawn Barlow in front of Parliament in Wellington, New Zealand following the presentation of their recent findings.

Alexa spent the summer and fall in San Diego, where she collaborated with researchers at NOAA Southwest Fisheries Science Center on her study of about the health of bottlenose dolphins off the California coast. Her time down south has been productive and we look forward to having her back in Oregon with us to round out the second year of her PhD program.

In the fall, Dom and Leigh participated in the first ever Oregon Sea Otter Status of Knowledge Symposium. With growing interest in a potential sea otter reintroduction, the symposium brought together a range of experts – including scientists, managers, and tribes – to discuss what we currently know about sea otters in other regions and how this knowledge could be applied to an Oregon reintroduction effort. Dom was one of many speakers at this event, and gave a well-received talk on Oregon’s previous sea otter reintroduction attempt and brief discussion on his thesis research. Over the next year, Dom not only plans to finish his thesis, but also to join an interdisciplinary research team to further investigate other social, genetic, and ecological implications of a potential sea otter reintroduction.

Sea otter mom and pup. Source: Hakai Magazine.
2018-19 OSU NRT Cohort. Source: Oregon State University.

Several GEMM Lab members reached academic milestones this year. Rachael was promoted to Assistant Professor in the spring! She now leads the Seabird Oceanography Lab, and remains involved in multiple projects studying seabirds and pinnipeds all over the world. Leila passed her PhD qualifying exams and advanced to candidacy in the spring, a major accomplishment toward completing her doctoral degree. I successfully defended my MS degree in June, and my photo was added to our wall gallery of GEMM Lab graduates. I won’t be leaving the GEMM Lab anytime soon, however, as I will be continuing my research on New Zealand blue whales as a PhD student. The GEMM Lab welcomed a new MS student in the summer—Lisa Hildebrand will be studying gray whale foraging ecology on the Oregon Coast. Welcome, Lisa! In early December, Solene successfully defended her PhD, officially becoming Dr. Derville. Congratulations to all on these milestones, and congratulations to Leigh for continuing to grow such a successful lab and guiding us all toward these accomplishments.

Dawn Barlow answers questions during her M.Sc. defense seminar.
Dr. Solene Derville and co-supervisors Dr. Claire Garrigue and Dr. Leigh Torres after a successful PhD Defense!

Perhaps you’re looking to do some reading over the holidays? The GEMM Lab has been publishing up a storm this year! The bulletin board outside our lab is overflowing with new papers. Summarizing our work and sharing our findings with the scientific community is a critical piece of what we do. The 21 new publications this year in 14 scientific journals include contributions from Leigh (13), Rachael (3), Solene (3), Leila (6), Florence (1), Amanda (1), Erin (1), Courtney (1), Theresa (1), and myself (3). Scroll down to the end of this post to see the complete list!

If you are reading this, thank you for your support of our lab, our members, and our work. Our successes come not only from our individual determination, but more importantly from our support of one another and the support of our communities. We look forward to what’s ahead in 2019. Happy holidays from the GEMM Lab!

The whole GEMM Lab (lab dogs included) gathered for an evening playing “Evolution” at Leigh’s house.

Barlow, D. R., Torres, L. G., Hodge, K. B., Steel, D., Baker, C. S., Chandler, T. E., Bott, N., Constantine, R., Double, M. C., Gill, P., Glasgow, D., Hamner, R. M., Lilley, C., Ogle, M., Olson, P. A., Peters, C., Stockin, K. A., Tessaglia-Hymes, C. T., & Klinck, H. (2018). Documentation of a New Zealand blue whale population based on multiple lines of evidence. Endangered Species Research, 36, 27-40.

Barlow, D. R., Fournet, M., & Sharpe, F. (2018). Incorporating tides into the acoustic ecology of humpback whales. Marine Mammal Science.

Baylis, A. M., Tierney, M., Orben, R. A., Staniland, I. J., & Brickle, P. (2018). Geographic variation in the foraging behaviour of South American fur seals. Marine Ecology Progress Series, 596, 233-245.

Bishop, A., Brown, C., Rehberg, M., Torres, L., & Horning, M. (2018). Juvenile Steller sea lion (Eumetopias jubatus) utilization distributions in the Gulf of Alaska. Movement ecology, 6(1), 6.

Burnett, J. D., Lemos, L., Barlow, D., Wing, M. G., Chandler, T., & Torres, L. G. (2018). Estimating morphometric attributes of baleen whales with photogrammetry from small UASs: A case study with blue and gray whales. Marine Mammal Science.

Cardoso, M. D., Lemos, L. S., Roges, E. M., de Moura, J. F., Tavares, D. C., Matias, C. A. R., … & Siciliano, S. (2018). A comprehensive survey of Aeromonas sp. and Vibrio sp. in seabirds from southeastern Brazil: outcomes for public health. Journal of applied microbiology, 124(5), 1283-1293.

Derville, S., Torres, L. G., Iovan, C., & Garrigue, C. (2018). Finding the right fit: Comparative cetacean distribution models using multiple data sources and statistical approaches. Diversity and Distributions, 24(11), 1657-1673.

Derville, S., Torres, L. G., & Garrigue, C. (2018). Social segregation of humpback whales in contrasted coastal and oceanic breeding habitats. Journal of Mammalogy, 99(1), 41-54.

Hann, C. H., Stelle, L. L., Szabo, A., & Torres, L. G. (2018). Obstacles and Opportunities of Using a Mobile App for Marine Mammal Research. ISPRS International Journal of Geo-Information, 7(5), 169.

Holdman, A. K., Haxel, J. H., Klinck, H., & Torres, L. G. (2018). Acoustic monitoring reveals the times and tides of harbor porpoise (Phocoena phocoena) distribution off central Oregon, USA. Marine Mammal Science.

Kirchner, T., Wiley, D. N., Hazen, E. L., Parks, S. E., Torres, L. G., & Friedlaender, A. S. (2018). Hierarchical foraging movement of humpback whales relative to the structure of their prey. Marine Ecology Progress Series, 607, 237-250.

Moura, J. F., Tavares, D. C., Lemos, L. S., Acevedo-Trejos, E., Saint’Pierre, T. D., Siciliano, S., & Merico, A. (2018). Interspecific variation of essential and non-essential trace elements in sympatric seabirds. Environmental pollution, 242, 470-479.

Moura, J. F., Tavares, D. C., Lemos, L. S., Silveira, V. V. B., Siciliano, S., & Hauser-Davis, R. A. (2018). Variation in mercury concentration in juvenile Magellanic penguins during their migration path along the Southwest Atlantic Ocean. Environmental Pollution, 238, 397-403.

Orben, R. A., Kokubun, N., Fleishman, A. B., Will, A. P., Yamamoto, T., Shaffer, S. A., Takahashi, A., & Kitaysky, A. S. (2018). Persistent annual migration patterns of a specialist seabird. Marine Ecology Progress Series, 593, 231-245.

Orben, R. A., Connor, A. J., Suryan, R. M., Ozaki, K., Sato, F., & Deguchi, T. (2018). Ontogenetic changes in at-sea distributions of immature short-tailed albatrosses Phoebastria albatrus. Endangered Species Research, 35, 23-37.

Pickett, E. P., Fraser, W. R., Patterson‐Fraser, D. L., Cimino, M. A., Torres, L. G., & Friedlaender, A. S. (2018). Spatial niche partitioning may promote coexistence of Pygoscelis penguins as climate‐induced sympatry occurs. Ecology and Evolution, 8(19), 9764-9778.

Siciliano, S., Moura, J. F., Tavares, D. C., Kehrig, H. A., Hauser-Davis, R. A., Moreira, I., Lavandier, R., Lemos, L. S., & Quinete, N. S. (2018). Legacy Contamination in Estuarine Dolphin Species From the South American Coast. In Marine Mammal Ecotoxicology (pp. 95-116). Academic Press.

Sullivan, F. A., & Torres, L. G. (2018). Assessment of vessel disturbance to gray whales to inform sustainable ecotourism. The Journal of Wildlife Management, 82(5), 896-905.

Sztukowski, L. A., Cotton, P. A., Weimerskirch, H., Thompson, D. R., Torres, L. G., Sagar, P. M., Knights, A. M., Fayet, A. L., & Votier, S. C. (2018). Sex differences in individual foraging site fidelity of Campbell albatross. Marine Ecology Progress Series, 601, 227-238.

Torres, L. G., Nieukirk, S. L., Lemos, L., & Chandler, T. E. (2018). Drone up! Quantifying whale behavior from a new perspective improves observational capacity. Frontiers in Marine Science, 5.

Yates, K. L., Bouchet, P. J., Caley, M. J., Mengersen, K., Randin, C. F., Parnell, S., … & Sequeira, A. M. M. (2018). Outstanding challenges in the transferability of ecological models. Trends in ecology & evolution.

 

Inter- and Transdisciplinary Sea Otter Research

By Dominique Kone, Masters Student, Marine Resource Management

As the human population continues to grow, so does our impact on marine environments. In many cases, these problems – such as microplastics, vessel noise, or depleted fisheries – are far too grand for any one person to tackle on their own and it takes a team effort to find adequate solutions. Experts within a single field (e.g. ecology, economics, genetics) have been collaborating to tackle these issues for decades, but there is an increasing interest and recognition of the importance in working with others outside one’s own discipline.

It’s not surprising that most collaborative efforts are between experts from the same field. It’s easier to converse with those with similar vocabulary, we often enjoy learning from our peers, and our thought-processes and problem-solving skills are typically very similar. However, as issues become more complex and stretch across disciplines, the need for interdisciplinary collaboration becomes more and more imperative. As a graduate student studying marine resource management, I’ve learned the great value in conducting interdisciplinary work. Yet, I still have much to learn if I want to continue to help find solutions to the many complex marine issues. Therefore, over the next year, I’ve committed to joining a interdisciplinary team of graduate students, as part of an NSF-funded fellowship program at Oregon State University (OSU), to further investigate a potential sea otter reintroduction to Oregon. Here, I provide a brief overview of the program and my team’s goals for the coming year.

Source: Hakai Magazine.

The fellowship program emphasizes both interdisciplinary and transdisciplinary approaches, so before I explain the program, it’s important to first understand these terms. In short, interdisciplinarity typically relates to experts from different fields analyzing, synthesizing, and coordinating their work as a whole (Choi & Pak 2006). Another way to think about this, in more practical terms, is if two or more experts share information and learn from one another; each expert can then individually apply that information or lessons-learned to their own line of work. In contrast, transdisciplinary work is slightly more collaborative, where experts work more hand-in-hand to develop a product or solution that transcends their disciplines’ traditional boundaries. The experts essentially create a product that would not have been possible working in isolation. In practice, the product(s) that stems from inter- and transdisciplinary work – if they truly are inter- or transdisciplinary by definition – is potentially very different.

Source: Dr. Shoshanah Jacobs.

With an increasing interest in interdisciplinary work, the National Science Foundation (NSF) developed the National Research Traineeship (NRT) program to encourage select universities to develop and implement innovative and transformative models for training graduate students in STEM disciplines. After soliciting proposals, the NSF awarded OSU one of these NRT projects to support OSU’s Risk and Uncertainty Quantification in Marine Science NRT Program. OSU’s NRT program was born out of the recognition that much of the complexity of marine issues is largely due to the uncertainty of natural and human systems. Therefore, the primary purpose of this program is to train the next generation of natural resource scientists and managers to be better equipped to study and manage complex marine systems, especially under extreme uncertainty and potential risk.

Source: Oregon State University.

This NRT program trains graduate students in three core concept areas: coupled natural human systems, big data, and risk and uncertainty analyses and communications. To learn these core concepts, students fulfil a minor that includes coursework in statistical inference, uncertainty quantification, risk analyses, earth system science, and social systems. In addition to the minor, students also conduct collaborative research in small (3-5 students) cross-disciplinary teams to address specific issues in marine resource management. Within each team, students come from different disciplines and fields, and must learn to work together to produce a transdisciplinary research product. Throughout the year, each team will develop a set of research questions to address their issue at hand, conduct research which links all their fields, and produce a transdisciplinary report summarizing the process they undertook and the end product. Most students who are accepted into the NRT program are awarded one-year fellowships, funded by the NSF.

At the start of this academic year, I was awarded one of these NRT fellowships to address the many issues and implications of a potential sea otter reintroduction to Oregon. Over the next year, I will be working with two other OSU graduate students with backgrounds in genetics and social sciences. Our task is to not only investigate the ecological implications – which I am currently doing for my own thesis – but we are to expand this investigation to also address many of the genetic, political, and social factors, as well. While each of us is capable of addressing one of these factors individually, the real test will be in finding linkages between each of our disciplines to make this project truly transdisciplinary.

Structure and vision of OSU’s NRT program. Source: Oregon State University.

Since our project started, we have worked to better understand each another’s expertise, interests, and the general need for a transdisciplinary project of this sort. After acquiring this base understanding, we spent a considerable amount of time developing research questions and potential methods for addressing our issue. Throughout this process, it’s already become apparent that each of us is starting to learn important teamwork and collaboration skills, including effective communication and explanation of complicated concepts, active listening, critical thinking, and constructive feedback.  While these skills are imperative for our research over the next year, they are also life-long skills that we’ll continue to use in our careers beyond graduate school.

As I’ve stated previously, learning to be an effective collaborator is extremely important to me. Getting the opportunity to work interdisciplinarily is what attracted me to my thesis, the marine resource management program, and the NRT program. By choosing to take my graduate education down this path, I’ve been fortunate to obtain important skills in collaboration, as well as work on a project that allows me to tackle real-world issues and creatively develop scientifically-based solutions. I have high hopes for this NRT project, and I’m excited to continue to conduct meaningful and targeted research over the next year with my new team.

2018-19 OSU NRT Cohort. Source: Oregon State University.

References:

Choi, B. C., and A. W. Pak. Multidisciplinarity, interdisciplinarity and transdisciplinarity in health research, service, education and policy: 1. Definitions, objectives, and evidence of effectiveness. Clinical and Investigative Medicine. 29(6): 351-64.

Moving from overlap to interaction in seabird-fishery analysis

By Dr. Leigh Torres, Director of the GEMM Lab

In our modern world we often share space with people, but never really interact with them. Like right now, I am on a train in France with a bunch of people but I’m not interacting with any of them (maybe because I don’t speak French…). This situation extends to our efforts to understand the bycatch of marine predators in fisheries.

Productivity in the ocean is patchy, so both fishing vessels and marine predators, like seabirds and dolphins, may target the same areas to get their prey. This scenario can be considered spatial overlap, but not necessarily interaction because the two entities (predator and vessel) can independently chose to be in the same place at the same time. Also, overlap can happen at larger spatial and temporal scales than interaction events, which typically must occur at small scales. Again, consider me on this train: all my fellow passengers and I are overlapping on a 500 m long train for 2.5 hours (larger scale) but I only interact with the passenger in the seat 1 m across from me for a minute (smaller scale) while I explain that I don’t understand what they are saying.

Distinguishing overlap from interaction between seabirds and fishing vessels is important to help managers determine how to best direct their efforts to reduce bycatch. Different management approaches can be applied depending on whether seabirds are using the same habitat as fishing vessels (overlap) or are attracted to vessels for feeding opportunities (interaction) and then incidentally caught/injured in the fishing gear. Furthermore, if we can describe discrete interaction events we may also be able to identify the individual fishing vessel, fishing gear used, country of origin, and other such specific information that can help direct bycatch reduction efforts.

However, studying the spatial and temporal relationships between seabirds and fishing vessels is challenging, and highly dependent on the quality of data we have, or can collect, about the movements of birds and boats at-sea. Tracking the movements of seabirds has evolved rapidly with the development of tagging technology and miniaturization, so that over the past 10 years seabird ecologists have collected a large amount of high-resolution GPS data of seabird foraging. While these data reveal fascinating patterns of seabird ecology, our ability to relate these seabird distribution data to fishing vessels has remained limited due to limited access to fishing vessel location data. Historically, fishermen have not wanted to divulge their fishing locations for fear of losing their ‘secret sweet spot’ or regulatory infractions. So, where fishing vessels fish has often been a mystery, at least fine scales. For a long time fishing effort data was only released at scales of 5 x 5 degree grid cells and monthly scales (Fig. 1) (Phillips et al. 2006), which is only broadly useful for assessment of overlap and not useful for assessing interaction events. The situation has improved in some countries where Vessel Monitoring Systems (VMS) data are available but even these GPS data are often too coarse to reveal interaction events (although it’s much better than what was previously available!). In fact, I wrote a paper about this topic in 2013 called “Scaling down the analysis of seabird-fisheries analysis” that called for higher resolution vessel position data to better evaluate and manage seabird and fishing vessel interactions (Torres et al. 2013).

Figure 1. Taken from Phillips et al 2006, this example shows overlap between fishing effort and seabird distribution at a large-scale.

Progress was made in 2016 with the release of Global Fishing Watch (globalfishingwatch.org) that has significantly increased transparency in the fishing industry and revolutionized our ability to monitor fishing vessel activities (Robards et al. 2016). Almost every fishing vessel in the world is required to use the Automated Identification System (AIS) that pings GPS quality position data to satellite and shore receiving stations around the world. AIS was originally developed to increase maritime safety by reducing collision risk, but Global Fishing Watch has developed methods to acquire these AIS data globally, distinguish fishing vessels (from cargo ships or sailing vessels), classify fishing vessels by fishing method, and disseminate these data in an accessible and visually understandable able format (de Souza et al. 2016; Kroodsma et al. 2018). When I saw the Global Fishing Watch website for the first time I actually let out a ‘Woohoo!’ because I knew this was the missing piece I needed to move from overlap to interaction.

So, I assembled a great team of collaborators including Dr. Rachael Orben – seabird movement ecologist extraordinaire – and colleagues who have collected GPS tracking data from three species of albatross in the North Pacific Ocean. Another important step was acquiring funding to support the research effort from the NOAA Bycatch Reduction Engineering Program, and to establish a collaboration with Global Fishing Watch.  Fast forward a year and through many data analysis and R coding puzzles, and we have made the jump from overlap to interaction, with some preliminary results to share.

We compiled GPS tracks representing foraging trips conducted by Laysan (Phoebastria immutabilis) and black-footed (P. nigripes) albatrosses breeding in the Hawaiian islands, and juvenile short-tailed albatross (P. albatrus) from Japan. First we identified overlap between bird and boat at daily and 80 km scales. Next, we quantified encounter events at scales of 10 minutes and between 30 and 3 km, which was the assumed distance at which birds are able to perceive a boat. Finally, interaction events were identified when birds and boats were within 3 km and 10 minutes of each other.

At an absolute level, short-tailed albatross overlapped, encountered and interacted with many more fishing vessels than black-footed and Laysan albatross. However, it is important to point out that these results may be biased by the temporal sampling resolution of the GPS tracking data (how often a location was recorded), which we have not accounted for yet. Nevertheless, what is interesting is that when the percent of interaction events that derived from encounter events is assessed, black-footed and Laysan albatross demonstrate much higher rates of fisheries interactions. These results indicate that when a black-footed albatross encountered a fishing vessel engaged in fishing, nearly 50% of these opportunities turned into an interaction event. This rate was 39 and 26 percent for Laysan and short-tailed albatross respectively. This species-level difference between absolute and relative (percentage) interaction with fisheries may be due to the overall distribution patterns of the different albatross species, with short-tailed albatross using areas that overlap with fishing activity more frequently (coastal margins). Furthermore, these results indicate that short-tailed albatross may be more ‘vessel-shy’ than black-footed and Laysan albatross. The high black-footed albatross percent interaction rate aligns with the high by-catch rate of this species, and emphasizes the need to better understand and manage their interactions with fishing vessels.

While these results from our novel analysis are an interesting start to helping inform bycatch mitigation efforts, perhaps the most illustrative (and coolest!) output so far are the below animations that show the fine-scale movement tracks of an albatross and fishing vessel (Fig. 2 and 3). Both animations are a 24 hour period and show an albatross (red dot) and a fishing vessel (yellow dot). But, Figure 2 illustrates an overlap event, where the bird and boat clearly overlap spatially and temporally but do not interact. However, in Figure 3 we see how the albatross flies directly to the vessel and the bird and vessel remain spatially and temporally linked, demonstrating an interaction event. Our next steps are to improve our ability to distinguish these interaction events (assessment of duration and trajectory correspondence) and to describe the driving factors (e.g., albatross species, fishing vessel method and flag nation, environmental variables) that lead an albatross to move from overlap to interaction.

Figure 2. Fine-scale animation of overlap between the movement path of a Laysan albatross GPS track and the AIS track of a fishing vessel, overlaid on bathymetry. While the bird and boat overlap at this scale, the animation illustrates how the bird and boat do not interact with each other.

 

Figure 3. Fine-scale animation of overlap between the movement path of a Laysan albatross GPS track and the AIS track of a fishing vessel, overlaid on bathymetry. This animation illustrates how the bird and boat act independently at the start, and then the bird travels directly to the vessel’s location and the movements of the two entities corresponded spatially and temporally, demonstrating a clear interaction event.

 

 

References

de Souza, Erico N., Kristina Boerder, Stan Matwin, and Boris Worm. 2016. ‘Improving Fishing Pattern Detection from Satellite AIS Using Data Mining and Machine Learning’, PLoS ONE, 11: e0158248.

Kroodsma, David A., Juan Mayorga, Timothy Hochberg, Nathan A. Miller, Kristina Boerder, Francesco Ferretti, Alex Wilson, Bjorn Bergman, Timothy D. White, Barbara A. Block, Paul Woods, Brian Sullivan, Christopher Costello, and Boris Worm. 2018. ‘Tracking the global footprint of fisheries’, Science, 359: 904-08.

Phillips, R. A., J. R. D. Silk, J. P. Croxall, and V. Afanasyev. 2006. ‘Year-round distribution of white-chinned petrels from South Georgia: Relationships with oceanography and fisheries’, Biological Conservation, 129: 336-47.

Robards, MD, GK Silber, JD Adams, J Arroyo, D Lorenzini, K Schwehr, and J Amos. 2016. ‘Conservation science and policy applications of the marine vessel Automatic Identification System (AIS)—a review’, Bulletin of Marine Science, 92: 75-103.

Torres, Leigh G., P. M. Sagar, D. R. Thompson, and R. A. Phillips. 2013. ‘Scaling-down the analysis of seabird-fishery interactions’, Marine Ecology Progress Series, 473.

 

 

Who Am I? Exploring the theory of individualisation among marine mammals

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

“Just be yourself!” is a phrase that everyone has probably heard at least once in their lives. The idea of being an individual who is distinctly different from other individuals is a concept that is focal to the society we live in today. While historically it may have been frowned upon to be the “black sheep in the crowd”, nowadays that seems to be the goal.

Source: Go Comics.

This quest for uniqueness has resulted in different styles of fashion, speech, profession, interest in art, music, literature, automobile types – the list is endless. The American Psychological Association defines personality as the “individual differences in characteristic patterns of thinking, feeling and behaving”1. So, all of the choices we make on a daily basis shape our behaviour, and our behaviour in turn shapes our personality.

Since personality is something that is so engrained within human society, it isn’t surprising that ecologists have explored this concept among non-humans. Decades of research have resulted in an abundance of literature detailing personality in many different taxa and species, ranging from chimpanzees to mice to ants2. Naturally, the definition of personality for animals differs from that for humans since the assessment of animal thoughts and feelings is still somewhat of a locked box to us. Nevertheless, the behavioural aspect of the two definitions remains consistent whereby animal personality is broadly defined as “consistent variation in behavioural traits between individuals”3.

Although I am an early career marine mammal ecologist finding my footing in this rapidly expanding field, I have a keen interest in teasing apart possible cases of individual specialisation within marine mammal populations. So, before getting straight into the nitty gritty of individual specialisation, it is important for me to take a small step back and consider the concept of specialisation as applied to small subgroups or populations of marine mammals.

Specialisations are mostly related to foraging or feeding behaviour whereby a subgroup of individuals will develop a novel method to locate and capture prey. These behaviours have been reported for several marine mammal species, and are strongly coupled to intra and inter-specific competition with other predators for prey and habitat characteristics. Furthermore, it is posited that factors such as resource benefits (e.g. energy content of prey), prey escape rates, and handling times can be minimised if specialisation for a particular prey type or habitat occurs4.

In Florida Bay, Torres & Read5 documented two distinct foraging strategies employed by two bottlenose dolphin ecotypes. One dolphin ecotype was found to forage using deep diving with erratic surfacings, whereas the second ecotype chose to forage through mud ring feeding and were mostly seen in shallow habitats. The latter ecotype is in fact so adapted to shallow depths that dolphins were typically observed foraging in waters <2 m deep. In this example, the foraging tactics of the two ecotypes are strongly driven by habitat conditions, specifically depth. The video below is aerial footage of bottlenose dolphins performing mud ring feeding.

Such group specialisations have been identified not only in several other bottlenose dolphin populations around the world6,7, but also in other cetacean species, including killer whales (distinct differences in target prey between transients and residents8), Guiana dolphins (mud-plume feeding9), humpback dolphins (strand feeding10), and several others. Noticeable here is that these records concern Odontocete species, which is not surprising since these toothed whales are vastly different to baleen whales in that they often live in structured groups with bonds between individuals sometimes lasting for decades11. Long-term relationships are conducive to developing specialised group hunting strategies as individuals will spend considerable time with one another and the success of obtaining prey depends on the cooperation and coordination of the group.

For baleen whales and other marine mammals, such as pinnipeds, where life history and social organisation is more geared toward a solitary life, examples of group specialisations are relatively rare (with the exception of the well-documented bubble-net feeding exhibited by humpback whales12). While group specialisation may not be as prevalent in Mysticetes, the same problems of inter and intra-specific competition persists among these more solitary species too, which would suggest that individuals should develop their own unique foraging tactics and preferences. Evidence for individualisation is hard to obtain since it requires repeated observations of the same individuals over time with good knowledge of the prey type being consumed and/or the habitat being used to forage in.

Nevertheless, examples do exist. Perhaps the most well-documented case of individualisation within a population for marine mammals is of the sea otter. Estes et al. (2003) describe 10 female sea otters in Monterey Bay that had high inter-individual variation in diet, which they investigated over a scale of 8 years13. Most females specialised on 1-4 types of prey, with marked differences between the diets chosen by each female, despite habitat overlap. This individualisation of diet was not attributable to variation in prey availability; hence, authors concluded that this extreme specialisation occurred to reduce intra-population competition for prey.

Ecologists have historically (and probably still to this day) disagreed on whether individualisation actually matters in the grand scheme of things. There are generally three schools of thought on the matter: (1) individual specialisation is rare and/or weakly influences population dynamics and so is not very important; (2) while individual specialisation does occur and may in fact be commonplace, it does not affect ecological processes at the large population scale; and (3) individual specialisation is widespread and can significantly impact population dynamics and/or ecosystem function.

As you might have guessed by this point, I find myself in the third school of thought. There are many arguments supporting this theory, and what I believe to be very good arguments against statements 1 and 2. While I have only provided one specific named example for individual specialisation in a marine mammal, there are several documented cases of such occurrences among other marine taxa (e.g., pinnipeds14, sharks15, fish16) and a much larger number of studies for terrestrial species4. Thus, the claim that it is rare or weak, seems implausible to me.

Statement 2 is a little more complicated to tackle as it involves understanding how actions on a relatively small scale affect a whole population or even an ecosystem. For instance, consider two female sea otters living in a small coastal area where one sea otter prefers to eat turban snails and the other exclusively feeds on abalone. The sudden decline in abundance of either of these prey could lead to serious health and reproductive issues for those females. Should the low prey abundance persist, then poor health and reproduction of several females in a population that specialise on that prey item can rapidly lead to genetic loss and an overall population decline. Particularly if an individual’s or species’ home range is rather restricted or small. In the case of the sea otter, which are often touted as a keystone species due to its presence preventing sea urchin barren formation that is known to wreak havoc on kelp forests, knock-on effects of such a population decline could result in poor overall ecosystem health.

It may be easy to assume that one individual dolphin, otter, seal or whale cannot possibly make a difference to a whole population or ecosystem. This assumption strikes me as a little odd since humans are always told to ‘be the change they wish to see in the world’ and that ‘every person can make a difference’. Why then should these sentiments not be applicable to non-humans? While a gray whale may not hold a sign at a protest or run for president (actions commonly considered to cause change in the human world), perhaps the choice that a gray whale makes every day to only consume one species of zooplankton, can influence other gray whales in the area, predators from other taxa, habitat structure, other prey availability, and/or cause trophic cascades.

Through my research, I aim to elucidate whether the gray whales display some level of foraging individualisation while feeding in Port Orford, Oregon. I will use data from four years to compare tracks of individual whales with zooplankton samples collected in the area to correlate each individual’s movement patterns with prey availability. I will assess the quality of prey through bomb calorimetry and microplastic analysis of the zooplankton samples to determine energetic content and pollutant levels, respectively. This prey assessment will describe the potential effects of prey specialization on whales, which is fundamental to assessing overall population health. Individualisation can strongly affect fitness of individuals, either positively or negatively depending on several factors, which will undoubtedly have an impact at the population level.

(The videos below are examples of two different tactics we see the gray whales display while foraging along the Oregon coast in the summer months. The first video shows a whale foraging among kelp with some very acrobatic moves, while the second is of a whale employing the ‘sharking’ method where the whale is feeding benthically in such shallow depths that both the pectoral fin and the fluke stick out of the water, making the whale look like a ‘shark’.)

References

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