Research

Education
I currently work with Dr. Erin Shortlidge’s Biology Education Research (BER) group at Portland State University (PSU) to assist with a project that supports urban Science, Technology, Engineering, and Mathematics (STEM) transfer students as they transition to PSU from local community colleges in Portland, OR. In this capacity, I have gained qualitative research skills by leading focus groups to better understand the impact that support programs have on student experiences, including the effects on sense of belonging, science identity, and science self-efficacy. My education research interests focus on three related themes:

1) Broadening participation and examining equity, inclusion, and diversity issues in undergraduate STEM education. Women, racial minorities, first generation, and low-income students are traditionally underrepresented in STEM disciplines. I am interested in assessing classroom performance disparities for these underrepresented groups and implementing interventions to help address these disparities. I am particularly interested in implementing equity programs and assessing the effectiveness of these programs.

2) Assessing if/how field-based learning experiences impact undergraduate student learning and persistence in STEM. There is something special about field research that helps garner interest in biology and other field-based science disciplines. I am interested in understanding the impact of these field learning experiences in motivating and retaining undergraduate students in science majors and in STEM careers after graduation.

3) Examining factors that affect undergraduate student success. STEM majors have substantially lower rates of retention than other disciplines. There are many reasons why students intending to pursue STEM degrees leave their majors, including an unwelcoming atmosphere in STEM courses, unengaging introductory courses, insufficient mathematical skills, and/or a lack of information on the types of careers available to them. I am interested in exploring the factors that contribute to STEM major attrition and implementing interventions to increase retention and improve student success. I recently conducted a project to assess the impact of offering a career exploration and professional development course to life science majors at Washington State University (WSU) in Vancouver, WA. Students reported that the course effectively broadened their understanding of career opportunities in the life sciences, and thus may be an effective means of improving retention of students in STEM majors and in STEM careers after graduation.

Ecology and Animal Behavior
My doctoral work focused on predator-prey interactions and social foraging behavior of marine mammals. I explored how oceanographic and environmental variability affected the distribution and behavior of mid-trophic level prey species, and ultimately the how the distribution and behavior of these prey species affected marine mammal behavior.

Digital Acoustic Recording tag (Dtag) deployed on a humpback whale. Photo: Ari Friedlaender, permit no. 14122

Marine predators are notoriously difficult to study due to the fact that they spend the majority of their lives underwater where they cannot be directly observed. Technological advances in biotelemetry (e.g., tags that enable us to record whale three-dimensional movements at fine scales), combined with traditional technologies, such as echosounders (fish finders used to map whale prey), have greatly facilitated studies of whale foraging behavior throughout the past decade. I used these technologies along with ecological theory, such as optimal foraging theory, to make predictions regarding how a predator will allocate its time and energy when foraging.

Deploying the echosounder

 

My work highlights the importance of predator-prey interactions in shaping animal behavior. Through spatial and temporal integration of whale fine-scale movements and prey distribution, I addressed questions regarding how prey characteristics (patch size, depth, density) affected whale feeding behavior. I have found that humpback whales foraging in Southeast Alaska targeted the densest region of the krill layer, maximizing their energetic gain by capturing the most prey with each lunge. My findings indicate the importance of considering prey density, when testing optimal foraging models for whale foraging behavior. In another similar study where a group of foraging whales fed on pre-spawning Pacific herring aggregations, I was able to address similar questions regarding characteristics of herring schools targeted by foraging humpback whales, how fish schools changed through time, and the relationship between herring school characteristics and whale group size. I found that herring schools targeted by humpbacks were dense and distributed near the bottom in relatively shallow water during daylight hours, and that the increasing predation pressure exerted by humpbacks whales through time influenced herring school behavior; herring moved closer to the bottom and their density decreased.

Group foraging humpback whales, photo: Ari Friedlaender, permit no. 14122

I also examined the social interactions driving group foraging in humpback whales. Group foraging, or social predation, can range from concurrent chases, where each animal independently attempts to pursue a prey, to coordinated hunts, where a team of individuals performs different complementary subtasks or roles in a division of labor. Within a division of labor, animals may specialize in roles, repeatedly performing the same subtasks, which can result in improved performance efficiency. Humpback whales often feed in large groups, where they coordinate movements in space and time, and use bubbles to herd prey together to make them easier to capture, a behavior termed bubble-net feeding. It had been proposed that a division of labor with role specialization exists in these bubble-net feeding groups, but without detailed subsurface monitoring of whale foraging behavior, the extent to which whales repeated specific behaviors remained unknown. With the aid of biologging technology, I was able to document the detailed subsurface movements of foraging whales, and found that group feeding humpback whales maintained specific behavioral patterns that they repeated across foraging events, suggesting that they were specializing in roles during a feeding bout. It is likely that this repetition of roles facilitates coordination of the group, ultimately improving feeding efficiency, and suggests that whales were cooperating using a division of labor. This work adds to the growing body of literature on cooperative hunting strategies in a variety of carnivores, birds, primates, and cetaceans.

Although my research has focused almost exclusively on marine systems, I have advised undergraduate student research projects on a wide-variety of topics in animal behavior, including studies of both aquatic and terrestrial systems. As an advisor, I aim to emphasize inquiry-driven research questions, where students generate their own testable hypotheses on topics of interest to them. I have found this to be an extremely effective way for students to understand the entire scientific process, taking ownership of the project because it was almost entirely their idea. Examples of projects in which I have advised students include: Female-female dominant and submissive interactions in Siamese fighting fish, sex-dependent foraging behavior in the large milkweed bug and its implications regarding reproductive fitness, the effect of feeder color and nectar content on the foraging behavior of Anna’s hummingbird, the effects of temperature variation on male guppy mating behaviors, bird vigilance while foraging in urban versus rural areas, deterrence of sea lion haul-out behavior using electrical devices, aggression in male versus female mallard ducks during the fall non-nesting season, behavioral differences of eastern grey squirrels in urban versus natural environments, effects of radio-frequency electromagnetic field on the foraging capabilities of red harvester ants, activity level of southern sea otters in anticipation of feeding, and earthworm response to vibrations that mimic predator and natural environmental vibrations.

Filter feeding humpback whale photo: Ari Friedlaender, permit No. 14122