ECR Spotlight is a series of interviews with early-career authors from a selection of papers published in Journal of Experimental Biology and aims to promote not only the diversity of early-career researchers (ECRs) working in experimental biology during our centenary year, but also the huge variety of animals and physiological systems that are essential for the ‘comparative’ approach. Yordano Jimenez and Kelsey Lucas are authors on ‘ Flexibility is a hidden axis of biomechanical diversity in fishes’, published in JEB. Yordano is a Postdoctoral Research Fellow in the lab of Eric Tytell at Tufts University, Medford, USA, investigating the comparative biomechanics of muscle. Kelsey is Assistant Professor in Biological Sciences, University of Calgary, Canada, investigating the ecological biomechanics of aquatic animals.

Kelsey Lucas and Yordano Jimenez

Describe your scientific journey and your current research focus

Yordano: Animals have always fascinated me with their quirky behavior and dynamic beauty. I particularly love biomechanics because it combines the exactitude of physics with the elegant messiness of living systems! My first exposure to the field was as an undergraduate at Northern Arizona University with Dr Alice Gibb, where we studied the escape behaviors of bottom-dwelling flatfish at Friday Harbor Labs in Washington state. I earned my PhD from Brown University in 2021 under the supervision of Dr Beth Brainerd, where I studied the functional modularity of muscles (i.e. how fish use their swimming muscles to suction feed). My postdoctoral work at Tufts University with Dr Eric Tytell, with collaborative work at Woods Hole Oceanographic Institute, focused on the muscle and body mechanics of swimming using a version of John Long's ‘fish bender’ alluded to in our Commentary. In the Fall, I will be starting my Comparative Biomechanics lab at Providence College, where I will expand my work on fish muscle to include other critters, such as snakes and lobsters, that also flex their bodies to move.

Kelsey: I've always been into both ecology and math/physics, and so I was excited to discover the field of biomechanics as an undergraduate at Roger Williams University, where I worked with Dr Sean Colin on feeding flows through jellyfish tentacle arrays and how that influences prey capture capabilities. During my graduate work at Harvard (MA advised by Dr George Lauder; PhD co-advised by Drs Peter Girguis and Eric Tytell), I investigated body flexibility and fluid dynamics of fish swimming. As a postdoc with Dr Karen Alofs at the University of Michigan, I returned to my ecological interests by integrating fish functional morphology, climate change physiology, and ecological modeling, to understand the factors influencing what habitats different fishes are found in. I'm continuing similar work in ‘ecological biomechanics’ at the University of Calgary.

How would you explain the main message of your Commentary to a member of the public?

Water is a very dense fluid, and that makes it energetically costly for animals to swim. How do animals of different shapes and movements solve the problem of generating flows that move them through water efficiently? We have a very good understanding of how stiff, man-made materials solve this problem, but we don't have as comprehensive an understanding for a fish, with its bendy body and fins. While we know that muscles, bones, skin and other tissues come together, create a bending body and manipulate fluid around the body to generate swimming forces, we're just beginning to fully understand how fish swim. Our paper illustrates the limitations of our knowledge and how we might use new technologies to move forward. We hope that pursuing this work further will help us understand the connections between form and function in fishes, the selective pressures that may have led to the diversity of fishes we see today and inspire new designs for underwater vehicles.

Are there any important historical papers from your field that have been published in JEB? If so, which paper, and how did it pave the way for later research?

Kelsey: Too many to name them all! I'm going to go with one that's had a huge impact on my thinking: Dubois and Ogilvy from 1978 (doi:10.1242/jeb.77.1.225). This is the third in a series of papers by Dubois and colleagues describing the surface pressures on a fish's body that are generated by its swimming movements. While all three are really critical for showing that our theoretical understanding of fish swimming based on the fluid mechanics of airfoils (streamlined shapes like airplane wings) holds up reasonably well when you look at real fishes, this one specifically looked at pressure on the tail and found that there are both pushing and pulling pressures acting on the tail. Folks (myself included!) often make the mistake of focusing on the pushing pressures and ignoring the pulling pressures, and much of my PhD research focused on what the implications are of making this mistake.

Are there any modern-day JEB papers that you think will be the classic papers of 2123?

We think Camp et al. (2018) (doi:10.1242/jeb.178160) and Li et al. (2022) (doi:10.1242/jeb.244294) will be classics because they show fish can generate maximal muscle power during suction feeding using their swimming muscles! This means that fish feeding and swimming are fundamentally linked together, which is different from animals with necks (like us) that help separate these functions. Understanding how these muscles are used to meet different, competing functions will be really important for understanding the evolution of both fish and vertebrate body plans.

What's next for you?

Yordano: I am starting my Comparative Biomechanics lab at Providence College this Fall! My research will explore unifying principles of muscle function across diverse animal groups. I am very excited to start a lab with undergraduate students. I am also going to be applying for grants to hire postdocs to do biomechanics and physiology research – so stay tuned!

Kelsey: I recently began my faculty position at the University of Calgary, and I'm still in the process of setting up my lab (thanks COVID!). My program seeks to extend our understanding of fish ecology by integrating swimming biomechanics with the context in which these biomechanics evolved. Right now, my students and I are thinking about inter- and intraspecific variation in swimming mechanics, behavior, and energetics, and how these interact with habitat characteristics like temperature and flow regime, leading to observed species distributions and abundances.

Yordano Jimenez's contact details: Department of Biology, Tufts University, Medford, MA 02155, USA.

Kelsey Lucas’s contact details: Biological Sciences, University of Calgary, Calgary, AB T2N 3T4, Canada.

E-mail: [email protected]; [email protected]

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Flexibility is a hidden axis of biomechanical diversity in fishes
J. Exp. Biol.