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 but also the huge variety of animals and physiological systems that are essential for the ‘comparative’ approach. Matthew Gilbert is an author on ‘ Measuring maximum heart rate to study cardiac thermal performance and heat tolerance in fishes’, published in JEB. Matthew is an Assistant Professor of Animal Physiology at the Institute of Arctic Biology, University of Alaska Fairbanks, USA, investigating environmental drivers of cardiorespiratory and energetic plasticity, thermal physiology and exercise physiology.

Matthew Gilbert

How did you become interested in biology?

I grew up participating in various sports, and ice hockey in particular. As I started to take my athletic performance more seriously, I developed a passion for physical training, which grew into an interest in exercise physiology. I no longer play hockey but continue to enjoy pursuing new athletic challenges, which has further stoked my interest in physiology. A second important factor that fostered my interest in biology was that I grew up in a small remote community in northern Canada that placed a high value on the outdoors. As such, I had a lot of freedom to spend time in nature as a kid, and to experience Canada's vast northern wilderness as I grew up.

Describe your scientific journey and your current research focus

While I had an appreciation for nature and exercise performance when I started university, I had little exposure to scientific research or to career paths in science. As I progressed through my undergraduate program in physiology at the University of Alberta with the aim of attending medical school, I gained research exposure from professors who would integrate their own research into our courses. In my third year, Dr Keith Tierney gave a guest lecture discussing his research on exercise physiology in salmon, which perfectly aligned with my interests. I approached Keith following this lecture and went on to complete my MSc research with him. This research focused on understanding physiological limitations to migration in Arctic char, a key subsistence fish for Inuit in the Canadian Arctic.

I then moved to the University of British Columbia for my PhD with Dr Tony Farrell, given his renowned expertise in cardiorespiratory and thermal physiology. My PhD research more broadly examined the thermal physiology of Arctic char in the context of rapid northern climate change. During this research, I became fascinated with the physiological flexibility that allows Arctic fishes to thrive despite harsh winters and extreme seasonality. For instance, one remarkable aspect of the biology of migratory Arctic char is that they commonly only eat for 4–8 weeks over the summer and won't eat for the rest of the year! I received Weston Family and NSERC postdoctoral fellowships to explore mechanisms that allow Arctic char to maintain a positive energy budget in the face of such feast and famine. For this work, I moved to the University of New Brunswick to work with Dr Ben Speers-Roesch, whose research program examines complementary questions regarding physiological overwintering strategies.

Given my northern upbringing and research, it was always my goal to more permanently return to the North. I have recently started as an Assistant Professor of Animal Physiology at the University of Alaska Fairbanks. My research focuses on environmental drivers of cardiorespiratory and energetic plasticity, thermal physiology and exercise physiology, with a strong focus on questions that are best addressed in Arctic and northern fishes.

Researchers fishing for sculpin and cod through cracks in the Arctic sea ice to study cardiorespiratory seasonal plasticity in Kitikmeot Region, Nunavut, Canada.

Researchers fishing for sculpin and cod through cracks in the Arctic sea ice to study cardiorespiratory seasonal plasticity in Kitikmeot Region, Nunavut, Canada.

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

For well over 100 years, experimental biologists have been intrigued with the strong controlling influence of temperature on heart rate. From fish to mammals, as body temperature increases, so does heart rate. However, at high temperatures heart function deteriorates. This relationship can be particularly important for fish, because their body temperature matches that of their environment. In our paper, we review a method in which maximum heart rate is assessed in anaesthetized fish while they are rapidly warmed up to characterize how temperature influences limits to heart rate and to identify upper temperature limits for heart function. The method has proven particularly useful to study the ability of species to adjust their heart function with prolonged exposure to different temperatures. It has also been used explore the interactive effects of temperature and multiple other factors such as diet, oxygen levels and contaminants. While the method does have limits regarding what it can reveal about heart function, it is quite simple and quick to perform on large numbers of fish, so it can enable larger or more complex study designs. These strengths also mean that the method is well suited for field studies in more remote locations where alternatives are impractical. The method can be used to both improve our basic understanding of the effects of temperature on fish, and to explore how they may be impacted by changes in their environment. Such advancements are valuable given that climate change is progressing rapidly and considering that with approximately 35,000 fish species, we have just scratched the surface on understanding the diversity of physiological responses to temperature among fishes.

What do you enjoy most about research, and why?

Our lab’s program integrates laboratory and Arctic field-based physiological research. For instance, a single study often involves laboratory experiments where fish are raised under specific environmental conditions, and an Arctic field component where we seek out similar conditions to determine how our laboratory findings manifest in more complex natural settings. The initial integration of knowledge and new ideas into the development of research questions, hypotheses and experimental design, with subsequent data analysis and interpretation, is intellectually rewarding. The application of physiological methods across levels of organization from biochemical to whole-animal levels is technically challenging. Field research in a remote setting involving travelling by boat, ATV and snow-machine, camping, capturing fish, adapting physiological methods for a field setting, and lots of problem solving on the fly under challenging Arctic field conditions is also psychologically and physically demanding. The remarkable breadth of challenges and opportunities presented by this work keeps me highly engaged and is certainly my favorite thing about it.

What's next for you?

As a new professor I am currently growing my research program in Alaska, recruiting students, and developing new collaborations!

Matthew Gilbert’s contact details: Institute of Arctic Biology, University of Alaska Fairbanks, 2140 N Koyukuk Dr, Fairbanks, AK 99775, USA.

E-mail: [email protected]

Gilbert
,
M. J. H.
,
Hardison
,
E. A.
,
Farrell
,
A. P.
,
Eliason
,
E. J.
and
Anttila
,
K.
(
2024
).
Measuring maximum heart rate to study cardiac thermal performance and heat tolerance in fishes
.
J Exp. Biol.
227
,
jeb247928
.