Welcome to the Thometz Lab
How do physiological traits influence the behavior, ecology, and survival of marine mammals? This question is central to understanding how different species are able to respond to both anthropogenic disturbance and environmental change. Currently, marine mammals face a variety of challenges including: fisheries interactions, resource limitation, habitat degradation, noise pollution, and climate change. These issues and many more are concerning to biologists, resource managers, and conservationists. We study physiological and behavioral traits at the individual level and use these data to consider population level implications. Further, we utilize a variety of laboratory and field-based techniques to gain a comprehensive understanding of the physiological capacities and limitations of various marine mammal species. As understanding the underlying physiology of a given species and its ability to adapt or respond to changing conditions can provide critical information to aid in management and conservation efforts.
Lab News!
August 2024
New Publication in Endangered Species Research
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Thometz Lab Alumna, Sophia Lyon (pictured), is first author on a paper published in the journal Endangered Species Research, titled: "Foraging ecology of southern sea otters at the northern range extent informs regional population dynamics". This paper was a collaborative effort between the Thometz Lab at USF, the United States Geological Survey, and the Monterey Bay Aquarium. Sophia's work is the first to document key foraging metrics (e.g. diet composition, diet diversity, energy intake rates) for sea otters at the northern range boundary; a section of the current southern sea otter range that is critical for range expansion and species recovery. Overall her work highlights possible effects of occupation time and range stagnation, identifies unique aspects of the prey resource base, and provides insight into the stall in northward range expansion.
May 2024
New Publication in Aquatic Mammals Journal
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Thometz Lab Alumna, Mariah Tengler (pictured), is first author on a paper published in the journal Aquatic Mammals, titled: "Comparative muscle physiology of ringed (Pusa hispida), bearded (Erignathus barbatus), and spotted (Phoca largha) seals from the Bering and Chukchi Seas". This paper was a collaborative effort between the Thometz Lab at USF, the Reichmuth Lab at UC Santa Cruz, the Alaska Department of Fish and Game, and the Dearolf Lab at Hendrix College. We report muscle myoglobin levels, buffering capacity, and fiber type profiles for three species of Arctic seals across a range of age classes. Our data suggest a strong link between muscle physiology, diving behavior, and life history strategies, and provide insight into the physiological capacities of these vulnerable species.
January 2023
New Publication in Journal of Experimental Biology
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Dr. Thometz and colleagues published a paper in the Journal of Experimental Biology, titled: "Maintaining control: metabolism of molting Arctic seals in water and when hauled out". The results of this research provide insight into how submergence in water affects the metabolic demands of these species, particularly during the annual molt when they shed and regrow their fur and several layers of skin.
May 2021
Sophia Lyon Defends Her Masters Thesis Research
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Graduate student Sophia Lyon defended her masters thesis work, titled: "Investigations of southern sea otter foraging ecology at the northern range extent". Sophia's research has filled important gaps in our understanding of sea otter foraging ecology in California. And her work provides insight into the historic lack of northward range expansion for this threatened keystone species. What an accomplishment!! Bravo!!
January 2021
New Publication in Conservation Physiology
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Dr. Thometz and colleagues published a paper in the journal Conservation Physiology, titled: "Molting strategies of Arctic seals drive annual patterns in metabolism". The results of this research improve our understanding of the energy requirements and molting phenology of three Arctic seal species: spotted, ringed, and bearded seals. This work also highlights the unique benefits of working with trained seals in human care, as these types of metabolic data cannot currently be collected with free-ranging seals. Thank you to the amazing team of researchers, trainers, and ice seals that made this work possible.
January 2021
The Society for Integrative and Comparative Biology (SICB) & the Alaska Marine Science Symposium (AMSS) Annual Meetings
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The Thometz Lab had great showings at this year's virtual SICB and AMSS meetings. For SICB, Michelle Hartwick presented an oral presentation of her thesis research titled: "Using physiological measures of captive seals to inform best practices of rapid body condition assessments of wild Artic seals". At AMSS, the Thometz lab contributed to three different poster presentations: (1) “The effect of molting status on resting metabolism of Alaskan seals in water and during haul out”, led by Holly Hermann-Sorensen, (2) “Cardiorespiratory patterns in resting Alaskan seals”, led by Ryan Jones, and (3) “Improving best practices for field body condition assessments of wild Arctic seals”, led by Michelle Hartwick.
August 2020
Michelle Hartwick Defends Her Masters Thesis Research
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Graduate student Michelle Hartwick defended her masters thesis work, titled: "Assessing seasonal changes in body condition for spotted (Phoca largha), ringed (Pusa hispida), and bearded (Erignathus barbatus) seals". Her comprehensive thesis has provided a wealth of data pertaining to typical body condition profiles in these cryptic species. Further, her work can be used to establish best practices for species-specific body condition assessments of wild seals. Congratulations on a fantastic thesis!!
May 2020
USF Creative Activities & Research Day (CARD)
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Two Thometz Lab graduate students received awards for their presentations at CARD this year!! Michelle Hartwick (left) received the award for Best Oral Presentation by a graduate student in the sciences for her presentation: "Evaluating Body Condition in Bearded, Ringed, and Spotted Seals". Sophia Lyon (right) received the award for Best Poster Presentation by a graduate student for her poster: "Investigations of southern sea otter foraging ecology at the northern range extent". Way to go you two!! SCIENCE!!
January 2020
Sophia Lyon Awarded Grant from Sea Otter Foundation & Trust
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Graduate student Sophia Lyon received an important grant from the Sea Otter Foundation and Trust (SOFT) to fund part of her graduate research studying the foraging ecology of southern sea otters at their northern range extent. We are excited to see what Sophia learns about this segment of the population... stay tuned!
December 2019
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World Marine Mammal Conference. Barcelona, Spain
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The Thometz Lab and colleagues traveled to Barcelona to present their research on Arctic seal physiology. Dr. Thometz gave a presentation on the energetics of molt in ringed, bearded, and spotted seals; Mariah Tengler presented a poster about ice seal muscle physiology; Michelle Hartwick presented a poster concerning ice seal body condition. In addition, our colleagues at UCSC (pictured: Dr. Colleen Reichmuth), UBC and other institutions presented exciting research regarding ice seals and a number of other marine mammal species.
November 2019
Mariah Tengler Defends Her Masters Thesis Research
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After two years in the Thometz Lab, Mariah Tengler defended her masters thesis work, titled: "Physiological development of locomotor muscle in ringed, bearded, and spotted seals". Her work contributes to our understanding of diving physiology in these species and provides insight into their behavioral flexibility in light of sea ice loss and environmental change. Mariah has already accepted a position with The Marine Mammal Center and we cannot wait to see what the next steps in her career hold!! Cheers!!
January 2019
Society for Integrative and Comparative Biology (SICB) Annual Meeting. Tampa, FL.
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The Thometz Lab traveled to Tampa, FL to present a poster and two oral presentations at the annaul SICB meeting. Mariah Tengler gave an oral presentation on the physiological properties of bearded seal locomotor muscle, Michelle Hartwick presented a poster of her research concerning seasonal changes in Arctic seal body condition, and Dr. Thometz gave an oral presentation focused on the metabolic consequences of molt in spotted, ringed, and bearded seals.
May 2018
Research Trip to the Alaska SeaLife Center (Seward, AK)
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Dr. Thometz traveled to Seward, Alaska to work with our research partners at the Alaska SeaLife Center. In the photo to the left, Dr. Thometz is working cooperatively with a young male ringed seal named Pimniq, to take detailed photos of his coat during his annual molt. During their annual molt, Arctic seals shed all of their fur and several layers of their epidermis. We are conducting research to better understand the physiological and energetic consequences of molt in ringed, bearded, and spotted seals.
April 2018
USF Creative Activities & Research Day (CARD)
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USF Junior Esther Grady (pictured) and graduate student Mariah Tengler presented posters at USF's annual Creative Activities and Research Day. Esther presented her research: "Using Photogrammetry to Examine Ontogenetic and Longitudinal Patterns of Growth and Body Condition in Artic Seals". Mariah presented her research: "Aerobic and Anaerobic Properties of Bearded Seal Locomotor Muscle".
January 2018
Society for Integrative and Comparative Biology (SICB) Annual Meeting. San Francisco, CA.
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The Thometz Lab presented poster and oral presentations of our collaborative research project, examining the unique physiology of bearded seals (Erignathus barbatus).