[All-postdocs] Bioseminar - Caroline Rzucidlo

[Ana Velez]

Woods Hole Oceanographic Institution
Biology Department Seminar

Thursday, December 12, 2024 - 12:00 Noon

Caroline Rzucidlo
WHOI-MIT Joint Program Student

Physiological Correlates of Reproductive Success: How Weddell Seals Strike a Balance Between Current and Future Reproduction
Long-term energy management impacts survival and reproductive success across marine mammals. A >60-year Weddell seal (Leptonychotes weddellii) demographic study in Erebus Bay, Antarctica offers an opportunity to investigate how an individual's physiological attributes relate to lifetime reproductive output. For example, female Weddell seals with higher reproductive outputs (HRO, produced more pups for their age), have higher 'stress hormone' cortisol levels during lactation when compared to females with lower reproductive outputs. Higher cortisol may allow HRO females to better prioritize mobilization of lipid stores while defending their muscle mass. HRO females also manage their energy stores more effectively when they take a year of 'reproductive rest'. In addition to provisioning pups with energy across lactation, females transfer iron, a critical component of hemoproteins that allow for large oxygen storage capacity in diving mammals. Using natural iron isotope fractionation, we 'tracked' iron movement, determining that adult females deplete their endogenous stores and transfer to pups for aerobic dive development. Physiological measurements are critically important to understanding energy balance in free-living animals, however they are logistically difficult and costly. Thus, we validated non-invasive workflows using infrared imaging coupled with Eulerian video magnification to obtain accurate heart and respiration rates- proxies for metabolic rate- across species in a controlled zoological setting, then in pinnipeds in the field. Throughout, resource allocation decisions appeared to shape reproductive phenology (ovulation timing, pregnancy) for the following year. Together, carry-over effects and toolset development for energetic indices are critical to understanding lifetime reproductive potential in marine mammals.

HYBRID! In Person: Redfield Auditorium Zoom: https://whoi-edu.zoom.us/j/97000865816 Meeting ID: 970 0086 5816 By phone: Find your local number: https://whoi-edu.zoom.us/u/adIvMow3LQ

For questions, contact

Ana María Vélez
Administrative Associate
Ph: (+1)(508)289-2334
[signature_1005462319]

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