Dennison-Gibby Sophie

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Dennison-Gibby
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Sophie
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  • Article
    Hyperbaric tracheobronchial compression in cetaceans and pinnipeds
    (Company of Biologists, 2020-02-10) Denk, Michael ; Fahlman, Andreas ; Dennison-Gibby, Sophie ; Song, Zhongchang ; Moore, Michael J.
    Assessment of the compressibility of marine mammal airways at depth is crucial to understanding vital physiological processes such as gas exchange during diving. Very few studies have directly assessed changes in cetacean and pinniped tracheobronchial shape, and none have quantified changes in volume with increasing pressure. A harbor seal, gray seal, harp seal, harbor porpoise and common dolphin were imaged promptly post mortem via computed tomography in a radiolucent hyperbaric chamber. Volume reconstructions were performed of segments of the trachea and bronchi of the pinnipeds and bronchi of the cetaceans for each pressure treatment. All specimens examined demonstrated significant decreases in airway volume with increasing pressure, with those of the harbor seal and common dolphin nearing complete collapse at the highest pressures. The common dolphin bronchi demonstrated distinctly different compression dynamics between 50% and 100% lung inflation treatments, indicating the importance of air in maintaining patent airways, and collapse occurred caudally to cranially in the 50% treatment. Dynamics of the harbor seal and gray seal airways indicated that the trachea was less compliant than the bronchi. These findings indicate potential species-specific variability in airway compliance, and cessation of gas exchange may occur at greater depths than those predicted in models assuming rigid airways. This may potentially increase the likelihood of decompression sickness in these animals during diving.
  • Article
    Stranded beluga (Delphinapterus leucas) calf response and care: reports of two cases with different outcomes
    (Norwegian Polar Institute, 2021-11-26) Goertz, Caroline ; Woodie, Kathy ; Long, Brett ; Hartman, Lisa ; Gaglione, Eric ; Christen, Dennis ; Clauss, Tonya ; Flower, Jennifer ; Tuttle, Allison ; Richard, Carey ; Romano, Tracy ; Schmitt, Todd ; Otjen, Eric ; Osborn, Steve ; Aibel, Steve ; Binder, Tim ; Van Bonn, William ; Castellote, Manuel ; Mooney, T. Aran ; Dennison-Gibby, Sophie ; Burek-Huntington, Kathy ; Rowles, Teresa K.
    Given the remote, rugged areas belugas typically inhabit and the low rehabilitation success rate with any cetacean, it is rare to have the opportunity to rescue a live-stranded beluga. The Alaska SeaLife Center cared for two stranded beluga calves with two different outcomes. In 2012, a neonatal male beluga calf (DL1202) stranded following intense storms in Bristol Bay. In 2017, a helicopter pilot discovered a stranded male beluga calf (DL1705) during a flight over Cook Inlet. The Alaska SeaLife Center transported both calves for rehabilitation and utilized supportive care plans based on those for other species of stranded cetaceans and care of neonatal belugas at zoological facilities. Diagnostics included complete blood counts, serum chemistries, microbial cultures, hearing tests, imaging and morphometric measurements to monitor systemic health. Treatments included in-pool flotation support; antimicrobials; gastrointestinal support; and close monitoring of respirations, urination, defecation and behaviour. After three weeks of supportive care, the Bristol Bay calf (DL1202) succumbed to sepsis secondary to a possible prematurity-related lack of passive transfer of antibodies. After seven weeks, the Cook Inlet calf (DL1705) recovered and all medications were discontinued. Unable to survive on his own, he was declared non-releasable and placed in long-term care at a zoological facility, to live with other belugas. Aspects and details from successful cases of cetacean critical care become important references especially vital for the survival of essential animals in small, endangered populations.