Dissertation/Thesis Abstract

Turtle Tracking Trouble: The Influence of Carapace Morphology and Composition on Transmitter Adhesion to Loggerhead (Caretta caretta) Sea Turtle Keratin
by Hoffman, Katherine M., M.S., College of Charleston, 2020, 101; 27997663
Abstract (Summary)

Satellite telemetry provides spatial distribution data across populations and species. Multiple sea turtle studies indicate variability in track durations both within and between species. Intraspecies track duration disparities suggest possible effects of transmitter adhesion; thus, potential interactions between carapace morphology and composition on transmitter adhesion to loggerhead sea turtles scutes were evaluated. Epoxy adhesion strength across 143 scute subsamples ranged from 9 to 48 N, but was highly variable (CV = 0.4) and unrelated to scute attributes (Objective 1). Fatty acid profiles (FAP) from 64 scute subsamples across five individuals were generated using gas chromatography with flame ionization detection (Obj. 2). Scute total fat content was low (mean = 0.16%, maximum = 0.42%), and did not correlate with mean epoxy adhesion to corresponding scute subsamples (r = −0.4). Principal component analysis revealed long chain fatty acids drove separation in FAPs between individuals. Following identification of tile as a suitable substitute keratin substrate (Obj. 3), a laboratory study (Obj. 4) tested epoxy adhesion with respect to 0º vs. 30º shear angles (simulating carapace slope) and small vs. large epoxy footprints (simulating transmitter sizes). No detachments occurred for small (n = 10) or large (n = 10) transmitters at 0º at a maximum sustained force of 979 N for 20 minutes. Lastly, a field study evaluated the effects of biofouling and seawater submergence on surrogate transmitter retention (Obj. 5) for epoxy footprints and simulated carapace angles. Six of 20 small and two of 19 large transmitters detached from tile after 67 days, but results were not significantly different (P = 0.24) and no detachments occurred for angled samples (n = 40). Variability observed in epoxy adhesion to loggerhead keratin and early detachment of surrogate transmitters in situ suggest that transmitter detachment may be implicated in shorter track durations.

Indexing (document details)
Advisor: Arendt, Michael
Commitee: Bowden, John, Williams, Gabriel, Zardus, John
School: College of Charleston
Department: Marine Biology
School Location: United States -- South Carolina
Source: MAI 82/1(E), Masters Abstracts International
Subjects: Biology, Zoology
Keywords: Adhesion, Epoxy, Fatty acids, Keratin, Satellite telemetry, Sea turtle
Publication Number: 27997663
ISBN: 9798662407435
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