E-Thesis 52 views 22 downloads
Judicious Power Use in Whale Sharks (Rhincodon typus); Under What Conditions Do They Employ Power Above Minimum? / AMY FISHER
Swansea University Author: AMY FISHER
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PDF | E-Thesis – open access
Copyright: The Author, Amy Fisher, 2024 Distributed under the terms of a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0).
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Abstract
There is a strong selection pressure for animals to move in a way that maximises efficiency, often incurring minimal costs. By using the Vector of Dynamic Body Acceleration (VeDBA),as a measure of power in relation to vertical velocity, the “Minimum Power” (Pmin) can be calculated by a functional re...
| Published: |
Swansea, University, Wales, UK
2025
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| Institution: | Swansea University |
| Degree level: | Master of Research |
| Degree name: | MRes |
| Supervisor: | Wilson, R. P., and Shepard, E. L. C. |
| URI: | https://cronfa.swan.ac.uk/Record/cronfa69639 |
| Abstract: |
There is a strong selection pressure for animals to move in a way that maximises efficiency, often incurring minimal costs. By using the Vector of Dynamic Body Acceleration (VeDBA),as a measure of power in relation to vertical velocity, the “Minimum Power” (Pmin) can be calculated by a functional relationship for any speed of an animal in a fluid medium.“Putative Power above Minimum” (PPAmin), is a metric which quantifies how much the power to move exceeds Pmin, indicated by subtracting Pmin from VeDBA. The dynamics of energy expenditure and efficiency of swimming animals are critically dependent on the drag and velocity as major modulators of PPAmin. For 15 whale sharks (Rhincodon typus) tagged with acceleration/depth tags, periods when substantial PPAmin occurred were identified in relation to periods of dive descent, ascent and level swimming, examined with the corresponding body geometry, depth, time of day and swim track tortuosity (a proxy for feeding). Within the whale shark data, incidences of PPAmin during ascents (mean = 0.0161 g ±0.0094 SD) and predominantly when swimming horizontal (0.016 g ±0.021 SD) are suggested to be due to an increase in the drag coefficient by the animal opening its mouth to feed. This effect is magnified by increased surface drag (within 2 m of the water surface). As power usage increases with the cube of swim speed, other high PPAmin values likely correspond to speed increases, principally observed during rapid descents (0.012 g ±0.011 SD). Crucially, PPAmin is suggested to be a due to human interactions. Instances of PPAmin may negatively impact the energy budget of the endangered whale sharks, which is of particular concern for this species working on an energetic “knife-edge”. |
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| Item Description: |
A selection of content is redacted or is partially redacted from this thesis to protect sensitive and personal information. |
| Keywords: |
Energetics, Behaviour, Whale Shark, Power use, Biologging, Depth, Feeding. |
| College: |
Faculty of Science and Engineering |
| Funders: |
Swansea Lab for Animal Movement (SLAM) |