Whale sharks increase swimming effort while filter feeding, but appear to maintain high foraging efficiencies
Autor: | David E. Cade, Rafael Parra, Robert Cooper, D. Harry Webb, Alistair D. M. Dove, J. Jacob Levenson |
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Rok vydání: | 2020 |
Předmět: |
0106 biological sciences
Male Physiology Foraging Endangered species Aquatic Science Whale shark 010603 evolutionary biology 01 natural sciences Zooplankton Latitude biology.animal Animals Molecular Biology Planktivore Mexico Ecology Evolution Behavior and Systematics Swimming biology Whale 010604 marine biology & hydrobiology Wildlife tourism Endangered Species biology.organism_classification Fishery Insect Science Sharks Animal Science and Zoology |
Zdroj: | The Journal of experimental biology. 223(Pt 11) |
ISSN: | 1477-9145 |
Popis: | Whale sharks (Rhincodon typus Smith 1828) – the largest extant fish species – reside in tropical environments, making them an exception to the general rule that animal size increases with latitude. How this largest fish thrives in tropical environments that promote high metabolism but support less robust zooplankton communities has not been sufficiently explained. We used open-source inertial measurement units (IMU) to log 397 hours of whale shark behavior in Yucatan, Mexico, at a site of both active feeding and intense wildlife tourism. Here we show that the strategies employed by whale sharks to compensate for the increased drag of an open mouth are similar to ram-feeders five orders of magnitude smaller and one order of magnitude larger. Presumed feeding constituted 20% of the total time budget of four sharks, with individual feeding bouts lasting up to 11 consecutive hrs. Compared to normal, sub-surface swimming, three sharks increased their stroke rate and amplitude while surface feeding, while one shark that fed at depth did not demonstrate a greatly increased energetic cost. Additionally, based on time-depth budgets, we estimate that aerial surveys of shark populations should consider including a correction factor of 3 to account for the proportion of daylight hours that sharks are not visible at the surface. With foraging bouts generally lasting several hours, interruptions to foraging during critical feeding periods may represent substantial energetic costs to these endangered species, and this study presents baseline data from which management decisions affecting tourist interactions with whale sharks may be made. |
Databáze: | OpenAIRE |
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