Ontogeny of head and caudal fin shape of an apex marine predator: The tiger shark (Galeocerdo cuvier)

Amy L. Fu, Neil Hammerschlag, George V. Lauder, Cheryl D. Wilga, Chi Yun Kuo, Duncan J. Irschick

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

How morphology changes with size can have profound effects on the life history and ecology of an animal. For apex predators that can impact higher level ecosystem processes, such changes may have consequences for other species. Tiger sharks (Galeocerdo cuvier) are an apex predator in tropical seas, and, as adults, are highly migratory. However, little is known about ontogenetic changes in their body form, especially in relation to two aspects of shape that influence locomotion (caudal fin) and feeding (head shape). We captured digital images of the heads and caudal fins of live tiger sharks from Southern Florida and the Bahamas ranging in body size (hence age), and quantified shape of each using elliptical Fourier analysis. This revealed changes in the shape of the head and caudal fin of tiger sharks across ontogeny. Smaller juvenile tiger sharks show an asymmetrical tail with the dorsal (upper) lobe being substantially larger than the ventral (lower) lobe, and transition to more symmetrical tail in larger adults, although the upper lobe remains relatively larger in adults. The heads of juvenile tiger sharks are more conical, which transition to relatively broader heads over ontogeny. We interpret these changes as a result of two ecological transitions. First, adult tiger sharks can undertake extensive migrations and a more symmetrical tail could be more efficient for swimming longer distances, although we did not test this possibility. Second, adult tiger sharks expand their diet to consume larger and more diverse prey with age (turtles, mammals, and elasmobranchs), which requires substantially greater bite area and force to process. In contrast, juvenile tiger sharks consume smaller prey, such as fishes, crustaceans, and invertebrates. Our data reveal significant morphological shifts in an apex predator, which could have effects for other species that tiger sharks consume and interact with.

Original languageEnglish (US)
JournalJournal of Morphology
DOIs
StateAccepted/In press - 2016

Fingerprint

Galeocerdo cuvier
Tigers
Sharks
fins
ontogeny
Head
predators
Tail
tail
Bahamas
Elasmobranchii
Bite Force
Turtles
animal ecology
Body Size
Fourier Analysis
Invertebrates
Locomotion
Ecology
digital images

Keywords

  • Ecology
  • Form
  • Morphology
  • Ontogeny
  • Sharks

ASJC Scopus subject areas

  • Animal Science and Zoology
  • Developmental Biology

Cite this

Ontogeny of head and caudal fin shape of an apex marine predator : The tiger shark (Galeocerdo cuvier). / Fu, Amy L.; Hammerschlag, Neil; Lauder, George V.; Wilga, Cheryl D.; Kuo, Chi Yun; Irschick, Duncan J.

In: Journal of Morphology, 2016.

Research output: Contribution to journalArticle

Fu, Amy L. ; Hammerschlag, Neil ; Lauder, George V. ; Wilga, Cheryl D. ; Kuo, Chi Yun ; Irschick, Duncan J. / Ontogeny of head and caudal fin shape of an apex marine predator : The tiger shark (Galeocerdo cuvier). In: Journal of Morphology. 2016.
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