Ontogenetic diet shifts and prey selection in nursery bound lemon sharks, Negaprion brevirostris, indicate a flexible foraging tactic

Steven P. Newman, Richard D. Handy, Samuel H. Gruber

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Ontogenetic variations in shark diet are often qualitatively inferred from dietary analysis and hindered by high levels of unidentified prey or small sample sizes. This study focused on nursery bound lemon sharks (Negaprion brevirostris, n = 396), enabling some control over the confounding variables of prey choice associated with ontogeny. Nursery bound lemon sharks exhibited weak ontogenetic variation in dietary composition with high levels of dietary overlap. Variation in prey preference of lemon sharks with ontogeny was complex, but revealed a continuous shift from predominantly opportunistic benthic foraging as neonates to more selective piscivory with increasing shark size while in the nursery. Lemon sharks demonstrated a discrete ontogenetic shift in the number of prey consumed and stomach content weight (Kruskal-Wallis tests p < 0.01), as well as prey size (ANOVA, p < 0. 001). All sizes of sharks exhibited positive size selection of prey (Mann-Whitney U tests, p < 0. 01). However, the lack of size preference by all but the largest lemon sharks for their major prey (yellowfin mojarra, Gerres cinereus), suggests neonate sharks, while capable of occasionally foraging on large prey, are relatively inept opportunistic foragers. This was evident in high diet breadth, low diversity of consumed prey and lower trophic level than larger sharks. This study represents the first quantitative analysis of ontogenetic variation in prey preference and size selection in sharks, indicating a flexible foraging tactic in lemon sharks and the importance of hunting ability and predator size in prey choice.

Original languageEnglish
Pages (from-to)115-126
Number of pages12
JournalEnvironmental Biology of Fishes
Volume95
Issue number1
DOIs
StatePublished - Sep 1 2012

Fingerprint

Negaprion brevirostris
prey selection
shark
sharks
foraging
diet
ontogeny
neonates
prey preference
size selection
prey size
neonate
quantitative analysis
piscivory
stomach
dietary overlap
analysis of variance
testing
predators
stomach content

Keywords

  • Carcharhinidae
  • Elasmobranch
  • Learning
  • Preference
  • Size selection

ASJC Scopus subject areas

  • Aquatic Science
  • Ecology, Evolution, Behavior and Systematics

Cite this

Ontogenetic diet shifts and prey selection in nursery bound lemon sharks, Negaprion brevirostris, indicate a flexible foraging tactic. / Newman, Steven P.; Handy, Richard D.; Gruber, Samuel H.

In: Environmental Biology of Fishes, Vol. 95, No. 1, 01.09.2012, p. 115-126.

Research output: Contribution to journalArticle

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