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Marine Ecology Progress Series

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MEPS 425:247-260 (2011)  -  DOI:

Dietary niche overlap in a nearshore elasmobranch mesopredator community

Jeremy J. Vaudo*, Michael R. Heithaus

Marine Science Program, Department of Biological Sciences, Florida International University, 3000 NE 151 Street, North Miami, Florida 33181, USA

ABSTRACT: Understanding mesopredator trophic interactions is crucial to understanding the dynamics of food webs because mesopredators provide the link between apex predators and lower trophic levels. Using stable isotopic analysis and stomach content analysis, we examined dietary niche overlap within a diverse elasmobranch mesopredator community in Shark Bay, Western Australia. Isotopic values (δ13C and δ15N) were consistent with most species being highly dependent on a seagrass-based food web. Differences were observed between the mean isotopic values of species, but there was a great deal of overlap in the isotopic niche space used by the community when examined at the level of individuals. Stomach contents also suggest dietary overlap among the diets of Himantura spp. and Glaucostegus typus, which contained many of the same prey species, primarily crustaceans typically associated with seagrass habitats, although in different proportions. Diet data also suggest that, despite having isotopic values similar to other species, Pastinachus atrus appears to feed on sandflat-associated species. In this community, variation within the groups examined, possibly due to individual specialization, appears to result in high resource overlap and may be a key component allowing for high diversity in this system and is perhaps crucial to understanding the role of mesopredators in community trophic dynamics.

KEY WORDS: Stable isotope · Resource partitioning · Individual specialization · Stingray · Batoid · Elasmobranch · Shark

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Cite this article as: Vaudo JJ, Heithaus MR (2011) Dietary niche overlap in a nearshore elasmobranch mesopredator community. Mar Ecol Prog Ser 425:247-260.

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