Predator–prey relationships and foraging ecology of a marine apex predator with a wide temperate distribution

Barnett, Adam, Abrantes, Kátya, Stevens, John D., Yick, Jonah L., Frusher, Stewart D., and Semmens, Jayson M. (2010) Predator–prey relationships and foraging ecology of a marine apex predator with a wide temperate distribution. Marine Ecology Progress Series, 416. pp. 189-200.

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Abstract

The diet of the broadnose sevengill shark Notorynchus cepedianus was investigated over 3 years from 2 coastal locations in south-east Tasmania: the Derwent Estuary and Norfolk Bay. In general, individuals from both locations consumed the same broad dietary categories (sharks, batoids, teleosts and mammals). However, within these categories, species composition differed. Variations in chondrichthyan prey consumed matched estimations of prey abundance: Mustelus antarcticus was the primary prey in Norfolk Bay, where it was also the most abundant prey species; similarly, Squalus acanthias was an important prey and the most abundant in the Derwent Estuary. A decline in the catch rates of N. cepedianus and elasmobranch prey, in particular M. antarcticus over 3 years coincided with declines in dietary occurrence of M. antarcticus. Also, N. cepedianus and M. antarcticus abundances were both higher in Norfolk Bay than the Derwent Estuary. The correlation with diet and estimations of predator and prey relative abundance suggests N. cepedianus may move into coastal areas to exploit regular seasonal abundant resources, but they can also be versatile opportunistic predators that exploit a temporarily abundant resource.

Item ID: 16991
Item Type: Article (Research - C1)
ISSN: 1616-1599
Keywords: shark; Notorynchus cepedianus; diet; spatial scale; Mustelus antarcticus
Date Deposited: 15 May 2011 09:59
FoR Codes: 06 BIOLOGICAL SCIENCES > 0602 Ecology > 060201 Behavioural Ecology @ 100%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970106 Expanding Knowledge in the Biological Sciences @ 100%
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