Dietary comparisons of six skate species (Rajidae) in south-eastern Australian waters

  • Michelle A. Treloar
  • Laurie J. B. Laurenson
  • John D. Stevens
Special Issue Skates


The diet of six skate species caught as bycatch in south-eastern Australian waters was examined over a 2-year period. The skates were segregated into two regions (continental shelf and continental slope) based on prey species and depth of capture. The shelf group consisted of four species, Dipturus sp. A, D. cerva, D. lemprieri and D. whitleyi, while the slope group comprised two species, Dipturus sp. B and D. gudgeri. The two groups varied in feeding strategies with the shelf species generally occupying a broader feeding niche and preying on a larger diversity of prey including a variety of crustaceans (brachyurans, anomurans, achelates, carideans and dendobranchiates), cephalopods, elasmobranchs and teleosts. Within the slope group, Dipturus sp. B and D. gudgeri were more specialised. Dipturus sp. B preyed primarily on anomurans (galatheids) and bachyurans (homolids), whereas D. gudgeri preyed primarily on teleosts. A size related change in diet was evident for all species with the exception of D. gudgeri in which all sizes preyed predominantly on teleosts. Smaller representatives of the four shelf species all preyed on numerous amounts of caridean shrimps, in particular Leptochela sydniensis. In contrast, the continental slope species, Dipturus sp. B consumed anomurans when small, shifting to brachyurans with increasing size. Of the six skate species examined in this study, three were secondary consumers (trophic level <3) and the remaining three tertiary consumers (trophic level >4). Although ANOSIM found significant differences in dietary composition between species within groups, there was some overlap in prey species amongst co-existing skates, which suggests that there is some degree of resource partitioning amongst them.


Trophic level Dipturus Prey Niche Partitioning 



The authors would like to express their gratitude to W. White and M. Bracccini for providing assistance with statistical analyses. Thanks also to J. Bizzarro and S. Irvine for their helpful comments on the manuscript. This research was supported by Deakin University (School of Life and Environmental Sciences), Victoria, Australia and CSIRO Marine and Atmospheric Research, Hobart, Australia. Finally we thank the American Elasmobranch Society (AES) for travel funds to attend and present this paper at the ‘Biology of Skates’ symposium held in conjunction with the annual AES meeting.


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Copyright information

© Springer Science+Business Media, Inc. 2007

Authors and Affiliations

  • Michelle A. Treloar
    • 1
    • 2
  • Laurie J. B. Laurenson
    • 1
  • John D. Stevens
    • 2
  1. 1.School of Life and Environmental SciencesDeakin UniversityWarrnamboolAustralia
  2. 2.CSIRO Marine and Atmospheric ResearchHobartAustralia

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