The diet of wobbegongs in NSW: preliminary results

Publication Type:Book
Year of Publication:2008
Authors:C. Huveneers, Harcourt, R. G., Univ, V. Fisheries
Series Editor:R. E. Forrest, Scandol, J. P., Pitcher, T. J.
Series Title:Experts and Data Workshop, Cronulla (Australia), 8-10 Dec 2003
Volume:14
Series Volume:Book, Whole
Number of Pages:111-118
Publisher:Vancouver
City:BC (Canada)
ISBN Number:1198-6727
Keywords:Article Geographic Terms: PSE, Australia, New South Wales, Article Subject Terms: Cannibalism, Article Taxonomic Terms: Orectolobus maculatus, diets, Feeding behaviour, Food organisms, marine, Orectolobus ornatus, predation, Predators, Spotted wobbegong, stomach content, Trophic levels
Abstract:

Wobbegongs are top predators which have potentially strong impacts on lower trophic organisms. A diet study was undertaken on the three species of wobbegongs found in NSW using commercially hooked sharks. 403 sharks were dissected but only 115 stomachs had any prey item other than bait (28.5%). Teleosts were the major group found in wobbegong stomachs with unidentified fish the most prominent prey item. Other important teleosts found in wobbegong diet include Carangidae, Scrombidae and Labridae. Cephalopods (mainly octopus) were the second most common prey items and elasmobranchs including Orectolobidae, Rajiformes and Triakidae were also found in O. ornatus stomachs. The results obtained here accord with other accounts of wobbegong diet based on significantly smaller samples, although no crustaceans were found in this study. Most sharks were hooked in their gut or oesophagus (90.4%) and had a single prey item only in the gut (46%). Wobbegongs were calculated to be tertiary consumers with a trophic level of 4.23. Most prey items were demersal animals and reef-associated, consistent with the benthic environment preferred by wobbegongs.

Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith