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RESEARCH ARTICLE
Contents Vol 61(1)

The influence of sex and maturity on the diet, mouth morphology and dentition of the Port Jackson shark, Heterodontus portusjacksoni

David Mark Powter A B , William Gladstone A and Margaret Platell A
+ Author Affiliations
- Author Affiliations

A School of Environmental and Life Sciences, Ourimbah Campus, University of Newcastle, PO Box 127, Ourimbah, NSW 2258, Australia.

B Corresponding author. Email: david.powter@newcastle.edu.au

Marine and Freshwater Research 61(1) 74-85 https://doi.org/10.1071/MF09021
Submitted: 3 February 2009  Accepted: 9 June 2009   Published: 29 January 2010

Abstract

Dietary studies are essential for an understanding of elasmobranch ecology and their role in marine ecosystems. The diet, head morphology and dentition of Heterodontus portusjacksoni, an abundant, epibenthic shark in the coastal waters of temperate eastern Australia, were examined in 2004–2005. The stomach contents of the juvenile, subadult and adult stages of 136 males and 100 females were examined. Diets were broad (32 prey taxa), but dominated by molluscs, teleosts and cephalopods. Analyses of stomach contents data demonstrated that diet differed significantly by ontogenetic stage, but not by sex. Juveniles and subadults consumed mainly benthic infauna and epifauna, with subadults ingesting greater amounts of diogenid crustaceans, and adult diets dominated by demersal/pelagic prey. Trophic level differed ontogenetically, from secondary consumers as juveniles and subadults to tertiary consumers as adults. The mainly tricuspidate juvenile dentition changed with maturity to a greater proportion of large molariform distal teeth, whereas the snout and jaw lengthened and broadened. Adult males retained a greater proportion of anterior S-family teeth than females, which was most likely related to copulation. The ontogenetic variation in dietary composition, facilitated by differences in dentition and mouth morphology, demonstrated that dietary resources were partitioned ontogenetically.

Additional keywords: durophagous, elasmobranch, feeding, ontogeny.


Acknowledgements

The authors thank Australian Geographic and Project A.WAR.E. (PADI Asia Pacific) for financial assistance with this research. Special thanks to Brett Bollinger (commercial fisher) for his cooperation and assistance in obtaining sharks and staff of the Australian Museum for assistance in identifying prey organisms. This manuscript was greatly improved by critical comments from three anonymous reviewers. All work was conducted under the University of Newcastle Ethics Approval 804 0602 and NSW Fisheries Scientific Collection Permit P02/0042 and renewals and complied with Australian law.


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