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RESEARCH ARTICLE
Contents Vol 59(5)

Demographic analysis of the Port Jackson shark Heterodontus portusjacksoni in the coastal waters of eastern Australia

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

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

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

Marine and Freshwater Research 59(5) 444-455 https://doi.org/10.1071/MF07096
Submitted: 10 May 2007  Accepted: 17 April 2008   Published: 6 June 2008

Abstract

Demographic analyses are used to assess the status and vulnerability of elasmobranchs but their accuracy is often affected by limited basic biological information. Although the Port Jackson shark Heterodontus portusjacksoni (Meyer) is currently not considered at threat, there is insufficient data for eastern Australia to assess this rigorously. The present study determined vital demographic rates of adult and juvenile H. portusjacksoni at four locations on the central and southern coast of New South Wales, Australia from January 2002 to December 2005 using underwater visual census, tag–recapture and samples obtained from a commercial fishery. Natural mortality was low in adults (0.063–0.074 year–1) and juveniles (0.225 year–1), but substantial at the embryonic stage (0.783–0.896 year–1). Adult growth rates (31.4–32.7 mm year–1) were slightly less than that of juveniles (36.8–37.5 mm year–1). Males at both stages grew slightly faster than females. However, H. portusjacksoni had slower growth rates than many other elasmobranch species. Having a low intrinsic rate of increase (r = 0.069 year–1), long generation times (μ1 = 22.5 year) and a low rebound potential, adults are the stage with the greatest impact on population growth. Hence, their life history strategy makes them susceptible to serious decline under exploitation, and management should strive to maintain the adult reproductive stock as a priority.

Additional keywords: conservation, growth rates, matrix models, mortality.


Acknowledgements

We wish to thank Australian Geographic and Project AWARE (PADI Asia Pacific) for financial assistance with this research. Special thanks to Brett Bollinger (commercial fisher) for his cooperation and assistance in obtaining sharks. All work was conducted under the University of Newcastle Ethics Approval 804 0602 and NSW Fisheries Scientific Collection Permit P02/0042 and renewals.


References

Akcakaya, H. R. (2002). Estimating the variance of survival rates and fecundities. Animal Conservation 5, 333–336.
Braccini J. M. (2006). Assessment of ecological risks from effects of fishing to piked spurdog (Squalus megalops) in south-eastern Australia. PhD Thesis, University of Adelaide, Australia.

Branstetter, S. (1987). Age and growth validation of newborn sharks held in laboratory aquaria, with comments on the life history of the Atlantic sharpnose shark, Rhizoprionodon terraenovae. Copeia (2), 291–300.
| Crossref | GoogleScholarGoogle Scholar | Branstetter S. (1990). Early life-history implications of selected carcharhinoid and lamnoid sharks of the Northwest Atlantic. In ‘Elasmobranchs as Living Resources: Advances in the Biology, Ecology, Systematics, and the Status of Fisheries’. (Eds H. L. Pratt, S. H. Gruber and T. Taniuchi.) pp. 17–28. (US Department of Commerce: Washington, DC.)

Brewster-Geisz, K. K. , and Miller, T. J. (2000). Management of the sandbar shark, Carcharhinus plumbeus: implications of a stage-based model. Fishery Bulletin 98, 236–249.
Campana S., Marks L., Joyce W., Hurley P., and Showell M. (1999). An analytical assessment of the porbeagle shark (Lamna nasus) population in the Northwest Atlantic. Canadian Stock Assessment Secretariat Research Document 99/158.

Carlson, J. K. , and Parsons, G. R. (1997). Age and growth of the bonnethead shark, Sphyrna tiburo, from northwest Florida, with comments on clinal variation. Environmental Biology of Fishes 50, 331–341.
| Crossref | GoogleScholarGoogle Scholar | Castro J. I., Woodley C. M., and Brudek R. L. (1999). A preliminary evaluation of the status of shark species. FAO Fisheries Technical Paper No. 380, Rome.

Caswell H. (2001). ‘Matrix Population Models: Construction, Analysis, and Interpretation.’ 2nd edn. (Sinauer Associates: Sunderland, MA.)

Chen, P. , and Yuan, W. (2006). Demographic analysis based on the growth parameter of sharks. Fisheries Research 78, 374–379.
| Crossref | GoogleScholarGoogle Scholar | Compagno L. J. V. (2002). ‘Sharks of the World. An Annotated and Illustrated Catalogue of Shark Species Known To Date. Volume 2. Bullhead, Mackerel and Carpet Sharks (Heterodontiformes, Lamniformes and Orectolobiformes).’ (FAO: Rome.)

Cooch E., and White G. (2002). Program MARK. A Gentle Introduction. Available at http://www.phidot.org/software/mark/docs/book/ [Accessed 15 January 2003].

Cortes, E. (1998). Demographic analysis as an aid in shark stock assessment and management. Fisheries Research 39, 199–208.
| Crossref | GoogleScholarGoogle Scholar | Cortes E. (2004). Life history patterns, demography, and population dynamics. In ‘Biology of Sharks and Their Relatives’. (Eds J. C. Carrier, J. A. Musick and M. R. Heithaus.) pp. 449–469. (CRC Press: Boca Raton, FL.)

Duncan, K. M. , and Holland, K. N. (2006). Habitat use, growth rates and dispersal patterns of juvenile scalloped hammerhead sharks Sphyrna lewini in a nursery habitat. Marine Ecology Progress Series 312, 211–221.
| Crossref | GoogleScholarGoogle Scholar | Gayanilo F. C.Jr, Sparre P., and Pauly D. (2002). FiSAT II User’s Guide. Available at http://www.fao.org/fi/statist/fisoft/fisat/WebHelp/FiSAT2.htm [Accessed 1 May 2005].

Gunderson, D. R. , and Dygert, P. H. (1988). Reproductive effort as a predictor of natural mortality rate. Journal du Conseil: Conseil International pour L’Exploration de la Mer 44, 200–209.
Izzo C. (2005). Aging Port Jackson sharks, Heterodontus portusjacksoni (Meyer 1793), using calcified structures. BSc Honours Thesis, Flinders University, Adelaide, Australia.

Jensen, A. L. (1996). Beverton and Holt life history invariants result from optimal trade-off of reproduction and survival. Canadian Journal of Fisheries and Aquatic Sciences 53, 820–822.
| Crossref | GoogleScholarGoogle Scholar | Krebs C. J. (1985). ‘Ecology: the Experimental Analysis of Distribution and Abundance.’ 3rd edn. (Harper and Row: New York, NY.)

Last P. R., and Stevens J. D. (1994). ‘Sharks and Rays of Australia.’ (CSIRO: Melbourne.)

Manire C. A., and Gruber S. H. (1993). A preliminary estimate of natural mortality of age-0 lemon sharks, Negaprion brevirostris. NOAA Technical Report NMFS 115, Washington, DC.

McLaughlin, R. H. , and O’Gower, A. K. (1971). Life history and underwater studies of a heterodont shark. Ecological Monographs 41, 271–289.
| Crossref | GoogleScholarGoogle Scholar | NSW Department of Primary Industries (2004). Environmental Impact Statement on the Ocean Trawl Fishery in NSW. Public Consultation Document, Cronulla, NSW, Australia.

O’Gower, A. K., and Nash, A. R. (1978). Dispersion of the Port Jackson shark in Australian waters. In ‘Sensory Biology of Sharks, Skates, and Rays’. (Eds E. S. Hodgson and R. F. Mathewson.) pp. 529–544. (Office of Naval Research: Arlington, VA.)

Pauly, D. (1980). On the interrelationships between natural mortality, growth parameters, and mean environmental temperature in 175 fish stocks. Journal du Conseil: Conseil International pour L’Exploration de la Mer 39, 175–192.
Powter D. M. (2006). Conservation biology of the Port Jackson shark, Heterodontus portusjacksoni, in New South Wales. PhD Thesis, University of Newcastle, Australia.

Powter, D. M. , and Gladstone, W. (2008a). Habitat preferences of Port Jackson sharks, Heterodontus portusjacksoni, in the coastal waters of eastern Australia. Proceedings of the Linnean Society of New South Wales 129, 151–165.
Powter D. M., and Gladstone W. The reproductive biology and ecology of the Port Jackson shark, Heterodontus portusjacksoni, in the coastal waters of eastern Australia. Journal of Fish Biology, in press.

Rago, P. J. , Sosebee, K. A. , Brodziak, J. K. T. , Murawski, S. A. , and Anderson, E. D. (1998). Implications of recent increases in catches on the dynamics of Northwest Atlantic spiny dogfish (Squalus acanthias). Fisheries Research 39, 165–181.
| Crossref | GoogleScholarGoogle Scholar | Ramos R. O. (2007). Age and growth estimates for the Port Jackson shark, Heterodontus portusjacksoni (Mayer, 1793), from New South Wales, Australia. PhD Thesis, University of Newcastle, Australia.

Rodda K. R. (2000). Development in the Port Jackson shark embryo. PhD Thesis, University of Adelaide, Australia.

Shark Advisory Group (2004). ‘Australian shark assessment report for the Australian national plan of action for the conservation and management of sharks.’ (Department of Agriculture, Fisheries and Forestry: Canberra.)

Simpfendorfer, C. A. (1999). Mortality estimates and demographic analysis for the Australian sharpnose shark, Rhizoprionodon taylori, from northern Australia. Fishery Bulletin 97, 978–986.
Simpfendorfer C. A. (2004a). Demographic models: life tables, matrix models and rebound potential. In ‘Elasmobranch Fisheries Management Techniques’. (Eds J. A. Musick and R. Bonfil.) pp. 187–204. (APEC Secretariat: Singapore.)

Simpfendorfer C. A. (2004b). Mortality estimation. In ‘Elasmobranch Fisheries Management Techniques’. (Eds J. A. Musick and R. Bonfil.) pp. 165–186. (APEC Secretariat: Singapore.)

Smith, S. E. , Au, D. W. , and Show, C. (1998). Intrinsic rebound potentials of 26 species of Pacific sharks. Marine and Freshwater Research 49, 663–678.
| Crossref | GoogleScholarGoogle Scholar | Sparre P., and Venema S. C. (1998). ‘Introduction to Tropical Fish Stock Assessment. Part 1. Manual.’ (FAO: Rome.)

Stevens, J. D. , Bonfil, R. , Dulvy, N. K. , and Walker, P. A. (2000). The effects of fishing on sharks, rays, and chimaeras (chondrichthyans), and the implications for marine ecosystems. ICES Journal of Marine Science 57, 476–494.
| Crossref | GoogleScholarGoogle Scholar | Strong W. R. (1989). Behavioural ecology of horn sharks, Heterodontus francisci, at Santa Catalina Island, California, with emphasis on patterns of space utilization. MSc Thesis, California State University, Long Beach.

Tovar-Avila J. (2006). Reproduction, age validation, growth determination and effects of fishing on the Port Jackson shark (Heterodontus portusjacksoni) in south-eastern Australia. PhD Thesis, University of Melbourne, Australia.

Whitley G. P. (1950). Development of a Port Jackson shark. Proceedings of the Royal Zoological Society of NSW 1950, 28.