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

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Show simple item record Powter, DM Gladstone, W 2012-02-02T08:52:31Z 2008
dc.identifier.citation Marine and Freshwater Research, 2008, 59 (5), pp. 444 - 455
dc.identifier.issn 1323-1650
dc.identifier.other C1UNSUBMIT en_US
dc.description.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. © CSIRO 2008.
dc.language eng
dc.relation.isbasedon 10.1071/MF07096
dc.title Demographic analysis of the Port Jackson shark Heterodontus portusjacksoni in the coastal waters of eastern Australia
dc.type Journal Article
dc.parent Marine and Freshwater Research
dc.journal.volume 5
dc.journal.volume 59
dc.journal.number en_US
dc.publocation Australia en_US
dc.identifier.startpage 444 en_US
dc.identifier.endpage 455 en_US SCI.Environmental Sciences en_US
dc.conference Verified OK en_US
dc.for 0602 Ecology
dc.personcode 108858
dc.percentage 100 en_US Ecology en_US
dc.classification.type FOR-08 en_US
dc.edition en_US
dc.custom en_US en_US
dc.location.activity en_US
dc.description.keywords Conservation
dc.description.keywords Growth rates
dc.description.keywords Matrix models
dc.description.keywords Mortality
pubs.embargo.period Not known
pubs.organisational-group /University of Technology Sydney
pubs.organisational-group /University of Technology Sydney/Faculty of Science
pubs.organisational-group /University of Technology Sydney/Strength - Environmental Science
utslib.copyright.status Closed Access 2015-04-15 12:17:09.805752+10
pubs.consider-herdc false
utslib.collection.history Closed (ID: 3)
utslib.collection.history School of the Environment (ID: 344)

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