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

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dc.contributor.author Powter, David en_US
dc.contributor.author Gladstone, William en_US
dc.contributor.editor en_US
dc.date.accessioned 2012-02-02T08:52:31Z
dc.date.available 2012-02-02T08:52:31Z
dc.date.issued 2008 en_US
dc.identifier 2009002255 en_US
dc.identifier.citation Powter David and Gladstone William 2008, 'Demographic analysis of the Port Jackson shark Heterodontus portusjacksoni in the coastal waters of eastern Australia', CSIRO Publishing, vol. 59, pp. 444-455. en_US
dc.identifier.issn 1323-1650 en_US
dc.identifier.other C1UNSUBMIT en_US
dc.identifier.uri http://hdl.handle.net/10453/15048
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 (?1 = 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. en_US
dc.language en_US
dc.publisher CSIRO Publishing en_US
dc.relation.isbasedon http://dx.doi.org/10.1071/MF07096 en_US
dc.title Demographic analysis of the Port Jackson shark Heterodontus portusjacksoni in the coastal waters of eastern Australia en_US
dc.parent Marine and Freshwater Research en_US
dc.journal.volume 59 en_US
dc.journal.number en_US
dc.publocation Australia en_US
dc.identifier.startpage 444 en_US
dc.identifier.endpage 455 en_US
dc.cauo.name SCI.Environmental Sciences en_US
dc.conference Verified OK en_US
dc.for 060200 en_US
dc.personcode 0000059479 en_US
dc.personcode 108858 en_US
dc.percentage 100 en_US
dc.classification.name Ecology en_US
dc.classification.type FOR-08 en_US
dc.edition en_US
dc.custom en_US
dc.date.activity en_US
dc.location.activity en_US
dc.description.keywords conservation, growth rates, matrix models, mortality en_US
dc.staffid en_US
dc.staffid 108858 en_US


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