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A Re-Evaluation of the Size of the White Shark (Carcharodon carcharias) Population off California, USA

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dc.contributor Australian Institute Of Marine Science
dc.contributor Univ Hawaii Manoa
dc.contributor Monterey Bay Aquarium
dc.contributor Florida Museum Nat Hist
dc.contributor State University System Of Florida
dc.contributor Coastal & Marine Lab
dc.contributor Dept Biol Sci
dc.contributor Australian Inst Marine Sci
dc.contributor Moss Landing Marine Lab
dc.contributor University Of Hawaii Manoa
dc.contributor California State University Long Beach
dc.contributor California State University System
dc.contributor University Of Florida
dc.contributor Florida State Univ
dc.contributor Florida State University
dc.contributor Univ Florida
dc.contributor Florida Program Shark Res
dc.contributor Dept Oceanog
dc.contributor Commonwealth Sci & Ind Res Org Wealth Oceans Flag
dc.contributor Pelag Fisheries Res Program
dc.contributor Commonwealth Scientific & Industrial Research Organisation (csiro)
dc.contributor Moss Landing Marine Laboratories
dc.contributor University Of Hawaii System
dc.contributor Alaska Department Of Fish & Game
dc.contributor Alaska Dept Fish & Game
dc.contributor Calif State Univ Long Beach
dc.contributor Monterey Bay Aquarium Research Institute O'SULLIVAN, JOHN B. CAILLIET, GREGOR M. LOWE, CHRISTOPHER G. WENG, KEVIN C. BURGESS, GEORGE H. BRUCE, BARRY D. GOLDMAN, KENNETH J. GRUBBS, R. DEAN MACNEIL, M. AARON MOLLET, HENRY F. 2015-03-25T04:30:04Z 2017-03-21T00:56:04Z 2015-03-25T04:30:04Z 2019-05-09T01:19:14Z 2015-03-25T04:30:04Z 2015-03-25T04:30:04Z 2017-03-21T00:56:04Z 2019-05-09T01:19:14Z 2014-06-16
dc.identifier.citation Burgess GH, Bruce BD, Cailliet GM, Goldman KJ, Grubbs RD, Lowe CG, MacNeil MA, Mollet HF, Weng KC, O'Sullivan JB (2014) A re-evaluation of the size of the white shark (Carcharodon carcharias) population off California, USA. PLoS ONE 9(6): e98078. en_US
dc.identifier.issn 1932-6203
dc.description.abstract White sharks are highly migratory and segregate by sex, age and size. Unlike marine mammals, they neither surface to breathe nor frequent haul-out sites, hindering generation of abundance data required to estimate population size. A recent tag-recapture study used photographic identifications of white sharks at two aggregation sites to estimate abundance in "central California'' at 219 mature and sub-adult individuals. They concluded this represented approximately one-half of the total abundance of mature and sub-adult sharks in the entire eastern North Pacific Ocean (ENP). This low estimate generated great concern within the conservation community, prompting petitions for governmental endangered species designations. We critically examine that study and find violations of model assumptions that, when considered in total, lead to population underestimates. We also use a Bayesian mixture model to demonstrate that the inclusion of transient sharks, characteristic of white shark aggregation sites, would substantially increase abundance estimates for the adults and sub-adults in the surveyed sub-population. Using a dataset obtained from the same sampling locations and widely accepted demographic methodology, our analysis indicates a minimum all-life stages population size of >2000 individuals in the California subpopulation is required to account for the number and size range of individual sharks observed at the two sampled sites. Even accounting for methodological and conceptual biases, an extrapolation of these data to estimate the white shark population size throughout the ENP is inappropriate. The true ENP white shark population size is likely several-fold greater as both our study and the original published estimate exclude non-aggregating sharks and those that independently aggregate at other important ENP sites. Accurately estimating the central California and ENP white shark population size requires methodologies that account for biases introduced by sampling a limited number of sites and that account for all life history stages across the species' range of habitats.
dc.description.sponsorship We are grateful for thoughts shared by numerous colleagues during informal discussions. We thank Malcolm Francis, Colin Simpfendorfer, Scott Meyer and two anonymous reviewers for their valuable comments on this manuscript, which helped to greatly improve it. Time on this paper for BDB was supported by the Australian Government's National Environmental Research Program, Marine Biodiversity Hub and for KCW by the Joint Institute for Marine and Atmospheric Research.
dc.description.uri en_US
dc.language English
dc.language.iso en en_US
dc.publisher PLoS (OPEN) en_US
dc.relation.ispartof Null
dc.rights Attribution 3.0 Australia *
dc.rights.uri *
dc.subject Behavior
dc.subject Ocean
dc.subject Consequences
dc.subject Eastern Pacific
dc.subject Science & Technology - Other Topics
dc.subject Multidisciplinary Sciences
dc.subject Demography
dc.subject Australian Waters
dc.subject Elasmobranchs
dc.subject Northwest Atlantic
dc.subject Migration
dc.subject Movements
dc.title A Re-Evaluation of the Size of the White Shark (Carcharodon carcharias) Population off California, USA
dc.type journal article en_US
dc.identifier.doi 10.1371/journal.pone.0098078
dc.identifier.wos WOS:000337738600007

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