The influence of environmental variables on the presence of white sharks, Carcharodon carcharias at two popular Cape Town bathing beaches: A generalized additive mixed model

 

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dc.contributor.author Weltz, Kay en_ZA
dc.contributor.author Kock, Alison A en_ZA
dc.contributor.author Winker, Henning en_ZA
dc.contributor.author Attwood, Colin en_ZA
dc.contributor.author Sikweyiya, Monwabisi en_ZA
dc.date.accessioned 2016-01-02T05:06:48Z
dc.date.available 2016-01-02T05:06:48Z
dc.date.issued 2013 en_ZA
dc.identifier.citation Weltz, K., Kock, A. A., Winker, H., Attwood, C., & Sikweyiya, M. (2013). The influence of environmental variables on the presence of white sharks, Carcharodon carcharias at two popular Cape Town bathing beaches: A generalized additive mixed model. PloS one, 8(7), e68554. doi:10.1371/journal.pone.0068554 en_ZA
dc.identifier.uri http://dx.doi.org/10.1371/journal.pone.0068554 en_ZA
dc.identifier.uri http://hdl.handle.net/11427/16171
dc.description.abstract Shark attacks on humans are high profile events which can significantly influence policies related to the coastal zone. A shark warning system in South Africa, Shark Spotters , recorded 378 white shark ( Carcharodon carcharias ) sightings at two popular beaches, Fish Hoek and Muizenberg, during 3690 six-hour long spotting shifts, during the months September to May 2006 to 2011. The probabilities of shark sightings were related to environmental variables using Binomial Generalized Additive Mixed Models (GAMMs). Sea surface temperature was significant, with the probability of shark sightings increasing rapidly as SST exceeded 14°C and approached a maximum at 18°C, whereafter it remains high. An 8 times (Muizenberg) and 5 times (Fish Hoek) greater likelihood of sighting a shark was predicted at 18°C than at 14°C. Lunar phase was also significant with a prediction of 1.5 times (Muizenberg) and 4 times (Fish Hoek) greater likelihood of a shark sighting at new moon than at full moon. At Fish Hoek, the probability of sighting a shark was 1.6 times higher during the afternoon shift compared to the morning shift, but no diel effect was found at Muizenberg. A significant increase in the number of shark sightings was identified over the last three years, highlighting the need for ongoing research into shark attack mitigation. These patterns will be incorporated into shark awareness and bather safety campaigns in Cape Town. en_ZA
dc.language.iso eng en_ZA
dc.publisher Public Library of Science en_ZA
dc.rights This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. en_ZA
dc.rights.uri http://creativecommons.org/licenses/by/4.0 en_ZA
dc.source PLoS One en_ZA
dc.source.uri http://journals.plos.org/plosone en_ZA
dc.subject.other Sharks en_ZA
dc.subject.other Wind en_ZA
dc.subject.other Beaches en_ZA
dc.subject.other Binomials en_ZA
dc.subject.other Conservation science en_ZA
dc.subject.other Predation en_ZA
dc.subject.other Marine conservation en_ZA
dc.subject.other Surface temperature en_ZA
dc.title The influence of environmental variables on the presence of white sharks, Carcharodon carcharias at two popular Cape Town bathing beaches: A generalized additive mixed model en_ZA
dc.type Journal Article en_ZA
dc.rights.holder © 2013 Weltz et al en_ZA
uct.type.publication Research en_ZA
uct.type.resource Article en_ZA
dc.publisher.institution University of Cape Town
dc.publisher.faculty Faculty of Science en_ZA
dc.publisher.department Marine Research (MA-RE) Institute en_ZA
uct.type.filetype Text
uct.type.filetype Image


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This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Except where otherwise noted, this item's license is described as This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.