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dc.contributor.authorJewell, Rebecca Lucy
dc.contributor.authorThomas, Len
dc.contributor.authorHarris, Catriona M
dc.contributor.authorKaschner, Kristin
dc.contributor.authorWiff, Rodrigo Alexis
dc.contributor.authorHammond, Philip Steven
dc.contributor.authorQuick, Nicola Jane
dc.identifier.citationJewell , R L , Thomas , L , Harris , C M , Kaschner , K , Wiff , R A , Hammond , P S & Quick , N J 2012 , ' Global analysis of cetacean line-transect surveys : detecting trends in cetacean density ' , Marine Ecology Progress Series , vol. 453 , pp. 227-240 .
dc.identifier.otherPURE: 21183913
dc.identifier.otherPURE UUID: 8a304fe2-0a69-46ec-9cb9-720f09167780
dc.identifier.otherScopus: 84861037088
dc.identifier.otherORCID: /0000-0002-2381-8302/work/47531646
dc.identifier.otherORCID: /0000-0002-7436-067X/work/29591699
dc.identifier.otherORCID: /0000-0001-9198-2414/work/60887687
dc.description.abstractMeasuring the effect of anthropogenic change on cetacean populations is hampered by our lack of understanding about population status and a lack of power in the available data to detect trends in abundance. Often long-term data from repeated surveys are lacking, and alternative approaches to trend detection must be considered. We utilised an existing database of line transect survey records to determine whether temporal trends could be detected when survey effort from around the world was combined. We extracted density estimates for 25 species and fitted generalised additive models (GAMs) to investigate whether taxonomic, spatial or methodological differences among systematic line-transect surveys affect estimates of density and whether we can identify temporal trends in the data once these factors are accounted for. The selected GAM consisted of 2 parts: an intercept term that was a complex interaction of taxonomic, spatial and methodological factors and a smooth temporal term with trends varying by family and ocean basin. We discuss the trends found and assess the suitability of published density estimates for detecting temporal trends using retrospective power analysis. In conclusion, increasing sample size through combining survey effort across a global scale does not necessarily result in sufficient power to detect trends because of the extent of variability across surveys, species and oceans. Instead, results from repeated dedicated surveys designed specifically for the species and geographical region of interest should be used to inform conservation and management.
dc.relation.ispartofMarine Ecology Progress Seriesen
dc.rights© Inter-Research 2012. This is an open access article.en
dc.subjectMarine mammal densityen
dc.subjectPopulation trendsen
dc.subjectGeneralised additive modellingen
dc.subjectPower analysisen
dc.subjectQL Zoologyen
dc.subjectQA Mathematicsen
dc.subjectSDG 14 - Life Below Wateren
dc.titleGlobal analysis of cetacean line-transect surveys : detecting trends in cetacean densityen
dc.typeJournal articleen
dc.description.versionPublisher PDFen
dc.contributor.institutionUniversity of St Andrews. School of Biologyen
dc.contributor.institutionUniversity of St Andrews. Scottish Oceans Instituteen
dc.contributor.institutionUniversity of St Andrews. Centre for Research into Ecological & Environmental Modellingen
dc.contributor.institutionUniversity of St Andrews. Statisticsen
dc.contributor.institutionUniversity of St Andrews. Marine Alliance for Science & Technology Scotlanden
dc.contributor.institutionUniversity of St Andrews. Sea Mammal Research Uniten
dc.description.statusPeer revieweden

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