Investigation of population abundance, distribution, and population linkage of Indo-Pacific Bottlenose Dolphins (Tursiops aduncus) on the north and south of Zanzibar using mark-recapture and acoustic methods

Simple item page
dc.contributor.advisorJacobs, David Sen_ZA
dc.contributor.advisorBastian, Annaen_ZA
dc.contributor.advisorGridley, Ten_ZA
dc.contributor.advisorElwen, Simonen_ZA
dc.contributor.authorSt Clair-Hughes, Adam James Victoren_ZA
dc.date.accessioned2017-06-06T09:54:52Z
dc.date.available2017-06-06T09:54:52Z
dc.date.issued2017en_ZA
dc.description.abstractPrevious studies, using a variety of methods such as photographic identification, fisheries observer programs, or genetic testing, on Indo-Pacific bottlenose dolphins (Tursiops aduncus) around Zanzibar Island, Tanzania, suggest separate populations around the north and south coasts. However, most research around the island has focused on the south coast, and movement of dolphins around the coastline is poorly understood. Photographic identification data, consisting of dorsal fin images, and acoustic data from dolphin whistles, both collected in 2008, were analysed to examine linkages between north and south Zanzibar. Photographic identification data was applied in a Mark-Recapture framework, using open population models, to generate abundance estimates of 149 (95% CI 128-173) and 120 (95% CI 97-149) individuals for the north and south coasts of Zanzibar respectively. As 16 individuals had moved from the south to the north coast of Zanzibar during the two month study, a combined population estimate of 353 (95% CI 290-430) individuals for Zanzibar Island was also generated. Acoustic analysis of standard whistle parameters was used to investigate whether these learned signals shared features between the putative populations, using whistle data collected in Plettenberg Bay, South Africa as an out-group. Discriminant function analysis of whistle parameters indicated high classification success of whistles recorded from animals in the north location (86.2%), moderate classification success for the outgroup (61.8%), and zero classification success for Zanzibar's south coast population. High misclassification rates for south Zanzibar suggest that these whistles cannot be readily discriminated from those of north Zanzibar. Shared whistle features suggest that learning may take place between individuals moving between localities. Coupled with previous genetic studies, this study suggests female philopatry and male mediated gene flow between the two areas; however, more genetic markers are necessary to test this interpretation. Further work is also necessary to quantify the degree of movement of dolphins around Zanzibar Island, and potential migration into the area, which will assist in developing management plans.en_ZA
dc.identifier.apacitationSt Clair-Hughes, A. J. V. (2017). <i>Investigation of population abundance, distribution, and population linkage of Indo-Pacific Bottlenose Dolphins (Tursiops aduncus) on the north and south of Zanzibar using mark-recapture and acoustic methods</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Oceanography. Retrieved from http://hdl.handle.net/11427/24519en_ZA
dc.identifier.chicagocitationSt Clair-Hughes, Adam James Victor. <i>"Investigation of population abundance, distribution, and population linkage of Indo-Pacific Bottlenose Dolphins (Tursiops aduncus) on the north and south of Zanzibar using mark-recapture and acoustic methods."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Oceanography, 2017. http://hdl.handle.net/11427/24519en_ZA
dc.identifier.citationSt Clair-Hughes, A. 2017. Investigation of population abundance, distribution, and population linkage of Indo-Pacific Bottlenose Dolphins (Tursiops aduncus) on the north and south of Zanzibar using mark-recapture and acoustic methods. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - St Clair-Hughes, Adam James Victor AB - Previous studies, using a variety of methods such as photographic identification, fisheries observer programs, or genetic testing, on Indo-Pacific bottlenose dolphins (Tursiops aduncus) around Zanzibar Island, Tanzania, suggest separate populations around the north and south coasts. However, most research around the island has focused on the south coast, and movement of dolphins around the coastline is poorly understood. Photographic identification data, consisting of dorsal fin images, and acoustic data from dolphin whistles, both collected in 2008, were analysed to examine linkages between north and south Zanzibar. Photographic identification data was applied in a Mark-Recapture framework, using open population models, to generate abundance estimates of 149 (95% CI 128-173) and 120 (95% CI 97-149) individuals for the north and south coasts of Zanzibar respectively. As 16 individuals had moved from the south to the north coast of Zanzibar during the two month study, a combined population estimate of 353 (95% CI 290-430) individuals for Zanzibar Island was also generated. Acoustic analysis of standard whistle parameters was used to investigate whether these learned signals shared features between the putative populations, using whistle data collected in Plettenberg Bay, South Africa as an out-group. Discriminant function analysis of whistle parameters indicated high classification success of whistles recorded from animals in the north location (86.2%), moderate classification success for the outgroup (61.8%), and zero classification success for Zanzibar's south coast population. High misclassification rates for south Zanzibar suggest that these whistles cannot be readily discriminated from those of north Zanzibar. Shared whistle features suggest that learning may take place between individuals moving between localities. Coupled with previous genetic studies, this study suggests female philopatry and male mediated gene flow between the two areas; however, more genetic markers are necessary to test this interpretation. Further work is also necessary to quantify the degree of movement of dolphins around Zanzibar Island, and potential migration into the area, which will assist in developing management plans. DA - 2017 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2017 T1 - Investigation of population abundance, distribution, and population linkage of Indo-Pacific Bottlenose Dolphins (Tursiops aduncus) on the north and south of Zanzibar using mark-recapture and acoustic methods TI - Investigation of population abundance, distribution, and population linkage of Indo-Pacific Bottlenose Dolphins (Tursiops aduncus) on the north and south of Zanzibar using mark-recapture and acoustic methods UR - http://hdl.handle.net/11427/24519 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/24519
dc.identifier.vancouvercitationSt Clair-Hughes AJV. Investigation of population abundance, distribution, and population linkage of Indo-Pacific Bottlenose Dolphins (Tursiops aduncus) on the north and south of Zanzibar using mark-recapture and acoustic methods. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Oceanography, 2017 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/24519en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Oceanographyen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherApplied Marine Scienceen_ZA
dc.titleInvestigation of population abundance, distribution, and population linkage of Indo-Pacific Bottlenose Dolphins (Tursiops aduncus) on the north and south of Zanzibar using mark-recapture and acoustic methodsen_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMScen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
Files
Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
thesis_sci_2017_st_clair_hughes_adam_james_victor.pdf
Size:
2.36 MB
Format:
Adobe Portable Document Format
Description:
Download
Collections
Masters