Sexual segregation and abundance trend of whale sharks in southern Mozambique

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dc.contributor.advisorPierce, Simon
dc.contributor.advisorRohner, Chris
dc.contributor.advisorReed, Cecile
dc.contributor.authorAuditore, Lisa-Marie
dc.date.accessioned2023-03-13T14:14:50Z
dc.date.available2023-03-13T14:14:50Z
dc.date.issued2022
dc.date.updated2023-02-20T12:13:54Z
dc.description.abstractCoastal aggregations of endangered whale sharks (Rhincodon typus) consist mainly of juveniles, and most have a strong male bias. Generalised additive models were constructed on a 15-year dataset (2005–2019), from Praia do Tofo, Mozambique, to investigate sexual segregation in relation to environmental conditions. Temporal (year, day of year), and biophysical (sea surface temperature, time from high tide, moon illumination, Indian Ocean dipole index, wind, and chlorophyll a concentration) predictors were modelled in relation to the total, male, and female sightings. Encounter histories of individual sharks were then used in three capture-markrecapture model parameterisations to test for sex-specific demographic variables, and evaluate trends within the constellation. No differences in selected environmental variables were found between males and females, and demographic parameters were similar. Segregation does not occur from a preference for localised habitat conditions; while fewer females are present, they make use of the area similarly to males. Declining annual sighting trends corroborate trends in the seasonal abundance from multi-state open robust design models. Total abundance decreased over the study period (89%), with females (92%) declining at a greater rate than males (81%) suggesting exposure to different conditions or threats. The rapid decline indicates a need for a detailed threat assessment to assess potential causes.
dc.identifier.apacitationAuditore, L. (2022). <i>Sexual segregation and abundance trend of whale sharks in southern Mozambique</i>. (). ,Faculty of Science ,Department of Biological Sciences. Retrieved from http://hdl.handle.net/11427/37425en_ZA
dc.identifier.chicagocitationAuditore, Lisa-Marie. <i>"Sexual segregation and abundance trend of whale sharks in southern Mozambique."</i> ., ,Faculty of Science ,Department of Biological Sciences, 2022. http://hdl.handle.net/11427/37425en_ZA
dc.identifier.citationAuditore, L. 2022. Sexual segregation and abundance trend of whale sharks in southern Mozambique. . ,Faculty of Science ,Department of Biological Sciences. http://hdl.handle.net/11427/37425en_ZA
dc.identifier.ris TY - Master Thesis AU - Auditore, Lisa-Marie AB - Coastal aggregations of endangered whale sharks (Rhincodon typus) consist mainly of juveniles, and most have a strong male bias. Generalised additive models were constructed on a 15-year dataset (2005–2019), from Praia do Tofo, Mozambique, to investigate sexual segregation in relation to environmental conditions. Temporal (year, day of year), and biophysical (sea surface temperature, time from high tide, moon illumination, Indian Ocean dipole index, wind, and chlorophyll a concentration) predictors were modelled in relation to the total, male, and female sightings. Encounter histories of individual sharks were then used in three capture-markrecapture model parameterisations to test for sex-specific demographic variables, and evaluate trends within the constellation. No differences in selected environmental variables were found between males and females, and demographic parameters were similar. Segregation does not occur from a preference for localised habitat conditions; while fewer females are present, they make use of the area similarly to males. Declining annual sighting trends corroborate trends in the seasonal abundance from multi-state open robust design models. Total abundance decreased over the study period (89%), with females (92%) declining at a greater rate than males (81%) suggesting exposure to different conditions or threats. The rapid decline indicates a need for a detailed threat assessment to assess potential causes. DA - 2022_ DB - OpenUCT DP - University of Cape Town KW - Applied Ocean Science LK - https://open.uct.ac.za PY - 2022 T1 - Sexual segregation and abundance trend of whale sharks in southern Mozambique TI - Sexual segregation and abundance trend of whale sharks in southern Mozambique UR - http://hdl.handle.net/11427/37425 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/37425
dc.identifier.vancouvercitationAuditore L. Sexual segregation and abundance trend of whale sharks in southern Mozambique. []. ,Faculty of Science ,Department of Biological Sciences, 2022 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/37425en_ZA
dc.language.rfc3066eng
dc.publisher.departmentDepartment of Biological Sciences
dc.publisher.facultyFaculty of Science
dc.subjectApplied Ocean Science
dc.titleSexual segregation and abundance trend of whale sharks in southern Mozambique
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationlevelMSc
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