Baited remote underwater survey of chondrichthyans in False Bay, South Africa

Simple item page
dc.contributor.advisorAttwood, Colinen_ZA
dc.contributor.authorWatson, Ralph Gareth Andrewen_ZA
dc.date.accessioned2015-09-15T10:33:06Z
dc.date.available2015-09-15T10:33:06Z
dc.date.issued2013en_ZA
dc.description.abstractWorldwide, numerous shark populations are in rapid decline due to chronic overfishing. Their slow reproductive capacity make them susceptible to extinction. To monitor the status of chondrichthyan species, the method or combination of methods used should be non-selective, applicable in a variety of habitats and under most environmental conditions. Baited Remote Underwater Video (BRUV) surveys have shown major benefits over traditional capture-based survey methods in multiple areas. They have been shown to be non-extractive, causing no major disturbance to the substrata and its epibenthos. Large, mobile animals that avoid divers and active fishing surveys are detected. The recorded video removes the need for specialist observers to conduct all the fieldwork. The video allows impartial and repeatable measurements and standardizes data collection and training in association with remote taxonomists. The method is also cheaper than alternatives. Ninety-five sites were sampled with 60 minute video recordings across the whole of False Bay during the period of June-July 2012. Fifteen species of chondrichthyans were recorded, of which Haploblepharus edwardsii was the most abundant, being observed at 83 of 95 sites. One hour was sufficient to capture all the chondrichthyans within the observed area as the average time of arrival was about half an hour into the recording. The distribution of the chondrichthyan population was remarkably uniform across the bay. Depth, habitat and substrate type were significant predictors of species composition (P = 0.004, 0.025 and 0.001 respectively). Opportunistic encounters (one individual observed) included Carcharodon carcharias, Squalus megalops, Rhinobatos annulatus and Myliobatis aquila.en_ZA
dc.identifier.apacitationWatson, R. G. A. (2013). <i>Baited remote underwater survey of chondrichthyans in False Bay, South Africa</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Biological Sciences. Retrieved from http://hdl.handle.net/11427/14022en_ZA
dc.identifier.chicagocitationWatson, Ralph Gareth Andrew. <i>"Baited remote underwater survey of chondrichthyans in False Bay, South Africa."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 2013. http://hdl.handle.net/11427/14022en_ZA
dc.identifier.citationWatson, R. 2013. Baited remote underwater survey of chondrichthyans in False Bay, South Africa. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Watson, Ralph Gareth Andrew AB - Worldwide, numerous shark populations are in rapid decline due to chronic overfishing. Their slow reproductive capacity make them susceptible to extinction. To monitor the status of chondrichthyan species, the method or combination of methods used should be non-selective, applicable in a variety of habitats and under most environmental conditions. Baited Remote Underwater Video (BRUV) surveys have shown major benefits over traditional capture-based survey methods in multiple areas. They have been shown to be non-extractive, causing no major disturbance to the substrata and its epibenthos. Large, mobile animals that avoid divers and active fishing surveys are detected. The recorded video removes the need for specialist observers to conduct all the fieldwork. The video allows impartial and repeatable measurements and standardizes data collection and training in association with remote taxonomists. The method is also cheaper than alternatives. Ninety-five sites were sampled with 60 minute video recordings across the whole of False Bay during the period of June-July 2012. Fifteen species of chondrichthyans were recorded, of which Haploblepharus edwardsii was the most abundant, being observed at 83 of 95 sites. One hour was sufficient to capture all the chondrichthyans within the observed area as the average time of arrival was about half an hour into the recording. The distribution of the chondrichthyan population was remarkably uniform across the bay. Depth, habitat and substrate type were significant predictors of species composition (P = 0.004, 0.025 and 0.001 respectively). Opportunistic encounters (one individual observed) included Carcharodon carcharias, Squalus megalops, Rhinobatos annulatus and Myliobatis aquila. DA - 2013 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2013 T1 - Baited remote underwater survey of chondrichthyans in False Bay, South Africa TI - Baited remote underwater survey of chondrichthyans in False Bay, South Africa UR - http://hdl.handle.net/11427/14022 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/14022
dc.identifier.vancouvercitationWatson RGA. Baited remote underwater survey of chondrichthyans in False Bay, South Africa. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 2013 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/14022en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Biological Sciencesen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherApplied Marine Scienceen_ZA
dc.titleBaited remote underwater survey of chondrichthyans in False Bay, South Africaen_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_2013_watson_rga.pdf
Size:
5.13 MB
Format:
Adobe Portable Document Format
Description:
Download
Collections
Masters