Quantitative fish survey of the submarine canyons of the iSimangaliso Wetland Park

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dc.contributor.advisorAttwood, Colinen_ZA
dc.contributor.advisorSink, Kerry Jen_ZA
dc.contributor.authorGeldenhuys, Dale Adamen_ZA
dc.date.accessioned2015-12-02T12:03:38Z
dc.date.available2015-12-02T12:03:38Z
dc.date.issued2015en_ZA
dc.description.abstractThere have been no quantitative studies of fish species associated with the submarine canyons of the north east coast of South Africa. These canyons offer protection to coelacanths Latimeria chalumnae, fish of commercial importance, and a number of protected and endemic species. A fish survey was conducted by remotely operated vehicle (ROV) that captured video footage at depths between 60 m and 160 m. Seven canyons (Island Rock, South Island Rock, Wright, Jesser, Diepgat, Leadsman and Chaka) and one deep reef (Diepgat Deep Reef) spread along 78 km of shelf break were surveyed. Fish were identified and counted in 1143 30-second video segments. Patterns in diversity and abundance were investigated with respect to canyon, depth, and habitat type. The survey found 52 fish species from 23 families. The families Serranidae and Sparidae were well represented. The first submarine images of the critically endangered Seventy†Four seabream are particularly noteworthy. Only three Myliobatidae species represented the Chondrichthyans. Variation in Shannon-Wiener species diversity (H') was influenced by the diversity of habitat (Kruskall†Wallis p<0,0001) and depths (Kruskall†Wallis p<0,0001). Mann†Whitney post hoc tests showed cave to have a higher H' than sandy plain (p<0,001) and wall (p<0,001). H' for margin was greater than sandy plain (p=0,001) and wall (p<0,001). H' for rock outcrop was greater than sandy plain (p=0,006). Fish diversity increased with increasing depth until 90m, thereafter diversity decreased with subsequent depths. Habitat (Permanova p=0,0031) had the strongest influence on fish community composition. No north†south separation in terms of fish diversity (H') among canyons was detected. The results were consistent with similar studies. All canyons were adequately sampled as the rate of discovery of additional species per sample was ≤1%. A minimum of 80 30-second samples per canyon is recommended to survey fish. The survey methods employed during this study are recommended for surveying deep reef fish to allow for meaningful comparative studies.en_ZA
dc.identifier.apacitationGeldenhuys, D. A. (2015). <i>Quantitative fish survey of the submarine canyons of the iSimangaliso Wetland Park</i>. (Thesis). University of Cape Town ,Faculty of Science ,Marine Research (MA-RE) Institute. Retrieved from http://hdl.handle.net/11427/15512en_ZA
dc.identifier.chicagocitationGeldenhuys, Dale Adam. <i>"Quantitative fish survey of the submarine canyons of the iSimangaliso Wetland Park."</i> Thesis., University of Cape Town ,Faculty of Science ,Marine Research (MA-RE) Institute, 2015. http://hdl.handle.net/11427/15512en_ZA
dc.identifier.citationGeldenhuys, D. 2015. Quantitative fish survey of the submarine canyons of the iSimangaliso Wetland Park. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Geldenhuys, Dale Adam AB - There have been no quantitative studies of fish species associated with the submarine canyons of the north east coast of South Africa. These canyons offer protection to coelacanths Latimeria chalumnae, fish of commercial importance, and a number of protected and endemic species. A fish survey was conducted by remotely operated vehicle (ROV) that captured video footage at depths between 60 m and 160 m. Seven canyons (Island Rock, South Island Rock, Wright, Jesser, Diepgat, Leadsman and Chaka) and one deep reef (Diepgat Deep Reef) spread along 78 km of shelf break were surveyed. Fish were identified and counted in 1143 30-second video segments. Patterns in diversity and abundance were investigated with respect to canyon, depth, and habitat type. The survey found 52 fish species from 23 families. The families Serranidae and Sparidae were well represented. The first submarine images of the critically endangered Seventy†Four seabream are particularly noteworthy. Only three Myliobatidae species represented the Chondrichthyans. Variation in Shannon-Wiener species diversity (H') was influenced by the diversity of habitat (Kruskall†Wallis p<0,0001) and depths (Kruskall†Wallis p<0,0001). Mann†Whitney post hoc tests showed cave to have a higher H' than sandy plain (p<0,001) and wall (p<0,001). H' for margin was greater than sandy plain (p=0,001) and wall (p<0,001). H' for rock outcrop was greater than sandy plain (p=0,006). Fish diversity increased with increasing depth until 90m, thereafter diversity decreased with subsequent depths. Habitat (Permanova p=0,0031) had the strongest influence on fish community composition. No north†south separation in terms of fish diversity (H') among canyons was detected. The results were consistent with similar studies. All canyons were adequately sampled as the rate of discovery of additional species per sample was ≤1%. A minimum of 80 30-second samples per canyon is recommended to survey fish. The survey methods employed during this study are recommended for surveying deep reef fish to allow for meaningful comparative studies. DA - 2015 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2015 T1 - Quantitative fish survey of the submarine canyons of the iSimangaliso Wetland Park TI - Quantitative fish survey of the submarine canyons of the iSimangaliso Wetland Park UR - http://hdl.handle.net/11427/15512 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/15512
dc.identifier.vancouvercitationGeldenhuys DA. Quantitative fish survey of the submarine canyons of the iSimangaliso Wetland Park. [Thesis]. University of Cape Town ,Faculty of Science ,Marine Research (MA-RE) Institute, 2015 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/15512en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentMarine Research (MA-RE) Instituteen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherApplied Marine Scienceen_ZA
dc.titleQuantitative fish survey of the submarine canyons of the iSimangaliso Wetland Parken_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
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