Effects of global climate change on the recruitment of Anchovy in the Southern Benguela upwelling system

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dc.contributor.advisorHewitson, Bruceen_ZA
dc.contributor.advisorRichardson, Anthonyen_ZA
dc.contributor.authorYoung, Shona Lindaen_ZA
dc.date.accessioned2014-11-20T19:42:53Z
dc.date.available2014-11-20T19:42:53Z
dc.date.issued2001en_ZA
dc.descriptionIncludes bibliographical references.en_ZA
dc.description.abstractChanges to global climate patterns, as predicted by many climatologists, will impact on ecosystems in numerous ways. The nutrient-rich waters of marine upwelling environments enable prolific plankton growth, which in turn supports vast shoals of pelagic fish. The nutrient supply is dependent on the strength and direction of winds, which govern the upwelling process as well as turbulence. A change in climate may thus affect the food supply and feeding conditions required by pelagic fish populations. This thesis investigates predicted changes in wind patterns in the southern Benguela system and assesses how these changes may impact on the recruitment of the Cape anchovy, Engraulis capensis. A general circulation model (NCAR Climate System Model) is used to compare a future simulation under double C02 conditions with a simulation of the present day wind regime. Climate change effects on anchovy in the other main upwelling systems, off the coasts of California, Peru and Morocco are also examined. Wind speeds and turbulence off the Agulhas Bank in the southern Benguela system are expected to remain suitable and potentially become even more conducive to spawning in the future. The results show similar mean wind speeds to present day values, a decrease in mean turbulence, a decrease in the frequency of extreme wind speeds and a decrease in the frequency of extreme turbulence during the anchovy spawning season (i.e. September-February). An increase in Lasker events is expected at the Eastern Bank Grid Cell, which suggests that this area may become the preferred spawning habitat in the future. The Cape Town Grid Cell also shows suitable conditions in the future simulation for anchovy spawning and may thus become an alternative spawning location. The West Coast shows an increase in alongshore wind stress and thus an increase in upwelling in the future simulation from November - February. This is likely to increase planktonic food availability and ultimately anchovy recruitment. Future simulations from the Climate System Model show that the upwelling systems off the coasts of California, Peru and Morocco are likely to continue supporting anchovy spawning and may become even more suitable in terms of wind and turbulence regimes.en_ZA
dc.identifier.apacitationYoung, S. L. (2001). <i>Effects of global climate change on the recruitment of Anchovy in the Southern Benguela upwelling system</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Environmental and Geographical Science. Retrieved from http://hdl.handle.net/11427/9749en_ZA
dc.identifier.chicagocitationYoung, Shona Linda. <i>"Effects of global climate change on the recruitment of Anchovy in the Southern Benguela upwelling system."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Environmental and Geographical Science, 2001. http://hdl.handle.net/11427/9749en_ZA
dc.identifier.citationYoung, S. 2001. Effects of global climate change on the recruitment of Anchovy in the Southern Benguela upwelling system. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Young, Shona Linda AB - Changes to global climate patterns, as predicted by many climatologists, will impact on ecosystems in numerous ways. The nutrient-rich waters of marine upwelling environments enable prolific plankton growth, which in turn supports vast shoals of pelagic fish. The nutrient supply is dependent on the strength and direction of winds, which govern the upwelling process as well as turbulence. A change in climate may thus affect the food supply and feeding conditions required by pelagic fish populations. This thesis investigates predicted changes in wind patterns in the southern Benguela system and assesses how these changes may impact on the recruitment of the Cape anchovy, Engraulis capensis. A general circulation model (NCAR Climate System Model) is used to compare a future simulation under double C02 conditions with a simulation of the present day wind regime. Climate change effects on anchovy in the other main upwelling systems, off the coasts of California, Peru and Morocco are also examined. Wind speeds and turbulence off the Agulhas Bank in the southern Benguela system are expected to remain suitable and potentially become even more conducive to spawning in the future. The results show similar mean wind speeds to present day values, a decrease in mean turbulence, a decrease in the frequency of extreme wind speeds and a decrease in the frequency of extreme turbulence during the anchovy spawning season (i.e. September-February). An increase in Lasker events is expected at the Eastern Bank Grid Cell, which suggests that this area may become the preferred spawning habitat in the future. The Cape Town Grid Cell also shows suitable conditions in the future simulation for anchovy spawning and may thus become an alternative spawning location. The West Coast shows an increase in alongshore wind stress and thus an increase in upwelling in the future simulation from November - February. This is likely to increase planktonic food availability and ultimately anchovy recruitment. Future simulations from the Climate System Model show that the upwelling systems off the coasts of California, Peru and Morocco are likely to continue supporting anchovy spawning and may become even more suitable in terms of wind and turbulence regimes. DA - 2001 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2001 T1 - Effects of global climate change on the recruitment of Anchovy in the Southern Benguela upwelling system TI - Effects of global climate change on the recruitment of Anchovy in the Southern Benguela upwelling system UR - http://hdl.handle.net/11427/9749 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/9749
dc.identifier.vancouvercitationYoung SL. Effects of global climate change on the recruitment of Anchovy in the Southern Benguela upwelling system. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Environmental and Geographical Science, 2001 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/9749en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Environmental and Geographical Scienceen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherEnvironmental and Geographical Scienceen_ZA
dc.titleEffects of global climate change on the recruitment of Anchovy in the Southern Benguela upwelling systemen_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMPhilen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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