Does the implementation of a closed fishing season during the breeding season benefit a species? : a per-recruit-based approach using Cymbula granatina as an illustration

dc.contributor.advisorBranch, George Men_ZA
dc.contributor.authorGovender, Anesh ;Arendse, Clementen_ZA
dc.date.accessioned2017-12-08T06:08:27Z
dc.date.available2017-12-08T06:08:27Z
dc.date.issued2004en_ZA
dc.date.updated2017-02-06T12:33:10Z
dc.description.abstractClosed seasons are generally implemented on the presumption that they increase reproductive output of fished populations. This is based on the assumption that the imposition of a closed season during the breeding season allows more individuals to reproduce, as they are not being harvested. I evaluated the validity of imposing closed seasons during the breeding season by creating a simulation model using the limpet Cymbula granatina as a test case and then compared the fol lowing four scenarios: 1) an unharvested population; 2) no closed season imposed; 3) a closed season imposed during the breeding season; and 4) a closed season imposed outside the breeding season, to determine the effects of the latter three situations on the reproductive output and yield. It was determined that closed seasons do not significantly affect the reproductive output of the population and that the timing of closed seasons made no difference to the reproductive output of the population, as the output was the same for populations with closed seasons during the breeding season or outside the breeding season. Survivors, catch in numbers and yield in biomass were affected by the timing of closed seasons, with higher outputs for each obtained when the closed season was closer to the month when individuals become of harvestable size. It was thus concluded that the imposition of a closed season at any time of the year is an effective management measure if imposing the closed season can reduce annual fishing mortality, but the imposition of a closed season specifically during the breeding season with a view to increase reproductive output brings no benefits relative to closure at any other time of the year. Moreover, any closure will be ineffective if it does not also bring about a reduction of annual fishing mortality. The reasons for advocating closure of a fishery during the breeding season are thus based on false grounds in the case of the limpet C. granatina.en_ZA
dc.identifier.apacitation (2004). <i>Does the implementation of a closed fishing season during the breeding season benefit a species? : a per-recruit-based approach using Cymbula granatina as an illustration</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Biological Sciences. Retrieved from http://hdl.handle.net/11427/26495en_ZA
dc.identifier.chicagocitation. <i>"Does the implementation of a closed fishing season during the breeding season benefit a species? : a per-recruit-based approach using Cymbula granatina as an illustration."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 2004. http://hdl.handle.net/11427/26495en_ZA
dc.identifier.citation 2004. Does the implementation of a closed fishing season during the breeding season benefit a species? : a per-recruit-based approach using Cymbula granatina as an illustration. Thesis. University of Cape Town ,Faculty of Science ,Department of Biological Sciences. http://hdl.handle.net/11427/26495en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Govender, Anesh ;Arendse, Clement AB - Closed seasons are generally implemented on the presumption that they increase reproductive output of fished populations. This is based on the assumption that the imposition of a closed season during the breeding season allows more individuals to reproduce, as they are not being harvested. I evaluated the validity of imposing closed seasons during the breeding season by creating a simulation model using the limpet Cymbula granatina as a test case and then compared the fol lowing four scenarios: 1) an unharvested population; 2) no closed season imposed; 3) a closed season imposed during the breeding season; and 4) a closed season imposed outside the breeding season, to determine the effects of the latter three situations on the reproductive output and yield. It was determined that closed seasons do not significantly affect the reproductive output of the population and that the timing of closed seasons made no difference to the reproductive output of the population, as the output was the same for populations with closed seasons during the breeding season or outside the breeding season. Survivors, catch in numbers and yield in biomass were affected by the timing of closed seasons, with higher outputs for each obtained when the closed season was closer to the month when individuals become of harvestable size. It was thus concluded that the imposition of a closed season at any time of the year is an effective management measure if imposing the closed season can reduce annual fishing mortality, but the imposition of a closed season specifically during the breeding season with a view to increase reproductive output brings no benefits relative to closure at any other time of the year. Moreover, any closure will be ineffective if it does not also bring about a reduction of annual fishing mortality. The reasons for advocating closure of a fishery during the breeding season are thus based on false grounds in the case of the limpet C. granatina. DA - 2004 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2004 T1 - Does the implementation of a closed fishing season during the breeding season benefit a species? : a per-recruit-based approach using Cymbula granatina as an illustration TI - Does the implementation of a closed fishing season during the breeding season benefit a species? : a per-recruit-based approach using Cymbula granatina as an illustration UR - http://hdl.handle.net/11427/26495 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/26495
dc.identifier.vancouvercitation. Does the implementation of a closed fishing season during the breeding season benefit a species? : a per-recruit-based approach using Cymbula granatina as an illustration. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 2004 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/26495en_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.otherZoologyen_ZA
dc.subject.otherMarine Biologyen_ZA
dc.titleDoes the implementation of a closed fishing season during the breeding season benefit a species? : a per-recruit-based approach using Cymbula granatina as an illustrationen_ZA
dc.typeBachelor Thesis
dc.type.qualificationlevelHonours
dc.type.qualificationnameBSc (Hons)en_ZA
uct.type.filetype
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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