Invisible invasion: finding Perna viridis amongst South African green mussels

Simple item page
dc.contributor.advisorGriffiths, Charles Len_ZA
dc.contributor.authorMicklem, Jessica Murielen_ZA
dc.date.accessioned2015-05-04T07:14:00Z
dc.date.available2015-05-04T07:14:00Z
dc.date.issued2014en_ZA
dc.descriptionIncludes bibliographical references.en_ZA
dc.description.abstractNon-indigenous marine organisms are a global cause for concern as they alter ecosystems, displace native species and cause damage to economic structures. Perna viridis is commonly called the Asian green mussel and is native to the Indo-Pacific region. By means of aquaculture, ship fouling and ballast water, P. viridis has successfully spread to eastern Asia, both North and South America in addition to many small Pacific Islands. Their ability to survive a large range of environmental conditions has resulted in successful establishment. Until recently, P. viridis was thought to be geographically isolated from other Perna species and consequently morphological differentiation was of least concern. Differentiation between species of Perna is difficult and therefore molecular methods have been developed for species identification. This research aimed to sample the harbours on the east coast and use a genetic approach to determine if P. viridis is in South Africa. In each of the six harbours, ten sites were chosen and all green mussels were collected. A phylogenetic analysis of the mitochondrial cytochrome c oxidase subunit 1 gene (mtDNA COI) using ten mussels from five of the harbours was performed using the Tamura-3-parameter model to create a Neighbour-Joining tree. A morphological analysis using genetically identified P. perna and P. viridis was performed to determine species level differences. Results showed only one P. viridis sample from Durban Harbour while the 30 P. perna samples were clearly defined into two clades. This grouping of P. perna did not show geographical trends as suggested in previous literature but this may be a result of a smaller sample size or between harbour transport. P. perna ranged in shell colour from brown to blue-green demonstrating the inaccuracy when determining species based on shell colour. The morphological analysis determined only two ways to distinguish between P. perna and P. viridis. Firstly, by examining the mantle papillae, which are enlarged in P. perna. Secondly, examining the pallial line, which is perfectly convex for P. perna whilst the adductor muscle scars in P. viridis extend beyond the pallial line. Further research is needed to allow accurate identification whilst in the field. There is a possibility of P. viridis spreading down the coast to Cape Agulhas and outcompeting the native species in that area and management should be aware of the P. viridis in South Africa, monitoring the area for any evidence of range expansion.en_ZA
dc.identifier.apacitationMicklem, J. M. (2014). <i>Invisible invasion: finding Perna viridis amongst South African green mussels</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Biological Sciences. Retrieved from http://hdl.handle.net/11427/12723en_ZA
dc.identifier.chicagocitationMicklem, Jessica Muriel. <i>"Invisible invasion: finding Perna viridis amongst South African green mussels."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 2014. http://hdl.handle.net/11427/12723en_ZA
dc.identifier.citationMicklem, J. 2014. Invisible invasion: finding Perna viridis amongst South African green mussels. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Micklem, Jessica Muriel AB - Non-indigenous marine organisms are a global cause for concern as they alter ecosystems, displace native species and cause damage to economic structures. Perna viridis is commonly called the Asian green mussel and is native to the Indo-Pacific region. By means of aquaculture, ship fouling and ballast water, P. viridis has successfully spread to eastern Asia, both North and South America in addition to many small Pacific Islands. Their ability to survive a large range of environmental conditions has resulted in successful establishment. Until recently, P. viridis was thought to be geographically isolated from other Perna species and consequently morphological differentiation was of least concern. Differentiation between species of Perna is difficult and therefore molecular methods have been developed for species identification. This research aimed to sample the harbours on the east coast and use a genetic approach to determine if P. viridis is in South Africa. In each of the six harbours, ten sites were chosen and all green mussels were collected. A phylogenetic analysis of the mitochondrial cytochrome c oxidase subunit 1 gene (mtDNA COI) using ten mussels from five of the harbours was performed using the Tamura-3-parameter model to create a Neighbour-Joining tree. A morphological analysis using genetically identified P. perna and P. viridis was performed to determine species level differences. Results showed only one P. viridis sample from Durban Harbour while the 30 P. perna samples were clearly defined into two clades. This grouping of P. perna did not show geographical trends as suggested in previous literature but this may be a result of a smaller sample size or between harbour transport. P. perna ranged in shell colour from brown to blue-green demonstrating the inaccuracy when determining species based on shell colour. The morphological analysis determined only two ways to distinguish between P. perna and P. viridis. Firstly, by examining the mantle papillae, which are enlarged in P. perna. Secondly, examining the pallial line, which is perfectly convex for P. perna whilst the adductor muscle scars in P. viridis extend beyond the pallial line. Further research is needed to allow accurate identification whilst in the field. There is a possibility of P. viridis spreading down the coast to Cape Agulhas and outcompeting the native species in that area and management should be aware of the P. viridis in South Africa, monitoring the area for any evidence of range expansion. DA - 2014 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2014 T1 - Invisible invasion: finding Perna viridis amongst South African green mussels TI - Invisible invasion: finding Perna viridis amongst South African green mussels UR - http://hdl.handle.net/11427/12723 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/12723
dc.identifier.vancouvercitationMicklem JM. Invisible invasion: finding Perna viridis amongst South African green mussels. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 2014 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/12723en_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.titleInvisible invasion: finding Perna viridis amongst South African green musselsen_ZA
dc.typeBachelor Thesis
dc.type.qualificationlevelHonours
dc.type.qualificationnameBSc (Hons)en_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_2014_micklem_jm.pdf
Size:
1.81 MB
Format:
Adobe Portable Document Format
Description:
Download
Collections
Other Theses