Botany & Zoology
Welkom by Universiteit Stellenbosch

Dr Carol Simon

Marine Biology Research Group  - The polychaetes of South Africa​

Main research interests

The culture of oysters and abalone are two of the most important components of mariculture in South Africa.  Both animals are, however, prone to infestation by shell-boring polychaetes, particularly members of the Polydora-group (Polychaeta: Spionidae).  Infestation by these worms may pose a health risk to their hosts and an economic risk to the farmers.  They may, however, also pose an environmental risk if worms are inadvertently carried beyond their natural distribution ranges through the movement, local or international, of the hosts.  My research therefore focuses on aspects of polychaete taxonomy, reproduction and population structure, all of which may have implications for the infestation and spread of shell-infesting worms. 

Over the last few years my research group has been identifying the worms associated primarily with abalone and a range of wild molluscs, including abalone.  We found that farmed abalone are infested by a small percentage of the species that infest wild molluscs and that the most problematic worm is not indigenous and still absent from wild molluscs. More recently we have expanded our focus to include farmed oysters.  Oysters and abalone are cultured differently; abalone are farmed on-shore and can spend up to four years in production while most oysters are grown off-shore for approximately one year before harvesting.  These differences can have a significant impact on the composition of the species infesting the molluscs. 

Of significant concern to us are the consequences of moving molluscs and their worms. Should a non-indigenous worm become established on a farm, it could escape and infest wild molluscs.  They can also be spread within the destination country through the local movement of infesting hosts accelerating the spread in the natural environment. This is particularly important in South Africa where abalone and oyster farms occur in three biogeographical zones, meaning that worms can be transported across natural barriers to dispersal.  Knowledge of the larval developmental modes of the worms will make an important contribution to our understanding of if and how far non-indigenous worms can spread, should they become established in the wild.

Understanding and cataloguing shell-infesting spionid polychaetes is complicated by the presence of many cryptic species – species that are morphologically similar but genetically and reproductively distinct.  This may have exaggerated the current accepted global distribution of many of these species.  Clarifying the taxonomic status, both morphologically and molecularly, forms the final aspect of my research.

Current students/interns/research assistants

Past Students

Stephanie de Lange: Prevalence and intensity of polydorid infestations on farmed oysters

Rachelle Stofberg: The effect of algal secondary metabolites on abalone larval survival

Lauren Flinders: Radula development of Haliotis midae in relation to diatom availability

International collaboration

Prof. Kenneth Halanych, Auburn University, Alabama, USA
Dr. Dan Thornhill, Auburn University, Alabama, USA
Prof. Matt Bentley, University of Newcastle Upon Tyne, UK
Dr Gary Caldwell, University of Newcastle Upon Tyne, UK
Mr. Tim Worsfold, Unicomarine, Letchworth, UK


In print

Boonzaaier, M. Neethling, S., Mouton, A. and Simon, C. 2014. Polydorid polychaetes (Spionidae) on farmed and wild abalone (Haliotis midae) in South Africa: an epidemiological survey. African Journal of Marine Science

David, A.A. and Simon, C.A. 2014. The effect of temperature on larval development of two non-indigenous poecilogonous polychaetes (Annelida: Spionidae) with implications for life history theory, establishment and range expansion. Journal of Experimental Marine Biology and Ecology 461 (2014) 20–30

David, A.A., Matthee, C.A. and Simon, C.A. (2014). Poecilogony in Polydora hoplura (Polychaeta: Spionidae) from commercially important molluscs in South Africa. Mar Biol (2014) 161:887–898 DOI 10.1007/s00227-013-2388-0

Simon, C.A., San Martín, G and Robinson, G. 2014. Two new species of Syllis (Polychaeta: Syllidae) from South Africa, one of them viviparous, with remarks on larval development and vivipary. Journal of the Marine Biological Association of the United Kingdom, 2014, 94(4), 729–746

Simon, C.A. (2011) Polydora and Dipolydora (Polychaeta: Spionidae) associated with molluscs on the south coast of South Africa, with descriptions of two new species. African Invertebrates, 52 (1): 39–50

Stofberg, R.L., Simon, C.A. and Snyman, R.G. (2011) Effects of heavy metals and a diatom-derived aldehyde on the development and survival of Haliotis midae larvae. African Journal of Marine Science, 33 (2) : 339–345

Simon, C.A., Bentley, M.G. and Caldwell, G.S. (2010) 2,4-decadienal: exploring a novel approach for the control of polychaete pests on cultured abalone.  Aquaculture, 310: 52-60.

Simon, C.A., Worsfold, T. Lange, L and Sterley, J. (2010) The genus Boccardia (Polychaeta: Spionidae) associated with mollusc shells on the south coast of South Africa. Journal of the Marine Biological Association, U.K. 90(3), 585–598.

Simon, C.A., Thornhill, D.J. Oyarzun, F. and Halanych, K.M. (2009) Genetic similarity between Boccardia proboscidea from Western North America and cultured abalone, Haliotis midae, in South. Aquaculture 294: 18–24

Simon, C.A. (2009) Pseudopolydora species associated with mollusc shells on the south coast of South African, with a description of Ps. dayii sp. nov. J. Mar Biol. Assoc. UK 89(4): 681-687.

Simon, C.A. and Booth, A. (2007) Population structure and growth of polydorid polychaetes that infest the cultured abalone, Haliotis midae.  African Journal of Marine Science 29(3) 499-509.

Simon, C.A., Ludford, A. and Wynne, S. (2006) Spionid polychaetes infesting cultured abalone, Haliotis midae, in South Africa.  African Journal of Marine Science 28(1): 167-171.

Simon, C.A., Kaiser, H. and Britz, P.J. (2005) The effect of age on the reproductive output of the abalone pest, Terebrasabella heterouncinata (Polychaeta: Sabellidae: Sabellinae). African Journal of Marine Science 27(2): 513-516.

Simon, C.A., Kaiser, H. and Britz, P.J.  (2005) The life history responses of the abalone pest, Terebrasabella heterouncinata, under natural and aquaculture conditions. Mar. Biol. 147(1): 135-144.

Simon, C.A. and Rouse, G.W. (2005) Ultrastructure of spermiogenesis, sperm and the spermatheca of Terebrasabella heterouncinata (Polychaeta: Sabellidae: Sabellinae). Invertebr. Biol. 124(1) 40-50.

Simon, C.A. (2004) Ultrastructure of oogenesis in the abalone pest, Terebrasabella heterouncinata (Polychaeta: Sabellidae: Sabellinae). Invertebr. Reprod. Dev. 46(1): 19-26.

Simon, C.A., Kaiser, H. and Britz, P.J. (2004) The infestation of the abalone, Haliotis midae, by the sabellid, Terebrasabella heterouncinata, under intensive culture conditions, and the influence of infestation on abalone growth. Aquaculture 232: 29-40.

Simon, C.A., Kaiser, H., Booth, A.J. and Britz, P.J. (2002) The effect of diet and live host presence on the growth and reproduction of Terebrasabella heterouncinata. Invert. Reprod. Develop. 41: 227 - 286. Proceedings of the 9th International Congress on Invertebrate Reproduction and Development, Rhodes University, Grahamstown, South Africa.

Simon, C.A. and McQuaid, C.D. (1999) Extracellular digestion in two co-occurring intertidal mussels (Perna perna and Choromytilus meridionalis) and the role of enteric bacteria in their digestive ecology. J. Exp. Mar. Biol. Ecol. 234: 59-81.

Craig, A.J.F.K and Simon, C.A. (1991) Sunbird and sugarbird seasons. Safring News 20: 9-12.

Popular articles

  1. Duvenage, E., and Simon, C.A. (2008) Warmer water boosts perlemoen pests, researchers show.

  2. Simon, C.A. (2006) Polychaetes that infest cultured perlemoen – they’re not just boring worms.