Mediterranean mussel Mytilus galloprovincialis - Department of ...

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galloprovincialis (van Erkom Schurink & Griffiths 1992). The water temperatures of the South Africancoast can be broadly grouped as follows (Field & Griffiths 1991):‣ West coast: 8 - 18°C‣ South coast: 15 - 22°C‣ East coast: 22 - 27°CGiven that M. galloprovincialis demonstrates optimal growth rates between 10 and 20°C (van ErkomSchurink & Griffiths 1992), it is clear that culture of M. galloprovincialis is possible in at least 2 ofthese regions; the West and South coast. These temperature zones correspond to the five marineinshore ecozones which comprise South Africa’s 3100 km length coastline – the Namaqua, theSouthwestern Cape, Agulhas, Natal and Delagoa (Sink et al. 2012) (Figure 4). The 2011 Nationalcoastal and marine habitat classification incorporate the following key drivers of marine biodiversitypatterns:‣ Terrestrial and benthic-pelagic connectivity‣ Substrate (consolidated or unconsolidated)‣ Depth and slope‣ Geology, grain size and wave exposure (which interact in the case of beaches)‣ BiogeographyThe current distribution of M. galloprovincialis lies in the Namaqua, Southwestern Cape and Agulhasecozones (Picker & Griffiths 2011).7.1 Culture techniquesIn South Africa, mussel seed (from the offshore larval pool) naturally settles on culture ropes and themussels are then cultivated in suspension. There is currently no import of mussel seed required inSouth Africa. Both long-line and raft culture methods have been trialled, however, due to the highenergy waves which hit most of the coastline, rafts are now the preferred option. During harvesting,immature mussels are collected and reseeded onto ropes to allow for further growth. In SaldanhaBay, the original square mussel rafts are being gradually replaced by a linear design, which allowsincreased water flow beneath the rafts (S. Jackson, Stellenbosch University, pers. comm.).8 Research requirementsThe introduction of M. galloprovincialis to South African waters, its distribution and impacts(ecological and socio-economic) have been well studied in South Africa. However, it is important tocontinue doing biological research on the species with a focus on incidence of parasites, musselmortalities and condition index (FAO 2012).Furthermore, continual evaluation of the distribution range, mariculture efforts and impact of M.galloprovincialis on the environment and on other commercial species, needs to be maintained.Page | 6
Routine monitoring of current M. galloprovincialis populations and their impacts on habitat as wellas research and modelling of their potential range expansion taking into account predicted effects ofclimate change and survival in the marine environment are other important research needs.Figure 4. Map highlighting the five marine inshore ecozones of South Africa (Sink et al. 2012).Page | 7
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Mediterranean mussel Mytilus galloprovincialis - Department of ...

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