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German wasp | Vespula germanica

German wasp

Vespula germanica

Coral bush | Ardisia crenata

Coral bush

Ardisia crenata

Purple loosestrife | Lythrum salicaria

Purple loosestrife

Lythrum salicaria

Pom pom weed | Campuloclinium macrocephalum

Pom pom weed

Campuloclinium macrocephalum

Canarybird bush | Crotalaria agatiflora

Canarybird bush

Crotalaria agatiflora

Peanut butter cassia | Senna didymobotrya

Peanut butter cassia

Senna didymobotrya

Rubber vine | Cryptostegia grandiflora

Rubber vine

Cryptostegia grandiflora

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Environmental Programmes

In order to tackle our country’s socio-economic challenges, the government adopted the Outcomes based approach to improve government performance and providing focus on service delivery. find out more

European flat oyster

Ostrea edulis

Common name:

European flat oyster

Scientific name:

Ostrea edulis

Alternative common names:

Common oyster, edible oyster, eetbare oester (Dutch), Essbare euster (German), and European oyster.

Ostrea edulis is a species of oyster. It is a sessile, filter-feeding bivalve mollusc, associated with highly productive estuarine and shallows coastal water habitats.  Each valve differs in shape and size; the left one (the one used by the oyster to attach itself to a surface) is concave, while the right one is flat and fits snugly inside the left. 

Additional Info

  • Where does this species come from?


    What is its invasive status in South Africa?

    NEMBA category 3.

    Where in South Africa is it a problem?

    Western Cape.

    How does it spread?

    They have been intentionally transported around the globe in order to establish or enhance aquaculture ventures. They have been imported into South Africa since 1894.

    Why is it a problem?

    They are well known to act as vectors of marine alien species. These may include the introduced aquaculture species themselves, epi- or infaunal organisms associated with them, disease micro-organisms and multicellular parasites.

    What does it look like?

    Description: European flat oyster is a bivalve mollusc that has an oval or pear shaped shell with a rough, scaly surface. The irregular shell has a distinct hooked beak, patterned with delicate foliation. The two halves (valves) of the shell are different shapes sub circular to circular and inequivalve. Left shell is deeply concave and fixed to the substratum, the right being flat with rougher edges and sitting inside the left acting as a lid. Inner surfaces of both valves are smooth and usually pearly, white or bluish-grey, often with darker blue areas. Valves are held together at their narrow ends by an elastic ligament. No teeth are reported on the hinge. A large central muscle serves to close the valve against the pull of the ligament. The shell is off white, yellowish or cream in colour with light brown or bluish concentric bands on the right valve. Shell consists of a series of chalky layers which may include laminar and hollow chambers. The hard rough grey shell contains a meat that can vary in color from creamy beige to pale grey, in flavour from salty to bland, and in texture from tender to firm. Habitat: They prefer the firm bottoms of mud, rocks, muddy sand, muddy gravel with shells, hard silt, and artificial habitat created with broken shells. They can be found in muddy areas attached to hard surfaces at depths of 9.144 metres. Breeding: European flat oyster is a protandric hermaphrodite, changing sexes generally twice during a single season. Females are fertilized by externally released sperm. It produces between 500 000 and 1 million eggs per spawning. Following an incubation period of 8-10 days, depending on temperature, final release into environment occurs.

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General News Updates

2019 National Symposium on Biological Invasio…


This is your invitation to South Africa's 2019 National Symposium on Biological Invasions. The convention is hosted by the Centre for Invasion Biology (CIB), University of Stellenbosch, and the Biolo... Read more

2019 Invasive Species Training


During the past five years (2014-2018), ISSA invasive species trainers have trained 4 000 in the identification of invasive species and laws pertaining to invasive species across South Africa.  ... Read more

Alien Grass Working Group


Who are we? The South African National Alien Grass Working Group was jointly initiated by the South African Biodiversity Institute (SANBI) and the Centre for Excellence in Invasion Biology (C·I·B) in... Read more

Permits for planting indigenous Cynodon?


On 16 February, 2018, South Africa's Department of Environmental Affairs issued amendments to the regulations and lists relating to the National List of Invasive Species.  Updates to the draft&n... Read more

Invasive species training 2018 dates released


Interested in invasive species?  How much do you know about NEMBA invasive species compliance for landowners and organs of state? The South African Green Industries Council (SAGIC) have released... Read more

Communications post for Africa advertised


The Nature Conservancy has advertised a brand new post:  Communications Manager, Africa Region. Knowledge of invasive species and water would be an asset in this post. See details below:    Job Titl... Read more