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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

Sea vase

Ciona intestinalis

Common name:

Sea vase

Scientific name:

Ciona intestinalis

Alternative common names:

Vase tunicate.

Sea vase is highly competitive species that is a major pest of shellfish aquaculture production. Indigenous to the northern Atlantic Ocean, it has been recorded as an invader of harbours in both temperate and tropical climates. In South Africa, it has been recorded in harbours ranging from Saldanha Bay to Durban.

Additional Info

  • Where does this species come from?

    Northern Atlantic Ocean.

    What is its invasive status in South Africa?

    NEMBA Category 3.

    Where in South Africa is it a problem?

    Western Cape, Eastern Cape and KwaZulu-Natal.

    How does it spread?

    Sea vase is spread primarily as a hull fouling species on commercial vessels or it is associated with aquaculture transfers.

    Why is it a problem?

    It is known to reduce the amount of food available in shallow waters and can outcompete indigenous species for space and food. It is also a nuisance in aquaculture farms around the world due to its high fouling tendencies.

    What does it look like?

    Description: Sea vase is a cylindrical, translucent ascidian, ending in a cone-shaped siphon. The opening of the siphon may be bordered in yellow and have orange or red spots, and the body wall is a pale yellow-green with clearly visible muscle bands. The body is usually soft and is commonly 100-150mm in length. Habitat: Sea vase lives attached to submerged rocks or other hard surfaces, such as ropes, chains and boat hulls. It has a cosmopolitan distribution and tolerates organic pollution and a wide range of environmental conditions. It is abundant in ports and marinas all over the world. Breeding: Sea vase is hermaphroditic like many ascidians, making it capable of self-fertilisation, and is also known to exhibit broadcast spawning. Each adult is capable of spawning once a day during the spawning period and can release up to 500 eggs per day. These eggs are released in mucus strings that float and become tangled around other nearby adults or other protrusions.

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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