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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

Grass carp

Ctenopharyngodon idella

Common name:

Grass carp

Scientific name:

Ctenopharyngodon idella

Alternative common names:

White amur.

The grass carp is an herbivorous, freshwater fish species with an elongated, chubby, torpedo-shaped body. This species occurs in lakes, ponds, pools and the backwaters of large rivers, preferring large, slow-flowing or standing water bodies with vegetation.

Additional Info

  • Where does this species come from?

    Eastern Asia, from the Amur River in eastern Russia to the West River in southern China.

    What is its invasive status in South Africa?

    NEMBA Category 1b in national parks, provincial reserves, mountain catchment areas and forestry reserves declared in terms of the Protected Areas Act. NEMBA Category 2 for breeding of grass carp. NEMBA Category 3 in all other discrete catchment systems in which it occurs.

    Where in South Africa is it a problem?

    uMngeni River in KwaZulu-Natal and Mpumalanga.

    How does it spread?

    It spreads via the authorised and unauthorised stocking of grass carp that has taken place for biological control of vegetation. It was introduced into South Africa from Malaysia and Germany between the years of 1967 and 1975.

    Why is it a problem?

    In large numbers, grass carp can remove all aquatic vegetation from a body of water. When this happens, valuable habitat for fish is lost, which can cause fish population imbalances. The loss of all vegetation also reduces the food base for fish, as some aquatic invertebrates rely on aquatic vegetation. Some waterfowl rely on aquatic plants, so an overabundant grass carp population that eliminates all plants can impact waterfowl. Grass carp can also affect water quality. They may carry exotic parasites or diseases that could be transmitted to indigenous fish.

    What does it look like?

    Description: The grass carp grows rapidly and young fish stocked in spring at 20cm can reach 45cm by autumn. Adults often attain nearly 1.2m in length and over 18kg in weight. There are three simple and seven branched rays on the dorsal fin. They are silvery to olive in colour. Habitat: Grass carp prefer the shallow, abundantly vegetated waters of lakes, ponds and the backwaters of large rivers. They require riverine environments with long reaches, high water volume, turbulent flow and warm water temperatures to successfully reproduce. They can tolerate a wide range of water temperatures (near freezing during winter and near 37°C during summer), low oxygen levels and brackish water. Breeding: Grass carp prefer to spawn in large rivers instead of lakes or slower-moving water (however, they have the potential to breed in slower-moving water if need be). This is potentially dangerous as larger rivers flow through many areas, which furthers the invasion.

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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